Kaori Igawa

Comparison of Material-Related Complications After Bilateral Sagittal Split Mandibular Setback Surgery: Biodegradable Versus Titanium Miniplates

PURPOSE The aim of the present prospective study was to compare material-related complications using biodegradable and titanium miniplates after bilateral sagittal split mandibular setback surgery. PATIENTS AND METHODS The subjects included 200 Japanese adults (67 men and 133 women, age range 18 to 45 years) with jaw deformities diagnosed as mandibular prognathism. All patients were prospectively and consecutively randomized to 2 study groups, receiving biodegradable or titanium fixation plates. Of the 200 patients, 110 underwent bilateral sagittal split ramus osteotomy with a biodegradable fixation plate and 90 underwent bilateral sagittal split ramus osteotomy with a titanium metal plate. The clinical records and radiologic findings of the patients were reviewed, and the incidence of material-related complications was compared. RESULTS The incidence of postoperative complications and breakage in the biodegradable group was 8.2% (9 cases) and in the titanium group was 3.3% (3 cases). No statistically significant difference in the incidence of complications was found between the 2 groups. Fractures of the biodegradable plate occurred at a significantly greater frequency in patients with asymmetry than in patients without asymmetry. CONCLUSION Biodegradable plates were reliable with minimal material-related complications. However, the use of biodegradable plates should be recommended for minimally loaded situations.

Extensive Necrosis of Pleomorphic Adenoma in the Soft Palate: A Case Report and Review of the Literature

p v r r t v g e m i m O b T o a c o w leomorphic adenoma is the most common neoplasm f major and minor salivary glands. Although pleoorphic adenoma is uncommonly associated with ystic change or partial hemorrhagic necrosis, sponaneous infarction appears to be very rare. Here, we resent a case of pleomorphic adenoma with extenive necrosis in a 34-year-old man, arising from the inor salivary glands of the soft palate. Furthermore, he histogenesis of necrotic pleomorphic adenoma is iscussed.

Risk factors for breakage of biodegradable plate systems after bilateral sagittal split mandibular setback surgery.

The aim of this retrospective study was to evaluate the risk factors associated with breakage of biodegradable plate systems after bilateral sagittal split mandibular setback. We studied 169 Japanese adults (62 men, 107 women; age range 16-53 years) with deformities of the jaw diagnosed as mandibular prognathism. All patients were treated by bilateral sagittal split osteotomy (BSSO) with 2 biodegradable fixation plates and screws at the anterior mandibular ramus. We collected the following data from the medical records and radiological findings: sex; age; degree of setback; presence of asymmetry; presence of open bite; operation; design of the plate; operating time; and blood loss. Multiple logistic regression analysis was used to find the factors that were independently associated with the dependent variable: breakage of the biodegradable plate system. In 10 of the 169 patients (6%) the biodegradable plate system for the BSSO broke. Factors that influenced whether or not the biodegradable plate system fractured were if they were asymmetrical (odds ratio (OR) 5.35; P=0.02) and had an open bite (OR 5.20; P=0.02). Asymmetry or open bite was significantly associated with breaks in the biodegradable plate system. Biodegradable plates should be used only when loading is minimal.

Measurement of Muscle Hardness Using a Hardness Meter: Application to the Masseter and Temporal Muscles and Reproducibility of Measurement

ABSTRACT This study was designed to evaluate the intra-examiner and inter-examiner reliability of measurements of masticatory muscle hardness and to confirm that the muscle hardness increases with contraction using a commercially available muscle meter. Twenty healthy asymptomatic female subjects participated in this study. Hardness was expressed as numerical relative values (0–100). First, muscle hardness was measured at a standardized point located in the masseter muscle and temporal muscle in a randomized order by two examiners, and again by one of the same examiners after ten minutes for the reproducibility study. Then the muscle hardness was measured at each point for 0 kgf, 3 kgf, 6 kgf, and 9 kgf levels of bite force. As a result, intradass correlation coefficient (ICC) analysis revealed good intra-examiner reliability in the masseter muscle (ICC = 0.711), good intra-examiner reliability in the temporal muscle (ICC = 0.643), good inter-examiner reliability in the masseter muscle (ICC=0.631), and unacceptable inter-examiner reliability in the temporal muscle (ICC = 0.008). Also, our results showed that muscle hardness increased with contraction, and relationships with a slope of 1.229, a y-intercept of 62.513, and a correlation coefficient of 0.448 were observed in the masseter muscle. However, no correlation was found between muscle hardness and bite force in the temporal muscle. The findings indicate that measurement of hardness provides reliable physiological information about the masseter muscle in this setting.

The role of spinal serotonin receptor and alpha adrenoceptor on the antiallodynic effects induced by intrathecal milnacipran in chronic constriction injury rats.

Milnacipran, a reuptake inhibitor of noradrenaline (NA) and serotonin (5-HT), elicits an antiallodynic effect in rats with neuropathic pain; however, the role of NA and 5-HT receptors in the induction of the antiallodynic effect of milnacipran remains unclear. Thus, we examined the effects of prazosin as an α1 adrenoceptor antagonist, yohimbine as an α2 adrenoceptor antagonist, metergoline as a 5-HT1, 5-HT2 and 5-HT7 receptor antagonist, cyanopindolol as a 5-HT1A/1B receptor antagonist, ketanserin as a 5-HT2 receptor antagonist, and ondansetoron as a 5-HT3 receptor antagonist on the antiallodynic effect of milnacipran in neuropathic rats with chronic constriction injury (CCI). The CCI rats expressed mechanical and thermal allodynia, which was attenuated by intrathecal injection of milnacipran. Yohimbine, but not prazosin, reversed the milnacipran-induced antiallodynic effect. The antiallodynic effect of milnacipran was also reversed by metergoline, ketanserin and ondansetron, while cyanopindolol reversed the antiallodynic effect on mechanical, but not thermal stimulation. Furthermore, c-Fos expression in lamina I/II of the spinal dorsal horn was enhanced by thermal stimulation and the enhanced expression of c-Fos was suppressed by milnacipran. This effect of milnacipran was reversed by yohimbine, metergoline, katanserin and ondansetron, but not prazosin. These results indicate that the effect of milnacipran on mechanical and thermal allodynia and c-Fos expression is elicited through the α2 adrenoceptor, but not α1 adrenoceptor, and 5-HT2 and 5-HT3 receptors; furthermore, the 5-HT1A/1B receptor is involved in mechanical allodynia, but not thermal allodynia.

Preoperative Ultrasound Assessment of Tumour Thickness in Tongue Carcinomas

Objective: To evaluate the clinical usefulness of intraoral ultrasonography compared with computed tomography and magnetic resonance imaging to assess tumour thickness in patients with carcinoma of the tongue. Patients and Methods: Twenty eight patients with squamous cell carcinoma of the tongue who were treated by tumour resection with or without neck dissection and/or preoperative adjunctive therapy, were reviewed. Tumour thickness was assessed preoperatively by ultrasonography, computed tomography, or magnetic resonance imaging and the findings were compared with postoperative measurements and histological grading obtained from histological sections of tongue resection specimens. Results: The ultrasound findings were of moderately well-defined sonolucent lesions. The intraoral ultrasound depth correlated with tumour stage, tumour size, nodal status, mode of invasion (Y-K classification), muscular invasion, and invasive front grading. Ultrasound depth did not correlate with growth type, differentiation, or Anneroths malignancy. The mean intraoral ultrasound depth was 10.5 mm (SD, 8.1 mm) and the mean tumour depth assessed by histological sections was 7.1 mm (SD, 6.3 mm). There was a significant correlation between the ultrasound depth and the tumour depth by histological section (r = 0.976; p < 0.0001). Measurements by computed tomography and magnetic resonance imaging also correlated with tumour depth by histological section (r = 0.823; p = 0.0018, and r = 0.778; p < 0.0001, respectively). Conclusion: These findings suggest that ultrasonography is a reliable method for the preoperative assessment of tumour thickness in tongue carcinoma.

Epidermal choristoma arising on the midline gingiva as a congenital epulis: A case report

We report an extremely rare case of epidermal choristoma in the midline of the maxillary gingiva. A 2-month-old Japanese boy presented with a polypoid mass in the midline of the maxillary gingiva. The initial clinical diagnosis was congenital epulis. Microscopic examination revealed a granular cell layer and melanin pigmentation within the basal cell layer. Furthermore, sebaceous glands and hair follicles were observed within the connective tissue. The histological diagnosis was therefore epidermal choristoma, based on clinical microscopic observations.

Oral tonsil in the floor of mouth : Ectopic oral tonsillar tissue simulating benign neoplasms

Abstract Oral tonsils, ectopic sublingual tonsillar tissue, manifest as an asymptomatic, nonulcerated, freely movable nodule. We present a case of a 28-year-old female with ectopic tonsillar tissue in the anterior floor of the mouth. The lesion was totally removed under local anesthesia. The microscopic examination showed well demarcated and encapsulated lymphoid tissue with lymphoid follicles and central lacuna-like squamous epithelium covering space. These findings are similar to tonsillar tissue, and the case was finally diagnosed as sublingual oral tonsil. This article underlines that oral tonsils occur more frequently than is generally recognized, and the importance of differential diagnosis of soft tissue nodules in the oral floor.

Predictive Markers for Late Cervical Lymph Node Metastasis in Patients with N0 Squamous Cell Carcinoma of the Tongue

Abstract Objective: To find useful markers for predicting late cervical metastasis in patients with N0 squamous cell carcinoma of the tongue. Materials and Methods: The clinicopathological features of 57 consecutive patients with previously untreated N0 squamous cell carcinoma of the tongue were reviewed. Thirty patients had T1 disease, 20 had T2 disease, and 7 had T3 disease. All patients were treated with partial glossectomy without elective neck dissection. Clinicopathological factors were analysed to determine the factors predicting late cervical lymph node metastasis. Results: The overall cervical lymph node metastasis rate was 19.3%. The clinicopathologic factors significantly associated with the development of cervical lymph node metastasis were tumour size (30 mm), tumour depth (4 mm), differentiation (moderate), mode of invasion (G4C 4D), microvascular invasion (present), muscle invasion (present), and invasive front grading (12 points). In a multivariate logistic regression analysis, invasive front grading ≥12 points in squamous cell carcinoma of the tongue with a tumour depth ≥4 mm had predictive value for late cervical lymph node metastasis. Conclusion: The results indicate that patients with N0 invasive tongue carcinoma with a tumour depth ≥4 mm or invasive front grading ≥12 points should be considered at high risk for late cervical lymph node metastasis. These factors should be considered in the decision to electively treat the neck.

Distribution of hemokinin-1 in the rat trigeminal ganglion and trigeminal sensory nuclear complex

OBJECTIVE A new mammalian tachykinin peptide encoded in a TAC4 gene was identified and designated as hemokinin-1 (HK-1). A representative of the tachykinin peptide family is substance P (SP), and the function of SP has been well characterized as a pain transmitter or modulator, while it is possible that HK-1 is involved in pruriceptive processing, but, as yet, the distribution of HK-1 peptide in the trigeminal sensory system is still unknown. Thus, the aim of the present study was to elucidate the distribution of HK-1, while comparing the expression of SP, in the trigeminal ganglion and trigeminal sensory nuclear complex. DESIGN The trigeminal ganglion and the brain stem of male SD rats were used in the immunohistochemical study. Since the amino acid sequence in the carboxyl-terminal regions of HK-1 and SP is common, polyclonal antibodies of HK-1 and SP derived from 6 amino acids consisting of amino-terminal regions of these peptides were produced in guinea pig and rabbit, respectively. The immunohistochemical staining of HK-1 and SP was conducted using frozen sections of the trigeminal ganglion and brain stem in rats. RESULTS Immunohistochemical studies revealed the expression of HK-1 in small- and medium-sized trigeminal ganglion neurons, in the paratrigeminal nucleus, and in lamina I of the trigeminal nucleus caudalis, while there was no immunoreactivity of HK-1 in the trigeminal nucleus principalis, trigeminal nucleus oralis, and trigeminal nucleus interpolaris. CONCLUSION These findings indicate that HK-1 is a target molecule for treatment of itch in the orofaicial regions.