Effects of Occlusal Loading on Microleakage of Fissure Sealants

Objectives: The aim of this study was to assess the effect of occlusal loading on the microleakage of glass ionomer and resin based fissure sealants. Methods: Thirty extracted sound human permanent third molars were divided into six groups of five teeth. In groups I, II and III glass ionomer fissure sealant, Fuji VII (GC, Japan) was placed, and in groups IV, V and VI resin based fissure sealant, Helioseal F (Ivoclar, Vivadent, Liechtenstein) was placed according to manufacturer's instructions. The specimens were thermocycled for 500 cycles at 5ºC and 55ºC with a dwell time of 30 seconds at each temperature prior to load application. Application of load was done on the central pit of the tooth as follows: groups I and IV: F=0N; groups II and V: F=400 N; groups III and VI: F = 800 N. The teeth were stored in distilled water for 24 hours, nail varnish was applied to within 1 mm of sealant margins, then specimens were immersed in 1% methylene blue solution for 24 hours. The teeth were sectioned buccal-lingualy at three locations and six slices of each tooth were examined using a stereomicroscope at magnification of 25X. Microleakage was scored as distance of dye penetration with 0 = no microleakage and 3 = microleakage to underlying fissure. Statistical analysis was carried out to find the significance of the results using chi-square test. Results:There were no statistically signifficant differences in mean dye penetration between two tested materials. The samples with load applied showed higher mean dye penetration. In groups II and V(F=400N) the difference was not statistically signifficant (p<0.2) and in groups III and VI(F=800N) the difference was statistically signifficant(p<0.05) compared to groups I and IV(F=0N). Conclusion:The data of this study indicated that occlusal loading have increased the microleakage of the sealant materials.