| Objective: In this study,the PAR index,the irregularity index and X-ray cephalometric analysis were used to evaluate the changes of soft and hard tissues before and after treatment through reviewing the finished cases of mild to moderate anterior crowding treatment by clear aligner and conventional fixed appliance respectively to provide reference for Orthodontic treatment.Materials and methods: 60 cases treated by five chief physician in Dalian Stomatology Hospital Orthodontic were selected strictly according to the inclusion criteria,these 60 cases were mild to moderate crowding in anterior treated by clear aligner and fixed appliance.The plaster models of 60 patients were scored by PAR index and irregularity index analyzing level of malocclusion improvement.Cephalometric analysis of soft and hard tissues was used to evaluate these 60 patients before and after treatment.SPSS25.0statistical software was used to analyze the results.P-value < 0.05 was considered statistically significant.Result: 1.The treatment course of clear aligner group was(514.3 ±97.1)days.The treatment course of fixed appliance group was(596.1 ± 85.1)days,the difference between the two groups was statistically significant(P < 0.05).Clear aligner is more efficient than fixed appliance.2.There was no significant difference in PAR scores(midline,anterior segment alignment,buccal occlusion,overjet,overbite,PAR scores,weighted PAR scores)between the two groups before treatment(P > 0.05).After treatment,there were significant differences in the buccal occlusion relationship and PAR score between the clear aligner group and the fixed appliance group(P<0.01).3.Improvement in the score of each measure in the PAR index in the clear aligner and fixed appliance group,the difference was statistically significant(P < 0.05),In clear aligner group,weighted PAR score decreased by 87.8%,malocclusion "improved" in 30 cases,accounting for 100% of the total number of cases,in which "great improvement" occurred in 8 cases,accounting for 26.7% of the total number of cases.In the fixed appliance group,weighted PAR score decreased by 90.1%,30 cases of malocclusion "improved",accounting for 100% of the total number of cases,in which 16 cases had "great improvement",accounting for 53.3% of the total cases.Fixed appliance is better than clear aligner in changing malocclusion to a greater improvement.4.There was no significant difference between the clear aligner group and the fixed appliance group in the classification and numerical value of the difference between the maxillary and mandibular irregularity index.There was no significant difference in the maxillary irregularity index between the clear aligner group and the fixed appliance group(P >0.05),but there was a significant difference in the mandibular irregularity index(P < 0.05).Fixed appliance group better than clear aligner group.5.Only U1-L1(°)and LL-E line between the clear aligner group and the fixed appliance group were statistically significant after treatment(P <0.05).The difference of U1-NA,L1-NB(°)before and after treatment in the fixed appliance group was statistically significant(P <0.05).the labial inclination of upper and lower incisors was increased of the fixed appliance group,while the clear aligner group had no this phenomenon.Conclusions: Both clear aligner and traditional fixed appliance can improve malocclusion,and fixed appliance can improve malocclusion more effectively.As for the alignment of anterior teeth,the alignment effect of clear aligner in the upper anterior area is equivalent to that of fixed appliance,However,the fixed appliance is better than the clear aligner in the lower anterior area.Treatment of mild to moderate crowding of anterior teeth with fixed appliance,the labial inclination of upper and lower incisors was increased,but the clear aligner is not obvious.Clear aligner is more efficient than fixed appliance in the treatment of mild to moderate crowding cases in anterior. |
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