Björn Möller

The cytotoxic effects of three different bisphosphonates in-vitro on human gingival fibroblasts, osteoblasts and osteogenic sarcoma cells

INTRODUCTION Osteonecrosis of the jaw (ONJ) is an emerging condition in patients undergoing long-term administration of bisphosphonates (BP) for the treatment of osteoporosis and hypercalcaemia associated with malignancy, multiple myeloma, and metastatic breast and prostate cancers. This is a follow-up study, its purpose was to examine the effects in-vitro of intravenous zoledronic acid (ZOL) and pamidronate (PAM) and oral alendronate (FOS) on the human oral cavity using gingival fibroblasts and osteoblasts cells and, in addition, osteogenic sarcoma cells (SaOS-2-cells). MATERIALS AND METHODS Human gingival fibroblasts, osteoblasts and SaOS-2-cells were seeded on multiple 6-well plates at a density of 5 × 10(5)cells in a 4-week cell culture. Four different concentrations (1, 5, 10, 20 μM) of each BP (ZOL, PAM, FOS) and pyrophosphate were used in this study. RESULTS All BP decreased collagen production and lowered cell proliferation in-vitro. ZOL was the component with most inhibitory effect. CONCLUSION The findings in this study suggest that ZOL, PAM and FOS generally diminish cell proliferation and collagen production of human gingival fibroblasts, osteoblasts and SaOS-2-cells. The present follow-up study shows that not only ZOL and PAM but also FOS have a strong inhibitory effect on collagen production and cell survival in-vitro.

Tissue Engineering of a Vascularized Bone Graft of Critical Size with an Osteogenic and Angiogenic Factor-Based In Vivo Bioreactor

Engineering a large vascularized bone graft is a much greater challenge than engineering small bone tissues. Although this is essentially feasible through an osteogenic factor-based in vivo bioreactor technique, the ossification needs improving. This study was aimed to investigate the possibility and efficacy of ectopic cultivation of sizeable bone grafts with large angiogenic and osteogenic factor-loaded natural bovine bone mineral (NBBM) scaffolds. For this purpose, six groups of sizeable composite scaffolds were constructed, consisting of a titanium mesh cage of NBBM or a mixture of NBBM/autogenous bone particles (AB), which were preloaded with 660 μg recombinant human bone morphogenetic protein-7 (rhBMP-7) and/or 4 μg recombinant human vascular endothelial growth factor165 (rhVEGF165). The scaffolds were implanted in bilateral latissimus dorsi muscles in eight pigs to construct in vivo bioreactors. Sequential fluorescence labeling was then applied to trace bone formation at the early stage. The implan...

Comparison of collagen membranes and polydioxanone for reconstruction of the orbital floor after fractures.

Orbital floor fractures, often combined with zygomatic fractures, are common fractures of the midface. Surgery of orbital fractures is done to free incarcerated or prolapsed orbital tissue and to restore the anatomic skeletal size of the orbit. Lyodura was a standard for the reconstruction of the orbital floor until cases of Creutzfeldt-Jakob disease were reported, so that polydioxanone (PDS) is widely used today. However, infections around the implant are reported. In a randomized controlled clinical study on 24 patients with orbital floor defects of approximately 1 cm2, we evaluated the use of a collagen membrane compared with a PDS foil. Computed tomography controls and ophthalmologic examinations were performed after 6 months in 10 patients per group. Intraoperative complications occurred neither in the collagen membrane group nor in the PDS group. In case of orbital rim fractures, the collagen membrane could additionally cover these defects. Perioperatively and postoperatively, no complications such as infections were observed. After 6 months, computed tomography controls revealed a complete reposition of orbital tissue and even bone regeneration in both groups. Diplopia and hypoesthesia were completely reversed after half a year. Smaller defects (up to 1 cm2) of the orbital floor can be restored with a PDS foil or a collagen membrane. However, for larger defects, stability may not be sufficient.

Forces affecting orbital floor reconstruction materials – A cadaver study

INTRODUCTION The objectives of this study were: (i) to evaluate the applied force and the displacement of the orbital contents after orbital floor reconstruction using artificially aged reconstruction materials in fresh frozen human heads and (ii) to analyze the puncture strength of the materials. MATERIAL AND METHODS Six fresh frozen human heads were used, and orbital floor defects in the right and left orbit were created by 3.0 J direct impacts on the globe and infraorbital rim. The orbital floor defect sizes and displacements were evaluated after a Le-Fort-I osteotomy. RESULTS The orbital floor defect sizes were 208.3(SD, 33.4) mm(2) for the globe impacts and 221.8(SD, 53.1) mm(2) for the infraorbital impacts. The forces on the incorporated materials were approximately 0.003 N and 0.03 N for the PDS-foil and collagen membrane, respectively. The displacements of the materials were +0.9 mm and +0.7 mm for the PDS-foil and collagen membrane, respectively. The puncture strengths of the PDS-foil and collagen membrane decreased from approximately 70 N and 12 N at week 1 to approximately 5 N and 1.5 N at week 8 of artificial aging. CONCLUSION The force applied to the orbital content is minimal, and the puncture strengths of the artificially aged materials are more than sufficient for the measured forces.

Maximum forces applied to the orbital floor after fractures.

Abstract The objective of this study was to measure the force on and displacement of completely detached intraorbital tissue from thebony orbit, as a worst-case scenario after orbital trauma, to preserve the maximum load and predict the necessary strength of reconstruction materials. Six fresh-frozen human heads were used, and orbital floor defects in the right and left orbits were created by the direct impact of 3.0 J onto the globe and infraorbital rim. The orbital floor defect sizes and displacements were evaluated after performing a Le Fort I osteotomy. In addition, after the repositioning of the completely detached intraorbital tissue, the forces and displacements were measured. The mean orbital floor defect sizes were 208.3 (SD, 33.4) mm2 for globe impacts and 221.8 (SD, 53.1) mm2 for infraorbital impacts. The mean intraorbital tissue displacement after the impact and before repositioning was 5.6 (SD, 1.0) mm for globe impacts and 2.8 (SD, 0.7) mm for infraorbital impacts. After repositioning, the displacements were 0.8 (SD, 0.5) mm and 1.1 (SD, 0.7) mm, respectively. The measured forces were 0.10519 (SD, 0.00958) N without the incorporation and approximately 0.11128 (SD, 0.003599) N with the incorporation of reconstruction materials. The maximum forces on the completely detached orbital tissue were minimal (∼0.11 N) and suggest the use of collagen membranes as reconstruction materials for orbital floor defects, at least in medium-sized fractures.

Extensive aneurysmal bone cyst of the mandible.

The aneurysmal bone cyst (ABC) is a rare benign lesion with an incidence of approximately 1% to 2% of bone tumors mainly in patients of 10 to 20 years of age and requires an operative procedure involving complete removal. We present a rare case of a large ABC in the angle and ramus of the mandible of a 14-year-old boy. The lesion had first been seen by a pediatrician 3 months before and turned out to be causing both a large and rapidly increasing swelling of the right face. Histology revealed a solid ABC, located in the angle and ramus of the mandible with cortical perforation and extrusion of the neighboring structures. A segmental resection of the mandible and soft-tissue excision of the lesion was performed. The mandible was primarily reconstructed by microvascular free-fibula transfer. The ABC did not show specific clinical or radiologic signs based on varying clinical examinations. The diagnosis was thus challenging, and other malignant tumors that can occur in the maxillofacial field had to be considered. Aneurysmal bone cysts mainly occur in patients 10 to 20 years old, so it is of clinical significance for pediatricians and pediatric dentists, who may well be the first to see such patients. This case report shows an ABC unusual in both its clinical findings and the therapy necessary. This article gives a conclusive review of diagnosis, pathogenesis, and treatment options.

Facial self-perception, well-being, and aesthetic surgery.

Background It is controversial whether impaired well-being is associated with (a) an increased likelihood of having a negative body/facial image; or (b) dissatisfaction with the postoperative result following aesthetic surgery. We set out to improve current knowledge in this matter. Methods A total of 324 subjects (n = 162 females, n = 162 males, 18–30 years) were photographed, asked to complete the adjective mood scale and to rate 46 statements regarding their own appearance, and its impact on social functioning as well as their willingness to undergo aesthetic surgery on a visual analog scale. The photographs of these subjects were also assessed by 50 independent judges. Results Average self-awarded ratings of appearance were significantly more positive in subjects with normal as compared to those with impaired well-being (P = 0.014). Items regarding the impact of appearance on social functioning were answered significantly more negatively by subjects with impaired well-being as compared with those with the normal well-being (P = 0.001). Subjects with impaired well-being did not declare an increased willingness to undergo aesthetic surgery (P > 0.197). Assessment by the independent judges did not reveal differences in the average level of attractiveness of subjects with impaired well-being and those with normal well-being (P = 0.666). Conclusions Impaired well-being is associated with impaired facial selfperception, independent of attractiveness. Willingness to undergo aesthetic surgery seems not to be affected by one’s sense of well-being. In the subjects with impaired well-being who undergo aesthetic surgery, facial self-perception seems unlikely to be improved.

Highly porous hydroxyapatite with and without local harvested bone in sinus floor augmentation: a histometric study in pigs

OBJECTIVE Sinus floor augmentation with autologous bone is an accepted treatment option in dental implantology. In this study, an entirely synthetic, nano-structured, hydroxyapatite-based bone substitute material (SBSM, NanoBone(®); Artoss, Rostock, Germany) was supplemented with a mixture of locally harvested bone to enhance osteogenesis. METHODS Bilateral sinus augmentation procedures were performed in eight domestic pigs using the lateral window technique. On the right side (control), 2.6 ml of SBSM was used, and on the left side (test), 2.6 ml of SBSM with additional 15% (390 μl) autologous bone was used. At the time of augmentation, a titanium implant (ITI(®)) was inserted from a laterocaudal direction. After 3 months, the sites of augmentation were removed and examined in non-decalcified sections by microradiography and fluorescence microscopy of sequentially labelled specimens and histometry. RESULTS On both sides, a significant amount of newly formed bone was observed. However, a statistically significant difference in the bone-implant contact was observed in the control group (median, 28.9%) compared with the test side with the additional autologous bone (median, 40.6%) (P = 0.01). Different bone density was achieved from the coronal to apical surfaces (medians, 54.6%, 9.6%, and 27.5%) compared with the test side (medians, 55.2%, 40.6%, and 44.2%). The median of augmentation height was 8.6 mm on the control side and 11.5 mm on the test side (P = 0.01). Bone apposition was observed in both groups after 15 days. CONCLUSION The SBSM shows acceptable results in sinus floor augmentation. The additional use of locally harvested autologous bone enhances bone density and osseointegration of the implants.

Endocultivation of scaffolds with rhBMP 2 and VEGF165 in the omentum majus in a rabbit model

The reconstruction of defects in the mandible are still challenging. Despite several adequate microvascular bone reconstruction techniques, there is a need for ectopic bone endocultivation without drawbacks by donor-site morbidity. The omentum majus is described as a good vascularized fleece with undifferentiated cells with potential for bone culturing. In the omentum majus of six rabbits, two hydroxyapatite blocks were incorporated for 12 weeks each. The blocks were prepared with recombinant human bone morphogenetic protein-2 (rhBMP-2) or VEGF165 + rhBMP-2 and wrapped into the omentum. For ectopic bone endocultivation observation computed tomography (CT) scans were performed, and fluorescence markers were applied. After harvesting the block, histological sections were performed with hematoxylin and eosin and toluidine blue staining. In the CT scans, the Hounsfield units of the blocks increased within the trail. In some sections, new bone formation was observed within the hydroxyapatite blocks, however, the histological staining showed soft-tissue invasion only, no gross bone formation was observed. The ectopic bone endocultivation in the omentum majus is technically a good approach. An adequate mixture of osteoinductive proteins is still missing.