A reinforcement method for retainer polymer using biocompatible glasscloth.

Abstract

Orthodontists sometimes experience cases of breakage of a retainer in the marginal area. The aim of this study was to determine whether the use of glass cloths improves the mechanical properties of polymer for retainers. The glass cloths were silanated before fabrication. All test specimens were 2 x 15 x 40 mm in size. The specimens were divided into three types according to the manner of containment of the glass cloth : without reinforcement (type 1), the cloth in the neutral zone (type 2) and the cloth on the surface (type 3). The results were as follows. 1. The elastic moduli of type 2 and 3 specimens were about 1.3- and 1.4-times larger than that of type 1 specimens, respectively. 2. The flexural strengths of type 2 and 3 specimens were about 1.4- and 1.7-times larger than that of type 1 specimens, respectively. Adequate improvement in transverse strength of the retainer polymer was accomplished simply by placing the glass cloth. This method using biocompatible glass cloth is a simple method for reinforcing resin and is thought to be effective for preventing breakage of retainers.