Effect Of Different Surface Pretreatment Protocols On The Micro-Shear Bond Strength Of Resin Composite To Resin Infiltrated Demineralized Enamel

Abstract

Aim: to assess micro-shear bond strength (µ-SBS) of composite using universal adhesive to resin infiltrated demineralized enamel after different surface pretreatments. Methodolgy: Thirty-six intact maxillary central incisors were used. Teeth were mounted in acrylic blocks. Specimens were divided into three groups ;Group 1: teeth with sound enamel were bonded to resin composite (positive control). Group 2: teeth were demineralized then bonded to resin composite (negative control). Group 3: teeth were demineralized followed by application of (Icon-DMG). The third group was divided into four subgroups according to surface pretreatment either no surface pretreatment, abrasive roughening, air abrasion, combination of roughening and air abrasion. All specimens except positive control were demineralized by demineralizing solution. In resin infiltration group, Icon (DMG) was applied following manufacturer’s instructions then specimen’s surfaces were treated as mentioned before. Etch and rinse approach using universal adhesive was applied before composite packing. Five 2millimeters long micro-tubes were mounted and held in place on the uncured adhesive. The adhesive coat was then light cured and composite was packed in the microtubes. Microtubes were peeled obtaining five microcylinders for µ-SBS testing. µ-SBS testing was done using a universal testing machine with orthodontic wire to produce shear forces. Results: statistically significant difference in µSBS values between different study groups was found. The highest µSBS mean values were in positive control, grinding and air abrasion groups, followed by no treatment group, combination group. While negative control yielded lowest µSBS values. Conclusion: surface pretreatment is mandatory to improve bonding to resin infiltrated enamel.