title: The safety zone for mini-implant maxillary anchorage in Mongoloids.
abstract: OBJECTIVE
  This study aimed to establish a safety zone for the placement of mini-implants in the buccal surface between the second maxillary premolar (PM2) and first maxillary molar (M1) of Mongoloids.
  
  
  METHODS
  Thirty-two digital orthopantomograms of Mongoloids were selected and the interdental distance between the second premolar and first molar at 2, 5, 8 and 11 mm from the cemento-enamel junction (CEJ) was measured. The distance between the PM2 and M1 root apices and from the apices to the maxillary sinus was also determined.
  
  
  RESULTS
  The average width (mm) at 2 mm was 2.58 +/- 0.53; 5 mm was 3.47 +/- 0.61; 8 mm was 4.00 +/- 0.74, 11 mm was 4.36 +/- 0.71 and the distance between the apices was 7.49 +/- 0.79. Only half of the samples were measured at 11 mm, as many of the root apices were superimposed over the maxillary sinus. The measurement (mm) from PM2 root apex to the sinus was -0.18 +/- 1.56, from the mesiobuccal root apex of M1 (MB1) to the sinus was -1.94 +/- 1.70 and from the midpoint between their apices to the sinus was -2.96 +/- 2.06 (superimposed on the sinus).
  
  
  CONCLUSIONS
  The safest area to place mini-implants between the second premolar and the first molar in the maxilla of Mongoloids is between 5 to 8 mm above the CEJ.
authors.affiliation: Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia. weymc@um.edu.my
authors.forename: Mang Chek
authors.initials: MC
authors.lastname: Wey
authors.forename: Chung Nam
authors.initials: CN
authors.lastname: Shim
authors.forename: Meng Yit
authors.initials: MY
authors.lastname: Lee
authors.forename: Marhazlinda
authors.initials: M
authors.lastname: Jamaluddin
authors.forename: Wei Cheong
authors.initials: WC
authors.lastname: Ngeow
mesh_terms: D000539:Alveolar Process / Q000033:anatomy & histology / Q000601:surgery; D044466:Asian People; D001641:Bicuspid; D003724:Dental Arch / Q000033:anatomy & histology*; D015921:Dental Implants; D006801:Humans; D008437:Maxilla; D008963:Molar; D009811:Odontometry; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D011862:Radiography, Panoramic; D019227:Tooth Apex / Q000033:anatomy & histology
chemical_list: D015921:Dental Implants