Bond strength of composite resin to white mineral trioxide aggregate: Effect of different surface treatments

BACKGROUND: The main aim of restorative dentistry is to restore and preserve dental health with the use of appropriate restorative modalities to protect the pulp and restore its function. This study compared the effect of different surface treatments of mineral trioxide aggregate (MTA) on the bond strength of composite resin to MTA. MATERIALS AND METHODS: Forty cylindrical acrylic blocks with a hole were prepared and filled by ProRoot MTA. The samples were assigned to four groups: Group 1 – no surface treatment; Group 2 – phosphoric acid etching; Group 3 – sandblasting; and Group 4 – hydrofluoric acid (HF) etching, rinsing, and silane application. OptiBond Solo Plus adhesive was utilized in all the groups. Then, composite resin cylinders were bonded to sample surfaces. The samples were thermocycled and tested for microshear bond strength using a universal testing machine at a crosshead speed of 1 mm/min. Data were analyzed with Kruskal–Wallis and Mann–Whitney tests. Scanning electron microscopy images were prepared for each study group after surface treatments. RESULTS: Means and standard deviations of bond strength values in study groups 1–4 were 14.83 ± 7.76, 21.85 ±7.99, 6.48 ± 3.89, and 26.01 ± 11.09 Mpa, respectively. CONCLUSIONS: Within the limitations of this study, phosphoric acid etching or HF etching plus silanization was preferred to surface treatment of MTA before composite resin bonding.