Effects of argon laser irradiation and acidulated phosphate fluoride on root caries.

PURPOSE

To determine the effects of argon laser irradiation (ArI) and topical acidulated phosphate fluoride (APF) treatment on artificial caries formation in root surfaces.

MATERIALS AND METHODS

After soft tissue debridement and fluoride-free prophylaxis, the teeth were divided into quarters and acid-resistant varnish was applied, leaving windows of sound root surface exposed. Each tooth received four separate treatments: (1) Control-mesiobuccal quarter; (2) ArI only--mesiolingual quarter; (3) ArI followed by APF- distobuccal quarter; (4) APF followed by ArI-distolingual quarter. ArI was for 10 seconds at 2W (100J/cm2) and APF treatment was for 4 minutes. After artificial lesion formation, sections were prepared and evaluated with polarized light. Mean lesion depths were determined and compared (ANOVA & DMR for a paired design).

RESULTS

Mean lesion depths were: 347 +/- 41 microns--controls; 263 +/- 32 microns--ArI only; 158 +/- 21 microns--ArI followed by APF; and 149 +/- 17 microns -APF followed by ArI. Lesion depths were significantly different (P < 0.05) between the control group and each treatment group, and between ArI only group and either combined APF and ArI groups. No lesion depth difference (P > 0.05) was present between the combined APF and ArI groups. Argon laser irradiation significantly enhanced the resistance of root surfaces to demineralization. Combination of APF treatment with argon laser irradiation provided added protection against a constant artificial caries attack.