Application Of Erbium Laser On Minimal Intervention: Scanning Electron Microscopy And Microleakage

Objective: The aim of this study was to evaluate the effectiveness of erbium laser on minimal intervention and to analyze microstructural characteristics of COMPOMER-tooth and ESPE glass ionomer-tooth interfaces in older to provide the better instrument and restorative material.Method: Twenty-four human premolars with no carious, which extracted for orthodontic reason, were divided randomly into two groups of twelve each. All the occlusal fissures were opened with OPUS20 erbium-laser(700mj,10pps) and high speed handpiece respectively. Six premolars were randomly picked out from each groups ,half of the specimens picked out from each groups were restored with 3M F2000 Compomer and the rest with ESPE glass ionomer. All of the steps were followed by manufacturer's introductions. After being dried for one day, 12 restored teeth and 3 unfilled teeth chose from each group were sectioned with water spray for cooling. All samples were observed under SEM.In the microleakage study, sixty human no carious molars were assigned randomly into four groups then were prepared according to minimal intervention's instructions. Fissures of group A, B were opened with a high speed handpiece, whereas group C, D with erbium laser. Group A, C and group B, D were restored with Compomer and ESPE glass ionomer respectively. Allteeth were thermocycled, stained with 2% fuchsin solution, sectioned and viewed with stereomicroscope. Measurement will be recorded in absolute millimeters. All the statistical analysis were carried out by T test in SPSS. Results: SEM results showed the surfaces produced by erbium laser were significantly different from conventional control group. The lased surface revealed no charring, carbonization or cracking of enamel or dentin and characteristic micro-irregularities without smear layer.The observation of Compomer-tooth interfaces indicated perfect adaptation both in laser group and handpiece group, but micro-gaps were observed between glass ionomer-interfaces both in laser and handpiece groups. The micro-gaps were smaller in laser group, especially in dentine.Microleakage at the cavity margins was observed in all four groups using the dye penetration method. There was significant difference between group A and B, group C and D(p<0.05) respectively, but no significant differences both between group A and C, group B and D(P>0.05). Microleakage was minimal in group A and C.Conclution: These results suggest that erbium laser is useful for minimal intervention and Compomer provide better option for clinical applications from the viewpoint of SEM and microleakage.