Dental Cariology PDF

Dental caries is defined as a progressive irreversible microbial disease affecting the hard parts of tooth exposed to the oral environment, resulting in demineralization of the inorganic constituents and dissolution of the organic constituent, thereby leading to a cavity formation. Cariology: Mode...

Dental caries is defined as a progressive irreversible microbial disease affecting the hard parts of tooth exposed to the oral environment, resulting in demineralization of the inorganic constituents and dissolution of the organic constituent, thereby leading to a cavity formation. Cariology: Modern restorative dentistry is now shifting from the conventional drill and fill concept in managing caries, to full recognition of this disease as being infectious condition with causative factors, signs and symptoms, preventive and therapeutic measures. Dental caries: It is a multifactorial, transmissible, infectious microbiological disease caused primarily by the complex interaction of cariogenic oral flora ( biofilm) with fermentable dietary carbohydrates on the tooth surface over time. It is a dynamic process and resulting in disturbance in the equilibrium between the tooth substance and the dental plaque fluid, finally resulting in a loss of minerals from the tooth surface. Etiology of dental caries Ecology: Is the science that studies the interaction between organisms and their environment. Ecosystem: It is a circumscribed area occupied by a biological community. Ecological niche: It is the combination of food and shelter for the micro-organisms. Contributing factor of dental caries - Dental caries is a multifactorial disease in which there is an interplay of 3 principle factors. I. host ( teeth, saliva etc.) II. Micro flora III. Substrate (diet) - In addition the fourth factor, time must be considered. Modified Keyes – Jordan diagram I- Dental plaque (pellicle & bacteria) It is an adherent deposit of bacteria and their products on tooth surface. Oral environment - Clean enamel surface Amorphous organic film (pellicle). It consists mainly of glycoprotein precipitated from saliva. It is very tenacious and can attract bacteria to the tooth surface (streptococci). Role of bacteria: Streptococci and lactobacilli. Acidogenic Aciduric Adhere to the tooth surface. Synthetize sticky extracellular polysaccharide from the dietary sugar. It is mainly polymers of glucose. It gives the matrix of dental plaque its gelatinous consistency. It helps bacteria to stick to each other and to the tooth. It thickens the layer of plaque. It prevents saliva from neutralizing plaque acids. II- Role of dietary carbohydrate: Not all carbohydrate are equally cariogenic. Complex carbohydrates such as starch are relatively harmless. low molecular weight carbohydrates (sugar) diffuse rapidly into plaque and are metabolized quickly by bacteria. Many sugar containing foods and drinks cause a rapid drop in plaque pH to a level which can cause demineralization of enamel. The synthesis of extracellular polysaccharide from sucrose is more rapid than from glucose, fructose, and lactose. - Oral carbohydrate clearance: Carbohydrate concentration and the length of time they remain in the mouth during and after eating are essential factors. Foods are eliminated during and after mastication by: 1. The rinsing effect of saliva. 2. The activities of the masticatory muscles. 3. The activities of tongue, lips, and cheeks. The clearance time may be prolonged by: 1. Retentive factors in the dentition (cavities, poor filling, etc.). 2. Low salivary flow. 3. Viscous saliva. Stephan curve Showing sudden decrease in plaque ph following glucose rinse, which returns to normal after 30–60 min. Net demineralization of dental hard tissues occurs below the critical ph (5.5), shown in yellow III- The host: 1- tooth surface: which favor plaque retention are prone to decay, these sites are: Enamel pits and fissures. Smooth surface cervical to the contact area. The cervical margins of the tooth just coronal to the gingival margins. An exposed root surface duo to gingival recession. Deficient or overhanging margins of restorations. Surfaces adjacent to dentures and bridges. 2- Environment of the tooth (saliva and fluoride): - Salvia maintains the normal flora through Bacterial clearance: Salivary flow has a flushing effect to remove microorganisms which are not adherent to the oral surfaces. Direct anti bacterial activity: Salivary glands produce antimicrobial proteins that have a broad spectrum activity on microorganisms. The oral flora developed resistance to most of those protein rendering them less effective in caries inhibition. Buffering activity: Saliva has a buffering capacity, through its bicarbonate ion content, which reduce the potential for acid formation. Remineralization: Saliva is supersaturated with calcium ions which provide constant opportunity for remineralizing enamel. The remineralizing capacity of saliva is enhanced in the presence of fluoride ions. - When salivary flow decreased, the food retention increases and the buffering action of saliva decreases. IV- Time: The carious process consists of alternating periods of destruction and repair. The lesion arrest is a result of mechanical removal of cariogenic plaque exposing the tooth to saliva for the re-deposition of dissolved minerals. Enamel, dentin, and cementum are highly dynamic tissues exposed to constant supply of ions leading to re-preciptation of minerals. External supply from the oral cavity. Internal supply through the pulp.  Epidemiology of dental caries - The classic DMF (decay/missing/filled) index is one of the most common methods for assessing caries prevalence as well as dental treatment needs among populations. This index is based on in-field clinical examination of individuals by using a probe, mirror and cotton rolls. Because the DMF index is done without X-ray imaging, it underestimates real caries prevalence and treatment needs. Classification of dental caries 1) Chronology 2) Tissue affected 3) Anatomical site 4) Surfaces to be restored 5) Number of tooth surface involved 6) Whether it is a new lesion or recurrent 7) Whether caries is completely removed or not 8) Activity of carious lesion 9) Speed of caries progression 10)Pathway of caries spread 11)Severity 12)WHO system classification 13)Radiographic classification 14)Black’s classification 15) Mount & Hume (Si/Sta) classification 16)Visual classification 17) ICDAS classification 1- Chronology The number of new lesions occurring in a year, shows three peaks at the ages 4-8,11-19 and 55-65 years 1. Early childhood caries 2.Adolescent caries 3.Adult caries Early childhood caries - Early childhood caries would include, two variants: Nursing caries and rampant caries. - The difference primarily exist in involvement of the t e et h [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 - Cause : cariogenic semisolid food + lack of oral hygiene Type II (moderate) - Unaffected mandibular incisors - Soon after first tooth erupts - Cause  inappropriate feeding +lack of oral hygiene Type III (severe) All teeth including mandibular incisors - Cause  multitude of factors  Nursing caries Rampant caries - Seen in infant and toddler - Seen in all ages, including adolescence - Affects primary dentition - Affects primary and permanent dentition - Mandibular incisors are not involved - Mandibular incisors are also affected - etiology - Multifactorial - etiology 1. Frequent snacks 1. Improper bottle feeding 2. Sticky refined CHO 2. Pacifier dipped in honey/other sweetener 3. Decreased salivary flow 4. Genetic background adolescent caries (Teenage 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 t ype ,with a small enamel opening. - The presence of a large pulp chamber adds to the condition ,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. 2- tissue affected Enamel Dentin Cementum 3- anatomical site 4- surfaces To be restored 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. 5- number of tooth surface involved - Simple: A caries involving only one tooth surface - Compound: A caries involving two surfaces of tooth - Complex: A caries that involves more than two surfaces of a tooth 6- whether it is a new lesion or recurrent (virginity of The lesion) - Initial/Primary caries (unrestored surfaces) - Recurrent / Secondary (adjacent to filling) 7- whether caries is completely removed or not During treatment - Residual (demineralized tissue left in place before a filling is placed) 8- activity of carious lesion Active (progressive lesion) Inactive / Arrested ( lesion that may have formed earlier and then stopped) 9- speed of caries progression - Acute caries Chronic caries Rapid Slow Soft dentin Hard Large flakes Difficult in excavation Light in color Dark Painful Several teeth Bad oral hygiene Deepest layer (affected by acids) 10.based on pathway of caries spread 1. forward caries 2. backward caries Cone in E ≥ cone in Caries in DEJ exceed the adjacent caries in E - 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. 11- severity 12.world health organization (Who) system 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 13- radiation caries - Radiography is frequently associated with xerostomia due to decreased salivary secretion, an increase in viscosity and low pH - Three types of defects due to irradiation 1. Lesion usually encircling the neck of teeth amputation of crowns may occur 2. Begins as brown to black discoloration of tooth occlusal surface and incisal edges wear away 3. Spot depression which spreads from any surface