Improving fissure sealant quality: mechanical preparation and filling level

Objective: To assess the effect of different modes of fissure preparation and filling level on the quality of pits and fissure sealants. Methods: Various modes of fissure preparation in combination with two filling levels were examined. A total of 90 caries-free extracted human molar teeth were divided into three groups according to fissure preparation: (a) no mechanical preparation; (b) mechanical preparation with a round carbide bur; and (c) mechanical preparation with a tapered fissure diamond bur. All fissures were acid-etched and each group was subdivided according to filling level, either to the border or overfilled, using Helioseal (Vivadent, Schaan, Lichtenstein) as a sealant material. A modified microleakage assay was performed, combining occlusal loading and thermocycling, prior to staining with 0.5% Basic Fuchsin. After sectioning, teeth were examined and photographed in a reflected light microscope, sealant retention was observed and recorded. Microleakage and sealant penetration depths were measured for each section. Two-way ANOVA was used for statistical analysis. Results: Sealant penetration and retention were significantly improved by mechanical preparation compared to non-prepared fissures (p<0.0001), and preparation with a tapered fissure diamond bur was superior to the round carbide bur. Overfilled fissures caused significantly higher levels of microleakage (p<0.004). Conclusions: Based on the results of this in vitro study, it is suggested that fissure sealant quality may be improved by mechanical preparation, preferably with a tapered diamond bur, and filling just to the border. Overfilling of fissures should be avoided.