Clinical Efficacy Of Activator Appliance In The Treatment Of Skeletal Class Ⅱ Malocclusion:A Systematic Review And Meta-analysis

Objectives:To systematically evaluate the changes of teeth,hard tissues and profile of patients with skeletal class Ⅱ malocclusion and mandibular retraction after treatment with activator appliance,and compare them with patients without any treatment to explore the clinical efficacy of muscle activator.Methods:Retrievalling relevant database:PubMed,OVID,Cochrane Library,Sciencedirect,Wiley Online Library,Embase,Web of SCI,CBM,CNKI,CSTJ and WanFang Data.While NLM,Evidence based medicine,and the Journal of Orthodontics were searched manually,the search time is up to March 2019.Additionally,we used search engine such as Google to find out omissive studies.Two researchers independently completed literature screening,data extraction and methodological quality evaluation,and disagreements were solved by discussion.RevMan 5.3 software was used for meta-analysis of the included literature.Results:Finally,16 eligible articles were included,namely five RCTs and eleven CCTs.A total of 742 patients were enrolled in this study,RCTs have 153 patients,including 74 patients treated with activator appliance,and 79 untreated patients,CCTs have 589 patients,of whom 331 were treated with activator appliance,258 patients were untreated.Thirteen outcome indicators of teeth,bone tissue and soft tissue were compared and analyzed:SNA,SNB,ANB,SN-MP,ANS-Me,Co-Gn,Go-Me,overjet,overbite,U1-SN,L1-MP,UL-E,LL-E.Methodological quality evaluation was carried out for the included studies.Five RCTs evaluations were of medium quality and six CCTs evaluations were of B grade.Meta-analysis results were as follows:1.Changes of bone tissue:Compared with untreated group,SNA and ANB decreased and SNB,SN-MP,ANS-Me,Co-Gn and Go-Me increased after the treatment of activator appliance,with significant difference(P<0.001);2.Dental changes:Compared with the untreated group,the overjet,overbite and U1-SN in the treated group decreased significantly,while L1-MP increased significantly(P<0.0001);3.Soft tissue changes:Compared with untreated patients,UL-E of patients treated with activator appliance decreased significantly(P<0.0001);there was no significant difference in LL-E between the two groups(P=0.09).Conclusions:For the patients with skeletal class Ⅱ malocclusion,the activator appliance can inhibit the growth of maxilla to a certain extent,promote mandibular length and position forward,make mandible rotate a little backward and lower,increase the height of mandible,and significantly reduce the inclination of upper anterior teeth,overjet and overbite,and decrease the convexity of upper lip.For the changes of soft tissue,due to the limited quantity and quality of the literature,more high-quality and long-term randomized controlled trials are needed to provide better evidence.