Flexural Strength of Orthodontic Cement containing Microcapsules

Abstract

Caries on the mineralized tooth structure and interface of dental materials continues to be a significant problem in oral health care. The objective of this study was to demonstrate the effect of microcapsules on the flexural strength of orthodontic resin cement formulations. Microcapsules demonstrate a slow, controlled release of fluoride, calcium, and phosphate ions. Orthodontic resin cements that contained microcapsules were incorporated into formulations at 5 w/w% [2 w/w% 0.8 M NaF, 2 w/w% 5.0 M Ca(NO3)2, and 1 w/w% 3.0 M K2HPO4] with one series exception of 6-10 w/w% microcapsules. In this study TEGDMA was the diluent monomer while Bis-GMA was the toughening monomer. The ratio of “toughening monomer:diluent monomer” was explored over a range of 1:1 to 4:1. Barium boroaluminosilicate glass was loaded over a range of 45-75 w/w%, fumed silica was loaded over a range of 0-5 w/w%. The potential number of formulations analyzing these variables is substantial. Therefore, a range of formulations was executed to further investigate the individual variables. These four variables were continuously altered in order to gain better understanding of the role these ingredients had in the presence of microcapsules on flexural strength. The flexural strength was examined as a function of each individual variable. Further analysis examined whether specific variable combinations lead to ideal flexural strength.