Linear Accuracy of Full-Arch Digital Models Using Four Different Scanning Methods: An In Vitro Study Using a Coordinate Measuring Machine

Young Hyun Kim,Sang-Sun Han,Chang-Woo Woo,Yoon Joo Choi

doi:10.3390/app10082741

Young Hyun Kim, Sang-Sun Han + Show 2 more

Open Access

https://doi.org/10.3390/app10082741

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Abstract

Improving the accuracy of the digital model is essential for the digitalization of the dental field. This study introduced a novel method of objective accuracy evaluation of digitized full dental arch model using coordinate measuring machine (CMM). To obtain a true linear measurement value using the CMM, 17 reference balls were attached to the typodont, and 12 measurements between balls on the X-(width), Y-(length), and Z-axes (height) were performed automatically. A rubber impression and a plaster cast replica of the typodont with balls were fabricated, and they were digitized with following methods: (a) true model intraoral scans; (b) impression cone-beam computed tomography (CBCT) scans; (c) cast CBCT scans; and (d) cast extraoral scans. Each scanning method was performed 20 times. Twelve linear measurements on the digitized models were automatically made using software. The one-sample t-test and one-way analysis of variance were used for measurement accuracy analysis. The cast extraoral scan was most accurate on X- and Y-axes, while impression CBCT was the most accurate on Z-axis. Over all axes, the intraoral scan resulted in the most deviation from the true model, and the reproducibility of each scan was also low. Extraoral scan shows high precision on width and length, and impression CBCT is advantageous for dental work where height factor is of importance.

Highlights

Digitalization is a recent trend in dentistry, characterized by the development of digital models to replace plaster casts
Since the digital model generation procedure is based on an impression or plaster model, which already involves distortion, the accuracy of the overall digital model should be evaluated based on the gold standard value obtained from the patient’s actual dental arch
In recent years, digitized dental arch models have become a major trend in dentistry

Summary

Introduction

Digitalization is a recent trend in dentistry, characterized by the development of digital models to replace plaster casts. Researchers set the dental cast model or the extraoral optical-scanner-generated digital model as a gold standard to which they compare digital models obtained with different methods to evaluate the accuracy [1,2,3,4]. Since the digital model generation procedure is based on an impression or plaster model, which already involves distortion, the accuracy of the overall digital model should be evaluated based on the gold standard value obtained from the patient’s actual dental arch. In this study, a novel accuracy evaluation method was introduced using CMM and reference balls, eliminating manual error for both the gold standard measurements and the digital models With this method, the accuracy of digital models obtained with all current scanning methods was analyzed based on the true values of dental arch width, length, and height

Fabrication of the

Intraoral Scans

Statistical Analysis

Results

Scanning Method

Discussion