| Objective The Bolton index discrepancy is a common problem in clinical orthodontics.The Bolton index discrepancy appeared before or after clinical treatment,which affects the stability and aesthetics of the patient’s dental occlusion and is more likely to affect the patient’s chewing function.The purpose of this study was to investigate the effects of several common treatment methods on the Bolton index discrepancy,and to quantify the Bolton index discrepancy,and provide a clinical reference for the Bolton index discrepancy before and after clinical orthodontic treatment.Methods 1 Search PubMed,The Cochrane library,Embase,Web of Science,CNKI,Wanfang and other databases about experimental study of Bolton index discrepancy before and after different treatments for patients with different types of malocclusion.Full-text reading,quality evaluation,data extraction,systematic evaluation and metaanalysis of selected literature.Revman 5.3 software was used for data analysis and forest map funnel plots.The effect indicators were mean and 95% confidence intervals for sensitivity analysis.2 From 2014 to 2018,120 cases of patients with malocclusion were selected from the orthodontics department of Bochuang Stomatological Hospital of North China University of Science and Technology.According to the group of 30 cases of Group I,II and III,80 patients were treated with extraction,according to the four premolar extraction modes,each group of 20 cases,the Bolton index was calculated before and after several treatments.The measured data were statistically analyzed.Results 1 28 articles were reported a total of 4496 patients with different malocclusions Bolton index changes before and after different orthodontic technique.Meta-analysis based on Angle classification and treatment methods: 1)Bolton index calculation of the Angle classification malocclusions before correction(2872 cases).Angle Class I is larger than the Angle Class II anterior teeth[MD=-0.02,95%CI(-0.40,0.36),P=0.90],Angle Class II was smaller than Angle Class III anterior ratio [MD=-0.42,95% CI(-0.85,0.02),P=0.06],and the difference was not statistically significant.Angle Class I is significantly smaller than the Angle Class III anterior ratio[MD=-0.40,95%CI(-0.76,-0.04),P=0.03].Angle Class I is larger than Angle Class II overall ratio [MD=0.11,95%CI(-0.23,0.45),P=0.52],which is smaller than Angle Class III overall ratio [MD=-0.32,95%CI(-0.72,0.07),P=0.10];Angle II was smaller than Angle Class III overall ratio [MD=-0.43,95%CI(-0.77,-0.09),P=0.01],the difference was Statistical significance.2)Bolton index overall ratio extracted with four premolars Calculations(1565 cases),Bolton overall ratio of four first premolar extraction was significantly(P<0.0001)greater than that of four second premolar extraction [MD=0.89,95%CI(0.69,1.10)],was significantly(P<0.0001)higher than that of maxillary second premolar and mandibular first premolar extraction [MD=0.99,95%CI(0.77,1.21)].The Bolton overall ratio of four first premolar extraction was higher(P=0.49)than that of maxillary first premolar and mandibular second premolar extraction [MD=-0.06,95%CI(-0.24,0.11)].The Bolton overall ratio of four second premolar extraction was smaller than that of maxillary first premolar and mandibular second premolar extraction [MD=-1.08,95%CI(-1.25,-0.92),P < 0.00001],and the difference was statistically significant.The Bolton overall ratio of four second premolar extraction was greater than that of maxillary second premolar and mandibular first premolar extraction,and the difference was not statistically significant.The Bolton overall ratio of maxillary first premolar and mandibular second premolar extraction was larger significantly(P < 0.00001)than that of maxillary second premolar and mandibular first premolar extraction[MD=1.07,95%CI(0.84,1.30)];The Bolton overall ratio discrepancy of four first premolar extraction was higher than that of four second premolar extraction [MD=0.46,95% CI(0.25,0.66),P<0.0001],was greater significantly(P=0.0009)than that of maxillary second premolar and mandibular first premolar extraction [MD=0.36,95% CI(0.15,0.58)].The Bolton overall ratio discrepancy of four first premolar extraction was greater than that of maxillary first premolar and mandibular second premolar extraction [MD=0.07,95% CI(-0.08,0.22),P=0.34],and the difference was not statistically significant.The Bolton overall ratio discrepancy of four second premolar extraction was significantly(P=0.0001)less than that of maxillary first premolar and mandibular second premolar extraction [MD=-0.38,95% CI(-0.57,-0.18)].The Bolton overall ratio discrepancy of four second premolar extraction was significantly(P=0.13)greater than that of maxillary second premolar and mandibular first premolar extraction [MD=-0.12,95% CI(-0.27,0.03)].The Bolton overall ratio discrepancy of maxillary first premolar and mandibular second premolar extraction was significantly(P=0.04)larger than that of maxillary second premolar and mandibular first premolar extraction [MD=0.28,95% CI(0.02,0.55)];3)extraction of premolars and incisors(59 cases).The Bolton overall ratio of maxillary first premolar and mandibular incisor extraction was significantly greater than maxillary first premolar and mandibular incisor and premolar extraction(MD=3.59,95% CI(2.30,4.88)].The Bolton overall ratio discrepancy of maxillary first premolar and mandibular incisor extraction was significantly(P<0.0001)greater than the maxillary first premolar and mandibular incisor and premolar extraction [MD=2.10,95% CI(1.59,2.60)].2 Bolton anterior ratio were I(78.64±0.79),II(78.88±0.65),III(78.16±0.78),The Bolton overall ratio was 91.07±0.47 for I,90.87±0.55 for II,and 91.35±0.66,the difference of anterior ratio was statistically significant between Angle I and III,the differences between III and I were statistically significant(P<0.05);The four premolar extraction patterns were compared in pairs(P<0.05);There is a linear regression equation between overjet and Bolton overall ratio,which has a certain correlation(r=-0.589).Conclusions 1 Meta-analysis combined with clinical studies showed Angle Class III was larger than Angle I on Bolton anteriord ratio,Angle Class III was larger than Angle II on Bolton overall ratio.2 Four premolar extraction modes will cause Bolton overall ratio to decrease,When Bolton index is large,maxillary second premolar and mandibular first premolar or four second premolar extraction is adopted.while when Bolton index is small,four first premolar or maxillary first premolar and mandibular second premolar extraction mode is adopted.When the Bolton index is normal,the Bolton index caused by four second premolar extraction is the least adjustable 3 For every 1 mm increase in OJ,the Bolton index decreases by 0.435%.Figure 38;Table 5;Reference 96... |
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