Kosuke Honda

Correlation between MRI evidence of degenerative condylar surface changes, induction of articular disc displacement and pathological joint sounds in the temporomandibular joint

OBJECTIVES The relationship of bony changes in the condylar surfaces in articular disc displacement without reduction in temporomandibular joint (TMJ) was investigated using diagnostic imaging. The study also evaluated whether the bony changes in the condylar surfaces limit disc and condyle motion, and produce pathological joint sounds. MATERIALS AND METHODS Thirty-seven joints in 28 patients diagnosed with degenerative bony changes in the condylar surfaces radiographically and anterior disc displacement without reduction using magnetic resonance imaging (MRI) were studied. The bony changes were assessed by radiographic examination and classified into two types: pathological bone changes (PBCs) including erosion, osteophyte formation and deformity, and adaptive bone changes (ABCs) including flattening and concavity. MRI was performed on the TMJ to examine the configuration and position of the discs. Joint sounds in the TMJ were determined using electrovibratograghy with a joint vibration analysis. RESULTS The articular disc motion to the condyle in the PBC group was smaller than in the ABC group irrespective of the configuration of the disc, even though there were no significant differences between the two types of bony changes in the disc position during jaw closing. The joint vibration analysis of the TMJ showed that joint sounds with a higher frequency were observed in the PBC group than in the ABC group. High energy levels needed to produce the higher frequencies (over 300 Hz) were observed only in the PBC group.

Causes of Persistent Joint Pain After Arthrocentesis of Temporomandibular Joint

PURPOSE The present study was undertaken to elucidate the factors responsible for the failure of arthrocentesis to cure persistent joint pain in patients with nonreducing articular disc displacement in the temporomandibular joint (TMJ). PATIENTS AND METHODS Thirty-six patients with internal derangement of the TMJ were selected. Magnetic resonance imaging was used to examine the configuration and position of the articular discs, cortical changes, and bone marrow abnormalities in the condyle and the presence of joint effusion. Arthrocentesis was then performed, and the patients were followed for 6 weeks. The results were then classified as poor or improved. RESULTS The effects of arthrocentesis did not depend on the configuration of the disc, disc position and motion, or bone marrow abnormalities. Joints with no or minimal amounts of joint effusion achieved a good response to arthrocentesis. Joints with erosive cortical changes of the condyle were less responsive to arthrocentesis. CONCLUSION Persistent joint pain after arthrocentesis is generally associated with extensive amounts of joint effusion or erosive cortical changes of the condyle.

Allergy to metal caused by materials used for intermaxillary fixation: Case report

A 21-year-old man with no history of contact allergy developed eczema over his entire body 2 days after he had had intermaxillary fixation (IMF) of a mandibular fracture. Patch testing showed a strong reaction to nickel so the arch bars and wires that had been used for fixation were removed and replaced with resin brackets, elastic bands, and a chin cap. The eczema disappeared 2 days later.

Comparison of joint pain in patients diagnosed with and without articular disc displacement without reduction based on the Research Diagnostic Criteria for Temporomandibular Disorders.

OBJECTIVE We compared joint pain (JP) in patients diagnosed with and without articular disc displacement without reduction (ADD) based on the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) and identified the characteristics of each JP. STUDY DESIGN Fifty-eight patients with restricted mouth opening and pain in temporomandibular joint (TMJ) and with a magnetic resonance imaging diagnosis of ADD were selected. Diagnosis of ADD + JP and nonADD + JP was made with the use of the RDC/TMD. RESULTS A multiple regression analysis of the data disclosed a positive correlation between range of motion on maximum assisted mouth opening and visual analog scale (VAS) (severity of JP) in the ADD + JP group, and between chronic pain grade (CPG) and VAS in the nonADD + JP group. A significant difference was observed between ADD + JP and nonADD + JP groups in CPG; CPG was higher in the nonADD + JP than in the ADD + JP group. CONCLUSIONS It is suggested that JP related and unrelated to ADD can indicate different types of disease.

Evaluation of the role of splint therapy in the treatment of temporomandibular joint pain on the basis of MRI evidence of altered disc position

OBJECTIVE To clarify whether altering temporomandibular joint (TMJ) condyle and disc positions by occlusal splint (splint) therapy relieves TMJ pain and to determine whether splint therapy facilitates improvement of the ranges of condyle and articular disc motions. STUDY DESIGN A total of 150 joints of 75 patients admitted with TMJ pain/discomfort were evaluated. A visual analog scale for TMJ pain was administered during visits following the start of splint treatment. At the start of splint treatment, MRI was performed with/without splint insertion, after which condyle/disc movements were evaluated. Disc position and function, disc configuration, joint effusion, osteoarthritis, and the bone marrow were evaluated. Pearsons correlation coefficients, linear regression, and multiple regression analyses were used for statistical analysis. RESULTS Splint-related anterior movement of the condyle was related to TMJ pain. With a biconvex disc and/or bone marrow abnormality, splint treatment was ineffective for reducing TMJ pain. CONCLUSION Splint therapy was not likely to be successful for any kind of TMJ abnormalities, such as bone marrow abnormalities and/or a biconvex disc appearance on MRI.

Prevalence of temporomandibular disorders among junior high school students who play wind instruments.

OBJECTIVES This study investigated whether playing wind instruments has adverse effects on musculoskeletal functions among junior high school students who play in music clubs. MATERIAL AND METHODS The study included 210 junior high school students (35 boys, 175 girls) belonging to 1 of 4 different school clubs that practiced playing wind instruments more than 6 days/week. The mean age of the participants was 14 years. The study was performed using a questionnaire survey and an electromyographic examination of jaw and cervical muscle activities during playing wind instruments. RESULTS The prevalence of temporomandibular disorders (TMD) among the children playing woodwind (WW) or brass wind (BW) instruments was higher than in those playing non-wind (NW) instruments. Long duration of playing WW with a reed mouthpiece or BW with a small mouthpiece was suggested to affect the incidence of TMD, which was more marked in girls than in boys, irrespective of height or weight. Muscle activity in the masseter muscle during playing an instrument was significantly higher in the BW with a small mouthpiece group than in the NW group (p < 0.05). In cervical muscles, muscle activity of both the sternocleidomastoid and trapezius muscles was higher during playing BW than in the case of other instruments, and activity in the sternocleidomastoid muscle was significantly higher in the BW with a small mouthpiece group than in the case of other instrument groups (p < 0.05). CONCLUSIONS Playing wind instruments may have adverse effects on musculoskeletal functions among junior high school students playing in music clubs as compared with playing NW instruments. The prevalence of TMD among the students playing wind instruments was higher than in those playing other instruments. Long duration of playing those instruments affects musculoskeletal function, and this effect is more marked in girls than in boys, irrespective of height or weight.

Clinical study of splint therapeutic efficacy for the relief of temporomandibular joint discomfort

PURPOSE This study aimed to evaluate the relationship between displacement of the mandibular condyle/disc due to occlusal splint insertion with splint therapy and changes in discomfort of the temporomandibular joint (TMJ), and to clarify the relationships between the outcomes over time of temporomandibular discomfort and TMJ magnetic resonance imaging (MRI) findings at the initiation of splint therapy. MATERIALS AND METHODS A total of 75 patients admitted to hospital with discomfort around the TMJ were evaluated. A visual analogue scale for TMJ discomfort was administered during visits for approximately 3 months following the initiation of splint therapy. At the start of splint therapy, magnetic resonance imaging (MRI) was performed with and without splint insertion, and condyle and disc movements were evaluated. Disc balance, disc position and function, disc configuration, joint effusion, osteoarthritis, and bone marrow were evaluated. Linear regression and multiple regression analyses were used to clarify relationships between changes in discomfort and the factors evaluated. RESULTS There was no significant correlation between TMJ discomfort and condyle/disc movement with splint insertion. TMJ discomfort was significantly relieved by splint therapy regardless of temporomandibular MRI findings. Unilateral anterior disc displacement and marked or extensive joint effusion fluid were significantly improved with splint therapy. CONCLUSION Discomfort tended to remit with splint therapy regardless of temporomandibular MRI findings. Improvement of TMJ discomfort appears more likely to occur in patients with unilateral anterior disc displacement and with an apparent organic disorder, such as a joint effusion.