Year : 2020

Volume : Volume 11

Issue : Issue 2

Address for correspondence :
Dr. Rashmi Issar.
RashmiIssar@gmail.com

Abstract

Background: The ultimate goal for adhesive dentistry has been to create a perfect bond between the dental composite and the tooth substrate. The micromechanical roughness of the substrate has been a key factor to achieve this goal. The evolution in terms of agents used to produce predictable in vivo bond strength has taken a massive leap after introduction of hard tissue laser. The present study explores the usage of both Er,Cr:YSGG and acid etching at different time intervals on prepared enamel specimens and measures in vitro shear bond strength values.  Materials & Methods: On prepared enamel samples the laser treatment was done followed by acid etching at different intervals. Groups E20, E40 and E60 were divided and acid etched for 20sec, 40 sec and 60 sec each followed by placement of bonding agent and dental composite. The samples later subjected to shear bond strength analysis using Instron equipment. The specimens were also analysed by SEM to assess the failure mode.  Results: The maximum shear bond strength of 21.33±4.3 Mpa for enamel specimens was achieved when the etching time was increased to 40 sec. On subjecting the groups to ANOVA statistical analysis, the difference between group E40 as compared to E20 and E60 was statistically significant (p<0.05). On SEM evaluation of the specimens for the mode of failure cohesive failure predominated in all the groups. Conclusion: Within the limitations of the present study, it can be concluded that the use of hard tissue laser on enamel surfaces along with 37% phosphoric acid application for 40 sec helps in achieving a predictable and reliable bond strength in vitro. The predominance of cohesive bond failure on SEM evaluation of the samples is suggestive of the adhesive surfaces resisting the fracture.

Keywords: Acid etching, Adhesive bonding, Er,Cr:YSGG, Shear bond strength.