Consistency and Reliability Analyses of a Comprehensive Index for the Evaluation of Teeth Alignment Performance.

Andrea Mapelli,Alberto Caprioglio,Carolina Dolci,Chiarella Sforza,Marco Serafin,Daniele Gibelli,Gianluca Martino Tartaglia

doi:10.3390/jcm11041016

Abstract

(1) Introduction: The purpose of this work was to describe a method and propose a novel accuracy index to assess orthodontic alignment performance. (2) Methods: Fifteen patients who underwent orthodontic treatment using directly printed clear aligners were recruited. The study sample included 12 maxillary and 10 mandibular arches, whose pre-treatment, predicted and post-treatment digital models were superimposed on the untreated posterior teeth by means of a best-fit surface-based registration, which was also used to transfer three anatomical landmarks, digitally labeled on the crown of each anterior moving tooth, from the pre-treatment to the predicted and post-treatment models. The Teeth Alignment Performance (TAP) index, quantifying how close the final landmarks were to their expected final position, was proposed as an accuracy index of both individual tooth and group of teeth movement, and its inter-examiner repeatability was tested. (3) Results: No systematic inter-rater discrepancy associated with TAP was observed (p > 0.05), not even when a slight systematic inter-rater difference in landmark labelling was detected (for the upper central incisors, p < 0.001). In addition, all Intra-class Correlation Coefficient (ICC) values showed excellent inter-rater agreement (>0.95), and the small Random Error of Measurement (REM), ranging from 1% for the arch TAP to 3% for the lower canine TAP, indicated that this accuracy index is highly repeatable. (4) Conclusions: The TAP index was proven to be comprehensive, consistent and reliable in assessing the performance of teeth alignment according to a digital plan. The proposed method is also suitable to be implemented in the clinical digital workflow.

Highlights

Three-dimensional (3D) digital dental models and procedures have become widely used in orthodontics
The Teeth Alignment Performance (TAP) index, quantifying how close the final landmarks were to their expected final position, was proposed as an accuracy index of both individual tooth and group of teeth movement, and its inter-examiner repeatability was tested
The proposed method is suitable to be implemented in the clinical digital workflow

Summary

Introduction

Three-dimensional (3D) digital dental models and procedures have become widely used in orthodontics. Among the most widely used are the American Board of Orthodontics Objective Grading System (ABO-OGS) score, the Peer Assessment Rating (PAR) score, the Index of Complexity Outcome and Need (ICON) and the Dental Aesthetic Index (DAI) [3]. These indices evaluate both quantitative and qualitative occlusal features, the latter of which partially reduce the objectivity of the measurements; these features are differently weighted and summed to provide a final score, according to elaborate protocols [4,5]. Some researchers [6,7] still use the Irregularity Index [8], a simpler technique that measures the occlusal projection of linear distances between anatomical contact points of adjacent teeth, though its use has been questioned in terms of effectiveness [9], accuracy [10], and repeatability [11]

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