Abstract: Objectives This study aimed to evaluate the influence of vestibuloplasty on the clinical success and survival of dental implants in head and neck tumor patients. Materials and methods A retrospective single-center study was conducted. All patients received surgical therapy of a tumor in the head or neck and underwent surgical therapy and, if necessary, radiotherapy/radiochemotherapy. Patients with compromised soft tissue conditions received vestibuloplasty using a split thickness skin graft and an implant-retained splint. Implant survival and success and the influence of vestibuloplasty, gender, radiotherapy, and localizations were evaluated. Results A total of 247 dental implants in 49 patients (18 women and 31 men; mean age of 63.6 years) were evaluated. During the observation period, 6 implants were lost. The cumulative survival rate was 99.1% after 1 year and 3 years and 93.1% after 5 years for patients without vestibuloplasty, compared to a survival and success rate of 100% after 5 years in patients with vestibuloplasty. Additionally, patients with vestibuloplasty showed significantly lower peri-implant bone resorption rates after 5 years (mesial: p = 0.003; distal: p = 0.001). Conclusion This study demonstrates a high cumulative survival and success rate of dental implants after 5 years in head and neck tumor patients, irrespective of irradiation. Patients with vestibuloplasty showed a significantly higher rate of implant survival and significantly lower peri-implant bone resorption after 5 years. Clinical relevance Vestibuloplasty should always be considered and applied if required by the anatomical situations to achieve high implant survival/success rates in head and neck tumor patients

Abstract: Synchrotron real-time radioscopy and in situ microtomography are the only techniques providing direct visible information on a micrometre scale of local deformation in the implant-abutment connection (IAC) during and after cyclic loading. The microgap formation at the IAC has been subject to a number of studies as it has been proposed to be associated with long-term implant success. The next step in this scientific development is to focus on the in situ fatigue procedure of two-component dental implants. Therefore, an apparatus has been developed which is optimized for the in situ fatigue analysis of dental implants. This report demonstrates both the capability of in situ radioscopy and microtomography at the ID19 beamline for the study of cyclic deformation in dental implants. The first results show that it is possible to visualize fatigue loading of dental implants in real-time radioscopy in addition to the in situ fatigue tomography. For the latter, in situ microtomography is applied during the cyclic loading cycles in order to visualize the opening of the IAC microgap. These results concur with previous ex situ studies on similar systems. The setup allows for easily increasing the bending force, to simulate different chewing situations, and is, therefore, a versatile tool for examining the fatigue processes of dental implants and possibly other specimens

Abstract: MRI is increasingly used as a diagnostic tool for visualising the dentoalveolar complex. A comprehensive review of the current indications and applications of MRI in the dental specialities of orthodontics (I), endodontics (II), prosthodontics (III), periodontics (IV), and oral surgery (V), pediatric dentistry (VI), operative dentistry is still missing and is therefore provided by the present work. The current literature on dental MRI shows that it is used for cephalometry in orthodontics and dentofacial orthopaedics, detection of dental pulp inflammation, characterisation of periapical and marginal periodontal pathologies of teeth, caries detection, and identification of the inferior alveolar nerve, impacted teeth and dentofacial anatomy for dental implant planning, respectively. Specific protocols regarding the miniature anatomy of the dentofacial complex, the presence of hard tissues, and foreign body restorations are used along with dedicated coils for the improved image quality of the facial skull. Dental MRI poses a clinically useful radiation-free imaging tool for visualising the dentoalveolar complex across dental specialities when respecting the indications and limitations

Abstract: Background Aim of the pilot study was the histologic classification of the inflamed peri-implant soft tissue around ceramic implants (CI) in comparison with titanium implants (TI). Methods Peri-implant tissue were retrieved from 15 patients (aged 34 to 88 years, seven males/eight females) with severe peri-implantitis (eight CI, seven TI). The peri-implant soft tissue samples were retrieved from the sites during scheduled removal of the implant and prepared for immunohistochemical analysis. Monoclonal antibodies (targeting CD3, CD20, CD138, and CD68) were used to identify T- and B-cells, plasma cells and macrophages. Quantitative assessment was performed by one histologically trained investigator. Linear mixed regression models were used. Results A similar numerical distribution of the cell population was found in peri-implantitis around CI compared with TI. CD3 (TI, 17% to 85% versus CI, 20% to 70% of total cell number) and CD138 (TI, 1% to 73% versus CI, 12% to 69% of total cell number) were predominantly expressed. Notably, patient-individual differences of numerical cell distribution were detected. Co-localization of B- and T-lymphocytes was observed. Conclusions Peri-implantitis around CI in comparison with TI seems to have a similar histological appearance. Differences in cellular composition of peri-implantitis lesions might also depend on the patient's specific immune status and not only on the material used

Abstract: State-of-the art, two-piece dental implants made from titanium alloys exhibit a complex micromechanical behavior under dynamical load. Its understanding, especially the formation of microgaps, is of crucial importance in order to predict and improve the long-term performance of such implants. Microgap formation in a loaded dental implant with a conical implant-abutment connection can be studied and quantified by synchrotron radiography with micrometer accuracy. Due to the high costs and limited access to synchrotron radiation sources, alternative approaches are needed in order to depict the microgap formation. Therefore, synchrotron radiography is used in this article to validate a simple finite element model of an experimental conical implant design. Once validated, the model is in turn employed to systematically study the microgap formation developed in a variety of static load scenarios and the influence of the preload of abutment screw on the microgap formation. The size of the microgap in finite element analysis (FEA) simulations is consistent with that found in in-vitro experiments. Furthermore, the FE approach gives access to more information such as the von-Mises stresses. It is found that the influence of the abutment screw preload has only a minor effect on the microgap formation and local stress distribution. The congruence between FE simulations and in-vitro measurements at the micrometer scale underlines the validity and relevance of the simple FE method applied to study the micromovement of the abutment and the abutment screw preload in conical implant-abutment connections under load