Uwe Eckelt

Publications of Uwe Eckelt

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

  Authors: Matthias Schneider, Bernd Stadlinger, Richard Loukota, Uwe Eckelt

  The British journal of oral & maxillofacial surgery. 12/2011;

  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.

  Authors: Bernd Stadlinger, Vera Hintze, Susanne Bierbaum, Stephanie Möller, Matthias C Schulz, Ronald Mai, Eberhard Kuhlisch, Sascha Heinemann, Dieter Scharnweber, Matthias Schnabelrauch, Uwe Eckelt

  Journal of biomedical materials research. Part B, Applied biomaterials. 11/2011;

  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, weBiological 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. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.

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

  Authors: Matthias Schneider, Claudia Seinige, Eckart Pilling, Michael Rasse, Richard Loukota, Bernd Stadlinger, Ronald Mai, Uwe Eckelt

  The British journal of oral & maxillofacial surgery. 11/2011;

  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 withWe 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.

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

  Authors: Matthias Schneider, Uwe Eckelt, Bernd Reitemeier, Heike Meissner, Gerd Richter, Richard Loukota, Bernd Stadlinger

  The British journal of oral & maxillofacial surgery. 06/2011; 49(4):297-301.

  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,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.

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

  Authors: Bernd Stadlinger, Stephen J Ferguson, Uwe Eckelt, Roland Mai, Anna Theresa Lode, Richard Loukota, Falko Schlottig

  The British journal of oral & maxillofacial surgery. 12/2010; 50(1):74-9.

  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 testedTwo 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.

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

  Authors: Günter Lauer, Winnie Pradel, Henry Leonhardt, Richard Loukota, Uwe Eckelt

  The British journal of oral & maxillofacial surgery. 11/2009;

  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.

• Comparative evaluation of ten different condylar base fracture osteosynthesis techniques.

  Authors: Eckart Pilling, Uwe Eckelt, Richard Loukota, Konrad Schneider, Bernd Stadlinger

  The British journal of oral & maxillofacial surgery. 10/2009;

  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 baseThe 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.

• Surface-conditioned dental implants: an animal study on bone formation.

  Authors: Bernd Stadlinger, Anna Theresa Lode, Uwe Eckelt, Ursula Range, Falko Schlottig, Thomas Hefti, Ronald Mai

  Journal of clinical periodontology. 10/2009;

  Stadlinger B, Lode AT, Eckelt U, Range U, Schlottig F, Hefti T, Mai R. Surface-conditioned dental implants: an animal study on bone formation. J Clin Periodontol 2009. doi:Stadlinger B, Lode AT, Eckelt U, Range U, Schlottig F, Hefti T, Mai R. Surface-conditioned dental implants: an animal study on bone formation. J Clin Periodontol 2009. doi: 10.1111/j.1600-051X.2009.01466.x. Abstract Aim: The aim of this study was to determine whether bone formation around surface-conditioned implants is enhanced compared with non-surface-conditioned sandblasted acid-etched titanium implants. Materials and Methods: One hundred and forty-four implants were placed in the mandible of 18 minipigs. Before placement, implants were either surface conditioned in a solution containing hydroxide ions (conSF) or assigned to controls. Animals were euthanized after 2, 4 and 8 weeks of submerged healing, the 8-week group receiving polyfluorochrome labelling at week 2, 4, 6 and 8. One jaw quadrant per animal was selected for histological and histomorphometrical evaluation of mineralized bone-implant contact (mBIC), osteoid-implant contact (OIC) and bone volume (BV) analysis. Results: Polyfluorochrome labelling showed no general differences in bone dynamics. mBIC showed the most pronounced differences after 2 weeks, reaching 65.5% for conSF compared with 48.1% for controls, p=0.270. Differences levelled out after 4 weeks (67.4% control, 65.7% conSF) and 8 weeks (64.0% control, 70.2% conSF). OIC levels were initially comparable, showing a slower decline for conSF after 4 weeks. BV was higher for conSF at all times. No significant differences could be found. Conclusion: A tendency towards increased mBIC was shown for surface-conditioned implants after short-term healing.

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

  Authors: Matthias Schneider, Richard Loukota, Bernd Reitemeier, Heike Meissner, Bernd Stadlinger, Uwe Eckelt, Gerd Richter

  Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics. 10/2009;

  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)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.

  Authors: Winnie Pradel, Günter Lauer, Jürgen Dinger, Uwe Eckelt

  Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons. 10/2009; 67(10):2232-7.

  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 treatmentPURPOSE: 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.

• Increased bone formation around coated implants.

  Authors: Bernd Stadlinger, Susanne Bierbaum, Silke Grimmer, Matthias C Schulz, Eberhard Kuhlisch, Dieter Scharnweber, Uwe Eckelt, Ronald Mai

  Journal of clinical periodontology. 07/2009;

  Aim: We hypothesized that coating threaded, sandblasted acid-etched titanium implants with collagen and chondroitin sulphate (CS) increases bone formation and implant stability, compared withAim: 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.

• Reduction of diacapitular fractures of the mandibular condyle using a special repositioning pin.

  Authors: Matthias Schneider, Richard Loukota, Uwe Eckelt

  The British journal of oral & maxillofacial surgery. 01/2009;

• 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.

  Authors: Matthias Schneider, Francois Erasmus, Klaus Louis Gerlach, Eberhard Kuhlisch, Richard A Loukota, Michael Rasse, Johannes Schubert, Hendrik Terheyden, Uwe Eckelt

  Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons. 01/2009; 66(12):2537-44.

  PURPOSE: This randomized, clinical multicenter trial investigated the treatment outcomes of displaced condylar fractures, and whether radiographic fracture level was a prognostic factor inPURPOSE: 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 >/=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 </= .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 </= .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 >/=2 mm, should be treated with ORIF, irrespective of level of the fracture.

• O-phospho-l-serine: a modulator of bone healing in calcium-phosphate cements.

  Authors: Ronald Mai, Romy Lux, Peter Proff, Günter Lauer, Winnie Pradel, Henry Leonhardt, Antje Reinstorf, Michael Gelinsky, Roland Jung, Uwe Eckelt, Tomasz Gedrange, Bernd Stadlinger

  Biomedizinische Technik. Biomedical engineering. 10/2008;

  Abstract Bone substitution materials are seen as an alternative to autogenous bone transplants in the reconstruction of human bone structures. The aim of the present animal study was to evaluate theAbstract Bone substitution materials are seen as an alternative to autogenous bone transplants in the reconstruction of human bone structures. The aim of the present animal study was to evaluate the clinical handling and the conditions of bone healing after the application of a phosphoserine and collagen-I-modified calcium-phosphate cement (Biozement D). The application of phosphoserine is supposed to influence the texture of the extracellular matrix. Standardised bone defects were created in the lower jaw of 10 adult minipigs. These defects were reconstructed with a pasty calcium-phosphate cement mixture. After a healing time of 4 months, the animals were sacrificed. The mandibles of all animals were resected and non-decalcified histological sections of the areas of interest were prepared. The experiment was evaluated by means of qualitative histology and histomorphometry. The hydroxyapatite cement entirely hardened intraoperatively. Modelling and handling of the cement was facile and the margin fit to the host bone was excellent. Histology showed that resorption started in the periphery and proceeded exceptionally fast. The bony substitution, especially in phosphoserine-endowed cements, was very promising. After a healing period of 4 months, phosphoserine cements showed a bone regeneration of nearly two-thirds of the defect sizes. In the applied animal experiment, the newly developed hydroxyapatite collagen-I cement is well suited for bone substitution due to its easy handling, its excellent integration and good resorption characteristics. The addition of phosphoserine is very promising in terms of influencing resorption features and bone regeneration.

• Microsatellite instability and loss of heterozygosity in squamous cell carcinoma of the head and neck.

  Authors: Susanne Koy, Jens Plaschke, Hella Luksch, Katrin Friedrich, Eberhard Kuhlisch, Uwe Eckelt, Ramon Martinez

  Head & neck. 08/2008; 30(8):1105-1113.

  BACKGROUND.: Microsatellite instability (MSI) in head and neck squamous cell carcinoma (HNSCC) has been reported with a wide range of frequencies. The aim of our study was to disclose the frequencyBACKGROUND.: Microsatellite instability (MSI) in head and neck squamous cell carcinoma (HNSCC) has been reported with a wide range of frequencies. The aim of our study was to disclose the frequency and basis of MSI in HNSCC and to correlate MSI and findings on loss of heterozygosity (LOH) with the clinical data. METHODS.: We analyzed MSI and LOH in 91 tumors. All tumors presenting instability were analyzed for the expression of mismatch repair genes (MMR) proteins. RESULTS.: Low-level microsatellite instability (MSI-L) was seen in 7.7% of the HNSCC. None of the MSI-L tumors had aberrant MMR protein expression. LOH rates up to 57% were identified for different regions on chromosome 3p. For the marker D10S197, we found a significant correlation between LOH and tumor stage IV. CONCLUSION.: Our results indicate that MMR gene inactivation is rare among primary HNSCC. In contrast, the MSI-L phenotype plays a role in a small subset of tumors. LOH on chromosome arm 3p and 10p12 seems to be involved in tumorigenesis and progression HNSCC, respectively. (c) 2008 Wiley Periodicals, Inc. Head Neck 30: 1105-1113, 2008.

• Experimental investigations for mechanical joint strength following ultrasonically welded pin osteosynthesis.

  Authors: Heike Meissner, Eckart Pilling, Gert Richter, Rainer Koch, Uwe Eckelt, Bernd Reitemeier

  Journal of materials science. Materials in medicine. 07/2008; 19(6):2255-9.

  The purpose of this study was to determine whether fixation of cranial bone segments using ultrasonically welded pin osteosynthesis showed differences in mechanical stability as compared to fixationThe purpose of this study was to determine whether fixation of cranial bone segments using ultrasonically welded pin osteosynthesis showed differences in mechanical stability as compared to fixation of cranial bone segments using screw osteosynthesis. Right and left cranial bone segments from each of 16 young sheep were obtained by craniotomy and re-fixed: on the right with a mesh plate and pins, and on the left with a mesh plate and screws. All osteosynthesis materials consisted of PDLLA, fully amorphous polyactid. A total of 167 cranial bone / mesh plate segments from 16 animals were investigated; 84 segments were pin-fixed and 83 segments were screw-fixed. The implantation time of the re-fixed segments ranged from 1 day to 196 days. The mechanical methods chosen for simulation of stress on the bone segment bonds were two bending tests (horizontal and vertical directions) and a tensile test. The values obtained in the mechanical tests indicate differences in the bond strength between the pin- and screw- fixation methods over the length of in vivo implantation time. The mechanical stability of the ultrasonically welded pin osteosynthesis bonds over the screw osteosynthesis bonds proved to be statistically significant. The implication of these findings should also be relevant in the field of medicine.

• Suitability of differently designed matrix-based implant surface coatings: An animal study on bone formation.

  Authors: Bernd Stadlinger, Eckart Pilling, Matthias Huhle, Evgenij Khavkin, Susanne Bierbaum, Dieter Scharnweber, Eberhard Kuhlisch, Uwe Eckelt, Ronald Mai

  Journal of biomedical materials research. Part B, Applied biomaterials. 06/2008;

  Introduction: The aim of the present study was to assay how bone formation around dental implants is influenced by differently composed collagen matrices and RGD peptide as implant surface coatingsIntroduction: The aim of the present study was to assay how bone formation around dental implants is influenced by differently composed collagen matrices and RGD peptide as implant surface coatings compared to a sandblasted titanium surface. Material and Methods: Five different implant surface coatings were designed: titanium (sandblasted), collagen type I, collagen type I&III, RGD-peptide, and mineralized collagen. Sixty experimental implants of a square-shaped design were inserted into the mandibles of 12 minipigs, 3 months following extraction of the premolar teeth. During the 6-month study period, sequential polyfluorochrome labeling was performed. After sacrifice, bone implant contact (BIC) was evaluated using histologic and histomorphometric methods. Results: New bone formation was observed against all implant surfaces. Polyfluorochrome labeling showed that bone growth started from the host bone in the majority of samples. The highest BIC was measured for collagen I and collagen I/III coated implants; however, significant differences between the coatings could not be found. Conclusion: Osseointegration was achieved for all implant surfaces. Although a statistically significant increase in BIC could not be demonstrated for the experimental coatings after the 6 months study period, there was also no discernible detrimental effect of the coatings in comparison to the uncoated titanium surfaces. (c) 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008.

• Effect of biological implant surface coatings on bone formation, applying collagen, proteoglycans, glycosaminoglycans and growth factors.

  Authors: Bernd Stadlinger, Eckart Pilling, Ronald Mai, Susanne Bierbaum, Ricardo Berhardt, Dieter Scharnweber, Uwe Eckelt

  Journal of materials science. Materials in medicine. 04/2008; 19(3):1043-9.

  OBJECTIVES: The aim of the present study was to evaluate six different implant surface coatings with respect to bone formation. Being major structural components of the extracellular matrix,OBJECTIVES: The aim of the present study was to evaluate six different implant surface coatings with respect to bone formation. Being major structural components of the extracellular matrix, collagen, the non-collagenous components decorin/chondroitin sulphate (CS) and the growth factors TGF-beta1/BMP-4 served in different combinations as coatings of experimental titanium implants. MATERIALS AND METHODS: Eight miniature pigs received each six implants in the mandible. The implant design showed two circular recesses along the length axis. Three, four, five and six weeks after implant placement, the animals were sacrificed in groups of two. Bone-implant contact (BIC) was evaluated along the outer implant surface and within the recesses. Bone volume was determined by synchrotron radiation micro computed tomography (SRmicroCT) for one implant of each surface state, 6 weeks after placement. RESULTS: At each week of observation, collagen/CS or collagen/CS/BMP-4 coated implants showed the highest BIC of all surface states. This was statistically significant at week five (p=0.030, p=0.040) and six (p=0.025, p=0.005). SRmicroCT measurements determined the highest bone volume for a collagen/CS coated implant. CONCLUSION: The results indicate that collagen/CS and collagen/CS/BMP-4 lead to a higher degree of bone formation compared to other ECM components.

• Histologic study of incorporation and resorption of a bone cement-collagen composite: an in vivo study in the minipig.

  Authors: Ronald Mai, Antje Reinstorf, Eckart Pilling, Matthias Hlawitschka, Roland Jung, Michael Gelinsky, Matthias Schneider, Richard Loukota, Wolfgang Pompe, Uwe Eckelt, Bernd Stadlinger

  Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics. 04/2008; 105(3):e9-14.

  OBJECTIVE: Calcium phosphates are clinically established as bone defect fillers. They have the capability of osseoconduction and are characterized by a slow resorption process. The present studyOBJECTIVE: Calcium phosphates are clinically established as bone defect fillers. They have the capability of osseoconduction and are characterized by a slow resorption process. The present study evaluated the suitability of a newly developed calcium phosphate cement modified with collagen type I. STUDY DESIGN: The modified cement paste was inserted in differently designed defects of 10 minipigs. Further, an alveolar ridge augmentation was performed, applying the cement paste. The cement hardened in situ during the operation, forming a hydroxyapatite collagen composite. Animals were sacrificed after 1, 3, 6, 12, and 18 months. The tissue integration and resorption process was then evaluated using nondecalcified microsections. All animals were evaluated for histology. RESULTS: The implanted material showed osseoconductive characteristics. Resorption started from the edge of the defect zone, and bone substitution followed rapidly. Twelve months after placement of the cement, complete remodeling was observed. CONCLUSION: It can be concluded that the applied hydroxyapatite-collagen cement composite shows good resorption and bone integration.

• [In Process Citation]

  Authors: Werner Hufenbach, Robert Gottwald, Jutta Markwardt, Uwe Eckelt, Niels Modler, Bernd Reitemeier

  Biomedizinische Technik. Biomedical engineering. 02/2008; 53(6):306-13.

  Abstract 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 withAbstract 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.