Yoritaka Yotsui

Magnetic resonance imaging of the temporomandibular joint: a study of inter- and intraobserver agreement

ObjectiveThe purpose of this study was to estimate the inter- and intraobserver agreement for interpreting magnetic resonance (MR) images of the temporomandibular joint (TMJ).MethodsThe study was based on MR images of 30 TMJs. The images were interpreted by seven observers for disk configuration, disk position, joint fluid, bone marrow changes, and diagnosis. The observers were not calibrated. Kappa statistics were used.ResultsThe kappa values were, for interobserver agreement of disk configuration, 0.10; for disk position in the sagittal plane with closed mouth, 0.35; for a combination of closed mouth and open mouth, 0.44; for disk position in the coronal plane, 0.17; for joint fluid, 0.36; for bone marrow changes, 0.01; and for diagnosis, 0.39. Intraobserver agreement was generally higher than interobserver agreement.ConclusionAgreement on disk position in the sagittal plane, on presence and amount of joint fluid, and on diagnosis was fair to moderate. Agreement on disk configuration, on disk position in the coronal plane, and on bone marrow changes was poor.

Phase I/II Trial of Autologous Bone Marrow Stem Cell Transplantation with a Three-Dimensional Woven-Fabric Scaffold for Periodontitis

Regenerative medicine is emerging as a promising option, but the potential of autologous stem cells has not been investigated well in clinical settings of periodontal treatment. In this clinical study, we evaluated the safety and efficacy of a new regenerative therapy based on the surgical implantation of autologous mesenchymal stem cells (MSCs) with a biodegradable three-dimensional (3D) woven-fabric composite scaffold and platelet-rich plasma (PRP). Ten patients with periodontitis, who required a surgical procedure for intrabony defects, were enrolled in phase I/II trial. Once MSCs were implanted in each periodontal intrabony defect, the patients were monitored during 36 months for a medical exam including laboratory tests of blood and urine samples, changes in clinical attachment level, pocket depth, and linear bone growth (LBG). All three parameters improved significantly during the entire follow-up period (p < 0.0001), leading to an average LBG of 4.7 mm after 36 months. Clinical mobility measured by Periotest showed a decreasing trend after the surgery. No clinical safety problems attributable to the investigational MSCs were identified. This clinical trial suggests that the stem cell therapy using MSCs-PRP/3D woven-fabric composite scaffold may constitute a novel safe and effective regenerative treatment option for periodontitis.

A case of synovial chondromatosis of the temporomandibular joint followed for 17 years.

The patient was a 52-year-old woman who visited our hospital for the chief complaint of a strange sensation in the left temporomandibular joint region on February 22, 1992. On the first examination, crepitus was heard, but no disturbance of mouth opening was noted. On panoramic radiography, radiopaque bodies were present in the left temporomandibular joint region, diagnosed as synovial chondromatosis. Course observation without active treatment was selected. Calcified bodies were noted on the lateral side directly below the left temporomandibular articular tubercle on the first computed tomography image performed in December 1998. Reportedly, this lesion grows slowly, but the lesions started to enlarge at a specific time point during the 17-year follow-up in this patient, showing the necessity of long-term follow-up by imaging even though no quality-of-life reduction or subjective symptom is observed.

Current status of the radiation hygiene on dental radiography in Japan—1984

A nationwide survey was performed to ascertain the frequency of and exposure factors used in dental radiography in 8,000 dental clinics and dental departments of general hospitals throughout Japan. The results obtained were as follows: 1. All dental radiography units in use during this survey employed fixed voltages and currents. For the most part, they used a tube voltage of 60 kV, a tube current of 10 mA and a beam diameter of 6.0 cm or less at cone tip. 2. The total dental radiographic exposures in Japan in 1984 was estimated as 100,181,000; consisisting of 90,878,000 intraoral radiographies; 8,265,000 rotational panoramic radiographies; 390,000 intraoral source radiographies; 323,000 cephalographies; and 325,000 other radiographic techniques. All dental radiography units in use during this survey employed fixed voltages and currents. For the most part, they used a tube voltage of 60 kV, a tube current of 10 mA and a beam diameter of 6.0 cm or less at cone tip. The total dental radiographic exposures in Japan in 1984 was estimated as 100,181,000; consisisting of 90,878,000 intraoral radiographies; 8,265,000 rotational panoramic radiographies; 390,000 intraoral source radiographies; 323,000 cephalographies; and 325,000 other radiographic techniques.SummaryA nationwide survey was performed to ascertain the frequency of and exposure factors used in dental radiography in 8,000 dental clinics and dental departments of general hospitals throughout Japan.The results obtained were as follows:1.All dental radiography units in use during this survey employed fixed voltages and currents. For the most part, they used a tube voltage of 60 kV, a tube current of 10 mA and a beam diameter of 6.0 cm or less at cone tip.2.The total dental radiographic exposures in Japan in 1984 was estimated as 100,181,000; consisisting of 90,878,000 intraoral radiographies; 8,265,000 rotational panoramic radiographies; 390,000 intraoral source radiographies; 323,000 cephalographies; and 325,000 other radiographic techniques.

Current status of the radiation hygiene on dental radiography in Japan—1984—Part 1 hospital and clinic survey

SummaryThe survey of dental X-ray examinations was carried out in the week November 12 to 18, 1984, the contents of the survey being approximately the same as in the 1982 survey. The following points became apparent as a result of the present survey:1)More than 70% of the dental clinics and dental departments of general hospitals were found to require improvements in the available protection from X-rays.2)The use of high speed films and leaded aprons with all patients are two areas where improvements can be readily made.3)The lack of scientific understanding of X-rays on the part of general practitioners appears to be a major stumbling block in improving protection from X-rays.