J Adv Prosthodont.  2023 Dec;15(6):281-289. 10.4047/jap.2023.15.6.281.

Prediction accuracy of incisal points in determining occlusal plane of digital complete dentures

• Kashiwazaki K
• Komagamine Y
• Namano S
• Park JM
• Iwaki M
• Minakuchi S
• Kanazawa M

• KMID: 2550269
• DOI: http://doi.org/10.4047/jap.2023.15.6.281

Abstract

PURPOSE
. This study aimed to predict the positional coordinates of incisor points from the scan data of conventional complete dentures and verify their accuracy.
MATERIALS AND METHODS
. The standard triangulated language (STL) data of the scanned 100 pairs of complete upper and lower dentures were imported into the computer-aided design software from which the position coordinates of the points corresponding to each landmark of the jaw were obtained. The x, y, and z coordinates of the incisor point (X_P , Y_P, and Z_P ) were obtained from the maxillary and mandibular landmark coordinates using regression or calculation formulas, and the accuracy was verified to determine the deviation between the measured and predicted coordinate values. Y_P was obtained in two ways using the hamularincisive-papilla plane (HIP) and facial measurements. Multiple regression analysis was used to predict Z_P . The root mean squared error (RMSE) values were used to verify the accuracy of the X_P and Y_P . The RMSE value was obtained after crossvalidation using the remaining 30 cases of denture STL data to verify the accuracy of Z_P . RESULTS. The RMSE was 2.22 for predicting X_P . When predicting Y_P , the RMSE of the method using the HIP plane and facial measurements was 3.18 and 0.73, respectively. Cross-validation revealed the RMSE to be 1.53. CONCLUSION. Y_P and Z_P could be predicted from anatomical landmarks of the maxillary and mandibular edentulous jaw, suggesting that Y_P could be predicted with better accuracy with the addition of the position of the lower border of the upper lip.

Keyword

Automation; Incisor point; Anatomical landmarks; Digital complete dentures; CAD