title: Intraosseous heat generation during sonic, ultrasonic and conventional osteotomy.
abstract: OBJECTIVE
  To assess heat generation in osteotomies during application of sonic and ultrasonic saws compared to conventional bur.
  
  
  METHODS
  Two glass-fiber isolated nickel-chromium thermocouples, connected to a recording device, were inserted into fresh bovine rib bone blocks and kept in 20 ± 0.5 °C water at determined depths of 1.5 mm (cortical layer) and 7 mm (cancellous layer) and 1.0 mm away from the planned osteotomy site. Handpieces, angulated 24-32°, were mounted in a vertical drill stand, and standardized weights were attached to their tops to exert loads of 5, 8, 15 and 20 N. Irrigation volumes of 20, 50 and 80 ml/min were used for each load. Ten repetitions were conducted using new tips each time for each test condition. The Mann-Whitney-U test was used for statistical analysis (p < 0.05).
  
  
  RESULTS
  Both ultrasonic and sonic osteotomies were associated with significantly lower heat generation than conventional osteotomy (p < 0.01). Sonic osteotomy showed non-significantly lower heat generation than ultrasonic osteotomy. Generated heat never exceeded the critical limit of 47 °C in any system. Variation of load had no effect on heat generation in both bone layers for all tested systems. An increased irrigation volume resulted in lower temperatures in both cortical and cancellous bone layers during all tested osteotomies.
  
  
  CONCLUSIONS
  Although none of the systems under the conditions of the present study resulted in critical heat generation, the application of ultrasonic and sonic osteotomy systems was associated with lower heat generation compared to the conventional saw osteotomy. Copious irrigation seems to play a critical role in preventing heat generation in the osteotomy site.
authors.affiliation: Department of Oral and Maxillofacial Surgery (Head: Prof. Dr. Dr. Max Heiland; MD, DMD, PhD), University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany. Electronic address: a.rashad@uke.de.
authors.forename: Ashkan
authors.initials: A
authors.lastname: Rashad
authors.affiliation: Department of Neuroanatomy and Molecular Brain Research, Ruhr-University Bochum, Germany.
authors.forename: Pooyan
authors.initials: P
authors.lastname: Sadr-Eshkevari
authors.affiliation: Department of Oral and Maxillofacial Surgery (Head: Prof. Dr. Dr. Max Heiland; MD, DMD, PhD), University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
authors.forename: Max
authors.initials: M
authors.lastname: Heiland
authors.affiliation: Department of Oral and Maxillofacial Surgery (Head: Prof. Dr. Dr. Max Heiland; MD, DMD, PhD), University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Smeets
authors.affiliation: Department of Oral and Maxillofacial Surgery (Head: Prof. Dr. Dr. Max Heiland; MD, DMD, PhD), University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
authors.forename: Henning
authors.initials: H
authors.lastname: Hanken
authors.affiliation: Department of Oral and Maxillofacial Surgery (Head: Prof. Dr. Dr. Max Heiland; MD, DMD, PhD), University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Gröbe
authors.affiliation: Department of Oral and Maxillofacial Surgery (Head: Prof. Dr. Dr. Max Heiland; MD, DMD, PhD), University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
authors.forename: Alexandre T
authors.initials: AT
authors.lastname: Assaf
authors.affiliation: Department of Oral and Maxillofacial Surgery (Head: Prof. Dr. Dr. Max Heiland; MD, DMD, PhD), University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Köhnke
authors.affiliation: Department of Neuroanatomy and Molecular Brain Research, Ruhr-University Bochum, Germany.
authors.forename: Pouyan
authors.initials: P
authors.lastname: Mehryar
authors.affiliation: Department of Oral and Maxillofacial Surgery (Head: Prof. Dr. Dr. Max Heiland; MD, DMD, PhD), University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
authors.forename: Björn
authors.initials: B
authors.lastname: Riecke
authors.affiliation: Department of Oral and Maxillofacial Surgery (Head: Prof. Dr. Dr. Max Heiland; MD, DMD, PhD), University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Wikner
mesh_terms: D000818:Animals; D001831:Body Temperature / Q000502:physiology*; D001842:Bone and Bones / Q000502:physiology*; D000071556:Cancellous Bone / Q000502:physiology / Q000601:surgery; D002417:Cattle; D000071538:Cortical Bone / Q000502:physiology / Q000601:surgery; D006358:Hot Temperature; D010027:Osteotomy / Q000295:instrumentation*; D059745:Piezosurgery / Q000295:instrumentation*; D012272:Ribs / Q000502:physiology / Q000601:surgery; D013314:Stress, Mechanical; D007507:Therapeutic Irrigation / Q000379:methods; D013821:Thermometers; D059708:Ultrasonic Surgical Procedures / Q000295:instrumentation*
keywords: Conventional osteotomy; Heat generation; Intraosseous; Sonic system; Thermal damage; Ultrasonic surgery