title: Residual ridge dimensions at edentulous maxillary first molar sites and periodontal bone loss among two ethnic cohorts seeking tooth replacement.
abstract: OBJECTIVE
  To study residual ridge dimensions at edentulous first molar sites in relation to periodontal bone loss among cohorts of partially edentulous Asian Indian and Hong Kong Chinese subjects seeking tooth replacement.
  
  
  METHODS
  A total of 628 edentulous maxillary first molar sites were analyzed on Cone Beam Computed Tomography scans of 225 Asian Indian (I) and 232 Hong Kong Chinese (C) partially edentulous adults seeking tooth replacement. Age, ethnicity, gender, total tooth loss, the presence or absence of adjacent teeth, categories of periodontal status defined according to radiographic alveolar bone loss (P0: periodontal health, P1: incipient to moderate disease, P2: severe periodontal disease) and sinus membrane abnormalities were noted. Alveolar ridge height (RH), widths at 1 and 3 mm from crest (RW1; RW3), and relative position of the bone crest (RR) were measured.
  
  
  RESULTS
  Prevalence of P2 status was most frequent in both cohorts(C: 50.4% I: 49.2%). P2 had lowest ridge heights; 13.1% C P2 and 14%I P2 had RH < 2 mm. Sites with both RH <8 mm and RW1 < 6 mm occurred at 59%C P2 and 68%I P2. Sinus membrane abnormalities were most frequent in P2. Periodontal status and sinus membrane abnormality increased the odds of RH <5 mm and RH <8 mm more than 2-fold; additionally, gender and ethnicity significantly impacted RH <8 mm. Gender and adjacent tooth status significantly affected RW1.
  
  
  CONCLUSIONS
  Incident advanced periodontal disease was common among Asian Indian and Hong Kong Chinese subjects seeking tooth replacement and associated with lower available bone heights. Ethnicity, gender, sinus membrane thickening affected available bone height in the subsinus region, while the presence of adjacent teeth- and age-affected residual ridge width.
authors.affiliation: Department of Implant Dentistry, Oral Rehabilitation, Faculty of Dentistry, University of Hong Kong, Hong Kong, SAR Hong Kong, China; Department of Periodontology and Oral Implantology, Dr D. Y. Patil Dental College and Hospital, D Y Patil Vidyapeeth, Pune, India.
authors.forename: Aneesha
authors.initials: A
authors.lastname: Acharya
authors.forename: Jia
authors.initials: J
authors.lastname: Hao
authors.forename: Nikos
authors.initials: N
authors.lastname: Mattheos
authors.forename: Anson
authors.initials: A
authors.lastname: Chau
authors.forename: Prashant
authors.initials: P
authors.lastname: Shirke
authors.forename: Niklaus P
authors.initials: NP
authors.lastname: Lang
mesh_terms: D000328:Adult; D000368:Aged; D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging* / Q000208:ethnology; D000539:Alveolar Process / Q000000981:diagnostic imaging*; D002681:China / Q000208:ethnology; D015331:Cohort Studies; D054893:Cone-Beam Computed Tomography / Q000379:methods; D003430:Cross-Sectional Studies; D015921:Dental Implants; D005260:Female; D006723:Hong Kong; D006801:Humans; D007194:India / Q000208:ethnology; D007576:Jaw, Edentulous, Partially / Q000000981:diagnostic imaging* / Q000534:rehabilitation; D008297:Male; D008437:Maxilla / Q000000981:diagnostic imaging*; D008443:Maxillary Sinus / Q000000981:diagnostic imaging; D008875:Middle Aged; D008963:Molar; D009297:Nasal Mucosa / Q000000981:diagnostic imaging; D017622:Periodontal Attachment Loss / Q000000981:diagnostic imaging; D010512:Periodontal Index; D012737:Sex Factors; D016388:Tooth Loss / Q000534:rehabilitation
chemical_list: D015921:Dental Implants
keywords: CT imaging; clinical assessment; diagnosis; imaging; radiology