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Volume 7, Issue 2 (Suppl)

J Biotechnol Biomater

ISSN: 2155-952X JBTBM, an open access journal

Biomaterials 2017

March 27-28, 2017

Annual Conference and Expo on

March 27-28, 2017 Madrid, Spain

T Eliades, J Biotechnol Biomater 2017, 7:2 (Suppl)

Viscoelasticity of dental polymers used for orthodontic applications

T Eliades

University of Zurich, Switzerland

Aim:

To evaluate the viscoelastic properties of two experimental BPA-free and one BisGMA-based orthodontic resin composite

adhesives for bonding fixed retainers.

Materials & Methods:

A commercially available BisGMA-based (TXA: Transbond LR) and two Bisphenol A-free experimental

adhesives (EXA and EXB) were included in the study. The viscoelastic behaviour of the adhesives were evaluated under static and

dynamic conditions at dry and wet states and at various temperatures (21, 37, 50

C). The parameters determined were shear modulus

(G), Young's modulus (E) under static testing and storage modulus (G1), loss tangent (tan δ) and dynamic viscosity (n*) under

dynamic testing. Statistical analysis was performed by 2-way ANOVA and Bonferroni post-hoc tests (α=0.05).

Results:

For static testing, a significant difference was found within material and storage condition variables and a significant

interaction between the two independent variables (p<0.001 for G and E). EXA demonstrated the highest G and E values at 21

C/dry

group. Dry specimens showed the highest G and E values, but with no significant difference from 21

C/wet specimens, except EXA in

G. Wet storage at higher temperatures (37

C and 50

C) adversely affected all the materials to a degree ranging from 40-60% (p<0.001).

For dynamic testing, a significant difference was also found in material and testing condition groups, with a significant interaction

between the two independent variables (p<0.001 for G1 and n*, p<0.01 for tan δ). Reduction in G1, and n* values, and increase in tan

δ values were encountered at increased water temperatures.

Biography

T Eliades is a Professor and Director of the Clinic of Orthodontic and Paediatric Dentistry, University of Zurich, Switzerland.