title: Comparison of anterior and posterior mini-implant-assisted maxillary incisor intrusion: Root resorption and treatment efficiency.
abstract: OBJECTIVE
  To compare, through cone-beam computed tomography (CBCT), the root resorption and treatment efficiency of two different mini-implant-assisted modalities in intruding the maxillary incisors.
  
  
  METHODS
  Thirty-two adults who had deep bite and elongated maxillary incisors were randomly allocated to two groups: anterior mini-implant group (AMG) and posterior mini-implant group (PMG). In the AMG, approximately 40 g of force was applied per side with elastic chains from mini-implants placed between the lateral incisors and canines and in the PMG, with beta-titanium wires from mini-implants placed between the second premolars and first molars. This study was conducted on CBCT scans taken before intrusion and after 4 months of intrusion. Data were analyzed by means of a paired t-test, independent t-test, and Pearson's correlation test.
  
  
  RESULTS
  One patient was excluded from the AMG due to mini-implant loosening. While the incisors showed a significant reduction in length and volume, this amount was greater in the AMG, especially in the central incisors (P < .05). Together with the mean intrusion rates of 0.62 and 0.39 mm/mo in the AMG and PMG respectively, the center of resistance of the incisors showed distal movement with labial tipping; these changes were greater in the PMG (P < .001). Volumetric root resorption was correlated with the amount of intrusion (P < .05).
  
  
  CONCLUSIONS
  Intrusion anchoring from posterior mini-implants is preferred in cases of upright incisors, as the use of such mechanics directs the roots into the spongiosa where they undergo less root resorption and more labial tipping.
authors.affiliation: a  Assistant Professor, Department of Orthodontics, Faculty of Dentistry, Ege University, Izmir, Turkey.
authors.forename: Isil
authors.initials: I
authors.lastname: Aras
authors.affiliation: b  Professor, Department of Orthodontics, Faculty of Dentistry, Ege University, Izmir, Turkey.
authors.forename: Ali V
authors.initials: AV
authors.lastname: Tuncer
mesh_terms: D054893:Cone-Beam Computed Tomography; D006801:Humans; D007180:Incisor; D008437:Maxilla; D052280:Orthodontic Anchorage Procedures; D011897:Random Allocation; D012391:Root Resorption; D014087:Tooth Movement Techniques
keywords: Cone-beam computed tomography; Incisor intrusion; Mini-implant