Purpose: The effects of argon laser (AL) irradiation exposure and remineralizing solution (RS) treatment were evaluated alone and in combination on caries-like lesion formation in permanent tooth root surfaces in an in vitro study. Materials and Methods: Ten caries-free permanent tooth root surfaces were divided into 4 segments and each segment from each tooth was assigned to 1 of 4 treatment groups: no treatment control (n = 10), AL irradiation alone at 13.5 J/cm2 (0.270 W, 5-mm beam, 10 s, n = 10), RS treatment alone for 2 min (n = 10), and AL irradiation before RS treatment (n = 10). This allowed each tooth to serve as a matched internal control for each of the treatments. In vitro caries were created using a modified ten Cate solution. The longitudinal sections (3 per tooth segment, 30 per treatment group) were evaluated for mean lesion depth. Results: After lesion formation, mean lesion depths (± standard deviation) were 288 ± 32 μm for the no treatment controls, 198 ± 23μm for AL irradiation alone, 188 ± 19 μm for RS treatment alone, and 109 ± 14 μm for AL irradiation before RS treatment. All treatment groups had mean lesion depths that were significantly less than those for the matched no treatment control group (ANOVA, Duncan multiple range [DMR] test, p < 0.05). AL irradiation before RS treatment significantly reduced lesion depth compared with AL irradiation alone or RS treatment alone (ANOVA, DMR test, p < 0.05). Conclusion: Both AL and RS alone provided significant reductions in lesion depths for in vitro root surface caries compared with no treatment controls. However, the maximum reduction in caries-like lesion depth on permanent tooth root surfaces was achieved when the RS, containing calcium, phosphate, and fluoride in a carbopol base, was combined with AL irradiation.
Keywords: permanent teeth, root surface, caries, argon laser, calcifying solution, remineralization, demineralization, artificial caries