Comparison of Dental Morphometrics of Two Different Patients Using the Program Package - “SHAPE ver.1.3”

Introduction In recent years with progressing digital dentistry, programs that identify teeth from orthopantomograms (OPG) based only on their shape have been developed. This does potentially help clinical diagnostics, however, a more precise way to evaluate anatomical differences is needed. The software package SHAPE which uses Principal Components Analysis (PCA) has proven effectiveness in analyzing and comparing Japanese radish shapes [1]. PCA simplifies complex data by identifying key components, making it easier to compare dental structures [2]. This tool, also, could be more precise since we draw the outer edge of the tooth shape, while older methods draw the bounding boxes around the tooth shape [3, 4]. So, by applying this technique to digitized teeth contours it could be possible to reveal even mikro-differences between different patients with potential applications in diagnostics, forensics, and anthropology [5]. Aim The aim of this study is to evaluate the dental anatomical differences shown in OPG of two different patients using the program package - "SHAPE ver.1.3". Methods Precise quality OPG of two patients, who both had all 32 of their teeth erupted and presented with no pathological radiographic changes, were chosen to be quantitatively evaluated. Firstly, all the contours of the 64 teeth were traced using an image editing software “GIMP 2.10.38”, fitted into a correct format and digitized using "SHAPE ver.1.3" software’s programs: “ChainCoder“, “Chc2Nef“, “PrinComp”, “PrinPrint”. The number of principal components (PC), their eigenvalues and proportion of each PC, means and standard deviation of the PC1 were calculated for each of the teeth. The statistical significance of the differences in anatomy was assessed using the Student's t-test for independent samples, Mann-Whitney-Wilcoxon test. The results of both methods did not differ when assessing the statistical significance. The differences were considered statistically significant when p<0.05. Results The tooth with the highest proportion of PC1 in the first patient was 36 (97.6%), in the second patient - 17 (90.2%). The tooth with the lowest proportion of PC1 in the first patient was 31 (36.7%), in the second patient - 42 (35.6%). Significant differences between patients were observed between the teeth 11 and 21 (PC1 = 39.7; 56.8), 34 and 44 (PC1 = 47.5; 55.9), 38 and 48 (PC1 = 87.1; 67.5) (p<0,05). Conclusions The first patient had slightly higher PC1 values for most teeth compared to the second patient, with some exceptions. That indicated a more mathematically correct dental anatomy of the first patient. Moreover, molars tend to have higher percentages for the PC1, incisors generally show lower proportions. Overall, significant differences in dental anatomy between patients were observed, that is likely attributable to genetic variation between people.