Effect of defect size and tooth anatomy in the measurements of a 3D patient monitoring tool

PURPOSE: To assess the influence of defect size and tooth anatomy on the measurements performed by a 3D patient monitoring tool. METHODS: A fully dentate model was scanned to obtain a master digital file. Virtual duplicates received defects created in molars (16, 18, 28) and incisors (11, 12, 22), according to different depths (60, 80, 120 microns) and sizes (small, medium, large) totaling 180 conditions. The surface changes measured by the 3D Patient Monitoring Tool (3Shape TRIOS Patient Monitoring [TPM]) were compared with the reference by 2 calibrated operators. False Positives (FP), and False Negatives (FN) defect were registered. Pearson chi-square test, Multivariate binary logistic regression and Spearman rank correlation were used to evaluate the data (α = 0.05). RESULTS: A significant association was found between the area and the presence of FP and FN (P < .01). Larger defects had higher chances to present FP or an FN respectively. There was a significant association between the tooth and the presence of a FP value (FP, P = .02; FN, P = .005) specially in molars. No significant association was found between the defect depth and the presence of a FP value. Spearman rank correlation showed a strong association between the presence of an FP and an FN (r = 0.858, P < .01). CONCLUSIONS: The defect size and tooth anatomy significantly affected the virtual follow-up, whereas defect depth did not. Small defects were correctly detected in all cases. An incorrect measurement on one side of the tooth simultaneously resulted in incorrect measurement on the opposite side. CLINICAL RELEVANCE: The clinician should be aware that different factors related to the characteristics of the defects could affect the quality of the full-arch digital follow-up. Therefore, caution is needed when interpreting the models comparison in cases that a larger area of a tooth has been modified.