Zinc in the mouth, its interactions with dental enamel and possible effects on caries; a review of the literature

Abstract

Zinc is an essential trace element. In the mouth, it is present naturally in plaque, saliva and enamel. Zinc is formulated into oral health products to control plaque, reduce malodour and inhibit calculus formation. It has good oral substantivity, and elevated concentrations can persist for many hours in plaque and saliva following delivery from mouthrinses and toothpastes. Although low concentrations of zinc can both reduce enamel demineralisation and modify remineralisation, during caries clinical trials, the addition of zinc to fluoride toothpastes has not affected their ability to reduce caries. Mechanistic studies may help explain this apparent contradiction. Zinc is readily desorbed from hydroxyapatite by calcium, which is plentiful in plaque and saliva. Where crystal-growth sites remain occupied by zinc despite this, they may simply be 'over-grown' by remineralisation initiated at unoccupied sites. Further, under certain conditions, low concentrations of zinc can enhance remineralisation of enamel lesions, by retarding lesion arrestment. Although this may help to explain the apparent lack of an overall zinc effect on caries, it seems unlikely that any negative effects would be countered exactly by positive effects. Further mechanistic studies, complementing well-designed in vitro and in situ caries studies, should lead to further understanding of the zinc-enamel interactions relevant to demineralisation and remineralisation.

Biochemical Indicators of Dental Caries in Saliva: An in vivo Study

“…Zinc is implicated in biomineralization, where it stimulates bone growth and mineralization and influences osteoclast activity. Increased caries incidence was reported when rats were fed a zinc-deficient diet [Lynch, 2011].…”

Evidence of an in vitro Coupled Diffusion Mechanism of Lesion Formation within Microcosm Dental Plaque

“…The forefront of caries research therefore remains in investigating systems integrate physiochemical information within a biological context [Cochrane et al, 2010;Lynch, 2011;Rao and Maihotra, 2011;Robinson, 2011], a feat which when applied in situ is generally confounded by a high degree of interindividual variation [Larsen et al, 1999;Sullivan et al, 1995]. Exploring the effects of agents that modulate biofilm cariogenicity in vitro is therefore an attractive alternative, and in this sense the constant-depth film fermenter (CDFF) has emerged as a powerful tool to meet the needs of current in vitro research.…”

Comparative Evaluation of Efficacy of Two Commercially Available Herbal and Allopathic Dentifrice on Dentinal Hypersensitivity and Their Effect on Plaque and Gingivitis.

“…16 Yashada bhasma contains zinc and has been formulated into oral health products to control plaque, reduce malodor and inhibit calculus formation. 17,18 In the present study dentinal hypersensitivity was reduced in allopathic dentifrice group during 7 days assessment whereas after 30 days herbal dentifrice group showed significant reduction in dentinal hypersensitivity. This means that desensitizing affect was maintained even 7 days after discontinuing the product in herbal dentifrice group, this might be due to the component Spinacia oleracea present in HiOra K group.…”