Effect of Environmental Pressure Changes on Microleakage to Restorative Materials

Objectives: To determine and compare the effect of environmental pressure changes during diving to the various types of restorative materials on microleakage.

Methods: Eighty conventional Class V cavities with the incisal and gingival margins in enamel were prepared in bovine incisor teeth. Teeth were randomly divided into four groups. Each group of twenty was randomly divided into two groups of ten, one group to act as control and the other as experimental. The restorative materials used were Filteks™ Z250 (3M Espe), Filteks™ P60 (3M Espe), Ketac Molar™ (3M Espe), Amalgam (Dispersalloy™, Dentsply). Each experimental specimen was subjected to thirty compressions cycle over a range of 0 to 50metre sea water depth (MSW) at a rate of 10meter per-minute in the hyperbaric chamber (Drass Galeazzi, Manufacturer). The chamber was held at 50metre sea water depth (MSW) for 5 minutes, and then decompressed over a 5 minute period. After the compressions cycle, the specimens were then immersed in 10% methylene blue for 24 hours at room temperature. The teeth were sectioned bucco-palatally at the mid line of the restoration. The site and degree of leakage of each section was scored using a scoring system under a stereomicroscope 15 times of magnifications.

Results: There is a significant difference in leakage extent (Chi-Square Test, p=0.001), between Ketac Molar experimental and control group.

Conclusion: Environmental pressure changes affected the microleakage of the cavities restored with Ketac Molar™ (3M Espe). Other restorations used in this study appeared to be unaffected by environmental pressure changes.