A Comparative Study Of Manual Measurement And Digital Measurement Of Orthodontic Models Under Different Crowding Levels

Objective : To evaluate the reliability and accuracy of digital measurement of dental and maxillary models by comparing the results of manual measurement and digital measurement of orthodontic memory models in different degrees of congestion,so as to clarify the application prospect of digital model measurement in clinical work of oral orthodontics.Methods : The plaster casts of the patients who were first diagnosed in the Department of Orthodontics of The First Affiliated Hospital of Bengbu Medical College from September 2020 to September 2021 were selected.The models that met the inclusion criteria were divided into mild(crowding degree≤4mm)and moderate(4mm<crowding degree≤8mm)and severe crowding group(crowding degree > 8mm),represented by groups L,M,and H,respectively.Each group of plaster models was randomly assigned using EXCEL software,and the serial numbers were selected from 1 to 10.Finally,10 plaster models of groups L,M,and H were obtained respectively.Three groups of plaster casts were scanned by digital scanner to obtain three groups of digital casts.The plaster models were manually measured with vernier calipers,and the digital models were measured with corresponding software.The measured data were recorded.The ICC values of three repeated measurements of the two measurement methods were calculated by SPSS23.0,and the differences between the two measurement methods were compared by paired t test.Results : 1.When the same observer measured the same parameter with the two measurement methods,the ICC values of the three measurements of the same parameter were all more than 0.85(0.852 ～ 0.999),and the correlation coefficients of the two measurement methods were all more than 0.8.2.In the L group,the measurements of 14,36,44,46 crown width and maxillary anterior arch length were statistically significant(P<0.05);In the M group,the measurements of crown width,anterior maxillary arch length,and middle mandibular arch length between the 12,13,26,36,45,46 teeth were statistically significant(P < 0.05);In the H group,the measurements of 15,13,12,11,23,36,43,46 crown width and mandibular middle arch length were statistically significant(P<0.05),the differences in the above measurements were not more than 1.0mm,and there was no significant difference in other parameters(P>0.05).3.There was no significant difference in the measurement of maxillary and mandibular crowding between manual measurement and digital measurement in L,M,H groups(P>0.05).4.In group L,there was no significant difference in overbite and overbite between the two measurement methods(P>0.05);In groups M and H,there were significant differences in overbite measured by the two methods(P<0.05),the measurement difference did not exceed 1.0mm,but there was no significant difference in measurement coverage(P >0.05).5.There was no significant difference in measurement time between the two measurement methods in group L(P > 0.05);There were significant differences in measurement time between the two measurement methods in group M and group H(P<0.05).Conclusion:The use of digital model for measurement in orthodontic clinical work has high reliability and accuracy,which improves clinical work efficiency,saves the storage space of plaster model,reduces the damage rate of model,and provides a more efficient and convenient working method for orthodontic clinical work.