Effect of molar distalization with clear aligners on occlusal vertical dimension in different vertical craniofacial patterns / 中国组织工程研究

ABSTRACT

BACKGROUND:Previous studies have shown that clear aligners can achieve molar distalization effectively,but it is not yet clear how the vertical dimensions change in patients with different vertical craniofacial patterns after molar distalization. OBJECTIVE:To evaluate the effect of molar distalization with clear aligners on occlusal vertical dimension in different vertical craniofacial patterns. METHODS:Forty patients(13 cases of Class Ⅰ malocclusion,20 cases of Class Ⅱ malocclusion,and 7 cases of Class Ⅲ malocclusion)were selected,including 13 cases in the high angle group,17 cases in the average angle group,and 10 cases in the low angle group.Among them,the age ranged from 10 to 53 years,with an average of 28.5 years.All patients were subjected to clear aligners for molar distalization.Lateral cephalometric films were taken before and after treatment.Cephalometric measurements,including the sagittal and vertical indicators of teeth and jaws,were measured by the same orthodontist,and each indicator was measured 3 times and averaged. RESULTS AND CONCLUSION:After orthodontic treatment,the crowded dentition was corrected,the overbite and overjet were back to normal and the lateral profile was improved significantly in all 40 patients.The GoGn-SN in the high angle group decreased by 0.4°,while the GoGn-SN in the average and low angle groups increased by less than 1°,the ANS-Me in the three groups increased by less than 1 mm.There was no statistically significant difference before and after treatment.There was a statistically significant decrease in the U6-PP in the low angle group by 0.47 mm(P<0.01).The L1-MP and the U1-SN in the average angle group significantly decreased by 0.83 mm(P<0.05)and by 6.46°(P<0.001),respectively.In conclusion,molar distalization with clear aligner treatment can control the vertical dimension effectively,prevent clockwise mandibular rotation,and maintain the lower face height.Patients with high angle can also undergo invisible orthodontics to distal molars.The realization rate of the anterior tooth intrusion movement by using clear aligners is insufficient,and the intrusion design should be increased to prevent the elongation phenomenon in anterior teeth.