Analysis Of Dental And Basal Arch Widths In Late-Growth Youths With Different Sagittal Skeletal Patterns

Objective: Explore the correlation between the dental arches and basal arches with same sagittal facial pattern and the difference of those widths with different patterns by analyzing and measuring the width of different dental arches and basal arches in the late-growth youths.This evaluation will be the reference for the diagnosis,treatment and clinical treatment of malocclusion.Methods: The patients who attended Stomatology Hospital of Shenyang from September 2018 to February 2021 were divided into skeletal malocclusion Ⅰ,Ⅱ,and Ⅲ according to the sagittal facial type.50 cases were selected as the experimental group,and 46 cases with individual normal jaws were selected as the control group.The people in the control group came from 550 college student volunteers from Shenyang Pharmaceutical University.When taking CBCT,ask the patient to be in the natural head position(at this time the eye and ear plane should be parallel to the ground plane,and the midline of the human body should be aligned with the vertical rod of the machine),cusp interlaced position in the mouth,and N-shaped tongue position(the tongue is placed on top of the palate and directly behind the front teeth.Do not press the front teeth and close the lips)and do not swallow or speak.Measure and analyze the CBCT and plaster occlusal model taken at the first visit of the patient,including 8 dental indicators and 6 skeletal indicators,and perform male and female t-test analysis to compare gender differences in related measurement items in each group,to clarify the correlation between basal arch and dental arch of the same sagittal skeletal type,the difference of width between different sagittal skeletal types,and the change of inclination Angle of the first molars of upper and lower mandibular with different sagittal skeletal types.After importing the data into Microsoft Excel software for sorting then inputting it into SPSS20.0 statistical software.The mean value and standard deviation of 14 measurement data in each group were calculated.Pair independent sample t-test and Pearson correlation analysis were performed on the measurement items of the experimental group and the control group to compare the difference and correlation between the width of dental arch and basal arch.Results:1.All the sample measurement data show that the average value of women is smaller than that of men.Except for the width of the mandibular arch,the width of the basal arch in the maxillary canine area and the maxillary premolar area,there are significant differences in the measured values of the other groups.2.The width of dental arch is positively correlated with the width of basal arch,and the correlation gradually increases as the dental arch moves from the front to the back.3.Compared with skeletal class Ⅰ and skeletal class Ⅲ patients,the width of the middle and posterior segments of the maxillary dental arch is significantly reduced.4.Ⅰn class Ⅲ patients,the middle posterior segment of the mandibular arch is wider than that of normal occlusion,and the difference is statistically significant.Compared with patients with skeletal class Ⅰ and class Ⅱ,the middle and posterior basal arch of the skeletal class Ⅲ’s mandible is wider,And the difference is very significant.5.Ⅰn class Ⅲ patients,the first mandibular molar has a compensatory orthosis or tongue tilt compared with normal occlusion,and the difference is statistically significant.Conclusion:1.Male dental arches and basal arches are wider than females.2.There was a high correlation between the width of dental arch and basal arch in each segment,and the correlation gradually increased from front to back.3.Ⅰn patients with class Ⅱ,the width of the posterior segment of the maxillary dental arch was significantly reduced.This may be related to the narrower skull base complex in patients with skeletal class Ⅱ malocclusion,which affects the length of the maxillary dental arch and base arch.A compensatory increase is produced to compensate for the lack of development in the width.4.Compared with skeletal class Ⅰ and Ⅱ patients,patients with skeletal class Ⅲ have a wider mandibular base bone.Therefore,in clinical practice,it is suggested that more attention should be paid to the diagnosis and treatment of lateral dysregulation in the early treatment of patients with class Ⅲ,so as to achieve stable clinical treatment effect.5.The inclination angle of the upper and lower first molars is affected by many factors.Among them,the width of the dental arch is one of the important factors affecting its size.The width of the posterior segment of the skeletal class Ⅲ patients is larger,which is to establish the occlusal relationship of the cusp lock knot.Ⅰn order to establish the normal occlusal function,the mandibular first molars have a corresponding compensatory erection or tongue tilt.