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

• Published in: Journal of the mechanical behavior of biomedical materials 2015-08, Vol.48, p.145-152
• Main Authors: Kong, Kalyan, Islam, Md. Sofiqul, Nassar, Mohannad, Hiraishi, Noriko, Otsuki, Masayuki, Yiu, Cynthia K.Y., Tagami, Junji
• Format: Article
• Language: English
• Subjects: Cross-linker; Dental Bonding; Dental Stress Analysis; Dentin - drug effects; Dentin - physiology; Glutaraldehyde; Humans; Microtensile bond strength; Phosphoric acid; Phytic acid; Phytic Acid - pharmacology; Resin Cements; Surface Properties; Tensile Strength; Tooth - drug effects; Tooth - physiology; Ultimate tensile strength
• ISSN: 1751-6161; 1878-0180
• DOI: 10.1016/j.jmbbm.2015.03.027

This study examined the effect of phytic acid (IP6) in stabilizing the morphology of dentine collagen network and resin–dentine bonding. 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 1h and (c) treatment with 1% IP6 (pH 7) for 1h. 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 15s or 1% IP6 for 30s. 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 1min. For microtensile bond strength (µTBS) testing, flat dentine surfaces etched with PA or IP6 were blot-dried (wet dentine) or air-dried for 10s (dry dentine) and bonded with an etch-and-rinse adhesive followed by composite build-up. 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 µTBS was found between the wet and dry IP6-etched dentine groups. IP6 etching showed a structural stabilizing effect on demineralized dentine matrix and produced good resin–dentine bonding, regardless of dentine moistness or dryness. [Display omitted] •IP6 has the potential to etch dentine and stabilize collagen network simultaneously.•Bonding to IP6-etched dentine is less affected by dehydration of dentine surface.•Technique-sensitivity of etch-and-rinse adhesive might be reduced if IP6 is used.