A comparative analysis of orthodontic devices used in the treatment of narrow maxilla in children with mixed dentition

Aim: to evaluate and compare the parameters of maxilla expansion in children with mixed dentition under the influence of various orthodontic appliances. Material and methods. 76 children with bilateral maxillary narrowing aged from 6 to 12 years old (М = 8.1 ± 1.2) were examined by anthropometric and radiographic methods. Comparative analysis of parameters characterizing maxillary expansion between the study groups was performed using the Student’s t-test and the Mann–Whitney U-test. Values were considered statistically significant at p 0.001. Results. The expansion of the upper dental arch occurred in patients of both groups. However, in patients of the main group, whose maxilla was expanded using a fixed expansion appliance with a Hyrex screw, the most significant differences on plaster models were found for all parameters (p 0.001), except for inter canine width between teeth 5.3-6.3 (p=0.059). In patients of the comparison group, after expansion of the maxilla using a removable appliance with a standard screw, the parameters of the maxilla width according to CBCT data increased in average on 1.17 mm. The difference between the transversal dimensions of the upper and lower jaws, which characterizes the degree of maxilla narrowing, decreased insignificantly from 5.78 (2.28; 6.92) mm to 5.05 (1.67; 2.93) mm. Conclusion. The true skeletal expansion in patients with maxillary narrowing and mixed dentition is achieved using fixed appliances with a Hyrex screw, while orthodontic treatment with removable appliances and standard screw has primarily a dentoalveolar expansion effect.