Eckart Pilling

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.

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

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 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.

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

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 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.

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.

Frei modellierbare Hydroxylapatit-Kollagen-Komposite zur Sanierung ossärer Defekte

AIM In the following study we evaluated the biological response of a new freely moldable bone substitute in an animal model. MATERIAL AND METHODS Critically sized defects were created surgically in the lower jaw of ten adult minipigs. The drill defects were filled with hydroxyapatite collagen paste. After observation periods of 1, 3, 6, 12, and 18 months the mandibles were harvested without wound healing defects for histological evaluation of resorption and bone ingrowth with a sawing and grinding technique. RESULTS The result of the remodeling process was a complete degradation of hydroxyapatite collagen implants after 12-18 months with reorganization of vital trabeculae oriented in a mature pattern. CONCLUSION The hydroxyapatite collagen cement works as an osteoconductor and shows signs of direct osseointegration and resorption.Das Ziel der vorliegenden Untersuchung war die tierexperimentelle Evaluation der Eignung eines neu entwickelten Kalziumphosphatzementes als frei modellierbares Hydroxylapatit-Kollagen-Konstrukt zur Knochendefektsanierung. An zehn adulten Minischweinen wurden artifizielle Defekte kritischer Größe gesetzt und mit Knochenersatzmaterial auf der Basis eines pastösen Hydroxylapatit-Kollagen-I-Gemisches remodelliert. Die Versuchsauswertung erfolgte mittels histologischer Imageanalyse am unentkalkten Trenn-Dünnschliff-Präparat. Alle zehn Tiere konnten postoperativ unter komplikationsloser Einheilung nach 1, 3, 6, 12 und 18 Monaten einer histomorphometrischen Bewertung zugeführt werden. Histologisch imponierte initial eine minimale Entzündungsreaktion des Implantatbettes. Der intra operationem aushärtende Hydroxylapatit-Kollagen-Zement zeigte osteokonduktive Materialeigenschaften. Die vom Defektrand ausgehende Resorption und knöcherne Substitution gestaltete sich außergewöhnlich rasch. Nach zwölfmonatiger Liegedauer konnte ein vollständiges knöchernes Remodeling nachgewiesen werden. Das neu entwickelte Hydroxylapatit-Kollagen-I-Komposit eignet sich sowohl aufgrund seiner knöchernen Integration und Resorption als auch durch seine gute Applizierbarkeit intra operationem als Knochenersatzmaterial am verwendeten Tiermodell. In the following study we evaluated the biological response of a new freely moldable bone substitute in an animal model. Critically sized defects were created surgically in the lower jaw of ten adult minipigs. The drill defects were filled with hydroxyapatite collagen paste. After observation periods of 1, 3, 6, 12, and 18 months the mandibles were harvested without wound healing defects for histological evaluation of resorption and bone ingrowth with a sawing and grinding technique. The result of the remodeling process was a complete degradation of hydroxyapatite collagen implants after 12–18 months with reorganization of vital trabeculae oriented in a mature pattern. The hydroxyapatite collagen cement works as an osteoconductor and shows signs of direct osseointegration and resorption.