Masahiko Toyama

Natural Course of Untreated Symptomatic Temporomandibular Joint Disc Displacement without Reduction

In some patients with disc displacement without reduction, the symptoms of pain and decreased range of motion have been observed to resolve spontaneously over time without treatment. The natural history of this condition, however, is not well-understood. Thus, to study the natural course of disc displacement without reduction, we followed 40 patients without treatment for a period of 2.5 years. The diagnosis was established by history and physical examination and confirmed with magnetic resonance (MR) imaging. After 2.5 years, 43% of the patients were asymptomatic, 33% had decreased symptoms, and 25% of the patients showed no improvement or had required treatment. MR evidence of osteoarthritis and advanced stages of internal derangement at the initial evaluation was associated with a poor prognosis. The result of this prospective cohort study indicated that approximately 40% of patients with symptomatic disc displacement without reduction will be free of symptoms within 2.5 years, one-third will improve, whereas one-quarter will continue to be symptomatic. This knowledge should be valuable for the treatment planning and evaluation of prognosis of patients with non-reducing symptomatic disc displacement.

Correlation between preoperative mouth opening and surgical outcome after arthroscopic lysis and lavage in patients with disc displacement without reduction

PURPOSE This study was designed to evaluate the efficacy of arthroscopic lysis and lavage for patients with limited mouth opening. The relationship between preoperative mouth opening and the surgical outcome was determined. METHOD Fourteen patients with 16 internally deranged joints were treated by arthroscopic lysis and lavage. All had received 10.4 (7 to 19) months of nonsurgical treatment before arthroscopy. The preoperative magnetic resonance images showed anterior disc displacement without reduction in all treated joints. RESULTS Twelve of the 14 patients (86%) showed good reduction in pain and improved range of jaw movement on average follow-up of 28.5 (13 to 66) months. Two patients showed no improvement after arthroscopy and required open surgical procedures. The preoperative mouth opening of the successful group averaged 29.4 (22 to 35) mm, whereas the two failed cases had 10- and 19-mm openings, respectively (P < .05). CONCLUSION Persistent limitation of mouth opening of more than 22 mm after nonsurgical treatment has a good prognosis when treated by arthroscopic lysis and lavage. However, those with greater limitation should probably have earlier surgical intervention.

Observer agreement in the detection of proximal caries with direct digital intraoral radiography.

OBJECTIVE The aim of this study was to compare several values for consistency obtained by charged-coupled-device-based direct digital intraoral radiography with those obtained by conventional film-based radiography to evaluate observer agreement in determining the depth of proximal caries. STUDY DESIGN A total of 93 proximal surfaces on radiologic images that were obtained by both the conventional film-based bite-wing technique and by direct digital intraoral radiography were evaluated by six observers. One of these observers also evaluated the same images six months after the initial evaluation. The kappa value, consistency ratio, agreement ratio, and Kendalls correlation coefficient were calculated for interobserver and intraobserver agreement. RESULTS The overall kappa values for interobserver agreement were 0.439 and 0.424 in the direct digital system and the film-based radiography, respectively. The depth-related change of the values showed similar patterns in the two modalities for both interobserver and intraobserver agreement. CONCLUSION The digital intraoral system resulted in no deterioration in observer agreement, and it presents no problems for clinical use with respect to the reliability of diagnosis.

Colour Doppler sonographic analysis of blood-flow velocity in the human facial artery and changes in masseter muscle thickness during low-level static contraction

Muscle oedema, which can be seen as a thickness increment by ultrasonography, is important in provoking pain and fatigue during low-level contraction. Although oedema is related to the balance of inflow and outflow of blood, there are no data on the correlation between muscle thickness change and blood-flow. Blood-flow velocities in the facial artery and the muscle thickness changes were measured by colour Doppler ultrasonography in 30 healthy volunteers during 20 min contraction with 10% of maximum force. Thickness and velocity changes both reached a peak in the initial phase of contraction. The initial change of thickness did not correlate with the velocity in the facial artery, while those immediately after exercise showed a high correlation. The velocity changes in the facial artery might depend on both the general response to contraction and local metabolic or mechanical factors in the contracted masseters.

Single-channel thin-fiber and Nd: YAG laser temporomandibular joint arthroscope: development and preliminary clinical findings

This study evaluated the development and preliminary results of a single-channel thin-fiber and Nd:YAG laser temporomandibular joint arthroscope. No articular damage from the arthroscopic procedure and laser lysis was observed in any of the joints when the arthrotomy was performed. All three disk perforations found by the arthroscope were confirmed at the time of the arthrotomy, and in these joints the tip of the arthroscope could be advanced into the inferior joint. The nine joints, where only arthroscopic laser lysis was performed, were followed up and the results were satisfactory.

Osteochondroma of the mandibular angle: Report of a case

Osteochondroma is most often observed near the ends of the long bones. 1,2 In the oral and maxillofacial region, cases of osteochondroma have been reported in the condyle or the coronoid process of the mandible. However, osteochondroma of other areas of the mandible is rare. Only one case of osteochondroma arising in the symphyseal region has been reported by Allan et al. 3 This is the first known reported case of osteochondroma of the inner aspect of the mandibular angle.

Closed reduction of chronic bilateral temporomandibular joint dislocation: A case report

Attempts at manual reduction under general anesthesia of a chronically dislocated temporomandibular joint were unsuccessful. Light elastic traction was applied to modified dentures, and after 7 weeks the condyles were partially repositioned. Without further active reduction, the condyles were fully reseated by 9 months.

Primary Treatment for Osteoarthritis of the Temporomandibular Joint by Combination Therapy of Arthrocentesis, Mouth Opening Exercises, and a Non-steroidal Anti-inflammatory Drug Regimen

Abstract Purpose: To analyse the effect of primary treatment of osteoarthritis of the temporomandibular joint by a combination of arthrocentesis, range of motion exercises, and non-steroidal anti-inflammatory drugs for 12 weeks. Patients and Methods: Fifty patients with osteoarthritis of the temporomandibular joint and unilateral moderate or severe temporomandibular joint dysfunction underwent arthrocentesis and steroid injection followed by mouth opening exercises and oral administration of non-steroidal anti-inflammatory drugs. Therapy continued for 12 weeks, or was stopped earlier if symptoms improved. Patients were evaluated every 2 weeks by visual analogue scales for pain at rest, pain with mandibular motion, pain on chewing and interference with daily life, and measurement of maximal mouth opening. Results: All visual analogue scale values were statistically reduced and maximal mouth opening statistically increased from 32 to 40 mm with this combination therapy. The improvement rates at 2, 4, 6, and 8 weeks after the start of therapy were 46%, 62%, 70%, and 72%, respectively. However, there was no difference between the 10th and 12th weeks, which both showed 76% improvement. Conclusion: This combination therapy is an effective primary treatment for osteoarthritis of the temporomandibular joint. The follow-up period should be 10 to 12 weeks to reach maximum improvement.