Joji Sekine

Preoperative assessment of the relationship between the mandibular third molar and the mandibular canal by axial computed tomography with coronal and sagittal reconstruction

OBJECTIVE We sought to evaluate the relationship between the mandibular third molar and the mandibular canal by using axial computed tomography with coronal and sagittal reconstruction for third molar surgery. STUDY DESIGN Forty-seven impacted third molars in 41 patients were found in close association with the mandibular canal during a panoramic radiographic assessment. The relationship between the mandibular third molar and the mandibular canal was evaluated by using computed tomography and compared in terms of operative exposure of the inferior alveolar nerve and postoperative labial dysesthesia. RESULTS Twenty-four (51%) mandibular canals were buccal relative to the third molar, 12 were lingual, 9 were inferior, and 2 were between roots. At the time of the surgical procedure, the inferior alveolar nerve was visible in 7 patients. Postoperative lower lip dysesthesia occurred in 1 patient whose mandibular canal was in the lingual position. CONCLUSIONS Axial computed tomography with coronal and sagittal reconstruction provides useful information to surgeons regarding the relationship between the mandibular third molar and the mandibular canal.

Bilateral pneumothorax with extensive subcutaneous emphysema manifested during third molar surgery. A case report.

This report describes a case of bilateral pneumothorax with extensive subcutaneous emphysema in a 45-year-old man that occurred during surgery to extract the left lower third molar, performed with the use of an air turbine dental handpiece. Computed tomographic scanning showed severe subcutaneous emphysema extending bilaterally from the cervicofacial region and the deep anatomic spaces (including the pterygomandibular, parapharyngeal, retropharyngeal, and deep temporal spaces) to the anterior wall of the chest. Furthermore, bilateral pneumothorax and pneumomediastinum were present. In our patient, air dissection was probably caused by pressurized air being forced through the operating site into the surrounding connective tissue.

Enhancement of the photodynamic antitumor effect by streptococcal preparation OK-432 in the mouse carcinoma.

Abstract Biological response modifier antitumor effects are enhanced by the activation of the host defense mechanisms. We have investigated the antitumor effect of photodynamic therapy (PDT) and/or local administration of a biological response modifier, the streptococcal preparation OK-432, on transplanted NR-S1 mouse squamous cell carcinoma. Hematoporphyrin oligomers (20 mg/kg body weight) were used to photosensitize PDT. A pulsed Nd:YAG dye laser, tuned at 630 nm, was used as the light source. The laser power was 15 mJ cm−2 pulse−1, and the irradiation time was 40 min. The photosensitizer was injected intraperitoneally 48 h before laser irradiation. Where used, OK-432 was injected into the tumor either 3 h prior to PDT or immediately afterwards. The antitumor effects were evaluated 48 h after each protocol by (a) estimating the area of tumor necrosis (%) in hematoxylin/eosin-stained specimens, and (b) bromodeoxyuridine immunohistochemistry. Furthermore, the tumor sizes were evaluated 3, 7 and 10 days after each protocol, and the survival time after each protocol was evaluated as well. The anti-tumor effect of PDT was enhanced by administration of OK-432 3 h before PDT, whereas the administration of OK-432 immediately after PDT did not potentiate a PDT antitumor effect. Treatment with OK-432 alone had little effect on tumors. Photodynamic therapy in combination with local administration of OK-432 3 h before PDT is considered to be a useful treatment modality.

Oral symptoms including dental erosion in gastroesophageal reflux disease are associated with decreased salivary flow volume and swallowing function

BackgroundThis preliminary clinical study aimed to evaluate the effects of salivary flow volume and swallowing function on oral symptoms including dental erosion in gastroesophageal reflux disease (GERD).MethodsThe subjects were 40 GERD patients and 30 (15 younger, 15 older) healthy controls. Detailed medical, dietary, and dental histories were obtained to identify individual behavioral habits potentially associated with dental erosion. Oral examination evaluated dental erosion and determined scores for the decayed, missing, filled (DMF) index, the papillary, marginal, attached (PMA) index for gingivitis, and the Simplified Oral Hygiene Index (OHI-S). Salivary flow volume and swallowing function were evaluated by the Saxon test and repetitive saliva swallowing test, respectively.ResultsThe DMF index and OHI-S scores differed significantly between all 3 groups. The PMA index was significantly different between the GERD group and the two control groups. The prevalence of dental erosion was 24.3% in the GERD group (0% in the control groups). No specific relationship was found between the incidence of dental erosion and dietary history or behavioral habits. The Saxon test results were significantly lower in the GERD group than in both the control groups. Frequency of swallowing was significantly lower and time to first swallow was significantly longer in the GERD group than in the two control groups.ConclusionsOral symptoms in GERD are likely to be associated with impaired salivary flow volume or swallowing function. Treatment for the oral dryness induced by reduced salivary flow volume and rehabilitation for swallowing function could be indicated in patients with GERD.

Applicability of buccal fat pad grafting for oral reconstruction

This study evaluated the applicability of pedicled buccal fat pad grafting for the reconstruction of defects surgically created during oral surgery. A buccal fat pad graft was applied in 23 patients (5 males, 18 females; mean age 68.3 years) between 2003 and 2011. The graft was used to cover surgical defects of the palate, maxilla, upper gingiva, buccal mucosa, lower gingiva, oral floor, and temporomandibular joint region. Size of the surgical defects ranged from 15mm×12mm to 30mm×40mm; size of the buccal fat pad ranged from 15mm×12mm to 43mm×38mm. A pedicled buccal fat pad was prepared by incising the maxillary vestibule following primary surgery, and the surrounding connective tissue was preserved to supply nutrition to the pedicle during surgery. The buccal fat pad was placed on the raw surface of soft tissue or bone surface and sutured to the surrounding tissue of the defect. Complete epithelialization was observed within 4 weeks postoperatively. There were no complications or functional disorders during follow-up. Buccal fat pad grafting appears to be feasible for the reconstruction of surgically induced defects, and can be extended to the palate, mandible, mouth angle, and temporomandibular joint region.

Application of magnetic resonance imaging and ultrasonography to preoperative evaluation of masseteric hypertrophy.

A case of unilateral masseteric hypertrophy in a 30-year-old man is described. Preoperative evaluation was performed by magnetic resonance imaging (MRI), computed tomography (CT) and ultrasonography (USG). MRI could delineate not only the border between medial and lateral layers of the masseter but also delineate the hypertrophic portion. MRI also provided more information in respect of the masseter muscle as well as the other masticatory muscles and the surrounding tissues than CT. USG was useful because of its real-time processing, especially in this case where facial asymmetry was emphasized during mastication. We resected the medial lower-half of the masseter intraorally based on these imagings and obtained a successful result.

Bromodeoxyuridine Immunohistochemistry for Evaluating Age-Related Changes in the Rat Mandibular Condyle Decalcified by Intravenous Infusion

Age-related changes in cell proliferation kinetics of the mandibular condyle were studied in Sprague-Dawley rats using bromodeoxyuridine (BrdUrd) immunohistochemistry in decalcified, paraffin-embedded tissues. Intraperitoneal injection of 40 mg/kg BrdUrd was given 1 hr before animal sacrifice. Continuous perfusion of EDTA solution via the left ventricle shortened the decalcification time. Immunohistochemical staining was performed with monoclonal anti-BrdUrd antibody. BrdUrd labeled cells, i.e., the S-phase cells, were clearly visible with well-preserved cytological detail. Their nuclei exhibited homogeneously stained granules. The labeling index in the intermediate zone of the condyle decreased with increasing age of the animals. This method is useful for evaluating physiological and pathological changes of the rat mandibular condyle as well as other bones and joints.

A comparative study of epithelialization of subcutaneous fascial flaps and muscle-only flaps in the oral cavity: A rabbit model

Epithelialization of subcutaneous fascial flaps and muscle-only flaps used for reconstruction of the oral mucosa were studied in a rabbit model. Angiography was performed to help to design a subcutaneous cervical fascial flap and a cleidomastoid muscle-only flap. These flaps were transferred into a mucoperiosteal defect on the mandibular alveolus. The flaps were gradually infiltrated by acute inflammatory cells from the periphery and then replaced by granulation tissue originating from the oral mucosa. The epithelialization was by secondary intention. An epithelial tongue from the surrounding epithelium migrated onto the granulating flaps with eventual coverage after three weeks. After two months, the muscle-only flap was covered by a poorly organized epithelium, different from the highly uniform epithelium in the fascial flap. The granulation tissue which replaced the muscle-only flap matured to fibrous tissue, associated with severe contraction. This was characterized by dense regular collagen fibers, no elastic fibers, and few capillaries, while the fibrous tissue which replaced the fascial flap was characterized by random collagen and elastic fiber morphology and numerous dilated blood vessels, and was associated with mild contraction. This experiment supports the view that the different extracellular matrices of these flaps may play a role in epithelial configuration and contraction.

Cell kinetics in mandibular ameloblastic fibro-odontoma evaluated by bromodeoxyuridine and proliferating cell nuclear antigen immunohistochemistry : case report

A case of ameloblastic fibro-odontoma in a 10-year-old Japanese male patient is presented. Bromodeoxyuridine (BrdU) and proliferating cell nuclear antigen (PCNA) immunohistochemistry were applied to investigate the cell kinetics of this lesion. The tumour proliferation activity was individually evaluated through the labelling index (LI) at the epithelial and mesenchymal components. The LI of BrdU was 0.9% in the epithelial and 2.1% in the mesenchymal component, while the LI of PCNA was 2.2% in the epithelial and 7.7% in the mesenchymal component. These immunohistochemical investigations suggest that the mesenchymal component was more proliferative than the epithelial component. Such an immunohistochemical investigation may be useful in evaluating the proliferative potential of odontogenic tumours.

The retromandibular transparotid approach for reduction and rigid internal fixation using two locking miniplates in mandibular condylar neck fractures

We evaluated the safety, efficacy, and morbidity associated with the treatment of displaced mandibular condylar neck fractures using a retromandibular transparotid approach to reduce and rigidly fix using two 2.0-mm locking miniplates. Our surgical inclusion criteria were: patient selection of open reduction and fixation, displaced unilateral condylar fractures with derangement of occlusion, and bilateral condylar fractures with an anterior open bite. The study group consisted of 19 patients who underwent surgery for 19 mandibular condylar neck fractures; patients were analyzed prospectively, with more than 6 months of follow-up, and were evaluated in terms of functional results, scar formation, postoperative complications, and stability of fixation. The results showed that functional occlusion identical to the preoperative condition and correct anatomical reduction of the condylar segments in centric occlusion, followed by immediate functional recovery, was achieved in all patients. No patient suffered from any major or permanent complication postoperatively, although there were two cases (11%) of temporary facial nerve palsy, which resolved completely within 3 months. Surgical scars were barely visible. The retromandibular transparotid approach with open reduction and rigid internal fixation for displaced condylar neck fractures of the mandible is a feasible and safe, minimally invasive surgical technique that provides reliable clinical results.