title: The influence of loss of bone mass on induced periodontal disease: a radiographic and densitometric study of female rats.
abstract: BACKGROUND
  Changes in mineral density in the mandibular and femoral bones (BMD) after estrogen deficiency caused by ovariectomy (OVX) and the influence of these changes on induced periodontal disease were evaluated in female rats.
  
  
  METHODS
  Forty-eight female Holtzman rats (90 days old) were randomly divided into five groups: 0: control (N = 9); 1: SHAM without induced periodontal disease (N = 11); 2: SHAM with induced disease (N = 10); 3: OVX without induced disease (N = 9); and 4: OVX with induced disease (N = 9). In groups 2 and 4, the first lower molars were tied with ligatures for 30 days 120 days after surgery. After 5 months the animals were sacrificed to measure global mineral density (BMD) and that of the sub-regions of the mandible and femur by dual energy x-ray absorptiometry (DXA). The extent of vertical bone loss was evaluated with digital radiography by measuring the distance from the bone crest to the cemento-enamel junction at the mesial of the first lower molar.
  
  
  RESULTS
  Results of the femur (Kruskal-Wallis test) showed a significant difference (P <0.001) between the groups SHAM and OVX in bone density values for all regions. Comparison between the groups in relation to the BMD of the mandible, both in the sub-regions and global revealed no differences (P >0.05). The vertical bone loss measured for the groups with induced disease was similar (P = 0.713).
  
  
  CONCLUSIONS
  Differences between the groups were found in the bone mineral density BMD of the femur but not of the mandible. OVX had no influence on induced periodontal disease.
authors.affiliation: Diagnosis and Surgery Department, Division of Periodontics, School of Dentistry, State University of São Paulo (UNESP), Araraquara, SP, Brazil.
authors.forename: Silvana Regina Perez
authors.initials: SR
authors.lastname: Orrico
authors.forename: Daniela
authors.initials: D
authors.lastname: Gonçalves
authors.forename: Solange Teresinha
authors.initials: ST
authors.lastname: Galeazzi
authors.forename: Gabriela
authors.initials: G
authors.lastname: Giro
authors.forename: Lilian
authors.initials: L
authors.lastname: Takayama
authors.forename: Rosa Maria Rodrigues
authors.initials: RM
authors.lastname: Pereira
mesh_terms: D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology*; D000818:Animals; D015519:Bone Density; D003720:Densitometry; D004967:Estrogens / Q000172:deficiency*; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000503:physiopathology; D008336:Mandibular Diseases / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology*; D010052:Ovariectomy; D011859:Radiography; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D004967:Estrogens