| Objective: The purposes of this study was to evaluate the relationship between the dental arch shape and the basal arch shape of mandibular,to match of the mandibular dental and basal bone arch shape in individual normal occlusion,and to provide references for the clinical treatment.Methods: In accordance with the inclusion criteria,Experimental Samples with individual normal occlusion(19-27 years)were selected from Xiamen Medical College and took 3D images using CBCT.And then all dates were imported into the Mimics software where to make the 3D-reconstruction of mandibles and dentitions.1.50 samples with individual normal occlusion were selected as the first part experimental subjects.Each sample needs to identify the CC point from the crown and the AP point from the basal bone and were generated three-dimensional coordinates accordingly.After calibration of the sample coordinate system,two-dimensional processing of the references points were to get measuring points and coordinates.In the X-Y plane,the width and length of the dental and basal arch were measured.The Pearson correlation coefficients between references were calculated,and regression analysis were analyzed.Mathematical models of the dental and basal arch were obtained by a mathematical analysis software.Beta function and the fourth-degree polynomial function were respectively used to fit the dental arch and basal arch.To analyze the degree of the function fits of two different functions and the degree of the function fits to the dental arch and basal arch using each function.In the Y-Z plane,the relationship between the arch height and corresponding tooth position was analyzed and to compare differences of the arch height in different tooth position using variance analysis.2.10 samples with individual normal occlusion were selected as the second part experimental subjects.The method of the first part experiment was used to fit the ideal arch curve which was compared with the actual dental arch curves.SPSS 25.0 software was used to test,α = 0.05.Results: 1.There was a significant linear relationship between the length and width of mandibular base bone dental arch(P<0.05),The overall effect of linear regression equation is remarkable(P<0.05).2.In fitting degree of the fourth-degree polynomial function,the base arch was 0.996±0.004,the dental arch was 0.989±0.008.In fitting degree of the β function,the base arch was 0.981±0.012,the dental arch was 0.941±0.025.The results showed that there were significant differences(P<0.05).Fitting degrees of the fourth-degree polynomial function to the base arch and dental arch were greater than the β function.There was significant difference in the fitting degree of the fourth-degree polynomial function and the β function between the base arch and the dental arch(P<0.05).The fitting degree of two functions to the base arch were greater than and dental arch.3.The composition ratio was analyzed at the dental arch height in the same tooth positions.The results showed that the ratio of the maximum height at the canine,the first premolar,the second premolar and the first molar was 36%,20%,36%,8%.Variance analysis showed that there was no significant difference in arch height between different tooth positions(P>0.05).4.The matching degree between the ideal and actual dental arch curves was analyzed and the results showed that the matching degree was high.Conclusion: 1.There was a matching relationship between the mandibular arch and the basal arch of individual normal occlusion.2.The ideal arch curve based on the base bone has a high fitting degree,which can be used for clinical personalized arch manufacture,the design and location of digital dental arch. |
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