Argon Laser and Remineralizing Paste/Dentifrice: In Vitro Enamel Caries

Objectives: In vitro enamel caries formation in permanent teeth was evaluated to determine effects of argon laser (AL), dual treatment with remineralizing paste and dentifrice with fluoride alone and in combination with argon laser.

Methods: Caries-free permanent teeth (n=10) underwent debridement and a fluoride-free prophylaxis. Specimens were sectioned into quarters, and acid-resistant varnish was placed with 2 sound enamel windows exposed on each quarter. Each quarter was assigned to treatment group: 1) No treatment control; 2) AL exposure (13.5 J/cm², 270 mW, 5mm beam, 10s); 3) dual treatment with fluoridated remineralizing paste (RPFl) for 120s [MI Plus Paste, GC Corp], followed by fluoridated tricalcium phosphate (TCPFl) for 120s (Clinpro 5000, 3M-ESPE); 4) AL followed by dual RPFl/TCPFl treatment. Treated quarters were rinsed in distilled/deionized water, and exposed to synthetic saliva (24h). In vitro caries were created using an acidified gel (pH 4.25, 42d). Longitudinal sections (3/tooth quarter, 60/group) were evaluated for mean lesion depths (water imbibition, polarized light, ANOVA, DMR).

Results: Mean lesion depths were 347±42µm for No Treatment Control; 242±28µm for AL alone; 176±22µm for RPFl/TCPFl alone; and 109±31µm for AL followed by RPFl/TCPFl. All treatment groups had mean lesion depths significantly less than No Treatment Control (P<.05). Both dual treatment groups (RPFl/TCPFl, and AL followed by RPFl/TCPFl) had significantly decreased mean depths compared with the AL alone treatment group. AL followed by RPFl/TCPFl group had a mean depth significantly less than RPFl/TCPFl without AL treatment group (P<.05).

Conclusions: Dual treatment with remineralizing paste followed by remineralizing dentifrice provided significant caries protection for enamel when compared with argon laser irradiation alone and no treatment control groups (P<.05). Argon laser irradiation followed by dual treatment with remineralizing paste and dentifrice containing bioavailable calcium/phosphate and fluoride significantly enhanced in vitro enamel caries resistance (P<.05).