title: Anatomical landmarks of maxillary bifurcated first premolars and their influence on periodontal diagnosis and treatment.
abstract: OBJECTIVE
  To assess the anatomical landmarks of the roots of bifurcated maxillary first premolars and study their effect on the diagnosis and management of periodontal disease.
  
  
  METHODS
  One hundred sixty-five maxillary first premolars were selected. The frequency of single-, two-rooted, and three-rooted premolars was assessed, but only the dual-rooted were used for the purpose of this study. For each tooth, the following measurements were obtained using a micrometer caliper: buccal and palatal root length, mesial and distal root trunk length, crown length, and width of the furcation entrance. The types of root trunk were classified according to the ratio of root trunk height to root length into types A, B and C. Root trunk types A, B and C are defined as root trunks involving the cervical third or less, up to half of the length of the root, or greater than the apical half of the root, respectively. The presence of any root grooves and concavities, as well as bifurational ridges, was assessed. The crown to root ratio was calculated.
  
  
  RESULTS
  Of the 165 maxillary first premolar teeth retrieved, 100 (60.6%) were two-rooted, 62 (37.57%) were single-rooted, and three (1.81%) were triple-rooted. Type A root trunks comprised only 7% of the examined teeth, while types B and C had more or less comparable results (46% and 47% respectively). Type B was more common in distal root trunks while type C was dominant in mesial root trunks. Bifurcation ridges were observed in 37% of the teeth; the mean root trunk length was greater in teeth with bifurcation ridges than in teeth without (7.41 mm vs. 5.96 mm). Root grooves and concavities were found in 96% of the mesial aspects of the root, and in 57% of the palatal aspect of the buccal root. The mean width of the furcation entrance was 0.89 +/- 0.19 mm (range 0.39-1.28). The average crown to root ratio was 0.69:1.
  
  
  CONCLUSIONS
  Awareness of root surface anatomical variations may help the practitioner when assessing the diagnosis, treatment plan and prognosis of periodontally involved two-rooted maxillary premolars.
authors: King Hussein Medical Center, Dental Department, Amman, Jordan. rhdababneh@yahoo.com
authors: Reem
authors: R
authors: Dababneh
authors: Rania
authors: R
authors: Rodan
mesh_terms: D059925:Anatomic Landmarks; D001641:Bicuspid / Q000033:anatomy & histology*; D017823:Furcation Defects / Q000175:diagnosis*; D006801:Humans; D009811:Odontometry; D017622:Periodontal Attachment Loss / Q000175:diagnosis*; D011379:Prognosis; D012307:Risk Factors; D019228:Tooth Crown / Q000033:anatomy & histology; D014092:Tooth Root / Q000033:anatomy & histology*