Lecture 4: Dental Caries PDF

Dental Caries 1  Definition Dental caries is defined as a microbiological disease of the hard structure of teeth, which results in localized demineralization of the inorganic portion and destruct on of the organic substances of the tooth. Sites Of Dent...

Dental Caries 1  Definition Dental caries is defined as a microbiological disease of the hard structure of teeth, which results in localized demineralization of the inorganic portion and destruct on of the organic substances of the tooth. Sites Of Dental Caries: ▪ Pits and fissures on occlusal surfaces of molars and premolar. ▪ Buccal pits of molars ▪ Palatal pits of maxillary incisors ▪ Enamel of the cervical margin of the tooth just coronal to the gingival margin ▪ Proximal enamel smooth surfaces apical to the contact point ▪ In teeth with gingival recession occurring because of periodontal disease ▪ The margins of restorations predominantly which are deficient or overhanging 2 ▪ Tooth surfaces adjacent to dentures and bridges. ‫ذ‬ ‫‪3‬‬  Possible interventions Etiology of Dental Caries Reduce Strep. mutans Possible interventions numbers by: Reduce intake of cariogenic Reduction in sugar intake sugars Particularly sucrose Active or passive immunization Diet Bacteria Caries Possible interventions Susceptible Water + other types of Time Surface Fluoridation Possible interventions (Host) Prevention during post- eruptive maturation Avoid frequent sucrose intake (snacking) Fissure sealing Properly4 contured Stimulate salivary flow restorations + sugar clearance  Etiology of Dental Caries Plaque Acidogenic Enzymes Food Acids Tooth Carious Bacteria Lesions  Theories Of Dental Caries 1. Acidogenic theory 2. Proteolytic theory 3. Proteolysis-chelation theory. Acidogenic Theory: ✓ 1890 ✓ WD Miller ✓ dental decay is a chemoparasitic process consisting of 2 stages 1. decalcification of enamel results in total destruction decalcification of dentin as a preliminary stage 2. followed by dissolution of softened residue of enamel and dentine 6 Factors that causes decay: 1. Role of carbohydrates 2. Role of microorganisms 3. Role of acids 4. Role of dental plaque Role of Carbohydrates: Carbohydrates exert cariogenic effect which depends upon the following factors: 1. Frequency of intake 2. Chemical composition, for example, monosaccharides and disaccharides are more carious than polysaccharides 3. Physical form like solid, sticky jelly like or liquid 4. Time of contact of carbohydrate with the tooth 5. Presence of other food components like presence of high fat or proteins makes carbohydrate less cariogenic. 7  Role of microorganisms ❖ Caused by acid resulting from action of microorganisms on carbohydrates ❖ S. mutans has been proved for the initiation of caries Initiation of Dental Caries Progression of Dental Caries Streptococci Streptococcal species: S. mutans Streptoccal species in deep S. milleri dentinal caries and root S. mitior caries S. sanguis S. salivaris Lactobacilli Lactobacilli in dentin L. acidophillus L. acidophillus L. casei L. casei Actinomycoses Actinomycoses A. viscosus A. Israeli A. naeslundii A. odontolyticus 8 Role of acids ✓ play most important role in pathogenesis of dental caries ✓ pH 5.5 is called critical pH ✓ Below this pH demineralization of tooth substance begins found on uncleaned tooth surfaces ✓ appear as tenacious, thin film ✓ may accumulate within 24-48 hours Role of dental plaque: Dental plaque also known as microbial plaque is important for beginning of caries because it provides the environment for bacteria to form acid, which causes demineralization of hard tissue of teeth. 9  Proteolytic Theory ❖proteolysis of the organic components of tooth as an initial process ❖ than actual demineralization + dissolution of inorganic substances ❖ proposed that enamel lamellae or rod sheath (proteins) may be lysed ❖which means proteolysis as first event in further progression of bacterial invasion + demineralization carious lesions Proteolysis Chelation Theory: suggests that caries is caused by simultaneous events of proteolysis + chelation Proteolysis destruction of organic portion of tooth by proteolytic microorganisms Chelation: removal of calcium by forming soluble chelates ❖ oral bacteria attack organic component of enamel (proteolysis) breakdown products have chelating ability and this dissolves tooth minerals 10 11  Local Factors Affecting The Incidence Of Caries Tooth (Host): ✓ Variation in morphology ✓ Composition ✓ Position. Substrate (Environmental factors) ❑ Saliva i. Composition ii. Quantity iii. pH iv. Viscosity v. Antibacterial factors. 12 ▪ Diet i. Physical factors ii. Local factors a) Carbohydrate content: Presence of refined cariogenic carbohydrate particles on the tooth surface b) Vitamin content c) Fluoride content. d) Fat content Microorganisms: Most commonly seen microorganisms associated with caries are Streptococcus mutans and Lactobacillus. Time period. 13 14 15  Classification 1. Depending on nature of attack 2. Depending on progression of caries 3. Depending on surfaces involved 4. Based on direction of attack 5. Based on number of surfaces involved. 6. GV Black Classification based on treatment and restoration design 7. Based on location of lesion 8. Based on tissue involved 16 (1) Nature of Attack ❑ Primary Caries ✓ incipient; initial ✓ first attack on tooth surface Secondary Caries ✓ recurrent ✓occurs on margins or walls of existing restorations 17  (2) Progression of Caries Acute ✓ rapidly invading process ✓ involves several teeth ✓ lesions are soft + light colored Acute ✓ usually pulp is involved at early stage Rampant caries Nursing bottle caries Radiation caries Chronic ✓ lesions are long standing ✓ fewer in number 18  (3) Surfaces involved Pit and fissure Smooth surface caries (4) Direction of caries attack Forward Caries ✓ proceeds from enamel to dentin ✓ lesion is triangle in shaped with base of triangle at enamel surface + apex towards dentin ✓ in pits + fissures base is at DEJ 19 + apex is in the pit OldDirection (4) Theories of caries attack Backward Caries ✓ proceeds from DEJ towards enamel surface ✓ also triangle shaped with base at DEJ + apex towards enamel surface 20 OldNumber (5) Theories of Surfaces involved Simple ✓ only one surface is involved by caries Compound ✓ 2 surfaces are involved Complex ✓ more than 3 surfaces involved 21  OldGV (6) Theories Black Classification Class I ✓ begin in pits, fissures +defective grooves ✓ seen in occlusal surface ✓ occlusal two-thirds of molars ✓ lingual pits of incisors 22 OldGV (6) Theories Black Classification Class II ✓ lesions seen on proximal aspects of molars + premolars 23 OldGV (6) Theories Black Classification Class III ✓ lesions involving proximal aspects of incisors ✓ do not involve or necessitate removal of incisal edge 24 OldGV (6) Theories Black Classification Class IV ✓ lesions involving proximal aspects of incisors ✓ involve or require removal of incisal edge 25 OldGV (6) Theories Black Classification Class V ✓ lesions present on gingival third of all teeth 26  OldGV (6) Theories Black Classification Class VI ✓ lesions found on incisal edges + cusp tips 27 OldLocation (7) Theoriesof the lesion Pit and Fissure caries ✓ Occlusal ✓ Buccal or lingual pit Smooth surface caries ✓ Proximal ✓ Buccal or Lingual surface Root caries 28 29  OldTissue (8) Theories involved Enamel Caries Dentinal Caries Cemental Caries Classification Senile Caries ✓ caries associated with aging ✓ almost exclusively seen on root surface Residual Caries ✓ not removed during restorative 30 procedure  Clinical Features: Smooth Surface Caries Interproximal Caries ✓ opaque chalky region (white spot) ✓ some cases yellow or brown pigment area ✓ spots are generally located on outer surface of enamel between contact point + height of free gingival margin ✓as caries penetrates enamel, enamel surrounding the lesion assumes bluish white appearance usually apparent as laterally spreading caries at DEJ ✓ common for proximal caries to extend both bucally + lingually 31 Cervical, Buccal, Lingual or Palatal Caries Clinical Features: ✓ usually extends from area opposite gingival crest occlusally to convexity of tooth surface ✓ extends laterally towards proximal surfaces ✓usually occurs on cervical area typical cervical lesion is a crescent shaped cavity beginning as slightly roughened chalky area ✓ gradually becomes excavated 32 Pit and Fissure Caries Clinical Features: ✓ appears brown or black ✓ feel slightly soft ✓ catch a fine explorer point ✓ enamel bordering the pit and fissure may appear opaque as it becomes bluish white undermined 33 Pit and Fissure Caries Clinical Features: ✓ lateral spread of caries at DEJ as well as penetration into dentin along dentinal tubules may be extensive ✓ without fracturing away overhanging enamel ✓ there may be large carious lesion with only a tiny point of opening 34 Pit and Fissure Caries 35 Root Caries ✓ also known as cemental caries ✓ involves both dentin + cementum ✓ in number of people exhibiting gingival recession with clinical exposure of cemental surface. ✓slowly progressing chronic lesion ✓ usually found in mandibular molar area + premolar region ✓ gingival recession is associated with root surface caries 36 Recurrent Caries ✓ occurs immediately adjacent to restoration ✓ may be caused by inadequate extension of restoration ✓ was not able to excavate or removed well original carious lesion. ✓restoration with poor margins permitted leakage + entrance of both bacteria + substrate 37 Nursing Bottle Caries Etiology: ✓ due to nursing bottle containing milk or milk formula, fruit juice or sweetened water ✓ sometimes it occurs due to sugar or honey-sweetened pacifier Pathogenesis: ✓ child is put on bed at afternoon nap time or at night with nursing bottle containing milk or a sugar containing beverage ✓ milk or sweetened liquid becomes pooled around maxillary anterior teeth ✓carbohydrate containing liquid provide an excellent 38 culture medium for acidogenic microorganisms Nursing Bottle Caries Clinical Feature: ✓ prolonged feeding beyond usual time may result in early + rampant caries ✓ early carious involvement of maxillary anterior, maxillary + mandibular 1st permanent molars, mandibular canines. ✓carious process is so severe that only root stumps remain 39  Nursing Bottle Caries Prevention: ✓ parent should start brushing the child teeth as soon as they erupt in oral cavity ✓ discontinue bottle feeding as soon as child can drink from a cup, at approximately 12-15 months of age 40 Rampant Caries suddenly appearing widespread resulting in early involvement of pulp Etiology: ✓ may be due to nutritional deficiency ✓ malnutrition ✓emotional disturbances Clinical Features: ✓ occurs in children with poor dietary habits ✓ extensive inter-proximal + smooth surface caries 41 Arrested Caries Clinical Features: ✓ both deciduous + permanent are affected ✓ large open cavities ✓ brown-stained polished appearance + hard 42  Zones in Enamel Caries ❑ Zone 1: Translucent zone ✓ Represent the advancing front of the lesion ✓ Ten times more porous than sound enamel ✓ Not always present. ❑ Zone 2: Dark zone ✓ It lies adjacent and superficial to the translucent zone ✓ Usually present and thus referred as positive zone ✓ Called dark zone because it does not transmit polarized light ✓ Formed due to demineralization. ❑ 43 ❑ Zone 3: Body of the lesion ✓ Largest portion of the incipient caries ✓ Found between the surface and the dark zone ✓ It is the area of greatest demineralization making it more porous. ❑ Zone 4: Surface zone: ✓ This is zone is not or least affected by caries ✓ Greater resistance probably due to greater degree of mineralization and greater fluoride concentration ✓ It is less than 5 percent porous ✓ Its radiopacity is comparable to adjacent enamel. 44  Zones of Dentinal Caries ❑ Zone 1: Normal dentin ✓ Zone of fatty degeneration of Tome’s fibers ✓ Formed by degeneration of the odontoblastic process ✓ Otherwise dentin is normal and produces sharp pain on stimulation. ❑ Zone 2: Zone of dentinal sclerosis ✓ Intertubular dentin is demineralized ✓ Dentinal sclerosis, i.e. deposition of calcium salts in dentinal tubules takes place ✓ Damage to the odontoblastic zone process is apparent ✓ There are no bacteria in this zone. Hence, this zone is capable of remineralization. 45 ❑ Zone 3: Zone of decalcif cation of dentin ✓ Further demineralization of intertubular dentin lead to softer dentin. ❑ Zone 4: Zone of bacterial invasion ✓ Widening and distortion of the dentinal tubules which are filled with bacteria ✓ Dentin is not self-repairable, because of less mineral content and irreversibly denatured collagen ✓ This is zone should be removed during tooth preparation. 46 ❑ Zone 5: Zone of decomposed dentin due to acids and enzymes ✓ Outermost zone ✓ Consists of decomposed dentin filled with bacteria ✓ It must be removed during tooth preparation. 47