It may be concluded that base metal-ceramic bond strength is affected by aging and the effect is relatively the same for all the tested porcelain-metal systems.
Background
Pressing esthetic demands of good looking make people undergo bleaching procedures. However, the effect of bleaching agents on esthetic restorative materials with different surface preparations has been poorly studied.
Aim
The aim of this study was to examine the effect of a homebleaching agent (carbamide peroxide: CP 38%) on the surface roughness of the polished fiber reinforced composite (FRC), overglazed, autoglazed, or polished ceramic samples.
Materials and methods
Twenty standardized cylindrical specimens were made of each of the following groups: overglazed, autoglazed, polished porcelain and also FRC. The test specimens exposed to the CP 38%, 15 minutes, twice a day for 2 weeks according to the manufacturer's recommendation. Six samples from each group were selected randomly to form negative controls. Surface roughness measurements (Ra, micrometer) for baseline, test and control specimens were performed by use of a profilometer. Paired t-test, Mann-Whitney test, and Kruskal-Wallis test were used for statistical analyses.
Results
The data showed that bleaching with CP 38% significantly increased the surface roughness of all the test samples (p < 0.05). The type of surface preparation caused significant differences between the susceptibility of porcelain subgroups to bleaching (p < 0.05). The polished porcelain specimens showed the highest changes after bleaching.
Conclusion
CP 38% significantly increases the surface roughness of the porcelains and FRC. The type of surface condition affects the amenability of the porcelain surface to the bleaching agent. Glazed porcelains were more resistant to roughness than the polished porcelains and also the composite.
Clinical significance
Roughening of porcelain and FRC occur following bleaching procedure. No special surface preparation of indirect esthetic restorative materials can completely preserve these materials from adverse effects of bleaching agents.
How to cite this article
Torabi K, Rasaeipour S, Khaledi AA, Vojdani M, Ghodsi S. Evaluation of the Effect of a Homebleaching Agent on the Surface Characteristics of Indirect Esthetic Restorative Materials: Part I—Roughness. J Contemp Dent Pract 2014;15(3):326-330.
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