| Purpose:The mandibular asymmetry of hemifacial microsomia can be effectively repaired by the treatment of mandibular ramus distraction osteogenesis,but there are different rate of recurrence.At present,it is believed that the effect of soft tissue around the mandible on new bone after distraction osteogenesis has important effect on recurrence.The functional orthodontic which is widely used in orthognathic surge can balance the force of muscle and soft tissue around the mandible on the bone.The combination of functional orthodontic and distraction osteogenesis improve the stability of postoperative effect theoretically,however,there is no case-control study.In this article,Three-dimensional ct measurements were performed to compare the mandibular occlusal plane of the mandibular ramus treated with the joint fixation of the jaw plate and the patient with the lower mandibular ramus alone when the extensor was removed,as well as the differences in mandibular length,occlusal plane maintenance and mandibular deviation during postoperative follow-up.The effect of this treatment method was evaluated and the theoretical basis was provided for the treatment of this kind of deformity.Methods:A total of 50 cases of children with complete data of HFM patients who were on the treatment from 2011 to 2017 were selected.The patients treated with the combination of functional orthodontic and distraction osteogenesis were selected as the experimental group,and the patients with single use of distraction osteogenesis were treated as the control group,and the two groups were respectively 25 patients.Measure the deflection of the jaw line when the extender is removed.A total of 5 patients with complete follow-up data were selected from 10 patients with extensor.We set up three time points of measurement,respectively for preoperative,taking out the extender and postoperative follow-up(9-24 months).The CT data of each stage were imported into ProPlan CMF 3.0 software for 3d modeling and the markers of various bone markers,and the reference plane was established.The recent effect was evaluated by the deviation Angle of jaw occlusion when the extender was removed.The total length of the mandible,the plane deviation of occlusion and the change of the mandible position were measured to evaluate the long term effect.Calculate the improvement amount and loss amount of each case in three measuring time and get the recurrence rate.The data were imported into SPSS software to analyze.Results:The 3d CT reconstruction of all cases had good stereoscopic effect.In the resent effect group,the sample size is still available,and the test conforms to the normal distribution,and the mean difference is analyzed by independent sample t test.The long-term follow-up group was two independent samples,but the sample size was small and did not conform to the normal distribution.Wilcoxon rank sum test were selected for analysis.The P value was set at 0.05,and the sig<0.05 was calculated to indicate that there was significant difference between the two groups,otherwise there was no significant difference between the two groups.In the recent evaluation,the occlusion Angle of the experimental group was 0.0227 + 0.0431(-0.1026-0.1018)rad,and the occlusion deviation of the control group was 0.0598 +0.0528(-0.04-0.2195)rad,sig=0.009>0.05.Therefore,there was a statistical difference between the two groups.In the evaluation of long-term effects,the total length of the mandible in the experimental group was 26.84%±9.75%,and the response rate of the control group was 25.3%± 10.09%,and the Sig was 0.917.The rate of occlusion of the experimental group was 39.27%± 10.09%,and the recovery rate of the control group was 38.04%±19.57%,and Sig was 0.465.The recovery rate of the mandible in the experimental group was 32.01%±23.09%,and the recovery rate of the control group was 39.17%±26.27%,and the Sig was 0.602.All group above was sig>0.05,so there was no statistical difference in the total length of the mandible,the Angle of occlusion and the deviation of the mandible,between the experimental group and the control group.Conclusion:In this study,a comparative study was conducted on the treatment of the mandibular plate and the patients with small facial microdeformity of the single side.The recent results were evaluated by measuring the occlusal skewness when the extender was taken out,and it was found that the occlusal deviation Angle of the experimental group was less than that of the control group,and there were significant differences in the two groups.The facial bone markers of the three time points were measured before,during and after the operation,and the total length of mandible,the degree of occlusion deviation and the degree of deviation of mandible were analyzed.No significant difference was found in statistics.The study showed that the combination of stretch and osteotomy was used for the treatment of maxillary plate,which could obtain a better occlusal plane in the early stage.In our treatment,however,as a result of a long period of time after a fixed period,tractor wear out with jaw plate does not improve the long-term stability of the postoperative patients,which still needs further large sample research. |
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