Objectives : The purpose of this study was to develop an experimental carious detector by which only carious-infected dentin is stained and to investigate bacterial invasion after removal of dentin based on staining using the experimental carious detector. Methodology : Micro Vickers Hardness (MVH) of the extracted human teeth was measured on the longitudinal section surface from the pulp chamber to the carious region using a micro hardness tester. The carious dentin was removed based on tactile sensitivity, and based on staining using conventional and experimental carious detectors. The MVH of the remaining dentin cavity wall was determined by observing the indentation beneath the cavity wall. The microstructure of the remaining dentin was observed using a SEM (5-4700, Hitachi, JAPAN) and the possibility of bacteria survival was examined using a Gram stained specimen. Results : The MVH of the remaining dentin cavity wall after removal of the carious dentin (25.5±7.8 : tactile sensitivity, 32.7±8.2 : experimental carious detector, 44.7±6.6 : conventional carious detector) was statistically significantly different by ANOVA with Fisher's PLSD (p<0.001). The dentin tubules of the cavity wall were completely closed with rod-like substances with a cubed structure after the carious dentin was removed using the experimental carious detector. In addition, no bacteria was observed in any of the specimens. Conclusion : It was possible to conclude that the carious-infected dentin was completely removed and sclerotic dentin was preserved under the guidance of the experimental carious detector stain composed of poly-propylene glycol and acid red.

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Clonidine, an α₂-adrenocepter agonist, has often been used for sedation and analgesia prior to surgery. Unfortunately, clonidine usually induces some side effects during surgery, such as low blood pressure and bradycardia. Atropine, a muscarinic receptor antagonist, is used for improving some side effects induced by clonidine action during surgery. It is known in the field of ophthalmology that atropine, as well as clonidine, affects intraocular pressure (TOP). However, effects of simultaneous administration of atropine and clonidine on TOP still remain unclear although these drugs have been used during surgery under general anesthesia. The present study examined the influence of clonidine and atropine on IOP under the condition of anesthesia in the rat.
Male Wistar rats (250-300 g, n=38) were used. Under urethane anesthesia (1.4 g/kg, i.p.), a catheter was inserted into the jugular vein for administrating drugs and into the femoral artery for measuring the mean arterial blood pressure (MBP). For measuring the IOP, an injection needle (27-gauge) was penetrated into the anterior chamber of the eyeball. The heart rate (HR) was recorded from an electrocardiogram. Statistical analysis was carried out using analysis of variance (ANOVA). A difference was accepted as significant when p < 0.05.
Administration of clonidine hydrochloride (5 μg/kg, n=15) significantly decreased the IOP to 81% of the control (100%, before drugs). The MBP and the HR were also significantly reduced 60% and 15% of the control, respectively. Atropine sulphate (60 μg/kg, n=4) significantly increased the HR to 30% of the control, while significant changes in the IOP and the MBP were not observed. Simultaneous administration of clonidine and atropine (n = 7) produced significant decreases of both the IOP and the MBP, whereas no significant change in the HR was observed.
The present study suggests that atropine does not alter IOP under normal conditions and improves bradycardia produced by clonidine without changes in the MBP and the IOP.

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This study investigated the relationship between occlusal contact area (OCA) of the lateral position, masticatory movement path and masticatory rhythm.
Bite impressions of 17 healthy subjects were used to determine the OCA of less than 50 μm in thickness. Three mandibular positions, the intercuspal position (IP), and right and left lateral 1 mm positions from the IP were regulated with an altered extraoral Gothic arch tracer. Mandibular movement was recorded in the frontal plane during 10 strokes to obtain the mean masticatory rhythm and the mean angle of closing path using a Gnatho-hexagraph (GC, Tokyo, Japan). The results showed that changes of OCA occurred when the occlusal biting force increased the IP, the working side and the balancing side. The OCA of the working side and the balancing side 1 mm lateral from the IP showed a significant relationship according to the cusp angle. This relationship was observed in the case of light and strong bite forces. Occlusal contact of the balancing side occurred when occlusal force was increased. Therefore, it is recommended that during the final stage of occlusal adjustment, occlusal contact and cusp angle of the balancing side also need to be assessed.

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Pedicled buccal fat pad is nowadays widely applied for the reconstruction of relatively large defects of the maxilla with satisfactory profits. Here we report a case in which a defect was successfully reconstructed with pedicled buccal fat after a removal of a palatal tumor. An 87-year-old female has visited our hospital complaining a large mass of the palate. The mass was approximately 30 mm in diameter, elastic hard on palpation, with a large necrotic ulcer on its surface. It was strongly suspected as a malignant tumor through the clinical findings and a set of diagnostic imaging. The tumor was dissected under general anesthesia, and a large bone exposure and a soft palate perforation was caused after the tumor removal. A pedicled buccal fat pad was harvested from the right molar mucogingival fold, and the defect was mostly covered with the fat pad graft and tie-over. The histopathologic diagnosis of the lesion was carcinoma ex pleomorphic adenoma. Postoperative progress has been satisfactory without secondary infection, necrosis of the graft, functional disturbances due to a scar formation, oro-antral or oro-nasal communication, and tumor recurrence.

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[in Japanese]

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