Biometric parameters of the upper dental arch in patients with a stable result of orthodontic treatment of abnormal position of the crowns of the maxillary canines

Aim – to evaluate the metric parameters of the upper dentition in patients with a stable result of orthodontic treatment of anomalies in the position of the crowns of the upper canines in the long-term follow-up period.

Material and methods. We conducted an open study on a sample of patients after orthodontic treatment using clinical and instrumental methods. We analyzed 126 clinical cases of patients aged from 18 to 44 years with completed orthodontic treatment of abnormal position of the crowns of the maxillary canines with satisfactory aesthetic and functional results. The duration of the retention period ranged from 5 to 10 years. 75 patients met the inclusion criteria for the study.

Results. The study showed that the biometric parameters of the dental arches after the end of orthodontic treatment did not always correspond to the individual norm of a patient. An increase in the transversal size of the upper dentition in the region of the premolars was determined in 44 patients (58.6%), a slight narrowing in the region of the first molars in 34 patients (45.4%), lengthening or shortening of the anterior part of the dental arch in 32 (42.7%) and 23 (30.6%) patients, respectively. With the proportionality of the mesio-distal dimensions of the incisors of the upper and lower jaws (Tonn's Index 1.34±0.03) and the relative macrodontia of the canines of the lower jaw (anterior Bolton's ratio 81.0±3.2%), the symmetrical position of the crowns of canines of the upper jaw and the value of the rotational angle of 28.0±2.1°corresponded to the functionally optimal results of orthodontic treatment.

Conclusion. Aesthetically satisfactory and functionally stable results of orthodontic treatment of patients with anomalies in the position of the crowns of the maxillary canines during the retention period correspond to the following biometric parameters of the upper dental arch and / or their combination: lengthening of the anterior region, an increase in the transversal size in the region of the first premolars and a decrease in the region of the first molars in maintaining the individual norm of intercanine width. The stability of the results of orthodontic treatment in patients with anomalies in the position of the canines and the shape and / or size of the dental arches is ensured by the maximum possible leveling of violations of the anatomical and topographic norms of the teeth position.