title: Alveolar bone loss around incisors in Class I bidentoalveolar protrusion patients: a retrospective three-dimensional cone beam CT study.
abstract: OBJECTIVE
  The aim of this study was to test the null hypothesis that there is no difference in the alveolar bone thickness, bone loss or incidence of fenestrations between upper and lower incisors in skeletal Class I bidentoalveolar protrusive patients before orthodontic treatment.
  
  
  METHODS
  Three-dimensional (3D) cone beam CT (CBCT) images were taken of 24 patients from the Republic of Korea (17 females and 7 males). Reformatted CBCT images were used to measure labial and lingual alveolar bone thickness (ABT) of the 4 upper incisors and 4 lower incisors of the 24 patients (total n = 192 incisors) at every 1/10 of root length (Level 0, cementoenamel junction (CEJ) area; Level 10, root apex area) as well as alveolar bone area (ABA) and alveolar bone loss (%BL) rate to dental root length. The numbers of fenestration teeth were also tallied.
  
  
  RESULTS
  All anterior teeth were supported by <1 mm of ABT on the labial surfaces up to root length Level 8. ABA was statistically greater on the lingual aspect than the labial aspect in lower incisors. The %BL was 26.98% in the lower labial region, 19.27% in upper labial aspect and most severe on the lower lingual plate 31.25% compared with the labial plate. There were no significant differences in %BL between subgroups when categorized by sex or age. Fenestrations were 1.37 times more frequent on lower incisors (37) than upper incisors (27).
  
  
  CONCLUSIONS
  The null hypothesis was rejected, confirming that incisor periodontal support is poor and alveolar bone loss is severe even prior to the start of orthodontic treatment. Careful diagnosis using 3D CBCT images is needed to avoid iatrogenic degeneration of periodontal support around anterior teeth, particularly in the lower lingual bone plate region.
authors.affiliation: Graduate School of Clinical dental Science, The Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: K-Y
authors.initials: KY
authors.lastname: Nahm
authors.forename: J-H
authors.initials: JH
authors.lastname: Kang
authors.forename: S-C
authors.initials: SC
authors.lastname: Moon
authors.forename: Y-S
authors.initials: YS
authors.lastname: Choi
authors.forename: Y-A
authors.initials: YA
authors.lastname: Kook
authors.forename: S-H
authors.initials: SH
authors.lastname: Kim
authors.forename: Jc
authors.initials: J
authors.lastname: Huang
mesh_terms: D000293:Adolescent; D000328:Adult; D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging*; D015519:Bone Density; D002508:Cephalometry; D016009:Chi-Square Distribution; D002648:Child; D054893:Cone-Beam Computed Tomography; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D007180:Incisor / Q000002:abnormalities / Q000000981:diagnostic imaging*; D008297:Male; D008311:Malocclusion, Angle Class I / Q000000981:diagnostic imaging* / Q000628:therapy*; D009971:Orthodontics, Corrective; D012189:Retrospective Studies