Uwe Eckelt

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= .001) between both treatment groups. The average pain level (visual analogue scale from 0 to 100) was 25 after CRMMF, and 1 after ORIF (P <or= .001). In 53 unilateral fractures, better functional results were observed for ORIF compared with CRMMF, irrespective of fracture level (condylar base, neck, or intracapsular head). Unexpectedly, the subjective discomfort level decreased with ascending level of the fracture. In patients with bilateral condylar fractures, ORIF was especially advantageous. CONCLUSION Fractures with a deviation of 10 degrees to 45 degrees, or a shortening of the ascending ramus >or=2 mm, should be treated with ORIF, irrespective of level of the fracture.

Genetic polymorphisms of drug-metabolizing enzymes and susceptibility to oral cavity cancer

We investigated the association of polymorphisms of drug-metabolizing enzymes and susceptibility to oral cavity cancer. Polymerase chain reaction (PCR)-based analyses were performed on genomic DNA of 94 Caucasian patients in Germany and 92 healthy German controls to determine genotypes of polymorphisms in CYP1A1, GSTM1 and NAT2. For CYP1A1, the homozygous mutant genotype Val/Val did not occur. The heterozygous genotype Ile/Val (6.5% cases versus 4.3% controls) and the homozygous wild-type Ile/Ile (95.7% cases versus 93.5% controls) showed no statistically significant differences between groups (X(2)=0.47; P=0.534, Fishers exact test, two-sided). The GSTM1 homozygous null genotype occurred more frequently in cancer patients (59.6%) compared to controls (53.3%) but this difference remained insignificant in X(2)-analysis (X(2)=1.07; P=0.587). Almost identical genotype distributions between cases and controls were found for all three NAT2 acetylators. Hence, these three genetic polymorphisms are unlikely to be associated with oral cavity cancer in the population studied.

Comparison of zirconia and titanium implants after a short healing period. A pilot study in minipigs

The aim of this animal study was to investigate and compare the osseointegration of zirconia and titanium dental implants. 14 one-piece zirconia implants and 7 titanium implants were inserted into the mandibles of 7 minipigs. The zirconia implants were alternately placed submerged and non-submerged. To enable submerged healing, the supraosseous part was removed, using a diamond saw. The titanium implants were all placed submerged. After a healing period of 4 weeks, a histological analysis of the soft and hard tissue and a histomorphometric analysis of the bone-implant contact (BIC) and relative peri-implant bone-volume density (rBVD; relation to bone-volume density of the host bone) was performed. Two zirconia implants were found to be loose. All other implants were available for evaluation. For submerged zirconia and titanium implants, the implant surface showed an intimate connection to the neighbouring bone, with both types achieving a BIC of 53%. For the non-submerged zirconia implants, some crestal epithelial downgrowth could be detected, with a resultant BIC of 48%. Highest rBVD values were found for submerged zirconia (80%), followed by titanium (74%) and non-submerged zirconia (63%). The results suggest that unloaded zirconia and titanium implants osseointegrate comparably, within the healing period studied.

Analysis of complications in fractures of the mandibular angle—a study with finite element computation and evaluation of data of 277 patients

AIM The purpose of this study was to compute the load on different osteosynthesis plates in a simplified model using finite element analysis, and to find out whether miniplates were sufficiently stable for application at the mandibular angle. PATIENTS Data from 277 patients with 293 fractures of the mandibular angle have been evaluated. METHODS A computation model using finite elements was established in order to compute mechanical stress occurring in osteosynthesis plates used for fixation of fractures of the mandibular angle. In the second part of this study, the data from all in-patients treated for fracture of the mandibular angle were evaluated retrospectively. Age and sex of the patients, cause of fracture, state of dentition, type of therapy as well as complications were noted. RESULTS In those tests, both the 1.0 mm miniplate and the 2.3 mm module plate were sufficiently stable. The rate of major complications (requiring revisional surgery with general anaesthesia) amounted to approximately 17% in comminuted fractures, or in non-compliant patients in which primary stability with a single miniplate did not appear sufficient, so that other osteosynthesis methods were used in addition. This rate was considerably higher than that in simple mandibular fractures. Simple fractures of the mandibular angle were just treated with one miniplate following Champys guidelines strictly. In these fractures the rate of major complications was only 2.3%. CONCLUSION In comminuted fractures and in non-compliant patients, the use of a stronger osteosynthesis material should be considered while in all other cases application of a single 1.0 mm miniplate was regarded as sufficient for fixation using open reduction.

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.

Clinical and radiological evaluation following surgical treatment of condylar neck fractures with lag screws

It was the purpose of this study to evaluate the outcome of lag screw osteosynthesis in severely displaced fractures or fracture dislocations of the mandibular condyle as well as intra- and postoperative complications of this technique. From 1980 to 1996 a total of 492 patients with condylar fractures were treated with lag screw osteosynthesis. Clinical and radiological follow-ups were carried out in 230 patients with severely displaced fractures or fracture dislocations of the mandibular condyle. The period between surgery and follow-up was between 6 months and 2 years. The majority of the clinical results were satisfactory presumably due to the anatomically exact reduction of the fragment (93.4%). Extreme anatomic variations of the mandible (5.8%) and incorrect application of the technique (8.8%) resulted in reduced functional stability of lag screw osteosynthesis. Insufficient fragment reduction and postoperative complications (such as wound infection) entailed restriction of mandibular mobility and arthrotic deformations were seen as persistent radiological irregularities of the mandible. It has been possible to avoid complications and to achieve favourable functional results in complicated fractures of the mandibular condyle by applying strict indications for lag screw osteosynthesis and by considering the individual anatomical peculiarities.

Reduction of postoperative lymphedema after oral tumor surgery with sodium selenite

The objective of this double-blind, randomized study was to establish whether sodium selenite administered orally or intravenously reduces postoperative lymphedema after oral tumor surgery and to study the effect of sodium selenite on glutathione peroxidase (GPX) activity and oxygen radical production. Twenty patients were enrolled in the study. Each of the participants received 1000 μg sodium selenite intravenously or orally daily for 3 wk during the pre-, intra-, and postoperative period. The extent of lymphedema was measured for 2 wk and the plasma and whole-blood selenium concentration, GPX, reactive oxygen species (ROS), NO, and malonic dialdehyde were measured for 1 yr postoperatively. There was an inverse correlation between the severity of the lymphedema and the wholeblood/plasma selenium concentration and GPX activity. In addition, a positive correlation between the ROS concentration and the extent of lymphedema was observed. A significant reduction of lymphedema occurred in the sodium selenite-treated group. It is concluded that sodium selenite represents a suitable adjuvant treatment of secondary lymphedema in surgically treated patients with tumors in the oral and maxillofacial areas. Treatment with sodium selenite is especially advantageous as it can be instituted immediately after surgery prior to wound healing when manual lymphatic decongestion therapy cannot be applied.

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.

Increased bone formation around coated implants.

AIM We hypothesized that coating threaded, sandblasted acid-etched titanium implants with collagen and chondroitin sulphate (CS) increases bone formation and implant stability, compared with uncoated controls. MATERIALS AND METHODS Three different implant surface conditions were applied: (1) sandblasted acid-etched (control), (2) collagen/chondroitin sulphate (low-dose--CS1), (3) collagen/chondroitin sulphate (high-dose--CS2). Sixty 9.5 mm experimental implants were placed in the mandible of 20 minipigs. Bone-implant contact (BIC) and relative peri-implant bone-volume density (rBVD--relation to bone-volume density of the host bone) were assessed after 1 and 2 months of submerged healing. Implant stability was measured by resonance frequency analysis (RFA). RESULTS After 1 month, coated implants had significantly more BIC compared with controls (CS1: 68%, p<0.0001, CS2: 63%, p=0.009, control: 52%). The rBVD was lower for all surface conditions, compared with the hostbone. After 2 months, BIC increased for all surfaces. No significant differences were measured (CS1: 71%, p=0.016, CS2: 68%, p=0.67, control: 63%). The rBVD was increased for coated implants. RFA values were 71-77 at implantation, 67-73 after 1 month and 74-75 after 2 months. Differences in rBVD and RFA were not statistically significant. CONCLUSIONS Data analysis suggests that collagen/CS has a positive influence on bone formation after 1 month of endosseous healing.

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.