Influence of operator skill on microleakage of total-etch and self-etch bonding systems

Abstract OBJECTIVES: To evaluate the influence of operator skill on microleakage in class V restorations using simplified bonding systems. METHODS: Two cavities were carried out on the buccal and lingual surfaces of 50 human bicuspid teeth. The teeth were randomly assigned to two groups according to the operator's skill: student group and expert group. The two cavities of each tooth were randomly treated with Adper Scotchbond 1 XT (total-etch adhesive) and Adper Prompt L-Pop (self-etch adhesive). All cavities were restored with a 0.2mm thick layer of flowable composite (Filtek flow) followed by one bulk increment of resin composite (Filtek Supreme XT). Specimens were thermocycled, immersed in 2% methylene blue and sectioned in a bucco-lingual plane. They were then examined under a stereomicroscope and scored according to microleakage. The data was subjected to a multilevel statistical model. RESULTS: At the dentine margin the microleakage resulting from both the self-etch adhesive and the total-etch one was similar in the student and in the expert groups. The interaction term skill x adhesive was not statistically significant (p=0.4156). At the enamel margin the self-etch adhesive microleakage within the student group resulted lower than that within the expert group. On the other hand, the total-etch adhesive microleakage within the expert group resulted lower than that within the student group. The interaction term skill x adhesive was statistically significant (p=0.0037). CONCLUSIONS: Both the adhesives used were sensitive to operator skill in obtaining a reliable seal with the enamel. On the dentine, both adhesives demonstrated little sensitivity to operator skill.