title: Cone beam computed tomographic measurement of maxillary central incisors to determine prevalence of facial alveolar bone width ≥2 mm.
abstract: BACKGROUND
  The initial thickness of maxillary bone has significant impact on the responding level of facial bone and soft tissue after extraction and immediate implant placement. A prevailing notion is that following implant placement in fresh extraction sites, at least 2 mm of facial bone is needed to prevent soft tissue recession, fenestration, and dehiscence.
  
  
  OBJECTIVE
  The purpose of this study was to use cone beam computed tomography (CBCT) to measure horizontal width of facial alveolar bone overlying healthy maxillary central incisors and to determine prevalence of bone thickness ≥2 mm.
  
  
  METHODS
  Tomographic data from 101 randomly selected patients were evaluated by two independent observers. Assessments were made of facial bone width at levels 1.0 to 10.0 mm apical to the bone crest.
  
  
  RESULTS
  Healthy maxillary central incisors (n= 202) were measured from 101 patient scans. The percent of teeth with facial bone ≥2 mm at levels 1, 2, 3, 4, and 5 mm from the bone crest was 0, 1.5, 2.0, 3.0, and 2.5%, respectively. Overall mean thickness of the bone was 1.05 mm for right and left central incisors combined. The range of individual measurements for all levels was 0 to 5.1 mm. The occurrence of ≥ 2 mm thickness bone measurements increased with increasing depth. However, mean widths observed at levels 6 to 10 mm from the crest ranged only 1.0 to 1.3 mm because of apparent fenestration occurrence (0 mm bone) in approximately 12% of teeth. Overall, no significant differences in bone thickness were found between ethnic, gender, age, or scan groups.
  
  
  CONCLUSIONS
  Using CBCT, occurrences of ≥2 mm maxillary facial alveolar bone were found on no more than 3% of root surfaces 1.0 to 5.0 mm apical to the bone crest in this sample of maxillary central incisors. The study evidenced prevalence of a thin facial alveolar bone (<2 mm) that may contribute to risk of facial bone fenestration, dehiscence, and soft tissue recession after immediate implant therapy.
authors.affiliation: University of Southern California School of Dentistry, Los Angeles, CA 90089-0641, USA. nowzari@usc.edu
authors.forename: Hessam
authors.initials: H
authors.lastname: Nowzari
authors.forename: Shervin
authors.initials: S
authors.lastname: Molayem
authors.forename: Ching Hsiu Ketty
authors.initials: CH
authors.lastname: Chiu
authors.forename: Sandra K
authors.initials: SK
authors.lastname: Rich
mesh_terms: D000293:Adolescent; D000328:Adult; D001741:Black or African American; D000368:Aged; D000369:Aged, 80 and over; D000539:Alveolar Process / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D001213:Asian; D002508:Cephalometry / Q000379:methods*; D054893:Cone-Beam Computed Tomography / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006630:Hispanic or Latino; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D007180:Incisor / Q000000981:diagnostic imaging*; D008297:Male; D008437:Maxilla / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D008875:Middle Aged; D012737:Sex Factors; D019237:Tooth Cervix / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D014092:Tooth Root / Q000000981:diagnostic imaging; D020390:Tooth Socket / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D044465:White People; D055815:Young Adult