A Novel Apparatus to Standardize the Polishing Protocol to Achieve Different Roughness of Titanium and Zirconia Disc Surfaces.

Purpose: To propose and evaluate standardized polishing protocols for in vitro experiments using a custommade apparatus under controlled force to create consistent surface roughness on titanium and zirconia discs.

Materials and methods: A total of 160 discs were manufactured with a diameter of 10 mm, 80 titanium (Ti) and 80 zirconium oxide (Zr). Specimens were categorized into two groups: controlled force (CF) and without controlled force (WCF). Specimens in the CF group were polished with a custom apparatus incorporating a tension gauge on the Ti and Zr disc surfaces to achieve consistent roughness. The WCF group was polished without the use of a tension gauge. Each group had four subgroups (n = 10): control/machined with no polishing (C), rough (R), smooth (S), and very smooth (VS). The subgroups were processed using a sequence of diamond-impregnated polishing burs and polishing paste.

Results: The CF group showed consistent surface roughness and a gradual decrease in surface roughness. Control in Ti (Ra = 6.5 ± 0.03 μm) and in Zr (Ra = 5.4 ± 0.04 μm); R in Ti (Ra = 3.5 ± 0.06 μm) and in Zr (Ra = 3.2 ± 0.07 μm); S in Ti (Ra = 1.5 ± 0.04 μm) and in Zr (Ra = 1.1 ± 0.06 μm); and VS in Ti (Ra = 0.05 ± 0.002 μm) and in Zr (Ra = 0.02 ± 0.005 μm). There were significant differences for R, S, and SV under CF and WCF in Ti and Zr surfaces.

Conclusions: The specimens polished under control force produced significantly more uniform surface roughness than those polished without controlled force and were produced with a higher degree of consistency.