Biodegradable magnesium barrier membrane used for guided bone regeneration in dental surgery.

Barrier membranes are commonly used as part of the dental surgical technique guided bone regeneration (GBR) and are often made of resorbable collagen or non-resorbable materials such as PTFE. While collagen membranes do not provide sufficient mechanical protection of the covered bone defect, titanium reinforced membranes and non-resorbable membranes need to be removed in a second surgery. Thus, biodegradable GBR membranes made of pure magnesium might be an alternative. In this study a biodegradable pure magnesium (99.95%) membrane has been proven to have all of the necessary requirements for an optimal regenerative outcome from both a mechanical and biological perspective. After implantation, the magnesium membrane separates the regenerating bone from the overlying, faster proliferating soft tissue. During the initial healing period, the membrane maintained a barrier function and space provision, whilst retaining the positioning of the bone graft material within the defect space. As the magnesium metal corroded, it formed a salty corrosion layer and local gas cavities, both of which extended the functional lifespan of the membrane barrier capabilities. During the resorption of the magnesium metal and magnesium salts, it was observed that the membrane became surrounded and then replaced by new bone. After the membrane had completely resorbed, only healthy tissue remained. The in vivo performance study demonstrated that the magnesium membrane has a comparable healing response and tissue regeneration to that of a resorbable collagen membrane. Overall, the magnesium membrane demonstrated all of the ideal qualities for a barrier membrane used in GBR treatment.

Biodegradable magnesium fixation screw for barrier membranes used in guided bone regeneration.

An ideal fixation system for guided bone (GBR) regeneration in oral surgery must fulfil several criteria that includes the provision of adequate mechanical fixation, complete resorption when no longer needed, complete replacement by bone, as well as be biocompatible and have a good clinical manageability. For the first time, a biodegradable magnesium fixation screw made of the magnesium alloy WZM211 with a MgF2 coating has been designed and tested to fulfill these criteria. Adequate mechanical fixation was shown for the magnesium fixation screw in several benchtop tests that directly compared the magnesium fixation screw with an equivalent polymeric resorbable device. Results demonstrated slightly superior mechanical properties of the magnesium device in comparison to the polymeric device even after 4 weeks of degradation. Biocompatibility of the magnesium fixation screw was demonstrated in several in vitro and in vivo tests. Degradation of the magnesium screw was investigated in in vitro and in vivo tests, where it was found that the screw is resorbed slowly and completely after 52 weeks, providing adequate fixation in the early critical healing phase. Overall, the magnesium fixation screw demonstrates all of the key properties required for an ideal fixation screw of membranes used in guided bone regeneration (GBR) surgeries.

Critical-size Defect Augmentation Using Sintered and Non-Sintered Bovine Bone Matrix - An Experimental Controlled Study in Minipigs.

PURPOSE: Xenogeneic bone substitute materials are often used for augmentation of larger bone defects. Purification methods for these materials vary, mainly in terms of temperature. The aim of this study was to determine in vivo how sintering affects quantitative and qualitative bone regeneration of 2 bovine augmentation materials. METHODS: A total of 56 critical size defects were set at the frontal bone of 14 domestic pigs (4 each) and filled randomly with either bovine, sintered hydroxyapatite (BO), bovine, non-sintered hydroxyapatite (BOS), local autologous bone (AB) or left empty. All defects were additionally covered with a collagen membrane. Specimens were harvested after 4 and 8 weeks and were evaluated histologically and histomorphometrically. RESULTS: Histologically new bone could be seen in every group. Significantly highest new bone formation was found in AB. No significant difference could be detected between BO and BOS. CONCLUSIONS: According to the results of this study, sintered bone substitute material remains histologically distinguishable but does not affect quantitative and qualitative bone regeneration.

Osteotomy speed, heat development, and bone structure influence by various piezoelectric systems-an in vitro study.

OBJECTIVES: The aim of this in vitro study was to evaluate osteotomy speed, heat development, and bone structure influence from osteotomies performed by various piezoelectric devices and insert tips. These devices and tips were compared among each other with regard to conventional rotatory and oscillating systems with special focus on the insert tip design and thickness. MATERIAL AND METHODS: The osteotomies were conducted on porcine ribs utilizing 12 different insert tips (straight and angulated) and three conventional systems. After time and temperature measurements, histological analysis was carried out. Light microscopy was used to evaluate the roughness of the osteotomic surface and to search for indications of thermal bone necrosis. A special software analyzing tool was employed to determine cutting width (mm) and debris (%). RESULTS: All piezoelectric tips created smooth cuts. Cutting widths in general were wider than the actual insert tip size with a tendency for narrow straight insert tips producing relatively wide osteotomies, whereas narrow angulated inserts produced relatively small osteotomies. None of the samples demonstrated distinct indication of necrosis. Overall, there was only a small amount of debris in all osteotomy gaps. Conventional rotatory saws were faster and created less heat compared to all tested piezoelectric systems. Straight tips proved faster osteotomy speed than angulated tips. Thin insert tips indicated to have a positive correlation to osteotomy time and performed faster than conventional microsaw. The average temperature rise was lower when using conventional systems, but critical exceeding temperatures were only observed in short-time exceptional cases. In general, temperature rise was less when using angulated inserts. CONCLUSION: All tested tips are appropriate for bone surgery. Only small differences were found among the piezoelectric insert tips. Although conventional rotatory systems in general performed faster osteotomies, special designed and thin piezoelectric insert tips seem to have a positive influence on osteotomy speed. Ultimately, none of the tested devices or inserts combined all best features of speed, heat development, bone structure influence, and safety. CLINICAL RELEVANCE: Narrow and straight piezoelectric insert tips demonstrated reduced osteotomy times. Nevertheless, a combination of conventional and piezoelectric systems in clinical practice might be the best way to work time-efficient, patient-oriented, and safe. The choice of instrument should be based on clinical experience of the user and should be evaluated individually depending on the case.

Current concepts in cleft care: A multicenter analysis.

The current surgical techniques used in cleft repair are well established, but different centers use different approaches. To determine the best treatment for patients, a multi-center comparative study is required. In this study, we surveyed all craniofacial departments registered with the German Society of Maxillofacial Surgery to determine which cleft repair techniques are currently in use. Our findings revealed much variation in cleft repair between different centers. Although most centers did use a two-stage approach, the operative techniques and timing of lip and palate closure were different in every center. This shows that a retrospective comparative analysis of patient outcome between the participating centers is not possible and illustrates the need for prospective comparative studies to establish the optimal technique for reconstructive cleft surgery.

Odontogenic sinusitis maxillaris: A retrospective study of 121 cases with surgical intervention.

PURPOSE: Otolaryngologists, dentists and maxilla-facial surgeons see patients suffering from odontogenic maxillary sinusitis on a daily routine. The study was performed to investigate the different origins of the odontogenic maxillary sinusitis ranging from periodontitis to augmentative implant surgery. Furthermore, the microbial flora of purulent odontogenic maxillary sinusitis was analyzed in order to present a proper antibiotic treatment in addition to a surgical approach. MATERIALS AND METHODS: A retrospective study was performed, analyzing the clinical trials of 121 patients suffering from odontogenic maxillary sinusitis who undergone surgery. Harvested bacteria were tested for susceptibility on a routine base, surgical reports of removed foreign material or dental focus were reviewed as well as preoperative CBCT. RESULTS: Patients mean age was 56.62 (±16 SD) with a slight female gender dominance. Allergic profile to ß-lactam antibiotics had no influence on patients' length of in-hospital stay. 69 out of 121 cases of OMS occurred after dental surgery (extractions, augmentation or implant surgery). Maxillary molars were the teeth mostly hold accountable for an onset without surgery in recent history. 22.3% of the patients possessed a dislocated foreign body in the maxillary sinus. Pseudomonas aeruginosa infection was significantly associated with misplaced foreign bodies (root filling, augmentative dental material e.g. p < 0.05). We protocoled an anaerobic dominance with 45 anaerobes versus 19 aerobes. Ampicillin/Sulbactam (80%) and Piperacillin/Tazobactam (93.3%) present sufficient susceptibly rates to the harvested bacteria. Likewise showed Moxifloxacin (86.3%) equal results, whereas Clindamycin had a poor outcome with merely 50% of the tested bacteria being susceptible to Clindamycin. CONCLUSION: If OMS is diagnosed dental focus should be treated, misplaced bodies should be removed and purulent exacerbation has to be additionally treated with a calculated antibiotic therapy according to the pathogens resistance patterns.

Therapy of sinonasal malignancies invading the orbit-orbital exenteration versus preservation of the orbit plus radiotherapy.

INTRODUCTION: Orbital invasion is a strong independent prognostic factor for sinonasal malignancies. While there is consent about preservation of the orbit for tumors limited to the orbital periosteum there is controversy about the optimal management of sinonasal malignancies transgressing this barrier. Therefore the aim of our study was to compare exenteration versus preservation of the orbit. MATERIAL AND METHODS: 52 patients with sinonasal malignancies invading the orbit beyond the orbital periosteum with involvement of the orbital soft tissues were included in the retrospective study. Prognostic factors were identified through univariate analysis. RESULTS: Univariate analysis revealed a significant impact of N-classification (p = 0.017), and treatment strategy (p = 0.016). Exenteration of the orbit was associated with a significantly better 5-year overall survival rate (65.5%) than preservation of the orbit (14%). CONCLUSIONS: For patients with invasion of the structures beyond the orbital periosteum, exenteration yields better survival results than preservation of the orbital structures in combination with radiotherapy. In cases where both eyes are affected from the tumor or if only one dysfunctional eye would be left over after therapy, we do not recommend orbital exenteration because life quality would be critically deteriorated.

Influence of the volume of soft tissue herniation on clinical symptoms of patients with orbital floor fractures.

INTRODUCTION: One of the most important complications of orbital floor fractures is diplopia and restricted ocular movement. The role of the volume of soft tissue herniation on these clinical symptoms after orbital floor fractures is unclear and potentially may predict development of persistent clinical symptoms. Therefore the aim of this study was to assess pre- and postoperative complications associated to the volume of soft tissue herniation, with special interest to diplopia and bulbus motility impairment. MATERIAL AND METHODS: 204 untreated patients with orbital floor fractures from 2009 to 2011 were included in this retrospective study. Contingency tables and χ2-test were performed to analyze associations between two qualitative variables. p-Values p < 0.05 were considered as significant. Volume measurement was performed in a semiautomatic segmentation method with the software "ITK-Snap". RESULTS: The volume of soft tissue herniation correlated significantly with pre- and postoperative diplopia (p = 0.003; p = 0.002), persistent diplopia (p = 0.009) as well as pre- and postoperative bulbus motility impairment (both p < 0.001). Furthermore we found out significant associations between the volume of soft tissue herniation and pre- and postoperative complications depending on fracture type and reconstruction technique. CONCLUSIONS: Volume measurement of soft tissue herniation may help to predict postoperative complications, particularly bulbus motility restriction and persistent diplopia. The risk for these symptoms rises with increasing volume of soft tissue herniation after orbital floor fractures. Therefore we recommend for these patients within indication an early repair and/or closer observation.

Clinical and histopathological staging in oral squamous cell carcinoma - Comparison of the prognostic significance.

BACKGROUND: In oral cancer the prognostic significance of clinical staging (cTNM) is regarded inferior to histopathologic staging (pTNM) after surgery. This is mainly due to the point that the quality of the cTNM strongly depends on the clinical and radiological examination techniques applied and the physician's experience. The aim of this study was to evaluate the prognostic quality of cTNM and pTNM in a single center cohort. METHODS: This retrospective study included 392 patients with treatment-naive oral squamous cell carcinoma (OSCC). All patients received primary surgery including a neck dissection. According to tumor stage and histopathologic risk factors patients received adjuvant radiotherapy (RT) or radiochemotherapy (RCT). Prognostic factors were identified in univariate analysis by using the log rank test and in multivariate analysis through Cox regression. RESULTS: Clinical and histopathologic staging showed concordance in 62% for the primary tumor and 59% for cN- and pN-classification. In 58% of the cases of discordance the primary tumor was overstaged. In case of discordance of metastatic spread to the cervical lymph nodes, lymph node involvement showed overstaging in 78%. In univariate analysis cT-, cN-, cT- and pT-classification had a significant impact (p<0.05) on overall survival (OS). In multivariate analysis only pT- and pN-classification had a significant impact on OS. CONCLUSION: Despite advances and modern radiologic techniques, pTNM has a higher prognostic quality than cTNM. Discordance between clinical and histopathologic staging was observed in up to 40%. When discordance was observed overstaging for clinical T-stage and clinical N-stage was more likely than understaging.

Empiric systemic antibiotics for hospitalized patients with severe odontogenic infections.

INTRODUCTION: Odontogenic infections may lead to severe head and neck infections with potentially great health risk. Age, location of purulent affected sites and beta-lactam allergy are some mentionable factors regarding patients' in-hospital stay and course of disease. Are there new challenges regarding bacteria' antibiotic resistance for empiric treatment and what influences do they have on patients' clinical course? METHODS: We analyzed in a 4-year retrospective study the medical records of 294 in-hospital patients with severe odontogenic infections. On a routine base bacteria were identified and susceptibility testing was performed. Length of stay in-hospital was evaluated regarding patients' age, beta-lactam allergy profile, affected sites and bacteria susceptibility to empiric antibiotics. RESULTS: Length of stay in-hospital was detected to be associated with affected space and penicillin allergy as well (p < 0.05). Isolates presented large amounts of aerobic gram-positive bacteria (64.2%), followed by facultative anaerobic bacteria (gram+/15.8%, gram-/12.7%). Tested ampicillin in combination with sulbactam (or without) and cephalosporins displayed high susceptibility rates, revealing distinguished results regarding clindamycin (p < 0.05). Co-trimoxazol and moxifloxacin showed high overall susceptibility rates (MOX: 94.7%, COTRIM: 92.6%). DISCUSSION: This study demonstrates ampicillin/sulbactam in addition to surgical intervention is a good standard in treatment of severe odontogenic neck infections. Cephalosporins seem to be a considerable option as well. If beta-lactam allergy is diagnosed co-trimoxazol and moxifloxacin represent relevant alternatives. CONCLUSION: Age, allergic profile and bacteria' resistance patterns for empiric antibiotics have an influence on patients in-hospital stay. Ampicillin/sulbactam proves itself to be good for empiric antibiosis in severe odontogenic infections. Furthermore cephalosporins could be considered as another option in treatment. However moxifloxacin and co-trimoxazol deserves further investigation as empiric antibiosis in odontogenic infections if beta-lactam allergy is diagnosed.

Prevention of post-operative bleeding in hemostatic compromised patients using native porcine collagen fleeces-retrospective study of a consecutive case series.

INTRODUCTION: Various anticoagulant therapy regimes bear the risk of postsurgical bleeding events after dental extractions. Local hemostyptic measures, e.g., collagen fleeces, are applied by surgeons to prevent such bleedings. No standard protocol in prevention of bleeding events has met general acceptance among surgeons yet. PURPOSE: The purpose of this retrospective study was to determine if post-operative bleeding can be prevented by suturing native collagen fleeces into extraction wounds immediately after teeth removal, regardless what anticoagulant regime is performed. METHODS: A total of 741 extraction units were removed from 200 consecutive in-ward patients with or without alternation of different anticoagulant therapy regimes. Anti-vitamin K agents were the most prescribed drugs (n = 104, 52 %), followed by Acetylsalicylate (ASS) (n = 78, 39 %). Nineteen (9.5 %) patients received a dual anti-platelet therapy. Out of 104 patients receiving an anti-vitamin K agent (phenprocoumon), 84 patients were bridged, 20 patients continued to their anticoagulant therapy without alterations. Following careful tooth extraction, extraction sockets were filled using a native type I and III porcine collagen sponge (Collacone, Botiss Biomaterials, Berlin), supported by single and mattress sutures for local hemostasis. Post-operative bleeding events were rated according to their clinical relevance. RESULTS: In the post-operative phase, 8 out of 200 consecutively treated patients experienced a post-operative bleeding event. All of them had been designated for a long-term anti-vitamin K therapy (p ≤ 0.05), and extractions were performed under a heparin bridging regime (n = 6) or an uninterrupted anti-vitamin K agent therapy (n = 2). No bleeding events occurred in patients with ASS 100 therapy or low-dose LMWH therapy (p ≤ 0.05), or in patients with dual anti-platelet therapy (0 out of 24). None of the bleeding events put patients' health at risk or required systemic intervention. CONCLUSION: Sufficiently performed local hemostyptic measures, like the application of collagen fleeces in combination with atraumatic surgery, bears a great potential for preventing heavy bleeding events in hemostatic compromised patients, regardless of their anticoagulant therapy.

Changes in volume during the four months' remodelling period of iliac crest grafts in reconstruction of the alveolar ridge.

Our aim was to assess the four months' resorption rates of onlay iliac crest grafts in atrophic jaws prospectively, and to identify factors that influence them. Twenty-four patients had reconstructions of the alveolar ridge with iliac crest onlay grafts at 30 sites on the mandibles and maxillas. The augmentation volumes were measured on cone-beam computed tomographic (CT) data-sets directly after augmentation (V1), and after four months' remodelling (V2). Statistical analysis allowed identification of potential influences from the recipient sites, volume of the graft, and the patients' smoking behaviour. The mean (range) initial onlay graft volume (V1) was 2.82 (0.66 to 6.41) ml. After four months, the mean measured onlay graft volume (V2) was 2.39 (0.47 to 6.21) ml. Mean iliac crest onlay graft volume resorption after four months of remodelling was 0.43 (-0.15 - 1.78) ml (15%). We found no significant differences in the resorption rates of iliac crest onlay grafts between different recipient sites (maxilla and mandible) or in dependence on the volume of iliac crest grafts. Smokers tended to have a higher rate of resorption, but not significantly so (p=0.056). The results of this study indicate the most favourable resorption rates for iliac crest onlay grafts that we know have seen published to date.

Moving the mandible in orthognathic surgery - A multicenter analysis.

Orthognathic surgery has always been a classical focus of maxillofacial surgery. Since more than 100 years, various surgical techniques for mandibular repositioning have been developed and clinically tested. Since the establishment of plate and screw osteosynthesis, orthognathic surgery became more stable and safe. Nowadays, different surgical methods for mobilising the mandible are existing. This international multicenter analysis (n = 51 hospitals) is providing first evidence based data for the current use of different surgical methods. The dominating techniques were Obwegeser/dal Pont (61%) followed by Hunsuck/Epker (37%) and Perthes/Schlössmann (29%). The main osteosynthesis materials were plates (82%), bicortical screws (23.5%), or a combination of both (5.9%). 47% of all centers reported to use several surgical methods at the same time, depending on the anatomical problem and the surgeon's preference. This shows that different surgical methods seem to work as comparable, safe, and reliable procedures in everydays clinical practise. On this basis, further prospective studies could evaluate possible advantages for our patients.

Differences in crestal bone-to-implant contact following an under-drilling compared to an over-drilling protocol. A study in the rabbit tibia.

OBJECTIVES: The objective of this study is to compare bone-to-implant contact (BIC) between implants inserted at high torque due to under-drilling of the crestal bone to those inserted at low torque due to over-drilling of the crestal bone. MATERIALS AND METHODS: Forty implants with diameters of 3.75 mm (group A) or 3.55 mm (group B) were inserted in the proximal tibiae of NZW rabbits in two separate surgeries on day 0 or 21. Osteotomy of the crestal bone was finalized with a 3.65-mm drill. In group A, implants were inserted at torque ≥35 Ncm (under-drilling) and in group B with torque <10 Ncm (over-drilling). Implants and their surrounding bone were retrieved on day 42, thus creating 3- and 6-week observation periods, processed for non-decalcified histology and stained with toluidine blue. Crestal BIC (c-BIC) and total BIC (t-BIC) were measured. Wilcoxon test was used to evaluate differences between groups. RESULTS: Three weeks post-surgery, the mean c-BIC in group A was 16.3 ± 3.3 vs 31.5 ± 3.4 % in group B (P < 0.05). At 6 weeks, a similar trend was observed (group A: 28.7 ± 3.6 %; group B: 38.4 ± 4.9 %) (P > 0.05). No differences in t-BIC were noted at 3 weeks and at 6 weeks between the groups. CONCLUSIONS: Insertion of implants with an over-drilling protocol of the crestal aspect of the osteotomy resulted in increased short-term crestal bone-to-implant contact. CLINICAL RELEVANCE: Insertion of implants with a high torque following an under-drilling protocol, commonly used for immediate loading, may reduce crestal bone-to-implant contact at early healing stages.

The importance of early diagnosis in patients with maxillary sinus carcinoma.

There are two major challenges in the early diagnosis of maxillary sinus carcinoma: the maxillary sinus is not susceptible to direct inspection and palpation, and symptoms are uncharacteristic. The aim of this study was to assess the impact of the time interval between first symptoms noticed by the patient and the detection of the tumor on survival. 88 patients with maxillary sinus tumors were included in the retrospective study. Prognostic factors were identified through univariate analysis. Univariate analysis (p = 0.019) revealed a significant impact of the time interval from first symptom to diagnosis on overall survival. With increasing duration of the symptoms 5-year overall survival was reduced from 65 % for duration between 0 and 2 months to 24 % for duration of symptoms longer than 12 months. Furthermore, we found a significant association (p = 0.033) between local extension of the tumor and time interval from first symptom to diagnosis. Early diagnosis is often difficult because of uncharacteristic symptoms, which are identical with benign diseases of the maxillary sinus. The delay between the occurrence of the first symptom and diagnosis often makes a curative treatment impossible.

Autofluorescence imaging in recurrent oral squamous cell carcinoma.

The survival of patients with oral cancer is decreased by locoregional recurrence after an initial multimodal treatment. In order to identify lesions in the oral cavity for a possible recurrence, clinical evaluation as well as MRI or CT scanning is advised. The evaluation of mucosa lesions is hampered by changes related to radio- and chemotherapy as well as reconstruction with tissue flaps. Several techniques for easier identification of tissue abnormalities in the oral cavity have been advocated as adjuncts in order to facilitate identification. Especially methods using altered tissue fluorescence have gained much interest during the last decade. The aim of our prospective study was to evaluate fluorescence properties of undiagnosed mucosa lesions with the VELscope device in patients with multimodal treated oral cancer prior to histological confirmation. In total, 41 patients with a history of oral squamous cell carcinomas (OSCC) (19 females and 22 males) with undiagnosed mucosa lesions where included in the study. After clinical evaluation, examination and documentation using the VELscope® device were performed. Then, an incisional biopsy was performed. An autofluorescence loss indicating a malignant or dysplastic mucosa condition could be detected in six patients (14.6 %); however, only one OSCC and one SIN revealed a complete autofluorescence loss. In four patients, OSCC was present in lesions with retained autofluorescence. Sensitivity and specificity for the VELscope® examination to identify malignant oral lesions by autofluorescence were 33.3 and 88.6 %, respectively. The positive and negative predictive values were 33.3 and 88.6 %, respectively. No statistical correlation between gender and lesion appearance versus autofluorescence loss could be detected. In contrast to mucosa lesions in patients with no prior treatment, the autofluorescence evaluation with the VELscope reveals no additional information in our analysis. Accordingly, invasive biopsies as gold standard are still needed to get sufficient evidence regarding potential malignancy in patients after multimodal treatment for oral cancer.

Expression of ezrin in oral squamous cell carcinoma: Prognostic impact and clinicopathological correlations.

INTRODUCTION: There have been few investigations into the effects of ezrin expression in oral squamous cell carcinoma (OSCC). The aim of this study was to analyze the influence of ezrin expression on the prognosis of patients with OSCC. MATERIALS AND METHODS: Eighty patients were included in the retrospective study. Expression and localization of ezrin were evaluated using immunohistochemistry. Associations were identified using χ² tests. Prognostic factors were identified by univariate and multivariate analysis. RESULTS: Seventy-six (95%) patients showed ezrin expression. Ezrin expression had a significant impact on overall survival (OS) (p < 0.001). With increasing expression, the 5-year OS rate dropped from 100% for ezrin-negative patients to 47% for patients with high expression. Multivariate analysis confirmed the significant influence of ezrin expression on OS (p = 0.011). Cytoplasmic localization of ezrin led to a significantly lower survival rate in comparison with membranous expression. CONCLUSIONS: Ezrin may serve as a biomarker that predicts biologically aggressive behavior of OSCC and hence improves therapeutic techniques and the prognosis of patients affected with the disease.

The current state of facial prosthetics ­ A multicenter analysis.

Even though modern surgical techniques are dominating reconstructive facial procedures, the capability to use facial epitheses for reconstruction is still an important skill for the maxillofacial surgeon. We present an international multicenter analysis to clarify which techniques are used to fixate facial prostheses. We contacted all maxillofacial departments in Germany, Austria, Switzerland and Norway which were registered with the German society for oral and maxillofacial surgery (DGMKG). These centers were asked via electronical mail to provide information on the type of epithesis fixation systems currently in use. The return rate from 58 departments was 43.1% (n = 25). Overall, implant fixation was the preferred fixation system (92%). Plates were the second most common fixation technique (32%). No centers reported the standard use of non-invasive fixation techniques for permanent epithesis fixation. The main retention systems in use were magnets (24/25), other retention systems are used much less often. The current preferred fixation technique for facial epitheses consists of implant-based, magnet-fixated epitheses. For nasal prostheses, a plate-based, magnet-fixated system is often used.

Prognostic quality of the Union Internationale Contre le Cancer/American Joint Committee on Cancer TNM classification, 7th edition, for cancer of the maxillary sinus.

BACKGROUND: Carcinomas of the maxillary sinus are classified according to the Union Internationale Contre le Cancer (UICC)/American Joint Committee on Cancer (AJCC) TNM classification. The purpose of this study was to assess the prognostic significance of the UICC/AJCC TNM classification seventh edition, which was introduced in 2010. METHODS: One hundred thirteen patients with malignant tumors of the maxillary sinus were included in this study. The prognostic impact of the TNM classification and the UICC/AJCC seventh edition's stage grouping were analyzed in univariate and multivariate analysis. RESULTS: The UICC/AJCC stage grouping, the T classification, and the N classification had a significant impact on overall survival (OS) in univariate analysis (p < .05). No significant differences were observed between the groups T4a and T4b (p = .109). In multivariate analysis, the UICC/AJCC stage grouping (p = .031), the N classification (p = .014), and age (p < .001) had a significant impact on OS. CONCLUSION: Although UICC/AJCC stage grouping and the N classification provided a significant prediction of OS in univariate and multivariate analysis, T classification only influenced OS in univariate analysis.