| Budget Amount *help |
¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 2001: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2000: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1999: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Research Abstract |
The morphological characteristics of the roots of the post-canine teeth of squirrel monkeys (Saimin) were investigated. Materials used were 98 skulls and their extracted teeth.
Maxillary molars had three roots, two buccal and one lingual, which arose from a common root.trunk. The roots were often fused in the distal molars, with the buccal roots most often fused to each other. When the maxillary molars had three roots, the interradicular dentine process running between them was Y- or T-shaped ; when they had two roots, it was a straight line. The root structure of M3 had a more reduced pattern than those of M1 and M2.
The mandibular molars had mesial and distal roots. These two roots sometimes fused completely in M3. When the fusion of the two roots was slight, it occurred on the lingual side, but not on the buccal side, and it was gutter-shaped. The gutter-shaped root was most frequently found in M2.When the mandibular molars had two separated roots, the interradicular dentine process was a straight line. Maxillary permanent premolars had the most commonly two roots, one buccal and one lingual, while in more than half of the cases P2 had a single root. Of the maxillary deciduous teeth, dp2 had a single root, but dp3 and dp4 had three roots, two buccal and one lingual. The dp4 teeth resembled M1 in both crown and root structures, but dp4 had more flared and slenderroots than Ml. Most of the mandibular permanent premolars had a single root. Of the P4 teeth, 31.6% had bifurcated roots situated mesiodistally and had a well-developed talonid. The mesial mandibular deciduous premolars had only dne root, as did their successors. The dp4 teeth had both mesial and distal roots, a pattern identical to M1.
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