JDR Woodhead Publishing
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Full Text (PDF)
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Watson, T. F.
Right arrow Articles by Cook, R. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Watson, T. F.
Right arrow Articles by Cook, R. J.

Journal of Dental Research, Vol 74, 1749-1755, Copyright © 1995 by International & American Associations for Dental Research Online Journals

ARTICLES

The influence of bur blade concentricity on high-speed tooth-cutting interactions: a video-rate confocal microscopic study

T. F. Watson and R. J. Cook
Department of Conservative Dentistry, United Medical School of Guy's Hospital, Guy's Dental School, London, United Kingdom.

This study aimed to determine the degree of eccentricity between different tungsten carbide bur manufacturing techniques and to study the effect of bur inaccuracy on dental enamel. Error in bur concentricity may arise from malalignment of the steel shaft and carbide head in a two-piece construction bur. Cutting blades rotate at multiple radii from the shaft axis, potentially producing vibrations and damage to the cut substrate. Techniques now allow for the manufacture of one-piece tungsten carbide burs with strength adequate to withstand lateral loading. A comparison of tungsten carbide dental cutting tools revealed the true extent of concentricity errors. Variation in alignment of the cutting head and shaft in the two-part constructions incurred between 20 and 50 microns of additional axial error. High-speed cutting interactions with dental enamel between carbide burs were studied by means of a video-rate confocal microscope. A cutting stage fitted to a Tandem Scanning Microscope (TSM) allowed for real-time dynamic image acquisition. Images were captured and retrieved by means of a low-light-level camera recording directly to S-VHS videotape. Videotape showing the interactions of high-speed rotary cutting instruments (at 120,000 rpm) were taken under simulated normal wet-cutting environments, and the consequent damage to the tooth tissue was observed as it occurred. Concentrically engineered bur types produced a superior quality cut surface at the entry, exit, and advancing front aspects of a cavity, as well as less subsurface cracking. Imaging of the coolant water film local to recent cutting operations showed regular spherical cutting debris of 6 to 18 microns diameter from the concentric tools, whereas the less-well-engineered burs produced ragged, irregular chips, with 25-40 microns diameter debris, indicating far more aggressive cutting actions. This study has shown that there is reduced substrate damage with high-concentricity carbide burs.




HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
IADR Journals Advances in Dental Research ®
Journal of Dental Research ® Critical Reviews (1990-2004)
Copyright © 1995 Institutional Access Guidelines