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Conventional anastomoses with interrupted sutures are challenging and inevitably associated with trauma to the vessel walls. The goal of this study was to evaluate a novel alternative adhesive-based suture-free anastomosis technique that uses an intraluminal stent. Overall, 120 porcine coronary vessels were analyzed in an ex vivo model and were examined for their mechanical (n = 20 per cohort) and hydrostatic strength (n = 20 per cohort). Anastomoses were made using the novel VIVO adhesive with an additional intraluminal nitinol stent and was compared to interrupted suture anastomosis and to native vessels. Sutureless anastomoses withstood pressures 299 ± 4.47 [mmHg] comparable to native vessels. They were performed significantly faster 553.8 ± 82.44 [sec] (p ≤ 0.001) and withstood significantly higher pressures (p ≤ 0.001) than sutured anastomoses. We demonstrate that the adhesive-based anastomosis can also resist unphysiologically high longitudinal tensile forces with a mean of 1.33 [N]. Within the limitations of an in vitro study adhesive-based suture-free anastomosis technique has the biomechanical potential to offer a seamless alternative to sutured anastomosis because of its stability, and faster handling. In vivo animal studies are needed to validate outcomes and confirm safety.

The high incidence rate of periodontal bone defects and the unique regeneration characteristics of periodontal bone require a specially designed animal jawbone defect model to evaluate the appropriate periodontal bone regeneration procedure. The aim of the present investigation was to develop a reproducible, quantifiability and easy to implement periodontitis-like intrabony maxillary defect model in rats that allows investigation on bone regeneration. Ten upper jaws of rats were analyzed by micro-CT (µCT) imaging according to the bone dimensions for an appropriate position of a three-walled bone defect. A total of 30 intrabony defects measuring 1 × 1 × 1 mm were created using a split-mouth model on the palatal side of the maxillary first molar using ultrasonic surgery. 6 bone defects served as control. 20 bone defects were filled with alloplastic and xenogeneic particulate bone graft, and µCT scans were performed to verify bone regeneration of the periodontitis-like three-walled bone defect after 12 weeks. After 12 weeks, the µCT examinations showed sufficient bone regeneration of the artificially created periodontitis-typical defects. The µCT images revealed no morphological differences between xenogeneic and alloplastic bone substitute material. No restrictions for the animals, dehiscences or wound healing disorders were evident during the entire study period. The presented minimally invasive rat model with bilateral periodontitis-typical intrabony defects palatal to the first upper molar represents a favorable model for the investigation of regenerative osseous processes within a small defect.

Implant outcomes in comparison to a natural tooth in a rat model using systemic alendronate and zoledronate acid drug administrations were assessed. Fifty-four Sprague–Dawley rats were randomly allocated into two experimental groups (drug application of zoledronic acid; 0.04 mg/kg intravenously once a week and alendronic acid; 0.2 mg/kg subcutaneously five times a week) and one control group with 18 animals in each group. Drug delivery was conducted for a period of 4 months. After 4 weeks either a zirconia or a titanium implant was immediately inserted in the socket of the first molar of the upper jaw. In vivo investigations included host inflammatory parameters and the implant survival and success rates for up to 3 months. Material incompatibilities against titanium and zirconia nanoparticles were evaluated in vitro after stimulation of rat spleen cells. In vivo, IL-6 release around titanium implants demonstrated significantly higher values in the control group (p = 0.02) when compared to the zoledronic acid group. Around the natural tooth without drug administration, the control group showed higher IL-6 values compared with the alendronic acid group (p = 0.01). In vitro, only lipopolysaccharide and not the implant’s nanoparticles stimulated significant IL-6 and TNFα production. In terms of the primary aim of in vivo and in vitro IL-6 and TNFα measurements, no implant material was superior to the other. No significant in vitro stimulation of rat spleen cells was detected with respect to titanium oxide and zirconium oxide nanoparticles.

With the increasing use of dental implants in patients undergoing extensive mandibular reconstructions, it is crucial to understand how soft tissues react in different implantation contexts. The aim was to compare the behavior of the soft tissues surrounding zirconia implants to that of the soft tissues surrounding natural teeth in terms of cytokine levels in patients who had undergone various microvascular flap procedures for jaw reconstruction. Due to anatomical deviations after flap surgery, such as thick skin paddles, the possibility of fixed implant dentures in patients with bony flaps is rare. Therefore, these patients are often treated with removable dentures. In this prospective observational study ten patients with a total of six fibula flaps and four deep circumflex iliac artery (DCIA) flaps underwent reconstruction in the lower and upper jaws using vascularized bone flaps, and were treated with a total of 41 zirconia implants. The cytokine levels in the crevicular fluid were analyzed in terms of the interleukin-1 beta (IL-1b) and matrix metalloproteinase-8 (MMP-8) levels up to one-year follow-up. The implant survival and success rates were also investigated up to one year. No significant differences in IL-1b were found between natural teeth and ceramic implants. After six months, MMP-8 levels of the natural teeth of a patient treated with DCIA flaps were once significantly lower when compared to the ceramic implants inserted into fibula flaps ( p  = 0.001). The overall survival and success rates were 100 and 76.83%, respectively. For the fibula group, the survival and success rates were 100 and 72.55%, respectively, and for the DCIA group, they were 100 and 81.12%. Zirconia implants and natural teeth showed comparable cytokine levels in the crevicular fluid. Nevertheless, implant treatment with extensive microvascular jaw reconstructions affected the success rates in the present study.

Head and neck reconstruction with microvascular free flaps is frequently performed in smokers. Smoking causes various alterations in the cardiovascular system. The aim of this study was to investigate the effects of smoking on flap perfusion as a critical factor for flap survival. A total of 370 patients reconstructed with a radial free forearm flap (RFFF) or anterolateral thigh flap (ALTF) in the head and neck region between 2011 and 2020 were retrospectively analyzed. Flap perfusion measurements with the O2C tissue oxygen analysis system were compared between nonsmokers, light smokers (< 20 pack-years), and heavy smokers (≥ 20 pack-years). The blood flow was intraoperatively equal in RFFFs (84.5 AU vs. 84.5 AU; p  = 0.900) and increased in ALTFs (80.5 AU vs. 56.5 AU; p  = 0.001) and postoperatively increased in RFFFs (114.0 AU vs. 86.0 AU; p  = 0.035) and similar in ALTFs (70.5 AU vs. 71.0 AU; p  = 0.856) in heavy smokers compared to nonsmokers. The flap survival rate was similar in nonsmokers, light smokers, and heavy smokers (97.3%, 98.4%, and 100.0%). Smoking partially increases rather than decreases microvascular free flap perfusion, which may contribute to similar flap survival rates in smokers and nonsmokers.

Unattached surface probes are commonly used with the O2C analysis system (LEA Medizintechnik, Germany) to monitor microvascular free flap perfusion. This study compared attached and unattached surface probes for extraoral free flaps. The study included 34 patients who underwent extraoral microvascular head and neck reconstruction between 2020 and 2022. Flap perfusion was monitored postoperatively using the O2C analysis system at 0, 12, 24, 36, and 48 h, with an attached surface probe at 3 mm tissue depth and an unattached surface probe at 2 mm and 8 mm tissue depths. Clinical complications, technical errors, and perfusion measurement values were compared. No clinical complications (attachment suture infections) or technical errors (probe detachment) occurred. Flap blood flow values of the probes were partially different (3 mm vs. 2 and 8 mm: p < 0.001; p = 0.308) and moderately correlated (3 mm with 2 and 8 mm: r = 0.670, p < 0.001; r = 0.638, p < 0.001). Hemoglobin concentration and oxygen saturation values were generally different (3 mm vs. 2 and 8 mm: all p < 0.001) and variably correlated (3 mm with 2 and 8 mm: r = 0.756, r = 0.645; r = 0.633, r = 0.307; all p < 0.001). Both probes are comparable in terms of technical feasibility and patient safety, with flap perfusion values dependent on tissue measurement depth.

Therapies using dental pulp stem cells (DPSCs) or stem cell-derived extracellular vesicles (EVs) have shown promising applications for bone tissue engineering. This in vitro experiment evaluated the joint osteogenic capability of DPSCs and EVs on alloplastic (maxresorp), allogeneic (maxgraft), and xenogeneic (cerabone) bone grafts. We hypothesize that osteogenic differentiation and the proliferation of human DPSCs vary between bone grafts and are favorable under the influence of EVs. DPSCs were obtained from human wisdom teeth, and EVs derived from DPSCs were isolated from cell culture medium. DPSCs were seeded on alloplastic, allogeneic, and xenogeneic bone graft substitutes for control, and the same scaffolds were administered with EVs in further groups. The cellular uptake of EVs into DPSC cells was assessed by confocal laser scanning microscopy. Cell vitality staining and calcein acetoxymethyl ester staining were used to evaluate cell attachment and proliferation. Cell morphology was determined using scanning electron microscopy, and osteogenic differentiation was explored by alkaline phosphatase and Alizarin red staining. Within the limitations of an in vitro study without pathologies, the results suggest that especially the use of xenogeneic bone graft substitutes with DPSCS and EVs may represent a promising treatment approach for alveolar bone defects.

Autologous vein grafts remain the gold standard for microvascular interpositions in reconstructive maxillofacial surgery, despite their high failure rates and the additional operation site. Against this background, this ex vivo study investigates a novel biohybrid microvascular graft based on elastin-like recombinamers (ELRs). The biohybrid graft design consists of ELRs combined with the mechanical support of textile components. The compliance and pressure resistance of the developed grafts were evaluated and compared with human fresh cadaver vessels (radial artery). The ELRs biohybrid grafts were microsurgically anastomosed with human radial arteries, and were compared with human vein interposition grafts from the saphena vein. The ELRs grafts exhibited comparable and favorable compliance to real human vessels. The burst pressure values of 543 ± 71 mmHg of the ELRs grafts were above the physiological blood pressure load. The tensile strength of the interponated ELRs grafts were significantly higher at 4.2 ± 1.15 N ( p  = 0.025) compared to interponated venous grafts with tensile strength of 3.20 ± 0.65 N. The ex vivo investigations of the novel ELRs biohybrid microvascular grafts revealed promising properties for the application as microvascular interposition graft in terms of compliance, pressure resistance, and tensile strength compared to the current gold standard.

Background Good communication between patients and practitioners is essential, especially during dental procedures, as these treatments are often associated with increased nervousness and anxiety. The aim of this study was to investigate, implement and evaluate a concept for communication skills training by using targeted training in combination with simulation patients in dental education. Methods Students ( n  = 34) were assigned to four small groups receiving targeted training consisting of two parts. A lecture about the theoretical basics of communication skills and two practical sessions with simulation patients. During this training, one of the students performed the conversation with the patient. Immediately after self-assessment was obtained, the simulation patient, the remaining students and the lecturer provided feedback. Additionally, anonymous surveys were administered to the students at the beginning of the semester, immediately after the training and at the end of the course. Results The students rated the learning of communication skills as important for later professional life at all times. After targeted training followed by subsequent use in simulated patients, there was a significant improvement in communication skills ( p  < 0.001). The number of open-ended questions asked to patients after attending the course significantly increased ( p  = 0.0245). The communication training was considered useful, especially in small groups. Conclusion The implementation of targeted training with subsequent use in simulated patients significantly contributed to the students’ improvement in communication skills. The concept offers a good opportunity to better prepare students for interaction with patients, both in their studies and in their upcoming professional lives.

Regeneration of jawbone defects poses major challenges. The combination of dental pulp stem cells (DPSCs) or DPSC-derived extracellular vesicles (EVs) with bone substitute materials shows promising potential for bone tissue engineering in vitro. This study evaluated the in vivo bone regeneration potential of DPSCs and EVs with bone graft substitutes in a novel intrabony defect model. DPSCs were isolated from 35 male Sprague–Dawley rat incisors, and EVs were collected from the cell culture medium. DPSCs were seeded onto alloplastic and xenogeneic bone graft materials and implanted into bone defects. Control groups received bone substitutes without DPSCs or EVs. Micro-computed tomography (µCT) was performed at 12 and 24 weeks post-implantation to assess bone volume (BV), bone density (BD), trabecular thickness (Tr.Th), bone growth rate (BGR), and bone-to-mineral ratio (BMR). Both graft types increased BV and BD, with no significant differences between them. Tr.Th increased across all treatments after 24 weeks, indicating ongoing bone remodeling. Notably, xenogeneic grafts combined with DPSCs and EVs significantly improved BGR (p = 0.034) and BMR (p = 0.021) compared to alloplastic grafts with DPSCs. Xenogeneic bone grafts combined with DPSCs and EVs appear to be a promising approach for bone regeneration of alveolar bone defects.