Comparison of Ultrasonic Scaling Wear and Roughness Produced InVitro

Objective: To compare the wear (material removal) and roughness produced by three ultrasonic scaler tips on extracted teeth root surfaces and on an industry standard artificial smooth surface.

Methods: The roughness produced by three scaling tips used by an experienced practitioner with standard motion and pressure for 45 seconds, was evaluated using a 1-5 scale (5-highest roughness). All evaluations were done by two calibrated evaluators who were blind as to group assignment. The extracted teeth roots were sterilized, cut into blocks of 12 mm in length, examined to insure an unaltered surface and randomly assigned to a scaling group. Industry standard smooth acetal blocks (DelrinŠ, DuPont) were equally treated. Treated surfaces were coded and then evaluated. The three ultrasonic tips compared were a standard (ST) (EMS PS), a fine abrasive diamond-coated tip (DT) (EMS DPL3), and a smooth tip with external depressions filled with an abrasive diamond-coat (DS) (Vista Dental HST). Acetal block wear was measured by comparing before to after block thickness at the center of the treated area.

Results: A total of 21 tooth blocks and 21 acetal blocks were evaluated. The ST and DS removed similar amounts of material from the acetal blocks (0.064mm, 0.056mm) and root blocks (0.161mm, 0.111mm). The DT removed significantly more material from the acetal (0.177mm) and the root blocks (0.43mm) (ANOVA with Sidak's Post Hoc comparison p< .0001). The DT also produced significantly more roughness than the ST or DS (Mann-Whitney p< .0001).

Conclusion: The ST and DS appear to be similar in wear (material removal) and post-scaling roughness, while the DT significantly removed more material and caused more roughness. The ST and DS appear equally safe for scaling and root planing while the DT appears to cause significant and potentially deleterious changes to the surfaces tested.