Shrinkage, stress, and modulus of dimethacrylate, ormocer, and silorane composites
Atais Bacchi1, Victor Pinheiro Feitosa2, Andrea Soares Quirino da Silva Fonseca3, Larissa Maria Assad Cavalcante4, Nikolaos Silikas5, Luis Felipe Jochins Schneider3
1 Department of Prosthetic Dentistry, School of Dentistry, Meridional Faculty - IMED, Passo Fundo, RS, Brazil
2 Department of Restorative Dentistry, School of Dentistry, Federal University of Ceará, Fortaleza, Ceará, Brazil
3 Department of Clinic, School of Dentistry, Veiga de Almeida University - UVA, Rio de Janeiro, Brazil
4 Department of Restorative Dentistry, School of Dentistry, Fluminense Federal University, Rio de Janeiro, Brazil
5 Biomaterials Science Research Group, School of Dentistry, University of Manchester, Manchester, United Kingdom
Dr. Atais Bacchi
Rua Evaristo Tagliari, 430/102, Passo Fundo, RS, 99010-470
Source of Support: None, Conflict of Interest: None
Purpose: to evaluate the shrinkage, polymerization stress, elastic and bulk modulus resulting from composites formulated by siloranes, 2 nd generation ormocers, and dimethacrylates.
Materials and Methods: The bonded disc method was used to evaluate volumetric shrinkage. The polymerization stress was evaluated by mean of the Bioman. Cylindrical specimens (5 mm thickness and 6 mm diameter) were submitted to gradual loading. Young's and bulk modulus were obtained from the slope of the stress/strain curve. Data were analyzed using one-way analysis of variance and Tukey's test (5%).
Results: Grandio and ormocer showed significant higher elastic and bulk modulus. Silorane presented significant lowest bulk modulus and maximum shrinkage. Ormocer and silorane presented lower values for the maximum rate of shrinkage. Extra-low shrinkage (ELS) composite presented the greatest maximum shrinkage. The higher maximum rate of shrinkage was attained by Grandio and ELS, statistically similar from each other. The silorane showed lower values of maximum stress and maximum rate of stress. The higher values of maximum stress were presented by ELS and Grandio, statistical similar between them. Grandio showed the significantly greatest maximum rate of stress.
Conclusion: Silorane showed to promote lower shrinkage/stress among the composites, with the lowest elastic modulus. Ormocer showed lower shrinkage/stress than methacrylates despite of its high modulus.