| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1998: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1997: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Research Abstract |
The purpose of this study is to develop a chair-side non-radiographic three-dimensional cranio-dento-facial measuring system. The development consists of three parts. One is equipment arrangement of a clinical dental chair with a head holder, a personal computer and a 3-D digitizer of contact method (Micro Scribe 3D(]SY.encircledr.[)). The second is programming a software that can convert the relative 3-D coordinates of the landmarks in the cranio-dento-facial region into the absolute ones and project them onto the three two-dimensional reference planes (the horizontal plane, mid-sagittal plane and the orbital plane). The obtained angular and linear measurements were expected to be comparable with those obtained by the roentgenographic cephalometry. The third is calibration of the system followed by sample measuring. The system is compact, portable and quite satisfactory in measuring performance. Our original software can bring forth 93 cephalometric angular and linear measurements thr
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ough 3-D digitization of 60 landmarks on the cranio-dento-facial region. The position accuracy of the system digitizer was 0.250 mm in our examination compared with 0.258 mm in the manufacturer's specifications. In calibration using a 10 mm gauge block, our system showed accuracy of * 0.0515 mm while the noted 3-D digitizer, ZEISS UMC-5850(]SY.encircledr.[) as a control (manufacturer's accuracy specification is U<@D295@>D2 2.5+ L/250um) showed * 0.0005 mm. In comparison of the 3-D coordinates obtained by both digitizers for 31 landmarks marked with lead dots on the same human dry skull, the mean absolute difference for each of the coordinates (x, y, z) were 0.2670 mm, 0.3623 mm and 0.1370 mm respectively which were considered minimal. There was no big difference between the cephalometric measurements made by both digitizers, which suggests high reliability of our system as a measurement device. The system can be an effective non-radiographic modality for cranio-dento-facial measurement as far as objects of measurement are appropriately selected. Less
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