title: Increased intraosseous temperature caused by ultrasonic devices during bone surgery and the influences of working pressure and cooling irrigation.
abstract: OBJECTIVE
  The purpose of this study was to investigate the increases in intraosseous temperature generated by a modern ultrasonic device for bone surgery (UDBS) and the influences of working pressure and cooling irrigation on this temperature.
  
  
  METHODS
  Twenty human mandibular bone specimens (20x15x5 to 7 mm) were used; three vertical cuts were performed for a duration of 12 seconds per cut. Each bone specimen was machined with a different combination of working pressure (1.5, 2.0, 3.0, 4.0, or 6.0 N) and cooling irrigation (0, 30, 60, or 90 mL/min), and intraosseous temperatures were measured. Harmful temperature development was defined as an increase of more than 10°C for the 75th percentile and/or a maximum increase of more than 15°C. Cutting performance was also measured.
  
  
  RESULTS
  Harmless intraosseous temperature development was identified for working pressures of 1.5 N and 2.0 N with cooling irrigations of 30, 60, and 90 mL/min and for 3.0 N at 90 mL/min. The maximum temperature observed was 72°C (6.0 N with 60 mL/min). The mean cutting performance values were 0.21±0.02 mm/s for 6.0 N, 0.21±0.06 mm/s for 3.0 N, 0.20±0.01 mm/s for 4.0 N, 0.11±0.05 mm/s for 1.5 N, and 0.08±0.03 mm/s for 2.0 N.
  
  
  CONCLUSIONS
  To prevent tissue damage in dental bone surgery, a minimum coolant amount of 30 mL/min is recommended. The working pressure should be chosen with great care because of its significant influence on intraosseous temperature. Doubling of the working pressure from 1.5 to 3.0 N requires a tripling of the coolant (30 to 90 mL/min) to prevent tissue damage. A working pressure above 3.0 N did not result in improved cutting performance.
authors.affiliation: Institute of Anatomy, Dental School, Department of Prosthodontics, Propaedeutics and dental Materials, Christian-Albrechts University of Kiel, Kiel, Germany. f.birkenfeld@anat.uni-kiel.de
authors.forename: Falk
authors.initials: F
authors.lastname: Birkenfeld
authors.forename: Merlind Erika
authors.initials: ME
authors.lastname: Becker
authors.forename: Sönke
authors.initials: S
authors.lastname: Harder
authors.forename: Ralph
authors.initials: R
authors.lastname: Lucius
authors.forename: Matthias
authors.initials: M
authors.lastname: Kern
mesh_terms: D001831:Body Temperature; D003080:Cold Temperature; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible / Q000503:physiopathology / Q000601:surgery*; D011312:Pressure; D007507:Therapeutic Irrigation / Q000379:methods / Q000592:standards; D059708:Ultrasonic Surgical Procedures / Q000009:adverse effects*; D014465:Ultrasonics / Q000295:instrumentation*