Isfahan University of Medical SciencesDental Research Journal1735-33271120080113The Effect of Tooth Surface Conditioning on Microleakage of Compomer Restorations77MostafaMousavinasab. drj@dnt.mui.ac.irBahrnanEshghetorky20101106Introduction Compomers from the standpoint of surface and mechanical properties are categorized between composite resins and glass ionomer cements. Compoglass is atrade name for such compomers The purpose of this study was to evaluate microleakage of compoglass through enamel and dentinal margins following the use of two different surface conditionings. Materials and Methods Forty intact human premolars were chosen and randomly assigned to 4 groups each including 10 teeth. Class v cavities were prepared in the buccal surfaces of the teeth and restored with compo glass as follows: roup I: cavities restored as manufacturer's instruction. Group 2: the cavities restored such as group 1 and then stored in distilled water for one week. Group 3: the cavity surfaces were conditioned by phosphoric acid prior to priming and restoration. Group 4: the cavities restored such as group 3 and then were placed in distilled water for one week. Results The results of this study showed that the minimum degrees of leakage in enamel margins were in group 2 and 4 and in dentinal margins in group 2. The maximum degree in enamel marginswas in group I and in dentinal margins in group 3. Statistical analysis of data showed that there was meaningful difference between groups 2 and 3 in dentinal margins. This difference also was seen between groups I, 3-1, 4 and 2, 4 in enamel margins. Conclusion According to the results ofthis study conditioning and water storage decreased the microleakage in enamel and in dentinal margins, conditioning of the margins increased the microleakage. Key words compomer, conditioning,microleakage