Surface topography and enamel-resin interface of pit and fissure sealants following visible light and argon laser polymerization: An in vitro study

This in vitro study compared the effects of visible light and argon laser p olymerization of pit and fissure sealants on surface topography and the ena mel-sealant interface. Twenty caries-free human molars and premolars underw ent soft tissue debridement and a fluoride-free prophylaxis. Fluoride-relea sing sealant (UltraSeal XT Plus, South Jordan, UT 84095) was placed on the occlusal surfaces per the manufacturer's instructions, but underwent either visible-light polymerization fur 30s (n=10), or argon laser polymerization (0.231J/cm(2)) for 10s (n=10). The sealed teeth were thermocycled (500 cyc les, 5 degrees to 50 degrees C) in artificial saliva. Surface morphology wa s evaluated by SEM. The teeth were sectioned for polarized light and SEM ev aluation of the enamel-sealant interface, with two sections per tenth prepa red for SEM. Phosphoric add was used to unmask the enamel-sealant interface with one section; while the other section was not exposed to the phosphori c add. Surface morphology of the sealant material was similar with both vis ible light and argon laser polymerization; however, there Lt as a tendency for occasional areas of mild, focal cratering of the sealant sur face with laser-curing. The unction between sealant and adjacent unsealed enamel was a relatively smooth transition without gays, microspaces, crazing, exfoliat ive changes, or microfractures with both visible Light and laser cured seal ants. Acid treatment of the sections revealed resin tags which extended int o the adjacent enamel for a considerable distance on SEM examination. The r esin tags were similar in length and morphology with both visible light and argon laser curing. The enamel-sealant interface with visible light and la ser curing showed intimate contact between the sealant and etched occlusal enamel with close apposition of the sealant. No microspaces were identified between the sealant and the occlusal enamel. An intact, interdigitating in terface between a sealant and the adjacent etched enamel provides the first line of defense against a cariogenic challenge. Visible-light and argon la ser curing allows for an intimate enamel-sealant interface without microspa ces and protects sealed enamel from cariogenic challenges. The benefit of a rgon laser polymerization, fluoride release and mechanical protection of se alant material may provide improved caries resistance in sealed pits and fi ssures and adjacent nonsealed enamel surfaces.