| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2004: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2003: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2002: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
In the present study, 318 permanent human tooth crowns were micro-CT scanned and thigh resolution volume data sets obtained. Data analysis focussed primarily on enamel thickness measurements taken in the mesial cusp section of 167 unworn molars. We obtained the following results. Enamel thickness at the cusp tips and occlusal basin in sections slightly offset from the mesial cusp section was found to be inaccurate by up to about 0.5 to 1 mm. We also found that maximum 'radial' thickness of the lateral crown face was least affected by section position, usually with discrepancies of less than about 0.1-0.2 mm. Mid-lateral crown thickness was found to vary by definition of the horizontal reference plane, and thus less useful in evaluating enamel distribution patterns than maximum lateral thickness. In all serial positions in both upper and lower molars, a 'functional' to 'non-functional' side gradient in enamel thickness was observed in cusp tip, occlusal basin, and lateral crown face enamel, with the exception of the characteristically thin enamel at the protoconid and paracone cusp tips. Serial differences in thickness were seen between the thinner M1 and the two posterior molars in many but not all measures of thickness, the pattern of which appears to be influenced by the thin M1 mesiobuccal cusp enamel. Individual variation of maximum lateral thickness, the least variable measure of thickness, was found to be substantial even with serial and buccolingual positions controlled. Correlation between whole crown average enamel thickness and maximum lateral thickness was high, indicating that the latter is a potentially useful predictor of overall enamel thickness of the molar crown.
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