The effect of bioglass air-abrasion and bonding-agent on fissure-sealant microleakage

Introduction: Enamel surface is normally etched by an acid prior to fissure-sealing teeth. However, aprismatic enamel in deep pits and fissures is resistant to acid-etching and so removal by mechanical means has been suggested. Air-abrasion, a means of enamel pretreatment, is a pseudo-mechanical non-rotary method of removing tooth tissue using the kinetic energy of a stream of desiccated abrasive particles to bombard tooth surface at high velocity. Bioglass is a silicate-based glass with calcium and phosphate similar to hydroxyapatite which could be used as the abrasive agent in this technique. Objectives: To investigate the effect of bioglass air-abrasion and an etch-and-rinse two-step bonding agent on microleakage of fissure sealants. Methods: Ten sound extracted human premolar teeth were used in the pilot study and 50 teeth were used in the main study. Half of the occlusal surface was subjected to five seconds of bioglass air-abrasion and the occlusal surface was then etched. Twenty five teeth received bonding agent (OptiBond®Solo Plus ™) and later all teeth were fissure sealed, covered with varnish and immersed in 0.25% rhodamine. All teeth were cut into 3 sections in a bucco-lingual direction in order to be evaluated for rhodamine leakage using a confocal microscope. Results: Linear mixed models showed that abrasion reduces microleakage in both bonding (P<0.001) and non-bonding (P<0.013) groups. This was confirmed with a Chi-square test [bonding (P<0.023); non-bonding (P<0.042)] on dichotmised data. Air-abrasion had a greater effect in terms of microleakage reduction than that of the bond (P<0.003). When microleakage was analysed as a binary response, results showed that it was the combined effect of the bioglass air-abrasion and the presence of the bond that was the most significant (P<0.006). Conclusions: Bioglass air-abrasion and bonding agent both reduced microleakage. However, the effect of bonding agent was not as beneficial as air-abrasion.