Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Prosthodontic Society  

PURPOSE: We examined blood and protein dynamics potentially influenced by implant threads and hydrophilic/hydrophobic states of implant surfaces. METHODS: A computational fluid dynamics model was created for a screw-shaped implant with a water contact angle of 70° (hydrophobic surface) and 0° (superhydrophilic surface). Movements and density of blood and fibrinogen as a representative wound healing protein were visualized and quantified during constant blood inflow. RESULTS: Blood plasma did not occupy 40-50% of the implant interface or the inside of threads around hydrophobic implants, whereas such blood voids were nearly completely eliminated around superhydrophilic implants. Whole blood field vectors were disorganized and random within hydrophobic threads but formed vortex nodes surrounded by stable blood streams along the superhydrophilic implant surface. The averaged vector within threads was away from the implant surface for the hydrophobic implant and towards the implant surface for the superhydrophilic implant. Rapid and massive whole blood influx into the thread zone was only seen for the superhydrophilic implant, whereas a line of conflicting vectors formed at the entrance of the thread area of the hydrophobic implant to prevent blood influx. The fibrinogen density was up to 20-times greater at the superhydrophilic implant interface than the hydrophobic one. Fibrinogen density was higher at the interface than outside the threads only for the superhydrophilic implant. CONCLUSIONS: Implant threads and surface hydrophilicity have profound effects on vector and distribution of blood and proteins. Critically, implant threads formed significant biological voids at the interface that were negated by superhydrophilicity-induced contact hemodynamics.

DOI： 10.2186/jpr.JPR_D_22_00225

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Vertical bone augmentation to create host bone prior to implant placement is one of the most challenging regenerative procedures. The objective of this study is to evaluate the capacity of a UV-photofunctionalized titanium microfiber scaffold to recruit osteoblasts, generate intra-scaffold bone, and integrate with host bone in a vertical augmentation model with unidirectional, limited blood supply. Scaffolds were fabricated by molding and sintering grade 1 commercially pure titanium microfibers (20 μm diameter) and treated with UVC light (200-280 nm wavelength) emitted from a low-pressure mercury lamp for 20 min immediately before experiments. The scaffolds had an even and dense fiber network with 87% porosity and 20-50 mm inter-fiber distance. Surface carbon reduced from 30% on untreated scaffold to 10% after UV treatment, which corresponded to hydro-repellent to superhydrophilic conversion. Vertical infiltration testing revealed that UV-treated scaffolds absorbed 4-, 14-, and 15-times more blood, water, and glycerol than untreated scaffolds, respectively. In vitro, four-times more osteoblasts attached to UV-treated scaffolds than untreated scaffolds three hours after seeding. On day 2, there were 70% more osteoblasts on UV-treated scaffolds. Fluorescent microscopy visualized confluent osteoblasts on UV-treated microfibers two days after seeding but sparse and separated cells on untreated microfibers. Alkaline phosphatase activity and osteocalcin gene expression were significantly greater in osteoblasts grown on UV-treated microfiber scaffolds. In an in vivo model of vertical augmentation on rat femoral cortical bone, the interfacial strength between innate cortical bone and UV-treated microfiber scaffold after two weeks of healing was double that observed between bone and untreated scaffold. Morphological and chemical analysis confirmed seamless integration of the innate cortical and regenerated bone within microfiber networks for UV-treated scaffolds. These results indicate synergy between titanium microfiber scaffolds and UV photofunctionalization to provide a novel and effective strategy for vertical bone augmentation.

DOI： 10.3390/cells12010019

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Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

Bone cement containing benzoyl peroxide (BPO) as a polymerization initiator are commonly used to fix orthopedic metal implants. However, toxic complications caused by bone cement are a clinically significant problem. Poly (methyl methacrylate) tri-n-butylborane (PMMA-TBB), a newly developed material containing TBB as a polymerization initiator, was found to be more biocompatible than conventional PMMA-BPO bone cements due to reduced free radical generation during polymerization. However, free radicals might not be the only determinant of cytotoxicity. Here, we evaluated the response and functional phenotypes of cells exposed to extracts derived from different bone cements. Bone cement extracts were prepared from two commercial PMMA-BPO cements and an experimental PMMA-TBB. Rat bone marrow-derived osteoblasts and osteoclasts were cultured in a medium supplemented with bone cement extracts. More osteoblasts survived and attached to the culture dish with PMMA-TBB extract than in the culture with PMMA-BPO extracts. Osteoblast proliferation and differentiation were higher in the culture with PMMA-TBB extract. The number of TRAP-positive multinucleated cells was significantly lower in the culture with PMMA-TBB extract. There was no difference in osteoclast-related gene expression in response to different bone cement extracts. In conclusion, PMMA-TBB extract was less toxic to osteoblasts than PMMA-BPO extracts. Although extracts from the different cement types did not affect osteoclast function, PMMA-TBB extract seemed to reduce osteoclastogenesis, a possible further advantage of PMMA-TBB cement. These implied that the reduced radical generation during polymerization is not the only determinant for the improved biocompatibility of PMMA-TBB and that the post-polymerization chemical elution may also be important.

DOI： 10.3390/cells11243999

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The transplantation of pre-vascularized bone grafts is a promising strategy to improve the efficacy of engraftment and bone regeneration. We propose a hydrogel microbead-based approach for preparing vascularized and high-density tissue grafts. Mesenchymal stem cell-encapsulated collagen microgels (2 µL), termed bone beads, were prepared through spontaneous constriction, which improved the density of the mesenchymal stem cells and collagen molecules by more than 15-fold from the initial day of culture. Constriction was attributed to cell-attractive forces and involved better osteogenic differentiation of mesenchymal stem cells than that of spheroids. This approach was scalable, and ∼2000 bone beads were prepared semi-automatically using a liquid dispenser and spinner flask. The mechanical stimuli in the spinner flask further improved the osteogenic differentiation of the mesenchymal stem cells in the bone beads compared with that in static culture. Vascular endothelial cells readily attach to and cover the surface of bone beads. The in vitro assembly of the endothelial cell-enveloped bone beads resulted in microchannel formation in the interspaces between the bone beads. Significant effects of endothelialization on in vivo bone regeneration were shown in rats with cranial bone defects. The use of endothelialized bone beads may be a scalable and robust approach for treating large bone defects. STATEMENT OF SIGNIFICANCE: A unique aspect of this study is that the hMSC-encapsulated collagen microgels were prepared through spontaneous constriction, leading to the enrichment of collagen and cell density. This constriction resulted in favorable microenvironments for the osteogenic differentiation of hMSCs, which is superior to conventional spheroid culture. The microgel beads were then enveloped with vascular endothelial cells and assembled to fabricate a tissue graft with vasculature in the interspaces among the beads. The significant effects of endothelialization on in vivo bone regeneration were clearly demonstrated in rats with cranial bone defects. We believe that microgel beads covered with vascular endothelial cells provide a promising approach for engineering better tissue grafts for bone-regenerative medicine.

DOI： 10.1016/j.actbio.2022.08.044

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PURPOSE: A novel implant model consisting of meso-scale cactus-inspired spikes and nano-scale bone-inspired trabeculae was recently developed to optimize meso-scale roughness on zirconia. In this model, the meso-spike dimension had a significant impact on osteoblast function. To explore how different nano-textures impact this model, here we examined the effect of different nano-trabecula sizes on osteoblast function while maintaining the same meso-spike conformation. METHODS: Zirconia disks with meso-nano hybrid surfaces were created by laser etching. The meso-spikes were fixed to 40 μm high, whereas the nano-texture was etched as large and small trabeculae of average Feret diameter 237.0 and 134.1 nm, respectively. A polished surface was also prepared. Rat bone marrow-derived and human mesenchymal stromal cell-induced osteoblasts were cultured on these disks. RESULTS: Hybrid rough surfaces, regardless of nano-trabecula dimension, robustly promoted the osteoblastic differentiation of both rat and human osteoblasts compared to those on polished surfaces. Hybrid surfaces with small nano-trabeculae further enhanced osteoblastic differentiation compared with large nano-trabeculae. However, the difference in osteoblastic differentiation between small and large nano-trabeculae was much smaller than the difference between the polished and hybrid rough surfaces. The nano-trabecula size did not influence osteoblast attachment and proliferation, or protein adsorption. Both hybrid surfaces were hydro-repellent. The atomic percentage of surface carbon was lower on the hybrid surface with small nano-trabeculae. CONCLUSIONS: Small nano-trabeculae promoted osteoblastic differentiation more than large nano-trabeculae when combined with meso-scale spikes. However, the biological impact of different nano-trabeculae was relatively small compared with that of different dimensions of meso-spikes.

DOI： 10.2186/jpr.JPR_D_22_00015

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DOI： 10.1177/01455613221076784

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Titanium implants undergo temperature fluctuations during manufacturing, transport, and storage. However, it is unknown how this affects their bioactivity. Herein, we explored how storage (six months, dark conditions) and temperature fluctuations (5-50 °C) affected the bioactivity of titanium implants. Stored and fresh acid-etched titanium disks were exposed to different temperatures for 30 min under wet or dry conditions, and their hydrophilicity/hydrophobicity and bioactivity (using osteoblasts derived from rat bone marrow) were evaluated. Ultraviolet (UV) treatment was evaluated as a method of restoring the bioactivity. The fresh samples were superhydrophilic after holding at 5 or 25 °C under wet or dry conditions, and hydrophilic after holding at 50 °C. In contrast, all the stored samples were hydrophobic. For both fresh and stored samples, exposure to 5 or 50 °C reduced osteoblast attachment compared to holding at 25 °C under both wet and dry conditions. Regression analysis indicated that holding at 31 °C would maximize cell attachment (p < 0.05). After UV treatment, cell attachment was the same or better than that before temperature fluctuations. Overall, titanium surfaces may have lower bioactivity when the temperature fluctuates by ≥20 °C (particularly toward lower temperatures), independent of the hydrophilicity/hydrophobicity. UV treatment was effective in restoring the temperature-compromised bioactivity.

DOI： 10.3390/ma14195493

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Biomimetic design provides novel opportunities for enhancing and functionalizing biomaterials. Here we created a zirconia surface with cactus-inspired meso-scale spikes and bone-inspired nano-scale trabecular architecture and examined its biological activity in bone generation and integration. Crisscrossing laser etching successfully engraved 60 μm wide, cactus-inspired spikes on yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) with 200-300 nm trabecular bone-inspired interwoven structures on the entire surface. The height of the spikes was varied from 20 to 80 μm for optimization. Average roughness (Sa) increased from 0.10 μm (polished smooth surface) to 18.14 μm (80 μm-high spikes), while the surface area increased by up to 4.43 times. The measured dimensions of the spikes almost perfectly correlated with their estimated dimensions (R2 = 0.998). The dimensional error of forming the architecture was 1% as a coefficient of variation. Bone marrow-derived osteoblasts were cultured on a polished surface and on meso- and nano-scale hybrid textured surfaces with different spike heights. The osteoblastic differentiation was significantly promoted on the hybrid-textured surfaces compared with the polished surface, and among them the hybrid-textured surface with 40 μm-high spikes showed unparalleled performance. In vivo bone-implant integration also peaked when the hybrid-textured surface had 40 μm-high spikes. The relationships between the spike height and measures of osteoblast differentiation and the strength of bone and implant integration were non-linear. The controllable creation of meso- and nano-scale hybrid biomimetic surfaces established in this study may provide a novel technological platform and design strategy for future development of biomaterial surfaces to improve bone integration and regeneration.

DOI： 10.3390/ijms22157969

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

Polymethylmethacrylate (PMMA)-based acrylic bone cement is commonly used to fix bone and metallic implants in orthopedic procedures. The polymerization initiator tri-n-butylborane (TBB) has been reported to significantly reduce the cytotoxicity of PMMA-based bone cement compared to benzoyl peroxide (BPO). However, it is unknown whether this benefit is temporary or long-lasting, which is important to establish given that bone cement is expected to remain in situ permanently. Here, we compared the biocompatibility of PMMA-TBB and PMMA-BPO bone cements over several days. Rat femur-derived osteoblasts were seeded onto two commercially-available PMMA-BPO bone cements and experimental PMMA-TBB polymerized for one day, three days, or seven days. Significantly more cells attached to PMMA-TBB bone cement during the initial stages of culture than on both PMMA-BPO cements, regardless of the age of the materials. Proliferative activity and differentiation markers including alkaline phosphatase production, calcium deposition, and osteogenic gene expression were consistently and considerably higher in cells grown on PMMA-TBB than on PMMA-BPO, regardless of cement age. Although osteoblastic phenotypes were more favorable on older specimens for all three cement types, biocompatibility increased between three-day-old and seven-day-old PMMA-BPO specimens, and between one-day-old and three-day-old PMMA-TBB specimens. PMMA-BPO materials produced more free radicals than PMMA-TBB regardless of the age of the material. These data suggest that PMMA-TBB maintains superior biocompatibility over PMMA-BPO bone cements over prolonged periods of at least seven days post-polymerization. This superior biocompatibility can be ascribed to both low baseline cytotoxicity and a further rapid reduction in cytotoxicity, representing a new biological advantage of PMMA-TBB as a novel bone cement material.

DOI： 10.3390/ma14051289

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE INC  

Mucoceles originating in submandibular gland (SMG) which are extravasation type are extremely rare. Because the extraoral approach with potential risks of facial nerve injury and scar formation is commonly performed, we report endoscopically-assisted intraoral removal of submandibular gland mucocele as minimally invasive surgery. A 28-year-old female was referred to our department with an eight-week history of left submandibular painless swelling. Radiological diagnosis was not plunging ranula but SMG mucocele. The patient underwent endoscopically-assisted intraoral removal of SMG under general anesthesia as minimally invasive surgery. A mucosal incision on the left oral floor was made. After soft tissues surrounding the SMG were dissected bluntly, the mucocele and SMG were exposed more prominently by digital pressure applied beneath the lower border of the mandible by an assistant. The SMG was gripped with forceps after aspiration of mucocele, and pulled up through the incision by gland dissection. Because the facial artery penetrated the SMG, the facial artery was ligated and cut. The SMG with mucocele was removed completely in intraoral approach. Although there was no continuity with SMG and sublingual gland (SLG), the SLG was also removed preventively. The pathological diagnosis was SMG mucocele. Although lingual nerve paresthesia occurred postoperatively, the paresthesia was recovered completely 3 weeks after surgery. There was no recurrence 2.5 years after surgery. Because intraoral removal of SMG can be performed without cervical scar and facial nerve injury, this intraoral approach with endoscopic assistance can be an alternative to transcervical approach. (C) 2020 Asian AOMS, ASOMP, JSOP, JSOMS, JSOM, and JAMI. Published by Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.ajoms.2020.09.009

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Vascular anomalies in infants and children were separated into hemangiomas and vascular malformations based on their clinical appearance, histopathologic features, and biologic behavior. Whereas vascular malformations are structural abnormalities of capillary, arterial, venous, or lymphatic elements, vascular tumors are characterized by increased endothelial cell turnover. However, misdiagnoses and misperceptions persist around the use of the term hemangioma: Although venous malformations arising in the submandibular gland are extremely rare, the most have been diagnosed as "hemangioma". We report a rare submandibular gland venous malformation with multiple phleboliths. A 54-year-old female visited a private dental clinic for the pain of the right mandibular third molar. Panoramic radiograph showed multiple radiopaque lesions below the right mandibular angle. After the diagnosis of submandibular gland stones, she was referred to our department for the treatment. Ultrasonography showed a heterogeneous, hypoechoic lesion with multiple hyperechoic lesions and blood flow in the right submandibular gland. CT showed a well-circumscribed, heterogenous, low-density lesion with multiple calcifications in the right submandibular gland. MRI showed a lesion with signal intensity similar to that of the muscle in the right submandibular gland had multiple low signal intensity lesions on gadolinium-enhanced T1-weighted images. Radiological diagnosis was submandibular gland venous malformation with multiple phleboliths. She underwent intraoral removal of submandibular gland lesion under general anesthesia. Pathological diagnosis was submandibular gland venous malformation with multiple phleboliths. (C) 2020 Asian AOMS, ASOMP, JSOP, JSOMS, JSOM, and JAMI. Published by Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.ajoms.2020.10.006

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Frontiers Media SA  

Intracranial atherosclerotic disease (ICAD) has been characterized by the degree of arterial stenosis and downstream hypoperfusion, yet microscopic derangements of endothelial shear stress at the luminal wall may be key determinants of plaque growth, vascular remodeling and thrombosis that culminate in recurrent stroke. Platelet interactions have similarly been a principal focus of treatment, however, the mechanistic basis of anti-platelet strategies is largely extrapolated rather than directly investigated in ICAD. Platelet FcγRIIa expression has been identified as a potent risk factor in cardiovascular disease, as elevated expression markedly increases the risk of recurrent events. Differential activation of the platelet FcγRIIa receptor may also explain the variable response of individual patients to anti-platelet medications. We review existing data on endothelial shear stress and potential interactions with the platelet FcγRIIa receptor that may alter the evolving impact of ICAD, based on local pathophysiology at the site of arterial stenosis. Current methods for quantification of endothelial shear stress and platelet activation are described, including tools that may be readily adapted to the clinical realm for further understanding of ICAD.

DOI： 10.3389/fneur.2021.646309

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Language：English   Publisher：PREMCHAND SHANTIDEVI RESEARCH FOUNDATION  

DOI： 10.7860/JCDR/2021/45583.14487

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Actinomycotic osteomyelitis is an aggressive and persistent disease capable of invading and destroying bone, and chronic osteomyelitis with proliferative periostitis represents new bone formation with periosteal reaction. We report a rare case of actinomycotic osteomyelitis with proliferative periostitis arising in the mandibular ramus and spontaneous bone regeneration after coronoidectomy. A 14-year-old girl was referred for swelling in the right parotid-masseteric region and severe trismus. Contrast-enhanced CT revealed that heterogenous enhancement of the right masseter muscle, and a reactive bone formation over the lateral cortex of the right mandibular ramus and osteolysis of the condyle were seen in plain CT. MRI showed that the mandibular ramus was a low-signal intensity and the reactive bone on the ramus was signal intensity similar to muscle on T1-weighted images. The lesion was clinically and radiologically diagnosed as chronic osteomyelitis of the mandibular ramus. However, a biopsy was performed intraorally under general anesthesia to rule out a malignant bone tumor, and pathological examination showed fibrous bone and Actinomyces druses. Finally, the lesion was diagnosed as actinomycotic osteomyelitis with proliferative periostitis. She underwent image-guided intraoral removal of impacted right third molar and reactive proliferative bone on the right mandibular ramus under general anesthesia. To improve trismus, coronoidectomy also was performed. After the discharge, AMPC was administrated intraorally for 7.5 months. Postoperative panoramic radiograph and CT showed the right mandibular angle resorption and coronoid process regeneration. There was no recurrence of mandibular osteomyelitis 7 years after surgery.

DOI： 10.1007/s11282-020-00462-x

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DOI： 10.7860/JCDR/2020/45582.14313

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© 2020 Asian AOMS(+) ASOMP(+) JSOP(+) JSOMS(+) JSOM(+) and JAMI Conventional intraoral removal of deeply impacted or ectopic mandibular third molar is challenging for limited surgical access. Because there are potential risks of inferior alveolar nerve (IAN) injury or iatrogenic mandibular fracture, several methods for the removal have been proposed. As minimally invasive and safe surgery, we report image-guided removal of deeply impacted mandibular third molar using navigation system. A 32-year-old male was referred to our department with right mandibular pain and swelling. Panoramic radiograph showed right mandibular third molar was deeply impacted and interrupted the white line of the mandibular canal. Computed tomography (CT) showed deep impacted right mandibular third molar with root projection from the lingual cortical bone, and there was resorption of lingual cortical bone and passing of mandibular nerve between roots. For mandibular navigation surgery, a resin occlusal splint with titanium markers and handle was manufactured to fix reference frame to the mandible. CT was performed preoperatively after the occlusal splint was fixed with patient's mandibular teeth, and the patient underwent image-guided removal of mandibular third molar with navigation system under general anesthesia. After reference frame was attached to the handle of the occlusal splint fixed with patient's mandibular teeth, point-based registration was performed. The crown was removed after the sectioning, and the root sectioning with calibrated bur was performed carefully to avoid injury of the IAN under navigational guidance. The roots were completely removed, and the IAN was exposed in the lingual cortical bone defect. Postoperative course was uneventful without paresthesia of the IAN.

DOI： 10.1016/j.ajoms.2020.07.012

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

Superselective intra-arterial chemotherapy (SSIAC) for oral cancer can deliver a higher concentration of anticancer agent into a tumor-feeding artery than intravenous systemic chemotherapy. However, the agent distribution between the lingual artery and facial artery (FA) is not clear in SSIAC for patients with the linguofacial trunk. The agent distribution in the SSIAC method was investigated using computational fluid dynamics (CFD). Ten three-dimensional vessel models were created from CT images of two patients with oral cancer (patients A and B) with the linguofacial trunk. Catheter models were combined with vessel models to mimic intra-arterial infusion, and the agent flow was analyzed. In patient A models, the agent distribution varied depending on the catheter tip position in the linguofacial trunk, while all anticancer agents flowed into the FA only in patient B models. This study revealed that the behavior of the agent in the common trunk is determined by the blood flow field which depends on the topography of the vessels in each patient. Therefore, the catheter tip position should be changed according to the vessel topography to deliver anticancer agents into the tumor-feeding artery. Moreover, CFD can be a useful method to predict the agent flow for each patient before SSIAC.

DOI： 10.3390/app10217496

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With the increasing global popularity of Japanese delicacies made of raw seafood, such as sashimi and sushi, sufficient attention should be paid to the conditions caused by raw-food consumption. It is recognised that in ingesting raw squid, bacterial or planktonic toxin, and anisakid larva often cause food-poisoning and anisakiasis, respectively. Oral stings caused by sperm bag of squid are rare. A 21-year-old female had severe pain in her oral cavity immediately after eating a raw squid (Todarodes pacificus), and consulted the department of oral and maxillofacial surgery. Oral examination showed several small whitish, club-shaped foreign bodies stuck in the surface of the floor of mouth and left buccal mucosa. Because the removal with forceps was difficult due to the tight attachment to the mucosa, foreign bodies were removed completely using forceps with slight incisions under local anaesthesia. The stings were diagnosed as a sperm bag of squid.

DOI： 10.7860/JCDR/2020/45256.14074

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DOI： 10.1016/j.ajoms.2020.08.008

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DOI： 10.1177/0145561320940060

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Titanium materials are essential treatment modalities in the medical field and serve as a tissue engineering scaffold and coating material for medical devices. Thus, there is a significant demand to improve the bioactivity of titanium for therapeutic and experimental purposes. We showed that ultraviolet light (UV)-pre-treatment changed the protein-adsorption ability and subsequent osteoconductivity of titanium. Fibronectin (FN) adsorption on UV-treated titanium was 20% and 30% greater after 1-min and 1-h incubation, respectively, than that of control titanium. After 3-h incubation, FN adsorption on UV-treated titanium remained 30% higher than that on the control. Osteoblasts were cultured on titanium disks after 1-h FN adsorption with or without UV-pre-treatment and on titanium disks without FN adsorption. The number of attached osteoblasts during the early stage of culture was 80% greater on UV-treated and FN-adsorbed (UV/FN) titanium than on FN-adsorbed (FN) titanium; osteoblasts attachment on UV/FN titanium was 2.6- and 2.1-fold greater than that on control- and UV-treated titanium, respectively. The alkaline phosphatase activity of osteoblasts on UV/FN titanium was increased 1.8-, 1.8-, and 2.4-fold compared with that on FN-adsorbed, UV-treated, and control titanium, respectively. The UV/FN implants exhibited 25% and 150% greater in vivo biomechanical strength of bone integration than the FN- and control implants, respectively. Bone morphogenetic protein-2 (BMP-2) adsorption on UV-treated titanium was 4.5-fold greater than that on control titanium after 1-min incubation, resulting in a 4-fold increase in osteoblast attachment. Thus, UV-pre-treatment of titanium accelerated its protein adsorptivity and osteoconductivity, providing a novel strategy for enhancing its bioactivity.

DOI： 10.3390/ijms21124194

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Acrylic bone cement is widely used in orthopedic surgery for treating various conditions of the bone and joints. Bone cement consists of methyl methacrylate (MMA), polymethyl methacrylate (PMMA), and benzoyl peroxide (BPO), functioning as a liquid monomer, solid phase, and polymerization initiator, respectively. However, cell and tissue toxicity caused by bone cement has been a concern. This study aimed to determine the effect of tri-n-butyl borane (TBB) as an initiator on the biocompatibility of bone cement. Rat spine bone marrow-derived osteoblasts were cultured on two commercially available PMMA-BPO bone cements and a PMMA-TBB experimental material. After a 24-h incubation, more cells survived on PMMA-TBB than on PMMA-BPO. Cytomorphometry showed that the area of cell spread was greater on PMMA-TBB than on PMMA-BPO. Analysis of alkaline phosphatase activity, gene expression, and matrix mineralization showed that the osteoblastic differentiation was substantially advanced on the PMMA-TBB. Electron spin resonance (ESR) spectroscopy revealed that polymerization radical production within the PMMA-TBB was 1/15-1/20 of that within the PMMA-BPO. Thus, the use of TBB as an initiator, improved the biocompatibility and physicochemical properties of the PMMA-based material.

DOI： 10.3390/ijms21114016

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Titanium (Ti) is an osteoconductive material that is routinely used as a bulk implant to fix and restore bones and teeth. This study explored the effective use of Ti as a bone engineering scaffold. Challenges to overcome were: (1) difficult liquid/cell infiltration into Ti microfiber scaffolds due to the hydrophobic nature of Ti; and (2) difficult cell attachment on thin and curved Ti microfibers. A recent discovery of UV-photofunctionalization of Ti prompted us to examine its effect on Ti microfiber scaffolds. Scaffolds in disk form were made by weaving grade 4 pure Ti microfibers (125 µm diameter) and half of them were acid-etched to roughen the surface. Some of the scaffolds with original or acid-etched surfaces were further treated by UV light before cell culture. Ti microfiber scaffolds, regardless of the surface type, were hydrophobic and did not allow glycerol/water liquid to infiltrate, whereas, after UV treatment, the scaffolds became hydrophilic and immediately absorbed the liquid. Osteogenic cells from two different origins, derived from the femoral and mandibular bone marrow of rats, were cultured on the scaffolds. The number of cells attached to scaffolds during the early stage of culture within 24 h was 3-10 times greater when the scaffolds were treated with UV. The development of cytoplasmic projections and cytoskeletal, as well as the expression of focal adhesion protein, were exclusively observed on UV-treated scaffolds. Osteoblastic functional phenotypes, such as alkaline phosphatase activity and calcium mineralization, were 2-15 times greater on UV-treated scaffolds, with more pronounced enhancement on acid-etched scaffolds compared to that on the original scaffolds. These effects of UV treatment were associated with a significant reduction in atomic carbon on the Ti microfiber surfaces. In conclusion, UV treatment of Ti microfiber scaffolds tunes their physicochemical properties and effectively enhances the attachment and function of osteoblasts, proposing a new strategy for bone engineering.

DOI： 10.3390/ijms21030738

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Ultraviolet treatment of titanium implants makes their surfaces hydrophilic and enhances osseointegration. However, the mechanism is not fully understood. This study hypothesizes that the recruitment of fibrinogen, a critical molecule for blood clot formation and wound healing, is influenced by the degrees of hydrophilicity/hydrophobicity of the implant surfaces. Computational fluid dynamics (CFD) implant models were created for fluid flow simulation. The hydrophilicity level was expressed by the contact angle between the implant surface and blood plasma, ranging from 5° (superhydrophilic), 30° (hydrophilic) to 50° and 70° (hydrophobic), and 100° (hydrorepellent). The mass of fibrinogen flowing into the implant interfacial zone (fibrinogen infiltration) increased in a time dependent manner, with a steeper slope for surfaces with greater hydrophilicity. The mass of blood plasma absorbed into the interfacial zone (blood plasma infiltration) was also promoted by the hydrophilic surfaces but it was rapid and non-time-dependent. There was no linear correlation between the fibrinogen infiltration rate and the blood plasma infiltration rate. These results suggest that hydrophilic implant surfaces promote both fibrinogen and blood plasma infiltration to their interface. However, the infiltration of the two components were not proportional, implying a selectively enhanced recruitment of fibrinogen by hydrophilic implant surfaces.

DOI： 10.3390/ijms21020660

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Objective: Intra-oral minor salivary gland tumors are relatively rare. This study aimed to clarify the frequency and distribution of infra-oral minor salivary gland tumors in Japanese patients.Methods: We retrospectively analyzed the histopathological records of 131 patients with minor salivary gland tumors that were surgically treated between 1967 and 2017 at a single institution.Results: Of the 131 minor salivary gland tumors, 61 (47%) were benign and 70 (53%) were malignant. The male:female ratio was 1:1.8 for benign cases and 1:1 for malignant cases. Most of the tumors occurred in the palate, followed by the floor of the mouth. The most frequent minor salivary gland tumor was pleomorphic adenoma among benign tumors and adenoid cystic carcinoma among malignant tumors. The rarest minor salivary gland tumors were Warthin tumors and basal cell adenocarcinoma, accounting for only 0.8% of all cases.Conclusions: The present study determined the incidence rates of these rare tumors.

DOI： 10.1016/j.ajoms.2019.06.007

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier Ltd  

Osteomas are benign, slow-growing osteogenic tumors that consist of compact or cancellous bone. They sometimes arise from the craniomaxillofacial region. Among the peripheral, central, and extraskeletal types, peripheral osteomas arise from the periosteum, usually as unilateral, pedunculated, mushroom-like masses. Here, we report an unusual peripheral osteoma arising from the lateral surface of the mandibular ramus. A 57-year-old woman with a mass at the left mandibular ramus was referred to us. The hard and immobile mass had been growing for 15 years, and she had facial asymmetry. She had no trismus, temporomandibular joint dysfunction, previous facial trauma, or infection. Computed tomography showed a mushroom-like lesion (21.1 × 13.4 × 13.1 mm) arising from the lateral surface of the left mandibular ramus. Clinical diagnosis was peripheral osteoma. The lesion was removed using rotary instruments and a chisel through an intraoral approach under general anesthesia. The lesion had intruded into the masseter muscle. Pathological diagnosis was compact osteoma. The postoperative course was uneventful and there has been no recurrence 1.5 years after surgery.

DOI： 10.1016/j.ajoms.2018.02.004

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Scopus

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHURCHILL LIVINGSTONE  

The purpose of this study was to investigate the relationship between the pressure drop in the pharyngeal airway space (Delta P-PAS) and the minimum cross-sectional area (minCSA) of the pharyngeal airway before and after mandibular setback surgery using computational fluid dynamics, in order to prevent iatrogenic obstructive sleep apnoea. Eleven patients with mandibular prognathism underwent bilateral sagittal split osteotomy for mandibular setback. Three-dimensional models of the upper airway were reconstructed from preoperative and postoperative computed tomography images, and simulations were performed using computational fluid dynamics. Delta P-PAS and the minCSA of the pharyngeal airway were calculated, and the relationship between them was evaluated by non-linear regression analysis. In all cases, the minCSA was found at the level of the velopharynx. After surgery, Delta P-PAS increased significantly and the minCSA decreased significantly. The non-linear regression equation expressing the relationship between these variables was Delta P-PAS = 3.73 x minCSA(-2.06). When the minCSA was &lt;1 cm(2), Delta P-PAS increased greatly. The results of this study suggest that surgeons should consider bimaxillary orthognathic surgery rather than mandibular setback surgery to prevent the development of iatrogenic obstructive sleep apnoea when correcting a skeletal class III malocclusion.

DOI： 10.1016/j.ijom.2017.03.028

Web of Science

PubMed

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BIOMED CENTRAL LTD  

Background: Intra-arterial chemotherapy (IAC) for oral cancer can deliver a higher concentration of anticancer agent into a tumor-feeding artery than intravenous systemic chemotherapy. However, distribution of anticancer agent into several branches of the external carotid artery (ECA) in IAC has not demonstrated sufficient treatment efficacy. To improve the effectiveness of IAC, the flow distribution of anticancer agent into the branches of the ECA in several IAC methods was investigated using computational fluid dynamics (CFD).
Methods: Patient-specific three-dimensional vessel models were created from CT images of 2 patients with tongue cancer. Catheter models were combined with the vessel models. Thirty-two models were generated with varying vertical and horizontal positions of the catheter tip. With the use of a zero-dimensional resistance model of the peripheral vessel network, conventional IAC and superselective IAC were simulated in 30 and 2 models, respectively. The flow distribution of anticancer agent into the branches of the ECA was investigated in 32 models. Additionally, the blood streamline was traced from the inlet of the common carotid artery toward each outlet to examine the flow of anticancer agent in all models, and the wall shear stress of the vessel was calculated for some models.
Results: The CFD simulations could be conducted within a reasonable computational time. In several models, the anticancer agent flowed into the target artery only when the catheter tip was located below the bifurcation of the ECA and each target artery. Furthermore, the anticancer agent tended to flow into the target artery when the catheter tip was shifted toward the target artery. In all ECA branches that had flow of anticancer agent, the blood streamlines to the target arteries contacted the catheter tip. Anticancer agent flowed into only the target artery in patients' models for superselective IAC. However, high wall shear stress was observed at the target artery in one patient's model.
Conclusions: This CFD study showed that location of the catheter tip was important in controlling the anticancer agent in conventional IAC. The distribution rate of anticancer agent into the tumor-feeding artery tended to increase when the catheter tip was placed below and toward the target artery. Although superselective IAC can reliably supply anticancer agent to the target artery, high wall shear stress at the target artery can occur, depending on vessel geometry of the patient, which may cause serious complications during the treatment.

DOI： 10.1186/s12938-017-0348-5

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BIOMED CENTRAL LTD  

Background: Patient-specific modelling in clinical studies requires a realistic simulation to be performed within a reasonable computational time. The aim of this study was to develop simple but realistic outflow boundary conditions for patient-specific blood flow simulation which can be used to clarify the distribution of the anticancer agent in intra-arterial chemotherapy for oral cancer.
Methods: In this study, the boundary conditions are expressed as a zero dimension (0D) resistance model of the peripheral vessel network based on the fractal characteristics of branching arteries combined with knowledge of the circulatory system and the energy minimization principle. This resistance model was applied to four patient-specific blood flow simulations at the region where the common carotid artery bifurcates into the internal and external carotid arteries.
Results: Results of these simulations with the proposed boundary conditions were compared with the results of ultrasound measurements for the same patients. The pressure was found to be within the physiological range. The difference in velocity in the superficial temporal artery results in an error of 5.21 +/- 0.78 % between the numerical results and the measurement data.
Conclusions: The proposed outflow boundary conditions, therefore, constitute a simple resistance-based model and can be used for performing accurate simulations with commercial fluid dynamics software.

DOI： 10.1186/s12938-016-0133-x

Web of Science

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Language：English  

Cervicofacial subcutaneous emphysema is a rare complication of dental procedures. Although most cases of emphysema occur incidentally with the use of a high-speed air turbine handpiece, there have been some reports over the past decade of cases caused by dental laser treatment. Emphysema as a complication caused by the air cooling spray of a dental laser is not well known, even though dental lasers utilize compressed air just as air turbines and syringes do. In this study, we comprehensively reviewed cases of emphysema attributed to dental laser treatment that appeared in the literature between January 2001 and September 2012, and we included three such cases referred to us. Among 13 cases identified in total, nine had cervicofacial subcutaneous and mediastinal emphysema. Compared with past reviews, the incidence of mediastinal emphysema caused by dental laser treatment was higher than emphysema caused by dental procedure without dental laser use. Eight patients underwent CO2 laser treatment and two underwent Er:YAG laser treatment. Nine patients had emphysema following laser irradiation for soft tissue incision. Dentists and oral surgeons should be cognizant of the potential risk for iatrogenic emphysema caused by the air cooling spray during dental laser treatment and ensure proper usage of lasers.

DOI： 10.1111/adj.12119

PubMed

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Language：Japanese   Publisher：(一社)日本口腔診断学会  

症例は50歳代男性で、右側顎下部の腫脹が食事時に生じたため、近耳鼻咽喉科を受診した。右側顎下腺唾石症と診断され、顎下腺摘出術が必要と説明されたため、唾液腺内視鏡での低侵襲な治療を希望して当科受診となった。唾石は顎下腺腺体上部に存在していたため、内視鏡下での唾石摘出が困難であった場合には、内視鏡をガイドにした口内法で唾石の摘出を行い、それが困難であった場合には顎下腺摘出術が必要になることを患者に説明し、同意を得たうえで全身麻酔での手術を計画した。細い唾液腺内視鏡は腺体内まで挿入可能であり、主導管から2分岐目に唾石を確認できた。唾液腺内視鏡のワーキングチャンネルからバスケット鉗子を挿入し唾石を把持した。唾石が類円形であったこともあり、開口部を切開せずに摘出可能であった。術後2年3ヵ月経過するも顎下腺の腫脹や唾仙痛は認めず、経過良好である。

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Other Link： https://search-tp.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2018&ichushi_jid=J02383&link_issn=&doc_id=20181105220007&doc_link_id=10.15214%2Fjsodom.31.225&url=https%3A%2F%2Fdoi.org%2F10.15214%2Fjsodom.31.225&type=J-STAGE&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00007_2.gif

Language：Japanese   Publisher：(一社)日本口腔診断学会  

15歳男。顔面非対称を主訴とした。7歳時より左耳翼基部の膨隆を自覚し、2年前に生検にて線維性異形成症(FD)と診断されていた。口腔外所見では左鼻翼から鼻根部や頬部にかけて膨隆し、斜鼻を認めた。口腔内所見では左側上顎歯肉唇移行部から口唇粘膜にかけて骨の膨隆を認めた。CTでは左上顎洞を後方に圧排するように境界明瞭な充実性病変を認め、左鼻腔は閉塞していた。3D-CTでは左鼻骨、左上顎骨、左頬骨の膨隆を認めた。FDとしては典型的な画像所見ではなかったため生検を行ったところ、病理組織学的に骨形成線維腫(OF)またはFDの所見であった。画像所見と併せて考えOFと診断し、ナビゲーション手術を計画した。腫瘍を摘出した後、術前に行った健側をミラーリングした画像まで骨の削除を行い、手術を終了した。術直後の3D-CTでは左側上顎の膨隆していた骨が計画通りに削除されていることが確認できた。病理診断はOFであった。術後2年6ヵ月の現在、知覚異常はなく、左右対称の顔貌と左鼻腔の開存が得られている。

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Language：Japanese   Publisher：(一社)日本口腔診断学会  

70歳代女。右側顎下部の腫脹を主訴とした。CTで右側顎下腺の腺体中央部に3.1×2.8×2.6mmの唾石を認め、右側顎下腺腺体内唾石症と診断した。唾石は腺体中央部に存在していたが、大きさが約3mm程度であり、CT値が低いため粉砕が容易にできる可能性が高く、更に顎下腺移行部から唾石まで唾液の貯留が描出されていたことから、内視鏡手術が可能と判断した。受診当日に外来局所麻酔下に内視鏡下唾石摘出術を施行し、手術時間は35分と短く、術後経過は良好であった。術後1年4ヵ月の現在、再発は認めていない。

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Language：Japanese   Publisher：(一社)日本頭頸部癌学会  

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Language：Japanese   Publisher：(一社)日本口腔診断学会  

症例は10歳男児で、食事時の右側顎下部の腫脹を認めた。CTにて右側顎下腺唾石症と診断した。右側口底後方粘膜に自壊部を認めたが、排膿は認めなかった。嘔吐反射が強く口底部の触診は困難であった。右側舌下小丘部からの唾液の流出は認めなかった。CTでは右側顎下腺移行部に56×56×42mmの硬組織像を認めた。臨床所見から、急性化膿性顎下腺炎により口底粘膜から排膿ととともに唾石が排出された後に、自壊部から顎下腺移行部に生じた肉芽組織が導管を閉塞させていると考え、閉塞性顎下腺炎と診断した。抗菌薬による消炎を行い、唾液腺内視鏡による閉塞物の摘出術を計画した。全身麻酔下で内視鏡手術を行った。外来経過観察時の唾液の流出は良好となり、以後、顎下腺の腫脹は生じていない。

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Language：Japanese  

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J-GLOBAL

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Language：Japanese   Publisher：(一社)日本口腔腫瘍学会  

われわれは口腔癌患者の上部消化管領域における同時性重複癌のスクリーニングとしての上部消化管内視鏡検査(GIF)とFDG-PET/CTについて比較したので報告する。2006年9月から2009年8月までの3年間に口腔癌患者133例が治療前にGIFとFDG-PET/CTを受けた。GIFで5人の患者(3.8%)に食道や胃の同時性重複癌が発見され、それらは全例早期癌であった。しかし、FDG-PET/CTでは1人のみしか同時性重複癌(食道癌)が発見できず、その感度と特異度はそれぞれ20%と100%であった。本研究は口腔癌患者の上部消化管領域における治療前スクリーニングとしてのGIFの有用性と必要性を示した。(著者抄録)

DOI： 10.5843/jsot.26.31

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Other Link： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2014&ichushi_jid=J02382&link_issn=&doc_id=20140630260001&doc_link_id=%2Fdy8ortum%2F2014%2F002602%2F001%2F0031-0036%26dl%3D0&url=http%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fdy8ortum%2F2014%2F002602%2F001%2F0031-0036%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

DOI： 10.1299/jsmebio.2014.26.521

CiNii Books

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Event date： 2020.3

Language：English   Presentation type：Poster presentation  

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Event date： 2020.3

Language：English   Presentation type：Poster presentation  

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Event date： 2019.6

Language：English   Presentation type：Poster presentation  

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Event date： 2019.6

Language：English   Presentation type：Oral presentation (general)  

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Event date： 2019.6

Language：English   Presentation type：Poster presentation  

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Event date： 2019.1

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Event date： 2018.6

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Event date： 2018.1

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Event date： 2014.1

Language：Japanese  

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Event date： 2014.1

Language：Japanese  

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Language：Japanese   Presentation type：Symposium, workshop panel (nominated)  

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Language：English   Presentation type：Oral presentation (invited, special)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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