Cellular Response of Human Osteoblasts to Different Presentations of Deproteinized Bovine Bone.

Objectives: This study evaluated the cellular response of primary osteoblasts exposed to two different presentations of a low-temperature non-sintered deproteinized bovine bone matrix (DBBM). Materials and methods: Six different baths of a commercially available DBBM block (Bonefill® Porous Block) and one of DBBM granule (Bonefill® Porous) were evaluated to identify the mineral structure and organic or cellular remnants. Samples of the same baths were processed in TRIZOL for RNA extraction and quantification. For the immunologic cell reaction assay, primary human osteoblasts (pOB) were exposed to DBMM block (pOB + B) or granules (pOB + G), or none (control) for 1, 3, or 7 days of cell cultivation. Expression of proinflammatory cytokines by pOB was evaluated by crosslinked ELISA assay. In addition, total DNA amount, as well as cell viability via LDH evaluation, was assessed. Results: Organic remnants were present in DBBM blocks; 45.55% (±7.12) of osteocytes lacunae presented cellular remnants in blocks compared to 17.31% (±1.31) in granules. In three of five batches of blocks, it was possible to isolate bovine RNA. The highest concentration of TGF-ß1 was found in supernatants of pOB + G on day 7 (218.85 ± 234.62 pg/mL) (p < 0.05), whereas pOB + B presented the lowest amount of TGF-ß1 secretion at the end of evaluation (30.22 ± 14.94 pg/mL, p < 0.05). For IL-6 and OPG, there was no statistical difference between groups, while pOB + G induced more IL-8 secretion than the control (3.03 ± 3.38 ng/mL, p < 0.05). Considering the kinetics of cytokine release during the study period, all groups presented a similar pattern of cytokines, estimated as an increasing concentration for IL-6, IL-8, and OPG during cultivation. Adherent cells were observed on both material surfaces on day 7, according to H&E and OPN staining. Conclusion: Neither tested material induced a pronounced inflammatory response upon osteoblast cultivation. However, further studies are needed to elucidate the potential influence of organic remnants in bone substitute materials on the regeneration process.

Mandibular biomechanics after marginal resection: Correspondences of simulated volumetric strain and skeletal resorption.

Serious mandibular diseases such as tumor or osteonecrosis often require segmental or marginal mandibulectomy, the latter with improved outcome thanks to preserved mandibular continuity. Nevertheless, gradual osteolytic and/or osteosclerotic skeletal changes frequently indicate repetitive resections. Based on the fundamental adaptivity of bone to mechanical loads, the question arose whether resection-related anatomical alterations trigger relevant pathological skeletal adaptations. For a clinical case after mandibular box resection due to progressive osteoradionecrosis (ORN), routine biomechanical loading was simulated by finite element method, respecting pathology-related anatomy, tissue properties, and biting capacity. By 3D-visualization of the mandible's pathological development from follow-up-CT's over four years, remarkable correspondences of skeletal resorptions and increased unphysiological strain were revealed. Higher unphysiological load was correlated with more serious and earlier skeletal alterations. Three months post-operatively, serious buccal destruction at the distal resection corner occurred in correspondence with dominant tensile strain. At the resection, elevated strain caused by reduced alveolar height corresponded to skeletal compromise, observed 8-9 months post-operatively. ORN-related lesions, diagnosed before resection, entailed unphysiological strain coinciding with local skeletal alterations. Simulations with "healthy" instead of pathological tissue coefficients induced quantitative improvements of 25-33%, but without fundamental change. These results suggest a decisive contribution of resection-related biomechanical skeletal adaptations to this patient's mandibular decline with hemimandibulectomy about 2.5 years after the first resection. However, mechanical stress concentrations in sharp angles as the distal resection corner and reduced stability due to decreased alveolar height generally bear the danger of pathological biomechanics and severe skeletal adaptations for patients after mandibular box resection.

PTCH-1 and MDM2 expression in ameloblastoma from a West African sub-population: implication for chemotherapeutics.

INTRODUCTION: Ameloblastoma is a slow growing, painless odontogenic swelling which can attain sizes that result in severe deformities of the craniofacial complex. It is the most commonly encountered odontogenic tumor in Nigeria. Surgical intervention is currently the method of treatment; however identification of altered molecular pathways may inform chemotherapeutic potential. The Protein Patched homolog 1 (PTCH-1) is overexpressed in ameloblastoma. Also, mutation in the MDM2 gene can reduce the tumor suppressor function of p53 and promote ameloblastoma growth. No study however has characterized the molecular profile of African cases of ameloblastoma with a view to developing chemotherapeutic alternatives. The objective was to characterize the PTCH-1 genetic profile of Ameloblastoma in Nigerian patients as a first step in investigating its potential for chemotherapeutic intervention. METHODS: Twenty-eight FFPE blocks of ameloblastoma cases from Nigerian patients were prepared for antibody processing to PTCH-1 (Polyclonal Anti-PTCH antibody ab39266) and MDM2 (Monoclonal Anti-MDM2 antibody (2A10) ab16895). Cytoplasmic brown staining was considered as positive for PTCH while nuclear staining was positive for MDM2. RESULTS: Moderate and strong expressions for PTCH in ameloblast and stellate reticulum were 78.6% and 60.7% respectively. Only 3 (10.7%) cases expressed MDM2. CONCLUSION: The importance of our study is that it supports, in theory, anti-PTCH/SHH chemotherapeutics for Nigerian ameloblastoma cases and also infers the possible additional use of anti-p53 agents.

Computer-assisted analysis of human upper arm flexion by 4D-visualization based on MRI.

PURPOSE: 4D-visualization of the human upper arm based on sequential or dynamic MRI may be useful in functional orthopedic disorders and surgical planning. A cascade of 4D-visualization approaches have been applied including deformation of the soft tissue surfaces and muscular contraction. Skeletal structures and the epifascial tissue comprising vascular structures are included in the 4D-visualization. METHODS: Sequential MRI (T2-weighted spin echo sequences) scans of a healthy volunteer's upper extremity were obtained. The skeletal, muscular, and epifascial tissues were segmented. For 4D-rendering of the elbow joint, surface models of the humerus, the ulna, and the radius, were displaced with respect to the movement. For 4D-visualization of the soft tissue, the processed MRI data were subjected to highly transparent direct volume rendering with special two-tone transfer functions designed with regard to the application, e.g., muscular inner structure or fasciae. For rendering of time dependent behavior, the visualization was continuously updated. RESULTS: Continuous deformation of muscular inner structure and fasciae, and dynamics of muscle fibers could be differentiated in 4D-visualizations of the upper extremity. Using sequential MRI scans, this work was constrained by the high sagittal slice thickness and separation. CONCLUSION: 4D-visualization of the upper extremity based on sequential MRI is feasible and provides a realistic appearance in comparison with anatomical drawings and preparations. The 4D-visualization method may be useful for detecting and monitoring muscular pathologies and lesions.

Comparison of tooth- and bone-borne devices in surgically assisted rapid maxillary expansion by three-dimensional computed tomography monitoring: transverse dental and skeletal maxillary expansion, segmental inclination, dental tipping, and vestibular bone resorption.

Comparison of bone-borne (BB) versus tooth-borne (TB) distraction in surgically assisted rapid maxillary expansion, secondary variables were bipartite (2S) or tripartite (3S) osteotomy, pterygomaxillary osteotomy (+PP) or not (jPP), and age (920 years old [920] and G20 years old [G20]). Fifty patients received three-dimensional computed tomography examination preoperatively and after expansion; 24 had BB, and 26 had TB distraction. Predefined preoperative landmarks versus postexpansion positions were assessed in multiplanar viewing. Bone-borne devices had bigger overall skeletal and dental maxillary expansion declining from anterior to posterior, more asymmetric expansion, less vestibular bone resorption, and less dental tipping; TB devices showed similar dorsal decrease in transverse skeletal and dental maxillary expansion from anterior to posterior, more vestibular bone resorption, particularly in the premolars, and more dental tipping. Bone-borne 3S +PP G20 had the biggest decrease in transverse skeletal widening and biggest segmental outward inclination; BB 3S +PP 920 had the biggest decline in transverse dental widening; TB 2S YPP G20 had the biggest segmental inward inclination; BB 2S YPP 920 had the biggest dental tipping; BB 2S G20 had the biggest vestibular bone resorption in molars; and TB 3S 920 and BB YPP had the biggest vestibular bone resorption in premolars. There was a significant correlation between transverse widening and segmental inclination; that is, a bigger amount of transverse widening provokes less segmental inclination.