A Systematic Review Of Arch Width Changes In Extraction And Non-extraction Treatment

Objective：To evaluate the arch width changes in consecutively treatedextraction and non-extraction patients and to help practitioners makeprudent decisions when making treatment decisions.Methods: PubMed, Embase, Cochrane library,Web of Science,CENTRAL, SIGLE, VIP, CBM, CNKI and Wanfang Database weresearched from January first，1990to December30th，2012forrandomized or non-randomized controlled trials. What’s more, wehand searched NLM, Campbell library, WHOLIS, Evidence basedmedicine, and Journal of Orthodontics. Additionally, we used searchengine such as google to find out leaked studies. Literature filtering,data extraction and methodological quality evaluation were finishedindependently by two researchers and disagreements were solved bydiscussion. Original outcome data, if possible, were subjected tostatistical pooling by Review Manager5.2for meta-analysis.Results: Twelve studies met our inclusion criteria. Among them, twoare RCTs and ten are CBAs, including a total of846patients. This meta-analysis separately compared the maxillary inter-canine archwidth(12trials), the mandibular inter-canine width(12trials), the maxillaryinter-molar width(10trials), the mandibular inter-molar width(10trials).What’s more, one of the trails divided the patientsinto male group and female group respectively. So before data analysis weused statistical formula to merge the two sets of data together. Additionally,we do quality assessments of each study, found that all the RCTs studies areregarded as high-quality and all the CCTs studies are B grade (withmoderate risk of bias).①The change of maxillary inter-canine widthThe meta-analysis revealed that significant differences were foundin maxillary inter-canine width（WMD=0.55mm，95%CI[0.31，0.79]）,and only slight heterogeneity was detected (I2=21%, p=0.24).②The change of mandibular inter-canine widthThe meta-analysis revealed that significantly differences werefound in mandibular inter-canine width (WMD=0.62mm，95%CI[0.43,0.81]), and only slight heterogeneity was detected (I2=1%, p=0.43).③The change of maxillary inter-molar widthThe meta-analysis revealed that significantly differences werefound in maxillary inter-molar width(WMD=-2.24mm，95%CI[-2.72,-1.76]), and significant heterogeneity was detected (I2=58%, p=0.01). ④The change of mandibular inter-molar widthThe meta-analysis revealed that significantly differences werefound in mandibular inter-molar width (WMD=-1.91mm，95%CI[-2.13,-1.68]), and no heterogeneity was detected (I2=0%, p=0.69).Conclusions:①Since limited published high quality studies were included. Wesuggest that extraction treatment would not lead to narrowing of themaxillary inter-canine width compared with non-extraction treatment.②Moreover, we suggest that extraction treatment, as compared withnon-extraction treatment, may reduce significant increase of themandibular inter-canine width.③Still, extraction treatment would lead to narrowing of bothmaxillary and mandibular inter-molar width when compared withnon-extraction treatment.