Distribution of Porphyromonas gingivalis fimA genotypes in chronic apical periodontitis associated with symptoms.
BACKGROUND
Porphyromonas gingivalis (P. gingivalis) is an anaerobic bacterium involved in root canal infections whose fimbriae are classified into six genotypes (types I-V and Ib) based on nucleotide sequence. Accumulated evidence suggests there is significant association between P. gingivalis and some clinical symptoms of periodontal diseases. The present study aims to determine the prevalence of P. gingivalis fimA genotypes in apical periodontitis and to investigate the correlation between P. gingivalis fimA genotypes and clinical symptoms.


METHODS
Samples were obtained from 158 infected root canals with apical periodontitis. DNA was extracted and analyzed with a polymerase chain reaction-based identification assay. Odds ratios, 95% confidence intervals, and contingency coefficient were calculated for associating the fimA-specific genes with clinical symptoms.


RESULTS
P. gingivalis was detected in 39.9% of the inflected root canal samples and was found in 44.5% of P. gingivalis-positive specimens with symptoms. Types II (69.4%) were the most frequent in the symptomatic cases followed by type IV (32.7%). The occurrence of type I (64.3%) was significantly higher than any other genotypes in the asymptomatic apical periodontitis, whereas type II and type Ib were not identified. Statistical analysis revealed that the occurrences of types II, IV, and Ib fimA were associated with greater risk of clinical signs (swelling, sinus tract, or intracanal exudates) than type I.


CONCLUSIONS
Results from this study reinforce the association between P. gingivalis-specific fimA genotypic clones and apical periodontitis, indicating that fimA genotypes (types II, IV, and Ib) were related to the etiology of symptomatic periradicular diseases.
Wang
Qian
Q
State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, China.
Zhou
Xue-dong
XD
Zheng
Qing-hua
QH
Wang
Yao
Y
Tang
Lu
L
Huang
Ding-ming
DM
D000293:Adolescent; D000328:Adult; D000368:Aged; D058070:Asymptomatic Diseases; D016866:Bacteroidaceae Infections / Q000382:microbiology*; D002908:Chronic Disease; D003751:Dental Fistula / Q000382:microbiology; D003790:Dental Pulp Necrosis / Q000382:microbiology; D004487:Edema / Q000382:microbiology; D005122:Exudates and Transudates / Q000382:microbiology; D005260:Female; D036781:Fimbriae Proteins / Q000145:classification / Q000235:genetics*; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D010482:Periapical Abscess / Q000382:microbiology; D010485:Periapical Periodontitis / Q000382:microbiology*; D018933:Pili, Sex / Q000145:classification / Q000235:genetics*; D016133:Polymerase Chain Reaction; D016966:Porphyromonas gingivalis / Q000235:genetics* / Q000302:isolation & purification; D012390:Root Canal Therapy; D055815:Young Adult
C063055:fimbrillin; D036781:Fimbriae Proteins