We report herein a case of occlusal correction performed for intermittent jaw locking in which temporomandibular joint (TMJ) disc repositioning, which was not initially observed after prosthesis placement, occurred during the course of follow-up observation.
At the time of initial examination, the patient could unlock his jaw himself; however, frequent recurrence of locking interfered with daily living and left-sided anterior disc displacement without reduction was diagnosed. While locking did not occur during use of an anterior repositioning splint, discontinuation of the splint resulted in repeated recurrence. Therefore, a reversible process was implemented in which a hard resin adhesive splint was inserted in the mandibular position so that locking did not occur. Magnetic resonance imaging (MRI) performed at the time of splint insertion demonstrated continued anterior disc displacement without reduction; however, as locking did not recur and smooth mandibular movement that did not interfere with daily living was achieved, locking treatment was judged to be completed and crown treatment was commenced. MRI was performed 18 months later and demonstrated that the left-side anterior disc was in the normal position after the prosthesis had resolved. Occlusal stability, which was achieved through crown treatment in the mandibular left molar region, reduced the load on the TMJ. Pain resolution, relaxation of the superior head of the lateral pterygoid muscle and smooth mandibular movement are believed to have facilitated disc repositioning.

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Although the manipulation technique (MAT) is a non-invasive and inexpensive treatment procedure used for the initial treatment of TMD patients with limited mouth-opening, its effectiveness has not yet been confirmed. The aim of this study was to determine the clinical effectiveness of MAT. We quantitatively compared two groups, one using the self jaw exercise (SJE) and MAT, and the other using SJE only. Among TMD patients who visited our clinic, 34 patients whose mouth-opening distance was less than 35 mm were selected as subjects, and were randomly divided into two groups using block randomization. The Jog-Manipulation technique (J-MAT) developed in our clinic was used as MAT. J-MAT has the following three combinations: the pivot closing type, the side-to-side type, and the opening type. Regarding SJE, an improved self exercise was used, in which patients pulled down post molars on both sides using their index finger according to their mouth movement. The degree of pain according to the Numerical Rating Scale (NRS) and mouth-opening distance were recorded at the following five points: (1) before the treatment, (2) after the treatment, (3) at two weeks, (4) at four weeks and (5) at six weeks.
No significant difference between NRS pain scores was observed. Therefore, MAT has no additional effect on mitigating pain. On the other hand, a significant difference in the 2-way ANOVA and multiple comparisons between the mouth-opening distance of MAT and SJE was observed.
The results show that J-MAT is useful for early improvement of the mouth-opening distance in TMD patients with limited mouth-opening.

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Nonsyndromic agenesis of bilateral mandibular condyles is very rare. The present case was a 13-year-old female with the chief complaint of upper protrusion and mandibular retrusion. The degree of mouth opening was 40 mm. The dental arch was parabolic with 12.5 mm of overjet and 2 mm of overbite, and the number of teeth was normal. Panoramic radiograph revealed the absence of mandibular condyles. Lateral cephalogram demonstrated a small mandible. Pharyngeal morphology was found to be normal, and radiographic examination of swallowing showed no obstacles. Jaw movement was observed owing to hypoplasia of the bilateral mandibular condyles. No difference in left- and right-side masticatory muscle activity was detected. Sufficient masseter muscle activity and mastication force were observed. This suggests that functional adaptation had occurred to compensate for the morphological characteristics of the mandibular condyles, although there was no occlusal contact in the anterior tooth area.

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We report the case of an 80-year-old woman with suspected acute suppurative arthritis of the temporomandibular joint (TMJ). The patient visited our hospital because she experienced spontaneous pain in the right TMJ. Examination at the initial visit revealed tenderness in the right TMJ and trismus. Computed tomography (CT) revealed a low-density area within the articular capsule and displacement of the mandibular head to the lower side; these findings led to the diagnosis of acute suppurative arthritis of the TMJ.
The patient received anti-inflammatory drug therapy and performed an exercise to facilitate opening of the mouth. We extracted an impacted tooth which may have been the source of infection. At present, she is clinically healthy.

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The purpose of this study was to examine the effects of a combined treatment program involving short-term simple-splint use and patient education to increase awareness of the damage caused by daytime tooth-clenching (DTC) including a tooth contacting habit (TCH). The use of a simple-splint was not intended to achieve occlusal adjustment. The subjects answered a questionnaire consisting of two questions, one concerning an index of the awareness of DTC, and the other concerning the activities and locations during DTC.
In this study, 49 patients who were suspected of engaging in DTC were given the questionnaire on four separate occasions: (1) at the initial medical examination before patient education; (2) at the initial medical examination after patient education; (3) during the second examination before using the simple-splint; and (4) during the third examination after using the simple-splint.
The results of the four sets of questionnaires were analyzed as repeated measures of ranked data using Friedman's two-way ANOVA. From the first question, the selected numbers were used as an index of the awareness of DTC. Statistically significant differences were found between the first and the third or the fourth (p< 0.01) and the second and the fourth (p< 0.05). From the second question, the total number of locations or situations was used as a parameter. Statistically significant differences were found between the second and the fourth (p< 0.01) and between the second and the third (p< 0.05). Based on these results, it is suggested that a combined treatment program involving short-term simple-splint use and patient education on the awareness of DTC might be an effective means of developing patient awareness of DTC.

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