CORRELATION OF 3D-MORPHOMETRIC FEATURES OF THE DENTOFACIAL SYSTEM IN DISTAL OCCLUSION DURING THE PERMANENT DENTITION PERIOD

Objective. To quantitatively assess the mean mesiodistal crown dimensions of permanent teeth of the maxilla and mandible in adult patients with distal occlusion, to classify the dental type of the dental arches (micro-, normo-, macrodontic) and their arch type (dolicho-, meso-, brachyarch), and to identify correlations between these parameters. Methodology. 268 patients aged 17–35 years with distal occlusion were examined. Linear measurements of the mesiodistal dimensions of the crowns of 14 teeth in each jaw were performed on 3D jaw models (cone-beam computed tomography, KaVo OP300 Maxio system). Dental and arch types were determined. Statistical processing in SPSS 23.0 included calculation of means (M±SD) and Pearson's correlation analysis (p <0.05). Results. The mean total crown dimensions were: maxilla – 109.90 ±4.40 mm, mandible - 103.86 ±5.12 mm. The normodontic type predominated in the maxilla (52.5 %), while the microdontic type prevailed in the mandible (47.5 %). The mean arch index was 0.526 ±0.035 for the maxilla (mesoarch type) and 0.493 ±0.051 for the mandible (dolichoarch type). Distribution of arch types: in the maxilla, dolichoarch – 45 %, mesoarch – 40 %, brachyarch – 15 %; in the mandible – 67.5 %, 25 %, and 7.5 %, respectively. A high positive correlation was found between the total crown width and dental type for both jaws (p <0.001). For the maxilla, a negative correlation was found between the sum of crown dimensions and the arch index (p = 0.01), as well as between the arch index and dental type (p <0.001). For the mandible, these relationships were not statistically significant (p >0.05). Conclusion. The application of 3D odontometry and 3D biometry is highly informative for studying the relationship between tooth size and dental arch dimensions in distal occlusion. The results confirm a close correlation between crown dimensions and dental type and reveal a more pronounced "tooth width - arch width" relationship for the maxilla, which is of practical importance for planning individualized orthodontic treatment.