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When the SARS-CoV-2 pandemic started,[1] science came to the immediate attention of the broad public. People and politicians were hanging on every word of medical doctors, virologists, molecular biologists, data scientists and many others in the hope of finding other protective measures than those used for centuries such as basic hygiene, distance, or quarantine. Here, at the Institute of Chemistry and Biotechnology at the Zurich University of Applied Sciences (ZHAW) we were also willing to provide scientific solutions to overcome the pandemic. Together with our partners from industry, we contributed to the development of a Swiss vaccine, are working on filters for active ventilated full protective suits and are developing tests to show the efficacy and safety of an active antiviral textile that allows controlled virus inactivation through an electrochemical reaction by applying a small current.

Periodontitis is a very common health problem caused by formation of pathogenic bacterial biofilm that triggers inflammation resulting in either reversible gingivitis or irreversible periodontal hard and soft tissue damages, leading to loss of teeth when left untreated. Commensal bacteria play an important role in oral health in many aspects. Mainly by colonizing oral tissues, they (i) contribute to maturation of immune response, and (ii) foreclose attachment of pathobiont and, therefore, prevent from infection. The main goal of the study was to investigate if blocking of receptors on a commensal biofilm can prevent or reduce the attachment of pathogenic strains. To do so, biofilm produced by commensal Streptococcus sanguinis was treated with whole cell lysate of pathobionts Fusobacterium nucleatum or Porphyromonas gingivalis, followed by incubation with respective strain(s). The study revealed significant reduction in pathobiont adhesion to lysate-treated commensal biofilm. Therefore, adhesion of pathobionts onto the lysate-blocked biofilm was hindered; however, not completely eliminated supporting the idea that such approach in the oral cavity would benefit the production of a well-balanced and healthy bioactive interface.

The aim of the present study was to evaluate a new multi-phosphonate surface treatment (SurfLink®) in an unloaded sheep model. Treated implants were compared to control implants in terms of bone to implant contact (BIC), bone formation, and biomechanical stability. The study used two types of implants (rough or machined surface finish) each with either the multi-phosphonate Wet or Dry treatment or no treatment (control) for a total of six groups. Animals were sacrificed after 2, 8, and 52 weeks. No adverse events were observed at any time point. At two weeks, removal torque showed significantly higher values for the multi-phosphonate treated rough surface (+32% and +29%, Dry and Wet, respectively) compared to rough control. At 52 weeks, a significantly higher removal torque was observed for the multi-phosphonate treated machined surfaces (+37% and 23%, Dry and Wet, respectively). The multi-phosphonate treated groups showed a positive tendency for higher BIC with time and increased new-old bone ratio at eight weeks. SEM images revealed greater amounts of organic materials on the multi-phosphonate treated compared to control implants, with the bone fracture (from the torque test) appearing within the bone rather than at the bone to implant interface as it occurred for control implants.

Stefan StübingerCompetence Center for Applied Biotechnology and Molecular Medicine, University of Zürich, Zürich, SwitzerlandAbstract: The erbium-doped yttrium aluminium garnet (Er:YAG) laser has emerged as a possible alternative to conventional methods of bone ablation because of its wavelength of 2.94 μm, which coincides with the absorption peak of water. Over the last decades in several experimental and clinical studies, the widespread initial assumption that light amplification for stimulated emission of radiation (laser) osteotomy inevitably provokes profound tissue damage and delayed wound healing has been refuted. In addition, the supposed disadvantage of prolonged osteotomy times could be overcome by modern short-pulsed Er:YAG laser systems. Currently, the limiting factors for a routine application of lasers for bone ablation are mainly technical drawbacks such as missing depth control and a difficult and safe guidance of the laser beam. This article gives a short overview of the development process and current possibilities of noncontact Er:YAG laser osteotomy in oral and implant surgery.Keywords: carbonization, laser osteotomy, ablation, dental implants

ABSTRACTObjective:The purpose of this study was to examine for the first time the feasibility of performing complete osteotomy of sheep tibia using a computer-guided CO2-laser osteotome, and to examine bone healing under functional loading. Background Data:Bone cutting without aggravating thermal side effects has been demonstrated with scanning CO2-laser osteotomy. Further research is necessary to develop a clinically usable laser osteotome, which may allow new types of bone surgical procedures. Materials and Methods:The scanning parameters for performing tibial osteotomies were determined in preliminary ex vivotrials. Osteotomies were performed in the mid-diaphysis of sheep tibia using either the prototype laser osteotome (osteoLAS, study group; n 12), or an oscillating saw (control group; n 12). Both groups were divided into two subgroups each (n 6), and the two groups were sacrificed after 4 and 12 wk. Radiographs were taken postoperatively and after 4, 8, and 12 wk to compare the course of bone healing. Results:Laser osteotomies of sheep tibia up to a depth of 20 mm were possible without visible thermal damage to the bone. A sequential PC-controlled cut geometry with artificial widening of the osteotomy gap was required for a complete osteotomy. Both clinically and radiologically, the laser and control groups showed undisturbed primary gap healing. Bone healing was similar and undelayed after both laser osteotomy and osteotomy done by mechanical saw. Conclusions:Osteotomy of multi-layered bones with a scanning CO2-laser demonstrates clinical and radiological healing patterns comparable to those seen with osteotomy done by standard mechanical instruments. It is, however, a technically demanding procedure, and complete laser osteotomies of long bones are only reasonable in bones with a diameter <20 mm, which will likely restrict the use of this technique to bones 7–10 mm thick. Through the use of computer guidance, extremely precise osteotomies and sophisticated cut geometries are possible using this technique. For practical applications, precise control of the depth of laser cutting and easier manipulation of the osteotome are required. [ABSTRACT FROM AUTHOR]

Objective:This case report was aimed at primary clinical experience concerning surgical extraction of a displaced tooth with the help of the Er:YAG laser based on refined computer-assisted presurgical planning. Methods:The case refers to the extraction of a displaced maxillary canine in a female patient. For the osteotomy, a pulsed Er:YAG laser was applied with pulse energy of 500 mJ, pulse duration of 250 µsec and pulse frequency of 12 Hz. The fiber tip (1000 µm) was kept with a 1–2 mm distance to the bone surface. Refined presurgical computer-assisted planning was performed with regard to minimization of bone loss, especially for the sake of preservation of the alveolar ridge. Based on a detailed three-dimensional (3D) reconstruction of the patient's anatomy, dynamical simulations of a buccal and a palatinal variant of access osteotomy were provided. Additionally, a volumetric profile of bone tissue quality based on Hounsfield values was generated. Results:By means of the 3D reconstruction and the tissue quality profile, both bone thickness and quality was evaluated as superior in the palatinal rather than in the vestibular part. Therefore, a classical buccal access window was chosen. The laser osteotomy allowed an exact cut geometry without any thermal damage and merely minimal bone loss. Conclusion:The enhanced possibilities by laser osteotomy allowed for full exploitation of presurgical planning. As regards the actual case, computer-assisted planning was of benefit for an appropriate choice of access osteotomy by enabling evaluation of the consistency of the bony structures. [ABSTRACT FROM AUTHOR]