After objective research, analysis and clinical diagnosis, a final decision on the choice of prosthesis design is made. The choice of a given prosthesis depends not only on the nature of the disease, but also the stage of pathological process. For example, when a small lesion of dental hard tissues by caries the defect replacement with a filling is adequate y. With more considerable destruction of dentin enamel an insert is more appropriate.If the tooth defect caot be restored with an insert or a filling, a full prosthetic crown is prescribed, that means orthopedic therapy is chosen with consideration of the pathological process and it is one of the conditions for successful orthopedic treatment.
Production of any denture consists of performing certain clinical and laboratory stages.
Clinical stages are performed by a doctor and include initial review of the patient, analysis of clinical examination, diagnosis, choice of prosthesis design and clinical stages of its production.
Laboratory stages are carried out in laboratories by a dental technician and include various technological stages of production, depending on the type of prosthesis made.
Clinical-laboratory stages of making inserts
1. Clinical:
а) Forming cavity and insert modeling (direct method);
б) Forming cavity and obtaining impression (indirect method).
2. Laboratory:
а) Replacemen to wax structure to metal one(direct method);
б)Modeling from wax and replacement to metal (indirect method).
3. Clinical:
– Insert fitting.
4. Laboratory:
– Insert grinding and polishing.
5. Clinical:
– Insert fixing.
Methods of making inserts
There are several ways of obtaining an insert wax model : direct, indirect (overhead) and combined. In direct mode an insert is modeled from wax directly in the mouth. Tooth is covered with cotton rollers, a bottom and walls are moistened with water. Then a stick of modeling wax is taken and heated over a flame burner till the moment when the wax becomes plastic. A small wax taper is formed and while the wax is plastic, it is pressed with hands or a spatula in the formed cavity. Excess of wax is gently removed from the surface, and while plasticity is present, the patient is asked to close teeth in the position of central occlusion, and then play the chewing motion.
The insert surfaces at the same time takes the form characteristic for functional occlusion. Further modeling is aimed at restoring the anatomical shape of the tooth destroyed, focusing on the teeth of the other half of the jaw. Insert wax model edge should overlap the edge of the cavity (this helps to avoid insert shortening during casting and adjusting). During insert manufacture ieck cavity, simulating its edge is modeled to the level with the surrounding tooth hard tissues. For the extraction of insert model posts made from orthodontic wire are used(0.8-1mm x 1.5-
Indications and advantages of direct method
Indicationsforusageofdirectmethodforobtaininginsertwaxmodel(G. V. Bezvisnih, 1988) arerestorationofteethwithchewingornecksurfacedefect,as well as modeling of artificial stump crown with a post.
Advantagesofdirectmethod.
1. Outstandsinbetteraccuracy, becausethereisnoneedtoobtainimpressionandmakeworkingplastermodel, whichdiffersinvolumechangesofimpressionandmodelingmaterials..
2. Insertmodelingonanaturaltoothinthemouthgivesanopportunitytoconsiderfunctional.
3. Anopportunitytocontrolinsertbordersnotonlyoncavityedgesbutalsoingumareazone, whichisimportantforpreventionoftraumaticperiodontitis.
Disadvantages of direct method
1. Tired state of the patient, as the manipulation is sufficiently long.
2. Risk of burning the oral mucosa with hot modeling tool or wax.
3. The complexity of modeling the insert into the interdental spaces (cavity II, III, IV classes by Black).
4. Dentist’s irrational spending on performance of technical procedure.
5. The need for special training in medical theory and practice, simulation, continuous training of its performance in this difficult clinical acceptance for the support of manipulative skills at a high enough level.
6. The need for re-modeling the insert in the mouth in case of deformation in the derivation or unsuccessful casting.
7. Inabilityof preadjusting of an insert on the working plaster model that extends its adjustment time in the mouth.
8.Inability to use methods of metal shrinkage compensation during casting (selective coating with insulating paint of the walls and bottom of the model cavity), providing space for placement of cement.
9. Dismemberment of obtaining wax insert models on several stages at large amount of removed teeth. Indirect way of making insert.
After the cavity has been formed the doctor obtains an impression. It must be of high precision. This is achieved by a double or combined impression. For combined impression after cavity preparation an impression is obtained with silicon material and a copper ring is prepared according to cast plaster model. Ready ring is checked on an abutment tooth. It has to cover its equator tightly, and go down to the neck on the interdental spaces of the cavity. Filled with heated flexible termomass ring is put on the tooth , and a general impression is taken from all dentition with impression material. Impressions are removed in reverse order, then to the general impression a ring with termomass is put. A combined dismountable model is cast, where an insert is modeled. Currently this method is rarely used.
Dental Inlays & Onlays: Differences, Procedure
Dental inlays and onlays are a dental procedure that is used to restore a decayed or damaged tooth to its original condition and can actually strengthen it. They are a more conservative approach than a dental crown because they don’t involve the removal of healthy tooth structure. For this reason inlays and onlays are considered a minimally invasive cosmetic dentistry treatment and for many dentists and patients is a much better choice. A crown, although not a bad procedure, involves the removal of more healthy tooth structure thaeeded and can increase the risk of tooth fracture and the need for a root canal treatment.
Inlays and onlays are fabricated in a dental lab and are then fitted and bonded to the damaged tooth by the dentist. This type of restoration is called an indirect filling because unlike a traditional dental filling they are not molded into place during your dental visit.
What is the Difference Between an Inlay & Onlay?
Both inlays and onlays are pre-formed in a lab before being bonded to the damaged or decayed tooth. The difference of use depends on the amount of tooth structure that has been lost to wear or decay. Your dentist will help you decide which is most appropriate for you.
An inlay fits within the grooves that are within the cusps of your teeth. An onlay, the larger of the two, fits within the grooves but wraps up and over the cusps covering more of the tooth’s surface. An onlay is used when the damage is more extensive and the restoration covers the entire chewing surface including one or more tooth cusps.
The Inlay/Onlay Procedure
The procedure to place an inlay or onlay is basically the same and both require two dental visits unless your dentist has an in-office milling unit The first dental visit will involve the preparation of the tooth which includes the removal of the decayed or damaged portion. Because the procedure is conservative, the dentist will only remove as little tooth structure as possible to restore your tooth. The area is numbed by a local anesthetic before being removed by a drill, dental laser or air-abrasion device.
The single visit restorations are typically made by a machine such as the CEREC that enables the dentist to make porcelain crowns and inlays/onlays quickly and bond them in a single appointment. Inlays and onlays can also be made from gold or resin materials which each have their own advantages. Gold has often been considered the strongest option although is not the most esthetic. You can discuss with your dentist what they think is the best option for you.
The permanent restoration involves the cleaning of the tooth to prepare for the new inlay or onlay. The inlay or onlay will be placed to ensure a correct fit before it is bonded to the tooth. If the fit doesn’t interfere with the patient’s bite, it is permanently attached to the tooth using special cement or bonding then polished for appearance.
To repair damage to the tooth’s biting surface, rather than using a simple filling, or a crown, a dentist will often use an inlay, or an onlay. Inlays and onlays can be made from porcelain, gold, or composite or ceramic resin, although porcelain is now becoming the material of choice because of its strength and potential to match the natural color of your tooth.
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An inlay is similar to a filling and lies inside the cusp tips of the tooth. They are custom-made to fit the prepared cavity and are then cemented into place. An onlay is a more extensive reconstruction that covers one or more cusps of a tooth. Onlays are indicated in situations where a substantial reconstruction is required. However, more of the tooth structure can be conserved compared to the placement of a crown. Inlays and onlays are applied in two dental visits. At the first visit, the old filling, or decay, is removed, and the tooth is prepared for the inlay / onlay. The dentist will then make an impression of the tooth, and send this impression to a dental laboratory. This impression will be used by the laboratory to construct a custom-made porcelain, or gold inlay / onlay. At this time the dentist will place a temporary sealant on your tooth and schedule a second appointment. |
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At the second visit, the temporary sealant is removed. Your dentist will then ensure that the inlay / onlay fits properly in the tooth and does not interfere with your bite. The inlay / onlay is then bonded into the tooth with a strong bonding resin, and polished smooth.
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An insert is like a refined version of the seal teeth. This microdenture is of high strength, which is fixed in the cavity with cement. The main difference of an insert from a seal that during seal manufacture the material itself must be fixed to tooth hard tissues and at the same time have very high strength. An insert is only modeled in the oral cavity, and the formation of an insert from metal or plastic is done out of the mouth, which allows to achieve high strength, and during fixing an insert is retained in the cavity, not only by its own retention, but also because of the properties of fixation cements.
There are several ways of obtaining an insert wax model : direct, indirect (overhead) and combined. In direct mode an insert is modeled from wax directly in the mouth. Tooth is covered with cotton rollers, a bottom and walls are moistened with water. Then a stick of modeling wax is taken and heated over a flame burner till the moment when the wax becomes plastic. A small wax taper is formed and while the wax is plastic, it is pressed with hands or a spatula in the formed cavity. Excess of wax is gently removed from the surface, and while plasticity is present, the patient is asked to close teeth in the position of central occlusion, and then play the chewing motion.
The insert surfaces at the same time takes the form characteristic for functional occlusion. Further modeling is aimed at restoring the anatomical shape of the tooth destroyed, focusing on the teeth of the other half of the jaw. Insert wax model edge should overlap the edge of the cavity (this helps to avoid insert shortening during casting and adjusting). During insert manufacture ieck cavity, simulating its edge is modeled to the level with the surrounding tooth hard tissues. For the extraction of insert model posts made from orthodontic wire are used(0.8-1mm x 1.5-
Contraindications to insert manufacture are:
· Thin walls of the tooth surrounding the cavity – an insert can break off these walls;
· Small cavity in the tooth – an insert requires additional preparation.
So, as a direct method of insert manufacturing runs without a dental technician, we do not give the materials on this method in the guideline.
Clinical-laboratory stages of making insert by direct and indirect method from metal.
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CLINICAL |
LABORATORY |
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1. Anesthetization. Preparation of tooth canal and cavity. Obtaining bilayer impression (it is obtained by special way with reflection of tooth cavity and canal) from working jaw, additional impression иocclusive impression. Occlusive impression is better obtained with silicon. |
1. Casting dismountable combined model. 2. Makingwaxcomposition 3. Replacementwaxonmetal 4. Structure processing and polishing. |
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II. Adjustment stump crown insert in mouth, fixing on cement. |
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When receiving an impression and model casting technician assesses the prepared cavity. It must meet the following criteria:
• The vertical walls of the cavity must be mutually parallel and slightly divergent.
• The bottom of the cavity must be parallel to the roof of the pulp chamber.
• Fold must be made along the edges of the cavity , ie, enamel edges are cut off at an angle 45 degrees with respect to the cavity.
If the cavity meets these criteria, the bottom of the model cavity is covered with one or two coats of compensation varnish. Then an insert modeling from a soft wax is started. To this effect wax is softened in a water bath, rolled in a columns with a diameter slightly smaller than the cavity of a tooth. The bar of wax under pressure is introduced into the prepared cavity. Excess wax is cut with the modeling spatula, and chewing surface in modeled taking into account the anatomical features of the surface of the tooth. Modeling should be conducted only in occludor and occlusal contact must be constantly monitored. Modeled wax composition is removed from the cavity with one or more posts that are stuck to the already stiff insert.
Metal inserts are cast from different alloys used in dentistry. More accurate, and indifferent to the tissues of the mouth are the inserts from precious metals – gold or silver 750.
The main drawback of these inserts is their not cosmetic view. That is why in the last 10-20 years the most popular materials for insert manufacture are ultrastrong plastics.
Clinical-laboratory stages of making porcelain insert.
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CLINICAL |
LABORATORY |
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1. Anesthetization. Preparation of tooth canal and cavity. Obtaining bilayer impression (it is obtained by special way with reflection of tooth cavity and canal) from working jaw, additional impression иocclusive impression. Occlusive impression is better obtained with silicon. |
1. Casting refractory model 2. Special preparation of cavity on a model. 3. Plasticlayerwise putting 4. Polymerization. 5. Processing and polishing. |
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II. Adjustment stump crown insert in mouth, fixing on cement. |
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Inserts from porcelain are used to restore the defects of crowns, as for the front and side teeth. To use porcelain inserts indications should be clearly defined . Several different preparation of hard tissue prosthetic bed: depth cavity must be at least half the width. It should be noted that when planning a porcelain insert enamel slant (fold) must not be made due to the fragility of china. In the manufacture of porcelain insert certain laboratory technology is used, and the insert is prepared indirectly. After obtaining bilayer impression a refractory model is received, where layer by layer porcelain masses , taking into account the volume shrinkage are applied. Originally ground layer of the porcelain mass is applied on the cavity bottom and wall, and after firing a frame is received. Then the remaining layers of porcelain mass are put and fired till the prosthesis is ready.
Inserts of porcelain are much stronger than the hard tooth structure, more aesthetic than plastic ones. In addition, they do not cause allergic reactions and no adverse effects on oral tissues.
nlays and Onlays
Inlays-Class I and II
Indications
1. Mostly elective on the part of a patient.
2. Used to complement treatment when gold and/or ceramics are the dominant choices for restorations.
3. When form and function are most reliably restored with a casting. For example, it is not advisable to change existing tooth contour by placing an amalgam restoration.
4. Occasional rest seat for a removable partial denture clasp.
The following factors deserve attention when considering Class I and II inlays: (1) the age of the patient, (2) the degree of caries activity, and (3) economics of treatment.
If a Class I lesion exists, the interproximal area must be carefully analyzed for possible weakness before considering a one-surface inlay. If it appears that the interproximal area is suspect as related to caries activity, an occlusal inlay is not indicated. When a two-surface casting is designated as part of restorative treatment, either as an MO or DO, the remaining proximal surface must be examined carefully and a determination made that caries is not a factor for that surface (Fig. 15-2).
At a time when Class I and II inlay preparations are the most needed, the cost to the patient is the greatest problem. The budgets of most families have difficulty with a treatment plan emphasizing gold when other options are available.
In spite of the precautions stated, a Class II inlay that is skillfully accomplished, with good margins and anatomy, is a picturesque and a very functional restoration. The knowledge and ability to prepare Class II castings is basic to the cast restoration and its fundamentals should be clearly understood and executed during treatment, as this is one of the classic backgrounds for restorative treatment.
Inlay Preparation-Class I
Procedure
The rubber dam can be used easily with a washed field procedure, and its use is advised for the preparation of inlays. As for other operations, the rubber dam is very helpful for isolating the area. It is a great aid to visibility and for partial retraction of the gingival tissue. It is the best way to prevent debris from the preparation from being swallowed or aspirated.
The design requirements for an inlay preparation must allow for the convenience of placing the cast restoration. There must be assurance that when the inlay has been placed the margins will be closed to prevent leakage.
The occlusal walls must be tapered from the pulpal wall to allow the withdrawal of the pattern or casting in an occlusal direction. All occlusal walls are tapered from the pulpal wall toward the occlusal opening.
As a relative guide the pulpal wall will develop on dentin using a No. 170 or 171 bur just beyond the dento-enamel junction. When a bur is cutting at high speed, it is recommended that a water spray be directed on the cutting instrument. The spray in turn is removed by using a high-velocity vacuum system.
All major grooves are followed to clear any existing or potential defect. The outline is a series of coordinated and connecting curves. The buccal to lingual extension will exceed that required for an amalgam to allow for convenience and an adequate line of withdrawal. The pulpal wall is expected to be flat throughout the preparation.
When preparing a Class I preparation, special precautions are observed when approaching the mesial and distal marginal ridges. It is important that these functional ridges be left intact and not in a weakened state. The angulation of the mesial and distal walls is important as a means of preserving the marginal ridges.
When occlusal caries invades, undermines, and weakens any of the cusps, the outline of the preparation must be extended to terminate in enamel that has good dentin support. Frequently, the occlusal caries of lower molars extends into the buccal groove, which then should be included in the preparation outline. If this is required, the occlusal groove is terminated on the buccal surface with the same No. 170 bur.
When caries penetration extends beyond the normal depth required for the preparation and is a cause of pulpal distress, a base is indicated. Without concern for the penetration of the caries the preparation is positioned at its ideal depth location. Also, enamel that has no support is cut away. At the conclusion of this portion of the preparation the remaining caries is removed and treated as discussed in Chapters 6 and 7. Burs at slow speed and hand instruments are used to produce a smooth surface for the base and the preparation.
Inlay Preparation-Class II
Procedure
The initial portion of the Class II preparation is the development of the occlusal segment. The occlusal outline and location of the pulpal wall are the same as for the Class I inlay preparation.
Proximal Box. As the outline and form of the occlusal segment are completed the next step is to enter the proximal portion and begin developing the box form. The occlusal preparation is extended proximally into the marginal ridge, but a thin portion of the marginal ridge is left intact. A No. 69 bur is used to begin the proximal box and it penetrates gingivally with the dento-enamel junction as a guide. The gingival extension is made by cutting both enamel and dentin; if the penetration is done totally at the expense of the dentin, the axial wall might be too close to the pulp.
The proximal box must be positioned gingivally to break contact with the adjacent tooth. It must proceed beyond defective enamel. If the gingival tissue is in a normal position, this will often place the gingival margin within the gingival sulcus. If gingival recession has occurred, there is no attempt to move the gingival wall into the sulcus except as required by the extent of caries.
With most teeth the gingival wall will be positioned at right angles to the long axis of the tooth. The buccal and lingual walls are extended just beyond contact with the adjacent tooth. When this is being done, care must be exercised to avoid tendency toward placing undercuts in any of the walls. The buccal and lingual extension should not be completed by using burs. This would result in overextension of the walls or possible damage to the adjacent tooth
Hand instruments are used for final location of proximal walls and margins. The walls and margins must be located to include all defective or weakened tooth structure. The proximal margins must be located so as to conveniently finish the metal-to-enamel interface. This is not a major problem, for even with demanding esthetic criteria most margins may be placed and allow for reasonable finishing convenience
The final design and internal detail of the preparation are obtained using sharp hand instruments. The usual preference is to use enamel hatchets for the lower teeth and bin-angle chisels for the upper teeth. All walls and margins must be smooth and precise following instrumentation. Special emphasis is given to the cavosurface margin to guarantee there will be no loose or irregular enamel remaining. When access permits, it is possible to use cuttle or sandpaper disks to place the final touch on the margins.
Gingival Bevels. The gingival wall will have a definite cavosurface bevel. This bevel is required to remove enamel rods that have poor support at this location and also to provide a decrease in the potential opening or discrepancy of fit between the casting and the tooth. This potential discrepancy exists because it is difficult to make a casting that accurately fits the prepared tooth. If poorly supported enamel is left, it may fracture during or following placement of the casting, leaving defects in the gingival area that would encourage recurrent caries. If there is no bevel and the casting does not seat completely, the resultant discrepancy extends to the axial.
Placing an adequate gingival bevel will reduce the magnitude of this discrepancy. The bevel should be approximately
Toplace the proper bevels one of several instrumentations may be used. A flame-tipped diamond operating at reduced speed will produce a good bevel form. It may tend to overcut if operated at high speed. Carbide finishing burs, also with a flame-tipped design, will do the same thing and leave a smoother surface than most diamonds. Hand instruments are effective for placing these bevels on interproximal gingival walls. The gingival margin trimmer or angle former is used for this purpose, and the former is effective with either upper or lower teeth; because of access problems the latter is limited to use with maxillary bicuspids. The best control is maintained by choosing the medium sized or larger instruments. It is important that when these instruments are sharpened the initial blade angle be maintained.
The finish of the enamel walls is accomplished with the same plain fissure bur as used for the preparation. This type of bur is used near its stall-out speed for finishing purposes; otherwise the preparation will be overcut. Enamel finishing burs with 12 or more blades may also be used to smooth the enamel. As a result of the angulation of the occlusal walls, it is not required to provide a cavosurface bevel to the occlusal margins. A soft casting gold may be used for small preparations, which simplifies adaptation of the metal margins .
Pivot crowns.
Stump insert
The main difference between these structures is the fact that this design is unique in prosthodontics, which is its main part in the root canal. This part of the structure and is called the post.
At first let us analyze the transitional form between an insert and pivot crown – the so-called stump insert, which, after fixation is covered with various crowns. The system, consisting of two independent parts (cast post insert and a crown covering it ), has several advantages over all types of pivot crown teeth and a simple insert, because it is always possible to replace covering structure without violation of fixation integrity of cast post insert.
Indications for usage of cast post inserts:
1) significant defects in dental crowns as a result of tooth decay or injury,
2) pathological abrasion of tooth hard tissue,
3) anomalies of the anterior teeth in adults;
Contraindications for usage of cast post inserts:
1) Tooth mobilityIII,
2) insufficient length of the tooth root to form a complete post insert ,
3) teeth have previously undergone resection of the tips of roots,
4) teeth with curved roots and impassable canals.
Clinical-laboratory stages of making stump crown insert by indirect method
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CLINICAL |
LABORATORY |
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1. Preparation of tooth canal and cavity. Obtaining bilayer impression (it is obtained by special way with reflection of tooth cavity and canal) from working jaw, additional impression иocclusive impression. Occlusiveimpressionisbetterobtainedwithsilicon. |
1) Casting dismountable model. 2) Modelinginsertfromwax. 3) Obtaining insert from wax. 4) Replacementwaxtometal. 5) Grinding insert. |
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II. Adjustment stump crown insert in mouth, fixing on cement. |
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During preparing the tooth root canal of the doctor takes into account the thickness of its walls. After the expansion of the channel in the mouth the doctor creates a so-called elliptical cavity depreciation in the vestibular-oral direction depth of 2.5-
Canal expands to the diameter of 1-
After the preparation of dental hard tissues a bilayer silicone impression is obtained. When obtaining the impression with a special post or canal-filler the doctor “drives in” corrective mass into the tooth root canal and thus gets the impression of the tooth root.
Combined dismountable model is prepared in the usual way. The surface of the tooth cavity and channel is smeared with compensation varnish.When the model is ready cast post insert modeling is started. For this purpose special wax is used. Typically, waxes for stump inserts are in the form of elongated flat sticks. A stick of wax is warmed, pulling it until its thickness is thinner the diameter of the entrance to the channel. Stick is entered to the model channel with slight pressure. Excess wax is cut at the level of the occlusal surface. Then it is proceed to the modeling insert overroot part. It is shaped into a truncated cone. Interocclusal distance that is formed depending on the structure, which will cover the stump insert.
After completing modeling in the thickness of the sump part of the wax composition along the tooth axis at 1-
Modeling cast post inserts at abnormalities of the teeth is different. With a view to aesthetic layout nonremovable prosthesis in the dental arch the stump part of the post insert is modeled, slightly modifying the topography of the stump. In this case one must consider the action of functional forces and know, that the inclination of the stump part to the axis of the tooth must not exceed 15 °.
With proper preparation of the abutment tooth and the observance of the laboratory technology of casting metal insert should be freely entered into the root canal and fit snugly to the hard tissues of the abutment tooth.
After adjustment it is necessary to grind roughness on insert stump off. To conduct grinding or other interventions on insert post part is unacceptable.
TYPES OF DENTAL INLAYS AND DENTAL ONLAYS
There are two types of dental inlays and onlays:
: Tooth-Colored Inlays and Onlays
Several types of tooth-colored inlays and onlays have been developed primarily for use in larger defects in back teeth. These are used in place of a crown (cap) or filling (restoration). They are made of porcelain, other ceramics, or resin (plastic). These materials are made in a laboratory and are cemented into place using a liquid plastic form of cement. Two appointments are required for their completion. These are beautiful restorations, matching tooth structure nearly exactly, but they have not been used long enough for optimal research knowledge about their long-term characteristics.
For nearly a century, cast gold inlays and onlays have been regarded by many dentists as the best, longest-lasting method to repair teeth. Inlays fit within the biting surface of the tooth, whereas onlays cover the top of the biting surface. Many of these restorations serve for most of a patient’s lifetime. However, they are difficult to accomplish, expensive, and highly demanding of the dentist’s skill.
THE PROCEDURE OF DENTAL INLAYS AND DENTAL ONLAYS
Two appointments of approximately one to two hours per tooth.
ADVANTAGES & DISADVANTAGE OF DENTAL INLAYS AND DENTAL ONLAYS
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Advantages : · Highly esthetic · No metal shows · Strong once bonded to tooth · Well-sealed tooth · Will not stain · Will insulate the tooth · Well suited for large cavities · Long lasting |
Disadvantages : · More costly than amalgam or composite · Can fracture · Takes two appointments |
ADVANTAGES & DISADVANTAGE OF DENTAL INLAYS AND DENTAL ONLAYS
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Advantages : · These restorations may be designed to add strength to weakened teeth by covering weakened portions of teeth. Gold alloys used in dentistry may be designed to wear nearly exactly the way opposing natural tooth enamel wears. This advantage is significant, because opposing teeth are not worn away rapidly. High-quality cast gold restorations have a long service potential. |
Disadvantages : · Because of the necessity to make the gold inlay or onlay outside of the mouth in a laboratory, two appointments are necessary. The tooth must first be prepared (trimmed) to remove the decay or old restoration, to allow the inlay or onlay to be placed into or onto the tooth; at a second appointment the restoration is cemented into place. These restorations require significant shaping and cutting of the tooth. Therefore, gold alloy restorations are not as conservative as silver amalgam restorations. Gold alloys are gold in color and are not acceptable to most people in areas of the mouth where they are visible. Their use is generally limited to back teeth. |
After
PATIENT MAINTENANCE
Avoid biting hard objects in order not to fracture the porcelain. Normal brushing and flossing. Use fluoride mouth rinse and toothpaste as prescribed by your dentist. Same dietary restriction (as above) for the longest restorative life.
Tooth sensitivity, short or long term, may be present in a few of these restorations. If tooth sensitivity persists, endodontics (root canal therapy) may be necessary, but this is infrequent. Some tooth-colored restorations break during service because they are not as strong as those made of metal. If breakage occurs, the restoration can be remade. Because these restorations have not been used as long as metallic restorations for back teeth, knowledge about long-term service is not complete.
For back teeth, metallic restorations are the major alternatives. Silver amalgam and cast gold restorations are strong, acceptable alternatives but are not as pleasing in appearance.
Usually, these restorations require two appointments and some relatively complex laboratory work. The necessary expertise and effort requires a cost that is near or equal to that of cast gold restorations, or about five to eight times more than composite restorations.
Porcelain inlays/onlays can successfully achieve both esthetic and functional results in restoring discolored or metal posterior teeth. More conservative than full crown.
BEFORE & AFTER OF DENTAL INLAYS AND DENTAL ONLAYS
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Dental Inlays
Dental inlays are used by dentists to repair the damage to the biting surface of the tooth. A dental inlay is used to repair the damage caused by tooth decay or any other reason to the indented top surfaces of the teeth; dental inlays onlays can also be used to replace damaged or old metal fillings on teeth, with the application procedure usually carried out over the course of two dental appointments.
This is Dentistry recognizes the importance of having detailed information on dental inlays, because we know that you need to have all the information you can get your hands on before undergoing any dental procedure or treatment. This is Dentistry also gives you access to the contact information of dentists in your local area, who can give you the answers you need regarding dental inlays onlays.
A dental inlay can repair the damage done to a tooth by tooth decay, and it can also stop tooth decay and cavities from further spreading to other parts of the tooth. Dental inlays onlays are considered as indirect fillings, and are customized in a laboratory prior to being applied to the patient’s tooth. Dental inlays require less tooth structure to be removed, and can last for a longer period of time compared to dental fillings.
Dental Inlay Procedure
After removing the part of the tooth that has been damage by tooth decay, your dentist will get an impression of the tooth that needs to be restored with the dental inlay, and the impression will then be sent to the laboratory where it will be customized using the dental inlay material you have chosen. Most dental inlays are made of porcelain (because of the material’s durability and appearance that closely resembles natural teeth), although some people prefer a dental gold inlay. A temporary inlay can be put in place after your first dental appointment, which would then be replaced by the permanent dental inlay on your second visit.
A lot of patients prefer dental inlays onlays because there is very little discomfort or pain felt during and after the procedure. The dental inlays procedure will also not interfere with a patient’s schedule, since there is no downtime needed for the dental inlays to heal – the patient can go on with his regular activities right after having the dental inlays procedure.
Procedure of Inlay and Onlay
The dental procedure for inlays and onlays is one and the same. Both of them require two visit to your cosmetic dentist’s office. The initial visit is one where the dentist prepares the damaged tooth structures by removing all bacteria or caries and cleaning the remaining portions of the tooth. An impression is then taken of the tooth (sometimes accompanied by a digital photo or x-ray) and then is submitted to a qualified dental lab for custom fabrication of the inlay or onlay. The patient’s tooth is filled with a temporary filling material, which is removed once the customized inlay or onlay is seated.
The second appointment usually occurs within two weeks of the initial visit. This final appointment consists of seating the laboratory-crafted inlay or onlay into the affected tooth. First, the temporary filling material is removed, then the tooth is cleaned and finally the inlay or onlay is bonded to the existing tooth structure. Cosmetic dentists generally need to adjust the patient’s bite to ensure that the inlay or onlay fits and functions well when the patient bites down. All points of contact with adjacent teeth are checked and the inlay or onlay is polished to a smooth enamel-like finish.
The inserts are divided by the material of manufacture: metal, porcelain, plastic and composite (metal-ceramic, plastic),by the method of manufacture – made by the direct method (simulation carried out in the mouth of the patient) and made indirectly (under the simulated model).
An insert is like a refined version of the seal teeth. This microdenture is of high strength, which is fixed in the cavity with cement. The main difference of an insert from a seal that during seal manufacture the material itself must be fixed to tooth hard tissues and at the same time have very high strength. An insert is only modeled in the oral cavity, and the formation of an insert from metal or plastic is done out of the mouth, which allows to achieve high strength, and during fixing an insert is retained in the cavity, not only by its own retention, but also because of the properties of fixation cements.
There are several ways of obtaining an insert wax model : direct, indirect (overhead) and combined. In direct mode an insert is modeled from wax directly in the mouth. Tooth is covered with cotton rollers, a bottom and walls are moistened with water. Then a stick of modeling wax is taken and heated over a flame burner till the moment when the wax becomes plastic. A small wax taper is formed and while the wax is plastic, it is pressed with hands or a spatula in the formed cavity. Excess of wax is gently removed from the surface, and while plasticity is present, the patient is asked to close teeth in the position of central occlusion, and then play the chewing motion.
The insert surfaces at the same time takes the form characteristic for functional occlusion. Further modeling is aimed at restoring the anatomical shape of the tooth destroyed, focusing on the teeth of the other half of the jaw. Insert wax model edge should overlap the edge of the cavity (this helps to avoid insert shortening during casting and adjusting). During insert manufacture ieck cavity, simulating its edge is modeled to the level with the surrounding tooth hard tissues. For the extraction of insert model posts made from orthodontic wire are used(0.8-1mm x 1.5-
Materials used in the procedure of inlays and onlays of cosmetic dentistry
In order to ensure their longevity during rigorous daily wear and tear, the material composition of inlays and onlays should be durable and superior. Cosmetic dentists generally like dental laboratories to use are either porcelain or resin; these materials are custom fabricated to match the patient’s tooth enamel color.
Another material used to make inlay or onlay restorations is gold. Gold is most often used on molars in the posterior (back) portions of the mouth, as the color distinction makes the inlay or onlay very visible to the eye.
For visible sight lines, porcelain offers the best esthetic choice. With restorations in the smile line (the areas of the mouth that are visible when a patient smiles), the goal is to match the patient’s tooth color. Often times, patients will bleach their teeth before the inlay or onlay process has begun in order to have the ideal inlay/onlay color.
Resin is a great alternative for patients who grind or clench their teeth. This material is also helpful when used on patients with bite concerns such as malocclusion (a misalignment of the bite).
As more and more cosmetic dentists utilize inlays and onlays, the material make-up of these restorations has improved dramatically over time and as a result, grown stronger and more durable. Cosmetic Dentists review options with their patients before proceeding in order to determine the most appropriate material for the given restoration. Dentists usually send their laboratories copious notes and digitized images to ensure the fabrication process is successful. In addition, cosmetic dentist will often communicate verbally with their dental lab professionals regarding the design of individual inlay or onlay cases. These tiny restorations are handcrafted and require a tremendous amount of skill when being sculpted. Therefore, both the dental lab and the dentist must be qualified professionals who enjoy a superior level of precision in their work.
The inserts are divided by the material of manufacture: metal, porcelain, plastic and composite (metal-ceramic, plastic),by the method of manufacture – made by the direct method (simulation carried out in the mouth of the patient) and made indirectly (under the simulated model).
An insert is like a refined version of the seal teeth. This microdenture is of high strength, which is fixed in the cavity with cement. The main difference of an insert from a seal that during seal manufacture the material itself must be fixed to tooth hard tissues and at the same time have very high strength. An insert is only modeled in the oral cavity, and the formation of an insert from metal or plastic is done out of the mouth, which allows to achieve high strength, and during fixing an insert is retained in the cavity, not only by its own retention, but also because of the properties of fixation cements.
There are several ways of obtaining an insert wax model : direct, indirect (overhead) and combined. In direct mode an insert is modeled from wax directly in the mouth. Tooth is covered with cotton rollers, a bottom and walls are moistened with water. Then a stick of modeling wax is taken and heated over a flame burner till the moment when the wax becomes plastic. A small wax taper is formed and while the wax is plastic, it is pressed with hands or a spatula in the formed cavity. Excess of wax is gently removed from the surface, and while plasticity is present, the patient is asked to close teeth in the position of central occlusion, and then play the chewing motion.
In dentistry, an inlay is an indirect restoration (filling) consisting of a solid substance (as gold or porcelain) fitted to a cavity in a tooth and cemented into place An onlay is the same as an inlay, except that it extends to replace a cusp. Crowns are onlays which completely cover all surfaces of a tooth.
MAKING IMPRESSION
An impression of preparation for restoration with a DO gold inlay on tooth #5. The “DO” designation indicates that the gold serves as a restoration for the distal and occlusal surfaces of the tooth. This tooth was prepared and the inlay will be fabricated according to the R.V. Tucker method of gold inlay preparation. Notice how the line angles of the impression for the inlay are very sharp and precise; this is achieved using carbon-tipped stainless steel instruments. The salmon-colored polyvinylsiloxane impression material is less viscous than the blue and is able to capture better detail for the tooth being restored.
Sometimes, a tooth is planned to be restored with an intracoronal restoration, but the decay or fracture is so extensive that a direct restoration, such as amalgam or composite, would compromise the structural integrity of the restored tooth or provide substandard opposition to occlusal (i.e., biting) forces. In such situations, an indirect gold or porcelain inlay restoration may be indicated. When an inlay is used, the tooth-to-restoration margin may be finished and polished to such a super-fine line of contact that recurrent decay will be all but impossible. While these restorations might be ten times the price of direct restorations, the superiority of an inlay in terms of resistance to occlusal forces, protection against recurrent decay, precision of fabrication, marginal integrity, proper contouring for gingival (tissue) health, and ease of cleansing offers an excellent alternative to the direct restoration.
An MO gold inlay on tooth #3, the “MO” designation indicating that the gold serves as a restoration for the mesial and occlusal surfaces of the tooth. This tooth was also restored according to the R.V. Tucker method. Notice how the gold appears to flow into the tooth structure, almost perfectly mimicking the natural contours and even allowing the specular reflection to continue over the margin from tooth to gold.
Onlays
When decay or fracture incorporate areas of a tooth that make amalgam or composite restorations inadequate, such as cuspal fracture or remaining tooth structure that undermines perimeter walls of a tooth, an onlay might be indicated. Similar to an inlay, an onlay is an indirect restoration which incorporates a cusp or cusps by covering or onlaying the missing cusps. All of the benefits of an inlay are present in the onlay restoration. The onlay allows for conservation of tooth structure when the only alternative is to totally eliminate cusps and perimeter walls for restoration with a crown. Just as inlays, onlays are fabricated outside of the mouth and are typically made out of gold or porcelain. Gold restorations have been around for many years and have an excellent track record. In recent years, newer types of porcelains have been developed that seem to rival the longevity of gold. If the onlay or inlay is made in a dental laboratory, a temporary is fabricated while the restoration is custom-made for the patient. A return visit is then required to fit the final prosthesis. Inlays and onlays may also be fabricated out of porcelain and delivered the same day utilizing techniques and technologies relating to CAD/CAM dentistry.
Dental inlays are used to treat teeth that have decay or damage lying within their indented top surfaces. They can also be used to replace old or damaged metal fillings. Inlay placement is usually carried out over two appointments.
What are Dental Inlays?
An inlay is similar to a filling, but it lies within the cusps (bumps) on the chewing surface of your tooth. It covers one or more cusps. A dental inlay is bigger than a filling and smaller than a crown. It is bonded or cemented into place.
Dental Inlay Procedure
During your first visit to the dentist, an impression of your tooth will be taken and a temporary inlay will be placed over the tooth. The dentist will send the impression off to a dental lab, which will create the inlay to match your tooth’s specifications. When you return to the dentist’s office, the temporary inlay will be removed and the permanent one will be placed carefully over your tooth. There is no downtime after receiving a dental inlay, only a mild level of tenderness in the treated area, so you can return to work or other activities as soon as you leave the dentist.
Dental Inlay Materials and Durability
Dental inlays can be made from durable, tooth-colored porcelain, they offer much more enduring and natural-looking results than metal fillings. In addition, their customized nature allows dentists to securely bond them to the tooth surface, adding structural integrity and preventing bacteria from entering and forming cavities.
Inlays can also be made of gold and composite resin (plastic). They can last for decades. How long they last depends on the material used, teeth involved, forces of chewing and how well the patient maintains them with good oral hygiene and regular visits to a dentist.
Dental inlays and onlays are restorations used to repair rear teeth with mild to moderate decay or cracked and fractured teeth that are not sufficiently damaged to need a crown.
Ideal candidates for inlay or onlay work typically have too much damage or decay in the tooth structure to be successfully treated using a filling, but have sufficient healthy tooth remaining to avoid the need for a crown. This allows the dentist to conserve more of the patient’s original tooth structure.
There are other benefits to inlays and onlays in comparison to metal fillings:
1. Inlays and onlays are durable — they’re made from tough, hard-wearing materials which last up to 30 years.
2. They help to strengthen teeth by up to 75 percent, unlike traditional metal fillings which can actually reduce the strength of the teeth by up to 50 percent.
3. Inlays and onlays prolong tooth life and prevent the need for more dental treatment in the future.
Dental inlays and onlays are used when old fillings need to be removed or replaced. A dental inlay is similar to a filling and fits inside the cusp tips (top edges) of the tooth. A dental onlay is more extensive and extends over the cusps of the treated tooth.
During treatment the dentist removes the old fillings under local anesthesia and takes an impression of the tooth, which is sent to the dental laboratory. The new inlay or onlay is made from this mold in porcelain, gold or composite resin material. The inlay or onlay is then cemented into place at the next appointment. The inlay or onlay blends successfully with the treated tooth and the rest of the teeth to achieve a natural, uniform appearance.
How are inlays and onlays done?
It takes two appointments for the inlays and onlays treatment to be completed and to be finally bonded to the damaged area of the tooth.
Inlays and onlays are performed using very similar procedures. At the first appointment, your dentist begins the procedure by numbing the area to be treated with local anesthetic. Any decay or damage is removed by drilling, which cleans and prepares the tooth for the dental inlay or onlay.
Using a small tray filled with dental putty that fits over the teeth, the dentist takes a mold (impression) of the damaged tooth. This impression is sent off to the dental laboratory, where a dental inlay or onlay is created that will fit your tooth exactly. Inlays and onlays are usually made from porcelain, which often most closely matches the normal color of the tooth, but they can also be made from composite resin or gold. While the inlay or onlay is being created at the lab, the dentist creates a temporary restoration (cover or filling) for your tooth to protect it until your next appointment.
At the second appointment, your dentist will remove the temporary restoration and then take time to ensure the inlay or onlay fits correctly. Only when the inlay or onlay fits perfectly will the dentist bond the inlay or onlay to the tooth with a strong resin adhesive. The inlay and onlay treatment is completed with a polish to ensure a smooth and aesthetically pleasing finish.
Each visit to the dentist for inlay or onlay treatment takes about an hour, with the first appointment taking slightly longer due to the preparation process. There will probably be a little discomfort after the inlay or onlay procedure, and the new tooth surface may feel a little odd, but you soon get used to the new tooth surface and how it feels and looks in your mouth. The tissue around the treated tooth may feel sore or sensitive, but this should subside in a couple of days. If you do feel some discomfort, you can take over-the-counter pain medication to alleviate the symptoms.
Materials for Inlays & Onlays
Inlays and onlays are usually made from four types of material:
Porcelain
This tooth coloured alternative has been used for both inlays and onlays for many years. It can give a very lifelike result but may require more preparation of the remaining tooth than other choices. Wear of opposing teeth because of the abrasive qualities of certain porcelains is also an important consideration.
Gold
Pure gold is not used but instead special gold alloys are utilised which can still be gold coloured but are harder than pure gold. Gold is an excellent choice for an inlay or onlay due to its long term stability and high survival rate in the mouth. The amount of tooth preparation required can also be less than for a porcelain inlay or onlay. The potential disadvantage of gold is due to its colour. Many people would prefer a tooth coloured alternative instead but many dentists still choose gold for inlays or onlays in their own mouths.
Composite
Inlays and onlays can be constructed in composite resin. This is tooth coloured and is usually pressure cured in the dental laboratory to give it optimum strength. There are less long term studies regarding composite, but initial findings suggest that it has a similar lifespan to porcelain inlays or onlays. Many dentists like composite inlays and onlays because they are much less abrasive than porcelain and so kinder to the opposing teeth.
Zirconia
Using Computer Aided Design Computer Aided Manufacture (CADCAM) equipment it is possible to mill zirconia into inlays and onlays. This tooth coloured ceramic is exceptionally tough and resilient and studies suggest that its resistance to fracture in laboratory conditions is better than other tooth coloured inlay and onlay options. It is too early to say whether this will prove true in the mouth as these techniques are still relatively new.
Dental filling, inlay prepared by the dental technician
It can’t be emphasised enough, how important the regular tooth brushing is, as food remains sticking to the teeth surface, where bacteria start to break it down. The acids developed during such processes are damaging the tooth enamel; even the soft dentin layer and dental pulp can also be injured. This is the tooth decay process, which begins with discolouring of the tooth enamel. For the early stage only dental inspection can shed light on it. At a later stage the patient will have dull toothache and possibly discovers a black hole on it. If the patient visits the dentist in time, the tooth can be saved with a simple filling. Otherwise, only the root filling is the solution.
Tasks preceding the treatment
In all cases there is a thorough dental examination and X – ray precede the interference. In addition the patient receives information from his dentist about the planned intervention, anaesthesia, used materials and the possible complications. It is important that the patient should eat before the dental treatment, because after the anaesthetic injection, it isn’t possible to eat until the numbness holds (about 3-4 hours).
The process of making inlays
The inlay is a filling type, which is more precise than an aesthetic filling. The dental technician prepares it by the imprint and requires two dental appointments to be finished. After local anaesthesia, the dentist removes the decayed part from the tooth cavity with a drill, than takes an imprint from the shaped cavity. Than he fills the tooth temporarily. Next time he removes the provisional filling and sticks the filling produced by the dental technician in. The inlays are made of various materials.
Gold inlay
This is the best filling made by a dental technician. Gold has an advantageous character, that it can be smoothed on the teeth. As the rims of the gold inlay are smoothed on the tooth cavity, there will be no gap; therefore it is one of the longest life fillings. Gold never becomes discoloured. However, its drawback is that it is expensive and many patients do not prefer it aesthetically.
Gold-ceramic inlay
This type of filling has the advantage that it is aesthetic, the visible parts, like the bite surface is made of porcelain and only the rims are made of gold, which do not discolour.
Plastic inlay
Compared to the aesthetic filling, it has the advantage that the rims are more punctual. The dentist is fixing the inlay with a special glue into the tooth cavity. In case of the aesthetic fillings the filling material somewhat shrinks under the UV lamp effects, so a virtual gap may develop between the tooth and the filling and through it bacteria penetrates in, causing decay. In case of plastic inlays, there is a possibility to build up a tooth that has many missing parts, but it caot be restored with an aesthetic filling. The disadvantage is that due to food colouring in 3-4 years it could be discoloured.
Dental Inlays and Onlays
Dental inlays and onlays are restorations used to repair rear teeth that have a mild to moderate amount of decay. They can also be used to restore teeth that are cracked or fractured if the damage is not severe enough to require a dental crown.
Inlays and onlays are usually made from porcelain, composite resin, and sometimes even from gold. Because they can be created from tooth-colored materials, inlays and onlays are often used to replace metal dental fillings for patients who desire a more natural looking smile. Read on to find out about how inlays and onlays may be able to enhance your smile’s health and appearance.
Dental Inlays
Dental inlays are used to treat teeth that have decay or damage lying within their indented top surfaces, between the cusps of the teeth. They can also be used to replace old or damaged metal fillings. Inlay placement is usually carried out over two appointments. During your first visit to the dentist, an impression of your tooth will be taken, and a temporary inlay will be placed over the tooth. The dentist will send the impression off to a dental lab, which will create the inlay to match your tooth’s specifications. When you return to the dentist’s office, the temporary inlay will be removed and the permanent one will be placed carefully over your tooth. There is no downtime after receiving a dental inlay, only a mild level of tenderness in the treated area, so you can return to work or other activities as soon as you leave the office.
Since dental inlays and onlays can be made from durable, tooth-colored porcelain, they offer much more enduring and natural-looking results than metal fillings. In addition, their customized nature allows dentists to securely bond them to the tooth surface, adding structural integrity and preventing bacteria from entering and forming cavities.
There are several ways of obtaining an insert wax model : direct, indirect (overhead) and combined. In direct mode an insert is modeled from wax directly in the mouth. Tooth is covered with cotton rollers, a bottom and walls are moistened with water. Then a stick of modeling wax is taken and heated over a flame burner till the moment when the wax becomes plastic. A small wax taper is formed and while the wax is plastic, it is pressed with hands or a spatula in the formed cavity. Excess of wax is gently removed from the surface, and while plasticity is present, the patient is asked to close teeth in the position of central occlusion, and then play the chewing motion.
The insert surfaces at the same time takes the form characteristic for functional occlusion. Further modeling is aimed at restoring the anatomical shape of the tooth destroyed, focusing on the teeth of the other half of the jaw. Insert wax model edge should overlap the edge of the cavity (this helps to avoid insert shortening during casting and adjusting). During insert manufacture ieck cavity, simulating its edge is modeled to the level with the surrounding tooth hard tissues. For the extraction of insert model posts made from orthodontic wire are used(0.8-1mm x 1.5-
Dental Onlays
Whereas dental inlays are designed to treat decay within the cusps, or top projections, of a tooth, onlays are used to treat decay that extends to one or more of the cusps. Onlays are placed in much the same way as inlays. First, an impression of the decayed tooth is taken, and a temporary onlay is placed over the tooth. The impression is then sent to a lab, where a dental technician creates the onlay according to the tooth’s dimensions. When the patient returns to the dentist’s office, the temporary onlay is removed, and the permanent restoration is placed on the tooth and securely bonded using high-strength dental resins.
Like dental inlays, onlays can be created from tooth-colored material, which makes them virtually undetectable to the naked eye. Onlays also help to conserve more tooth structure because their use requires minimal removal a tooth’s surface. Perhaps their most important benefit, however, is that, in saving damaged teeth, onlays help patients avoid the eventual need for more extensive treatment with dental crowns, dental bridges, or dental implants.
Stump crown inserts
The main difference between these structures is the fact that this design is unique in prosthodontics, which is its main part in the root canal. This part of the structure and is called the post.
At first let us analyze the transitional form between an insert and pivot crown – the so-called stump insert, which, after fixation is covered with various crowns. The system, consisting of two independent parts (cast post insert and a crown covering it ), has several advantages over all types of pivot crown teeth and a simple insert, because it is always possible to replace covering structure without violation of fixation integrity of cast post insert.
Indications for usage of cast post inserts:
1) significant defects in dental crowns as a result of tooth decay or injury,
2) pathological abrasion of tooth hard tissue,
3) anomalies of the anterior teeth in adults;
Contraindications for usage of cast post inserts:
1) Tooth mobilityIII,
2) insufficient length of the tooth root to form a complete post insert ,
3) teeth have previously undergone resection of the tips of roots,
4) teeth with curved roots and impassable canals.
Clinical-laboratory stages of making stump crown insert by indirect method
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CLINICAL |
LABORATORY |
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1. Preparation of tooth canal and cavity. Obtaining bilayer impression (it is obtained by special way with reflection of tooth cavity and canal) from working jaw, additional impression иocclusive impression. Occlusiveimpressionisbetterobtainedwithsilicon. |
1) Casting dismountable model. 2) Modelinginsertfromwax. 3) Obtaining insert from wax. 4) Replacementwaxtometal. 5) Grinding insert. |
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II. Adjustment stump crown insert in mouth, fixing on cement. |
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During preparing the tooth root canal of the doctor takes into account the thickness of its walls. After the expansion of the channel in the mouth the doctor creates a so-called elliptical cavity depreciation in the vestibular-oral direction depth of 2.5-
Canal expands to the diameter of 1-
After the preparation of dental hard tissues a bilayer silicone impression is obtained. When obtaining the impression with a special post or canal-filler the doctor “drives in” corrective mass into the tooth root canal and thus gets the impression of the tooth root.
Combined dismountable model is prepared in the usual way. The surface of the tooth cavity and channel is smeared with compensation varnish.When the model is ready cast post insert modeling is started. For this purpose special wax is used. Typically, waxes for stump inserts are in the form of elongated flat sticks. A stick of wax is warmed, pulling it until its thickness is thinner the diameter of the entrance to the channel. Stick is entered to the model channel with slight pressure. Excess wax is cut at the level of the occlusal surface. Then it is proceed to the modeling insert overroot part. It is shaped into a truncated cone. Interocclusal distance that is formed depending on the structure, which will cover the stump insert.
After completing modeling in the thickness of the sump part of the wax composition along the tooth axis at 1-
Modeling cast post inserts at abnormalities of the teeth is different. With a view to aesthetic layout nonremovable prosthesis in the dental arch the stump part of the post insert is modeled, slightly modifying the topography of the stump. In this case one must consider the action of functional forces and know, that the inclination of the stump part to the axis of the tooth must not exceed 15 °.
With proper preparation of the abutment tooth and the observance of the laboratory technology of casting metal insert should be freely entered into the root canal and fit snugly to the hard tissues of the abutment tooth.
After adjustment it is necessary to grind roughness on insert stump off. To conduct grinding or other interventions on insert post part is unacceptable.
Pivot crown tooth by Richmond.
Indications are the same as for the stump insert. The peculiarity of indications is the 0.5-
Drawbacks of pivot crown tooth by Richmond:
1. Lack of cosmetical view. In the cervical region rim of the metal ring is always visible .
3. The presence of solder can lead to galvanoses appearance.
Clinical-laboratory stages of making pivot crown by Richmond.
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CLINICAL |
LABORATORY |
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1. Canal preparation and root stump. Root on vestibule of mouth side is grinded off lower than gum edge, and on oral cavity side it is kept of of 2,5—2 mm tooth height. Obtaining bilayer impression (is taken by special way with reflection of tooth cavity and canal) from working jaw. |
1. Casting model. 2. Making stamped cap on a stump.
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2. Adjustment a cap on a stump. In the top of a cap a hole is made. Post is inserted through the crown into the canal |
3. Making a model with a cap and a post. 4. Soldering a post to a cap. |
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3. Fitting structure in oral cavity. Choosing plastic coating colour. Obtaining impressions from upper and lower jaws. |
6. Casting model моделей 7. Modeling wax coating . 8. Replacement wax by plastic. |
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4.Fixing ready pivot tooth on cement. |
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Root cap can be made by two methods.
1. 1. The root is spanned with a wire, and its circumference is determined ; the wire is cut and its length respectively ring is manufactured with thickness 0,25-
2. 2. According to the model stamped cap from steel sleeve is made, using the same materials as for stamping crowns. In the center of the cap hole is drilled, a post is inserted through it and soldered to the surface of the cap. Subsequent phases of work are performed, as in the first method.In order to facilitate the removal of the post with a cap or overroot protection on the outer surface of the model a hole is cut through which the post is pushed out.
Pivot crown tooth by Shargorodskiy.
Indications are the same as for stump insert
Structure advantages over given:
1. Significantly fewer clinical stage
2. More reliable
3. High cosmetics
Disadvantages of pivot crown tooth by Shargorodskiy:
1. Laboratory technique of pivot crown tooth making is not accurate enough (the ring is made according to measurements not impressions);
2. The presence of solder can lead to galvanoses appearance.
Clinical-laboratory stages of making pivot crown by Shargorodskiy.
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CLINICAL |
LABORATORY |
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1 Canal preparation and root stump. Tooth root preparation is done. Root circumference is defined with thin steel wire. |
1. Steel sleeve of the same circumference as arched wire is streched. Afterwards sleeve bottom is grinded off with carborundum stone.. |
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2. Obtained steel ring is fitted to the root. A steel post is entered into root canal .Impressions are obtained. Plastic coating colour is chosen.. |
3. Casting models. 4. Fixingmodelinoccludor. 5. Plaster is removed carefully from the root, the post is taken away. 6. Then the post is placed and the whole root surface with the ring is covered with modeling wax. The tooth is modeled to wax on inner side exceed the ring slightly, and on the outer side a bed is made for a porcelain tooth or plastic. 7. Wax model with the post is formed in packing mass and cast from steel. 8. Cast is placed and soldered with the ring. 9. Plastic cvoating is made. Grinded, polished. |
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3. Fixation of pivot crown tooth on cement. |
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Pivot crown tooth by Akhmedov.
Indications are the same as for the stump insert. But for this design a sufficient height the remaining stump (1 / 3 the height of the crown damaged)is required, so this structure is intermediate between the combined crown and a classic pot crown tooth (by Richmond).
Clinical-laboratory stages of making pivot crown by Akhmedov.
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CLINICAL |
LABORATOREY |
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1. Canal preparation and root stump. Remained stump must have cone shape. Impression is obtained in plaster. |
1. Makingstampedcrownfor atoothstump. To the effect tooth complete anatomical form is recreated with wax. |
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2. Crown fitting.. Thorough fixing of a crown on a stump. Standard post adjustment. The crown is filled up with wax and put on the root. On the crown palate side by wax imprint a hole for a post is made. The crown is filled with wax again. The post is inserted through the crown and an impression is obtained. |
2. Making model with a crown and a post. 3. Soldering the post to the crown.
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3. Structure fitting in oral cavity. The crown is filled with wax again. An impression is obtained. Plastic coating colour is chosen. |
4. Vestibular surface of the crown is carved in the form of a window (as in a crown by Belkin), along the cut line retention marks are made. Crown is placed on model. 5. Waxcoatingmodeling. 6. Replacement wax by plastic. Structure polishing |
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4. Fixation of a pivot crown tooth on cement. |
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During preparing the tooth root canal of the doctor takes into account the thickness of its walls. After the expansion of the channel in the mouth the doctor creates a so-called elliptical cavity depreciation in the vestibular-oral direction depth of 2.5-
Canal expands to the diameter of 1-
After the preparation of dental hard tissues a bilayer silicone impression is obtained. When obtaining the impression with a special post or canal-filler the doctor “drives in” corrective mass into the tooth root canal and thus gets the impression of the tooth root.
Combined dismountable model is prepared in the usual way. The surface of the tooth cavity and channel is smeared with compensation varnish.When the model is ready cast post insert modeling is started. For this purpose special wax is used. Typically, waxes for stump inserts are in the form of elongated flat sticks. A stick of wax is warmed, pulling it until its thickness is thinner the diameter of the entrance to the channel. Stick is entered to the model channel with slight pressure. Excess wax is cut at the level of the occlusal surface. Then it is proceed to the modeling insert overroot part. It is shaped into a truncated cone. Interocclusal distance that is formed depending on the structure, which will cover the stump insert.
After completing modeling in the thickness of the sump part of the wax composition along the tooth axis at 1-
Modeling cast post inserts at abnormalities of the teeth is different. With a view to aesthetic layout nonremovable prosthesis in the dental arch the stump part of the post insert is modeled, slightly modifying the topography of the stump. In this case one must consider the action of functional forces and know, that the inclination of the stump part to the axis of the tooth must not exceed 15 °.
With proper preparation of the abutment tooth and the observance of the laboratory technology of casting metal insert should be freely entered into the root canal and fit snugly to the hard tissues of the abutment tooth.
After adjustment it is necessary to grind roughness on insert stump off. To conduct grinding or other interventions on insert post part is unacceptable.
Finished preparation; rubber dam removed; ready for impressioning; proximal box divergent, cusp reduction, buccal cusp with heavy bevel (no shoulder)
Buccal view
MOD amalgam on Mn first molar – occlusal fractured
Shade selection BEFORE rubber dam; need dentin shade (match shade at gingival third) and overall shade
Wax up on working cast
Special die for shade matching/staining – reason for taking the dentin shade
MOB amalgam on Mx first molar with deep pulpal floor
Existing amalgam removed, make all walls divergent and smoothed all cavosurface margins
Occl amalgam on Mn first molar, normal pulpal depth; patient complaining about pain on function- Dx: DB cusp fractured
Patient’s occlusion
Rubber dam removed following cementation
Adjust occlusion using fine diamond in high speed hand piece
Finished Preparation – MOD porcelain onlay preparation
