Comparison of cutting rates among single-patient-use and multiple-patient-use diamond burs.

Purpose: The purpose of this study was to compare the volumetric cutting rates of 6 cylindrical-shaped single-patient-use and 2 cylindrical-shaped multiple-patient-use diamond burs using a machinable ceramic material. The degree of wear among burs from each type was also compared using scanning electron microscopy.

Materials And Methods: Six types of single-patient-use diamond burs and 2 types of multiple-patient-use diamond burs with similar cylindrical shape and dimensions were selected. Five burs of each type were evaluated using a high-speed handpiece mounted on a custom testing device. Using a 6-mm cutting length of each bur, 20 cuts, each 12.2-mm long, were made at exactly one half the diameter of the bur. Mean volumetric cutting rate through the ceramic substrate for Cuts 1 through 20 was calculated for each bur type in cubic millimeters prepared per second. A repeated measures analysis of variance (alpha = 0.05) and post hoc one-way analysis of variance with Scheffé's test was used to compare cutting rates among bur types for Cuts 2, 10, and 20. The topography of one bur from each group was evaluated with scanning electron microscopy after Cut 2 and again after Cut 20.

Results: For Cut 2, the mean cutting rates ranged from 3.3 to 5.3 mm3/s. The mean cutting rates for all bur types decreased approximately 20% by Cut 20. Bur type and length of use significantly influenced cutting rate (p < .002). However, only one type of single-patient-use diamond bur had a significantly lower mean cutting rate after Cut 2, 10, and 20, compared with other single- and multiple-patient-use diamond burs. Scanning electron microscopy showed all burs exhibited wear of diamond particles, as well as loss of diamond particles and binder.

Conclusions: Five of six single-patient-use diamond burs had mean volumetric cutting rates through a ceramic that were similar to 2 multiple-patient-use diamonds for as many as 20 cuts. The gradual reduction in cutting rate during the 20 cuts for all bur types was a result of bur wear.