In vivo and in vitro Effects of an Er:YAG Laser, a GaAlAs Diode Laser, and SRP on Periodontally Diseased Root Surfaces. A Comparative Histologic Study

Objectives: The aim of the present histologic study was to compare the in vivo and in vitro effects of an Er:YAG laser, a diode laser and SRP on periodontally diseased root surfaces. Methods: 24 single rooted teeth, considered for extraction due to severe periodontal destruction, were included in the study. Prior to extraction all mesial root surfaces were randomly assigned to the following groups: (1) Er:YAG laser combined with a calculus detection system with fluorescence induced by 655 nm InGaAsP diode laser radiation (160 mJ/pulse, 10 Hz) (ERL), or (2) GaAlAs diode laser (1.8 W)(DL), or (3) SRP using hand instruments. Immediately after extraction, all distal root surfaces were treated with the same instruments under standardized conditions. For light microscopic investigation, a plastic embedding technique was used to cut the undecalcified roots into 30 µm thick crossections. The following parameters were recorded: root surface morphology, remaining debris and thermal side effects. Results: Root surfaces instrumented with both, ERL in vivo and DL in vitro exhibited no detectable surface alterations. In contrast, ERL scaling in vitro and SRP in vivo/in vitro produced superficial microchanges in root cementum. However, irradiation with DL in vivo caused severe damages to the root surface (i.e. crater formation). There were no signs of thermal side effects in all laser treated groups. ERL provided subgingival calculus removal on a level equivalent to that provided by SRP. DL was unsuitable for calculus removal, since macroscopic inspection revealed the presence of large amounts of subgingival calculus. Conclusions: The present in vivo results showed that (i) ERL, combined with a fluorescent calculus detection system, provided a selective subgingival calculus removal on a level equivalent to that provided by SRP, and (ii) DL, using this power output, was unsuitable for calculus removal and altered the root surface in an undesirable manner.