| Summary: | 碩士 === 高雄醫學大學 === 牙醫學研究所 === 96 === Background:
In the past several decades researches have been done to investigate the relationship between periodontitis and many microorganisms. Among the many types of periodontitis, the association between localized aggressive periodontitis and Aggregatibacter (Actinobacillus) actinomycetemcomitans had been intensely discussed, as this pathogenic bacteria has many virulent factors. It is commonly recognized that the distributions of A.actinomycetemcomitans serotypes and genotypes are associated with periodontal conditions. The periodontal pathogenic bacteria has been classified into six serotypes: a, b, c, d, e, f. Association between A. actinomycetemcomitans serotypes and periodontal conditions among Taiwanese and the distribution of the serotypes are still unclear. In this study, we used indirect immuno-fluorescence assay and polymerase chain reaction (PCR) to detect dental plaque of periodontal patients and healthy volunteers. The data obtained was used for further analysis of serotype distribution, prevalence, proportion and associations with periodontal status.
Methods:
Forty-five periodontal patients (all diagnosed chronic periodontitis) from Chung-Ho Memorial Hospital of Kaohsiung Medical University were included in our study. After x-ray and periodontal examinations, each patient’s periodontal type was assigned according to American Academy of Periodontology (1999). The control group consisted of 45 healthy volunteers from Kaohsiung Medical University. The inclusion criteria included: periodontal pockets size of less than or equal to 3 mm and no bleeding on probing. Dental plaques were obtained from the volunteers. The carrier rate, prevalence rate, and serotype distribution of A. actinomycetemcomitans were obtained by using indirect immuno-fluorescenc assay and polymerase chain reaction (PCR). Data collected was analyzed by Excel and JMP, Chi-square test, two-sample t-test and ANOVA were also performed.
Result:
1. Among 45 chronic periodontitis patients, the prevalence rate of A. actinomycetemcomitans was 33.33% (15/45). The occurrence of each serotype was: a (13.33%, 2/15), b (6.67%, 1/15), c (33.33%, 5/15), d (6.67%, 1/15), e (13.33%, 2/15), and untypeable (26.67%, 4/15). As for the 45 healthy volunteers, the prevalence rate was 2.22% (1/45),
2. In periodontal sites, the prevalence rate of A. actinomycetemcomitans was 23.33% (21/90). The occurrence of each serotype was: a (14.29%), b (4.76%). c (23.81%), d (4.76%), e (14.29%), and untypeable (38.1%)—the most common type. In gingivitis sites, the prevalence rate was 3.03% (1/33), with only one sample being serotype e. In healthy sites, the prevalence rate was 2.22% (1/45), in which only one sample occurred to untypeable.
3. In the supragingival plaque of periodontitis sites, the occurrence rate of each serotype was: a (0.04%±0.29), b (0.03%±0.21), c (0.06%±0.22), d (0.03%±0.22), e (0.02%±0.13). In the subgingival plaque of periodontitis sites, the occurrence rate of each serotype was: a (0.06%±0.31), b (0%), c (0.12%±0.38), d (0%), e (0.06%±0.30).
4. Among all the 90 patients and volunteers, mono-serotype infection accounted for 75% and poly-serotype infection for 25%.
5. It was concluded that the infection of A. actinomycetemcomitans has no association with sex, age, and other clinical parameters.
Conclusions:
This study was performed using indirect immuno-fluorescence assay and PCR to detect A. actinomycetemcomitan among periodontal patients and healthy volunteers in order to investigate its prevalence rate, serotype distribution and infection conditions. The results have shown that the occurrence rate of A. actinomycetemcomitan was higher in periodontal patients than healthy volunteers. Further investigations would be done on A. actinomycetemcomitan among Taiwanese people to gain more understanding of this pathogen, and in the hope of improving clinical treatment.
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