A comparative research of the effects of laser and conventional etching methods on microleakage in ceramic inlays under in-vitro conditions

A comparative research of the effects of laser and conventional etching methods on microleakage in ceramic inlays under in-vitro conditions. The aim of this study was to comparatively research microleakage of 4 resin cemet following Er:YAG laser and conventional etching. In the study, 105 intact molar teeth extracted in 6 months were used. Teeth were seperated into 15 groups, in which n=7 for microleakage: RelyX U200® (G1), acid + RelyX U200® (G2), laser + RelyX U200® (G3), acid + laser + RelyX U200® (G4), RelyX™ Ultimate (G5), acid + RelyX™ Ultimate (G6), laser + RelyX™ Ultimate (G7), laser + acid + RelyX™ Ultimate (G8), PanaviaF®(G9), acid + PanaviaF®(G10), laser + PanaviaF®(G11), laser + acid + PanaviaF® (G12), acid + VariolinkII®(G13), laser + VariolinkII®(G14), laser + acid + VariolinkII® (G15). The teeth were embedded in acrylic blocks during the apex. İnlay cavities were prepared and polieter impressions ((Impregum, 3M ESPE, ABD) of the preparations were taken for laboratory manufacturing of IPS e.max Press (Programat EP 5000; Ivoclar Vivadent ) inlays. Inlays were cemented with four different resin cements. The teeth were thermocycled (1000X, 5-55°C) and were covered with two layers of nail polish, leaving a 1mm gap around their inlay margines. The teeth were kept in % 0.5 basic fuchsine for 24 hours, washed under tap water and nail varnish was removed by ultrasonic cleaning. The teeth in acryl blocks, were removed buccolingually through 4 parallel parts with 1,5 mm intervals by a diamond bur (Size #909G-035-FG, 3.5 mm Diameter Meisinger USA, LLC) and after each surface erosion were evaluated under a stereomicroscope (Leicamicrosystems® stereo microscope, Ltd.Stereo and microscope systems; Heerburg, Switzerland). Surfaces of the specimens were examined under a stereomicroscope (Leicamicrosystems® stereo microscope, Ltd.Stereo and microscope systems; Heerburg, Switzerland) by enlarging them x10 and x20. Images were evaluated independently by two different dentists. The acquired data was analyzed by SPSS 15.0 (SPSS Inc®. Chicago, IL, ABD) statistics software; for microleakage Kruskal-Wallis and Mann Whitney U test (p<0,05) was used. According to microleakage test findings; PanaviaF® ,acid + PanaviaF®, acid+RelyX™ Ultimate, acid + VariolinkII® groups were found to have less statistically significant scores compared to the other groups (p<0,05). As a result; when microleakage findings were evaluated together, only laser usage wasn't as effective as the acid etching, laser+acid usage was reduced microleakage values relative to the laser usage but it had been found to have a higher microleakage value than acid usage and under the light of these findings it was found that laser usage does not suffice to meet the need of acid etching and conventional etching method still has better results and methods with more stages prolong the duration of the treatment, thus should not be suggested for clinical applications.