Factors affecting microleakage of a packable resin composite: an in vitro study

This study was designed to determine the effects of three factors on the microleakage of a packable resin composite: different adhesive systems (single-step self-etching adhesive or total-etch and one-bottle adhesive), the use of a flowable resin composite (as a liner) and the different techniques of cavity preparation. Sixty extracted non-carious human first and second molars were selected and randomly divided into six groups. Cervical cavities were prepared using the conventional technique on the distal sides and the air-abrasive technique was used on the mesial sides of the teeth. The experimental groups were restored with PQ1 + SureFil or Prompt L-Pop + SureFil with or without PermaFlo. In the control groups, only SureFil was used on 10 teeth and PermaFlo + SureFil was applied on the remaining 10 teeth. The restored teeth were stored in 100% humidity at 37 degrees C for 24 hours and thermocycled between 5 degrees C and 55 degrees C for 100 cycles. Each tooth was immersed in India ink for 48 hours, then sectioned. Dye penetration at the occlusal and gingival margins was scored by two independent operators. The data were statistically analyzed to assess the differences between the test and control groups. No significant differences among the adhesives in terms of the occlusal margins of the cavities were observed. However, PQ1 led to less microleakage compared to Prompt L-Pop at the gingival margins (p < 0.0062). When flowable resin composite was used with Prompt L-Pop, microleakage was reduced (p < 0.0125). However, no significant difference was observed between the two cavity preparation techniques (p > 0.0125).