Dental calculus, both supra- and subgingival occurs in the majority of adults worldwide.
Dental calculus is calcified
dental plaque, composed primarily of
calcium phosphate mineral salts deposited between and within remnants of formerly viable microorganisms. A viable
dental plaque covers mineralized
calculus deposits. Levels of
calculus and location of formation are population specific and are affected by
oral hygiene habits, access to professional care, diet, age, ethnic origin, time since last dental cleaning, systemic disease and the use of prescription medications. In populations that practice regular
oral hygiene and with access to regular professional care, supragingival
dental calculus formation is restricted to tooth surfaces adjacent to the salivary ducts. Levels of supragingival
calculus in these populations is minor and the
calculus has little if any impact on oral-health. Subgingival
calculus formation in these populations occurs coincident with
periodontal disease (although the
calculus itself appears to have little impact on attachment loss), the latter being correlated with
dental plaque. In populations that do not practice regular hygiene and that do not have access to professional care, supragingival
calculus occurs throughout the dentition and the extent of
calculus formation can be extreme. In these populations, supragingival
calculus is associated with the promotion of
gingival recession. Subgingival
calculus, in "low hygiene" populations, is extensive and is directly correlated with enhanced
periodontal attachment loss. Despite extensive research, a complete understanding of the etiologic significance of subgingival
calculus to
periodontal disease remains elusive, due to inability to clearly differentiate effects of
calculus versus "plaque on
calculus". As a result, we are not entirely sure whether subgingival
calculus is the cause or result of periodontal
inflammation. Research suggests that subgingival
calculus, at a minimum, may expand the radius of plaque induced periodontal injury. Removal of subgingival plaque and
calculus remains the cornerstone of periodontal
therapy.
Calculus formation is the result of petrification of
dental plaque biofilm, with
mineral ions provided by bathing saliva or crevicular fluids. Supragingival
calculus formation can be controlled by chemical mineralization inhibitors, applied in
toothpastes or mouthrinses. These agents act to delay plaque calcification, keeping deposits in an amorphous non-hardened state to facilitate removal with regular hygiene. Clinical efficacy for these agents is typically assessed as the reduction in
tartar area coverage on the teeth between dental cleaning. Research shows that topically applied mineralization inhibitors can also influence adhesion and hardness of
calculus deposits on the tooth surface, facilitating removal. Future research in
calculus may include the development of improved supragingival
tartar control formulations, the development of treatments for the prevention of subgingival
calculus formation, the development of improved methods for root detoxification and
debridement and the development and application of sensitive diagnostic methods to assess subgingival
debridement efficacy.