Validity And Reliability Of The 3D Digital Models Of Full Dentition Got By Spiral CT And Cone Beam CT

In dentistry, it was significant to obtain the 3D data of patients'full dentition accurately and efficiently. And, measuring the extracted teeth and the plaster models of dentition were the custom methods. With the development of imaging tools and modeling technique, new methods came out. Spiral CT and CBCT were same to be the main ways in the fields. So far, by spiral CT and CBCT, there were only a few studies on the reconstructions and measurements of these digital models of dentition and no report on the angular measurements.In the study, the 3D digital models of ten youth volunteers'full dentition were got by spiral CT and CBCT, respectively. Then, to testify the validity and reliability of these models qualitatively and quantitatively, systemic linear and angular measurements were done on them. Our study was on the aim to investigation the best imaging methods for obtaining the morphology data of full dentition, clinically,accurately and efficiently. The results showed that:1.1 All the sharps,ridges,fossaes and grooves of the teeth on the plaster models of full dentition were clear. The crowns were intact and the heights of contours were determined.1.2 The reliability of the plaster models were both high in linear and angular measurements. The minimum values of p were 0.143 in linear and 0.215 in angular; the maximum mean differences were -0.06mm in linear and 0.67°in angular.2.1 All the sharps,ridges,fossas and grooves of the teeth on the digital models of dentition got by spiral CT were basically definition. However, there were defects on the crowns and the heights of contours can't be determined.2.2 The reliability of the digital models of dentition got by spiral CT were both high in linear and angular measurements. The minimum values of p were 0.106 in linear and 0.141 in angular; the maximum mean differences were 0.09mm in linear and 0.23°in angular.2.3 The validity of the digital models of dentition got by spiral CT were both high in linear and angular measurements. The minimum values of p were 0.076 in linear and 0.110 in angular; the maximum mean differences were 0.16mm in linear and 0.41°in angular.3.1 All the sharps,ridges,fossas and grooves of the teeth on the digital models of dentition got by CBCT were clearer than that got by spiral CT. The crowns were intact and the heights of contours were determined.3.2 The reliability of the digital models of dentition got by CBCT were both high in linear and angular measurements. The minimum values of p were 0.149 in linear and 0.124 in angular; the maximum mean differences were -0.07mm in linear and -0.12°in angular.3.3 The validity of the digital models of dentition got by CBCT were both high in linear and angular measurements. The minimum values of p were 0.113 in linear and 0.276 in angular; the maximum mean difference were 0.08mm in linear and 0.21°in angular.3.4 The reliability of the plaster models and the digital models of dentition got by spiral CT and CBCT were all high. In linear measurements, the plaster models with absolutely maximum mean difference 0.06mm were the best. Then followed by the digital models got by CBCT with absolutely maximum mean difference 0.07mm . The digital models got by spiral CT with absolutely maximum mean difference 0.09mm were the worst. In angular measurements, the digital models got by CBCT with absolutely maximum mean difference 0.12°were the best, then followed by the digital models got by spiral CT with absolutely maximum mean difference 0.23°. The plaster models with absolutely maximum mean difference 0.67°were the worst.3.5 The validity of the digital models of dentition got by spiral CT and CBCT were both high. In linear and angular measurements, the digital models of dentition got by CBCT which absolutely maximum mean difference with plaster models were 0.08mm in linear and 0.21°in angular were better than that of spiral CT which absolutely maximum mean difference with plaster models were 0.16mm in linear and 0.41°in angular.Conclusions:The plaster models were the best in linear measurements and the digital models got by CBCT were the best in angular measurements. Validity and reliability of the digital models got by CBCT were better than that got by spiral CT, both in linear and angular measurements. CBCT was an ideal imaging method for obtaining the digital models and morphology data of full dentition.