Online Event 12-14 Nov 2020

15th CAD/CAM & Digital Dentistry Conference

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The Accuracy, Reproducibility, and Reliability of Measurements Obtained from Conventional Plaster Dental Models versus Digital Dental Models


CEREC Ortho software 1.2.1 (Dentsply Sirona, USA) is new in the market, evaluation of its performance is warranted. Our study evaluate the accuracy, reliability, reproducibility, efficacy and effectiveness of measurements of CEREC.


An experimental lab-based study was conducted at the dental laboratory of College of Dentistry at King Saud Bin Abdulaziz University for Health Sciences in Riyadh, Saudi Arabia. Atypodont (D85SDP- 200; Kilgore International Inc, Coldwater, Mich) was used to produce 20 stone models (10 maxillary and 10 mandibular). Those models were scanned by three independent operators twice at two time intervals. The scanned models and the conventional plaster dental models were measured in different planes; anterior-posterior, transverse, and vertical. All measurements were repeated twice for each method by each operator. Each set of measurements was timed and recorded. data were analyzed using SPSS 23 software. A paired t-test, ANOVA, and correlation analysis were used to compare measurements.


Only four variables of the electronic digital caliper measurement method showed poor correlation compared to seven variables of the scanner method. The measurements obtained from scanner is not highly correlated as the ones obtained from the digital caliper.

The means of the anteroposterior (x-axis), transverse (y-axis), and vertical (z-axis) tooth movements of the two methods differed significantly. The correlation analysis revealed that the values of all the variables were fluctuating (highest [0.99] for the y- axis movement; inter-molar, inter-premolar, and inter-canine width and lowest [-0.10] for the z-axis movement of the left canine). No significant difference (p> 0.05) of the time needed during the scanning process in the first (2.760.99) and second (2.631.62) recording.

The mean time required for obtaining the measurements by the electronic digital caliper was significantly less in the second readings than in the first readings ( 3.230.59 Vs 2.780.59, P< 0.001). However, there was no significant difference (P>0.05) when assessing the measurements obtained by using the scanner in the two readings (4.381.38 Vs. 4.131.51).

Both the first and second reading times were less when comparing the electronic digital caliper measurements to the scanner measurements ( R1 = 3.230.59 Vs. 4.381.38, R2= 2.780.42 Vs.4.131.51). 


These results highlight the question of the validity and accuracy of teeth measurement obtained clinically among orthodontists to perform space analysis. As the results show poor inter and Intra operator correlation especially for smaller values. Interestingly when the distance measured are higher in value the inter and intra operator variation is significantly reduced. The fact that all these measurement are solely reliant on the the human factor to detect the points and measure the distances are the main reason behind these variants. We could conclude that human measurement varies significantly and inverse correlation exist with the distance measured. Studies that rely on human obtained measures might be challenged, Further research is needed to evaluate the accuracy of 3D scanner and printer utilizing superimpositions 3D software. 

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