title: Basic study on vibrations during tooth preparations caused by high-speed drilling and Er:YAG laser irradiation.
abstract: OBJECTIVE
  An Er:YAG laser effectively removes dental hard substance, and causes less pain during tooth preparations than high-speed drilling. This laser was introduced to eliminate the noise, vibration, pressure, and heat associated with the high-speed drilling. However, the difference in tooth vibration caused by the Er:YAG laser and the high-speed drill is unclear. Therefore, the aim of this study was to evaluate tooth vibration obtained with the Er:YAG laser and high-speed drill.
  
  
  METHODS
  Each of the five extracted permanent upper first premolars were built up in a plaster box. In this study, a silicone impression material was selected to simulate periodontal tissue. The vibration speed was measured by using a laser Doppler vibrometer.
  
  
  RESULTS
  The Er:YAG laser irradiation energy was 50, 100, 145, 199, 300, and 350 mJ. As irradiation energy increased, vibration of the tooth also rose; a high-correlation coefficient was observed between them. We found that only a small amount of the tooth vibration occurred with the Er:YAG laser preparations. The mean vibration speed and standard deviation with the laser were 166 +/- 28 microm/second when the output energy was 145 mJ, whereas those with the high-speed drill were 65 +/- 48 mm/second. The frequency characteristic approached 230 Hz and 5 kHz, respectively.
  
  
  CONCLUSIONS
  These results show that the high-speed drilling causes greater tooth vibration and has a frequency spectrum near the high sensitivity of hearing compared to the Er:YAG laser. This suggests a potential factor in provoking pain and displeasure during tooth preparation. Future study to examine the relationship of pain and amount of tooth vibration will be planned.
authors.affiliation: Department of Pediatric Dentistry, Meikai University School of Dentistry, 1-1 Keyakidai, Sakado, Saitama 350-0283, Japan. Takamori@dent.meikai.ac.jp
authors.forename: Kazunori
authors.initials: K
authors.lastname: Takamori
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Furukawa
authors.forename: Yoshikatsu
authors.initials: Y
authors.lastname: Morikawa
authors.forename: Tadashi
authors.initials: T
authors.lastname: Katayama
authors.forename: Shigeru
authors.initials: S
authors.lastname: Watanabe
mesh_terms: D003762:Dental Instruments; D006801:Humans; D007834:Lasers; D028022:Low-Level Light Therapy; D008954:Models, Biological; D010146:Pain / Q000209:etiology*; D013314:Stress, Mechanical; D013997:Time Factors; D019246:Tooth Preparation / Q000009:adverse effects*; D014732:Vibration