INFLUENCE OF TWO ETCHING SYSTEMS ON THE MICROLEAKAGE OF COMPOSITE CROWNS OVER POST-CORE RESTORATIONS

Purpose: for the treatment of excessively damaged teeth, post-cores and subsequent porcelain crowns restoration may be very challenging for the clinician due to their higher costs and longer chairside time leading to a search for alternative treatments. composite crown restorations rise up as an alternative technique as the abrasion rates decrease with the new generation highly filled composites. although significant increase in the bond strength values were reported, the occurrence of microleakage and gap formation, mostly at the dentincomposite interface, did not seem to decrease with a similar rate. the purpose of this study was to compare the conventional acid etching and laser etching techniques and to evaluate their effects on the leakage rate of post core restorations. materials and methods: 40 recently extracted human mandibular premolars were used in this study. endodontic accesses were prepared conventionally and the posts were conditioned according to manufacturer’s instructions. for the cementation of fiber posts, a dual polymerized resin luting agent was used. the samples were divided into two groups according to the etching technique: acid-etching with 37% phosphoric acid (using the conventional technique) and er,cr:ysgg hydrokinetic dental laser etching. following the restoration procedure, the teeth were stored in saline at 37°c for one week and then thermocycled 1500 cycles between 5° and 55°c. teeth were left in %0.5 basic fuchsin for 24 hours and microleakage was evaluated using a stereomicroscope at the magnification of 8x. chi-square test was used for statistical analysis. results: the results were evaluated with “chi-square” statistical analysis. no statistically significant difference was observed between the acid etch and laser etch groups (p>0.05), even though the laser etched group showed numerically lesser dye penetration than the acid etched group. conclusions: within the limitations of this study it was shown that acid etching or laser etching had similar microleakage characteristics.