Clinical, Histological, and Scintigraphic Comparative Study of the Use of Mandibular Bone Marrow and Peripheral Blood in Bone Neoformation

Background and Purpose. To evaluate the capacity of mandibular bone marrow blood aspirate associated with biomaterials to stimulate bone tissue neoformation compared to the use of peripheral blood aspirate in patients with bone loss in the premaxillary region. Materials and Methods. The study included 16 patients with maxillary atresia. The region was grafted with xenograft blocks associated with the following treatments: G1, the patient’s peripheral blood during surgery, and G2, dripping of mandibular bone marrow blood until the xenograft was completely wet. After 7 and 14 days, scintigraphic images of the regions of interest (ROI) were taken to quantify pixels, which indicate osteogenic activity. Additionally, trephined samples obtained at the time of implant placement were stained in H&E, and newly formed bone tissue was quantified. The data were tabulated and statistically analyzed at a significance level of 5%. Results. Scintigraphic data showed greater osteogenic activity with mandibular bone marrow blood (G2) at all times evaluated p < 0.05 . As for the histomorphometric analysis, a greater amount of bone tissue was observed in samples treated with mandibular bone marrow blood (G2) compared to peripheral blood (G1) p < 0.05 . Conclusions. The appositional bone reconstruction technique in the block associated with mandibular bone marrow blood increased bone neoformation and osteogenic activity compared to conventional graft treatment with peripheral blood.

Use of Micro-CT Imaging to Assess Ventral Mandibular Cortical Thickness and Volume in an Experimental Rodent Model With Chronic High-Phosphorus Intake

Adverse effects of high dietary phosphorus on bone health have been observed in both animal and human studies. The aim of the investigation was to examine chronic effects of high phosphorus diet on the apical mandibular cortical thickness and volume in a hystricomorph rodent (Octodon degus) using microcomputed tomography. Male degus were randomly divided into two groups fed by different mineral contents from the age of 12 weeks till the age of 17 months. The micro-CT scanning and wall thickness analysis were applied on the region of the mandible exactly under the apices of the 4th premolar tooth, first molar tooth, and second molar tooth in two animals from each group. General overview and mapping of the ventral mandibular bone thickness revealed pronounced bony mandibular protrusions in all the animals fed a high-phosphorus diet with obvious bone thinning apically to the 4th premolar and first and second molar tooth apices. Mandibular bone volume and thickness located apically to the premolar and molars were statistically significantly smaller/thinner in the group fed by a high phosphorus diet. The thinnest bone measured 0.004 mm, where the mandibular 4th premolar tooth almost perforated the mandibular cortex. Similar studies of metabolic bone disease and its influence on alveolar bone were also published in rats and mice. The influence of different environmental, infectious, or metabolic factors on the growing tooth, alveolar bone formation, and bone pathologies must be done experimentally on growing animals. In contrast, degus have continuously growing dentition, and the effect of any of the above listed factors can be studied in this animal model at any age and for longer time periods.

Static Magnetic Fields Enhance the Chondrogenesis of Mandibular Bone Marrow Mesenchymal Stem Cells in Coculture Systems

Objectives. Combining the advantages of static magnetic fields (SMF) and coculture systems, we investigated the effect of moderate-intensity SMF on the chondrogenesis and proliferation of mandibular bone marrow mesenchymal stem cells (MBMSCs) in the MBMSC/mandibular condylar chondrocyte (MCC) coculture system. The main aim of the present study was to provide an experimental basis for obtaining better cartilage tissue engineering seed cells for the effective repair of condylar cartilage defects in clinical practice. Methods. MBMSCs and MCCs were isolated from SD (Sprague Dawley) rats. Flow cytometry, three-lineage differentiation, colony-forming assays, immunocytochemistry, and toluidine blue staining were used for the identification of MBMSCs and MCCs. MBMSCs and MCCs were seeded into the lower and upper Transwell chambers, respectively, at a ratio of 1 : 2, and exposed to a 280 mT SMF. MBMSCs were harvested after 3, 7, or 14 days for analysis. CCK-8 was used to detect cell proliferation, Alcian blue staining was utilized to evaluate glycosaminoglycan (GAG), and western blotting and real-time quantitative polymerase chain reaction (RT-qPCR) detected protein and gene expression levels of SOX9, Col2A1 (Collagen Type II Alpha 1), and Aggrecan (ACAN). Results. The proliferation of MBMSCs was significantly enhanced in the experimental group with MBMSCs cocultured with MCCs under SMF stimulation relative to controls ( P < 0.05 ). GAG content was increased, and SOX9, Col2A1, and ACAN were also increased at the mRNA and protein levels ( P < 0.05 ). Conclusions. Moderate-intensity SMF improved the chondrogenesis and proliferation of MBMSCs in the coculture system, and it might be a promising approach to repair condylar cartilage defects in the clinical setting.

Usefulness of a Nanostructured Fibrin-Agarose Bone Substitute in a Model of Severely Critical Mandible Bone Defect

Critical defects of the mandibular bone are very difficult to manage with currently available materials and technology. In the present work, we generated acellular and cellular substitutes for human bone by tissue engineering using nanostructured fibrin–agarose biomaterials, with and without adipose-tissue-derived mesenchymal stem cells differentiated to the osteogenic lineage using inductive media. Then, these substitutes were evaluated in an immunodeficient animal model of severely critical mandibular bone damage in order to assess the potential of the bioartificial tissues to enable bone regeneration. The results showed that the use of a cellular bone substitute was associated with a morpho-functional improvement of maxillofacial structures as compared to negative controls. Analysis of the defect site showed that none of the study groups fully succeeded in generating dense bone tissue at the regeneration area. However, the use of a cellular substitute was able to improve the density of the regenerated tissue (as determined via CT radiodensity) and form isolated islands of bone and cartilage. Histologically, the regenerated bone islands were comparable to control bone for alizarin red and versican staining, and superior to control bone for toluidine blue and osteocalcin in animals grafted with the cellular substitute. Although these results are preliminary, cellular fibrin–agarose bone substitutes show preliminary signs of usefulness in this animal model of severely critical mandibular bone defect.

COMPLICATIONS OF RECONSTRUCTION PLATE INSTALLATION IN MANDIBULAR

Background: Mandibular resection will cause mandibular stability disturbance due to loss of some part of the bone. Instability of the mandible can cause aesthetic, physiological, and psychological malfunction. Installment of mandibular reconstruction plat on the remaining mandibular using screws were suggested to restore its stability. However, it is not uncommon that plat exposure occurs following mandibular reconstruction, caused by inaccurate adaptation of the plats to the mandibular bone. The aims of this report are to describe the various complications and managements after jaw resection and reconstruction with plates. Case Report: A 44 years old male patient complained the small defect in the chin, painless, and no fluid emited, accompanied by dermatitis. Intra oral examination showed no abnormalities. About 1 year ago the patient performed segmental resection of the mandible on the indication of ameloblastoma. The radiological x-ray showed all screw detached from the plat and radiolucent images appeared around the plat that attached to the mandible. The diagnosis was fistula at regio mentale, post resection and reconstruction surgery, suspected caused by titanium plate allergies. The provided therapies were fistulectomy, screw removal, and plate reconstruction. Post therapy conditions showed improvement and no patients complaints of pain. Conclusion: Plate exposure is a complication that can occur after the installation of the reconstruction plate, but besides that it can also cause an allergic reaction from the material used. Keywords: Complication, Mandibular Resection, Plate Reconstruction, Titanium Plate Allergies

A New Orthodontic-Surgical Approach to Mandibular Retrognathia

(1) Background: Mandibular deficiency is one of the most common growth disorders of the facial skeleton. Recently, distraction osteogenesis has been suggested as the treatment of choice for overcoming the limitations of conventional orthognathic surgery; (2) Methods: A new custom-manufactured dental-anchored distractor was built and anchored in the first molar and lower canine. It consists of a stainless-steel disjunction screw, adapted and welded to the orthodontic bands through two 1.2 mm diameter connector bars with a universal silver-based and cadmium-free solder; (3) Results: The distractor described can be a useful tool to correct mandibular retrognathia and is better tolerated by patients, especially in severe cases; (4) Conclusions: The dental-anchored distractor increases the anterior mandibular bone segment without affecting the gonial angle or transverse angulation of the segments and avoids posterior mandibular rotation, overcoming the limitations of conventional surgical treatment.