Diagnosis of prosthetic dentistry. Impressions, clinical stages of manufacturing porcelain and metal crowns. Veneers. Laboratory stages of making of porcelain crowns.
Fundamental principle of diagnostic research in clinical prosthodontics is the study and recognition of the disease to a conclusive diagnosis.
Disease as a violation of vital functions in response to emergency external stimuli or internal environment manifests some common symptoms or signs of a group. Each sign is called a symptom.
There are objective and subjective symptoms.
Subjective symptoms – symptoms that were identified during the survey of the patient (the feelings arising from a period of time and which the patient was not before). Objective symptoms are detected during clinical examination of the patient.
The disease can manifest itself not one but several subjective and objective symptoms, some of which are specific for this disease, while others observed among different diseases. Signs of disease may also be a specific set of symptoms (symptom), called the syndrome. Syndromes differ naturally constancy of occurrence, characterizing certain pathological conditions.
Diagnostic Study provides for the investigation of subjective and objective symptoms, etiology, pathogenesis, clinical picture of disease in a particular patient, his physical and mental health, to establish the degree of morphological and functional nature of the changes that constitute the essence of the disease. Therefore, without knowledge of physiological norms and possible variations of physiological functioning of certain organs, teeth and jaws that make up the system, their topographic and functional relationships difficult to properly formulate a diagnosis and take the necessary therapeutic manipulation.
During the diagnostic investigation of patients in clinical prosthodontics, regardless of the subjective data and of obvious clinical symptoms should be examined zuboschelspna whole system, each of its body, rated the overall body condition, and the clearing and associated the disease, necessity of additional (special) methods.
Habits of medical action in the diagnostic research is focused coherent survey stages: determine the complaints of the patient and study history, objective examination by clinical and special methods (study of morphological changes and functional disorders), establishing the diagnosis (nosological form of the disease) .
Interviews with patients (clarify complaints, history taking).
General registration data about the patient:
1.Surname and name.
2.Age.
3.Place of work.
4.Profession.
5.Adress.
6.First visit to the clinic.
During an interview with a patient trying to find out the reasons for his appeal to the clinic (complaints, subjective feeling), the first signs of illness (illness history), health and living conditions (life history).
During the conversation, it is important to establish contact with patients, try to understand him as a person and gain confidence. You should therefore pay particular attention to the specific patient presenting complaints.
1. The reasons for the appeal to the clinic (patient complaints).
At the beginning of the conversation, the patient explains the causes and nature of those unusual sensations (subjective symptoms) that its concerns. Depending on the pathology of patients may complain of:
• difficulty in chewing food due to lack some or all of the lateral teeth;
• inability to nibble food due to lack teeth;
• stertist or mobility of teeth;
• difficulty opening the mouth.
2. Pain in the gums, mucous membrane, temporomandibular joint, bleeding gums;
• burning sensation in the tongue and taste;
• breach of taste;
• Bad breath;
• fix bad dentures;
• denture base fracture;
• discoloration of the combined fixed structures;
• aesthetic defect
3. Anamnesis existing illness.
It should be noted early signs of disease (when, how and under the influence of reason, according to the patient, the disease began), as developed prior to appeal to the clinic (nature and characteristics of its course), or apply some treatment (type and amount), which was its effectiveness (or the patient meets the prosthesis, and if not, the reasons).
Clinical examination methods:
External review and inspection of the face:
External review of the face, despite the communist considerations should be imperceptible to the patient during a call. During the survey study anatomical, morphological and functional features of the face.
· type of face;
· vertical size of the lower face;
· condition of skin of face and neck;
· ratio of upper and lower lip;
· the position of angles of the mouth;
· The degree of baring the teeth while smiling and talking
· the degree of opening the mouth;
Oral examination:
Assessment of teeth:
• position of each tooth, its shape, color;
• The state of the coronal hard tissue (presence of fillings and artificial crowns);
• Tooth mobility;
The dental examination conduct with: dental mirror, tweezers, dental probe. Application of mirrors allows inspect each tooth on all sides, using tweezers determine mobility of teeth, the probe is used to establish whole surface of the tooth crowns, tooth sensitivity plots, deep of periodontal pocket.
It has been estimated that there are over 65,000 possible combinations of teeth and edentu lous spaces in opposing arches. It would be helpful to classify partially edentulous arches that share common attributes, characteristics, qualities, or traits. Obviously, no single method of classification can be descriptive of any except the most basic types. Several methods of classification of partially edentulous arches have been proposed and are in use. This variety has led to some confusion and disagreement concerning which method should be adopted and which method best classifies all possible configurations.
Although classifications are actually descriptive of the partially edentulous arches, the removable partial denture restoring a particular class of arch is described as a denture of that class. For example, we speak of a Class III or Class I removable partial denture. It is simpler to say /fa Class II partial denture” than it is to say aa partial denture restoring a Class II partially edentulous arch.”
The most familiar classifications are those originally proposed by Kennedy, Cummer, and Bailyn. Classifications have also been proposed by Beckett, Godfrey, Swenson, Friedman, Wilson, Skinner, Applegate, Avant, Miller, and others. It is evident that an attempt should be made to combine the best features of all classifications so that a universal classification can be adopted.
The Kennedy method of classification is probably the most widely accepted classification of partially edentulous arches today. In an attempt to simplify the problem and encourage more universal use of a classification and in the interest of adequate communication, the Kennedy classification will be used in this textbook. The student can refer to the Selected Reading Resources section for information relative to other classifications.
The facial expression is the most common aspect of nonverbal communication, and any deformity or unappealing feature that greets the observer’s eye is bound to influence, and perhaps bias, the messages that arc reccived.
When conversing, people tend to maintain eye contact for between 30 to 60 percent of the time’. If there is concern about the appearance of one’s lace (and of particular interest in this text is the display of the teeth), then it places the person with the concerns at a disadvantage. A person who is self-conscious about his teeth will try to avoid eye contact when at all possible. By not looking directly at his conversational partner, he lends to assume that the partner will also not look directly at him. Unfortunately, this stratagem is rarely successful. Failure to establish eye contact when conversing unintentionally communicates doubt, discomfort, and guilt. Customs officers often assess a person’s lack of eye contact as an indicator of prevarication. An additional problem that may be created is that the observer begins to react to the overt body language and the undesirable messages that are being transmitted rather than to the person’s true and often completely innocuous nature.
The significance of the teeth to smiling and to the face in general should not be underestimated. Teeth contribute an important part to what we term “appearance”. A person’s appearance and, more importantly, his perception of his appearance have a vast influence on his self image, which is proportionally related his confidence.
Confidence, in turn, enhances personal relationships. People look up to and like to have dealings with others who have faith in themselves. This self-assurance is readily recognizable in the conversational manner of a person. Those who master the art of personal relationships are more likely to succeed in today’s highly interactive society.
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Unattractive teeth are particularly detrimental to an individual’s chances of success because they tend to negatively alter perceptions about cleanliness, health, sincerity, and truthfulness.
Which segments of the population are more likely to be concerned with esthetics and self-image?
Single men and women are possibly the most conscious of their appearance. It is this group that consumes the largest share of clothing and cosmetic products. In trying to make themselves attractive to the opposite sex, they have become sensitized to esthetics. Nearly every advertisement in print and on television utilizes models with perfect dentition. Rather than a remote possibility for some, this state is now a basic necessity. In the authors’ experience, it is singles who most commonly seek cosmetic treatment.
Careers are understandably important to both men and women today. Many jobs involve extensive personal contact with both employers and employees. In the process of positioning one’s self for advancement, grooming and appearance are so highly valued that career people regularly attend lectures that discuss everything from hair styling to shoe shining. Certainly, in light of the above discussion of interpersonal communication, teeth form a very great part of a person’s presentability.
As industries are shifting more to service and service-related areas, corporations are recognizing that each employee represents the company to customers and the public. Since corporate self-image is just as important as personal self-image, a company will naturally tend to hire, retain, and promote persons who meet their esthetic requirements, which include neatness, cleanliness, and general appearance. A corporation does not wish to be represented by an employee whose unesthetic smile might harm his self image, which may possibly impair his communicational or negotiating abilities.
The middle-aged and the elderly are often a forgotten group in cosmetic dentistry, but this trend may change. People expect to keep their teeth longer and now expect to keep them better looking as well. The staining and the craze lines that often appear in the forties and fifties are no longer solved by extractions and dentures. This group consists of persons at the height of their careers and in excellent physical shape, and they do not want any reminders that time is progressing relentlessly. Menopause and mid-life crisis are other underlying conditions that may induce this age group to seek extensive cosmetic restructuring of their teeth.
It is occasionally noted with patients who have undergone rejuvenating plastic surgery that their teeth are the oldest appearing facial features. Plastic surgeons must make their patients aware that along with soft tissue procedures, dental cosmetic treatment may be indicated.
Adolescence is a very trying time both emotionally and physically. It is also a period during which peer pressure and the need to be accepted are the strongest. The slightest physical deviation can undermine the confidence of a youngster and possibly affect his continued normal development. Adolescents are constantly preening in front of mirrors, and thus have all the more time to become self-conscious about dental defects. What better way to eliminate these deleterious effects than through a non-invasive, reversible cosmetic procedure.
The above are just a few highlighted examples. Everyone is, to a greater or lesser extent, concerned with self-image and can therefore benefit from an improved dental appearance.
THE RELATIONSHIP BETWEEN APPEARANCE AND SUCCESS
When someone unknown to us is described as a successful person, we immediately form a mental picture. In our minds we have actually created our own ideal of success. While the imagined person will vary greatly from one mind to the next, certain qualities will be present in all cases: the successful person will be confident, well dressed, well groomed, and will invariably be smiling.
Our imagination often guides our expectation, and consciously or subconsciously we attempt to emulate an appearance of success in our own actions. We, too, wish to be smiling, confident, respected, and sure of ourselves.
Will an individual with dental esthetic problems appear to be successful?
If on smiling and conversing the dental problems are visible, then this will create a picture of uncleanliness and/or poor attention to grooming. Such an individual would not be perceived as the responsible type of person to whom one could entrust an important task. After all, it may be felt that if he is inattentive to personal detail, he is just as likely to be careless at work.
This entire case against the person with unesthetic teeth has been made without regard to his personality, integrity, qualifications, and experience. Yet the judgment has been made at the first contact, often the meeting that sets the tone for an entire relationship.
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The cause of the esthetic liability is rarely determined. Whether the factors are neglect, medication, or genetic, seems to have no bearing on the negative impact that poor dental appearance creates in the mind of the observer.
Persons with the esthetic problems described above will often resort to compensatory behavior. This line of action only serves to aggravate the situation.
Some people never smile at all, or at best exhibit a very tight grin. This is not commonly taken as an indication of an outgoing personality, and the person is assumed to be smug, conceited, self-centered, antagonistic, and incapable of being friendly. It is unlikely that this individual will be easily accepted either socially or professionally.
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Others may attempt to compensate by covering their mouths with their hands. Besides making their conversation difficult to understand, this gesture implies self-doubt. While this maneuver may effectively hide the dental problems most of the time, it is unlikely to lead to a successful outcome. Combined unintelligibility and the appearance of insecurity tend to show an individual in a rather poor light.
Yet another compensatory mechanism is the avoided look. The dentally-compromised person looks down or away from a conversational partner. This is interpreted by the observer as shiftiness, uncertainty, or vacillation, and usually the dental imperfection is not at all hidden.
As an individual begins any of these behavior patterns, his partner will lean in or come closer to re-establish greater eye contact. The partner cannot understand why the dentally unes- thetic person is setting up these barriers and he tries to undo them. As there is greater eye-to-eye or eye-to-lip contact, the defensive person becomes ever more insecure and attempts further avoidance.
At any given time, our body language is sending messages to those around us. If these messages are strong and confident ones, we will appear to be successful. As the feedback from others confirms and reinforces these feelings, these perceptions become self-fulfilling. If we do not appear successful due to an unesthetic dentition, and if we radiate messages of antagonism, insecurity, and defensiveness, it is likely that similar feelings will be reflected from those with whom we associate.
It is wrong to assume that a good appearance will guarantee success, but it is a safe bet that a poor appearance will hinder success greatly.
DEVELOPMENT OF PORCELAIN LAMINATE VENEERS
When most dentists think of esthetic dentistry, they commonly think as far back as Dr. Buonocore’s article in 1955 I and no further. This was the beginning of the modern era of resin dentistry, but certainly not the first time that cosmetic laminates were used.
Throughout history, people have attempted to modify their teeth in various ways to correspond with the prevailing values of fashion and taste. But in the early part of this century, a particularly difficult problem arose.
With the advent of photography and motion pictures, a very accurate and lifelike facsimile of an individual could be reproduced. Any disfiguring mark was also reproduced with discomfiting accuracy. Unlike paintings, in which the artist could obligingly touch up the offending areas, film was cruelly truthful, In many still photographs of the nineteenth century, the grain of the film covers facial blemishes to an extent, but, significantly, very few of the subjects are smiling. The dental blemishes are thus covered by the lips. If is probably not an accidcnt that many of our forebears seem so serious and strict; in many instances they were just hiding unsightly teeth.
When the earliest motion pictures were produced, the film was so jumpy that it was impossible to see fine facial features, and close up sequences were rare. Then, in the late 1920s, the talkies arrived. Combined with improved filming and projecting techniques, which made minor details more readily visible,
It became necessary for movie stars to have glamorous smiles. The audience expected nothing less than perfection from their heros and heroines, and reeth were part of the package. Needless to say, not all of those who were, or wanted to be. stars had perfect dentition. Thus necessity led to invention.
Dr. Charles Pincus was a
The only important considerations for Pincus at that time were esthetics, and to a lesser extent, comfort. The dental work had to look good for close-up camera work, to be comfortable in the mouth for extended periods, and to be placed so that it would not interfere with speech.
Ultimately, Pincus developed a porcelain facing that fulfilled these conditions’. He baked a thin layer of porcelain onto platinum foil and designed the appliance so it would not interfere with normal oral function. As you would expect, it was not worn in the mouth continuously. The stars could not eat with their facings and wore them for performing only. They were not bonded onto the teeth (suitable technology not yet having been invented); in fact, they were glued temporarily into place with denture powder.
Thus was born the “Hollywood Smile”. Through the years, this has become the generally accepted lay standard of dental cosmetic excellence. As the world’s exposure to films increased, dentists were besieged with patients desiring the movie stars’ smile. These people did not realize that much of the dental perfection that they saw was as much of an illusion as the rest of the film. They also could not possibly know the limited function of these esthetic prostheses.
Dentists have spent the intervening years trying to catch up to their patients’ expectations. Various materials were used in the technique of Pincus, and they all shared the same major limitation. Without any means of secure attachment to teeth, they were of little practical use. This changed dramatically in 1955 with the discovery of bonding. Finally, dental materials could be securely attached to tooth structure, but the materials available then did not fulfill the needs of esthetic dentistry. The first attempts at esthetic bonding made use of dental acrylic, and were unsuccessful due to the unpleasant taste of the residual monomer, and the stains and mouth odors that the acrylic material retained. It was hardly an esthetic solution.
Then, in 1972, Dr. Alain Rochette published a paper detailing an innovative combination of acid-etched bonding of enamel with a porcelain restoration. The porcelain itself was not etched, but was pre-treated with a coupling agent to promote chemical adhesion of an unfilled resin luting agent. First in French, and later in English,4 he described the successful placement of a custom-fabricated porcelain prosthesis to repair a fractured in- cisal angle.
Unfortunately, although Dr. Rochette reported excellent results over a three year observation period, it seems that his creation was too far ahead of its time, and nothing more was heard of the technique for many years. Instead, the emphasis was placed on improving the plastic dental materials used for direct application to the etched enamel. Acrylics and unfilled resins were followed by filled resins and then macrofill composite resins. Each material represented an improvement over the previous generation of materials, but each in turn was abandoned because none fulfilled the major requirement of esthetic restoration: creation and maintenance of an improved appearance.
For all these attempts, the dream of restoring a dentally compromised patient’s esthetic appearance without resorting to full coverage was just that-a dream. Dentistry had not yet developed a cosmetic and functional device that could be placed on the dentition permanently.
In the 1970’s, a dental cosmetic technique using preformed factory processed plastic laminates was presented to the dental profession5,6 (Mastique, Caulk-Dentsply,
The technique consisted of matching preformed plastic laminates to the teeth to be veneered and then of modifying them chair- side until a fairly close adaptation was achieved.
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Subsequently, as dentists realized the difficulties in adapting plastic laminates, laboratories began fabricating them using a heat molding technique. This again enhanced the use of these veneers for a tie. But the increased use of plastic laminates brought to the fore certain inherent problems with this treatment modality. The most serious drawback was an inadequate bond formed between the composite bonding agent and the plastic laminate. This gave rise to delamina- tion, chipping, and marginal percolation.The entire laminate would often just pop off the tooth, as it did for this patient’s lateral incisor. Some of these failures were due to a weak bond, and some to the memory that the plastic exhibited. When the laminate was in any way stressed into place during the bonding procedure, it tended to spring back to its original shape at some time after. Any pressure at the mmarginal areas chipped off sizable segments of the plastic veneer, leaving portions of the underlying composite exposed. The subsequent differential staining was one of the major causes of cosmetic failure.
The lamistresses were applied, if the veneer did not debond, it would wear very quickly.
The earlier plastic veneers were bonded with self-curing resins. These materials contained amines, which caused discoloration and darkening over time. Such was the situation with the two-year-old plastic veneers over the maxillary lateral incisors shown here.
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The weak marginal area also permitted the percolation of oral fluids under the veneer, in between it and the composite. After a number of years, it was quite common to see pooled areas of stain showing through the plastic.
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The longevity of these laminates caow be evaluated. While some have lasted five years or more, very often the esthetic benefits were gone in two. The plastic veneers done for this patient are typical. The first two photographs were taken about two hours apart, demonstrating that the improvement is both dramatic and immediate. The third photograph, however, which was taken about two years later, shows the disappointing longevity of the preformed plastic laminate system .Plastic laminate veneers were a suitable technique in their own time and, perhaps,had their introductioot coincided with the advent of light-cured microfill composite freehand veneers, they might have gained a greater acceptance and use by the profession. Their greatest contribution to dentistry was that they made the profession aware of the esthetic possibilities of veneering.
DIRECT RESIN VENEERS Michael B Miller, D.D.S.
Direct resin veneers have be.en the glamour procedure in Cosmetic Dentistry and are most responsible for its explosive growth. They permit “instant”, one-appointment enhancement of our patients’ smiles and allow us to control the entire fabrication process, rather than depending on the laboratory. This control, however, places more artistic responsibilities on our shoulders. The dentist must be willing to learn layering, sculpting, and finishing techniques, or these veneers will be frustrating to him and a disaster for his patient.
Direct veneers may be done without any tooth preparation, although the results generally will not be as esthetic as a veneer done after enamel reduction. Even though these veneers are slowly being replaced by porcelain veneers as the optimal esthetic option, freehand veneers still have their place in the Cosmetic repertoire.
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While many materials are used for direct veneering, microfills are the most responsible for the acceptance of this modality. Because of their translucent and polishable nature, microfills can be made to mimic enamel almost as well as porcelain. However, microfill restorations are susceptible to chipping, and the patient must accept the fact that these veneers do require periodic maintenance. To minimize this tendency, direct resin veneers often utilize several layers of various materials, each with its own individual strength.
Since direct veneers are done without laboratory support, there is neither a lab fee nor the chance that the technician will not follow the dentist’s instructions. Considering the lesser cost of this procedure, direct veneers give rise to a lower fee than porcelain. The costs of porcelain veneers unfortunately can be prohibitive to
some people, especially younger patients. In this instance, direct veneers may serve as an entry-level procedure, and may be remade in porcelain at some point in the future when necessary and affordable.
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The opaque was removed. Direct veneers were sculpted onto the teeth, this time including the cuspids, using only one shade of an opaque microfill. This allowed the dark teeth to be covered to the patient’s satisfaction without requiring much time spent with opaquers and tints, which procedures would have resulted in a substantial increase of the fee involved.
The male in this picture had a number of problems: a Class III occlusion, rotated teeth, and (in his own perception) teeth that were too dark. Orthognathic surgery and orthodontics were prescribed prior to cosmetic restorative treatment. The patient declined this treatment plan. He wanted only “straight white teeth”. Initially, the patient was subjected to vital bleaching, but the color improvement was inadequate. The maxillary and mandibular anteriors were then veneered to give the patient the appearance he desired. Bonded veneers were chosen instead of porcelain because the patient wanted such a radical change.
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In the event that the patient is not satisfied after the procedure, or if he ever decides to have his malocclusion corrected, it will be relatively easy to remove the bonded veneers and to replace them with porcelain.There are three basic ways of attaching porcelain lami nates to the sin face of teeth. These use either chemical attachment, micro mechanical attachment, or some combination of the two. CHEMICAL ATTACHMENTChemical attachment, usually known as cementing, has been a workhorse for dentistry, dating back to the earliest times. It is the attachment method which we use to affix crowns, bridges, inlays, and other appliances. To use this technique a dental cemcnt such as zinc oxyphosphate, or polycarboxylatc is mixed and spread in a thin layer between the tooth and the appliance being attached. Chemical bonds form between the cement and both substrates, and ultimately it is these bonds that hold our appliances in place.Unfortunately, the current strengths of cemfioliiig, in the mouth are are quite low. It is for this reason that the dentist must always design restorations in such a way that the demands on the cement are minimal. It is this the reason, for instance, that near parallel walls are desirable for crown preparations.
Dental cements are always used in thin films. The reason for this is that the cements generally display far greater adhesive strength than cohesive strength. In fact, for most dental cements the theoretically ideal film thickness is two molecules thick, even though from a practical standpoint this is virtually unobtainable.
One group of dental cements w hich are particularly interesting to us here are the lightly filled composite resins. These exhibit good adhesive strength, but really excel in the areas of cohesive strength and low solubility. They are severely limited in dental utility due to the pulpal irritation which they cause when placed on freshly cut dentin, but they may be used safely on enamel. Unfortunately, they do not form strong water resistant bonds with either unetched enamel or porcelain.
There is yet another group of materials that is becoming increasingly important in dentistry. Known as “coupling agents”, these materials nearly function as true dental cements. These materials generally have tremendous adhesive strength but such low cohesive strength as to be totally useless as cements by themselves. In combination with other materials, however, they can serve the same purpose as true cements.
A typical example of a coupling agent used in dentistry can be found in attaching BIS- gma resins to porcelain. Porcelain represents a particularly difficult surface for cementation if the cement bonds are to be submerged in water. Bond strengths of 1200 psi in the tensile direction are not unusual when attaching resins to porcelain in a dry environment, but after only 48 hours of submersion the two surfaces nearly fall apart’. Certain intermediary treatments of the surfaces can make an extraordinary difference. For instance, when the porcelain has been coated with a monomolecular layer of an organo- functional silane before being covered by the resin, the bond strength becomes formidable.
By using the fusion process, the total bond strength of porcelain to tooth is increased by 66 percent over simple bonding. When using this process, the dentist is able to adhere porcelain veneers on to the tooth surface with greater tenacity than has ever before been possible. In fact, one report indicated that the strength of the attachment between a porcelain laminate and enamel after the fusing process exceeds the strength of the bond between the enamel and the underlying dentin.
In summary, then, present day fusing is made possible by two things: the mechanical gripping afforded by etching, and the chemical attachment afforded by coupling agents. To better understand exactly what is happening in the fusing process, it is helpful to examine each of the components separately. First we will look at what happens to the tooth.
When a mild acid is placed on the surface of a tooth, a roughened, pitted surface results due to one of the morphological characteristics of human enamel. Microscopically the enamel is composed of bundles of prisms or rods which radiate in a direction from the center of the tooth toward the periphery. Surrounding each of these prisms and serving as “mortar” for them is the substance known as interprismatic enamel. It is because of the difference in resistance to acidic attack between the enamel prisms and the interprismatic enamel that the acid wash creates a retentive surface. In some areas of the enamel, the centers of the prisms erode more rapidly than the interprismatic enamel. In other areas, the reverse will happen, and the interprismatic enamel erodes more thoroughly than the prisms themselves. As a result, four major etching patterns of the enamel are reported in the literature.
The average width of the craters found in the Type I etching pattern is about five microns. It is partly for this reason that many luting agents utilize a filler particle size of no greater than five microns. A generally held belief is that by restricting the particle size to five microns or less it is possible for the filler particles to enter into the lumen of the etched enamel. This characteristic of luting composite is of dubious value, however, since even if penetration of a five micron filler particle may be possible and reasonable with a Type I etching pattern, it is probably of no significance whatever in Types II, III or IV.
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The Type II etching pattern is created when the interprismatic substance erodes more rapidly than the enamel prisms themselves. The resulting surface has been described as looking like a view of treetops when seen from above. The invaginations eroded into the enamel are obviously much narrower than that of the Type I etching pattern, but this surface is still suitable for fusing.It is interesting to note that even though Types I and II etching patterns are exact reverses of each other, they will often occur in adjacent areas of the same tooth, sometimes even in adjacent prisms.
While Type I and II etching patterns are suitable for mechanical retention, Type III is not. In a typical Type III etching pattern, no rod structures are evident. This etching pattern results when the enamel consists of a homogeneous mass rather than the familiar rod and interprismatic enamel structure.
It was recognized early that deciduous teeth frequently exhibit a stratum of homogeneous enamel in their outermost layer. It is because of this homogeneity that an application of acid results in a simple reduction of enamel bulk rather than the differential etch required for mechanical retention. As such, the Type III etching pattern can be troublesome for fusing. To make matters worse, prismless enamel is not confined to deciduous teeth as had once been believed. An increasing number of reports indicate that the cervical two-thirds of premolar and molar crowns is often completely devoid of rod patterns after etchings11,12,13.
Fortunately, the prismless enamel layer is usually confined to the outer 13 to 20 microns of the enamel. It is therefore possible to erode past this prismless layer using the etchant.
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An application of 30 percent orthophos- phoric acid for 60 seconds on enamel usually results in a loss of about 10 microns in surface contour and about 20 micron depth of histo- logic change. Since the prismless enamel usually extends no deeper than 20 microns, it is obviously possible to easily erode past this layer with the application of 30 percent or- thophosphoric acid. Beneath the prismless layer, the underlying structure usually exhibits one of the other three etching patterns. Thus the presence of prismless enamel dictates that the etching time for proper fusing be considerably longer than that required by normal enamel.
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The fourth etching pattern (Type IV), is a combination of Type I and II. It exhibits what at first appears to be a random irregularity in the surface of the enamel. Some dentists believe that the irregularity and apparent randomness of the perforations enlarged into the enamel create the ultimate surface for composite fusing.
Over the first 48 hours, many forces combine to hold the composite in contact with the enamel. These include not only mechanical gripping, but also chemical, and Van der Walls forces. After 48 hours in the mouth, however, the chemical, electronic, and Van der Walls forces diminish to such an extent that they are insignificant. These three forces are effective only when the enamel and composite resin are in extremely intimate contact. Since water has a much greater affinity for both the enamel and composite resin than they have for each other, water from the patients saliva gradually insinuates itself between these two layers, “prying” them apart. After 48 hours, the mechanical retention is all that remains for standard bonding.
Still, this bonding is quite strong. The currently accepted value for the bond strength of composite to etched enamel in both tensile and shear directions is between 980 and 1400 psi. This is extremely high for simple mechanical gripping for these materials. The obvious explanation for this surprisingly high bond strength is that the mechanical bonding is not “simple” at all. During the etching process, the enamel “pores” become enlarged. These pores not only penetrate vertically into the tooth’s surface, but also interconnect (Bergman and Hardwick hypothesize that they are pathways used for transport of ions and tissue fluids). The increase in size of these interconnecting pores allows the relatively large resin molecules to penetrate through the subsurface of enamel and to interconnect with other resin tags. This results in a very high degree of resin interlocking around the enamel crystalite itself.
In order to consistently create these exceptional bond strengths, meticulous attention to detail is required prior to fusing. While enamel is an excellent substrate for fusing, in its natural state there are several mechanical impediments to forming a strong mechanical attachment.
Proteins from saliva continually adsorb to the surface of teeth, even in high abrasion areas. As a result, the enamel is normally covered by a thin organic layer called pellicle18. This pellicle then serves as a point of attachment for plaque. The plaque products, along with solid food constituents and fluids form a continuous plaque/pellicle complex. This layer serves as an effective barrier to etching by mild acids. In 1973 Mura and his co-workers showed that the etchant alone was not sufficient to do the job”. This was further demonstrated by Gwinnett20 in 1976 when he showed that enamel which was etched without a mechanical pre-cleaning was often contaminated by remnants of the pellicle as well as by microorganisms.
The obvious conclusion is that in order to maximize the effectiveness of the etchant, the enamel must be pre-treated with a thorough prophylaxis. The usual cleaning agent is unfluori- dated, unflavored pummice, despite the fact that there is support in the literature that standard prophylaxis paste, even with fluoride, is equal in effectiveness. Much has been written about the potential advantages of using either a rubber cup or a bristle brush to clean the enamel 22,23,24,25 but there appears to be no qualitative differences between a thorough prophylaxis performed with either instrument. Thus the choice seems to be simply a matter of operator preference. There also has been some interest in the possibility of using a diamond bur to lightly “dust over” the enamel, both cleaning the enamel and removing the outermost layer of its surface, and some of the literature supports this method.
If a diamond instrument is used, however, caution must be exercised. Remember that the porcelain laminate has been constructed to carefully fit the tooth; the dimensions should not be randomly altered after the impression has been taken, or placement could be complicated. Prudence also is particularly indicated in the case of some of the less conservative tooth preparations (Type IV,V). If the dentist has already eliminated all the enamel that can be safely removed, then good judgment would dictate that the use of a diamond bur be avoided during the attachment phase.
The method used for cleaning the enamel is not critical. What is absolutely vital, however, is that complete cleaning be achieved on all surfaces to be bonded. This also includes the interproximal areas, as well as any areas on the lingual of the tooth that are going to be covered by porcelain. Also, it is good practice to clean and etch slightly beyond the actual area to be covered by porcelain whenever possible. This will allow for minor discrepancies in placement and for a smoother transition from tooth to porcelain.
The result is that there is nearly always a need to clean the enamel interproximally. This can be achieved using polishing strips or a Prophy Jet (Dentsply,
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ETCHING
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Many etching materials are now on the market. They are all composed of ortho- phosphoric acid of between 35 and 50 percent concentration. Some of them also have been combined with filler to make a gel. While they are all clinically effective, the gels and liquids require two slightly different techniques. In using the liquid, one must continually stir the liquid on the surface of the enamel. Be especially careful to avoid pressing against the enamel during this phase because even slight pressure can burnish the enamel rods and diminish ultimate bond strength. If a gel is used, the stirring is not necessary.
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Once etched and rinsed, the enamel should be completely dried with clean oil- free air. The enamel should have a “frosted” appearance, as shown here.
If it is still glossy, then repeat the etching step. If the acid has been allowed to stay on the enamel too long, the tooth will show an opaque, white, chalky appearance (as opposed to “frosted”) due to the production of an insoluble precipitate. The precipitate stays behind after rinsing, clogging the roughness created by the etching. The result is a diminished bond strength. The solution: repolish the surface and re-etch.
After etching and drying, it is important to avoid contamination of the surface. Among the list of possible contaminants is oil from the fingers, talc from gloves and saliva. Even a few seconds of exposure to saliva is sufficient to diminish the bond strength dramatically. If the etched enamel becomes contaminated, it can be re-activated by a ten second exposure to the etchant. This short treatment with the etchant both cleans the etched surface and raise up its energy level so it will be chemically ready to react with the composite.
By comparison to enamel, the porcelain/ composite interface seems much simpler. Unetched, unglazed porcelain presents a microscopic surface that is somewhat porous. This figure shows unetched/unglazed dental porcelain at a magnification of 200X.
Magnified to 2,400X, it has this appearance.
The application of hydrofluoric acid to this surface not only widens the pores present on the surface, but also cleans away small bits of material from the openings. Here is a sample of dental porcelain that has been etched and magnified to 200X.
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One might think that the thin fragile projections of porcelain that cover the surface of the etched porcelain would not have sufficient strength to serve as an anchorage of attachment in fusing. It should be remembered, however, that each of these projections will be completely surrounded by resin.
As with enamel, there is an optimal period for etching the porcelain. After the optimal period, there is a decrease in the mass of the porcelain, but no improvement in the retentivity of the surface. The optimal time for etching is dependent upon the concentration and mixture of acid used as well as the formula of the porcelain.
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Experience has shown that the optimal time for etching may even be partly dependent upon the exact conditions used to fire the porcelain. Fortunately, the bond strength to etched, si- lanated porcelain is so high that even a substantial variation from the ideal will still yield results beyond those required by the technique. Any bond strength between the composite and porcelain in excess of that between the composite and enamel is unused..
One porcelain manufacturer has specifically formulated a porcelain with components that etch out selectively in order to optimize the etching technique. Etching provides the mechanically retentive portion of the fusing technique on both the tooth and porcelain interfaces. The chemical attachment between the resin and both the etched enamel and etched porcelain is afforded through the use of coupling agents. In the case of the porcelain, the usual coupling agent is a silane. There are many brands of silane currently available in the dental marketplace. Most use either gamma-methacryloxipropyltrimethoxysilane or gamma-Glycidoxypropyltrimethoxysilane.
In the case of the etched enamel, the coupling agent is one of the group of “dentin/enarnel bonding agents”. Most of the present formulations incorporate esters of BIS/gma. Examples of this group are Bondlite, Scotchbond, and Sinterbond. These presumably work by forming chemical bonds between the esters and the calcium or phosphate groups of the tooth structure. This group of coupling agents is extremely suitable for use with porcelain laminates.
On occasion, it becomes necessary to cover over exposed dentin. This could occur, for instance, during a maximum prep, or while covering over a cervical abrasion. While BIS/gma esters are useful for this purpose, several other materials also may be used. These include polyurethane based dentin adhesives, glass ionomer cements, “Bowen’s formula” adhesives, GLUMA, and Scotchbond2. As always, deep areas of dentin exposure must be protected from composite resin. Calcium hydroxide is most often used for this purpose, since eugenol will inhibit setting of composite resin.
The polyurethane based group is exemplified by Dentin Adhesit and Restodent Dentin Bonding Agent. The polyure- thanes are generally created as a condensation polymer between a polyol (from polyesters or polyethers) and a polyfunctional isocyanate. The working assumption is that the polyfunctional isocvanates are responsible for coupling to organic components of the tooth surface and composite resin. For maximum effectiveness, it is therefore necessary to have a dentinal smear layer. If one is not present during the adhesion process, then it should be created. Note that since the polyurethane based dentin adhesives require a dentinal smear layer for attachment, they are inappropriate for use on etched enamel.
“Bowen’s formula” adhesives (also known as the oxylate group) have been reported to achieve 1600 psi bond strength to dentin. This is a formidable tenacity, but is achieved only after multiple procedures that take nearly five minutes to perform.
GLUMA (Columbus Dental,
hyde action on collagen in the dentin and copolymerization of HEMA carbon bonds with the composite resin. One of the main attractions of GLUMA is the fact that the material and technique have been reviewed in the literature since 1984 with consistently impressive results. It was available in Europe for several years before first becoming available in the
For cervical abrasion, many operators find it useful to fill in the defect with glass ionomer cement prior to preparation for the laminate. Later, when the veneer is seated, the glass ionomer is treated as if it were enamel, with the exception of adjusting the etching time to 20 seconds. While glass ionomer does not produce as high bond strengths to dentin as Scotchbond2, GLUMA, or the oxylate systems, it does have the decided advantage of slowly leaching fluoride to the adjacent tooth structure.
PORCELAIN VENEERS INDICATIONS AND CONTRAINDICATIONS
INDICATIONS
There are many indications for porcelain laminate veneers. Included among these indications are the following;
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Stained or darkened teeth. This discoloration arose from she high metallic content of the drinking water that this patient consumed throughout her childhood in the
Hypocalcification. The so-called white “discoloration”, these spots can be as perplexing to the patient and dentist as staining.
Diastemas. These are frequently seen in patients whose jaw and teeth sizes do not match. The mandible may be too large, or the teeth may be too small, or possibly presented after treatment, make porcelain veneers the restoration of choice.
Worn acrylic veneers. There are many patients who have preformed plastic veneers bonded to their teeth. Unfortunately, preformed plastic laminates have a relatively short esthetic lifetime in the mouth. When the positive esthetic effect of the plastic veneer is lost, these patients become ideal candidates for porcelain laminates.
Bonding to existing bridges. Silane fusion allows dentists to bond veneers to both porcelain fused to metal and acrylic veneer bridges. Porcelain laminates thus can be utilized to replace worn or chipped facings on existing bridges. At present, this use is considered a compromise to replacing the entire bridge and should not be considered a permanent solution.
Missing lateral incisors. This common problem is often solved by disguising the cuspid as a lateral incisor. Since the facial aspect of the premolars exhibit caniniform anatomy, the result can be esthetically dramatic.
There are also a few contraindications for the use of porcelain laminates. These
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contraindications include the following:
Insufficient fusible substrate.
The technique used to attach porcelain veneers to teeth has always been most effective with etched enamel. Adequate attachment also has been effected over roughened composite. In the past, the bond strength to dentin has not been considered high enough to warrant the placement of a veneer in the absence of enamel. With the current emergence of the newer dentin bonding agents such as GLUMA (Columbus Dental, St. Louis, Mo.) and Scotchbond II (3M, St. Paul, Minnesota), this contraindication may already have been eliminated.
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Labial version. Teeth that are positioned labially to the arch contour beyond the reasonable depth to which preparation can be taken traditionally have not been veneered. The anticipated bond strength to dentin has always remained below acceptable levels for this technique. As already indicated, it is hoped that with the new generations of dentin bonding agents this restriction will be lifted. Until such time, however, we would continue to recommend that whenever possible such cases should be treated orthodon- tically.
Excessive interdental spacing. This type of situation does not allow full closure of the spaces without creating another esthetic problem-oversized looking teeth. Porcelain laminates can still be used to improve the esthetic situation, but the experienced Cosmetic Dentist will leave some interproximal space.
Poor oral hygiene. The lack of home care is a contraindication to any type of major dental restorative work, including veneers.
Mouthbreathing. When mouthbreathing is present, there is a relatively poor prognosis for the case due to both the eventual decay under the veneers and the potentially shortened lifespan of the materials themselves. The materials experience greater stresses when they are constantly wetted and then desiccated. The dentist, therefore, has a duty to inform certain patients with high lip lines that they do not present ideal oral conditions for porcelain veneers, and the long term prognosis must be guarded.
Some contact sports. Chipped anteriors are sometimes the result of playing various sports without a protective face or mouthguard. If the patient cannot be induced to change his habits, or to at least protect his teeth, veneers are not indicated.
Clenching or bruxing. Clenchers and bruxers are sometimes poor candidates for porcelain veneers for a perhaps surprising reason. Porcelain veneers that extend over onto surfaces which come into contact with the opposing dentition may fracture, but it is more likely that they will wear down any opposing natural teeth creating accelerated wear.
Extreme midline deviation. In those few cases where one of the upper central incisors actually straddles the midline, laminate veneering is not a good solution to the problem. Since veneering cannot create an embrasure or interdental space in the middle of a tooth, it is not reasonable to undertake laminate treatment where esthetic results are unlikely to be achieved.
THE SMILE ANALYSIS
Obviously, the first step in the fabrication of porcelain veneers must be to establish the need for this kind of restorative work and the conditions upon which ultimate success (or failure) will be predicated. If all that is being considered is a single tooth, there is no need for a complete smile analysis. In such cases, the porcelain laminate must be designed to fit harmoniously with the existing dentition. When restoration of a larger section of the dentition is considered, however, the initial evaluation should be the smile analysis. This should be done to help both the dentist and patient examine the general problems that exist and the potential for their solution.
Perhaps in the field of cosmetics more than in any other area of dentistry, it is easy for the dentist to misinterpret the desires of the patient. The patient has little or no knowledge of dentistry and is thus often unable to clearly define his dental goals, or sometimes even what is currently disturbing him. Therefore, the authors suggest regular use of a short but comprehensive questionnaire to help identify and isolate both the problems and the most acceptable treatment goals.
Our questionnaire has been designed with two convergent areas: patient and dentist objective considerations, and patient and dentist subjective considerations. In the former, the dentist is more important because he is the one trained to observe and analyze oral conditions. In the latter, the patient’s concerns are paramount because he will be wearing the final product.
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The objective evaluation is begun by comparing the shape and the size of the teeth in relation to the shape and the size of the head. Current esthetic standards lead us to expect a visual correspondence between these two structures. For example, today’s cosmetic standards lead us to expect long, narrow teeth to occur more frequently in dolicocephalic patients (and, conversely, we would also expect that someone with a wide, round face is likely to possess wider, less angular teeth). This perceived cosmetic relationship is particularly important for case planning when multiple spaces are present, since in such cases the dentist cannot use any existing anterior teeth to estimate the required dimensions.
There is a readily available method of quantifying this analysis in a reproducible manner, which is in turn easy to transmit to a laboratory. A number of years ago, the Dentsply Company created the Trubyte Tooth Indicator (L.D. Caulk Co.,
It is important to remember that this system is but a guide. The dentist must always exercise artistic control in order to achieve the maximum improvement in esthetics.This system classifies faces into four basic typical forms: Square, Square Tapering, Tapering, and Ovoid.
There is a further modification of the first four categories by an additional Ovoid influence. A basic assumption behind the tooth indicator is that if the face and teeth are in harmony, then a more pleasing esthetic condition results. There is no intention here to indicate that the teeth are, or even should be, always related to the proportions of the face. However, if the result of this type of evaluation leads to a more pleasing visual i mpact, then it cannot be ignored in dental cosmetics.
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Softened Forms of the Basic Face Forms. (Reprinted with permission, Dentsply International, Inc.)
The plastic plate is placed in front of a patient’s face, with the nose poking through the specially provided triangular space . The eyes are lined up in the special slits provided, and the mouth is centered. Then, looking from straight ahead, the dentist can determine the shape of the face. It is helpful at this ti me to utilize the vertical guidelines in the plastic face plate. Because these lines clearly delimit various portions of the face, they are particularly useful in trying to decide borderline cases. In short, the face plate helps to focus the dentist’s attention on the details he is seeking and tends to eliminate most of the extraneous input that might make this evaluation more difficult.
The shape of the face also tends to influence the ideal relative convexity (or concavity) of the maxillary central and laterals. This is an area often overlooked by both dentists and technicians, and while such an oversight is not a glaring error, it certainly can have enough of an effect on porcelain veneers to make them appear less lifelike.
The facial shape should be entered on the Smile Analysis Form. Combined with later data on the mesio-distal and vertical space available, the shape will assist in the generation of the specific personalized “mold” to be fabricated.
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The number of teeth exposed to view on smiling will indicate how far distally the dentist should be placing veneers. While it is generally accepted that in order to adequately improve the smile, at least the anterior six maxillary teeth should have veneers, this is plainly not enough for someone who shows the second bicuspid. All the maxillary teeth that are apparent on a regular smile should be treated. While this may sound like a make-work suggestion, the dentist must consider the final result. A patient who has had his six anteriors covered with porcelain veneers may find that his untreated first bicuspids, now particularly unesthetic in comparison with the treated teeth, stand out much more than previously when he smiles.
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In a case where one of the bicuspids is lingual to the arch, for instance, placing a veneer on the adjacent cuspid will increase the apparent malposition of the bicuspid. Therefore, if possible the bicuspid should be covered as well.
For patients seeking partial or incomplete treatment, this problem must be pointed out, or they will be very disappointed in the results. In fact, the dentist should allow the patient, with the help of a mirror, to actually select just how far back the veneers will be done. It is likely that the patient will opt for more teeth than the dentist might have chosen.
The next point of observation is the maxillary high lip line. A full or even a lower thaormal lip is of no great importance, but a raised high lip line may lead to many difficulties. In these cases the location and the finishing of the gingival margins of the veneers is even more critical than usual. The slightest imperfection or incomplete masking will be readily visible, especially to the patient’s eye. Sometimes the only method available to correct an irregular set of gingival margins is with surgery.
With normal lips, these areas are usually hidden, excepting those instances where extreme muscular movements occur. In the high lip line patients, the gingival margin of the upper anteriors is often the visual focusing point. In any case, it is vital that this observation be made before starting the case. A mistake in planning at this point cannot be compensated for after the case is fused in place.
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Another major concern in these patients is the shape and the size of the interproximal spaces. These are the hardest areas to finish veneers in such a way that they both cover the underlying tooth completely and are esthetic and anatomically correct in their own right. A mistake often made by those just beginning to work with porcelain veneers is to make the teeth quite square, and thereby close off much of the interproximal spaces. In a high lip line patient this can be disastrous; the teeth look enormous and unnatural, the so-called “horse-teeth”.
Another consideration found with some high lip line patients is that there is often an associated tendency toward mouthbreathing.
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Misaligned teeth may or may not hinder the placement of veneers, depending on the direction and the degree of misalignment. A lateral incisor in slight linguo-version can easily be built out to the arch contour with a slightly thickened veneer assuming there is adequate mesio-distal clearance.
But a mandibular cuspid in crossbite often limits treatment. If the tooth to be treated is in crossbite, orthodontics may be required prior to cosmetic restoration.
In certain orthodontically classified conditions, such as a bimaxillary protrusion, or a Class II malocclusion, where the maxillary anteriors are already positioned too far labi- ally, adding the bulk (however minimal) of a porcelain veneer will cause a more accentuated esthetic problem. Obviously, this characteristic must be discovered and discussed with the patient at this time.
Some patients’ teeth may have wear facets or even chipping. While these conditions may be minor and not contribute greatly to the esthetic problem, they may be indicative of underlying situations that contraindicate the placement of veneers. Both wear facets and chipping can be the result of a loss of vertical dimension in the posterior region. If this loss cannot be corrected first, then it is unlikely that veneers will succeed in the long term, for they will be subject to the intense and continuous occlusal forces that broke the natural teeth initially.
Any chipped or broken teeth should be noted at this time, as well as the reason for the breakage. If the cause for the destruction cannot be alleviated or at least modified, then there is little hope the porcelain laminates will survive.
Finally, the dentist must evaluate the color and staining of the teeth. This is important for the dentist to understand the difficulty of the ensuing project. The ideal situation for porcelain laminates occurs when the color does not have to be changed. The next most desirable category occurs when the colors of all the teeth have to be changed equally and not greatly. As the tint has to be lightened more, the work becomes more difficult. The hardest situation is one in which the teeth are various different dark shades and they all have to match in the final product.
When determining the final shade for the maxillary anteriors, the dentist should take into consideration the shade of the mandibular anteriors. If the difference in shade between the two arches is too great, the esthetic result will not be pleasing; a decision must be made either to veneer the lower anteriors as well, or to make a less dramatic alteration in the maxilla.
Natural characteristics of the patient’s own dentition, such as translucency and shade gradation, should be incorporated into veneers whenever possible and desirable. Such qualities can greatly enhance the final appearance of a veneer. In order to i nsure harmony with the remaining unlaminated teeth, the dentist should make several observations about the natural teeth’s shading. What is the degree of incisal graying (translu- cency)? Is the degree of coloratioear the cervical a normal amount? Are there any unusual characterizations present, such as craze lines, hypoplastic areas, maverick colors, etc., which would be desirable in the final laminate? A conscientious dentist, working with a competent laboratory technician should have few problems including the above features.
Once the operator has established the facial factors that will govern the overall shape and size of the anterior teeth, it remains to be established that the required space is available and that the veneers can be placed in such a manner as to ensure an esthetic result.
The first guiding figure is the total suggested space for the six maxillary anteriors, determined by using the Trubyte Bioform System of Face and Tooth Form Harmony. This “ideal” width is compared to the space actually available in the mouth, using either the distals of the cuspids or the mesials of the first bicuspids as a reference point. These measurements will enable the dentist to determine the need for larger or smaller teeth.
The second factor that is important in this analysis is the “ideal” width of the central incisor in proportion to the width and contour of the face. The dentist might need to increase the width of the central (and then the other interiors correspondingly), and this measurement will indicate just how wide the tooth can be made before it will look out of proportion with respect to the face. An analysis of this type will indicate, before treatment is begun, whether the diastemas should be closed completely.
It is very important in terms of cosmetic appearances to establish the correct location of the midline. The midline, between the two upper central incisors, has two reference points: the midline of the facial features (eyes, nose, lips), and the midline of the lower anteriors. When the maxillary midline is malpositioned, the entire face seems to be unbalanced. It is therefore, very important to respect the existing midline if it is in the proper location, and if it is not, to recreate an esthetic appearance by placing it correctly. The maxillary and mandibular midlines should be aligned, and both, in turn, must follow the facial lines.
A difficulty arises when the facial and mandibular dental midlines do not coincide. The dentist is faced with a dilemma; whichever alignment he chooses will leave a partially unesthetic appearance. The solution is not to place the maxillary midline in an intermediate position, as this would only compound the problem. The maxillary midline should always be aligned with midline, as these are the two most readily visible landmarks.
It is sometimes preferable for the patient to have orthodontic treatment to align his teeth. Naturally, this solution requires ti me and the willingness of the patient to wear orthodontic appliances. Unfortunately, many patients seeking cosmetic treatment are also seeking to avoid intraoral appliances. Sometimes, however, acceptable esthetics simply cannot be obtained without some tooth movement, and the use of orthodontics and porcelain lamination act in symbiotic fashion to achieve the patient’s desired esthetic results in a minimum amount of time.
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Symmetry in a smile goes beyond having the right number of teeth on each side of the midline. Generally, the corresponding teeth on either side of the arch are similar in size. Any divergence from this balance is observed as an unesthetic feature. Prior to treatment, the dentist must evaluate whether the contralateral teeth are dimensionally balanced. In the case that they are not, he must make sure that there is enough spacing available to restore this balance. If the mesio-distal spacing is unavailable, it should be created by a minimum amount of judicious preparation.
Rotated teeth present a problem in veneering only to the extent that they protrude from the arch contour and present mesio-distal size discrepancies when viewed from the labial. Any portion of the rotated tooth that is labial to the normal facial contour of the arch should be reduced; otherwise, the covering porcelain veneer will protrude in an unappealing manner. Care must be taken to ensure that this preparation does not remove excessive tooth structure; if the reduction involved is very deep into the dentin or the pulp, then obviously this treatment modality is not the one of choice.
If a lateral is rotated 90 degrees with no spaces present on the mesial or distal, then, by virtue of the dimensions bucco-lingually being less than those mesio-distally, there will be inadequate width to place a normal looking lateral veneer. If there is no space available in the arch, then either preparation of the adjacent teeth or illusion creating techniques must be employed to correct this feature.
Another possible problem of rotation is a cuspid in a similar 90 degree position. Here the problem is reversed. The bucco- lingual dimensions of the cuspid are greater than the mesio-distal ones. Therefore, the veneered cuspid will appear too wide. This cannot be corrected by the reduction of the cuspid’s dimensions because this kind of preparation would destroy the interdental contacts and upset the occlusal harmony of the entire mouth. Fortunately, by adjusting the labial prominence of the cuspid more mesially or distally, the apparent size can be controlled.
Vertical Space Analysis
Once the dentist has analyzed the facial form and the mesio- distal influences that contribute to the porcelain veneer design, there remains one additional dimension that requires parameter definition before the procedure can be started.
The Bioform Tooth Form System gives a reading for the approximate vertical height of the central incisor. This figure, in millimeters, refers to the enamel portion of the crown from the incisal edge to the cervical dentino-enamel junction at the mid-point of the tooth. This dimension, along with the previously established central incisor width and facial outline form, gives a total picture of a tooth (and hence the entire anterior region) that is in esthetic harmony with the patient’s face.
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If there is adequate vertical space to allow the required length for the incisors, then the fabrication of the veneer is straightforward. Should the necessary space be lacking, the laboratory will have to resort to lengthening the teeth (or shortening them, as the case may be) through illusion (see chapter 9).
Occlusal interference with the lower incisors could be very damaging. The porcelain of the veneers will abrade the enamel of the mandibular teeth if they are in excessive contact, particularly if the glaze has been removed from the porcelain during finishing procedures. The dentist also must evaluate the potential for excessive contact in extreme protrusive movements. While this is not a likely excursion for the patient, even a single occurrence could fracture a veneer that has too little vertical clearance and a weak incisal edge. Under usual circumstances there should be no hesitation in allowing normal occlusion on the porcelain, including porcelain that is brought over the incisal edge.
Subjective Evaluation
Once the dentist has had a chance to evaluate all of the above, he will want to find out what the patient’s overriding concerns might be.
People are most concerned about the color of their teeth. Often even perfectly healthy, esthetic teeth are deprecated for not having the “Hollywood Look”. Due to many years of reinforcement by television advertising, most patients think their teeth are too yellow. Therefore, the first question asked to the patient often should be “How do you feel about the color of your teeth?”. The manner and content of the patient’s answer will give the dentist important clues as to the potential for successful treatment. The less realistic a patient’s self-evaluation, the more likely that he will be dissatisfied with treatment, no matter how good the result may be. The pickier he is with minor, non- contributory details, the harder he is going to be to please. The closer that he holds the mirror to his mouth before treatment, the closer his inspection after treatment.
The dentist must also determine whether the concern with the color (or appearance) of the teeth is the genuine problem. It may be the outward manifestation of some deeper psychological difficulty. While most dentists have inadequate analytical knowledge to determine this accurately, they usually have enough “people skills” to sniff out unsuitable patients.
Many people view diastemas as undesirable, so when diaste- mas are present, this should be another area of discussion. The patient will answer very readily whether or not the spaces between the teeth bother him. Most often the response will be affirmative; the spaces make him feel less assertive or less confident, or unwilling to open his mouth to smile. Since this particular dental problem is relatively easy to eliminate with veneers, the long term prognosis is excellent unless the diaste- mas are unusually large.
The size and the shape of the teeth are also of concern. One common problem is the peg lateral. In such cases all the teeth are well formed and positioned except for two right in the front of the mouth. Obviously this situation is often distressing, and the patient should be encouraged to express his feelings on the subject. Many people also complain of disproportionately small teeth, since these result in the formation of spaces. Thankfully, these situations are often ideal for porcelain veneers.
Finally, there are a series of points to make to the patient with regards to his appearance that will firmly clarify in his mind whether there is a need for treatment.
First, ask the subjective question: “Would you feel more confident if your smile was improved?”. Of course almost anyone can answer “yes” to this question. In answering, a patient usually will reveal where he hopes his improved appearance will have its greatest impact. This can help the dentist to tailor the treatment more specifically.
Next: “What appearance would you like?”. By specifying the ultimate goal, the patient is focusing both the dentist’s and his own attention on a reproducible model. Thus guided, the dentist can attempt a close approximation, resulting in less frustration for him and greater patient acceptance. Ideally, the patient can bring in a picture of how he would prefer to look. This communication can be augmented through the use of diagnostic wax-ups to be discussed shortly and computer imaging.
It is very important at this stage to involve the patient actively in goal selection and treatment planning. As an informed patient, he will cooperate and appreciate the treatment much more than a patient who is not at all involved with his own smile analysis.
The Diagnostic Wax Up
The importance of communication simply cannot be overemphasized. If the dentist does not clearly understand the patient’s objectives, then it will merely be by chance alone that the expectations are fulfilled. Many times, words will suffice to create a full communication between the parties-but in many cases words are simply not enough. The dentist and patient often do not share a common language when it comes to the details of teeth. In these situations, more is needed.
Three devices have been used to help bridge the gap. Photographs are often used to allow the patient to see what the dentist is describing and to allow the patient to show the dentist what he wants.
Photography can pass from a static to a dynamic tool when combined with the power of computers. This mix can be especially powerful, since the anticipated changes in the patient’s smile can be seen as if in final form, including the full face of the patient.
Still, as tantalizing as the photographic possibilities are, the images remain only two dimensional. At present the only three-dimensional tool we have at our disposal is that of the diagnostic wax-up. In certain cases, dentists may find it necessary to use diagnostic wax-ups for their own planning purposes. While with time and experience, most practitioners will be able to visualize the final esthetic result, the dentist, the technician, and the patient can all benefit from the foresight and clarity of communication provided by pre-treatment wax-ups.
In the end, the patient has the most to gain. He has the least capacity of anticipating both the advantages of treatment and the limitations that exist in his particular case. A verbal explanation by the dentist may create, in the patient’s mind, an entirely different picture from what the dentist is trying to convey. Similarly, the patient’s description of the desired results can be misunderstood by the dentist. A pre-treatment consultation including a wax-up will demonstrate exactly what is possible and what is not. The patient will have realistic expectations for the treatment, and this alone may avoid subsequent dissatisfaction. Since the patient has an opportunity to preview the treatment, he may have some very important contributions of his own to make. There often are aspects of esthetics that may be of great concern to the patient, and yet, due to the fact that they may be of little dental consequence, the dentist may not be sensitive to them. Here, a word to the dentist will allow him to change the bothersome features, thereby ensuring a more acceptable outcome. In addition, making the patient a part of the treatment process lets him feel more positive about the final result.
By utilizing the diagnostic wax-up, the dentist will have had an opportunity to evaluate both the approximate final result and the problems that may arise. It may be decided on the basis of the wax-ups that more space is required and that more tooth structure will have to be reduced, or that it is impossible to close the existing diastemas without enlarging the teeth beyond normal mesio-distal proportion. The practitioner may find that the patient’s requests are unreasonable, in which instance it may be advisable to drop the case if the demands cannot be modified to an acceptable level.
In addition, communication with the laboratory technician is not always one hundred per cent clear, and it is much better for the dentist to find the gremlins at this stage of treatment than with the final porcelain. In short, problems are much more easily handled in wax than in veneers.
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Wax-ups also can be a boon to the technician. Since there is a very clear model of what is desired by both the dentist and the patient, the element of guesswork is eliminated. The laboratory- fabricated porcelain veneer is ideally fused on to the tooth with minimal adjustment and polishing; therefore, if the technician can create a very close to ideal veneer based upon the corrected wax-up, the dentist will have a much easier procedure intra- orally. Of course the number of remakes is considerably reduced.
The wax-up can be prepared by either the laboratory or the dentist. If the technician does the work, there will be an added charge, but this is negligible with respect to both the total price charged for the veneers and the number of problems that can be eliminated.
While dental professionals may be able to appreciate a blue, green, or multi-hued wax tooth, it is unlikely that the patient will share their appreciation. A dentist who does present a case in such a colored wax may find himself explaining for extended periods how the final porcelain will be tooth shaded and not blue.
One area that cannot be previewed with a wax-up is the color change that may be effected with porcelain veneers. The patient must be told repeatedly that the color is only that of the diagnostic wax and that the porcelain will be much more true to life.
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Interestingly, while the diagnostic wax-up is intended to be a communication tool, it also seems to act as a motivator. The authors have noted that in some cases when the patient was considering treatment but was not yet fully committed, wax-ups have had the effect of tipping the scales in favor of treatment.
This patient, for instance, was not sure that veneers could help her appearance, and she was afraid that the teeth would be too big. She initially asked for veneers only on the centrals. Models were taken and sent to the laboratory for diagnostic wax-ups. The technician, following the guidelines from the dentist, began to reshape the teeth. Before showing it to the patient, the diagnostic wax-up should be clean and free of any extraneous wax or material that will detract from the clarity of presentation.
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This finished case demonstrates what is in some aspects a compromise treatment. But since the patient was aware of the limitations beforehand, she was pleased with theresults.
TOOTH PREPARATION FOR PORCELAIN LAMINATE VENEERS
As with amalgam preparations, there is perhaps an unlimited number of possibilities for porcelain laminate preparation types. For teaching purposes, however, we have limited the preparation types to six distinct groups. While these six preparation types should serve as a guide for the dentist, it must always be remembered that differing circumstances of tooth shape, placement, and color must dictate reasonable flexibility in design.
Although the specific details of the various preparation types may vary, the considerations which must be embodied in any preparation design are always the same. The eight cardinal rules for porcelain veneer preparations are:
1) The preparation should be as conservative as possible.
2) It should allow for a covering of approximately
3) II should not penetrate into dentin if at all possible, especially at the borders of the preparation where leakage is most likely.
4) It should allow for a cleansable gingival margin.
5) It should not include any sharp internal angles, especially at the incisal edge where the stresses will be the greatest.
6) It should allow for a path of insertion of the veneer, which is free from undercuts.
7) At least enough clearance must be present interproximally to allow for a mylar strip to be placcd between adjacent teeth during fusing,
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Any area of the tooth which is visually accessible should be covcrcd by porcelain.
Most of these rules are fully self-explanatory and thus need no further clarification. Rule number eight, however, is perhaps the one most ofteeglected. It is extremely common to place veneers that seem to cover all visible areas when viewed directly from the front of the tooth, but which fall short of the mark when seen from an angle. Such is the case in this example. The laminate on the right lateral incisor covers most of the facial areas adequately, but the proximal areas near the gingiva are exposed. Often these areas are adequately hidden with composite at the time of fusing, but after a few years the error in design becomes glaring.
VENEER MARGIN PLACEMENT
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This pitfall can be avoided easily enough, but it requires an acute sensitivity to the problem during preparation and fabrication. Before preparation, the dentist must make sure that there is a path of insertion free from undercuts that allows porcelain to cover all areas visually accessible from any angle. This requires careful observation of the tooth being laminated from various extreme angles to determine
which areas of the tooth are open to view. Only then should the dentist begin any preparation of the tooth. A mistake at this stage cannot be rectified later. Similarly, a failure in the design stage by the laboratory is uncorrectable later. In some cases the interproximal design must be as aggressive as shown here.
It should be emphasized that in principle crown should not change color if you meet certain rules during endodontic manipulations before and after the imposition of permanent seal.
1. Tetracycline teeth.
2. Teeth treated by complete removal of dental pulp with violation of technology, therefore the tooth can zabarvytysya in pink – after root canal resorcinol-formalinovoyu pastes, yellow – containing iodoform paste, and color change can occur after tooth injury .
3. Congenital teeth (hypoplasia).
4. Imperfect amelogenesis – the next cause tooth discoloration. By classification, the proposed NM Chuprinin, distinguish four forms of amelogenesis imperfecta. The first form is absolute indications to manufacture veneers. At this form enamel preserved, it only takes yellow or brown, so this form of amelogenesis imperfecta are often confused with tetracycline teeth.
5. Fluorosis.
6. Pitting medium and heavy gravity, ie where erosion takes half of vestibular tooth surface.
7. Wedge-shaped defects with a comprehensive defeat of hard tissues, not only in depth but also on ploscheni.
8. Pathological stertist hard tissue.
9. Class III cavities when the defects are localized on the medial and lateral surfaces and captured large areas.
10. Enamel demineralization as a result of orthodontic treatment after removal of locks braces.
11. Packed position of upper incisors. Anomaly shape of your teeth. Turn on the tooth axis.
12. Correction of DIA and trem.
13. Skole, formed on the teeth.
14. Recovery set and such that the discolored old fillings.
Contraindications for the manufacture of veneers
– Porcelain veneers are not recommended to install on the affected tooth caries and periodontal diseases. First, you must completely cure these diseases, then you can proceed to install veneers.
– If much of the tooth tissue destroyed by caries or trauma, or there is a large seal, in such cases is not desirable to install porcelain veneers. Because these teeth have already lost a lot of hard tissues, and porcelain veneers do not significantly increase the strength of the tooth. To restore these teeth are ideal tooth crown.
– When installing porcelain veneers Bruxism contraindicated.
Direct bite.
– Teeth with large spots of fluoride, because these teeth, with their multiple deposits fluorides, rare to etch properly. Surfaces are usually unsuitable for attaching veneers.
Stages of production of porcelain veneers.
1 clinical stage.
– preparation for porcelain veneers tooth
Porcelain veneers need to be quite strong, it has a certain thickness. Because the enamel layer is removed with appropriate thickness veneers future.
Minimum thickness of approximately 0,5-
Currently, the clinic is usually used two methods for preparation of teeth veneers. Which method should be preferred, depends on the purpose that we want to achieve. And here it is very important to answer the question – will have to “renew” the tooth on the cutting edge?
In that case, extend the crown of the tooth, choose the method by which dissects the vestibular surfaces with access to cutting edge and in some cases additionally dissects oral surface of the tooth.
If there is no need to lengthen the tooth, you usually choose the method by which dissects only vestibular surface of tooth crowns.
After dissecting the vestibular surfaces should ideally be slightly convex, which is largely determined by the size and thickness of the tooth itself. In the area of gum forming ledge (above the gum, or gum at 0,1-
– Getting a impression.
After removing a layer of enamel, the appropriate thickness veneers future, start to get a impressionof the patient’s teeth. Before obtaining a impression transmitting gum retraction.
Current impression get a – polyester or silicone impression materials, one with known and convenient method for the doctor. Also relieve occlusion.
The selection of Color
The dentist chooses the shade porcelain veneers during the daytime, with the technician and the patient on the scale of the material from which the veneers done.
Making temporary veneers
Typically veneers to produce in the laboratory is 1-2 weeks. This time the dentist produces temporary veneers, which he makes himself at the dentist when you first visit the patient. Since a tooth removed a quantity of enamel, its outer surface may be rough to the touch the tongue. Also, the patient may feel that the tooth was formed cusp or corner. After you remove the layer of enamel tooth can become sensitive to cold and hot. Because dental veneers establishes a temporary tooth turned on. Although you caot install the temporary veneers at this time because he has a reason. Temporary veneers can easily break or jump off a tooth.
Laboratory stage
Dental technician in the laboratory produces printouts obtained by the combined sectional plaster model.
Dental technician produces veneers by firing ceramics refractory model, if the loss of tooth tissues are small they are sufficient support for ceramics. For a large loss of tooth tissues using stronger preskeramiku (after dismantling the combined production model simulates a wax reproduction techniques veneers, forming mold resistant, and produces veneers by replacing the wax to ceramics using ceramic press stamp in the oven for pressing.
2 clinical stage.
Installing Porcelain veneers
Before you install porcelain veneers in place, the dentist evaluates how closely it is adjacent to the tooth, checking form and color veneers. For this, the dentist applies veneers on the tooth, said the deficiencies removes veneers, drives it and eliminates the disadvantages, then applies to the tooth – and so for as long as veneers are not exactly cover the tooth. In most cases, anesthesia is not required.
Evaluation forms veneers. Although porcelain veneers are created as a perfect duplicate of the tooth surface, the patient and the dentist may decide that some elements of veneers should be shortened, rounded to make it even better. Because at this stage is based on freely veneers tooth, it is sometimes difficult to see how the ideal form of veneers.
Evaluation of color veneers.
You must select the most suitable cement, and without its hardening (without cure lamps) krapnuty small amount of cement for veneers and place it on the tooth. So you can see the final color veneers. If the color does not suit (for example, differs from the color of adjacent teeth), you need to replace the shade veneers by using different colored cements.
Be sure to check the bite – if any of the rest of the face veneers of teeth in the mouth.
Once the dentist is sure that tightly covers the tooth veneers, has the correct shape and color correspond with the neighboring teeth to begin cementing veneers.
Known that adhesive veneers only fixing method in which a mutual stabilization of ceramic design and dental tissues. The process of fixing adhesive is quite complicated and time consuming procedure that requires strict implementation of all technological stages according to instructions.
Using koferdama recommended in almost all cases, adhesive fixing, like tabs and veneers.
Adhesive fixing veneers should be carried out on dual composite cement hardening, since additional chemical treatment ensures complete polymerization curing material in those areas where no light penetrates. For fixing veneers using photopolymerization cement paste for fixing the demo allowing you to see the future result, in step adjustment (RELYX Veneer Cement. \ Variolink etc.). Also very successfully be used for fixation fluid composites veneers. For example, liquid nanocomposite Filtek Supreme XT has a sufficiently wide color gamut – 12 shades.
Adhesive fixing technique.
To do this you first need to clear and tooth veneers. Then etch the tooth enamel phosphoric acid gel.
After the mordant layer of enamel on the tooth veneers and tooth put Bond and cement.
After that veneers put on the teeth and after 1-2 minutes light with curring lamp.
Recommendations for the care of veneers.
1). Good home hygiene. Like any other tooth, the tooth with veneers must clear every day, using brushes and flosses. You can use any not very abrasive toothpaste that contains fluoride.
Good oral hygiene minimizes the chance of tooth decay on the parts not covered with veneers. Proper removal of plaque will help to ensure that the level of gum to the tooth is not reduced because of inflammation. In most cases the top of the veneers ends at the gums.
2). Do not expose to excessive force veneers. Porcelain is not intended to deal with it. Do not bite nails, the hair ends, ice, do not open the bottle teeth, it can easily crack or shift veneers. If the patient is engaged in contact sports.
3) If patient have bruxism porcelain veneers can easily break. We need to do night
4). Minimize the effect of colorant.
4). Minimize the effect of colorant.
In dentistry, a veneer is a thin layer of restorative material placed over a tooth surface, either to improve the aesthetics of a tooth, or to protect a damaged tooth surface. There are two main types of material used to fabricate a veneer, composite and dental porcelain. A composite veneer may be directly placed (built-up in the mouth), or indirectly fabricated by a dental technician in a dental laboratory, and later bonded to the tooth, typically using a resin cement such as Panavia. In contrast, a porcelain veneer may only be indirectly fabricated.
Dental veneers (sometimes called porcelain veneers or dental porcelain laminates) are wafer-thin, custom-made shells of tooth-colored materials designed to cover the front surface of teeth to improve your appearance. These shells are bonded to the front of the teeth changing their color, shape, size, or length.
Dental veneers can be made from porcelain or from resin composite materials. Porcelain veneers resist stains better than resin veneers and better mimic the light reflecting properties of natural teeth. Resin veneers are thinner and require removal of less of the tooth surface before placement. You will need to discuss the best choice of veneer material for you with your dentist.
What Types of Problems Do Dental Veneers Fix?
Veneers are routinely used to fix:
Teeth that are discolored — either because of root canal treatment; stains from tetracycline or other drugs, excessive fluoride or other causes; or the presence of large resin fillings that have discolored the tooth
Teeth that are worn down
Teeth that are chipped or broken
Teeth that are misaligned, uneven, or irregularly shaped (for example, have craters or bulges in them)
Teeth with gaps between them (to close the space between these teeth)
What’s the Procedure for Getting a Dental Veneer?
Getting a dental veneer usually requires three trips to the dentist – one for a consultation and two to make and apply the veneers. One tooth or many teeth can simultaneously undergo the veneering process described below.
Diagnosis and treatment planning. This first step involves active participation between you and your dentist. Explain to your dentist the result that you are trying to achieve. During this appointment your dentist will examine your teeth to make sure dental veneers are appropriate for you and discuss what the procedure will involve and some of its limitations. He or she also may take X-rays and possibly make impressions of your mouth and teeth.
Preparation. To prepare a tooth for a veneer, your dentist will remove about 1/2 millimeter of enamel from the tooth surface, which is an amount nearly equal to the thickness of the veneer to be added to the tooth surface. Before trimming off the enamel, you and your dentist will decide the need for a local anesthetic to numb the area. Next, your dentist will make a model or impression of your tooth. This model is sent out to a dental laboratory, which in turn constructs your veneer. It usually takes 1 to 2 weeks for your dentist to receive the veneers back from the laboratory. For very unsightly teeth, temporary dental veneers can be placed for an additional cost.
Bonding . Before the dental veneer is permanently cemented to your tooth, your dentist will temporarily place it on your tooth to examine its fit and color. He or she will repeatedly remove and trim the veneer as needed to achieve the proper fit; the veneer color can be adjusted with the shade of cement to be used. Next, to prepare your tooth to receive the veneer, your tooth will be cleaned, polished, and etched — which roughens the tooth to allow for a strong bonding process. A special cement is applied to the veneer and the veneer is then placed on your tooth. Once properly position on the tooth, your dentist will apply a special light beam to the dental veneer, which activates chemicals in the cement causing it to harden or cure very quickly. The final steps involve removing any excess cement, evaluating your bite and making any final adjustments in the veneer as necessary. Your dentist may ask you to return for a follow-up visit in a couple of weeks to check how your gums are responding to the presence of your veneer and to once again examine the veneer’s placement.
What Are the Advantages of Dental Veneers?
Veneers offer the following advantages:
They provide a natural tooth appearance.
Gum tissue tolerates porcelain well.
Porcelain veneers are stain resistant.
The color of a porcelain veneer can be selected such that it makes dark teeth appear whiter.
Veneers offer a conservative approach to changing a tooth’s color and shape — veneers generally don’t require the extensive shaping prior to the procedure that crowns do, yet offer a stronger, more aesthetic alternative.
What Are the Disadvantages of Dental Veneers?
The downside to dental veneers include:
The process is not reversible.
Veneers are more costly than composite resin bonding.
Veneers are usually not repairable should they chip or crack.
Because enamel has been removed, your tooth may become more sensitive to hot and cold foods and beverages.
Veneers may not exactly match the color of your other teeth. Also, the veneer’s color cannot be altered once in place. If you plan on whitening your teeth, you need to do so before getting veneers.
Though not likely, veneers can dislodge and fall off. To minimize the chance of this occurring, do not bite your nails; chew on pencils, ice, or other hard objects; or otherwise put excessive pressure on your teeth.
Teeth with veneers can still experience decay, possibly necessitating full coverage of the tooth with a crown.
Veneers are not a good choice for individuals with unhealthy teeth (for example, those with decay or active gum disease), weakened teeth (as a result of decay, fracture, large dental fillings), or for those who have an inadequate amount of existing enamel on the tooth surface.
Individuals who clench and grind their teeth are poor candidates for porcelain veneers, as these activities can cause the veneers to crack or chip.
How Long Do Dental Veneers Last?
Veneers generally last between 5 and 10 years. After this time, the veneers would need to be replaced.
Do Dental Veneers Require Special Care?
Dental veneers do not require any special care. Continue to follow good oral hygiene practices including brushing and flossing as you normally would.
Even though porcelain veneers resist stains, your dentist may recommend that you avoid stain-causing foods and beverages (for example, coffee, tea, or red wine).
Are There Alternatives to Dental Veneers?
Yes, alternatives to veneers include bondings and crowns. Veneers offer a nice intermediate option. Veneers may be best suited for individuals who want to change the shape of their teeth more than just a little bit — as is done with bonding — but not enough to require a crown.
How Much Do Veneers Cost?
Costs of veneers vary depending on what part of the country you live in and on the extent of your procedure. Generally, veneers range in cost from $500 to $1,300 per tooth. The cost of veneers is not generally covered by insurance. To be certain, check with your specific dental insurance company.
The First of Many Impressions
Similar to most restorative dental procedures, impressions are taken before, during, and in some cases after the final placement of the veneers. The impressions taken before your veneer appointment are used to make a stone replica of your teeth. The stone cast may be sent to the dental laboratory to assist the lab tech when fabricating the final veneers, or to create a wax-up; replica of what the final veneers will look like. The wax-up may be used to create a temporary set of veneers that is worn during the time when the veneers are being made.
Choosing a Shade
Choosing the shade of the veneers is an exciting step for most people. The final shade is determined by your request for a certain result, along with the dentists recommendations. Customized to your skin tone and overall desire for whiter teeth, your dentist will recommend a shade that he feels will best appear as natural as possible, while still giving you the look of attractive, flawless teeth. It may be necessary for you to visit the dental laboratory that is making your veneers, as they are able to do a very customized shade analysis. Not only are they looking for the best shade for your individual skin tone, they may be trying to match the veneer to the shade of the surrounding teeth. This task is especially important to ensure the natural look of the veneer remains consistent.
Preparing the Teeth
Veneers require very little removal of the enamel surface of the tooth. It will generally depend on the type of veneer used, position of the teeth, or the dentists preferred method of preparing the tooth.
You may or may not require local anesthetic for the appointment. Teeth that have been root canalled or teeth that require very little preparation, may allow you to avoid the need for anesthetic. Your dentist will use the high speed hand piece to contour the front surface of the tooth. Impressions of the prepared teeth are taken inside your mouth using a very precise impression material that starts our as a thick paste. The impression material is filled into a tray and placed on the teeth. The dental assistant will likely hold the impression tray in your mouth until the material sets, usually after 3 to 5 minutes. An impression of how your teeth bite together is also taken. Impression material is applied to the biting surface of the bottom and top teeth. You will be asked to bite down into the material for 1 to 2 minutes until the material is set; depending on the brand used. If the dentist is satisfied with all of the impressions, they are delivered to the dental laboratory.
Temporary Veneers
The dentist or dental assistant will construct a set of temporary veneers made from an acrylic material, that will be cemented onto your teeth with a temporary cement. They will resemble your natural tooth, but may not appear as white as the final set of veneers and may feel rougher than your naturally smooth enamel. These temporary coverings will help protect the teeth from sensitivity, but keep in mind they are just as their name indicates; temporary. You should avoid the following with your temporary veneers:Biting into or chewing hard and food
Gum and sticky candy should be avoided
Using the prepared teeth to open or tear non-food items
Biting your nails
Food or beverage that contains deep pigments that will stain the acrylic.
Biting into or chewing hard and food
Gum and sticky candy should be avoided
Using the prepared teeth to open or tear non-food items
Biting your nails
Food or beverage that contains deep pigments that will stain the acrylic.
Your New Smile
The veneers will return after 7 to 10 business days for final cementation. They will be placed on your teeth without any cement so the dentist can inspect them for any obvious flaws. Your final approval will give the go ahead for the dentist to permanently cemented the veneer to the tooth’s surface with a dental resin.
If you had local anesthetic for the first appointment, it may be necessary for this appointment as the teeth need to be cleaned with water and prepared with a solution called acid etch, that microscopically roughens the surface of the tooth . This is necessary to achieve the best adhesion of cement to your teeth. As mentioned your teeth will be prone to sensitivity and since the correct placement of the veneers is paramount, freezing may be a benefit to both you and the dentist.
The cement is placed on the back of the veneer and then placed onto your tooth. A bright light known as a curing light, may be used to harden the cement. Any excess hardened cement is removed from the teeth.
The dentist will check how your teeth bite together to ensure you re not biting incorrectly onto the veneers. Small reductions of the opposing teeth may be necessary if the bite is not correct.
Caring for Your Veneers
Although veneers are designed to allow you to functioormally, you may want to consider trying not to bite into hard food with your front teeth, or use your teeth to open difficult items, because they may chip or break. Occasional you may have foods and beverages like red wine, tomato sauce, grape juice, and tea or coffee. But keep in mind that the porcelain material can pick up stain from deeper pigmented foods and beverages. And unlike our natural teeth, they cannot be whitened with tooth whitening gels.
Your dentist may recommend the use of a night guard, or splint while sleeping. This will protect your lower teeth from the effects of the porcelain grinding on the enamel. Even if you do not knowingly grind your teeth, porcelain is damaging to enamel during even slight grinding of the teeth. Veneers are designed to last between 10 to 15 years. Regular cleanings from your dental hygienist are still recommended, along with regular dental checkups.
Fundamental principle of diagnostic research in clinical prosthodontics is the study and recognition of the disease to a conclusive diagnosis.
Disease as a violation of vital functions in response to emergency external stimuli or internal environment manifests some common symptoms or signs of a group. Each sign is called a symptom.
There are objective and subjective symptoms.
Subjective symptoms – symptoms that were identified during the survey of the patient (the feelings arising from a period of time and which the patient was not before). Objective symptoms are detected during clinical examination of the patient.
The disease can manifest itself not one but several subjective and objective symptoms, some of which are specific for this disease, while others observed among different diseases. Signs of disease may also be a specific set of symptoms (symptom), called the syndrome. Syndromes differ naturally constancy of occurrence, characterizing certain pathological conditions.
Diagnostic Study provides for the investigation of subjective and objective symptoms, etiology, pathogenesis, clinical picture of disease in a particular patient, his physical and mental health, to establish the degree of morphological and functional nature of the changes that constitute the essence of the disease. Therefore, without knowledge of physiological norms and possible variations of physiological functioning of certain organs, teeth and jaws that make up the system, their topographic and functional relationships difficult to properly formulate a diagnosis and take the necessary therapeutic manipulation.
During the diagnostic investigation of patients in clinical prosthodontics, regardless of the subjective data and of obvious clinical symptoms should be examined zuboschelspna whole system, each of its body, rated the overall body condition, and the clearing and associated the disease, necessity of additional (special) methods.
Habits of medical action in the diagnostic research is focused coherent survey stages: determine the complaints of the patient and study history, objective examination by clinical and special methods (study of morphological changes and functional disorders), establishing the diagnosis (nosological form of the disease) .
Interviews with patients (clarify complaints, history taking).
General registration data about the patient:
1.Surname and name.
2.Age.
3.Place of work.
4.Profession.
5.Adress.
6.First visit to the clinic.
During an interview with a patient trying to find out the reasons for his appeal to the clinic (complaints, subjective feeling), the first signs of illness (illness history), health and living conditions (life history).
During the conversation, it is important to establish contact with patients, try to understand him as a person and gain confidence. You should therefore pay particular attention to the specific patient presenting complaints.
1. The reasons for the appeal to the clinic (patient complaints).
At the beginning of the conversation, the patient explains the causes and nature of those unusual sensations (subjective symptoms) that its concerns. Depending on the pathology of patients may complain of:
• difficulty in chewing food due to lack some or all of the lateral teeth;
• inability to nibble food due to lack teeth;
• stertist or mobility of teeth;
• difficulty opening the mouth.
• Pain in the gums, mucous membrane, temporomandibular joint, bleeding gums;
• burning sensation in the tongue and taste;
• breach of taste;
• Bad breath;
• fix bad dentures;
• denture base fracture;
• discoloration of the combined fixed structures;
• aesthetic defect
2.Anamnesis existing illness.
It should be noted early signs of disease (when, how and under the influence of reason, according to the patient, the disease began), as developed prior to appeal to the clinic (nature and characteristics of its course), or apply some treatment (type and amount), which was its effectiveness (or the patient meets the prosthesis, and if not, the reasons).
Clinical examination methods:
External review and inspection of the face:
External review of the face, despite the communist considerations should be imperceptible to the patient during a call. During the survey study anatomical, morphological and functional features of the face.
· type of face;
· vertical size of the lower face;
· condition of skin of face and neck;
· ratio of upper and lower lip;
· the position of angles of the mouth;
· The degree of baring the teeth while smiling and talking
· the degree of opening the mouth;
Oral examination:
Assessment of teeth:
• position of each tooth, its shape, color;
• The state of the coronal hard tissue (presence of fillings and artificial crowns);
• Tooth mobility;
The dental examination conduct with: dental mirror, tweezers, dental probe. Application of mirrors allows inspect each tooth on all sides, using tweezersdetermine mobility of teeth, the probe is used to establish whole surface of the tooth crowns, tooth sensitivity plots, deep of periodontal pocket.
