Aim: This study aimed to investigate the ability of vascularized periosteum to induce bone formation under functional loading in vivo. Method: Sixteen juvenile mini pigs were used, assigned in 4 different groups. In goup A, a 1,4 cm rib gap was internally þxated and the periosteum ßap was entirely preserved and sutured in situ. In group B the same method was followed, but the periosteum adjacent to the gap was completely excised. In group C, the periosteum was preserved; þxation was used and in addition to these, a biologically inert cement was used to obliterate the marrow cavities at the osteotomy sites. Finally, group D (control) included animals in which the gap was left without þxation and periosteum was completely removed. Specimens were harvested at 8 weeks and were evaluated macroscopically, radiologically and histopathologically. Data was analyzed using Fisherñs exact test and non-parametric statistics. Results: Results of this study showed that all gaps created in group A and 10 of 11 in group C demonstrated complete bone formation, bridging the entire defect. No traces of bone formation were observed in groups B and D. Conclusion: Rib periosteum has extremely high osteogenic capacity and can bridge large defects in vivo under the following conditions: a) its vascular supply is preserved and b) rigid þxation and functional loading is applied.

Purpose: To investigate whether osteosynthesis with biodegradable plates and screws of an unstable part of the zygomatic arch in pigs could provide sufficient fixation for normal bone healing in the area.

Material and Methods: Six healthy pigs were operated under general anesthesia. Two osteotomy lines were created in the right zygomatic arches of the animals leaving the central part of the arch free. This part then was fixated with 2,0 mm Lactosorb® (Walter Lorenz Surgical, Inc., Jacksonville, FL,USA) plates and screws. The left zygomatic arches of the animals were osteotomized in the same fashion but were left without fixation, serving as controls.

Animals were sacrificed at 4,6,8 and 10 weeks. Specimens were evaluated macroscopically, radiographically and histopathologically.

Results: The histopathologic analysis showed that 4 of 6 fixated specimens from the experimental site demonstrated lack of callus formation and bone continuity.

Conclusion: These results indicate that biodegradable osteosynthesis in load bearing areas of the middle third of the facial skeleton provides most likely no sufficient fixation for callus formation and bone healing.

This study aimed to investigate the ability of vascularized periosteum to induce bone formation under functional loading in vivo.

To achieve this, a gap was created in the ribs of mini pigs while functional loading was provided by the respiratory movements.

Sixteen juvenile mini pigs were used, assigned in 4 different groups. In group A, a 1,4 cm rib gap was internally fixated (KLS Martin LP 2,0 mm mini plates and screws) and the periosteum flap was entirely preserved and sutured in situ. In group B the same method was followed, but the periosteum adjacent to the gap was completely excised. In group C, the periosteum was preserved; fixation was used and in addition to these, a biologically inert cement was used to obliterate the marrow cavities at the osteotomy sites. Finally, group D (control) included animals in which the gap was left without fixation and periosteum was completely removed.

Specimens were harvested at 8 weeks and were evaluated macroscopically, radiologically and histopathologically.

Data was analyzed using Fisher’s exact test and non-parametric statistics.

Results of this study showed that all gaps created in group A and 10 in 11 in group C demonstrated complete bone formation, bridging the entire defect. No traces of bone formation were observed in groups B and D.

These results indicate that rib periosteum has extremely high osteogenic capacity and can bridge large defects in vivo under the following conditions: a) its vascular supply is preserved and b) rigid fixation and functional loading is applied.