In vitro remineralisation of eroded enamel lesions by saliva

Objectives: It is speculated that saliva, with its mineral content, may possess a reparative effect on an early erosion which is characterised by softened surface and slight subsurface demineralisation in addition to a crater. This study aimed to determine the possible remineralisation of early enamel erosion by saliva. Methods: Eroded lesions were produced in bovine incisors by 1-h immersion in orange juice. Control sections and three experimental slabs were produced from each tooth. The three slabs were assigned randomly to one of three remineralising agents: clarified natural saliva (NS), artificial saliva (AS) and remineralising solution (RS). All solutions had a pH of 7.2, a fluoride concentration of 0.022 ppm, and were changed daily. NS was collected daily from the same individual at the same time of day. The specimens were exposed to their respective remineralising agents for 28 days. Using microradiography and image analysis, the mineral loss (Δz) and lesion depth (ld) were quantified in sections cut from the control and experimental slabs. Results: A significant (p<0.001) amount of mineral was gained following exposure to each remineralising agent. Significantly less Δz and ld were observed for the experimental groups compared with the control group (p<0.001; paired t-test). This effect was greatest with RS and least with AS. Inter-group comparison (Duncan multiple tests) showed no significant difference in Δz among the experimental groups, however ld was significantly higher for AS (p<0.001) compared with RS and NS, and no difference was observed between RS and NS. Conclusion: Saliva as well as remineralising solutions can remineralise early enamel erosion.