Trabecular structure and composition analysis of human autogenous bone donor sites using micro-computed tomography.

OBJECTIVES: To evaluate the bone microstructure of autogenous graft bone in elderly people (mean age, 66 years), we compared the bone volume/total volume and bone mineral density of four donor sites that are commonly harvested for maxillofacial surgery and dental implant treatments, using X-ray micro-computed tomography. METHODS: Eighteen Japanese cadavers were included in this study. Overall, 66 harvested bones (mandibular symphysis, mandibular ramus, ilium, and tibia) were studied. Micro-computed tomography scans of four sites were performed to analyze the trabecular structures, bone mineral density, and bone volume/total volume in these bones. RESULTS: The mandibular symphysis bones showed the highest bone volume/total volume and bone mineral density at the four sites. There was a significant difference in the bone volume/total volume between the mandibular symphysis and tibia groups. There was also a significant difference in bone mineral density between the mandibular symphysis group and the ilium and tibia groups. In the three-dimensional observations, the structures of the mandibular trabecular were plate-type. The structures of the tibial bone were mixtures of plate- and rod-types. In the ilium, most trabecula were rod-shaped. CONCLUSIONS: Mandibular symphysis and ramus had a higher bone volume/total volume and bone mineral density of the four sites and did not show regressive changes in our findings. Mandibular bone is the most suitable source of autogenous graft bone material because of its superior bone quality and quantity.

Resorption analysis of deproteinized cancellous bovine bone.

Commercially available deproteinized cancellous bovine bone (DPBB) has been indicated as non-absorbable bone filling materials. Stoichiometric hydroxyapatite (HA) was not resorbed by osteoclasts while calcium-deficient and carbonate-rich apatite converted from octacalcium (OCP hydrolysate) was resorbed by osteoclasts. We analyzed the chemical composition of DPBB and compared the tissue reactions around two materials after implanting into mouse bone marrow. X-ray diffraction analysis and Fourier transform infrared spectroscopy showed that DPBB was a carbonate-rich apatite. Micro-CT analysis indicated the massive bone formation on both materials at 2 weeks, then gradually resorbed. At 12 weeks, osteoclasts were directly attached to both materials. The ultrastructure of ruffled borders on DPBB was identical to osteoclasts resorbing normal bone while ruffled border on OCP hydrolysate showed irregular shape. These results indicated that DPBB was the absorbed material and that the structure of ruffled border of osteoclasts might be regulated by the size or orientation of HA.

Clinical study of octacalcium phosphate and collagen composite in oral and maxillofacial surgery.

Octacalcium phosphate and its collagen composite have been recognized as bone substitute materials possessing osteoconductivity and biodegradation properties. We evaluated the effectiveness of octacalcium phosphate and its collagen composite used for bone augmentation in major oral and maxillofacial surgeries in a clinical trial. Octacalcium phosphate and its collagen composite were used in cases of sinus floor elevation in 1- and 2-stage, socket preservation, cyst, and alveolar cleft procedures. A total of 60 patients were evaluated for effectiveness after the implantation of octacalcium phosphate and its collagen composite. Although sinus floor elevation in 1-stage, cyst, and alveolar cleft cases met the criteria for the judgment of success, sinus floor elevation in 2-stage and socket preservation groups did not meet the criteria in the initial evaluation. However, an additional evaluation for reconfirmation revealed the effectiveness of octacalcium phosphate and its collagen composite in those groups, and all evaluation results ultimately indicated the success of this clinical trial. Therefore, this clinical trial suggested that application of octacalcium phosphate and its collagen composite for oral and maxillofacial surgery was safe and effective and that octacalcium phosphate and its collagen composite could be a bone substitute candidate instead of autologous bone.

Use of a trephine bur and curette for minimally invasive harvesting of particulate cancellous bone and marrow from the iliac crest: a case of alveolar ridge reconstruction.

Iliac particulate cancellous bone and marrow (PCBM) is still the most predictable autogenous graft material for vertical ridge reconstruction because of its high cell content as well as osteoinductive and osteoconductive properties. However, postoperative meralgia paresthetica, gait disturbance, pain, and bleeding have been reported following conventional harvesting from the anterior iliac crest. We present a case of minimally invasive harvesting of iliac PCBM. A short incision was made, and the iliac crest was exposed after elevation of the periosteal membrane. Only the iliac cortical bone was removed using a trephine bur to avoid perforation. PCBM was harvested with hand curettes and grafted into the vertical ridge defect. Because of the small surgical field, gait disturbance was resolved within 1 day without other postoperative complications. This technique is potentially useful for harvesting a small amount of iliac PCBM.

Pituitary adenylate cyclase-activating polypeptide enhances saliva secretion via direct binding to PACAP receptors of major salivary glands in mice.

Xerostomia, or dry mouth, is a common syndrome that is generally treated with artificial saliva; however, no other effective methods have yet been established. Saliva secretion is mainly under the control of the autonomic nervous system. Pituitary adenylate cyclase-activating polypeptide (PACAP) is recognized as a multifunctional neuropeptide in various organs. In this study, we examined the effect of PACAP on saliva secretion, and detected the distribution of the PACAP type 1 receptor (PAC1R) in major salivary glands, including the parotid, submandibular, and sublingual glands, in 9-week-old male C57BL/6 mice. Intranasal administration of PACAP 38 increased the amount of saliva secreted, which was not inhibited by atropine pretreatment. Immunohistochemical analysis showed that PAC1R was distributed in the three major salivary glands. In the parotid and sublingual glands, PAC1R was detected in striated duct cells, whereas in the submandibular gland, a strong PAC1R immunoreaction was detected in tall columnar epithelial cells in the granular ducts (i.e., pillar cells), as well as in some striated duct cells. PACAP significantly increased the concentration of epidermal growth factor in saliva. These results suggest that PACAP directly regulates saliva secretion by controlling the absorption activity in the ducts, and that pillar cells regulate the function of granular epithelial cells in the granular duct, such as the secretion of growth factors into the saliva. Collectively, these results suggest the possibility of PACAP as a new effective treatment of xerostomia. Anat Rec, 299:1293-1299, 2016. © 2016 Wiley Periodicals, Inc.

Mandibular reconstruction using custom-made titanium mesh tray and particulate cancellous bone and marrow harvested from bilateral posterior ilia.

The objective of this study is to evaluate usefulness of mandibular reconstructions using a custom-made titanium mesh (Ti-mesh) tray and particulate cancellous bone and marrow (PCBM). A consecutive nine patients who underwent mandibular reconstruction were enrolled in this study. They were five men and four women (mean age: 53.9 years). Virtual reality simulation was performed using computer software based on the pre-operative computed tomography data. A 3-dimensional (3-D) skull model was constructed using a 3-D printer. A tray was custom-made from a Ti-mesh sheet bent to adapt to the model. After PCBM harvesting from bilateral posterior ilia, the tray was fixed to the host bone. New bone formation and configuration of the reconstructed mandible were assessed radiologically. Complications were recorded in each patient during the follow-up period. Patients, satisfaction with post-operative facial contour was evaluated using a visual analogue scale (VAS score, range = 0-100). In six of nine patients, excellent new bone formation was recognised and expected results were radiologically achieved. Complications occurred in four patients. These complications included Ti-mesh fracture, Ti-mesh exposure in the oral cavity, and delayed infection. Mean VAS score on patient satisfaction was 77.6. Although the data are preliminary, the results suggest that this method is clinically useful.

Solitary fibrous tumor of the buccal space resected in combination with coronoidectomy.

Solitary fibrous tumor (SFT) is an uncommon spindle-cell mesenchymal tumor of probable fibroblastic derivation that most often occurs in the pleura, where it is typically benign. This report describes a case of a large SFT that arose in the buccal space, and includes computerized tomography, magnetic resonance imaging, and positron emission tomography (PET) findings. (18)F-Fluorodeoxyglucose (FDG) PET axial imaging showed weak abnormal accumulation of FDG in the left buccal region. The tumor was located behind the posterior wall of the maxilla, adjacent to the medial aspect of the coronoid process and was compressed between the coronoid and maxillary alveolar processes. We resected it with the use of a transoral approach in combination with coronoidectomy. Coronoidectomy was chosen because it facilitated safe removal of the tumor by improving its visibility and providing enough working space to resect it through a transoral approach.