Methods: Metal discs of 1 cm diameter and 1 mm thickness (n=60) were prepared from Wiron 99 non-precious alloy (BEGO Bremer Goldschägerei with Herbst GmbH& Co. Bremen. Germany). The discs were veneered from one side by 1 mm thickness Vita 3D Master feldspathic porcelain (Vita zhan fabric H. Rauter GmbH & Co. KG. Germany). Orthodontic metal brackets were bonded at the center of each disc (3M, Unitek), and then discs were water stored for 30 days before debonding. Brackets were debonded using bracket removing pliers, and resin was removed with a 12-fluted carbide bur. The prepared specimens were divided into 3 groups (n=20) representing different porcelain refinishing techniques as follows; group 1: using (Shofu, USA) porcelain veneer kit, group 2: using (Ultradent, USA) porcelain finishing kit, and group 3: using (Sof-lex 3M, USA) porcelain polishing kit. Measurements for surface roughness and color were made before bonding (baseline) T1, after debonding T2, and after each refinishing technique T3. The surface roughness (Ra) was evaluated using USB Digital microscope with a built-in camera (Scope Capture Digital Microscope, Guangdong, China). WSxM software was used to calculate root mean square (RMS) of the average height of every specimen, expressed in μm. Data was analyzed with 2-way ANOVA followed by Turkey HSD tests (α = 0.05).
Results: The polishing techniques affected surface roughness significantly (P<0.001), with insignificant higher Ra values than the glazed baseline porcelain. The surface roughness values were not statistically different among the polishing groups (P>0.05).
The results of this study indicate that the tested polishing techniques were able to reestablish the original glazed porcelain smoothness.
Keywords: Ceramics, Orthodontics, Porcelain systems and refinishing
See more of: Dental Materials 3: Ceramic-based Materials and Cements