| Co-Investigator(Kenkyū-buntansha) |
SURUGA Yuriko Iwate Medical University, Department of Pediatric Dentistry, assistant, 歯学部, 助手 (70244952)
ABE Eiichi Iwate Medical University, Department of Pediatric Dentistry, assistant, 歯学部, 助手 (60265171)
SATOH Teruko Iwate Medical University, Department of Pediatric Dentistry, assistant, 歯学部, 助手 (70205938)
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| Budget Amount *help |
¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2000: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1999: ¥600,000 (Direct Cost: ¥600,000)
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| Research Abstract |
PURPOSE : In our studies from 1998 to 1999, an attempt to establish the outline form of the cavity was made minimizing microleakage from the margin, without unpolymerized resin leaving behind, keeping the cutting to a minimum amount, and to decide the kind of bar adequate to prepare such a cavity. During the concerned year, since the trial bar as above mentioned had already been made, we performed the cavity preparation in infantile dogs and compared the effects on the pulpal tissues between those prepared with a conventional bar and with the trial bar. MATERIAL AND METHODS : Nine 2-month-old mongrel dogswere used. Under intra-abdominal anesthesia with pentobarbital, tooth cavities of approximately 0.5 mm depth were prepared in the right lower third molars using the trial bar, whereas in the left teeth the cavities were formed with a FG301 diamond bar. Next, a stopping was placed in the floor of these cavities and High-bond Carbo-cement ^<TM> was filled to cover it. At 3, 14 and 28 day
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s after the cavity preparation, mandibles were extirpated and decalcified with Plank-Rychlo solution following fixation. Then, the specimens were dehydrated, embedded in paraffin, cut into 30 μm-thick sections and stained with hematoxylin and eosin. Observation was made on the pulpal tissue changes. RESULTS AND DISCUSSION : At 3 days after the cavity preparation, dilatation of the blood capillaries and disappearance or vacuolar degeneration of the odontoblasts in the proximity of the cavities were observed in both the control and experimental groups. These changes were more significant in the control group. At 14 days, although the vacuolar degeneration of odontoblasts was no more observed, marked inflammatory cell infiltration and capillary dilatation were revealed in the pulpal tissue adjacent to the cavity floor. These changes were also more intensely expressed in the control group. At 28 days, these inflammatory signs still persisted only in the control group. Base on the present results, it is concluded that this experimentally tested bar for the adhesive composite resin is applicable to the clinical usage. Less
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