title: Apical root resorption of incisors after orthodontic treatment of impacted maxillary canines: a radiographic study.
abstract: BACKGROUND
  The purpose of the study was to evaluate impacted maxillary canines as risk factor for orthodontic apical root resorption.
  
  
  METHODS
  The sample comprised 66 patients treated with fixed appliances. Thirty-two patients with a unilateral impacted maxillary canine, which was distanced from the roots of the incisors at a preliminary phase of treatment before bonding, formed the impaction group, and 34 patients without impactions served as the controls. Root shortening was calculated by using pretreatment and posttreatment intraoral radiographs. Inclination of the eruption path of the impacted canine relative to the midline, axis of the lateral incisor, and nasal line, root development, and the medial and vertical positions of the impacted tooth were recorded on orthopantomograms and lateral cephalometric films. The follicle/tooth ratio was evaluated by using periapical radiographs.
  
  
  RESULTS
  No significant difference in apical resorption of the maxillary incisors was detected between the impaction and control groups, or between the incisors of the impacted and contralateral sides in the same subject. Likewise, no difference in the severity of root resorption was found between the incisors of impacted side alone and the incisors of the control group. Mesial and vertical inclinations of the impacted canines were negatively related to a lateral incisor's root resorption. No correlations were found between resorption and medial or vertical position of the crown of the canine. The follicle/tooth ratio was significantly related to the mesial inclination of the impacted canine, but not to root resorption.
  
  
  CONCLUSIONS
  An impacted maxillary canine, after being distanced from the incisor roots, does not seem to be a risk factor for apical root resorption during orthodontic treatment.
authors.affiliation: Department of Clinical Dentistry, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway.
authors.forename: Elin Marie Gravdal
authors.initials: EM
authors.lastname: Brusveen
authors.forename: Pongsri
authors.initials: P
authors.lastname: Brudvik
authors.forename: Olav Egil
authors.initials: OE
authors.lastname: Bøe
authors.forename: Maria
authors.initials: M
authors.lastname: Mavragani
mesh_terms: D000293:Adolescent; D000328:Adult; D002508:Cephalometry; D002648:Child; D003481:Cuspid / Q000000981:diagnostic imaging / Q000473:pathology*; D003795:Dental Sac / Q000000981:diagnostic imaging; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007180:Incisor / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D008437:Maxilla / Q000000981:diagnostic imaging*; D009805:Odontogenesis / Q000502:physiology; D050793:Orthodontic Extrusion / Q000379:methods*; D016300:Radiography, Bitewing; D019252:Radiography, Dental, Digital; D011862:Radiography, Panoramic; D012189:Retrospective Studies; D012307:Risk Factors; D012391:Root Resorption / Q000000981:diagnostic imaging / Q000209:etiology*; D019227:Tooth Apex / Q000000981:diagnostic imaging* / Q000503:physiopathology; D019228:Tooth Crown / Q000000981:diagnostic imaging / Q000473:pathology; D014092:Tooth Root / Q000000981:diagnostic imaging / Q000473:pathology; D014095:Tooth, Impacted / Q000145:classification / Q000000981:diagnostic imaging / Q000628:therapy*; D055815:Young Adult