title: Influence of parameters on root surface roughness following treatment with a magnetostrictive ultrasonic scaler: an in vitro study.
abstract: BACKGROUND
  This in vitro study aimed to evaluate the influence of different parameters, i.e., lateral force, instrument power setting, and the shape of the working tip, on the roughness of root surfaces following treatment with a magnetostrictive ultrasonic scaling device.
  
  
  METHODS
  The study sample comprised a total of 102 extracted human molars, premolars, canines, and incisors. The samples were randomly divided into 10 equal units of 10 each for treatment with the ultrasonic device at a lateral force of 0.5 N and 2.0 N, a low and high instrument power setting, and with a straight and angulated shaped working tip. Twenty samples were treated manually using curets at a lateral force of 0.5 N and 2.0 N. Two samples were left untreated as controls. The mean (Ra) and maximum (Rmax) surface roughness of each sample was recorded. The statistical analysis was performed using analysis of variance (three-way ANOVA) at a level of significance of 5% (P < 0.05).
  
  
  RESULTS
  The mean surface roughness (+/-SD) using different parameters ranged from 0.6 +/- 0.1 microm to 1.8 +/- 0.3 microm. The maximum surface roughness (+/-SD) was between 4.8 +/- 1.3 microm and 17.2 +/- 4.3 microm. The mean surface roughness (+/-SD) for samples treated with curets at a lateral force of 0.5 N was 0.5 +/- 0.0 microm and 0.4 +/- 0.1 microm at 2.0 N. The maximum surface roughness (+/-SD) was 3.7 +/- 0.8 microm at 0.5 N and 3.9 +/- 1.4 microm at 2.0 N.
  
  
  CONCLUSIONS
  The findings of the present study indicate that the shape of the working tip and the lateral force significantly influence the mean and maximum surface roughness of root surfaces treated with a magnetostrictive ultrasonic scaling device. At any specific parameter, the surface roughness was significantly higher for the ultrasonic scaling device as compared to the hand curet.
authors.affiliation: Department of Operative Dentistry and Periodontology, Ludwig-Maximilians-University, Munich, Germany. mfolwa@dent.med.uni-muenchen.de
authors.forename: Matthias
authors.initials: M
authors.lastname: Folwaczny
authors.forename: Ute
authors.initials: U
authors.lastname: Merkel
authors.forename: Albert
authors.initials: A
authors.lastname: Mehl
authors.forename: Reinhard
authors.initials: R
authors.lastname: Hickel
mesh_terms: D000704:Analysis of Variance; D003475:Curettage / Q000295:instrumentation; D012534:Dental Scaling / Q000295:instrumentation*; D004867:Equipment Design; D006801:Humans; D008280:Magnetics / Q000295:instrumentation; D013314:Stress, Mechanical; D013499:Surface Properties; D014092:Tooth Root / Q000473:pathology*; D014464:Ultrasonic Therapy / Q000295:instrumentation*