Dental caries is an irreversible microbial disease of the calcified tissues of the teeth, characterized by demineralization of the inorganic portion and destruction of the organic substance of the tooth , which often leads to cavitation.
Theories of caries formation
• Legend of the worm theory
• Endogenous theories
Humoral theory
Vital theory
• Exogenous theory
Chemical (acid) theory
Parasitic (septic) theory
Miller’s chemicoparasitic theory – Acidogenic theory
Proteolysis theory
Proteolysis chelation theory
Sucrose – chelation theory
• Other theories
Auto immune theory
Sulfatase theory
Etiologic factors in dental caries
• Dental caries is a multifactorial disease in which there is an interplay of 3 principle factors.
I. The host ( teeth, saliva etc.)
II. Micro flora
III. Substrate (diet)
• In addition the fourth factor, time must be considered.
Role of dental plaque
• soft, non mineralized, bacterial deposit which forms on a teeth that are not adequately cleaned
• Complex metabolically interconned highly organized bacteria/ ecosystem
• Important component of dental plaque is acquired pellicle just prior or concomitantly with bacterial colonization and may facilitate plaque formation
• Microbial in dental plaque
streptococci
actinomycetes
veillonella
• Strep. mutans chief etiological agent of dental caries
Role of microorganisms in dental caries
• Prerequisite for dental caries initiation
• A single type of microbe is capable of inducing dental caries
• Ability to produce acid prerequisite for caries induction
• Streptococcus strains are capable of inducing caries
• Organisms vary greatly in their ability to induce caries
Classification of dental caries:
1. Based on anatomical site
occlusal (pit and fissure)
smooth surface caries (proximal and cervical caries)
linear enamel caries
root caries
Pit and fissure caries
Highest prevalance of all caries bacteria rapidly colonize the pits and fissures of the newly erupted teeth
These early colonizers form a “bacterial plug” that remains in the site for long time ,perhaps even the life of the tooth
Type and nature of the organisms prevalent in the oral cavity determine the type of organisms colonizing the pit and fissure
Numerous gram positive cocci, especially dominated by s.sanguis are found in the newly erupted teeth
The appearance of s.mutans in pits and fissures is usually followed by caries 6 to 24 months later.
Sealing of pits and fissures just after tooth eruption may be the most important event in their resistance to caries.
Shape, morphological variation and depth of pit and fissures contributes to their high susceptibility to caries.
Caries expand as it penetrates in to the enamel.
Morphology of fissures
NANGO (1960):Based on the alphabetical description of shape– 4 types
V and U type: self cleansing and somewhat caries resistant
U type: narrow slit like opening with a larger base as it extend towards DEJ Caries susceptible; also have a number of different branches
K type: also very susceptible to caries
Entry site may appear much smaller than actual lesion, making clinical diagnosis difficult.
Carious lesion of pits and fissures develop from attack on their walls.
In cross section, the gross appearance of pit and fissure lesion is inverted V with a narrow entrance and a progressively wider area of involvement closer to the DEJ.
Smooth surface caries
Less favorable site for plaque attachment, usually attaches on the smooth surface that are near the gingiva or are under proximal contact. In very young patients the gingival papilla completely fills the interproximal space under a proximal contact and is termed as col. Also crevicular spaces in them are less favorable habitats for s.mutans. Consequently proximal caries is less lightly to develop where this favorable soft tissue architecture exists. The proximal surfaces are particularly susceptible to caries due to extra shelter provided to resident plaque owing to the proximal contact area immediately occlusal to plaque. Lesion have a broad area of origin and a conical, or pointed extension towards DEJ. V shape with apex directed towards DEJ.
After caries penetrate the DEJ softening of dentin spread rapidly and pulpally
Linear enamel caries
Linear enamel caries ( odontoclasia ) is seen to occur in the region of the neonatal line of the maxillary anterior teeth. The line, which represent a metabolic defect such as hypocalcemia or trauma of birth, may predispose to caries, leading to gross destruction of the labial surface of the teeth. Morphological aspects of this type of caries are atypical and results in gross destruction of the labial surfaces incisor teeth.
Root surface caries
The proximal root surface, particularly near the cervical line, often is unaffected by the action of hygiene procedures, such as flossing, because it may have concave anatomic surface contours (fluting) and occasional roughness at the termination of the enamel. These conditions, when coupled with exposure to the oral environment (as a result of gingival recession), favor the formation of mature, caries-producing plaque and proximal root-surface caries. Root-surface caries is more common in older patients. Caries originating on the root is alarming because it has a comparatively rapid progression it is often asymptomatic it is closer to the pulp 4, it is more difficult to restore. The root surface is softer than the enamel and readily allows plaque formation in the absence of good oral hygiene. The cementum covering the root surface is extremely thin and provides little resistance to caries attack. Root caries lesions have less well-defined margins, tend to be U-shaped in cross sections, and progress more rapidly because of the lack of protection from and enamel covering.
2. Based on progression
acute caries
chronic caries
arrested caries
Acute caries
Acute caries is a rapid process involving a large number of teeth. These lesions are lighter colored than the other types, being light brown or grey, and their caseous consistency makes the excavation difficult. Pulp exposures and sensitive teeth are often observed in patients with acute caries. It has been suggested that saliva does not easily penetrate the small opening to the carious lesion, so there are little opportunity for buffering or neutralization.
Chronic caries
These lesions are usually of long-standing involvement, affect a fewer number of teeth, and are smaller than acute caries. Pain is not a common feature because of protection afforded to the pulp by secondary dentin. The decalcified dentin is dark brown and leathery. Pulp prognosis is hopeful in that the deepest of lesions usually requires only prophylactic capping and protective bases. The lesions range in depth and include those that have just penetrated the enamel.
Arrested caries
Caries which becomes stationary or static and does not show any tendency for further progression. Both deciduous and permanent affected. With the shift in the oral conditions, even advanced lesions may become arrested. Arrested caries involving dentin shows a marked brown pigmentation and induration of the lesion.
Sclerosis of dentinal tubules and secondary dentin formation commonly occur Exclusively seen in caries of occlusal surface with large open cavity in which there is lack of food retention. Also on the proximal surfaces of tooth in cases in which the adjacent approximating tooth has been extracted.
3. Based on virginity of lesion
initial/primary
recurrent/secondary
Primary caries(initial)
A primary caries is one in which the lesion constitutes the initial attack on the tooth surface. The designation of primary is based on the initial location of the lesion on the surface rather than the extent of damage.
Secondary caries (recurrent)
This type of caries is observed around the edges and under restorations. The common locations of secondary caries are the rough or overhanging margin and fracture place in all locations of the mouth. It may be result of poor adaptation of a restoration, which allows for a marginal leakage, or it may be due to inadequate extension of the restoration. In addition caries may remain if there has not been complete excavation of the original lesion, which later may appear as a residual or recurrent caries.
4. Based on extent of caries
incipient caries
occult caries
cavitation
Incipient caries
The early caries lesion, best seen on the smooth surface of teeth, is visible as a ‘white spot’. Histologically the lesion has an apparently intact surface layer overlying subsurface demineralization. Significantly may such lesion can undergo remineralization and thus the lesion per se is not an indication for restorative treatment. These white spot lesion may be confused initially with white developmental defects of enamel formation, which can be differentiated by their position away from the gingival margin, their shape (unrelated to plaque accumulation) and their symmetry (they usually affect the contralateral tooth). Also on wetting the caries lesion disappear while the developmental defect persist
It is believed that bite wing and OPG radiographs along with noninvasive adjuncts like fiber optic transillumination (FOTI),laser luminescence, electrical resistance method (ERM) are used for diagnosis these occlusal lesions. These lesion are not associated with microorganisms different to those found in other carious lesion. These carious lesion seem to increase with increasing age. Occult carious lesion are usually seen with low caries rate which is suggestive of increase fluid exposure. It is believed that increased fluid exposure encourages remineralization and slow down progress of the caries in the pit and fissure enamel while the cavitations continues in dentine, and the lesions become masked by a relatively intact enamel surface. These hidden lesions are called as fluoride bombs or fluoride syndrome. Recently it is seen that occult caries may have its origin as pre-eruptive defects which are detectable only with the use of radiographs. Once it reaches the dentinoenamel junction, the caries process has the potential to spread to the pulp along the dentinal tubules and also spread in lateral direction. Thus some amount of sensitivity may be associated with this type of lesion. This may be generally accompanied by cavitation
5. Based on tissue involvement
Initial caries
Superficial caries
Moderate caries
Deep caries
Deep complicated caries
Dental caries can be divided into 4 or 5 stages
1. Initial caries: Demineralization without structural defect. This stage can be reversed by fluoridation and enhanced mouth hygiene
2. Superficial caries (Caries superficialis):Enamel caries, wedge-shaped structural defect. Caries has affected the enamel layer, but has not yet penetrated the dentin.
3. Moderate caries (Caries media): Dentin caries. Extensive structural defect. Caries has penetrated up to the dentin and spreads two-dimensionally beneath the enamel defect where the dentin offers little resistance.
4. Deep caries (Caries profunda): Deep structural defect. Caries has penetrated up to the dentin layers of the tooth close to the pulp.
5. Deep complicated caries (Caries profunda complicata) :Caries has led to the opening of the pulp cavity (pulpa aperta or open pulp).
6. Based on pathway of caries spread
forward caries
backward caries
“Forward-backward” classification is considered as graphical representation of the pathway of dental caries.
ENAMEL
First component of enamel to be involved in carious process is the interprismatic substance. The disintegrating chemicals will proceed via the substance, causing the enamel prism to be undermined. The resultant caries involvement in enamel will have cone shape. In concave surface (pit and fissures) base towards DEJ. In convex surfaces (smooth surface) base away from DEJ.
DENTIN
First component to be involved in dentin is protoplasmic extension within the dentinal tubules. These protoplasmic extension have their maximum space at the DEJ, but as they approach the pulp chamber and root canal walls, the tubules become more densely arrange with fewer interconnections. So caries cone in dentin will have their base towards DEJ.
Decay starts in enamel then it involves the dentin. Wherever the caries cone in enamel is larger or at least the size as that of dentin, it is called forward decay (pit decay). However the carious process in dentin progresses much faster than in enamel, so the cone in dentin tends to spread laterally creating undermined enamel. In addition decay can attack enamel from its dentinal side. At this stage it becomes backward decay.
7. Based oumber of tooth surface involved
Simple – caries involving only one tooth surface
Compound – caries involving two surfaces of tooth
Complex – caries that involves more than two surfaces of a tooth
8. Based on chronology
early childhood caries
adolescent caries
adult caries
It has been stated that over a lifetime, caries incidence i.e. the number of new lesions occurring in a year, shows three peaks-at the ages 4-8,11-19 and 55-65 years.
Early childhood caries
Early childhood caries would include, two variants: Nursing caries and rampant caries. The difference primarily exist in involvement of the teeth (mandibular incisors) in the carious process in rampant caries as opposed to nursing caries.
Classification of early childhood caries
Type I (MILD )
Involves molars and incisors
Seen in 2-5 years
Causecariogenic semisolid food +lack of oral hygeine
Type II (MODERATE)
Unaffected mandibular incisors
Soon after first tooth erupts
Causeinappropriate feeding +lack of oral hygiene
Type III (SEVERE)
All teeth including mandibular incisors
Causemultitude of factors
Nursing caries
Seen in infant and toddler
Affects primary dentition
Mandibular incisors are
not involved
Etiology: improper bottle feeding, pacifier dipped in honey/other sweetner
Rampant caries
Seen in all ages, including adoloscennce
Affects primary and permanent dentition
Mandibular incisors are also affected
Etiology (multifactorial): frequent snacks, sticky refined CHO, decreased salivary flow, genetic background
Teenage caries (adolescent caries)
This type of caries is a variant of rampant caries where the teeth generally considered immune to decay are involved. The caries is also described to be of a rapidly burrowing type, with a small enamel opening. The presence of a large pulp chamber adds to the woes, causing early pulp involvement
Adult caries
With the recession of the gingiva and sometimes decreased salivary function due to atrophy, at the age of 55-60 years, the third peak of caries is observed. Root caries and cervical caries are more commonly found in this group. Sometime they are also associated with a partial denture clasp.
9. Based on whether caries is completly removed or not during treatment
Residual caries
Residual caries is that which is not removed during a restorative procedure, either by accident, neglect or intention. Sometimes a small amount of acutely carious dentin close to the pulp is covered with a specific capping material to stimulate dentin deposition, isolating caries from pulp. The carious dentin can be removed at a later time.
10. Based on tooth surface to be restored
Most widespread clinical utilization
O for occlusal surfaces
M for mesial surfaces
D for distal surfaces
F for facial surfaces
B for buccal surfaces
L for lingual surface
Various combinations are also possible, such as MOD –for mesio-occluso-distal surfaces.
11. Black’s classification
Class 1 lesions:
Lesions that begin in the structural defects of teeth such as pits, fissures and defective grooves. Locations include
Occlusal surface of molars and premolars.
occlusal two thirds of buccal and lingual surfaces of molars and premolars.
Class 2 lesions:
They are found on the proximal surfaces of the bicuspids and molars.
Class 3 lesions:
Lesions found on the proximal surfaces of anterior teeth that do not involve or necessitate the removal of the incisal angle.
Class 4 lesions:
Lesions found on the proximal surfaces of anterior teeth that involve the incisal angle.
Class 5 lesions:
Lesions that are found at the gingival third of the facial and lingual surfaces of anterior and posterior teeth.
Class 6 (Simon’s modification):
Lesions involving cuspal tips and incisal
12.World health organization (WHO) system
In this classification the shape and depth of the caries lesion scored on a four point scale
D1. clinically detectable enamel lesions with intact (non cavitated) surfaces
D2. Clinically detectable cavities limited to enamel
D3. Clinically detectable cavities in dentin
D4. Lesions extending into the pulp
Parental influence and dental treatment
Parents are vital for positive reinforcement over any treatment objective. Programmes of treatment must be designed to reduce any chances of making parents or their children feel guilty. Design of treatment programmes should also allow goals to be achieved one by one, never overloading parent or child.
Dentist-patient relationship
Each patient is a unique individual and should be treated as such. Overall, it is fair to conclude that while the technical skill of a dentist is of concern, the most important factors for a patient are gentle friendly manner, explanation of treatment procedures and the ability to keep pain to a minimum. The structure of the dental consultation:
1. Greeting – by name
2. Preliminary chat: non-dental topics first, then dental; listen to the answers!
3. Preliminary explanation: clinical and preventive objectives in language that can be understood
4. Business: during treatment, constantly check the patient is not in pain and explain and discuss what you are doing; summarise what you have done to patient and parent and offer aftercare advice 5. Health education: constantly reinforce advice about maintaining a healthy mouth and give advice as though you mean it; always set realistic objectives
6. Dismissal: a clear signpost that the appointment is over, using the child’s name and a definite farewell.
Anxious and unco-operative children
The extent of anxiety does not relate to dental knowledge but is an amalgam of personal experiences, family concerns, disease levels and general personality traits. It is, therefore, not easy to pinpoint aetiological agents and measure anxiety. In addition, there is no standard measure of anxiety. Helping anxious patients cope Several approaches can help to reduce coping problems: • reducing uncertainty — tell, show, do send letter home explaining details of proposed visit acclimatisation programmes modelling: videos or a live model cognitive approaches identification of beliefs: try to get individuals to identify and alter their dysfunctional beliefs, useful for all focused types of anxiety distraction attempts to shift attention from dental setting towards another kind of situation, e.g. videos, headphones with music or stories relaxation: useful for high levels of tension; aims to bring about deep muscular relaxation; trained therapist is required systematic desensitisation: working through various levels of feared situations from ‘mildest’ to ‘most anxiety’ inhalation sedation: usually for ages 5 and over.
Care programme
History involves social, medical and dental information
Social. Name, address, age, school, siblings, parental occupations. This allows clinician to establish rapport. Try and assess social background, knowledge of dentistry and the family’s expectations. Medical. Apart from allowing safe delivery of dental care, two additional factors can be gleaned: children with medical conditions may have a negative attitude to treatment because of the time they have spent in hospitals; they may also be more likely to fail dental appointments owing to the disruption in education that the medical problem has already caused.
Dental. Past dental experiences may give an indication of how the child will cope with proposed treatment. Parental attitude to treatment is important. A treatment plan must be modified to accommodate this. Establish exactly why they have come. The answers from child and parent may be different!
Examination
1. Clinical examination
The clinical examinatioeed not involve sitting in the dental chair at the first visit. Examine the child as a persoot just a mouth. Extraoral. General appearance is noted; percentile charts are useful way of monitoring height and weight. The head and neck is examined making a sketch of any lesions/marks. Intraoral. Soft tissues may be indicator of systemic disease. The relationship between periodontal condition and oral hygiene may indicate an underlying condition. Occlusion factors include crowding, malalignments, mandibular deviations and habits. The condition of the teeth is noted; are they clean and dry?
2. Radiographic examination
Guidelines for prescription of radiographs in children are shown in Table 13. There are 3 general indications for taking radiographs in children. Caries diagnosis. At least 50% more approximal lesions can be diagnosed by bitewing radiographs than with clinical examination. New orthopantogram (OPT) films may be very efficient at diagnosing occlusal caries, but bitewings remain essential in diagnosis of ‘occult’ occlusal caries. Abnormalities in dental development. All children at age 8 or 9 years should have an OPT to identify disturbances in development of the dentition in terms of the number, position and form of the teeth. Precise location of maxillary canines can then be achieved by intraoral parallex technique. Detection of bony or dental pathology. Periapicals examined for individual teeth; panoramic views for larger pathology or trauma.
3. Special investigations
There a number of special tests that are sometimes relevant: vitality testing: not suitable for primary dentition; in permanent dentition, no tests are reliable but the electric pulp tester is probably the best culture and sensitivity: bacterial, fungal and viral infections blood tests: haematological, biochemical, bacteriological and virological examination.
Treatment planning
Planning should incorporate, management of pain, consider all teeth of poor prognosis long-term treatment planning, to include attitudes and motivation preventive care, tailored to each individual restorative care, realistic aims are important, aesthetic considerations, children can be under considerable peer pressure over their appearance.
Prevention
The four practical ‘pillars of prevention’ are: diet, fluoride, fissure sealants and plaque control.
1. Dietary factors
Fluoride is the only dietary nutrient that has any preemptive influence on a tooth’s future susceptibility to caries (major effect is posteruptive). Non-milk extrinsic sugars (NME) are the dietary threat: sucrose, glucose, fructose, maltose. Intrinsic sugars (lactose in milk and sugars in fruit and vegetables) are not generally a threat to dental health. However, even lactose in milk in a bottle at night or in on-demand breast feeding can be cariogenic. Starchy staple foods (potatoes, bread, rice, pasta) are not a cause of dental caries, but mixtures of finely ground heat-treated starch and sugars (biscuits) are likely to be cariogenic. The frequency of sugar intake and the total quantity of sugar intake are important. In British schoolchildren two-thirds of NME intake is from confectionery, soft drinks and table sugar. Unnecessary addition of extra sugars to milk and other feeds is the cause of caries in young children, especially in immigrant minorities. Non-sugar sweeteners allowed for use in food and drinks can be considered for practical purposes as noncariogenic. A very slow metabolism for some bulk sweeteners in plaque is not important. There are two groups of non-sugar sweeteners
• bulk: sorbitol, mannitol, isomalt, xylitol, lactitol and hydrogenated glucose syrup
• intense: saccharin, acesulphame K, aspartame, thaumatin. Bulk sweeteners have a laxative effect and should not be given to children under the age of 3 years.
Dietary advice
Dietary advice should be positive, practical and personal to the patient and parent, and take into account cooking skills and financial considerations. It can only be achieved with a written 3- or 4-day diary history. Advise against drinks with a high sugar content and titratable acidity. NMEs should be kept to main meals and acceptable alternatives should be suggested for between meal snacks. No food or drink should be taken within 1 hour of bed and no drink should be available (apart from water) during night.
2. Fluoride
Fluoride has the ability to increase enamel resistance to demineralisation as well as decreasing acid production in plaque and increasing remineralisation. Although it has a preeruptive effect its major role is posteruptive. Fluoride can be delivered systemically (swallowed) or topically (applied to the teeth). Water, salt and milk have and are being used throughout the world as systemic vehicles for fluoride. In the USA, 56% of the population receive fluoridated water, in Ireland 60% and in the UK 10%. Fluoride drops/tablets, which have a topical and a systemic effect, are an established and proven method of fluoridation. However, there has been a recommended daily reduction in dosage during the 1990s because it is recognised that the original dose was probably too high and that fluoride is now more likely to be ingested from other sources (toothpaste and water). Toothpastes have been responsible worldwide for the large fall in caries. In 1970, virtually no toothpaste contained fluoride; by 1978, 97% contained fluoride. Most adult pastes contain 1000–1500 ppm fluoride ions (used by those over age 5 years). Children’s pastes containing up to 500 ppm are available for those under 5. Only a smear of paste should be used and supervision of brushing is needed to prevent swallowing as this is a risk for fluorosis. Fluoride mouthrinses for age 6 years and over are a valuable daily adjunct. The 0.05% NaF ( ~ 225 ppm F–) mouthrinse probably has better compliance than weekly 0.2% NaF ( = 900 ppm NaF) application. Finally, professionally applied fluoride solutions, gels and varnishes complete the fluoride armamentarium. Varnishes are easier to apply than the solutions and gels and can be applied effectively to all ages. Although each individual method of fluoride application is effective, a combination of methods may achieve greater benefit (Table 14).
3. Fissure sealing
The most effective sealant is bis-GMA. At least 50% of sealants are retained for 5 years and their effectiveness in reducing and delaying the onset of caries is not in doubt. Both unfilled and filled resins and clear and opaque resins have been used to equal effect. Isolation after etching and drying is essential to success. Indications for patient selection and tooth selection
are: special needs: medical, physical, intellectual, social disability caries in primary dentition occlusal surfaces of permanent molars, cingulum pits of upper incisors
• seal as soon as moisture control permits continue to monitor sealed teeth clinically and radiographically.
4. Plaque control
Caries reduction cannot be achieved by tooth brushing alone. However, toothbrushing will control gingivitis and periodontal disease and is an important way of conveying fluoride to the tooth surface. Chemical control of plaque with chlorhexidine is effective, but because of its side-effects (staining of teeth, altered taste sensation) it should only be used as a short term adjunct to periodontal care. The effects of all the practical ‘pillars of prevention’ are additive and all treatment plans should take into account age, caries risk, water fluoride level and cooperation.
Primary teeth
Pit and fissure caries
The primary fissures are shallower than their permanent counterparts and the presence of caries is a sign of high caries activity. The material of choice is an adhesive material either a GIC, resin-modified GIC, or compomer. Manufacturers’ instructions for these materials should be followed assiduously utilising tooth conditioners and bonding resins where stated.
Approximal caries
Minimal approximal cavity. A minimal approximal cavity with no occlusal dovetail is repaired using the retentive box preparation’. The material of choice is a compomer, which has greater mechanical strength than GIC or resin-modified GIC and which still releases fluoride. The approximal box is prepared as in Box 20 but without an occlusal dovetail. Additional retention grooves may be achieved by placing grooves into dentine using half-round burs along the gingival floor and lingual wall. The buccal wall is avoided because of the large buccal pulp horn in primary molars (Fig. 79).
Approximal caries with occlusal extension. The success rate of amalgam in approximal caries with occlusal extension has been reported as being 70-80%. (Box 20).
Fig. 79 Approximal posterior caries without pit and fissure caries: the ‘retentive box preparation’, (a) Position of the caries, (b) Occlusal view showing cavity or shadow, (c) Access leaving sliver of enamel, (d) Extension of walls and removal of caries from the amelodentine junction, (e) Grooves placed on lingual wall and gingival floor, not on buccal wall.
The failure rate of GICs is higher than amalgam: 33% over 5 years compared with 20% for amalgam. Consequently, amalgam is still the material of choice. However, recent clinical trials of 3 years’ duration show that compomers can be as durable as amalgam.
Restorations on more than two surfaces. Restorations extending onto more than two surfaces include cusp replacement and endodontically treated teeth. The stainless steel crown is the material of choice, with survival times in excess of 40 months. Their replacement rate is low at 3% compared with 15% for amalgams. Although initially they are more expensive, in the long term they are cost-effective. Problems of colour are gradually being overcome by the introduction of tooth-coloured veneer crowns. Once learnt, their placement technique (Box 21) is less technically demanding than intracoronal restorations in primary teeth and they should certainly be considered for any tooth for which the dentist cannot be sure that an alternative restoration would survive until the tooth is exfoliated.
Anterior teeth
Treatment options for anterior teeth depend on the severity of the decay and the age and co-operation of the patient. In the pre-school child, caries of the upper primary incisors is usually a result of ‘nursing caries syndrome’: frequent or prolonged consumption of fluids containing NME sugars from a bottle or feeder cup. Progression of decay is rapid, commencing on the labial
Fig. 80 Posterior caries with pit and fissure caries, (a) Position of the caries, (b) Removal of the occlusal caries, (c) Access to the approximal caries (sliver of enamel left), (d) Establish gingival floor of box and remove remaining enamel at the contact point, (e) Deepen the axio-pulpal line angle centrally as shown (f) in the cavity profile. The buccal and lingual walls of the cavity should be just clear of the broad contact areas. surface and quickly encircling the teeth. The most suitable form of restoration is the ‘strip crown technique’, which uses a celluloid crown former with light-cured composite resin to restore crown morphology. In older children over 3 or 4 years of age, new lesions of primary incisors indicate high caries activity. These lesions usually occur approximally and do not progress as quickly as nursing caries. They can be restored with GIC, compomer or composite resin.
Permanent teeth
Bitewing radiographs should be taken prior to any instrumentation of a tooth surface. For a clean fissure with no radiographic evidence of caries, a fissure sealant is the treatment of choice in molar teeth. If the fissure is stained with no radiographic evidence of caries, it will require clinical exploration. If clinical exploration reveals dentinal caries, then a restoration will be required. If dentinal caries is detected radiographically, a restoration is obviously necessary.
Fissure sealants
Consideratioeeds to be given whether to use a clear, coloured or opaque resin sealant or whether to use a non-filled or filled resin Early sealants were clear in order to check that caries was not developing under the sealant. However, the margins were difficult to see and coloured and opaque materials were introduced in order to see areas of sealant fracture and loss. The final choice is with the individual clinician. Bitewing radiographs are an important part of sealant review as it only needs failure of one small part of the sealant-enamel bond for leakage to occur. GIC may be useful as temporary sealants in individuals with highly active caries until teeth have erupted sufficiently to allow conventional sealants Indeed they are similarly applicable for patients in whom isolation for placement of conventional sealants is impossible. They may require more frequent replacement because of their brittleness in thin section but they will provide occlusal protection and a reservoir of fluoride for release to surrounding enamel.
Stained fissure with no radiographic caries
The fissure should be explored with a small round bur. If the lesion stays within enamel, a fissure sealant is placed. If the lesion extends into dentine the treatment is as for pit and fissure caries.
Pit and fissure caries
If occlusal contacts are retained on enamel in a pit and fissure caries, a composite restoration is applicable, taking the opportunity to fissure seal non-carious fissures; this is known as a ‘preventive resin restoration’ The durability of preventive resin restorations is proven to be as good as occlusal amalgam restorations and is achieved with removal of significantly less enamel. If the occlusal contacts are not retained on enamel, then amalgam is the material of choice as it will not wear significantly, nor will it wear opposing teeth. Technique for placement of a preventive resin Restoration Figure 81 shows the placement of a preventive resin restoration.
1. Local anaesthesia and isolation.
2. Access questionable fissure with a small high-speed diamond bur.
3. Remove carious dentine and enough enamel to allow complete caries removal.
4. Remove caries from deeper dentine with a slowspeed round bur.
5. Place GIC liner over dentine, extending it up to amelodentinal junction, light-curing if necessary. 6. Gel/liquid etchant is placed on enamel margins for 20 seconds, followed by wash and dry. It is not necessary to etch the liner, sufficient roughening of the surface of GIC will result from washing. 7. Place a thin layer of bonding resin into the cavity and onto enamel margins. Cure for 20 seconds. 8. Incrementally fill the cavity with hybrid composite resin. Polymerise the resin until it is level with the occlusal surface.
9. Flow opaque unfilled fissure sealant over the restoration and the entire occlusal fissure pattern and cure for 20 seconds.
10. Check the occlusion.
Approximal caries
Amalgam remains the material of choice even in modern conservative cavity designs that do not sacrifice as much sound tissue as Black’s original designs. Nonmetallic restorative materials in these situations show significant wear after 4-5 years, which may be a manifestation of fatigue within the resin matrix.
Anterior teeth
Composite resin or the newer reinforced compomers should be the materials of choice. Incisal edge restorations require careful design to utilise more surface area of normal enamel rather than resorting to dentine pins.
The colour of a young persons teeth is of great importance. Peer group pressure can be significant, and teasing about size, position and colour of teeth can be very harmful. The most useful method of classification for the clinical management of discoloration is one that identifies the main site of discoloration Once the aetiology has been identified, the most appropriate method of treatment can be chosen. Treatment emphasis should be on minimal tooth preparation. As a general rule, microabrasion should be the first-line treatment for all cases of enamel opacities and mottling; composite resin in the form of localised or full veneers is used in preference to porcelain.
Treatments
1. Based on treatment and restoration design (black’s)
Class 1 restoration:
include the structural defects of teeth such as pits, fissures and defective grooves.
Locations include
Occlusal surface of molars and premolars.
occlusal two thirds of buccal and lingual surfaces of molars and premolars.
Lingual surfaces of anterior tooth.
Class 2 restoration :
They are found on the proximal surfaces of the bicuspids and molars.
Class 3 restoration :
restoration on the proximal surfaces of anterior teeth that do not involve or necessitate the removal of the incisal angle.
Class 4 restoration :
restoration on the proximal surfaces of anterior teeth that involve the incisal angle.
Class 5 restoration :
restoration at the gingival third of the facial and lingual surfaces of anterior and posterior teeth.
Class 6 (Simon’s modification):
restoration involving cuspal tips and incisal edges of teeth.
2. Other modifications
Charbeneu’s modification:
a) Class 2: cavity on single proximal surface of bicuspids and molars
b) Class 6: cavities on both mesial and distal proximal surfaces of posterior teeth that will share a common occlusal isthmus
c) Lingual surfaces of upper anterior teeth.
d) Any other unusually located pit or fissure involved with decay.
3. Sturdevant’s classific
Simple cavity – cavity involving only one tooth surface
Compound cavity- cavity involving two surfaces of tooth
Complex cavity – cavity that involves more than two surfaces of a tooth
4 .Finn’s modification of Black’s cavity preparation for primary teeth
Class1 : Cavities involving the pits and fissures of molar teeth and the buccal and lingual pits of all teeth.
Class 2: cavities involving proximal surface of molar teeth will access established from the occlusal surface.
Class 3: cavities involving proximal surfaces of anterior teeth which may or may not involve a labial or a lingual extension
Class 4: a restoration of the proximal surface of an anterior tooth which involves the restoration of an incisal angle.
Class 5: cavities present on the cervical third of all teeth, including proximal surface where the marginal ridge is not included in the cavity preparation.
The four sizes of carious lesions
Size1:Minimal involvement of dentin just beyond treatment by remineralization alone.
Size 2: Moderate involvement of dentin. Following cavity preparation, remaining enamel is sound, well supported by dentin and not likely to fail under normal occlusal load. The remaining tooth structure is sufficiently strong to support the restoration.
Size 3: the cavity is enlarged beyond moderate. The remaining tooth structure is weakened to the extent that cups or incisal edges are split, or are likely to fail or left exposed to occlusal or incisal load. the cavity needs to be further enlarged so that the restoration can be designed to provide support and protection to the remaining tooth structure.
Size4: Extensive caries with bulk loss of tooth structure has already occurred.
Treatments for discoloured teeth can be used in children and adults, although some are not suitable for children younger than teenage. Techniques use abrasion, bleaching and restorations. The exact mechanism by which bleaching occurs remains unknown. Theories of oxidation, photo-oxidation and ion exchange have been suggested.
The hydrochloric acid pumice microabrasion technique
The microabrasion method is a controlled removal of surface enamel in order to improve discolorations that are limited to the outer enamel layer It is achieved by a combination of abrasion and erosion and the term ‘abrosion’ is sometimes used. No more than 100 μm of enamel are removed. Once completed, the procedure should not be repeated. Too much enamel removal is potentially damaging to the pulp and cosmetically the underlying dentine colour will become more evident.
Indications
• fluorosis
• idiopathic speckling
• postorthodontic demineralisation
• prior to veneer placement for well-demarcated stains
• white/brown surface staining, e.g. secondary to
primary predecessor infection or trauma (Turner teeth).
Effectiveness
Critical analysis of the effectiveness of the technique should not be made immediately but delayed for at least
1 month as the appearance of the teeth will continue to improve over this time. Experience has shown that although white mottling is often incompletely removed it does become less perceptible. This phenomenon has been attributed to the relatively prismless layer of compacted surface enamel produced by the ‘abrasion’ technique, which alters the optical properties of the tooth surface. Long-term studies of the technique have found no association with pulpal damage, increased caries susceptibility or significant prolonged thermal sensitivity. Patient compliance and satisfaction is good and any dissatisfaction is usually a result of inadequate preoperative explanation. The technique is easy to perform for operator and patient and is not time consuming. Removal of any mottled area is permanent and is achieved with an insignificant loss of surface enamel. Failure to improve the appearance by the microabrasion technique does not have any harmful effects and may make it easier to mask some lesions with veneers.
ETIOLOGY
Historical studies
In 1883 Miller showed that carbohydrates when incubated with saliva caused demineralisation of extracted teeth. This showed for the first time that there was some scientific basis for dental caries being caused by diet. In 1940 studies by Stephan showed that dental plaque had a resting pH of 6.5–7; when exposed to fermentable sugars, such as sucrose, glucose or fructose, the pH fell rapidly to a pH well below 5, followed by a slow recovery to the original level over the next 30–60 minutes.
Teeth tissues are the most vulnerable during final mineralization. In this case the most important role plays nutrition, lack amount of vitamin D and minerals, including calcium and fluoride in the body, hormonal and metabolic system diseases as general factors. An origin and development of the caries process is influenced also by such factors: presence of orthodontic pathology, high viscosity of saliva, insufficient buffering properties of saliva.
MICROBIOLOGY
Substantial evidence indicates that streptococci are essential for development of caries, particularly of smooth (interstitial) surfaces. These are viridans streptococci which are a heterogeneous group including Streptococcus mutans, S. sobrinus, S.salivarius, S. mitior and S. sanguis.
Viridans streptococci vary in their ability to attach to different types of tissues, their ability to ferment sugars (particularly sucrose), and the concentrations of acid thus produced. They also differ in the types of polysaccharides that they form. Certain strains of S. mutans are strongly acidogenic and, at low pH, with freely available sucrose, also store an intracellular, glycogen-like, reserve polysaccharide. When the supply of substrate dries up, this reserve is metabolised to continue acid production for a time. Drastic reduction in dietary sucrose intake is followed by virtual elimination of S. mutans from plaque and reduces or abolishes caries activity. When sucrose is made freely available again S. mutans rapidly recolonises the plaque. However, simple clinical observation of the sites (interstitially and in pits and fissures) where dental caries is active, shows that the bacteria responsible are not those floating free in the saliva. Dental caries develops only at the interface between tooth surface and dental plaque in stagnation areas.
Saliva affects caries etiology through the rate of secretion and composition. Saliva affects the integrity of teeth by the composition of (buffer system, calcium and phosphate). By the cleansing action of saliva (oral clearance), it can affect the number of oral microorganisms and food debris from the mouth. The oral immune system (specific and non specific) affect to a large degree the cariogenic bacteria.
It is the acidic pH that demineralises enamel and dentine. The critical pH for enamel is around 5.2–5.5 while for dentine it is around pH 6.0. The critical pH is defined as the pH at which the tooth tissue loses mineral to the saliva or plaque. The differences in pH are important in determining the rate of progression of enamel and root caries.
PATHOGENESIS
Clinically, bacterial plaque is a tenaciously adherent deposit on the teeth. It resists the friction of food during mastication, and can only be readily removed by toothbrushing. However, neither toothbrushing nor fibrous foods will remove plaque from inaccessible surfaces or pits (stagnation areas). Plaque becomes visible, particularly on the labial surfaces of the incisors, whentoothbrushing is stopped for 12-24 hours. It appears as a translucent film with a matt surface that dulls the otherwise smooth and shiny enamel. It can be made obvious when stained with disclosing agents. In stagnation areas where it is undisturbed, plaque bacteria can form acid from sugars over sufficiently long periods as to attack tooth surfaces. Adhesion of bacteria to the teeth from which they would otherwise be washed away is an essential requirement for the colonisation of enamel.
THE EPIDEMIOLOGY OF CARIES
It cannot be stated too often that dental caries has a multi-factorial aetiology and the factors that have been identified as important in the development of caries are the consumption of fermentable sugars, the microflora of the dental plaque and the tooth surface.The prevalence and incidence of dental caries in a given population and in an individual are dependent upon the outcome of the interactions of these factors. These individual factors are, in turn, determined by a number of apparently unrelated factors which necessarily impact on them. The frequency of use of fluoride-containing toothpastes, which modify the tooth surface and may influence the acidogenicity of dental plaque, and the frequency of consumption of fermentable sugars by children may both, for example, be determined by the educational level and income of apparent, while the availability of fluoride-containing tooth-pastes may be determined by the commercial policy of the toothpaste producer.
INDICES OF DENTAL CARIES
Research over the years has shown that caries is a preventable and controllable disease. To apply measures which can prevent or control caries, a reliable picture of it in a population is prerequisite; this can only be obtained if we have a reliable caries assessment system (index).
For several decades dental researchers are following and teaching DMF index developed by Klein, Palmer and Knutson in 1938 for assessing dental caries. World health organization has adopted this index in its oral health assessment form for conducting national oral health surveys [16]. Various reasons can be stated for its continued use for assessing caries, foremost of them are: it is simple to use, valid and reliable, that is why it is still being used for assessment and comparison of caries status of the population groups around the world.
MEASUREMENT OF INTENSITY OF CARIES
*Permanent teeth index:
The DMF index is the average number of permanent teeth per person which are decayed (D), missing because of caries (M), or filled (F). It is a quantitative expression of the life-time caries experience of the permanent teeth. In the calculation of the DMF index, the numerator is the total number of DMF teeth and the denominator is the total number of persons examined.
Decayed-Missing-Filled Index ( DMF ) which was introduced by Klein, Palmer and Knutson in 1938 and modified by WHO:
1-DMF teeth index (DMFT) which measures the prevalence of dental caries/Teeth.
2- DMF surfaces index (DMFS) which measures the severity of dental caries.
The components are:
D component:
Used to describe (Decayed teeth) which include:
1. Carious tooth.
2. Filled tooth with recurrent decay.
3. Only the root are left.
4. Defect filling with caries.
5. Temporary filling.
6. Filled tooth surface with other surface decayed.
M component:
Used to describe (Missing teeth due to caries) other cases should be excluded these are:
1. Tooth that extracted for reasons other than caries should be excluded,
which include:
a-Orthodontic treatment.
b-Impaction.
c-Periodontal disease.
2. Un-erupted teeth.
3. Congenitally missing.
4. Avulsion teeth due to trauma or accident.
F component:
Used to describe (Filled teeth due to caries). Teeth were considered filled without decay when one or more permanent restorations were present and there was no secondary (recurrent) caries or other area of the tooth with primary caries. A tooth with a crown placed because of previous decay was recorded in this category. Teeth stored for reason other than dental caries should be excluded, which include:
1. Trauma (fracture).
2. Hypoplasia (cosmetic purposes).
3. Bridge abutment (retention).
4. Seal a root canal due to trauma.
5. Fissure sealant.
6. Preventive filling.
DIAGNOSTIC METHODS FOR DENTAL CARIES
Clinical methods
Caries occurs on the occlusal, aproximal and buccal/lingual surfaces of teeth. On smooth surfaces the lesions normally develop close to the gingival margin and are often covered in plaque. Those developing in fissures and aproximal surfaces are more difficult to detect and diagnosis usually involves indirect methods. Diagnostic tests have been developed to maximise the accuracy of caries detection on each surface. On the buccal and lingual surfaces the optimal assessment is the visual appearance of the surface. A white spot lesion can be seen when enamel has been cleaned and dried. The area is often covered in plaque. On those surfaces hidden from direct visual examination, radiographic examination is the most commonly used diagnostic technique.
Radiography
Bitewing radiographs are relatively reliable for detecting aproximal lesions but less so for occlusal lesions. Radiolucenciesdeveloping below the contact areas appear like horizontal V-shaped notches in enamel-only lesions. As the lesion progresses into dentine, a mushroom formation occurs as the enamel appears to be undermined along the enamel–dentine junction (EDJ). The situation is more difficult to assess on the occlusal surfaces as the more mineralised and thicker enamel partly obscures the lesion progression. The advancing lesion is therefore relatively underdiagnosed by radiographs. A rough guide suggests that a lesion is 25% more advanced than when estimated from a radiograph. A bitewing radiograph needs to be taken correctly to have the most diagnostic yield. Film holders yield the most accurate results and ensure that the X-rays pass perpendicularly through the crown of the tooth. This reduces the amount of overlap. A clear outline should be visible of the enamel overlying the dentine and allows good distinction between the two tissues. A clear change in the radiolucency of the tooth can then be seen. Caries appears as radiolucent shadowing and occurs at susceptible sites. Aproximally, this will occur below the contact area and above the alveolar bone. Beneath the occlusal surfaces the faint outline of caries can be detected. The radiolucent zone appears as a diffuse zone beneath the enamel. The extent of the lesion spread is more difficult to visualise as the bulk of the enamel and dentine partly obscures the X-rays; this results in a less accurate assessment of occlusal caries compared to that occurring aproximally. The frequency of bitewing radiographs should be assessed for each individual. A high caries risk individual might require radiographs taken at yearly intervals whereas someone with no caries experience for a number of years would need them less frequently, e.g. every 4–5 years.
Transillumination
This is a rarely used technique to assess caries on molars and premolars but more commonly used on anterior teeth. Direct light reflected by dental mirrors on to the teeth can highlight darkened shadows present between the aproximal surfaces of upper anterior teeth. A carious lesion shows as a darkened shadowed area in dentine surrounded by a normal coloured zone. Light curing lamps can be used to examine the surfaces as white intraoral lights are not common. These lights need to be directed between the contacts of teeth and have sufficient intensity to show the caries. Generally, ambient light sources need to be reduced to improve the reliability of the diagnosis.
New techniques
Electronic caries meters
Recent research has suggested that changes to the electrical impedance of enamel can indicate an active lesion. Small d.c. voltages have less resistance in carious enamel than that through an intact surface. The instrument needs a clean and dry surface to work efficiently and is generally used on the occlusal surfaces of molars and premolars. The advantage of using this technique is that it is the occlusal surfaces of molar and premolar teeth where radiographic assessment of caries is less accurate than the proximal surface. The tip of the probe is less than
DIAGNOdent
This technique, currently commercially available as an instrument called the DIAGNOdent (KaVo), utilizes the reflectivity of light from the tooth surface. The light reflectivity from a carious and non-carious surface is different. The instrument is calibrated to detect this difference and informs the operator through a read out (Fig. 4.11). Like the electronic caries meters, these instruments can overdiagnose caries and potentially confuse stained surfaces with carious ones. In addition, some restorative materials have shown similar fluorescent values to those of carious dentine and its application for the detection of secondary caries seems questionable. As a result, these instruments have also not seen wide usage.
Treatment
The treatment of carious teeth should be based on the needs of the child; the long-term objective should be to help the child to reach adulthood with an intact permanent dentition, no active caries, as few teeth restored as possible and a positive attitude toward their future dental health.
Restorative materials:
Amalgam. Its main advantage is that it is economical and simple to use. However, there is current concern over its safety. In Scandinavia, its use is banned in children, with concern over environmental issues rather than amalgam toxicity itself. It does seem prudent to avoid its use whenever possible, especially in the paediatric population where other materials may give sufficient longevity.
Glass ionomer cements (GIC). These consist of basic glass and acidic water-soluble powder; they set by an acid-base reaction between the two components. The cement bonds to enamel and dentine and releases fluoride to the surrounding tissues.
Resin-modified GIC. A hybrid of GIC/resin that retains significant acid-base reaction in its overall curing process to set in the dark. There are two setting reactions: the acid-base reaction between glass and polyacid and a light-activated, free radical polymerisation of methacrylate groups of the polymer. This material has some physical advantages over conventional GIC, together with its ability to ‘command set’.
Polyacid-modified composite resin (compomer). This contains either or both essential components of a resinmodified GIC but it is not water based and, therefore, no acid-base reaction can occur. They will not set in the dark and cannot strictly be described as GICs.
Composite resins. Their introduction revolutionised clinical dentistry and their aesthetic benefits are unquestioned. Problems of resistance to wear, water absorption and polymerisation contraction have restricted their use in the permanent posterior teeth and almost ruled them out of a role in caries management in posterior primary teeth. Nevertheless they do have clearly defined roles in the anterior teeth of both dentitions.
Preformed crowns. These preformed extracoronal restorations are essential in the restoration of grossly broken down teeth, primary molars that have undergone pulp therapy, hypoplastic primary and permanent teeth and teeth in those children at high risk of caries, particularly those having treatment under general anaesthesia.
Isolation
Adequate isolation is necessary for any restorative material to have a chance of success. Rubber dam isolation is the optimum and may necessitate local anaesthesia for the gingival tissues. Clamps should be secured individually with floss ligatures. Additional advantages of the rubber dam include airway protection, soft tissue protection and reduced risk of caries infection from saliva aerosol. In the absence of rubber dam, good moisture control can be achieved with cotton wool rolls, dry tips and saliva ejector.
Mechanical measures
• This refers to procedures specifically designed for and aimed at removal of plaque from tooth surface methods for cleaning tooth mechanically are:
1. Prophylaxis by dentist
2. Tooth brushing
3. Mouth rinsing
4. Use of dental floss or tooth picks
5. Incorporation of detergents foods in diet
6. Pit and fissure sealants
Dental prophylaxis
• Careful polishing of roughened smooth surface and correction of faulty restoration decreases the formation of bacterial plaque and there by reducing the development of new carious lesion
Tooth brushing
Types of tooth brushing
– Manual
– Powered
– Sonic and ultrasonic
– Ionic
ADA specification for a tooth brush
– 1-
– 5/16 – 3/8 inches in width
– 2 – 4 rows of bristles
– 5-12 tufts per row
Mouth rinsing
• Use of mouth wash for the benefit of its action in loosening food debris from teeth has been suggested to be of value as caries control measures.
Dental floss
• Dental flossing is effective in removing plaque and dislodge the irritating matter that is real source of disease.
• Used in type I gingival embrasures
It is available in:
– Multifilament – twisted / non twisted
– Bounded / unbounded
– Thick / thin
– Waxed / non waxed
Oral irrigators
– Use of flushing devices
– Irrigation devices composed of a built in pump and a reservoir
– It can also be used to deliver antimicrobial agents
Detergent foods
• Fibrous food in diet prevent lodging of food in pit and fissure and acts as detergent
Chewing gum
• Chewing gum tend to prevent caries by mechanical cleaning action
Pit and fissure sealants
• A sealant is a dental resin that is firmly bounded to enamel surface and isolates pit and fissure from caries producing conditions in oral environment
• Types:
1st generation – ultraviolet light activated
2nd generation – chemical activated
3rd generation – visible light activated
4th generation – fluoride containing
• Examples of pit and fissure sealants
• alphadent
• helioseal F
• helioseal
• Seal – rite
• baritone L3
• concise white sealant
• concise light cure white seal