ACP Remineralizing Agents: Effect on In Vitro Enamel Caries

Objective: This in vitro study evaluated the effects of agents containing amorphous calcium phosphate with and without fluoride, and calcium-phosphate-fluoride on in vitro enamel caries initiation and progression. Methods: 15 teeth with sound enamel surfaces were divided into 4 portions. Each tooth portion was assigned to a treatment group: 1) No Treatment Control; 2) Relief ACP Oral Care Gel (ACP, potassium nitrate, sodium fluoride; Discus Dental Inc., Culver City, CA 90232); 3) Remin+ Gel (calcium, phosphate, fluoride; Denstply Raintree Essix Inc., Metraire, LA 70002); 4) MI Paste (ACP; GC America Inc., Alsip, IL 60803). The tooth portions were treated according to the manufacturers' guidelines, followed by synthetic saliva rinsing on a daily basis for 14 days. Control tooth portions were exposed only to synthetic saliva rinsing on a daily basis for 14 days. A modified ten Cate solution was used for in vitro enamel caries initiation (10 days) and progression (5 days). Each tooth portion was treated prior to lesion initiation and before lesion progression, as noted above. Longitudinal sections (5 per tooth portion for each treatment group) were taken after the lesion initiation period and the lesion progression period for polarized light study and statistical analysis (ANOVA, DMR). Results: Mean lesion depths were: Lesion Initiation Period: Control 278±27um; Relief 147±21um (P<.05); Remin+ 137±17um (P<.05); MI Paste 132±23um (P<.05). Progression Period: Control 397±41um; Relief 242±31um (P<.05); Remin+ 267±34um (P<.05); MI Paste 229±27um (P<.05). For both the lesion initiation and progression periods, significant differences were found between the control group and all treatment groups (P<.05). No significant differnces were found among the Relief, Remin+ and MI paste treatment groups (P>.05). Conclusions: The agents with ACP with fluoride (Relief) or without fluoride (MI Paste), and with calcium-phosphate-fluoride (Remin+) significantly reduced in vitro caries lesion depth during both lesion initiation and lesion progression periods compared with matched no treatment controls. The availability of calcium and phosphate to enamel undergoing in vitro demineralization may lessen the effects of a continuous artifical caries challenge. (Funded by Discus Dental Inc.)