Kazuhiro Ooi

Magnetic resonance imaging of the temporomandibular joint in patients with skeletal open bite and subjects with no dentofacial abnormalities

We aimed to record the prevalence of disc displacement and bony changes in the temporomandibular joints (TMJs) of patients with skeletal open bite. We studied 25 patients (50 joints) with skeletal open bite, 25 volunteers with no dentofacial abnormalities (50 joints), and 44 patients with closed lock and no dentofacial abnormalities (60 joints) using magnetic resonance imaging (MRI) of the TMJ. We found anterior disc displacement without reduction in 6 of the volunteers and in 24 of the patients with skeletal open bite (p=0.01). Among the 24 affected joints, 16 showed signs of bony change (67%) as did 24 of those with closed lock (40%). The fact that we found a significant difference in the incidence of anterior disc displacement without reduction and bony change between patients with skeletal open bite and control groups without deformities of the jaw indicates that these changes may be caused by skeletal open bite.

Chin Augmentation With Thin Cortical Bone Concomitant With Advancement Genioplasty

The chin plays a prominent role in establishing, not only esthetics, but also function. An incompetent lip seal and tension of the mentalis muscle in swallowing can be important symptoms. Genioplasty is one of the options for addressing the chin deformity and dysfunction caused by morphologic dcficiencies. 1 Postoperative complications can include resorption of grafted bone and a deep labiomental fold. Lateral wings of the genial segment are apt to be resorbed, occasionally leading to the so-called witchs chin appearance, 2 if combined with a deep labiomental fold. To overcome this problem, various strategies have been reported. 3 We describe a novel method to augment the chin structure with a desirable labiomental fold using thin cortical bone alone. Surgeons generally depend on radiography or computed tomography to evaluate genioplasty. However, we had the opportunity to see firsthand the actual state of bony union in these cases when subsequent anterior subapical alveolar osteotomy was performed several months later. We report 2 cases in which substantial bone augmentation was achieved.

Oral tumor resection and salivary duct relocation with an ultrasonic surgical aspirator.

We describe a procedure of oral tumor resection and salivary duct relocation with an ultrasonic surgical aspirator. After mucosal incision, resection of the underlying musculature was performed using an ultrasonic surgical aspirator. Using the apparatus, the salivary duct was easily exposed without damaging or cutting the duct. After identification of the salivary duct, salivary duct relocation was performed. After resection of the tumor, the artificial dermis was trimmed and sutured to the mucosal edges of the surgical defect. This method is a reliable and simple procedure that can be used to avoid postoperative complications such as salivary fistula or swelling of the gland.

Mandibular Coronoid Hyperplasia: A Case Report

Abstract A case of unilateral coronoid hyperplasia successfully treated by coronoidotomy with prolonged postoperative physiotherapy and reveal the postoperative radiographic changes between the sectioned part of the coronoid process and the mandibular ascending ramus is described. The patient was a 28-year-old man whose maximum mouth opening was 30 mm. A coronoidotomy of the left coronoid process was performed. Nine days after surgery, the patient started physiotherapy with a HU-OSr appliance. After coronoidotomy and physiotherapy, the maximum mouth opening had increased to 43 mm. Radiographic follow-up showed that the coronoid process apparently united with the mandibular ascending ramus, with moderate dislocation and inclination posteriorly. In the case presented, an intraoral coronoidotomy with postoperative physiotherapy for treatment of coronoid process hyperplasia allowed satisfactory and stable results in the correction of coronoid-malar interference.

Factors related to the incidence of anterior disc displacement without reduction and bony changes of the temporomandibular joint in patients with anterior open bite

PurposeWe aimed to investigate factors related to the prevalence of anterior disc displacement without reduction (ADDwoR) and bony changes of the condylar head (bony changes) in the temporomandibular joints (TMJs) of patients with anterior open bite.MethodsSubjects are comprised of 36 preoperative patients (72 joints) with skeletal anterior open bite without facial asymmetry who had undergone orthognathic surgery at the Hokkaido University Hospital; magnetic resonance imaging of the TMJ and cephalometric analysis were performed before treatment. Logistic regression analysis was performed to clarify relationships among age, overbite, overjet, ANB angle, sella to nasion (SN) to mandibular plane angle (SN–MP angle), SN to ramus plane angle (GZN angle), gonial angle, and incidence of ADDwoR or bony changes in patients with anterior open bite.ResultsFifteen patients had bilateral ADDwoR, and five patients had unilateral ADDwoR; 17 patients had bilateral bony changes, and five patients had unilateral bony changes. SN–MP angle was greater in 20 patients with ADDwoR than that in 16 patients without ADDwoR (p < 0.05). GZN angle was greater in the 20 patients showing bony changes than that in the 16 patients without bony changes (p < 0.05).ConclusionIn terms of dentofacial morphology, SN–MP angle appears to be associated with the incidence of ADDwoR, and GZN angle appears to be associated with bony changes in the TMJ.

Repair of oral mucosal defects using artificial dermis: factors related to postoperative scar contracture

OBJECTIVE To clarify wound-healing situations with artificial dermis used for the repair of oral mucosal defects, we investigated the incidence of postoperative scar contracture and studied factors related to cicatrization. STUDY DESIGN Forty patients who underwent repair of oral mucosal defects using artificial dermis participated in this study. The degree of scar contracture was recorded 1 month after surgery. To study the factors related to cicatrization, patient characteristics of sex, age, excision region, fixation used, size of the graft, and number of days for silicon seat removal were examined. Logistic regression analysis was used for analysis of the relationship between cicatrization and patient characteristics. RESULTS One month after surgery, 70% of patients had no contracture, 22.5% of patients had moderate contracture, and 7.5% of patients had severe contracture. A significant correlation was found between cicatrization and the minimum diameter of the artificial dermis (P < .001). CONCLUSIONS Reducing the minimum diameter of the artificial dermis may contribute to a decrease in scar contracture.

A Case of Calcifying Aponeurotic Fibroma Arising in the Medial Pterygoid Muscle

The tumor that was previously designated as a fibroma of the palms and soles in young children was named in 1953 by Keasbey as juvenile aponeurotic fibroma. It has subsequently become apparent that this lesion affects a much wider age range than other forms of juvenile fibromatosis and may occur in young adults and, rarely, in older adults. In view of the wide age range of patients, the term juvenile aponeurotic fibroma was changed to aponeurotic fibroma and calcifying aponeurotic fibroma. The lesion has been documented in the orthopedic literature as a slow-growing, benign, painless tumor with a predilection for the distal portions of the extremities in young children. However, there have been no maxillofacial cases in the literature. The following report describes a case of calcifying aponeurotic fibroma arising in the medial pterygoid muscle.

Factors related to the prevalence of anterior disc displacement without reduction and bony changes of the temporomandibular joint in patients with facial asymmetry

Abstract Purpose The aim of the study was to determine the factors related to the prevalence of anterior disc displacement without reduction (ADDwoR) and bony changes of the mandibular condyle (bony changes) in temporomandibular joints (TMJs) of patients with dentofacial deformity exhibiting facial asymmetry. Patients and methods A total of 75 female patients (150 joints) with facial asymmetry, who had undergone orthognathic surgery, were examined with magnetic resonance imaging (MRI) of the TMJ and cephalometric analysis. Logistic regression analysis was performed to determine whether there was a statistically significant association between age, cephalometric measurements, and prevalence of ADDwoR and bony changes. Results Facial asymmetry, the prevalence of ADDwoR, and bony changes were more frequently found on the left side than that of the right side. Unilateral ADDwoR ( n =28) and unilateral bony changes ( n =14) were only found on the deviated side. The difference between the distance of upper incisal midpoints and lower incisal midpoints from the facial midline (U1–L1 distance) was significantly larger in 36 patients with ADDwoR and 52 patients with bony changes. According to logistic regression analysis, U1–L1 distance might be related to the prevalence of ADDwoR and bony changes in the TMJs with facial asymmetry. Conclusion U1–L1 distance related to the prevalence of ADDwoR and bony changes in TMJs of patients with dentofacial deformity exhibiting facial asymmetry.

Intra-Articular Fracture of the Mandibular Condyle: A Case Report

Abstract The authors describe a case of intra-articular fracture of the left mandibular condyle, successfully treated by the pumping technique in the upper and lower joint cavities, and show arthroscopic findings in these cavities. The patient was a 15-year-old boy whose maximum mouth opening was 30 mm. Computed tomography revealed a left intra-articular sagittal fracture of the condylar head. Aspiration of the hematoma in the upper and lower joint spaces was performed with ten pumping actions. In the upper and lower joint spaces, arthroscopic examination revealed the disappearance of the hematoma. The patient continued opening, protrusive, and lateral excursive exercises. One month after the surgery, the maximal interincisal distance was improved to 45 mm with straight opening. In the case presented, mouth-opening exercises, along with the pumping technique for treatment of an intraarticular fracture of the mandibular condyle, allowed satisfactory and stable results in the improvement of limited mouth movement.

Relationship between the Effectiveness of Arthrocentesis under Sufficient Pressure and Conditions of the Temporomandibular Joint.

Background. The purpose of this study is to investigate the conditions of the temporomandibular joint relative to the effectiveness of an arthrocentesis-like enforced manipulation technique followed by irrigation under high pressure in patients with closed lock. Methods. We performed arthroscopic examination and manipulation followed by irrigation as the initial treatment in 50 joints with closed lock. Relationship between the effectiveness of the procedure and conditions of the temporomandibular joint was statistically analyzed using multiple regression analysis. Results. Significant inverse correlations were found between the extent of improvement in maximum mouth opening after treatment and the initial maximum opening before treatment. There were no significant correlations between improvement of joint pain at mouth opening and in biting and conditions of the temporomandibular joint. Conclusions. Pathologic conditions of the temporomandibular joint did not have an influence on the efficacy of the technique. This result suggests that this procedure has wider application than conventional arthrocentesis.