It is well known that the anatomy of the masticatory muscles is related to craniofacial morphology. We evaluated the relationship between the volume and inclination of the medial pterygoid muscle and craniofacial morphology in subjects with normal occlusion. Muscle volume correlated with FMA, gonial angle, saddle angle, the angle of convexity, SN-GoGn and posterior facial height. Muscle inclination correlated with FH-SN, saddle angle and articulare angle. The asymmetry index of muscle inclination in subjects whose mandible tipped away from the membrum correlated with the Ag line angle and distance ORP to Me.
     When viewed in the sagittal plane, the volume and inclination of the medial pterygoid muscle affected the position of the mandible and the mandibular fossa. When viewed in the frontal plane, the relationship between the medial pterygoid muscle and craniofacial morphology depended on displacement of the mandible.

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Anteroposterior movement (AP) and opening and closing (OC) of the mandible are accompanied by a gliding movement of the condylar head that is controlled primarily by the lateral pterygoid muscle. We investigated differences in the electromyography of the lateral pterygoid muscle before and after treatment in patients with a closed lock.
     The muscular activities during AP and OC movements were determined in each patient and OC/AP ratios were calculated and compared. When we compared the ratios, we found a significant difference between the affected and healthy sides in patients with closed lock, but not in patients after functional recovery. A significant difference was noted between the affected side of patients before and after treatment.
     These findings suggest that functional recovery of condylar head movement can be evaluated based on the OC/AP ratio of the lateral pterygoid muscle.

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Using a three-dimensional finite element model, I investigated how use of the chin cap affected the distribution of stress in the mandible and temporomandibular joint. Dried human skulls were used to create the three-dimensional finite element model. Different directions of traction force that might be applied by the chin cap were input to the model. We found that different directions of traction imparted different stresses on the condyle. Using this model we were able to quantify the distribution of stress in the mandible.

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Cisplatin (CDDP) is a potent DNA-damaging anticancer agent that induces cytotoxic action by induction of apoptosis. However, its underlying molecular mechanisms remain to be elucidated. We examined the activation of caspase-2, which is involved in the induction of apoptosis by CDDP, in relation to Bax translocation and the interaction of cytochrome c release from mitochondria. The human oral squamous cell carcinoma cell line (HSC-4) was employed in this study.
     We found that treatment of HSC-4 cells with CDDP decreased cell viability in a dose-dependent manner, and induced apoptosis. One of the apoptosome molecules, cytochrome c, was significantly augmented in the cytoplasm by CDDP treatment. Activation of caspase-2, -3 and -9 was detected after treatment with CDDP. Furthermore, apoptosis was blocked when HSC-4 cells that had been treated with CDDP were co-treated with caspase inhibitors such as Z-DEVD-FMK, Z-VDVAD-FMK and Z-LEHD-AFC. In addition, caspase-2 inhibitor decreased cytochorome c release and delayed Bax translocation into mitochondria.
     Our results suggest that activation of caspase-2 occurs upstream of the mitochondrial pathway in CDDP-induced apoptosis, and regulates both cytochrome c release and Bax translocation.

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We evaluated the adaptation and dimensional changes in fiber-reinforced composite resin (FRC) bridges fabricated with a hybrid composite resin. Metallic molds were prepared either with square or rounded shoulders. The axial and occlusal surfaces of the die abutments were treated either with no die-spacer or application of one, two or three layers. The test specimens were measured using a three-dimensional scanning system that determined the dimensions of both the outline of the metallic mold and of the inner surface of the abutment prosthesis. The scanning data were adjusted and analyzed using CAD software. Statistical analysis was performed by means of three-way ANOVA with the three factors of die-spacer coating, shape of the preparation and the measurement point location.
     ANOVA analysis demonstrated that all three factors were significant (p<0.01). We were able to determine how the thickness of the die-spacer and the shape of the preparation affected adaptation of the FRC bridges.

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