Study of cervico-oral synergies in patients undergoing orthodontic treatment
Authors: Milutka Yu. A. , Basieva E. V. , Tarasov N. A. , Silin A. V. , Mokhov D. E. 
Published: June 2022

Introduction. The use of orthodontic treatment is becoming more and more common in the modern world. At the same time, it becomes acute to develop methods for identifying patients with an increased risk of undesirable side effects of treatment (pain, dysfunction of the temporomandibular joint, root resorption, etc.). The aim of the study is to investigate cervical-oral synergies in patients undergoing orthodontic treatment and compare it with their osteopathic status.

Materials and methods. 154 patients examined by an orthodontist were selected for the study and divided into 2 groups: Norm and Dyskinesia — according to the difference in the mouth opening width (the opening width in the extensional position minus the width in the neutral position of the head, E–N). The mouth opening width was measured by a caliper with thin lips. The Norm group included 86 people with a positive E–N difference, and the Dyskinesia group included 68 with a negative E–N difference. The patients age was the same in both groups (p>0,05). There were 31 % of men in the Norm group, and 16 % in the Dyskinesia group. In both groups, the angle of neck extension with open and closed mouth was measured, and the osteopathic status was assessed. At the same time, the osteopathic physician did not know which group the patients belonged to.

Results. The groups differed signiﬁ cantly by the difference of the width mouth opening (p<0,000001), and it indicates the correctness of the choice of this sign for the groups separation. The absolute value of the mouth opening width in the neutral position did not differ statistically signiﬁ cantly between the groups, and it was slightly below the norm of 49–50 mm (42 mm in the Norm group and 39 mm in the Dyskinesia group). The difference in the extension of the cervical spine with an open and closed mouth was also calculated (the angle of extension with an open mouth minus the angle of extension with a closed mouth). A statistically signiﬁ cant difference between the groups was obtained (p<0,0001). Absolute values of neck extension did not differ statistically signiﬁ cantly in the two groups. During the osteopathic examination, there was found a statistically signiﬁ cant (p<0,05) difference of the detection frequency of the following somatic dysfunctions (SD): SD of the neck region, the somatic component, in the Norm group in 34,1 % and in the Dyskinesia group in 57,4 %; as well as global SD: in the Norm group there were diagnosed only in 3,5 %, and in the Dyskinesia group — in 14,7 %.

Conclusion. Thus, patients with a negative E–H difference (the Dyskinesia group) differ statistically signiﬁ cantly from patients with a positive E–H difference in the difference of the movements′ volume in the neck, and by the set of somatic dysfunctions. The osteopathic status of these patients may cause a disorder of cervical-oral synergies. The measuring the width of the mouth opening in different positions of the head and calculating the difference in E–H could be used as an indicator that the patient needs correction of somatic dysfunctions during orthodontic treatment. It is planned to further study these synergies in relation to the practice of a dentist.