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.

Site-Specific Variations in Bone Mineral Density under Systemic Conditions Inducing Osteoporosis in Minipigs.

Osteoporosis is a systemic bone disease with an increasing prevalence in the elderly population. There is conflicting opinion about whether osteoporosis affects the alveolar bone of the jaws and whether it poses a risk to the osseointegration of dental implants. The aim of the present study was to evaluate the effects of systemic glucocorticoid administration on the jaw bone density of minipigs. Thirty-seven adult female minipigs were randomly divided into two groups. Quantitative computed tomography (QCT) was used to assess bone mineral density BMD of the lumbar spine as well as the mandible and maxilla, and blood was drawn. One group of minipigs initially received 1.0 mg prednisolone per kg body weight daily for 2 months. The dose was tapered to 0.5 mg per kg body weight per day thereafter. The animals in the other group served as controls and received placebo. QCT and blood analysis were repeated after 6 and 9 months. BMD was compared between the two groups by measuring Hounsfield units, and serum levels of several bone metabolic markers were also assessed. A decrease in BMD was observed in the jaws from baseline to 9 months. This was more pronounced in the prednisolone group. Statistically significant differences were reached for the mandible (p < 0.001) and the maxilla (p < 0.001). The administration of glucocorticoids reduced the BMD in the jaws of minipigs. The described model shows promise in the evaluation of osseointegration of dental implants in bone that is compromised by osteoporosis.

Proteomics and metabolomics for in situ monitoring of wound healing.

Wound healing of soft tissue and bone defects is a complex process in which cellular differentiation and adaption are regulated by internal and external factors, among them are many different proteins. In contrast to insights into the significance of various single proteins based on model systems, the knowledge about the processes at the actual site of wound healing is still limited. This is caused by a general lack of methods that allow sampling of extracellular factors, metabolites, and proteins in situ. Sampling of wound fluids in combination with proteomics and metabolomics is one of the promising approaches to gain comprehensive and time resolved data on effector molecules. Here, we describe an approach to sample metabolites by microdialysis and to extract proteins simultaneously by adsorption. With this approach it is possible (i) to collect, enrich, and purify proteins for a comprehensive proteome analysis; (ii) to detect more than 600 proteins in different defects including more than 100 secreted proteins, of which many proteins have previously been demonstrated to have diagnostic or predictive power for the wound healing state; and (iii) to combine continuous sampling of cytokines and metabolites and discontinuous sampling of larger proteins to gain complementary information of the same defect.

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.

Coating with artificial matrices from collagen and sulfated hyaluronan influences the osseointegration of dental implants.

Dental implants are an established therapy for oral rehabilitation. High success rates are achieved in healthy bone, however, these rates decrease in compromised host bone. Coating of dental implants with components of the extracellular matrix is a promising approach to enhance osseointegration in compromised peri-implant bone. Dental titanium implants were coated with an artificial extracellular matrix (aECM) consisting of collagen type I and either one of two regioselectively low sulfated hyaluronan (sHA) derivatives (coll/sHA1Δ6s and coll/sHA1) and compared to commercial pure titanium implants (control). After extraction of the premolar teeth, 36 implants were inserted into the maxilla of 6 miniature pigs (6 implants per maxilla). The healing periods were 4 and 8 weeks, respectively. After animal sacrifice, the samples were evaluated histomorphologically and histomorphometrically. All surface states led to a sufficient implant osseointegration after 4 and 8 weeks. Inflammatory or foreign body reactions could not be observed. After 4 weeks of healing, implants coated with coll/sHA1Δ6s showed the highest bone implant contact (BIC; coll/sHA1Δ6s: 45.4%; coll/sHA1: 42.2%; control: 42.3%). After 8 weeks, a decrease of BIC could be observed for coll/sHA1Δ6s and controls (coll/sHA1Δ6s: 37.3%; control: 31.7 %). For implants coated with coll/sHA1, the bone implant contact increased (coll/sHA1: 50.8%). Statistically significant differences could not be observed. Within the limits of the current study, aECM coatings containing low sHA increase peri-implant bone formation around dental implants in maxillary bone compared to controls in the early healing period.

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.

Planning implant positions for an auricular prosthesis with digital data.

The esthetic result of an auricular prosthesis is influenced by the position of the prosthesis incorporating the implants. The entire surface of the patient's head is captured by means of a conventional computed tomography (CT). The digital data are used to mirror the contralateral unimpaired ear for restoration of the impaired side. The virtual ear is integrated into a template covering the auricular defect and indexed to the nasal area with computer-aided technology (CAD/CAM). This virtual template is converted into an acrylic resin template. With that the surgeon and the anaplastologist should determine the optimal implant position of the auricular prosthesis.

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.

Biological functionalization of dental implants with collagen and glycosaminoglycans-A comparative study.

Biological implant surface coatings are an emerging technology to increase bone formation. Such an approach is of special interest in anatomical regions like the maxilla. In the present study, we hypothesized that the coating of titanium implants with components of the organic extracellular matrix increases bone formation and implant stability compared to an uncoated reference. The implants were coated using collagen-I with either two different concentrations of chondroitin sulfate (CS) or two differentially sulfated hyaluronans. Implant coatings were characterized biochemically and with atomic force microscopy. Histomorphometry was used to assess bone-implant contact (BIC) and bone-volume density (BVD) after 4 and 8 weeks of submerged healing in the maxilla of 20 minipigs. Further, implant stability was measured by resonance frequency analysis (RFA). Implants containing the lower CS concentration had significantly more BIC, compared to the uncoated reference at both times of interest. No significant increase was measured from week 4 to 8. Differences in BVD and RFA were statistically not significant. A higher concentration of CS and the application of sulfated hyaluronans showed no comparable increase in BIC. This study demonstrates a positive effect of a specific collagen-glycosaminoglycan combination on early bone formation in vivo.

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.