A study on surface roughness and microleakage test in cavities prepared by Er:YAG laser irradiation and etched bur cavities

Abstract

The purposes of this study were to investigate the surface morphology, suface roughness of cavities prepared by Er:YAG laser irradiation, and compared the microleakage degree after composite resin restoration with etched bur cavities, in vitro. In each of the 30 human extracted teeth, two shallow cavities were prepared; one prepared with the Er:YAG laser system on the buccal surface, and one produced on the lingual (palatal) surface with a high-speed turbine. Five cavities from each group were investigated by scanning electron microscopy (SEM), and five were subjected to surface roughness analysis by a colour laser three-dimensional (3D) microscope. The remaining cavities were filled with a composite resin and subjected to a microleakage test under thermocycling. Only bur cavities were acid-etched before filling. Statistical analysis was performed using the Mann-Whitney U test; a value of p <0.01 was considered significant. Morphologically, the prepared cavities showed an irregular surface with the absence of a debris-like smear layer; enamel prisms and opening of dentinal tubules were recognised. Surface roughness was significantly increased with the laser system. Microleakage test revealed no significant differences between the laser and bur cavities. Crosscut sections of the cavities with no microleakage showed no gap at the interface. Laser cavity may facilitate good adaptation of composite resin with enamel and dentine, because an increase of surface roughness and the openings of dentinal tubules may facilitate the formation of a hybrid zone, since a primer and an adhesive can penetrate the surface better when the smear layer is removed. It can be concluded that shallow cavity prepared by Er:YAG laser is capable of decreasing microleakage of composite resin restorations, and its efficiency is similar to etched bur cavities.

Assessment of Microleakage of a Composite Resin Restoration in Primary Teeth Following Class III Cavity Preparation Using Er, Cr: YSGG laser: An In Vitro Study

“…26 In cavities that were conventionally prepared, etching with phosphoric acid resulted in removal of smear layer and exposure of enamel prism sheaths and dentinal tubules. 27 In this study, microleakage was seen to be higher following conventional etching. This is probably because there are no definite etching patterns seen in primary teeth.…”

“…7 The highly irregular surfaces following laser treatment results in loss of smear layer, intact enamel rods and opening of dentinal tubules. 15,27 In the absence of a smear layer, there can be improved adhesion due to better penetration of both primer and adhesive. 3,13,27 Howev- er, Bertrand et al reported of better marginal adaptation of restorations in permanent teeth, when Er:YAG laser preparation was followed by total acid etching.…”

Effects of different types of adhesive systems on the microleakage of compomer restorations in Class V cavities prepared by Er,Cr:YSGG laser in primary teeth

“…Many studies have examined the effects of erbium laser and diamond bur preparation on microleakage 14,15,29,[52][53][54][55] . Some studies found that laser irradiation exhibited same or even better microleakage outcome than did the conventional bur method [53][54][55] , but other studies had contradictory results 29,52) . During cavity preparation with burs, the inevitable noise, vibration, pressure, and heat caused by high-speed drilling inevitably brings much discomfort and displeasure to the patient 56,57) .…”

Clinical Comparison of Bur- and Laser-prepared Minimally Invasive Occlusal Resin Composite Restorations: Two-year Follow-up

“…31 In another study, cavities prepared by Er:YAG laser were found to be capable of decreasing the microleakage of resin composite restorations, and their efficiency was similar to etched bur cavities. 32 Moldes and others 33 compared the degree of microleakage of composite restorations performed by lasers and those by conventional drills associated with two adhesive systems. The enamel margins demonstrated no differences in microleakage for all treatments.…”