Laser assisted removal of biofilms associated with periodontal and peri-implant diseases

The incidences of biofilm related periodontal and peri-implant diseases are high. It is expected that on average one out of five patients with dental implants will suffer from severe peri-implant disease. The existent clinical, radiographic and microbiological data do not favor any decontamination approach and fail to show the influence of a particular decontamination protocol on surgical therapy. The limited effectiveness of current treatment methods is due to hard-to-reach biofilm sites in the periodontal and peri-implant space and toxicity of effective antimicrobial agents to vital dental and implant tissues. Recently, contact laser therapy has been proposed as a very promising new tool for non-surgical biofilm treatment, capable of removing up to 99.9 % of biofilm under in vitro conditions, but the direct contact laser therapy may cause local dental or implant tissue damage. Our current research results suggest that photoacoustic irrigation with Er:YAG lasers can achieve excellent biofilm cleaning results on titanium surfaces (Hympanova et al., 2020, Terlep et al., 2021) without severe side effects. Currently a major stumbling block for a wider application of photoacoustic therapy is poor understanding of hydrodynamic streaming in constricted geometries of periodontal and peri-implant space. In the proposed project we will apply new laser techniques and modalities developed in our laboratories to treat patients with severe periodontitis and peri-implantitis. To deliver this the project will be divided into three interrelated subprojects. First basic understanding of the effect of local geometry on photoacoustic, photodynamic, and photothermic induced hydrodynamic flow will be determined in manufactured 3D volumes that will mimic constricted geometries of periodontal and peri-implant space. Second, the optimized laser parameters in constrained geometries will be used to examine the biofilm removal efficiency in vitro in hard to reach biofilm sites. In the third subproject the best in vitro laser parameter setups for biofilm removal will be used to treat patients with stage III periodontitis and peri-implantitis in a large randomized controlled clinical study. One of the partners in the project team (Fotona d.o.o.) develops and produces optoelectronic devices in particular laser technology and equipment for the dedicated dental use. This will allow us to test flexible laser schemes and to use very efficient super short and ultrashort laser pulse technology to boost hydrodynamic streaming in constrained geometries of periodontal and peri-implant space. The proposed laser modalities proved to be very successful in endodontic tooth root canal biofilm removal, but have not been tested yet in periodontal and implant therapy. The photoacoustic streaming with different laser modalities will be combined with different irrigants, laser induced photodynamic, and photothermal therapy. The proposed line of research will fill the existing gap in our knowledge of the cavitation physics in constrained geometries and improve microbiological knowledge of the effect of cavitation on biofilms with a clear medical application target. Better understanding of cavitation phenomena is crucial to appreciate the potential of cavitation; where we are now and how far we can reach with the new technological advancements. It will also give dental practitioners a better feel for the technology they are using and the theoretical background for an improved therapy. We are aiming to introduce a new laser tool for the general dentist, specialists of periodontology, and oral surgery to treat periodontitis and peri-implantitis. These two diseases cause major dental related health problems worldwide. We expect that less invasive non-surgical laser treatments of periodontitis and peri-implantitis in comparison to advanced conventional surgical treatment might reduce the treatment burden substantially.