Masanori Masui

Biomechanical Loading Evaluation of Unsintered Hydroxyapatite/poly-l-lactide Plate System in Bilateral Sagittal Split Ramus Osteotomy

OSTEOTRANS MX® (Takiron Co., Ltd., Osaka, Japan) is a bioactive resorbable maxillofacial osteosynthetic material composed of an unsintered hydroxyapatite/poly-l-lactide composite, and its effective osteoconductive capacity has been previously documented. However, the mechanical strength of this plate system is unclear. Thus, the aim of this in vitro study was to assess its tensile and shear strength and evaluate the biomechanical intensity of different osteosynthesis plate designs after sagittal split ramus osteotomy by simulating masticatory forces in a clinical setting. For tensile and shear strength analyses, three mechanical strength measurement samples were prepared by fixing unsintered hydroxyapatite/poly-l-lactide composed plates to polycarbonate skeletal models. Regarding biomechanical loading evaluation, 12 mandibular replicas were used and divided into four groups for sagittal split ramus osteotomy fixation. Each sample was secured in a jig and subjected to vertical load on the first molar teeth. Regarding shear strength, the novel-shaped unsintered hydroxyapatite/poly-l-lactide plate had significantly high intensity. Upon biomechanical loading evaluation, this plate system also displayed significantly high stability in addition to bioactivity, with no observed plate fracture. Thus, we have clearly demonstrated the efficacy of this plate system using an in vitro model of bilateral sagittal split ramus osteotomy of the mandible.

Low-intensity pulsed ultrasound stimulation promotes osteoblast differentiation through hedgehog signaling

Low‐intensity pulsed ultrasound (LIPUS) has been used as an adjunct to fracture healing therapies, but the mechanisms underlying its action are not known. We reported that sonic hedgehog (SHH) signaling was activated in osteoblasts at the dynamic remodeling site of a bone fracture. Mechanical stimulation is a crucial factor in bone remodeling, and it is related to the primary cilia as a sensor of hedgehog signaling. Here we observed that LIPUS promoted callus formation in accord with Gli2‐positive cells after 14 days at the mouse femur fractured site compared with a control group. An immunofluorescence analysis showed that the numbers of primary cilia and cilia/osterix double‐positive osteoblasts were increased at the fracture site by LIPUS. LIPUS stimulated not only the number and the length of primary cilia, but also the levels of ciliated protein, Ift88 mRNA, and SHH, Gli1, and Gli2 in MC3T3‐E1 cells. Further experiments revealed that LIPUS stimulated osteogenic differentiation in the presence of smoothened agonist (SAG) treatment. These results indicate that LIPUS stimulates osteogenic differentiation and the maturation of osteoblasts by a primary cilium‐mediated activation of hedgehog signaling.

Use of an intraoperative navigation system and piezoelectric surgery for styloidectomy in a patient with Eagle’s syndrome: a case report

BackgroundElongated styloid process syndrome (Eagle’s syndrome) is the term given to the symptomatic elongation of the styloid process or the mineralization of the stylohyoid or stylomandibular ligament. The two commonly used approaches for the surgical treatment of this syndrome are the transcervical and transoral approaches. Both have their limitations and specific intraoperative risks. Here, we report the treatment of a patient with Eagle’s syndrome using the transoral approach in conjunction with piezoelectric surgery, surgical planning, and intraoperative navigation to reduce the risk of complications.Case presentationThe elongated styloid process was resected in a 45-year-old Japanese man using a minimally invasive approach with an intraoperative navigation system. Preoperative preparation involved the use of a custom interocclusal splint to produce the mouth opening conditions required during surgery. Using the three-dimensional position of the navigation probe, the location of the elongated styloid process was identified. After confirmation of the resection spot via the transoral approach, the styloid process was dissected by piezoelectric surgery. Follow-up examination showed an uneventful recovery with no associated complications.ConclusionThe resection of the styloid process using an intraoperative navigation system and a custom interocclusal splint during a transoral approach, together with a piezoelectric cutting device, is safe and effective for the treatment of Eagle’s syndrome.

Drug-induced hypersensitivity syndrome caused by carbamazepine used for the treatment of trigeminal neuralgia

An 88-year-old man was diagnosed with trigeminal neuralgia, and treatment of carbamazepine 200 mg/day was initiated. About 6 weeks later, the patient developed a skin rash accompanied by fever. He was admitted to hospital and diagnosed with drug-induced hypersensitivity syndrome (DIHS) caused by carbamazepine. Oral carbamazepine treatment was stopped, but blood tests showed acute liver and acute renal failure. Drug-induced lymphocyte stimulation test (DLST) for carbamazepine, human herpes virus-6 (HHV-6) IgG, and CMV-HRP were negative. Oral prednisolone therapy was begun 18 days later. The titer of HHV-6 IgG antibodies was then detected (640 times). Following treatment, liver and renal function improved and the erythema disappeared.

Orthognathic surgery during breast cancer treatment—A case report

Highlights • In recent years, patients with orthognathic surgery in middle-aged have come to be a more frequent occurrence.• Breast cancer is the most frequently diagnosed cancer in woman worldwide, and its prevalence rate is steadily increasing.• We experienced a case in which breast cancer was found just before the orthognathic surgery we performed a bimaxillary osteotomy, including follow-up tamoxifen administration, during breast cancer treatment.• We performed a bimaxillary osteotomy, including follow-up tamoxifen administration, during breast cancer treatment.

Examination of Diseases Requiring Oral Surgery Treated via Medical- Dental Cooperation in the Department of Oral and Maxillofacial Surgery (Biopathology), Okayama University Hospital

Objective: In recent years, the need for dental treatment and dental hygiene management within the perioperative period and supportive advanced medical treatment has been increasing. However, perioperative intervention in diseases requiring oral surgical treatment is not well understood at present. Here we report our investigation of diseases requiring oral surgical treatment in which Department of Oral and Maxillofacial Surgery (Biopathology) at Okayama University Hospital conducted medicaldental cooperation via Division of Hospital Dentistry. Methods: In the five years from April 2011 to March 2016, we have identified 310 cases that reached the Okayama University Hospital Department of Oral and Maxillofacial Surgery (Biopathology) via the Division of Hospital Dentistry. Results: The patients were treated in 22 clinical departments, the most prevalent treatment was chemotherapy, followed by surgery and then transplantation. The surgical diseases for which our department was consulted were most commonly diseases of the teeth and periodontal disease (269 cases), followed by inflammatory conditions such as implantitis and osteomyelitis, and mucosal diseases such as lichen planus and leukoplakia. The surgical procedure performed was most often tooth extraction (243 cases); there are few cases of cystectomy and sequestrum. In the majority of cases, the surgical treatment was performed on the initial examination day; in about 84% of cases, surgery was performed within 2 weeks. Conclusion: Further investigation is necessary into the practice of preventing adverse events non-dental medical departments by increasing the frequency of oral surgical intervention in appropriate cases during the perioperative period.