Necessary diagnostic criteria of dental crowding in children during mixed dentition with different facial skeleton growth patterns

Abstract

Annotation. Pathology of dental crowding during mixed dentition is one of the most common and difficult in the practice of dentist-orthodontist. Its prevalence, according to modern scientific data reaches 77% and occurs in all pathologies of occlusion (malocclusions). The aim of our study is to establish the relationship between the formation of dental crowding and the growth patterns of facial skeleton during mixed dentition in order to improve the effectiveness of orthodontic treatment. We used 42 pairs of plaster models and 42 slices of cone-beam computed tomography images (CBCT) for patients aged 7 to 11 years. Randomization of patients into study groups was performed according to the facial skeleton growth patterns and the Little index value. The analysis was performed by the method of variation statistics taking into account the mean values (mode, median, arithmetic mean) and mean error (M) with the assessment of reliable values by Student’s t-test, as well as determining the correlation coefficient using the Pearson pairwise method to detect connections between the obtained indicators at the minimum probability threshold p<0.05 using the statistical package EZR v. 1.35. According to the results of the examined patients: 30 people (71.4%) had a severe degree of dental crowding on both maxilla and mandible (LII> 8 mm.), more often it was associated with the neutral type of growth – 82% (with vertical – 60%). Statistically significant correlations were found between severe degree of dental crowding and vertical and neutral facial skeleton growth patterns (p<0.05). The results of the CBCT study showed that narrowing of the upper pharyngeal airway (UP) according to McNamara was more common in patients with neutral (85%) and vertical (80%) growth patterns with skeletal II and I class malocclusions according to Engle, which were 55% and 35%, respectively. The study revealed that the vast majority of children with dental crowding with different facial skeleton growth patterns had clinically significant disorders of the development of both maxillary and mandibular apical bases and airways which required immediate interceptive orthodontic treatment.