Fissure sealing: Optimization of sealant penetration and sealing properties

Purpose: This in vitro study determined the penetration depth of a fissure sealant into an empty fissure system and into a conditioned enamel surface, using different sealing procedures. Materials and Methods: 48 extracted, n on-carious human molars were sealed with the unfilled sealant (Heliobond) u sing the enamel adhesive technique (35% phosphoric acid gel, 120 s etching time, bond application, light-curing for 60 s). The following factors were tested in comparison to the control group (1): influence of a precuring tim e lapse of 20 s after sealant application (2); ultrasound application with a plastic tip during the etching procedure (3); a wetting agent in an acid vehicle (4); enamel drying with acetone after the etching procedure (5); an d finally, the combination of ultrasound during etching; a drying procedure with acetone; and a 20 s precuring time lapse (all applied to the same sam ple). The sealed teeth were sectioned and evaluated by conventional light m icroscopy to determine the penetration depth into the fissure, and by confo cal laser microscopy to investigate the quality of the adhesion zone. Resul ts: Strict adherence to a specified penetration time, an intensified etchin g procedure with ultrasound, and the use of a drying procedure with acetone each showed a positive effect on the fissure penetration depth of the seal ant and on the adhesion zone. The combination of these measures improved si gnificantly the quality of the fissure sealing. Penetration depth increased to 92% of the fissure depth. From 95-100% of the total length of the analy zed adhesion zone shows excellent tags of sealant in the conditioned enamel surface.