Journal article

Publication year: 2016

Pages: 21-28

Journal: Journal of Dentistry

Volume number: 51

ISSN: 0300-5712

eISSN: 1879-176X

DOI Link: https://doi.org/10.1016/j.jdent.2016.05.007

Publisher: Elsevier

Abstract: 

Objectives: To investigate the influence of bonding resin thixotropy and viscosity on dentine tubule penetration, blister formation and consequently on dentine bond strength as a function of air-blowing pressure (air-bp) intensity.

Methods: Two HEMA-free, acetone-based, one-bottle self-etch adhesives with similar composition except disparate silica filler contents and different bonding resin viscosities were investigated. The high-fillercontaining adhesive (G-Bond) featured a lower viscous bonding resin with inherent thixotropic resin (TR) properties compared to the low-filler-containing adhesive (iBond) exhibiting a higher viscous bonding resin with non-thixotropic resin (NTR) properties. Shear bond strength tests for each adhesive with low (1.5 bar; 0.15 MPa; n = 16) and high (3.0 bar; 0.30 MPa; n = 16) air-bp application were performed after specimen storage in distilled water (24 h; 37.0 +/- 1.0 degrees C). Results were analysed using a Student's t-test to identify statistically significant differences (p < 0.05). Fracture surfaces of TR adhesive specimens were morphologically characterised by SEM.

Results: Statistically significant bond strength differences were obtained for the thixotropic resin adhesive (high-pressure: 24.6 MPa, low-pressure: 9.6 MPa). While high air-bp specimens provided SEM images revealing resin-plugged dentine tubules, resin tags and only marginally blister structures, low airbp left copious droplets and open dentine tubules. In contrast, the non-thixotropic resin adhesive showed no significant bond strength differences (high-pressure: 9.3 MPa, low-pressure: 7.6 MPa).

Conclusions: A pressure-dependent distinct influence of bonding resin thixotropy and viscosity on dentine bond strength has been demonstrated. Stronger adhesion with high air-bp application is explained by improved resin fluidity and facilitated resin penetration into dentine tubules.

Clinical significance: Filler particles used in adhesive systems may induce thixotropic effects in bonding resin layers, accounting for improved free-flowing resin properties. In combination with high air-bp this effect allows an easy plugging of dentine tubules and elimination of blister structures, both resulting in superior dentine bond strength. (C) 2016 Elsevier Ltd. All rights reserved.

Harvard Citation style: Niem, T., Schmidt, A. and Woestmann, B. (2016) Bonding resin thixotropy and viscosity influence on dentine bond strength, Journal of Dentistry, 51, pp. 21-28. https://doi.org/10.1016/j.jdent.2016.05.007

APA Citation style: Niem, T., Schmidt, A., & Woestmann, B. (2016). Bonding resin thixotropy and viscosity influence on dentine bond strength. Journal of Dentistry. 51, 21-28. https://doi.org/10.1016/j.jdent.2016.05.007