Nanofiller loading level: Influence on selected properties of an adhesive resin

Conde, M.C.M.; Zanchi, C.H.; Rodrigues-Junior, S.A.; Carreño, N.L.V.; Ogliari, F.A.; Piva, E.

doi:10.1016/j.jdent.2009.01.001

« Previous Next »Journal of Dentistry
Volume 37, Issue 5 , Pages 331-335, May 2009

Nanofiller loading level: Influence on selected properties of an adhesive resin

M.C.M. Conde
- Biomaterials Development and Control Center, School of Dentistry, Federal University of Pelotas, RS, Brazil
C.H. Zanchi
- Biomaterials Development and Control Center, School of Dentistry, Federal University of Pelotas, RS, Brazil
S.A. Rodrigues-Junior
- Department of Operative Dentistry, School of Dentistry, Federal University of Pelotas, RS, Brazil
N.L.V. Carreño
- Biomaterials Development and Control Center, School of Dentistry, Federal University of Pelotas, RS, Brazil
- Department of Analytical and Inorganic Chemistry, Institute of Chemistry and Geosciences, Federal University of Pelotas, RS, Brazil
F.A. Ogliari
- Biomaterials Development and Control Center, School of Dentistry, Federal University of Pelotas, RS, Brazil
E. Piva
- Biomaterials Development and Control Center, School of Dentistry, Federal University of Pelotas, RS, Brazil
- Corresponding author at: Biomaterials Development and Control Center, School of Dentistry, Federal University of Pelotas, Rua Gonçalves Chaves, 457, CEP: 96015-560 Pelotas, RS, Brazil. Tel.: +55 53 3222 6690; fax: +55 53 3222 6690.

Received 11 May 2008; received in revised form 9 December 2008; accepted 6 January 2009.

Abstract

Objectives

To evaluate the effect of the filler content in the cohesive strength (σ), Weibull modulus (m) and degree of conversion (DC) of an experimental adhesive system.

Methods

A HEMA/Bis-GMA/TEGDMA-based adhesive was formulated and filled with silica nanofillers in the following weight percentages (wt%): R0=0%; R1=1%; R3=3%; R5=5% and R10=10%. The adhesive of Adper Scotchbond Multi-Purpose (SBMP) system was used as a commercial reference. Twenty dumbbell-shaped specimens with cross-sectional area of 0.5mm² were made per group and tensile tested with a crosshead speed of 0.5mm/min until fracture. The cohesive strength was calculated in MPa. DC was obtained through FTIR after light curing for 25s. Data were submitted to one-way ANOVA and Tukey's test (α=0.05) and to Weibull analysis.

Results

Mean σ results were: R0=65.4±8.4; R1=73.2±8.8; R3=72.0±8.4; R5=73.1±9.7; R10=85.5±13.1 and SBMP=79.0±11.0MPa. R10 presented the highest σ, while R0 showed the lowest. R5 and SBMP did not differ significantly (p<0.05). Weibull analysis revealed no significant difference in structural reliability between groups. The experimental adhesives presented similar results of DC, which, in turn, were significantly higher than the SBMP.

Conclusions

The addition of 10% filler in weight improves the cohesive strength of the adhesive, not interfering in the structural reliability or the degree of conversion.

Keywords: Dentin adhesive, Nanofiller, Cohesive strength, Weibull analysis, Degree of conversion