Comparison Of Patients With Different Cervical Vertebral Maturation Stages Before And After Arch Expansion Treatment Based On Cone-Beam Computed Tomography

BACKGROUD:maxillary transverse deficiency(MTD)is a common malformation in clinical practice.It has been reported in the literature that the incidence of maxillary transverse deficiency is 8%-23% in adolescents and about 10% in adult orthodontic patients.For the treatment of maxillary transverse deficiency,a variety of palatal expansion devices are used clinically.The Hyrax appliance is still the most commonly used dental support palatal expansion device for children in the middle mixed dentition stage due to its simple appliance,comfortable wearing and good effect of arch expansion.The use of teeth as anchorage can easily cause buccal tilt of teeth and affect the therapeutic effect.Through the study of bone effect,dental effect and nasal width changes before and after arch expansion treatment in patients with different cervical vertebra ages,we can be guided to carry out related clinical operations better.OBJECTIVE: The changes of maxillary basal arch width,molar angle,palatal suture width and nasal cavity width were analyzed in patients with different cervical vertebral maturation stages before and after maxillary rapid arch expansion treatment,providing more reference for orthodontic design and treatment in the future.METHODS: A total of 45 patients with maxillary lateral,insufficient development that underwent arch expansion treatment in Jiaxing Second Hospital between February2021 and February 2022 were selected for the study.Patients were retrospectively grouped based on the cervical vertebral maturation stages,and divided into the pregrowth(15 cases),mid-growth(15 cases)and post-growth groups(15 cases).All patients had oral cone-beam computed tomography(CBCT)and lateral cranial radiographs taken before and after the treatment.Maxillary basal arch width,palatal suture width,nasal cavity width and molar angle were measured and analyzed using paired samples t-test,ANOVA and least significant difference test(LSD-T).RESULTS: The maxillary basal arch width,palatal suture width,nasal cavity width and molar angle in the three groups were significantly changed after arch expansion treatment(p<0.05).There was no statistically significant difference in all measurement indexes between patients in the pre-growth and the mid-growth groups(p>0.05),but there was statistically significant difference between patients in the pre-growth and the late-growth groups(p<0.05).There were statistically significant differences in all measurement indexes between the middle-growth and the late-growth group(p<0.05).CONCLUSIONS: Rapid expansion of arch can be used to enlarge the width of palatal suture,maxillary basal arch and nasal cavity in adolescent patients of different cervical vertebral maturation stages.With the increase of cervical vertebral maturation stages,the bony effect of expansion of arch gradually decreases,while the dental effect increases.Appropriate overcorrection should be made during arch expansion in late growth and excessive tooth tilt should be avoided to conceal bony width irregularities.