Correlation of Laser Vibrometric and Laser Profilometric Scaler Instrumentation Damage

Objectives: Ultrasonic scalers have the potential to damage tooth surfaces through impaction of the oscillating probe. The aim of this study was to correlate the vibration patterns of a Slimline ultrasonic scaling tip under various load conditions with any damage caused to the tooth surfaces.

Methods: Crowns from extracted molar teeth were removed using a bone saw. The remainder of the tooth was hemisected and set into resin to produce the experimental specimens. The exposed dentine surfaces were polished to provide a uniform surface. Displacement amplitude measurements were made, using a laser vibrometer, of a FSI-SLI-10S scaler tip (Dentsply, USA) contacting against the dentine surface with loads of 100g and 200g. Water flow was set at 20 ml/min. Operating conditions included low, medium and high power settings. The instrument was set in one position thus allowing the oscillating tip only to contact the tooth with an angle of 15 degrees. Following instrumentation, the dentine surfaces were scanned using a laser profilometer to detect any alteration of the tooth surface

Results: Displacement amplitudes for the scaler tip were shown to be reduced with increasing load and increased with increasing power. Contact of the scaler with the surface at 100g load produced indentations in the tooth (depth = 31.3 ± 2µm and width = 340.7 ± 1.8µm). Increasing power did not affect the depth but did result in an increased width of indentation. Increasing both loading and power setting resulted in both an increased width and depth of indentation. (depth = 86.1 ± 12.23µm and width = 507.5 ± 46.83µm).

Conclusion: Both the load applied and power setting influence the amount of indentation damage produce to a tooth surface. Higher loading should be avoided during ultrasonic scaling procedures as it will result in the greatest alteration of the tooth surface.