Objectives: Aim of this study was to compare the soft tissue response to implant abutments made of titanium, zirconia, zirconia veneered with feldspar ceramics and PEEK by various clinical, histological, microbiological, and molecular biological markers in an experimental model. Materials and Methods:A total of 40 experimental one-piece healing abutments of four different materials were mounted on bone level implants in 20 volunteering patients (split-mouth design). After a three-month period of open healing, clinical parameters at the abutments were assessed and adjacent mucosa was sampled for inflammatory cytokine mRNA concentrations and histological analysis by a novel method. In addition, PISF samples were obtained for the analysis of periodontopathogenic bacteria counts and active MMP-8 levels. Marginal bone level change was measured by intra oral radiographs.Results: Abutments of the different materials did not exhibit significant differences regarding clinical parameters, pathogenic bacteria counts or pro-inflammatory cytokine concentrations. Likewise, no significant differences were detected regarding soft tissue morphology or bone level change. Compared to titanium abutments, significantly less mononuclear inflammatory cells were detected in the mucosa at abutments made of zirconia veneered with feldspar ceramics.Conclusions: All examined abutment materials exhibited a similar soft tissue response compared to titanium and histological data did not reveal early signs of elevated inflammation caused by PEEK-and feldspar-veneered zirconia abutments. Due to the short observation period and the small sample size, a final conclusion on the long-term suitability of those abutment materials cannot be drawn. However, based on the presented data, we consider further studies on that subject as appropriate.

Objectives To introduce a standardized and less invasive clinical model that provides histological information on the abutment–mucosa interface in humans. Materials and methods New experimental healing abutments were left in an open healing position on bone‐level implants in the interforaminal region of the mandibles in six edentulous patients. The one‐piece abutments were hollow cylinder‐shaped with two lateral openings that allow for ingrowth of the peri‐implant mucosa into the central abutment cavity. After three months of healing, abutments and ingrown mucosa were sampled and processed for histological analysis in a non‐separated resin‐embedding technique. To test the validity of the new model, the ingrown tissue was compared to the peri‐implant mucosa around the same samples. Results None of the experimental abutments exhibited signs of failure, and all samples showed mucosal ingrowth to the inner‐abutment cavity. Comparison of ingrown tissue and peri‐implant mucosa revealed no significant differences regarding the traits: tissue morphology, quality of collagen fibers, and adherence to the abutment. Ingrown mucosa exhibited a tendency for higher leukocyte infiltration. Conclusions The presented model is a promising approach to reduce invasiveness during the sampling process for human non‐separated abutment biopsies.

Different environmental conditions may lead to diverse morphological, behavioral and physiological adaptations of different populations of the same species. Lighting conditions, for example, vary vastly especially between aquatic habitats, and have been shown to elicit adaptations. The availability of short-wave ultraviolet (UV) light is especially fluctuating, as UV wavelengths are attenuated strongly depending on water properties. The island of North Uist, Scotland, comprises two differential habitat types, tea-stained and clear-water lakes, varying considerably in UV transmission. In previous studies, wild-caught three-spined stickleback Gasterosteus aculeatus populations (three populations of each habitat type) were tested with respect to their shoaling and mate preferences for fish viewed under UV-present and UV-absent conditions. The results revealed a habitat-dependent preference of UV cues during shoal choice (tea-stained populations: preference for UV-absent condition in tea-stained water; clear-water populations: no preference in clear-water) but an overall preference for UV-present conditions during mate choice. To assess genetic influences on these behavioral patterns, similar experiments were conducted with lab-bred F1-generations of the same stickleback populations that were raised in a common environment (i.e. standardized clear-water conditions). Offspring of sticklebacks from tea-stained lakes tended to prefer shoals viewed under UV-absent conditions (only in tea-stained water), while sticklebacks from clear-water lakes showed a significant preference for the shoal viewed under UV-present conditions in clear-water but not in tea-stained water. Mate-preference experiments demonstrated that females from the tea-stained lakes significantly preferred and females from the clear-water lakes preferred by trend the male viewed under UV-present conditions in the clear-water treatment. The results for both shoaling- and mate-preference tests were largely similar for wild-caught and lab-bred sticklebacks, thus hinting at a genetic basis for the preference patterns.

ObjectivesPrevious studies have indicated a progressive internal bacterial colonization of implants and possible implications for peri‐implant bone loss. The aim of this study was to evaluate a decontamination protocol, two disinfectants, and a sealant for their ability to prevent such a colonization.Materials and MethodsBacterial samples were harvested from the peri‐implant sulcus (external) and following abutment removal from the implant cavity (internal) during routine supportive peri‐implant care in 30 edentulous patients 2 years after they had obtained two implants. In a split‐mouth design, implants were randomly assigned to receive either internal decontamination alone (10% H2O2, brush) or additional placement of either sealant (GS), disinfectant agent (CHX‐varnish) or disinfectant gel (1% CHX‐gel), in the internal cavity before remounting of abutment/suprastructure. Twelve months later, internal and external sampling was repeated. Total bacterial counts (TBCs) were determined using real‐time PCR in a total of 240 samples (eight per patient).ResultsTotal bacterial counts in the internal cavity significantly reduced overall treatment modalities 1 year after the treatments (4.0 [2.3–6.9]‐fold reduction; p = .000). No significant differences between the four treatment types were found (p = .348). Comparison of internal and external sampling points revealed significant correlation (R2 = .366; p = .000) with systematically higher TBC counts in external samples.ConclusionsWithin the limitations of the present study, it can be concluded that the use of disinfectant agents or a sealant did not show an additional benefit in the prevention of internal bacterial colonization of implants compared to a decontamination protocol alone.