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VOLUME 14 , ISSUE 5 ( September-October, 2013 ) > List of Articles


Long-Term Surface Hardness and Monomer Conversion of a Nanofilled and a Microhybrid Composite Resin

Mateus Rodrigues Tonetto, Matheus Coelho Bandéca, José Roberto Cury Saad, Edson Alves de Campos, Fernanda Ferreira Jassé, Carlos Henrique Braga Borges, Alessandra Nara de Souza Rastelli, Vanderlei Salvador Bagnato, Reidson Stanley Soares dos Santos

Citation Information : Tonetto MR, Bandéca MC, Saad JR, de Campos EA, Jassé FF, Borges CH, de Souza Rastelli AN, Bagnato VS, Santos RS. Long-Term Surface Hardness and Monomer Conversion of a Nanofilled and a Microhybrid Composite Resin. J Contemp Dent Pract 2013; 14 (5):876-882.

DOI: 10.5005/jp-journals-10024-1419

Published Online: 01-10-2013

Copyright Statement:  Copyright © 2013; Jaypee Brothers Medical Publishers (P) Ltd.



This study aims to evaluate the degree of conversion (DC) and hydrolytic degradation through the Vickers hardness test (HV) of a nanofilled (FiltekTM Z-250, 3M) and a microhybrid (FiltekTMSupreme-XT, 3M) composite resin.

Materials and methods

Eight disk-shaped specimens (4 mm diameter × 2 mm thick, ISO 4049) of each material were prepared for each test. Composites were inserted into single increment in a metallic matrix and light-cured for 40 seconds. VH readings were performed for each specimen at predetermined intervals: immediately after polymerization (control), 1, 2, 3, 7, 14, 21, 30 and 180 days. After curing, initial hardness measurements were performed and the specimens were immersed in artificial saliva at 37°C. For DC (%), specimens were ground, pressed with KBr and analyzed by FT-IR spectrophotometer.


Student t-test showed that there was no difference between the resins for DC (p = 0.252). ANOVA analysis revealed that Z-250 VH means were all greater than S-XT, for both top and bottom surfaces, whatever the storage-period in artificial saliva (p < 0.001). After 180 days of storage, the hardness obtained for S-XT was similar with that at the baseline, for both top and bottom surfaces. While for Z-250 hardness was not significantly different from baseline only for top surface, but there was a significant decrease observed in hardness for bottom surface.


The materials tested showed no evidence of hydrolytic degradation in a significant way, in a 6-month storagetime in artificial saliva. Nanofilled resin presents a monomer conversion comparable to the conventional microhybrid.

How to cite this article

Jassé FF, Borges CHB, Tonetto MR, de Souza Rastelli AN, Bagnato VS, de Campos EA, Bandeca MC, Saad JRC. Long-Term Surface Hardness and Monomer Conversion of a Nanofilled and a Microhybrid Composite Resin. J Contemp Dent Pract 2013;14(5):876-882.

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