Effects of sealant and self-etching primer on enamel decalcification. Part I: an in-vitro study

The objective of this study was to compare the resistance to enamel demineralization between self-etching primer (SEP) and conventional sealant in vitro.

A total of 120 molar sections were randomly assigned to 3 groups: SEP (Transbond Plus, 3M Unitek, Monrovia, Calif), sealant (Light Bond fluoride-releasing sealant, Reliance Orthodontic Products, Itasca, Ill), or control (no enamel treatment). SEP or sealant was applied following the manufacturer's recommendations. The tooth samples were exposed to rotary brushing for 2 minutes. A 2 x 2-mm window of sound enamel was created by using nail varnish. After 48 or 72 hours of acidic challenge with Ten Cate solution (pH 4.46), the samples were sectioned down to a thickness of 200 microm and stained with rhodomine B dye to evaluate lesions, lesion depths, area of lesions, and total fluorescence by using confocal microscopy. Statistical analyses were performed with 1-way analysis of variance (ANOVA) and Tukey-Kramer tests.

The incidence of lesion was 50% in the sealant group and 100% in both the SEP and the control group. The lesion in the sealant group was present only when the sealant integrity was broken. Lesion depth (149.9 +/- 20.5 microm), area (636 +/- 90 x 10(2) microm(2)), and total fluorescence (252 +/- 83 x 10(4)) in the SEP group were similar to those in the controls. Lesion depth (107.6 +/- 45 microm), area (441 +/- 212 x 10(2) microm(2)), and fluorescence (160 +/- 103 x 10(4)) in the sealant group were significantly less than in the SEP and control groups (P <0.05).

These results suggest that neither sealant completely protects the teeth against enamel decalcification. The application of sealant provided protection in 50% of the samples, whereas the SEP provided no resistance to enamel demineralization. Protection from acid demineralization depends on the integrity of the sealant.