Background: Repair of a failed amalgam or composite resin (CR) restoration has been extremely studied and proposed as a routine clinical treatment option; however, repair potential of glass ionomer-based restorative materials was not studied sufficiently in the literature.
Aim: The aim of this study is to evaluate the repair potential of a glass hybrid (GH) restorative repaired either by the same material (GH) or CR after different surface treatments using microtensile bond strength (μTBS) test.
Methods and materials: One hundred and twenty bar-shaped (2 × 2 × 8 mm) GH blocks were prepared. After aging, the specimens were divided into two groups (n = 60) and five subgroups (n = 12). The specimens in Group I were repaired with the following protocols: (a) no treatment + GH, (b) diamond bur (B) + GH, (c) cavity conditioner + GH, (d) cavity conditioner + universal adhesive (A) + GH, (e) A + GH, and specimens in Group II were repaired with (a) no treatment + CR, (b) B + CR, (c) B + A + CR, (d) 40% phosphoric acid + A + CR, (e) A + CR. The specimens that were subjected to μTBS testing, scanning electron microscopy evaluations, and fracture modes were determined. Data were analyzed using Kruskal-Wallis and Mann-Whitney U tests (P = 0.05).
Results: Repair using CR resulted in higher bond strengths (P < 0.001). The lowest bond strength was obtained in Group Ie. The highest bond strength was obtained when GH was roughened in Group IIc.
Conclusion: Repair of restorative GH with CR appears as a preferred option to improve the bond strength.
Keywords: Composite resin; microtensile bond strength; repair; restorative glass ionomer.