Postgraduate training in Oral- and Maxillofacial Surgery: Results of a survey among 74 German interns.

The aim of this study was to asses a survey of residents to obtain relevant information about their current situation in training in Oral and Maxillofacial Surgery in Germany. Special focus was given to the personal and clinical preferences of the residents, their main subjects of interest and plans after residency. Furthermore, the different principles of education at German teaching hospitals were evaluated. Overall, 74 questionnaires were completed on a voluntary and anonymous basis by German residents for Oral and Maxillofacial Surgery. Participants' mean age was 32.74 years (68% male, 27% female). Most participants were in the fifth year of training (32%) and members of the German Association of Oral and Maxillofacial Surgery (70%). This rate increased with progress in residency (p = 0.006). Most residents (70%) were employed at university hospitals, followed by non-university hospitals (26%) and private practices (4%). Residents from university hospitals (3.06 ± 0.39 years) were less advanced in training compared to residents from non-university hospitals and private practices (4.10 ± 0.54 years; p = 0.005). Part-time employed residents were significantly younger (30.64 ± 2.37 years) than full-time employed residents (33.25 ± 0.64 years, p = 0.002). Structured concepts of training existed in 64% of the hospitals, while training depending on the current year of residency (42%) was most common. Most of the residents would prefer a systematic rotation system (59%). Main subjects of clinical interest were aesthetic (50%) and orthognathic surgery (46%). The interest in dento-alveolar surgery (34%) significantly increased with participants' age (p = 0.008). Clefts and malformations were favoured by few residents (16%). Most participants planned to specialize in facial plastic surgery after residency (76%). The data collected might give evidence for an increasing importance of structured training concepts in Oral and Maxillofacial Surgery. It might be relevant to enhance the interest and the excitement of residents for oncology, traumatology, cleft and malformation surgery.

Fractures of the mandibular condyle: A comparison of patients, fractures and treatment characteristics between Groningen (The Netherlands) and Dresden (Germany).

PURPOSE: To explore differences in patient, fracture, accident and treatment characteristics between patients treated for a mandibular condyle fracture in the University Centres of Dresden and Groningen, as an explanation for differences treatment results. MATERIALS AND METHODS: Patients' fracture, accident and treatment characteristics were obtained from the medical records of Dresden and Groningen from January 1, 2008, to August 31, 2011, and were analysed using logistic regression analysis. RESULTS: In Dresden, compared to Groningen, patients were generally older (OR 1.03, 95% CI 1.02; 1.05, per year), were more often male (OR 2.54, 95% CI 1.48; 4.34) and more often had intracapsular (OR 2.95, 95% CI 1.67; 5.22) and low condylar (OR 1.86, 95% CI 1.14; 3.04) fractures. In Groningen 98% of patients received closed treatment and in Dresden 42%. CONCLUSION: Significant differences in patients and fractures and treatments were found between both Centres. These differences can partly be explained by the demographics of the cities and differences in imaging techniques (e.g., computed tomography, Orthopantomogram, Towne projection) applied to identify fractures. This study illustrates that differences in diagnosis, treatment and outcome are not only related to the health care system but also to differences in patient characteristics between centres.

Position paper from the IBRA Symposium on Surgery of the Head--the 2nd International Symposium for Condylar Fracture Osteosynthesis, Marseille, France 2012.

BACKGROUND: This is a position paper from the 2nd International Bone Research Association (IBRA) Symposium for Condylar Fracture Osteosynthesis 2012 was held at Marseille, succeeding the first congress in Strasbourg, France, in 2007. The goal of this IBRA symposium and this paper was to evaluate current trends and potential changes of treatment strategies for mandibular condylar fractures, which remain controversial over the past decades. METHODS: Using a cross-sectional study design, we enrolled the consensus based on the panel of experts and participants in the IBRA Symposium 2012. The outcomes of interest were the panel and electronic votes on management of condylar base, neck and head fractures, and panel votes on endoscopic and paediatric condylar fractures. Appropriate descriptive and univariate statistics were used. RESULTS: The consensus derived from 14 experts and 41 participant surgeons, using 12 case scenarios and 27 statements. The experts and participants had similar decision on the treatment of condylar base, neck and head fractures, as well as similar opinion on complications of condylar fracture osteosynthesis. They had a parallel agreement on using open reduction with internal fixation (ORIF) as treatment of choice for condylar base and neck fractures in adults. Endoscopic approaches should be considered for selected cases, such as condylar base fractures with lateral displacement. There was also a growing tendency to perform ORIF in condylar head fractures. The experts also agreed to treat children (>12 years old) in the same way as adults and to consider open reduction in severely displaced and dislocated fractures even in younger children. Nevertheless, non-surgical treatment should be the first choice for children <6 years of age. The decision to perform surgery in children was based on factors influencing facial growth, appropriate age for ORIF, and disagreement to use resorbable materials in children. CONCLUSIONS: The experts and participating surgeons had comparable opinion on management of condylar fractures and complications of ORIF. Compared to the first Condylar Fracture Symposium 2007 in Strasbourg, ORIF may now be considered as the gold standard for both condylar base and neck fractures with displacement and dislocation. Although ORIF in condylar head fractures in adults and condylar fractures in children with mixed dentition is highly recommended, but this recommendation requires further investigations.

Influence of different modifications of a calcium phosphate cement on resorption and new bone formation: an in vivo study in the minipig.

Calcium phosphate cements (CPCs) are established in surgery as temporary bone replacement materials. The most common and important class of CPC, transformed into nanocrystalline hydroxyapatite after setting, is characterized by good biocompatibility and osteoconductivity. However, acceleration of remodelling is in the focus of ongoing research. In the present study, the bone healing efficacy of Biocement D (BioD) modified with mineralized collagen alone (BioD/coll) or in combination with osteocalcin (BioD/coll/OC), O-phospho-L-serine (BioD/coll/PS), sodium citrate (BioD/coll/cit), and polylactide (BioD/coll/PL), respectively, was evaluated in a large animal model. Resorption of the bone substitutes and new bone formation were studied in cyst-like jaw defects of minipigs after filling with the unmodified BioD and the modified BioD variants, respectively. Histomorphometric analysis revealed small differences between the different cement types with respect to resorption. However, new bone formation was improved in case of defects repaired with BioD/coll/OC and BioD/coll/PS and slightly improved in case of BioD/coll and BioD/coll/PL.

Treatment of fractures of the condylar head with resorbable pins or titanium screws: an experimental study.

We aimed to compare in vivo the stability of fixation of condylar fractures in sheep using sonic bone welding and standard titanium screws. We assessed stability of the osteosynthesis and maintenance of the height of the mandibular ramus. Height decreased slightly in both groups compared with the opposite side. The volume of the condyle increased considerably in both groups mainly because callus had formed. The results showed no significant disadvantages for pin fixation compared with osteosynthesis using titanium screws.

Characterization of the osseointegration of Algipore and Algipore modified with mineralized collagen type I.

OBJECTIVE: Algipore is a clinically established bone substitute. The present study evaluated the osseoconductive and resorptive characteristics of Algipore modified with collagen type I (ACI). STUDY DESIGN: Three defects of 10 × 3 mm were set in the frontal bone of 10 adult female minipigs. One cavity was filled with commercially available Algipore, and the second with ACI. The third cavity was left unfilled and served as reference. After 4 months of healing, the animals were humanely killed. Bone formation and resorption characteristics of the substitutes were evaluated histomorphologically and histomorphometrically using Donath's sawing and grinding technique. RESULTS: Neither material caused inflammatory reactions. Compared with controls, both substitutes showed significantly higher fractions of trabecular bone (control: 42.2%; Algipore: 58.7%, [P < .001]; ACI: 53.6%, [P = .013]). After 4 months, the remaining fraction of Algipore was 42.2% and the fraction of ACI was 47.9% (P = .016). CONCLUSIONS: The present study demonstrates that the modification of Algipore with collagen I does not show any benefits compared with pure Algipore in small calvarial bone defects in minipigs.

Comparison of bone-implant contact and bone-implant volume between 2D-histological sections and 3D-SRµCT slices.

Histological imaging is still considered the gold standard for analysing bone formation around metallic implants. Generally, a limited number of histological sections per sample are used for the approximation of mean values of peri-implant bone formation. In this study we compared statistically the results of bone-implant contact (BIC) and bone-implant volume (BIV) obtained by histological sections, with those obtained by X-ray absorption images from synchrotron radiation micro-computed tomography (SRµCT) using osseointegrated screw-shaped implants from a mini-pig study. Comparing the BIC results of 3-4 histological sections per implant sample with the appropriate 3-4 SRµCT slices showed a non-significant difference of 1.9 % (p = 0.703). The contact area assessed by the whole 3D information from the SRµCT measurement in comparison to the histomorphometric results showed a non-significant difference in BIC of 4.9 % (p = 0.171). The amount of the bone-implant volume in the histological sections and the appropriate SRµCT slices showed a non-significant difference by only 1.4 % (p = 0.736) and also remains non-significant with 2.6 % (p = 0.323) using the volumetric SRµCT information. We conclude that for a clinical evaluation of implant osseointegration with histological imaging at least 3-4 sections per sample are sufficient to represent the BIC or BIV for a sample. Due to the fact that in this study we have found a significant intra-sample variation in BIC of up to ± 35 % the selection of only one or two histological sections per sample may strongly influence the determined BIC.

Biomechanical evaluation of a titanium implant surface conditioned by a hydroxide ion solution.

Two groups of titanium dental implants, identical in geometry but different in the treatment of their surfaces, were tested in an in vivo minipig model of the mandible. The surfaces that were tested were, first, sandblasted and acid-etched; and secondly, sandblasted, acid-etched, and conditioned. The removal torque was assessed at 2, 4, and 8 weeks after implantation (n=6 animals in each healing period). The interfacial stiffness was also evaluated. All dental implants were well-integrated at the time of death. Removal torque values increased significantly over the course of 8 weeks. Removal torque and interfacial stiffness were increased for conditioned surfaces after 2 weeks, but there were no significant differences between the two surfaces. The sandblasted and acid-etched implants are the standard, and conditioning of the surface showed a tendency to increase early peri-implant formation of bone.

Ultrasound-aided resorbable osteosynthesis of fractures of the mandibular condylar base: an experimental study in sheep.

We evaluated the osteosynthesis of condylar fractures using resorbable mini plates and ultrasound-aided insertion of pins clinically and histologically. Stability was greater than that with resorbable screws because of the fusion of pin and plate. Long term evaluation showed complete resorption of the polymeric osteosynthesis material.

The saxon bisphosphonate register - therapy and prevention of bisphosphonate-related osteonecrosis of the jaws.

In 2009, a study group of three Saxon hospitals set up a Saxon register with the aim of including all patients with bisphosphonate (BP) medication. In addition, specific concepts for surgical approach were developed. The target is to define relevant treatment and prevention strategies of bisphosphonate-related osteonecrosis of the jaws (BRONJ) based on high patient population statistics. Since July 2009, all patients with oral or intravenous BP medication have been registered in the 3 Saxon hospitals. Data was systematically acquired in detailed forms. Totally, 258 patients (♂: 83, ♀: 175) were registered by October 2010. 100 patients out of this already had BRONJ which preferably affected the mandible (70%) and was mostly associated with intravenous medication. In 54 cases, treatment was carried out by surgery according to the strategy developed. The criterion for success was absence of symptoms at least for 3 months after surgery. The following stage-dependent success rates were obtained: stage I (13 patients) - 84.6%, stage II (22 patients) - 95.5%, stage III (14 patients) - 85.7%, stage IV (5 patients) - 80%. Under preventive aspects, teeth were extracted after a predefined scheme in 68 of all patients registered as being asymptomatic. No BRONJ was observed in 98.5%; the criterion also being absence of symptoms for a minimum period of 3 months after surgery. Surgical treatment is the treatment of choice in cases of BRONJ. Tooth extractions are rather unproblematic in asymptomatic patients if the predefined scheme is followed.

Three-dimensional fixation of fractures of the mandibular condyle with a resorbable three-dimensional osteosynthesis mesh.

We describe the use of a resorbable mesh fixed by ultrasound-activated pins, and report the satisfactory outcome in the first 5 patients treated.

Stability of fixation of diacapitular fractures of the mandibular condylar process by ultrasound-aided resorbable pins (SonicWeld Rx® System) in pigs.

To assess the stability of osteosynthesis in diacapitular condylar fractures we compared fixation using ultrasound-aided resorbable pins with poly-(D,L)-lactide (SonicWeld® Rx, KLS Martin, Tuttlingen, Germany) with that of titanium screws in 20 pig mandibles, 10 in each group. Isolated diacapitular fractures were created using a surgical chisel. Ten fractures were each repositioned and fixed by two pins (17 and 11 mm long, 2.1mm in diameter), and 10 fractures were fixed by two titanium screws of equal length, 2.0mm in diameter. Shear tests were done immediately after treatment to measure the maximum force to disrupt the fixation. Fixation with pins resisted mean shear forces of 310N until the pins fractured, whereas fixation with titanium screws failed at 918N when the screws pulled out of the bone. Long-term stability and resorption of pins will have to be analysed in an in vivo study.

Comparative evaluation of ten different condylar base fracture osteosynthesis techniques.

The aim of this study on the mandibles of minipigs was to compare the biomechanical stability of different methods of osteosynthesis that are used in the operative treatment of fractures of the base of the condyle. Ten different systems of osteosynthesis were used to fix 164 fractures, which were tested by a two-point bending test after repositioning and fixing. This stress test was applied in four directions: lateral to medial, anterior to distal, distal to anterior, and medial to lateral. The Eckelt lag screw, one or two 2.0mm miniplates, one miniplate with bar (KLS Martin), minicompression plates (Medicon), zygoma compression plates (Medartis), condylus fracture plates (Medartis), square 4-hole plates (KLS Martin), and either one or two resorbable 4-hole miniplates (Resorb-X, Martin) were used for osteosynthesis. A total of 164 tests were done using a universal test machine that measured forces until the osteosynthesis failed. Advantages in mechanical load capacity were also measured for the Eckelt lag screw when force was applied from medial to lateral. Fixation with one resorbable miniplate was not functionally stable. Irrespective of the direction of force applied, two miniplates were the most stable technique. There were pronounced differences depending on the direction of force applied. The results suggest that treatment with a single resorbable miniplate is not functionally stable.

Resorbable triangular plate for osteosynthesis of fractures of the condylar neck.

We describe a new design of resorbable plate for use in the treatment of fractures of the condylar neck, and report the outcome of initial treatment in two patients.

Bone block fixation by ultrasound activated resorbable pin osteosynthesis: a biomechanical in vitro analysis of stability.

OBJECTIVES: The aim of this study was to determine the compound strength of the fixation between 2 blocks of synthetic bone using ultrasound activated resorbable pins (regarding drill hole diameter) and compare them to fixation with titanium miniscrews. Resorbable pins were up to 17 mm long. STUDY DESIGN: Two synthetic bone blocks (Sawbone) were fixed by either a resorbable pin or miniscrew osteosynthesis. Maximum tensile forces were determined mechanically. Pin lengths of 7 mm, 11 mm, and 17 mm were analyzed in relation to different drill hole diameters. RESULTS: The ideal drill hole configuration was a combination of diameters of 2.1/1.6 mm (in a lag screw configuration). Mean maximum tensile force was 80 N for 7 mm pins (105 N/11 mm, 69 N/17 mm). In comparison, tensile forces of titanium screws were 20 N (7 mm), 97 N (11 mm), and 135 N (17 mm). CONCLUSIONS: Osteosynthesis by resorbable pins reached equal compound strength levels compared with titanium miniscrews. This in vitro study was the basis for a clinical trial of ultrasound-guided resorbable pin osteosynthesis.

Mandibular traction--an alternative treatment in infants with Pierre Robin sequence.

PURPOSE: In the Pierre Robin sequence, retrognathia and glossoptosis lead to airway obstruction in infants with or without cleft palate. Mandibular distraction has gained acceptance for the treatment of airway obstruction. However, surgical interventions can result in complications. In our institution, mandibular traction is the standard treatment in cases of severe respiratory distress. PATIENTS AND METHODS: A retrospective study was performed of all infants treated for Pierre Robin sequence at our institution from 1979 to 2007. The diagnosis and type of treatment (positioning/palatal plate or mandibular traction) were evaluated. The palatal plate had several knobs at the anterior alveolar ridge to direct the tongue forward. Mandibular traction was applied using weights transmitted onto the mandible by a custom-made plate fixed at the mandible with circumferential wiring. RESULTS: Nineteen children required airway treatment because of repeated cyanotic episodes and respiratory adaptation disorders. Of these 19 children, 8 had been diagnosed with pure Pierre Robin sequence and 11 also had other congenital abnormalities. Of the 19 patients, 10 (56%) were treated nonoperatively by lateral or prone positioning and/or wearing a palatal plate to stimulate the tongue. In 8 patients, conservative management was not sufficient, and continuous mandibular traction was performed for 2 to 5 weeks using weights of 50 to 200 g. One patient required a tracheostomy because of tracheomalacia. CONCLUSIONS: Surgical therapy using mandibular traction is a minimally invasive alternative to more invasive procedures because no serious complications such as scars or damage to the nerves were encountered.

[Computation and experimental examination of an implant structure made by a fibre-reinforced building method for the bypass of continuity defects of the mandible]. / Berechnung und experimentelle Prüfung einer Implantatstruktur in Faserverbundbauweise für die Uberbrückung von Kontinuitätsdefekten des Unterkiefers.

A partial resection of the lower jaw often has to be carried out in the context of the surgical removal of tumours in the lower jaw, mouth and tongue-floor space and lower jaw fractures with loss of substance, benign bone lesions and extensive difficult inflammation of bone tissue, respectively. The primary reconstruction of the lower jaw after partial resection with loss of continuity is mainly important for functional and aesthetic reasons. The defects of lower jaw continuity are often bridged with metal plates to reconstruct the masticatory function of the lower jaw, temporarily or permanently. Functional as well as aesthetic disadvantages arise in the case of the application of such plates as a result of a high stiffness jump between reconstruction plate and bone and their insufficiently individual design. The employment of biocompatible, carbon-fibre-reinforced Polyetheretherketon (CF-PEEK) permits the development of a geometry- and stiffness-adapted carrying structure for the mandible. For the demand-adapted dimensioning and the test of a CF-PEEK bandage, the application of optical methods, such as the grey value correlation method, is suited as well as numeric methods, such as the finite element method. In an initial analysis of deformation behaviour, the various osteosynthesis configurations are comparatively investigated on a model jaw. The calculations and tests of the lower jaw model show that the use of the new CF-PEEK bandage compared to the use of conventional titanium osteosynthesis plates shows a mechanical behaviour which is much better adapted to the natural lower jaw.

Open reduction and internal fixation versus closed treatment and mandibulomaxillary fixation of fractures of the mandibular condylar process: a randomized, prospective, multicenter study with special evaluation of fracture level.

PURPOSE: This randomized, clinical multicenter trial investigated the treatment outcomes of displaced condylar fractures, and whether radiographic fracture level was a prognostic factor in therapeutic decision-making between open reduction and internal fixation (ORIF) versus closed reduction and mandibulomaxillary fixation (CRMMF). PATIENTS AND METHODS: Sixty-six patients with 79 displaced fractures (deviation of 10 degrees to 45 degrees, or shortening of the ascending ramus >or=2 mm) of the condylar process of the mandible at 7 clinical centers were enrolled. Patients were randomly allocated to CRMMF (n = 30 patients) or ORIF (n = 36 patients) treatment. The following parameters were measured 6 months after the trauma. Clinical parameters included mouth opening, protrusion, and laterotrusion. Radiographic parameters included level of the fracture, deviation of the fragment, and shortening of the ascending ramus. Subjective parameters included pain (according to a visual analogue scale), discomfort, and subjective functional impairment with a mandibular functional impairment questionnaire. RESULTS: The difference in average mouth opening was 12 mm (P or=2 mm, should be treated with ORIF, irrespective of level of the fracture.