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The aim of this study was to analyze and compare the accuracy and quality of six 3D printing systems available on the market. Data acquisition was performed with 12 scans of human mandibles using an industrial 3D scanner and saved in STL format. These STL files were printed using six different printing systems. Previously defined distances were measured with a sliding caliper on the 72 printed mandibles. The printed models were then scanned once again. Measurements of volumes and surfaces for the STL files and the printed models were compared. Accuracy and quality were evaluated using industrial software. An analysis of the punctual aberration between the template and the printed model, based on a heat map, was also carried out. Secondary factors, such as costs, production times and expendable materials, were also examined. All printing systems performed well in terms of accuracy and quality for clinical usage. The Formiga P110 and the Form 2 showed the best results for volume, with average aberrations of 0.13 ± 0.23 cm3 and 0.12 ± 0.17 cm3, respectively. Similar results were achieved for the heat map aberration, with values of 0.008 ± 0.11 mm (Formiga P110) and 0.004 ± 0.16 mm (Form 2). Both printers showed no significant difference from the optimal neutral line (Formiga P110, p = 0.15; Form 2, p = 0.60). The cheapest models were produced by the Ultimaker 2+, with an average of 5€ per model, making such desktop printers affordable for rapid prototyping. Meanwhile, advanced printing systems with sterilizable and biocompatible printing materials, such as the Formiga P110 and the Form 2, fulfill the high expectations for maxillofacial surgery.

Oral squamous cell carcinoma (OSCC) arising from the upper oral cavity is rare compared to other localizations. While cervical lymph node metastasis (CLNM) can be predicted to some extent, the probability of occult CLNM remains high. The aim of this study is to determine risk factors affecting clinical decision making.A retrospective analysis of patients surgically treated between 2012 and 2017 for OSCC of the upper oral cavity was performed.A total of 66 patients were included. Of these, 25 patients (37.9%) presented with CLNM after histopathological examination (pN+/cN0: 10/44 (22.7%); pN+/cN+: 15/22 (68.2%)). Lymph vessel infiltration (p = 0.03) and grade of differentiation (p = 0.03) were associated with an increased probability for CLNM. Patients with positive nodal disease at the time of primary surgery showed higher tumor depth of invasion (DOI) than patients without CLNM (mean 10.3 mm ± 6.9 versus mean 6.1 mm ± 4.9; p = 0.02). The optimal DOI cutoff value for the prediction of CLNM was 4.5 mm. The OS was significantly higher in patients with a tumor DOI ≤ 4.5 mm (p = 0.01).Elective neck dissection should be preferably performed for OSCC of the upper oral cavity. For early-stage and clinically node-negative patients, sentinel-lymph node biopsy can be an alternative, especially in patients with a DOI ≤ 4.5 mm. Since this group had no occult CLNM below this DOI cutoff value, watch and wait might be an alternative for selected patients.

Study Design: Retrospective study of all patients presented at our emergency department after an accident while riding an e-scooter between 15 June 2019 and 15 December 2019. Out of this group, we subgrouped all patients with injuries to the head and neck area. Objective: Shared e-scooter systems have recently been introduced in many big cities worldwide and are becoming increasingly popular. This retrospective study aimed to give a detailed overview of clinical data on consequences of e-scooter accidents, with particular attention to the maxillofacial point of view. Methods: We performed a single-center retrospective study of all patients presented at our emergency department after an accident while riding an e-scooter between June 15, 2019 and December 15, 2019. Results: Within the observation period, 43 patients (mean age of 32 years; range: 17-64 years) suffered from an accident while riding an e-scooter. Of these, 25 patients (58%) required maxillofacial treatment whereby 9 patients (36%) suffered a fracture (56% fracture of the mandible; 33% fracture of the nasal bone; 11% fracture of the maxilla). Six patients required maxillofacial surgical treatment. Twelve patients (28%) stated to have been driving under the influence of alcohol at the time of the accident (blood alcohol level between 0.77 g/L and 2.32 g/L). None of the patients used body protection, and only one patient wore a helmet (2%). Conclusions: With the introduction of shared e-scooter systems, health-care facilities are faced with an increasing number of accidents related to the use of e-scooters, suffering from a high percentage of injuries in the maxillofacial region. Facial injuries might be reduced by the mandatory use of a helmet with faceguard. The trauma mechanism, in particular, seems to differ from other common trauma cases and needs to be examined more closely.

Computer-aided microvascular mandible reconstruction is an increasingly common procedure in oral and maxillofacial surgery. The aim of this retrospective single-centre study was to evaluate the rate and specifics of hardware removal after fibula free flap (FFF) fixation with a patient-specific reconstruction plate. The study included patients who underwent hardware removal between April 2017 and October 2019. Statistical analyses were performed regarding the different indications for plate removal (dental implantation versus complication) and the surgical approach (intraoral versus extraoral). Plate removal was performed in 29 of 98 patients (29.6%) after FFF fixation with a patient-specific reconstruction plate. Plate removal was done prior to dental implantation in 58.6% of cases and due to complications in 41.4%. Complications seen between reconstructive surgery and plate removal were less frequent in the dental rehabilitation group (8/17 vs 12/12; P = 0.002). Within this group, 35.3% of plates were removed intraorally, and the majority of partial plate removals were performed in the patients with plate removal for dental rehabilitation (72.7% vs 27.3%). Hospitalization was shorter with an intraoral approach (1.7 days vs 4.0 days, P = 0.052). The removal of patient-specific reconstruction plates prior to dental implantation is often partial and can be performed intraorally. The use of patient-specific miniplates for fixation of FFF might facilitate later dental rehabilitation.

Introduction Treatment decisions for fractures of the orbital floor are based on clinical appearance, ophthalmological examination, and computed tomography (CT) scans. In extensive fractures, decisions are easily made between conservative and surgical treatment. However, objective parameters are rare in inconclusive cases. Materials and methods Our retrospective study included 106 patients with unilateral isolated orbital floor fractures. Correlations between preoperative ophthalmological examinations and specific CT parameters were performed. Results The defect size of the fracture appeared to be significantly associated with the presence of diplopia. CT-morphological parameters and preoperative ophthalmological results showed statistical significance for diplopia and incarceration of inferior rectus muscle (IRM), diplopia and displacement of IRM, decreased mobility and incarceration of IRM, and decreased mobility and displacement of IRM. Discussion Our clinical assessment scheme for CT scans of orbital floor fractures is aimed at facilitating treatment decision making using four CT-based variables. As critical size defects of the orbital floor of ≥2 cm2 are likely to cause clinically significant posterior displacement of the globe, resulting in enophthalmos, the proposed parameters offer a readily accessible and easy to evaluate scheme that helps to identify patients in need of surgical intervention.

Microvascular free flaps are considered to be the gold standard in reconstructive head and neck surgery. However, reduced postoperative transplant perfusion is one of the serious postoperative complications and calls for close and reliable monitoring. Procalcitonin, C-reactive protein, and leukocytes are closely associated with local and systemic inflammatory reactions and might have prognostic capacity concerning tissue necrosis. This study aimed to evaluate perioperative serum levels of these three biomarkers to assess their potential in postoperative flap monitoring. A total of 100 patients with microvascular head and neck reconstructions were included in the study. Perioperative serum levels of parameters were measured and the clinical data were analyzed and correlated. A total of 13% of all flaps developed reduced postoperative perfusion. Analysis of the parameters revealed statistically significant differences in the overall patient collective over time, irrespective of clinically reduced flap perfusion. Co-factors such as sex and history of tobacco and alcohol abuse showed significant differences. The efficacy of the parameters in free flap monitoring has not been verified, although the role of procalcitonin in postoperative monitoring, with special regard to the early detection of infections, is underlined by the present study results.

Orbital exenteration (OE) is considered to be a mutilating surgical procedure reserved for relentlessly progressive neoplastic disorders or extensive facial trauma with unfavourable eye involvement. Malignant tumours, accounting for the majority of ablative orbital surgeries, may be caused by primary orbital tumours or secondarily by neoplasias from the surrounding skin, the maxillary sinus or intracranial malignomas. Orbital exenteration following trauma is mostly caused by penetrating globe defects or extended infections with the danger of intracranial effects. Thoughtful resection planning, the exploitation of reconstructive possibilities as well as the consideration of adjuvant therapy are essential to provide the patient with the best available treatment. As a multitude of reconstructive procedures exist, it is of crucial importance to offer a disease-tailored treatment to achieve a successful patient outcome. After retrospective analysis of 45 orbital exenteration cases within the last decade, we developed a defect-driven classification for ablative orbital therapy followed by a guideline for reconstructive procedures. The classification as well as the reconstruction guideline will help the surgeon to restore anatomic boundaries and to promote physiological and psychological recovery for the patient.

Introduction Neck dissection is an essential component of oral cancer therapy. Based on a standardised approach to cervical lymph node management, we seek to define the relevance of neck dissection extension in cN + cases. Material and methods A retrospective analysis from January 2009 to February 2017 identified 84 patients with oral squamous cell carcinoma with a cN + neck or histologically proven lymph node involvement in intraoperative frozen sectioning and who received modified radical neck dissection according to the presented neck dissection algorithm. Results Overall 11 patients showed lymph node metastasis level IV or V, whereas 19 developed disease recurrence, of which 5 cases were neck recurrences. A total of 30 patients died within the time of observance (overall survival of n = 54). None of those patients with pN + status in levels IV and V reached a 5-year survival. Discussion With a look to the possibility of a 5-year survival in patients with a N+ status in level IV and V, the justification for a radical approach to the neck appears questionable. However, modified radical neck dissection appears to be a suitable for a high-risk oral cancer subgroup. A randomised controlled trial is needed to define guidelines for the neck dissection extent in c/pN + cases.

Bacterial resistance against antibiotics has become an increasing challenge in the treatment of cutaneous infections. Consequences can be severe, especially in infected wounds following previous local radiotherapy. Certain endogenous peptide antibiotics, the host defence peptides (HDPs), exhibit broad-spectrum antimicrobial activity and promote wound healing. Their use as supplements to conventional antibiotics is a current topic of discussion; however, knowledge of their quantities in healthy and compromised tissue is a prerequisite for such discussion. To date, no data concerning HDP quantities in irradiated skin are available.Expression profiles of the genes encoding HDPs, namely human beta-defensin-1 (DEFB1, hBD-1), beta-defensin-2 (DEFB4A, hBD-2), beta-defensin-3 (DEFB103, hBD-3) and S100A7, were assessed in samples of non-irradiated and irradiated neck.A reduction in the expression of all of the examined genes was observed in irradiated skin when compared with non-irradiated skin (statistically significant in the case of S100A7, P = 0.013). Immunohistochemistry revealed differences in HDP distribution with respect to the epithelial layers.The study demonstrates a significant reduction in HDP gene expression in neck skin as a result of radiotherapy. These findings might represent a starting point for novel treatments of cutaneous infections in irradiated patients, such as topical supplementation of synthetic HDP.

Microvascular free flaps are complex but important tools in oral and maxillofacial surgery (OMFS), and though techniques to raise flaps are challenging surgeons often have little structured training. In this study we have evaluated a structured, three-day, hands-on, practical training course on raising flaps. Five human, Thiel-embalmed cadavers were used for training in how to raise the following flaps: radial forearm, anterolateral thigh, lateral arm, fibular, latissimus dorsi, scapular, iliac crest, and rectus abdominis. The total duration of the course was 24 hours over three days. All participants were asked to evaluate the design and conduct of the course, their own learning curve, and general questions about their knowledge of how to raise flaps and microsurgery. There was a significant increase in participants' assessments of how they raised all free flaps, except the lateral arm flap (4.74 (0.68) compared with 2.42 (0.81); p=0.052) before and after the course. The radial forearm flap was thought to be the most relevant in clinical practice (n=40; 75%), followed by the anterolateral thigh (n=5; 9%) and fibular (n=4; 8%) flaps. Comparisons between residents and consultants showed unsurprising differences in experience with microsurgery and self-assessment in raising particular free flaps before the course. We have shown that a structured, hands-on course using a well-established simulation model can significantly improve postgraduate surgeons' skills in raising free flaps.

Objective The limited availability of autogenous oral mucosa in oral and maxillofacial surgery for intraoral grafting after trauma or tumor resection can be balanced by the use of tissue-engineered oral mucosa. However, the use of tissue engineering in autologous grafts is still subject to further research. The aim of this study was to evaluate conditions that lead to a rapid proliferation of vital and highly proliferative oral keratinocytes, which can be used in tissue engineering and consequently help improve surgical management of intraoral mucosal defects. Material and Methods Human oral keratinocytes were obtained from oral mucosal specimens and cultivated. According to their affinity to β1-integrin, epidermal stem cell populations were isolated by using collagen type IV and laminin-coated dishes. Cell proliferation and cell viability were measured by using the CASY cell counter, WST-1 assays, and real-time cell analysis (xCELLigence). Results Measurements on cell proliferation (CASY cell counter) and cell viability (WST-1 assay) showed the characteristic proliferation stages of in vitro–cultivated cells. No statistically significant differences could be monitored (P > .05). Real-time cell analysis, as a more direct and precise technique, revealed a steeper growth curve of adherent cells and therefore generally higher proliferation kinetics compared with cells derived from the supernate. Conclusion Data from real-time cell analysis showed an increased proliferation of adherent cells compared with those derived from the supernate. These results demonstrate the increase of the proliferation capacity by cultivation of keratinocytes derived by adhesion to extracellular matrix proteins.

Surgical treatment of zygomatico-orbital (ZO) fractures is a common procedure in maxillofacial surgery. Often accompanied by pain, trismus and swelling, postoperative morbidity is a major disadvantage, affecting patients' quality of life. The appliance of kinesiologic tape (KT) improves the blood and lymph flow, removing congestions of lymphatic fluid and haemorrhages. The aim of this study was to find out if the application of kinesiologic tape prevents or improves swelling, pain and trismus after zygomatico-orbital fracture surgery, improving patients' postoperative quality of life. A total of 30 patients were assigned for treatment of zygomatico-orbital fractures and were randomly divided into treatment either with or without kinesiologic tape. Tape was applied directly after surgery and maintained for at least 5 days postoperatively. Facial swelling was quantified using a five-line measurement at six specific time points. Pain and degree of mouth opening was measured. Patient's subjective feeling and satisfaction was queried. The results of this study show that application of kinesiologic tape after zygomatico-orbital surgery significantly reduced the incidence of swelling with an earlier swelling maximum, and decreased the maximum turgidity for more than 60% during the first 2 days after surgery. Although, kinesiologic tape has no significant influence on pain control and trismus, mouth opening increased earlier after operation in the kinesiologic tape group compared to the no-kinesiologic tape group. Furthermore, patients with kinesiologic tape felt significantly lower morbidity than those without kinesiologic tape. Therefore kinesiologic tape is a promising, simple, less traumatic, economical approach, which is free from adverse reaction and improves patients' quality of life.

The aim of this study was to evaluate the role of oxidative and nitrosative stress in autogenous bone grafts to the mandible based on immunohistochemical analysis. Material and methods Using a well-established sheep model autogenous bone grafts were harvested form the iliac bone. A combination of a Collagen Membrane (CM) and Deproteinized Bovine Bone Material (DBBM) was used to cover the bone graft (Experiment 2). This modification was compared with simple onlay bone grafts (Experiment 1). Immunohistochemically, the expression of specific stable degradation products of oxidative and nitrosative stress was compared between the two experimental groups. Results Specific markers for oxidative and nitrosative stress showed statistically significant differences in expression in the different experimental groups. The influence of oxidative and nitrosative stress on osteoblasts (OB), osteoclasts (OC), and osteocytes (OCy) was analysed. Experiment 2 showed increased expression of markers in OB and decreased expression in OC. Conclusions Taking the result of this study and reports from the literature into consideration grafts in Experiment 2 showed less resorption and atrophy, higher activity of OB and inhibition of OC, and less expression of Reactive Oxygen and Nitrogen Species (RONS) as markers of oxidative stress within the graft. These data illustrate the improved remodelling processes in grafts using CM and DBBM.

Osteonecrosis of the jaw as a result of treatment with receptor activators of nuclear factor kappa-B ligand (RANKL) inhibitors (denosumab) is a new type of bony necrosis, the exact pathogenesis of which is unknown. Our aim was to find out whether the turnover of bone in the jaw is increased after denosumab has been given compared with other skeletal sites, and if that turnover might have a role in denosumab-related osteonecrosis of the jaw (DRONJ). Bone scintigraphic images of 45 female patients with breast cancer and bone metastases were analysed retrospectively, and divided into 3 groups: those given denosumab, those given a bisphosphonate, and a control group (n=15 in each). All patients had bone scintigraphy before treatment (T0) and during the course of treatment after 12 (T1) and 24 (T2) months. The data were analysed quantitatively using 6 preset bony regions of interest. There was similar turnover of bone in the mandible compared with other skeletal sites (such as the femur), while the maxilla showed significantly higher turnover. None of the bony regions investigated showed any significant changes after the bisphosphonate had been given. There was a tendency to increase bone turnover in those patients taking denosumab. The bone turnover of the jawbone is not overtly changed either by a bisphosphonate or denosumab, so it seems unlikely that oversuppression of bony turnover in the jawbones plays an important part either in the pathogenesis of DRONJ or in the bisphosphonate-related osteonecrosis of the jaw (BRONJ).

Objective Microcirculation and oxygen supply in cervical skin were measured with an optical, noninvasive method in patients with or without radiotherapy before neck dissection. The course of wound healing was monitored after the surgical procedure to identify predictive factors for postoperative wound healing disorders. Study Design Tissue spectrophotometry and laser Doppler flowmetry were used to determine capillary oxygen saturation, hemoglobin concentration, blood flow, and blood velocity at 2-mm and 8-mm depths in the cervical skin of 91 patients before neck dissection in a maxillofacial unit of a university hospital in Munich, Germany. Parameters were evaluated for differences between patients with irradiation (24) and without (67) and patients with wound healing disorders (25) and without (66) (univariate or multivariate statistical analyses). Results Velocity at 2 mm was lower in irradiated skin (P = .016). Flow at 2 mm was higher in patients with wound healing disorders (P = .018). Conclusions High flow values could help to identify patients at risk for cervical wound healing disorders.

Purpose The aim of the present study was to investigate whether the application of elastic therapeutic tape (Kinesio Tape [KT]) prevents or decreases swelling, pain, and trismus after open reduction and internal fixation of mandibular fracture, thus improving patients' postoperative morbidity. Materials and Methods To address the research purpose, the investigators designed and implemented an open-label, monocentric, parallel-group, randomized clinical trial. Patients were prospectively assigned for treatment of unilateral mandibular fractures and randomly allocated to receive treatment with or without KT application. KT was applied directly after surgery and maintained for 5 days postoperatively. Facial swelling was quantified using a 5-line measurement at 6 specific time points. Pain score was assessed using a 10-level visual analog scale; mouth opening was measured. In addition, all patients were asked to evaluate overall satisfaction and swelling (2 groups) and the effect of the tape on movement and comfort (KT group only). Results The study included 26 patients (11 female and 15 male; mean age, 43 yr; standard deviation, 18.5 yr). Application of KT after surgery for mandibular fracture had a statistically significant influence on tissue reaction and swelling, decreasing the incidence of swelling and turgidity by more than 60% during the first 2 days after surgery. Although KT had no significant influence on pain control, patients in the KT group perceived significantly lower morbidity. Conclusion The present results showed that KT after open reduction and internal fixation of mandibular fracture is a promising, simple, less traumatic, and economical approach for managing postoperative swelling that is free from systemic adverse reactions, thus improving patients' quality of life.

Introduction Tumour aftercare (tac) is an essential tool in oncology. The main aim of these follow ups is to diagnose recurrence and second tumours from the beginning. Tac appointments can create a special environment for patients' further concerns. The purpose of the current study was to evaluate tac of patients diagnosed with OSCC and to investigate their health related quality of life (hrql). Material and methods A German questionnaire was created by two maxillo-facial surgeons with several years of tac experience. It was handed out to 100 German-speaking OSCC patients during tac. Results were statistically evaluated with SPSS (SPSS version 21.0; SPSS, IBM; Chicago, IL, USA). The inclusion criterion was that diagnosis and surgery were performed at our department and that the patients attended our tac regularly. Results Side effects such as difficulties in speaking and swallowing were evaluated as being significantly higher in cases who were administered adjuvant radiochemotherapy (art) compared with the surgical therapy group (stg) (p = 0.03). Anxiety occurred in 80% of all female patients (p = 0.02), 90% of them with a high psychological strain because of the cancer diagnosis (p = 0.04). Discussion To date, tac is a rare topic in literature. Moreover, only a few trials have focused on hrql in OSCC. A main result of the current study is that during tac, OSCC patients should be regularly questioned about their symptoms and mental state. Further, the need of the majority of OSCC patients for coping therapies can concomitantly be evaluated. Conclusion The evaluation of tac is of high relevance. The results of the current study have encouraged us to establish this questionnaire as a routine tool in our tac.

Introduction A supraomohyoid neck dissection (SOHND) is part of the surgical management of patients with oral cancer, even in the absence of clinical or radiographic evidence of neck disease. We have investigated a standardized approach to the management of cervical lymph nodes, in patients with a primary oral cancer. A modified surgical technique has been presented and a clinical algorithm has been described and evaluated. Materials and methods SOHND was performed either uni- or bi-laterally. In cases of positive nodes in levels II or III, the dissection was extended in terms of a modified radical neck dissection (MRND) and a SOHND was performed contralaterally. Results 112 patients were included. 42% had lymph node metastases in any level. Overall, lymph node metastases were found in 2.8% of all examined nodes. Most metastases (34.6%) occurred in level Ib. 12.6% were located in level IIb. No metastases could be detected in levels IV and V. No statistically significant difference could be shown with regard to T-stage, location, or co-factors as gender and age. Discussion SOHND is the gold-standard in patients with no preoperative evidence of lymph node metastases. The presented algorithm is able to facilitate dissection and histological analysis and might improve the surgical care in current treatment concepts. The extension to an MRND facilitates the identification of patients in need of adjuvant therapy.

Oral squamous cell carcinomas, and tongue malignancies in particular, are among the most common tumors of the oral cavity. Classification for therapeutic and prognostic purposes is routinely made using the tumor, node, metastasis (TNM) system; however, current definitions do not include tumor thickness. We therefore aimed to identify variables associated with survival, and to evaluate the correlation between tumor thickness and the occurrence of lymph node metastasis.All patients undergoing radical tumor resection for squamous cell carcinomas of the tongue between 2000 and 2012 were included. Specimens were analyzed histopathologically and co-variables were interpreted. Follow-up was performed clinically and radiologically for at least 3years according to current guidelines.We included 492 patients who had a median follow-up of 70months. Variables associated with survival (p

Surgical treatment of bisphosphonate-related osteonecrosis of the jaws (BRONJ) combines excision of adequate damaged bone and watertight coverage by appropriate vascularized tissue. Local tissues are preferred when possible. This study compares local mucoperiosteal flaps with mylohyoid flaps with special emphasis on their influence on wound healing.A total of 195 patients with BRONJ in the mandible were included in this prospective study. The control group (n = 169) were treated with a mucoperiosteal flap, whereas patients of the study group (n = 26) received a mylohyoid flap.Recurrence of BRONJ was significantly reduced (p = 0.023) as was extent of necrosis (p = 0.001) in patients with mylohyoid flaps.This study demonstrates the importance of a sufficient mucosal coverage in surgical treatment of BRONJ. The mylohyoid flap provides an additional tissue coverage, which seems to account for the significantly reduced rate of disease recurrence.The vascularized mylohyoid flap is an important tool in the complex and challenging surgical care of BRONJ.

Bisphosphonate related osteonecrosis of the jaws (BRONJ) is a recognised unwanted effect of these drugs which affect bone remodelling. Treatment options range from conservative approaches through local bone debridement to free flap reconstruction following segmental resection. This current study aims to evaluate clinical outcomes after microvascular tissue transfer in BRONJ patients.A total of 212 BRONJ patients were included in this prospective investigation. Those who met defined inclusion criteria and received a surgical intervention were reviewed regularly during a follow-up period of at least 6 months.Twenty-five patients (11.8%) received free flap reconstructions. A mean of 2.12 local debridements were performed before microvascular tissue transfer. A mean of 29.25% showed BRONJ recurrence after minimalist surgical intervention, compared to significantly less in patients after resection and free flap reconstruction. The postoperative fistula rate was significantly higher in patients, who received mucoperiosteal flaps.This study underlines the importance and effectiveness radical resection and free flap reconstruction in the complex and challenging surgical treatment of BRONJ patients in a large patient cohort study. Nevertheless, all patients received radical intervention after failure of minimally invasive treatment. An individualized analysis and planning is necessary to identify appropriate patients for free flap reconstructions.

Interest in a surgical career is declining among medical students, and many more need to commit themselves to becoming surgeons to cope with this. We have therefore developed a one-day practical lesson in surgical skills to find out whether a short course such as this can make students more enthusiastic about surgery, and about subsequently pursuing a career in one of its subspecialties. Fifty-four randomly-selected medical students did a one-day practical course in the skills required for maxillofacial surgical specialties. The 4 subdivisions involved - traumatology, resection of a tumour (cancer surgery), plastic surgery (microsurgery), and cleft lip and palate surgery. All students took written tests and completed an evaluation form about their interest in a surgical career before and after training. There was a significant increase in test scores in almost all categories at the end of the course, and significantly more students were prepared to consider a surgical career or a career in maxillofacial surgery after the training. This study shows that a one-day training course in surgical skills can significantly improve medical students' surgical knowledge, and might encourage them to enter a surgical career. We recommend the integration of a short training course such as this into the medical school curriculum. Only time and further evaluation will tell whether this increased exposure to surgical techniques can be transformed into additional surgeons.

The purpose of this study was to determine the clinical and biomechanical outcome of two different titanium mini-implant systems activated with different load regimens. A total of 200 mini-implants (102 Abso Anchor and 98 Dual Top) were placed in the mandible of eight Gottinger minipigs. Two implants each were immediately loaded in opposite direction by various forces (100, 300 or 500 cN) through tension coils. Additionally, three different distances between the neck of the implant and the bone rim (1, 2 and 3 mm) were used. The different load protocols were chosen to evaluate the load-related implant performance. The load was provided by superelastic tension coils, which are known to develop a virtually constant force. Non-loaded implants were used as a reference. Following an experimental loading period of 22 and 70 days half of the minipigs were sacrificed, and implant containing bone specimens evaluated for clinical performance and implant stability. Implant loosing was found to be statistically dependent on the tip moment (TM) at the bone rim. Clinical implant loosing were only present when load exceeded 900 cN mm. No movement of implants through the bone was found in the experimental groups, for any applied loads. Over the two experimental periods the non-loaded implants of one type of implant had a higher stability than those of the loaded implants. Dual Top implants revealed a slightly higher removal torque compared with Abso Anchor implants. Based on the results of this study, immediate loading of mini-implants can be performed without loss of stability when the load-related biomechanics do not exceed an upper limit of TM at the bone rim.

We measured the motivation and interest of medical students in oral and maxillofacial surgery at a German university. After a detailed cost-benefit analysis of a course that used an ex-vivo animal model and active participation in the operating theatre, we measured changes in the students' interest in taking up a surgical specialty in the future. We found that practical experience could lower the expenses of the course by almost 70%. Twenty per cent of students chose oral and maxillofacial surgery as an elective in their final year. These students could be residents one day.

BACKGROUND: Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a known side effect of the therapy with bisphosphonates. No specific pathologic aspects or histological features are included in the most current definition. This study investigates characteristics of BRONJ with a special emphasis on histomorphologic aspects, evaluating the role of Actinomyces spp. as well as other disease-promoting factors in a formal pathogenetic context. METHODS: We investigated 23 patients (14 female, nine male; mean age: 66 11.8 years) who received bisphosphonates with a gender- /age-matched control group. Tissue specimens were treated according to local standards and analyzed histologically. RESULTS: In 18 (78.3%) BRONJ cases, we found Actinomyces spp. colonies. Bone remodeling could be found in three specimens (13%). Eight specimens (34.8%) showed signs of epithelial proliferation. Analysis of dental treatment before the onset of BRONJ did not reveal significant differences (P > 0.20). In 10 patients (83%; P > 0.05) of the reported cases a relationship between dental treatment and the occurrence of a purulent bone necrosis could be observed. Statistically significant differences in thickness of trabeculae were detected between the two study groups (P = 0.04). CONCLUSIONS: This study demonstrates the important influence of the osteoblast–osteoclast balance in a histomorphologic analysis. Together with cofactors, which are able to trigger the onset of BRONJ, a new pathogenesis model was developed.