Takahiro Kaneko

Ridge widening and immediate implant placement: a case report.

Alveolar atrophy may present an anatomical limitation to the placement of endosseous implants. A case is described of severe maxillary alveolar atrophy with immediate implant placement associated with a ridge widening technique in accordance with a split-crest-bone manipulation. Taper-shaped implants were applied in this technique without a barrier membrane. Because this implant was small and tapped into position, it was easier to use and was considered to be appropriate for the ridge widening technique associated with immediate implant placement.

Initial management of massive oral bleeding after midfacial fracture

BACKGROUND This article reviews initial outcomes of the treatment of massive oral bleeding after midfacial fracture. METHODS Massive bleeding was defined according to the criteria of Buchanan and Holtmann. The incidence of patients who met these criteria, hematocrit, the type of fracture, time from injury to initial management, source of bleeding, duration of management, and treatment strategy were recorded. RESULTS We identified massive bleeding in the maxillofacial region in 5 of 521 patients (0.96%). All patients demonstrated profuse bleeding from the nose, and no active source of bleeding was evident in the oral cavity. Bleeding was controlled by nasal packing and temporary reduction in all patients, none of whom required artery ligation or embolization. CONCLUSION Massive oral bleeding associated with midfacial fractures is frequently derived from the nasal cavity and associated structures. Although the nose may be the cause of the bleeding, the sinuses, skull base, and nasopharynx may also have active bleeding that has cleared through the nasal cavity and nasopharynx into the oral cavity. Control of this massive nasal bleeding during the early stage can therefore improve morbidity associated with severe exsanguination.

New Bone Formation in Nongrafted Sinus Lifting With Space-Maintaining Management: A Novel Technique Using a Titanium Bone Fixation Device

PURPOSE Sinus lifting without graft materials allows new bone formation in the sinus, but the amount of bone formation varies. This study aimed to investigate whether nongrafted sinus lifting using a titanium bone fixation device can promote bone formation in the sinus. MATERIALS AND METHODS Patients with atrophic posterior maxillae jeopardizing implant stability were included. After nongrafted sinus lifting in combination with implant placement, repositioning of the bone window and additional space-maintaining management were performed by use of the bone fixation device. The primary variables recorded retrospectively included implant survival and preoperative and postoperative alveolar crest height with and without Schneiderian membrane perforation. Independent variables included patient demographics, position and dimension of the implants, complications, and follow-up period. The t test was used for comparing differences in bone levels. The implant survival rate was estimated by uses of Kaplan-Meier statistics. RESULTS The study included 11 patients (4 men and 7 women) and a total of 21 implants. Radiographically, new bone formation around the implant was generally observed in accordance with the implant apex. Postoperative alveolar crest height (mean, 10.9 ± 2.2 mm) was significantly higher compared with residual alveolar crest height (mean, 4.7 ± 1.4 mm), and no significant difference in bone formation was seen according to membrane perforation. The cumulative survival rate was 95.2%. CONCLUSIONS This nongrafted sinus-lifting procedure using a bone fixation device could attain predictable bone formation. Additional space-maintaining management using a bone fixation device in a nongrafted sinus lift offers a useful technique for promoting bone formation in the sinus.

Methotrexate‐related lymphoproliferative disorder arising in the gingiva of a patient with rheumatoid arthritis

Methotrexate (MTX) is the primary drug used in the management of rheumatoid arthritis (RA) and other immune-mediated inflammatory diseases. MTX is a strong immunosuppressive agent and has been reported to cause iatrogenic immunodeficiency-associated lymphoproliferative disorders (LPDs). Stomatitis caused by MTX-related cytotoxicity may occur, but gingival MTX-related LPDs are rare. In this article we present a case of gingival MTX-related LPD in a 60-year-old male with RA. The local findings of the gingival ulceration and alveolar bone exposure were similar to those of bisphosphonate-related osteonecrosis of the jaw. However, he had never received bisphosphonate therapy. The biopsy specimen of the gingival lesion was diagnosed as diffuse large B-cell lymphoma with Epstein-Barr virus positivity. Immediate withdrawal of MTX resulted in marked remission of the LPD.

Congenital Mucocele in the Tongue: Report of a Case

tic lesions of the oral cavity. Oral congenital diseases detected in the fetus have mostly been reported in obstetrics and pediatrics, with reports from oral and maxillofacial units a rarity. We describe a case of congenital mucocele diagnosed on prenatal ultrasonography that presented as a cystic lesion in the tongue.

Benign lymphoepithelial lesion of the parotid gland with sebaceous differentiation.

The salivary duct system in the setting of chronic sialadenitis is predisposed to undergo a variety of cellular modifications. This report documents a rare type of metaplasia of a parotid benign lymphoepithelial lesion. Epimyoepithelial islands showing focal sebaceous differentiation and pure sebaceous cell nests in addition to their usual histologic appearance were noted throughout the lesion. The possible pathogenesis is discussed through a review of the literature.

Oral lacerations during motocross: A case report

Motocross is a high-risk sport that can cause serious injuries including oral injuries. However, mouthguard use is not mandatory in motocross. This report describes a case of an oral laceration with exposure of bilateral inferior alveolar nerves as a result of a motocross accident in which the patient was not wearing a mouthguard.

Partial Protection of Paclitaxel-induced Neurotoxicity by Antioxidants.

Background/Aim: In order to search for substances that reduce the neurotoxicity of paclitaxel, the sensitivity of differentiated rat neuronal PC12 cells to paclitaxel was compared to that of malignant and non-malignant cells, and the extent to which four antioxidants can alleviate paclitaxel-induced neurotoxicity was investigated. Materials and Methods: Viability of cells was determined by the MTT method. Cytotoxicity was evaluated as the concentration that reduced cell viability by 50% (CC50). Tumor specificity of paclitaxel was determined as the ratio of CC50 against non-malignant cells to that against malignant cells. Results: Paclitaxel was three-fold more cytotoxic towards human oral squamous cell carcinoma cell lines (Ca9-22, HSC-2, HSC-3. HSC-4) than human normal epithelial and mesenchymal (human gingival fibroblast, human periodontal ligament fibroblast, human pulp cell) normal cells, confirming its antitumor potential. However, paclitaxel at as low a concentration as 5 ng/ml significantly reduced neurite formation in nerve growth factor-induced differentiated PC12 cells, although complete killing of cells was not achieved even at 2,000-fold higher concentration (10 μM). Paclitaxel-induced neurotoxicity was enhanced with the prolongation of incubation time and reduction of inoculation cell density. Four antioxidants, namely docosahexaenoic acid, acetyl-L-carnitine hydrochloride, N-acetyl-L-cysteine and sodium ascorbate, only partially protected PC12 cells from paclitaxel-induced toxicity. Conclusion: The present study suggests the involvement of both oxidative and other mechanisms in paclitaxel-induced neurotoxicity.

Change in Anticancer Drug Sensitivity During Neuronal Differentiation of PC12 Cells.

Background/Aim: Although there are many reports of anticancer drug-induced neurotoxicity, most previous data have been derived from neuronal cell models grown in a variety of culture conditions. This has prevented accurate assessment of the potency of their neurotoxicity and of changes in drug sensitivity of neuronal cells during differentiation. In this study, a simple neuronal differentiation induction system was established and the relative potency of neurotoxicity of eight anticancer drugs was compared during neuronal cell differentiation. Materials and Methods: Rat PC12 cells were induced to differentiate into neuronal cells by 50 ng/ml nerve growth factor in serum-free Dulbeccos modified Eagles medium, followed by overlay of fresh nutrients at day 3, without medium change. Cell viability was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Results: During differentiation, PC12 cells became 1.1-to more than 10,000-fold resistant to anticancer drugs. Topoisomerase inhibitors (doxorubicin, SN-38, etoposide) were the most toxic to differentiated PC12 cells, followed by docetaxel, gefitinib, melphalan, 5-fluorouracil and methotrexate. Docetaxel showed the highest cytotoxicity against undifferentiated PC12 cells, but its cytotoxicity was dramatically reduced during differentiation. Conclusion: The present study demonstrated considerable variation in the neurotoxicity of anticancer drugs during the cell differentiation process. The present simple assay system may be useful to search for neuroprotective substances.

A novel open-tray impression technique for fabrication of a provisional prosthesis on immediate load implants in a completely edentulous arch.

PURPOSE To evaluate the clinical outcome of a novel open-tray impression technique for fabrication of a provisional prosthesis supported by immediately loaded implants in a completely edentulous arch. MATERIALS AND METHODS An open-tray impression technique was evaluated in this retrospective study that included patients treated between March 2006 and October 2009. Preoperatively, a diagnostic prosthesis was delivered, and a novel open tray was fabricated based on this prosthesis. After implant placement, the impression and interocclusal record were taken simultaneously using the novel open tray. Laboratory-fabricated, screw-retained, all-acrylic resin provisional restorations were delivered on the same day of surgery. The prosthesis was assessed from the day of surgery until replacement with a definitive prosthesis. RESULTS The study included 21 patients (mean age, 64.5 years) and a total of 125 implants. Of these, 104 implants were immediately loaded. In all patients, well-fitting provisional restorations supported by a minimum of four implants were delivered. Fracture of the first molar cusp was observed in one case after 30 days. However, there was no extensive fracture in the framework or functional disorder of the prosthesis. No implant failed during the follow-up after implant surgery. CONCLUSION This protocol enabled fabrication of a well-fitting acrylic resin provisional prosthesis supported by immediately loaded implants because the impression was taken while in centric occlusion and an occlusion identical to the diagnostic prosthesis could be reconstructed.