Masahiko Funato

Effects of jaw clenching while wearing an occlusal splint on awareness of tiredness, bite force, and EEG power spectrum

PURPOSE Treatment with an occlusal splint is used for temporomandibular disorders, bruxism, and occlusal disturbance to relieve orofacial symptoms such as myofascial pain and jaw movement restriction. However, the effects of various types of occlusal splints have not been elucidated. We investigated the effects of jaw clenching with soft and hard occlusal splints on the awareness of tiredness, bite force, and EEG activity. METHODS Six healthy adults were used as subjects, with a visual analogue scale utilized to evaluate the awareness of each patients tiredness both preceding the session and following the clenching trials. In addition, a Dental Prescale was used to measure bite force and an EEG recording was conducted while performing jaw clenching. The jaw clenching task comprised 1min of maximal voluntary clenching under 3 kinds of clenching conditions: with natural dentition, and with soft and hard occlusal splints, which were each repeated 5 times. RESULTS Jaw clenching with natural dentition and a hard occlusal splint did not cause a significant awareness of tiredness following repetitive jaw clenching, and there was not a significant alteration of EEG spectrum values with those conditions. In contrast, jaw clenching with a soft occlusal splint caused a significant increase in awareness of tiredness, as well as significant decreases in bite force and EEG alpha 2 power spectrum values. CONCLUSIONS Jaw clenching with a soft resilient occlusal splint causes an awareness of tiredness, which might be accompanied by declines in bite force and EEG spectrum values.

Modulation of occlusal comfort accompanying with pain and anxiety and depression mood states

Abstract: Pain and tactile sensation have an interactive relationship, i.e. pain inhibits or facilitates tactile sensation, while tactile sensation inhibits pain sensation. Therefore, TMDs are generally given for pain disorders in the orofacial region that are possibly related to occlusal discomfort. Also, it is clinically reported that psychiatric distress possibly affects to the occlusal discomfort. In this study, we attempted to clarify the relationships between awareness of occlusal comfort and TMD symptoms such as TMJ-noise, TMJ-pain, and jaw movement difficulty, as well as occlusal and psychiatric conditions. The subjects were 135 students. First, we examined TMD symptoms using a diagnostic process composed of an interview and examination, then we classified the subjects into 3 groups; non-symptomatic (n=69), TMJ-noise (n=45), and jaw movement related TMJ-pain (n=21). In a comparison with the non-symptomatic group , the results of a numerical rating scale (NRS) showing the awareness of TMD symptoms indicated that those with jaw movement related TMJpain had significantly aggravated awareness of TMJ-noise, jaw movement related TMJ-pain, and jaw movement difficulty, while the TMJ-noise group had significant aggravated awareness of jaw movement related TMJ-pain and jaw movement difficulty. In addition, subjects with jaw movement related TMJ-pain had a significant decrease in awareness of occlusal comfort demonstrated in NRS findings as compared with the non-symptomatic group, even

Measurement Accuracy of Condylar Position on Corrected Lateral Tomography of Temporomandibular Joint with Scanora Multimodal Radiography.

Accurate measurement of the condylar position is important for diagnosis and treatment of temporomandibular joint (TMJ) dysfunction. Radiography has been used for this purpose and recently, Scanora® multimodal radiography was introduced to Showa University. The projection capacity of the Scanora® in TMJ is still unclear. The purpose of this study was to estimate the accuracy of the measurement of the condylar position on sagittal tomography with Scanora® and to compare Scanora® images with LGM-1 images. Six TMJs obtained from dried skulls were used. Impressions of the joint space were obtained in order to estimate the actual dimensions. The Scanora® images, LGM-1 images, and impressions were measured with a profile projector. The results were as follows: 1) The measurement error of condylar position on Scanora® with a mean value of 0.29mm was similar to that on LGM-1 (0.25mm). 2) The measurement errors on both images in 1 of 6 TMJs were especially great (Scanora: 0.72mm, LGM-1: 0.87mm) while the measurement of the other 5 TMJs on both images showed smaller mean errors (Scanora: 0.2mm, LGM-1: 0.12mm). Therefore, there may be a considerable value of errors in the measurement on both images in the case of particular morphological types of joints. 3) It showed that the measurement errors of Y coordinates were larger than those of X coordinates. 4) The projection grade of both images were similar. These results suggested that sagittal tomography on Scanora® is useful for clinical estimate of the condylar position.