title: Evaluation and comparison of root resorption between tooth-borne and tooth-tissue borne rapid maxillary expansion appliances: A CBCT study.
abstract: OBJECTIVE
  To compare volumetric root resorption after rapid maxillary expansion (RME) between tooth-borne and tissue-borne appliances using CBCT. Repair in resorption cavities after 6 months of fixed retention was also compared.
  
  
  METHODS
  A sample of 33 subjects were randomly divided into two groups: Hyrax (n  = 16) and Haas (n = 17). CBCT scans were taken 6 months before expansion, immediately after expansion, and 6 months after fixed retention. Mimics Innovation V 16.0 software was used for segmentation and volumetric measurement of 198 teeth. Bland-Altman plots, independent samples t test, repeated measures analysis of variance, and the Friedman test were used for statistical analysis.
  
  
  RESULTS
  Differences in root resorption after RME and repair after retention were not significant between the hyrax and Haas appliances or between male and female. Significant differences were found between preexpansion and postexpansion root volumes in the first premolars and molars--even in unattached second premolars. When the percentage of root volume loss is considered, no significant difference was found between the first premolar, second premolar, and first molar. Volumetric changes after 6 months of retention were not statistically significant.
  
  
  CONCLUSIONS
  More resorption was observed in the Hyrax expander group. But it was not statistically significant. Repair was observed after 6 months of retention. Heavy RME forces affected premolars and molar similarly.
authors.affiliation: a  Research Assistant, Department of Orthodontics, School of Dentistry, Ege University, Izmir, Turkey.
authors.forename: Furkan
authors.initials: F
authors.lastname: Dindaroğlu
authors.affiliation: b  Professor, Department of Orthodontics, School of Dentistry, Ege University, Izmir, Turkey.
authors.forename: Servet
authors.initials: S
authors.lastname: Doğan
mesh_terms: D001641:Bicuspid; D005260:Female; D006801:Humans; D008297:Male; D008963:Molar; D009967:Orthodontic Appliances; D010155:Palatal Expansion Technique; D012391:Root Resorption
keywords: CBCT; Root resorption; Segmentation