The effect of therapeutic and nd:yag laser as an adjunct treatment modality in periodontal therapy

Abstract: Laser irradiation has been proposed as an adjunct to conventional scaling and root planing in the treatment of periodontitis. However, the reported outcomes of studies to date are contradictory and the literature provides limited evidence to support an additional benefit of laser application. The overall aim of the present thesis was to explore the potential of adjunctive application of therapeutic and surgical lasers to improve treatment outcomes, expressed in terms of clinical, radiographic and immunological parameters. The present thesis is based on a series of four clinical studies of patients with moderately severe periodontitis, treated by scaling and root planing. Two different types of dental laser were investigated. Therapeutic lasers, which are claimed to stimulate cell regeneration and boost the immune system, were investigated in studies I and II: the general effect was investigated in Study I, while Study II compared the difference between gas and diode lasers in the same spectrum, in order to evaluate the importance of the length of coherence in biostimulation. In studies III and IV, the surgical Nd:YAG laser, which is usually applied for sulcular debridement and pocket decontamination, was evaluated in a novel approach. The test procedure comprised one single application of the laser with water coolant after conventional scaling and root planing. In study III, the outcome was evaluated after 3 months and in Study IV the long term outcome was evaluated, at least one year post-treatment. The split mouth design was used in all four studies. Study I showed a better clinical outcome on the laser treated side and some improvement in immunological parameters. The results of Study II support the hypothesis that a laser with a long length of coherence is superior to one of a shorter length, although both lasers had some positive clinical effect. In Study III a single application of the Nd:YAG laser as an adjunct to scaling and root planing improved the short-term outcome and Study IV confirmed that this improvement was sustained. In conclusion, the results of these studies confirm the potential role of laser irradiation as a non-invasive adjunctive to scaling and root planing in the treatment of periodontitis.