Calculus Hanadi Baeissa Hanadi Baeissa Dental calculus a

Calculus Hanadi Baeissa

Hanadi Baeissa

Dental calculus a) Supragingival • • • b) Subginival • Harder Friable Readily removed by scaling • Coloured (often green) Unpigmented • Present in smaller deposits, Form in greatest amounts on the lower incisors & upper which are not localized near molars i. e. near the orifices of the salivary ducts the main salivary ducts • Composition less site Composition varies in dependent different sites • non-salivary (serum) origin Salivary origin

Composition of Supragingival Calculus Inorganic (~ 80%) Organic (~ 20%) • Derived from saliva & bacteria • Brushite Ca. HPO 4. 2 H 2 O detectable in all deposits after 14 days of development - Largely protein with carbohydrate attached (12 -20%) - GAG (CS, HA & HS) from the Octa calcium Wetlockite Ca 3 (PO 4)2 gingivae phosphate With some magnesium -Lipids (3%) perhaps bacterial Ca 8 (HPO 4)2 (PO 4)4 Instead of calcium origin Especially in the presence Of fluoride apatite

Composition of Supragingival Calculus ( continue) F¯ is also present at ≤ 400 ppm (more in old calculus) n Many filamentous bacteria is present (example: leptotrichia buccalis) n Formation is intermittent n

Theories of calculus formation: 1. 2. Carbon dioxide loss: CO 2 loss from saliva, as it equilibrates with low CO 2 tension in the month ppt of calcium salts p. H change by ammonia formation: Urea NH 3 p. H, thus favoring ppt of calcium phosphate

3. The phosphatase theory: Bacterial pyrophosphatase PPi 2 Pi mineralization of plaque not much evidence to this 4. encourage Seeding theory: A seeding process calculus This does not explain individual variations in formation

Steps in calculus formation n Two stages 1. Matrix deposition (derived from plaque) Mineralization: reason unknown yet but provision of seed by plaque or bacteria is likely (mainly filamentous bacteria) 2.

Notes: Calculus is higher in smokers. v There is variation between different people in amount of calculus formed v First stage of calculus formation (matrix deposition) occurs readily in both slow and rapid calculus formers v The difference lies in the power to mineralize the matrix v

Possible factors effecting calculus formation 1. Differences in plaque a) composition: - increase Ca & P more mineralization - decrease methyl pentose & hexosamine b) increased rate of plaque formation in heavy calculus formers - therefore, the early stages, rather than the mineralization , differed in the two groups

2. Differences in saliva composition: q increase protein, Ca & phosphate calculus increase activities of acid phosphatase, pyrophosphatase, esterase more calculus increase urea more calculus increase lysozyme activity less calculus presence of low molecular weight protein adsorbed to apatite & might act as seed calculus q q

q q 3. The acidic protein of saliva said to prevent Ca ppt is either deficient or more rapidly broken down by bacteria calculus High viscosity of saliva less calculus Smoking leads to increased formation

Periodontal Disease Two most frequently occurring forms: 1 - Gengivitis • Limited to the gingival or soft tissues, surrounding the teeth • Results in bleeding of gums, and possibly change in color, shape, size, surface texture and consistency • Reversible on restoration of hygiene, does not result in destruction of tissues supporting the teeth 2 - Periodontitis • Extension of the inflammatory process from the gingival to the supporting periodontal tissue & destruction of these tissues • Can be controlled but not reversed • Chronic peridontitis result in loss of bone supporting the teeth mobility tooth loss

The effect of plaque on the gingivae It was first thought that calculus caused gingivitis n Volunteers not brushing for days developed gingivitis without calculus formation n Conclusion: Old plaque (> 48 hours) periodontal disease, but calculus help by providing mechanical irritation n

The nature of toxins in plaque causing Gingivitis Plaque contains substances which diffuse into the gingival tissues and irritate them: ex. n Proteolytic enzymes from bacteria release of a. a broken amines + ammonia, down H 2 S and mercaptans (all potential irritants) n

Plaque antigens such as bacterial endotoxins, enter the gingival and induce antibodies in the local lymph tissues. n The interaction between antibodies & antigens is beneficial, but it activates complement which in turn causes the release of substances contracting the smooth muscles of arterioles and increasing vascular permeability (cytokines edema) n

n This is part of the inflammatory response destruction of bone and periodontal fibers