Training and Calibration Exercise Using T-bar Gauge and Two-tip Compass

Objectives: To train and calibrate two (2) dental examiners using the T-Bar Proportion Gauge and Two-Tip Compass to measure clinical tooth size proportions (width/length) of maxillary anterior teeth, as preparation for a clinical study to determine aesthetic and functional tooth size proportions.
Methods: Prior to the training and calibration exercise, 15-35 year-old subjects were assessed to confirm the inclusion criteria. A total of 16 individuals were selected (8 female and 8 male). The maxillary anterior dentition encompassing the central incisors, lateral incisors, and canines (left and right) were measured in millimeters at the widest mesial-distal width and the incisal-cervical length using the T-Bar Gauge and Two-Tip Compass. All measurements were performed using dental loupes (2.5x magnification) and headlights. Kappa and Weighted Kappa was calculated for the T-Bar Gauge measurements to determine inter- and intra-examiners agreement. Pearson Correlation was calculated for the Two-Tip Compass measurements. Approximately, 25% of the calibration participants were re-examined to determine intra-examiner reproducibility.
Results: Inter-examiner reliability (Cohen’s weighted Kappa) using the T-Bar Gauge was 0.81. Intra-examiner reproducibility ranged from 0.85-0.90 (Wt Kappa). Inter-examiner reliability (Pearson Correlation Coefficients) using the Two-Tip compass was 0.97. Intra-examiner reproducibility ranged from 0.98-0.99.
Conclusions: Examiners achieved substantial agreement (inter- and intra-examiners) using T-Bar Gauge and Two-Tip Compass to determine aesthetic and functional tooth size proportions.