title: Effect of an Er:YAG laser on periodontally involved root surfaces: an in vivo and in vitro SEM comparison.
abstract: OBJECTIVE
  The recently introduced Er:YAG laser seems to be a promising alternative in periodontal treatment due to its thermo-mechanical ablation mechanism. The present study attempted to compare the effects of an Er:YAG laser on periodontally involved root surfaces at different power settings in vivo and in vitro using scanning electron microscopic (SEM) observations.
  
  
  METHODS
  Forty single rooted teeth (160 surfaces), with advanced periodontal destruction that were scheduled for extraction, were divided into two groups of 80 each which were treated in vivo (group A) and immediately after extraction in vitro (group B) using one of the following energy settings: 120, 140, 160, and 180 mJ at 10 Hz (71, 83, 94, and 106 J/cm(2)/pulse). The morphological changes on the treated root surfaces were evaluated using scanning electron microscopic (SEM) observations to assess the laser induced ultrastructural changes. The severity of the changes was evaluated according to an arbitrary scale in 7 degrees [1-7]. Untreated peripheral areas served as control.
  
  
  RESULTS
  All surfaces treated in vitro (group B) showed visible crater-like defects with notch-edged borders. The depth of the surface damages varied with the power applied and was localized into cementum at energy settings of 120-160 mJ but also reached dentine at 180 mJ. Compared to that, all in vivo (group A) treated surfaces showed a homogeneous and smooth root surface morphology. The surface alterations were not related to the used energy setting.
  
  
  CONCLUSIONS
  The results of the present study showed that the clinical use of an Er:YAG laser resulted in a smooth root surface morphology, even at higher energy settings. The results also seem to indicate that calculus removal can be selectively done in vivo.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Ludwig Maximilians University, Lindwurmstrasse 2a, 80337 Munich, Germany. FSchw72@aol.com
authors.forename: F
authors.initials: F
authors.lastname: Schwarz
authors.forename: N
authors.initials: N
authors.lastname: Pütz
authors.forename: T
authors.initials: T
authors.lastname: Georg
authors.forename: E
authors.initials: E
authors.lastname: Reich
mesh_terms: D003728:Dental Calculus / Q000532:radiotherapy* / Q000648:ultrastructure*; D003739:Dental Cementum / Q000528:radiation effects / Q000648:ultrastructure; D012534:Dental Scaling; D004871:Erbium / Q000627:therapeutic use*; D006801:Humans; D066298:In Vitro Techniques; D053685:Laser Therapy; D008855:Microscopy, Electron, Scanning; D010510:Periodontal Diseases / Q000473:pathology* / Q000532:radiotherapy*; D011874:Radiometry; D012044:Regression Analysis; D014081:Tooth Extraction; D014092:Tooth Root / Q000528:radiation effects* / Q000648:ultrastructure*
chemical_list: D004871:Erbium