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ePaper created 2016-02-02, 09:24:34 | version 1.38.0
37 37 4_2015 laser laser_research research I I 11 laser 3_2014 Figs. 12 & 13_Removal of the soft- granulation tissue from the split-shaped bone defect and the implant surface. Fig. 14_Application of the fibre tip parallelly to the implant surface into the depth of the periimplant bone defect. causal therapy in order to counteract a progression ofthedisease.2 Theremovalofsubgingivalconcre- ments and the bacterial biofilm of titanium im- plants is, however, hindered by various modifica- tions of the implant surfaces.3 Prosthetic options and superstructures often make the access to in- fected surfaces difficult. In this regard, decontam- ination or conditioning of the exposed implant surface is demanded in addition to the mechanical removal of the biofilm in order to optimise the re- moval of bacteria and their lipopolysaccharides fromthemicrostructuredimplantsurface.Forthis, a non-surgical therapy approach can be differen- tiated from a surgical one. The latter is obligatory in resective or regenerative procedures (guided bone regeneration, GBR). Contrarily, the removal of the biofilm as a preliminary to resective or re- generative procedure can be done surgically as well as after mobilisation of a mucoperiosteal flap under visual control.4 It should, however, then be noted that critical probing depths have not yet been defined for the therapy of periimplant infec- tions. These would help in deciding between non- surgical or surgical therapy approaches.5 An ade- quate plaque control by the patient and a suffi- cient recall system are basic prerequisites for all therapy concepts. _Laser application in the therapy of periimplant inflammations Laser applications have proven to be clinically effective in periodontology in our clinic. The high bactericidal potential of laser light in the gingival sulcus and the surrounding soft tissues is an ad- vantagethathasbeendescribedbyauthorssuchas Ben Hatit et al. 1996, Coffelt et al. 1997 and Moritz et al. 1997.6-8 It is imperative to note that the effects of differ- ent laser light wavelengths on implant surfaces vary. Thus, Nd:YAG laser must not be applied on ti- tanium implant surfaces. This laser would destroy theimplantsurfaces,withamacroscopicallyvisible welding effect. In contrast, Er:YAG lasers are suit- able for the application in close proximity to tita- nium implants, especially for cleaning and decont- aminating implant surfaces. Er:YAG lasers were in- troduced in 1974 by Zharikov et al. as solid state lasers with a wavelength of 2,940 nm in the near- to mid-infrared range.9 The special quality of this wavelength is that it concurs with the maximum absorption in water and is even 15 times higher than that of the CO2 laser. Depending on the phys- ical laser parameters chosen by the user (laser power, focus-tissue distance, application time, pulse rate and energy density), different biological processes occur in live tissues. In thermo-mechan- ical ablation, the removal of biological tissue is based on the fact that that the proportion of water inthetissuesundergoesarapidtransitionfromthe liquid to the gaseous state when absorbing ultra- short laser light impulses. Accompanied by a fast expansion of the water, the pressure becomes high enough to blast off and thus remove hard and soft tissue material.10 Fig. 11 Fig. 12 Fig. 13 Fig. 14