Sharon Crane Siegel

EFFECT OF HANDPIECE LOAD ON THE CUTTING EFFICIENCY OF DENTAL BURS

Abstract A reproducible test regimen was developed to evaluate the cutting efficiency (CE) of diamond dental burs against a machinable glass ceramic, Macor, under three different loads. The test jig used an ultra-highspeed dental handpiece in a frictionless bearing so that the pressure applied to the contact interface between the dental bur and the cutting substrate could be controlled. Loads ranging from 44 to 183 g were used. CE depends on both bur rugosity and the handpiece load. The load used by most dentists, about 100 g at the bur tip, appears to be optimal in that at lower loads CE is reduced, whereas a marked increase in load has no effect for medium-grit burs. With coarse-grit burs, however, increased handpiece pressure raises the CE; it is uncertain what effect this has on the dental pulp. CE also appears to be dependent upon debris accumulation between the diamond particles and wear of diamond.

Irrigating solution and pressure effects on tooth sectioning with surgical burs.

OBJECTIVE The purpose of this study was to determine the influence of the applied load on the handpiece, type of cooling agent, and type of tooth on surgical tooth dissection with a tapered crosscut fissure bur. STUDY DESIGN Cutting studies were performed at handpiece loadings of 295 and 590 g through use of an oral surgery straight handpiece, tapered crosscut fissure burs, and an established cutting regimen. Extracted molars were dissected under irrigation with water, 0.9% saline solution, and lactated Ringers solution at constant flow rates of 15 and 25 mL/min. Cutting efficiencies were analyzed by 1-way analysis of variance and Scheffé tests. RESULTS No difference in cutting efficiency was found at low loads under irrigation with water or saline solution, but under irrigation with lactated Ringers solution, a higher cutting efficiency was found (P < .05). There was no difference in cutting efficiency for lactated Ringers solution and saline solution at high loads, but both cut more efficiently than water (P < .01). CONCLUSIONS Saline solution is a useful coolant/irrigant for the dissection of teeth under most conditions, but lactated Ringers solution might be beneficial with respect to cutting efficiency when lower handpiece loads are required.