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(Reference retrieved automatically from SciELO through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

The influence of chemical activation on hardness of dual-curing resin cements

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Author(s):
Renata Garcia Fonseca [1] ; Carlos Alberto dos Santos Cruz [2] ; Gelson Luis Adabo [3]
Total Authors: 3
Affiliation:
[1] São Paulo State University. School of Dentistry of Araraquara. Department of Dental Materials and Prosthodontics
[2] São Paulo State University. School of Dentistry of Araraquara. Department of Dental Materials and Prosthodontics
[3] São Paulo State University. School of Dentistry of Araraquara. Department of Dental Materials and Prosthodontics
Total Affiliations: 3
Document type: Journal article
Source: Brazilian Oral Research; v. 18, n. 3, p. 228-232, 2004-09-00.
Abstract

During the cementation of metallic restorations, the polymerization of dual-curing resin cements depends exclusively on chemical activation. This study evaluated the influence of chemical activation compared with dual-curing (chemical and light activation), on the hardness of four dual-curing resin cements. In a darkened environment, equal weight proportions of base and catalyst pastes of the cements Scotchbond Resin Cement, Variolink II, Enforce and Panavia F were mixed and inserted into moulds with cavities of 4 mm in diameter and 2 mm in height. Subsequently, the cements were: 1) not exposed to light (chemical activation = self-cured groups) or 2) photoactivated (dual-curing = dual-cured groups). The Vickers hardness number was measured at 1 hour, 24 hours and 7 days after the start time of cements' spatulation. For all the cements, the hardness values of self-cured groups were lower than those of the respective dual-cured groups at 1 hour and 24 hours. At 7 days, this behavior continued for Variolink II and Panavia F, whilst for Scotchbond Resin Cement and Enforce there was no statistical difference between the two activation modes. All cements showed a significant increase in their hardness values from 1 hour to 7 days for both activation modes. Of the self-cured groups, Scotchbond Resin Cement and Variolink II presented the highest and the lowest hardness values, respectively, for all three times tested. Within the limitations of this study, up to the time of 24 h, chemical activation alone was unable to promote similar hardness as to that obtained with dual-curing. (AU)