Effect of phytic acid etchant on the structural stability of demineralized dentine and dentine bonding

Objective: This study examined the effect of phytic acid (IP6) in stabilizing the morphology of dentine collagen network and resin-dentine bonding. Methods: Dentine beams were fully demineralized with 10% phosphoric acid (PA) or 1% IP6 (pH 1.2). PA-demineralized beams were divided into three groups: (a) no further treatment (control), (b) treatment with 5% glutaraldehyde (GA) for 1 h and (c) treatment with 1% IP6 (pH 7) for 1 h. IP6-demineralized beams received no further treatment. The beams were then subjected to ultimate tensile strength (UTS) testing. Dentine micromorphology evaluation was performed using a field-emission scanning electron microscope (FE-SEM). Dentine disks were etched with 35% PA for 15 s or 1% IP6 for 30 s. PA-etched dentine disks were divided into three groups as (a), (b) and (c) as for UTS testing, but the treatment with GA or IP6 was done in 1 min. For microtensile bond strength (mu TBS) testing, flat dentine surfaces etched with PA or IP6 were blot-dried (wet dentine) or air-dried for 10 s (dry dentine) and bonded with an etch-and-rinse adhesive followed by composite build-up. Results: IP6-demineralized dentine showed significantly higher UTS, when compared to PA-demineralized dentine. GA and IP6 significantly improved UTS of PA-demineralized dentine. FE-SEM observation revealed that dentine collagen network was preserved by GA and IP6. No significant difference in mu TBS was found between the wet and dry IP6-etched dentine groups. Conclusion: IP6 etching showed a structural stabilizing effect on demineralized dentine matrix and produced good resin-dentine bonding, regardless of dentine moistness or dryness. (C) 2015 Elsevier Ltd. All rights reserved.