title: Temperature Development on the External Root Surface During Laser-Assisted Endodontic Treatment Applying a Microchopped Mode of a 980 nm Diode Laser.
abstract: OBJECTIVE
  The aim of this article was to investigate the temperature increase of the external root surface during laser-assisted endodontic treatment using a diode laser (980 nm) in a microchopped mode.
  
  
  METHODS
  Ten freshly extracted, human maxillary incisors with mature apices were collected, prepared to size F4 at working length (ProTaper; Dentsply Maillefer, Ballaigues, Switzerland), mounted to a holder, and irradiated (using spiral movements in coronal direction) with a diode laser (GENTLEray 980 Classic Plus; KaVo, Biberach, Germany) with a 200 μm fiber in four different treatment groups: Group 1 (control group) was irradiated in six cycles of 5-sec irradiation/20-sec pause with 2.5 W in the pulse mode. Groups 2 to 4 were irradiated at six cycles of 5-sec irradiation/20-sec pause in the microchopped mode (Group 2-1.6 W; Group 3-2.0 W; Group 4-2.5 W). The applied mode was 25 ms on/25 ms off. Within the on period, the laser delivered an intermittent sequence of energy complexes and the maximum output was equal to the nominated output of the device (12 W). Canals were kept moist by sterile saline irrigation in between irradiations, and temperature changes were continuously measured using a thermal imaging camera. Recordings were analyzed by a mixed model (analysis of variance [ANOVA] for repeated measurements).
  
  
  RESULTS
  The highest mean of temperature rise, 1.94°C ± 1.07°C, was measured in Group 4, followed by Group 3 (1.74°C ± 1.22°C) and Group 2 (1.58°C ± 1.18°C). The lowest increase occurred in Group 1 (1.06°C ± 1.20°C). There was a significant difference (p = 0.041) between the groups. Significant differences were found between Groups 1 and 4 (p = 0.007) and 1 and 2 (p = 0.035). In addition, a marginally significant difference between Groups 1 and 2 (p = 0.052) was noted. There was no significant difference between Groups 2, 3, and 4. Despite the low mean values reported, the highest temperature increase (+5.7°C) was measured in one of the specimens of treatment Group 2 at the middle third.
  
  
  CONCLUSIONS
  Under the conditions used and within the limitations of the study, the microchopped diode laser irradiation is a safe possible treatment option in laser-assisted endodontic treatment, concerning the temperature elevation on the external root surface.
authors.affiliation: 1 Private Practice , Vienna, Austria .
authors.forename: Franziska
authors.initials: F
authors.lastname: Beer
authors.affiliation: 2 Department of Endodontics, National and Kapodestrian University of Athens , Athens, Greece .
authors.forename: Eleftherios Terry R
authors.initials: ET
authors.lastname: Farmakis
authors.affiliation: 3 Unit-Division of Dental Student Training and Patient Care, School of Dentistry, Medical University of Vienna , Vienna, Austria .
authors.forename: Josip
authors.initials: J
authors.lastname: Kopic
authors.affiliation: 4 Division of Conservative Dentistry and Periodontology, School of Dentistry, Medical University of Vienna , Vienna, Austria .
authors.forename: Christoph
authors.initials: C
authors.lastname: Kurzmann
authors.affiliation: 4 Division of Conservative Dentistry and Periodontology, School of Dentistry, Medical University of Vienna , Vienna, Austria .
authors.forename: Andreas
authors.initials: A
authors.lastname: Moritz
mesh_terms: D000704:Analysis of Variance; D003786:Dental Pulp Cavity / Q000528:radiation effects*; D004708:Endodontics / Q000379:methods; D006358:Hot Temperature; D006801:Humans; D066298:In Vitro Techniques; D007180:Incisor / Q000528:radiation effects; D054023:Lasers, Semiconductor / Q000627:therapeutic use*; D028022:Low-Level Light Therapy / Q000009:adverse effects / Q000379:methods*; D014081:Tooth Extraction; D014092:Tooth Root / Q000528:radiation effects*
keywords: chopped mode; diode laser; endodontic treatment; microchopped mode; temperature