Influence of two methods of additional activation on composite resins surface hardness|
Gonçalves, Alessandro Ribeiro; Rodrigues, Caroline de Deus Tupinambá; e Souza, Carlos Henrique de Carvalho; de Sousa, Leilane Ferraz Moreira & Lopes, Pedro Henrique de Souza
Aim: To evaluate the influence of two methods of additional activation on the surface hardness of
composite resins. Methods: Two types of composites were tested: Filtek P60 and Filtek P350.
For each material, 48 specimens were prepared and divided into four groups: Group 1 (control)
- conventional activation, using a halogen light for 40 s; Group 2 - conventional activation and
additional activation with a halogen lamp for 60 s; Group 3 - conventional activation and additional
activation with an autoclave at 127°C for 6 min at 1.7 kg/cm3 pressure; and Group 4 - conventional
activation and additional activation with an autoclave at 134 °C for 15 min at 2.1 kg /cm3 pressure.
The use of autoclave has been suggested for being a standard equipment at dental offices, and
thus, even at locations far from dental laboratories, it would be possible to have simple techniques
that allow access to indirect restorations at lower costs. Data obtained in the study were analyzed
statistically by analysis of variance followed by Tukey’s test at a 5% level of significance. Results:
For Z350, there was a significant increase in hardness for all groups of additional activation
(Groups 2, 3 and 4), compared with the control group. For P60, a significant increase in surface
hardness was found compared with the control group for the groups that used additional activation
with an autoclave (Groups 3 and 4). Conclusions: Additional activation with an autoclave
increased the surface hardness of the tested resins to a greater degree than additional activation
with a halogen light.
polymerization, composite resins, hardness.