Postoperative evaluation of jaw function with restricted mandibular movement resulting from hyperplasia of masticatory muscle aponeurosis

Poster I / B o n e Materials/Bone Regeneration of temporomandibular disorder (TMD). 58 temporomandibular joints from 29 TMD patients (14 men & 15 women) were evaluated. The relative signal intensity of retrodiscal tissue in T2-weighted MRI was referenced to brain gray matter size of the same region of interest (ROI). The collected data was compared to disc positions (normal, anterior disc displacement with reduction, anterior disc displacement without reduction). In addition, the presence of condylar degenerative changes and joint effusion were observed using the MRI. 1. The relative signal intensity of retrodiscal tissue was significantly increased when degenerative changes were seen. 2. The relative signal intensity of retrodiscal tissue was significantly increased when joint effusion was present. 3. High signal intensity was also observed when the disc was displaced without reduction. Evaluating the relative signal intensity of retrodiscal tissue of TMJ using a T2-weighted MRI is valuable as a non-invasive tool for diagnosing the procession of TMD. i-~-I

POSTOPERATIVE EVALUATION OF JAW FUNCTION WITH RESTRICTED M A N D I B U L A R M O V E M E N T RESULTING FROM H Y P E R P L A S l A OF MASTICATORY MUSCLE A P O N E U R O S l S

S. Iwamoto 1 , H. Kubo 1 , M. Goto 1 , K. Yamada 2, Y. Yotsui 3, T. Arika 4, S. Morita 2 , K. Kakudo 1 . 1Second Department of Oral and Maxillofacial

Surgery, Osaka Dental University, Japan; 2First Department of Oral and Maxillofacial Surgery, Osaka Dental University, Japan; 3Department of Oral Radiology, Osaka Dental University, Japan; 4Department of Oral and Maxillofacial, Japan The purpose of this study was to evaluate jaw function after masseter aponeurectomy and coronoidectomy in a case of restricted mandibular movement resulting from hyperplasia of the muscle aponeurosis. Of all patients with disturbances of mouth opening who visited the department of Oral and Maxillofacial Surgery, Osaka Dental University Hospital between November 1, 1997 and December 31, 2004, three patients had no findings from magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ), orthopantomogram, and CT (computed tomography) arthrography of TMJ. However, thickened aponeurosis was evident at both sides of masseter and temporal muscles with MRI. From these observations, three patients were diagnosed with hyperplasia of masticatory muscle aponeurosis and underwent masseter aponeurectomy and coronoidectomy intra-orally under general anesthesia. Physical therapy with a mouth gag was started the day after the surgery. The mean mouth opening range improved to 20 mm to 35 mm or more by the seventh training day. In this study, electromyography (EMG) of the masseter muscle and temporal muscle was obtained on both sides to evaluate jaw function after masseter aponeurectomy and coronoidectomy. Muscle activity was assessed as the average difference between maximum and minimal values at EMG from the first to the fifth biting cycle, on the seventh day after surgery. The mean preoperative muscle activity of the masseter muscle decreased from 2171mV to 299mV and from 2661mV to 343mV in the right and left side masseter muscle, respectively. In the temporal muscle, the mean preoperative muscle activity decreased from 2266mV to 939mV, and from 2350mV to 1307mV in the right and left side temporal muscle, respectively (p<0.05). Although muscle activity was followed for one month without improvement, the recovery tendency was shown after the second month. From these cases, we confirmed that sagittal MRI of the masseter and temporal muscles is a useful diagnostic modality in assessing muscle aponeurosis before operation and that masseter aponeurectomy and coronoidectomy are effective methods for cases of restricted mandibular movement resulting from hyperplasia of the muscle aponeurosis. This study suggested that at one month after surgery is the borderline, when muscle activity will be increased, myositis is improving and everyday life activities, such as eating can be performed. [-P--~ TMJ OSTEINTEGRATED PROSTHESIS SYSTEM W. Genovesi. Hospital 9 de Julho, S#o Paulo, Brasil The purpose of this study is show a new TMJ prosthesis system. Embassed in orthopaedics principals and in osteintegration implant, a new TMJ posthesis system was developed. After studying and observing 30 dries mandibles after condylectomy, was observed that the area in the ramus was about 4.5 mm in diameter and in lengh the ramus was about 35 mm, with these measures we decided introduce a pilar intra medular and a second pilar was developed to be used intra the first pilar, a condyle head was installed over the second pilar an locked with screw. It was manufacturated in laminated gold with silver. The glenoid fossa

121 was covered with Poliethylene UVA, high pressure.The first surgery was performed in 2001. Using an Endaural incision with a little extension to temporal region, dissection was done, the ankylosis mass was found, a low condylectomy was performed, and with a dental implant kit, the bone was drilled with the same step for dental implant, after the bone be drilled, the intra medular pilar was installed. The glenoid fossa was covered with glenoide fossa prosthesis and fixed with 3 micros crews. After this, a second pilar and condyle head, locked with screw was installed. Suture was performed plan by plan. After the surgery all patients were underwent to the physical therapy assisted by a physical therapist to return their joints to normal range of motion (35 to 40 mm). After 3 years 8 months from the first surgery, all three patients have free range of motion of their joints, vertical mandibular movements 35 to 38 mm, lateral excursion in contra-lateral side 5 mm, protrusive excursion 4.5 mm. In the Xray evolution was not observed bone radiolucency around the pilar intra medular, neither ectopic bone formation around the condyle head. This new TMJ prosthesis system comes to substitute the conventional system, because this system allows the surgeon change the pilar intra medular in the future, like in orthopaedic surgery for the hips. Different then others systems that do not allow us surgeons change it. I - P - ~ THE ROLE OF A R T H R O C E N T E S I S A N D I N T R A A R T I C U L A R T E N O X l C A M INJECTION IN T E M P O R O M A N D I B U L A R DISORDERS I. Aktas, "~ Emes, M. Ordulu, S. Yalcin. Department of Oral and Maxillofacial Surgery, Istanbul University, Faculty of Dentistry, Istanbul, Turkey To examine the clinical effects of arthrocentesis and intraarticular tenoxicam injection in temporomandibular disorders. 20 patients having temporomandibular disorders were treated in Istanbul University, Faculty of Dentistry, Department of Oral and Maxillofaical Surgery. 10 patients were treated by arthrocentesis while the other 10 were treated by intraarticular tenoxicam injection following arthrocentesis. Temporomandibular joint (TMJ) pain, mouth opening, joint sound and mandibular movement were recorded in both of the groups. Patients treated with both arthrocentesis and tenoxicam injection had relief in TMJ pain, but the duration of pain relief was quite longer in the tenoxicam group. There were no difference in mouth opening, joint sound and mandibular movement between the two groups. Arthrocentesis and application of intraarticular tenoxicam injection are conservative methods in the treatment of temporomandibular disorders so it is better to try them before further surgery.

Bone Materials/Bone Regeneration ~--~-1 REGENERATIVE MEDICINE FOR J A W B O N E USING POLY(LLACTIC ACID) MESH A N D PARTICULATE C A N C E L L O U S BONE A N D M A R R O W ]i Yamazaki, ]i Koike, S. Uehara, Y. Kinoshita, K.Y. Ikada. Department

of Dentistry and Oral Surgery, Komoro Kosei General hospital Institute for Frontier Oral Science, Kanagwa Dental Coflege Suzuka University of medical Science, Japan This study expounds on our long-term clinical observations of reconstruction of mandibular critical defects and blow-out fractures of the orbital floor involving globe displacement and restricted eye motility cases using poly(L-lactic acid) mesh and transplantation of particulate cancellous bone and marrow (PCBM). Methods: Twelve cases (seven men, five women; ages ranging from 13 to 84 years; six malignant tumors, four benign tumors, and two fractures) underwent mandibular reconstruction using PLLA mesh trays and PCBM. Nine cases (seven men, two women; 13 to 64 years of age) using PLLA mesh sheets and PCBM for blowout fractures of the orbital floor were treated at Komoro Kosei General Hospital. PCBM was taken from the iliac bone and grafted onto PLLA mesh trays/sheets that were shaped to the mandibular defects or orbital floor defects and fixed with stainless steel wires. The follow up period was one to nine years (average of 5.4 years). Treatment results were evaluated by X-ray and clinical findings. Additional differences in eye motility between pre- and post-surgery were examined for the orbital floor fractures, and ophthalmologic assessments were made. Results: Twelve