Effect of Periodontal Pathogens on Total Bone Volume Fraction:A Phenotypic Study

Summary:Studies have shown that periodontal pathogens can enter the bloodstream,causing a series of reactions that can lead to a variety of systemic diseases.Epidemiological investigations also found a tight correlation between periodontitis(PD)and osteoporosis.This study aimed to further explore the effect of periodontal pathogens on bone volume fraction like bone tissue and mass,and explain the relationship between PD and osteoporosis.Sprague Dawley rats(female,16 weeks old)were divided into the wild-type(WT)control group(m=9)and PD group(n=9).After eight weeks,periodontal tissues and ligatures,the fourth lumbar vertebra,the femur,the tibia,and blood were extracted and analyzed by micro-computed tomography(micro-CT),hematoxylin and eosin(H&E)staining,tartrate-resistant acid phosphatase(TRAP)staining,polymerase chain reaction(PCR),and enzyme-linked immunoassay(ELISA),respectively.We found that the bone mass of the lumbar vertebra,femur,and tibia was decreased in the PD group.The number of osteoclasts was higher in bone tissue in the PD group than in the WT group(P<0.05).The levels of inflammatory mediators and type I collagen C-terminal peptide(CTX-1)were higher in the PD group than in the WT group(P<0.05),although no significant difference in bone glutamic acid protein(BGP)levels was observed(P>0.05).In addition,we detected several periodontal pathogens,such as Porphyromonas gingivalis,Actinobacillus actinomycetemcomitans,and Fusobacterium nucleatum,in blood samples from rats in the PD group.These findings suggest that periodontal pathogens can enter the blood circulation from periodontal tissue,promote a systemic inflammation response,and subsequently reduce systemic bone density.

STUDY ON ADHERENCE ABILITY OF PERIODONTAL PATHOGENS AND CARIOGENIC BACTERIA TO HYDROXYAPATITE DISKS

Objective To study the adherence activity of six representative periodontopathic and cariogenic bacteria to hydroxyapatite disks. Methods Six periodontopathic and cariogenic bacteria of P. gingivalis, A. actinomycetemcomitans, F. nucleatum, S. sanguis, A. viscosus and S. mutans were cultured in modified MD-300 chemostat according to total fifteen experimental groups of single-specie and each pair of periodontal pathogens and cariogenic bacteria, respectively. After 1h attached live bacteria on removable hydroxyapatite disks was analyzed by culture technologies to evaluate the adherence level. Results The adherence activity of periodontopathic and cariogenic bacteria to HA was in the following order: S. sanguis > A. viscosus> S. mutans> A. actinomycetemcomitans > F. nucleatum > P. gingivalis. The number of periodontopathic bacteria to HA was enhanced by S. sanguis and A. viscosus,respectively.When mix-cultivated with S. mutans, the colonization of P. gingivalis was reduced significantly(P<0.001). Periodontopathic bacteria had no effect on the adherence activity of S. mutans and A. viscosus, except S. sanguis. Conclusion It was showed that the adherence activity of periodontal pathogens was weaker than that of cariogenic bacteria and emphasized the importance of bacterial adherence in determining the level of bacterial colonization on tooth surfaces. It was suggested that periodontopathic bacteria can utilize initial colonizers to become those predominant bacteria in periodontal ecosystem, which maybe have close relation to the periodontopathic mechanism.

Discrimination of periodontal pathogens using Raman spectroscopy combined with machine learning algorithms

Periodontitis is closely related to many systemic diseases linked by different periodontal pathogens.To unravel the relationship between periodontitis and systemic diseases,it is very important to correctly discriminate major periodontal pathogens.To realize convenient,effcient,and high-accuracy bacterial species classification,the authors use Raman spectroscopy combined with machine learning algorithms to distinguish three major periodontal pathogens Porphyromonas gingivalis(Pg),Fusobacterium nucleatum(Fn),and Aggregatibacter actinomycetemcomitans(Aa).The result shows that this novel method can successfully discriminate the three abovementioned periodontal pathogens.Moreover,the classification accuracies for the three categories of the original data were 94.7%at the sample level and 93.9%at the spectrum level by the machine learning algorithm extra trees.This study provides a fast,simple,and accurate method which is very beneficial to differentiate periodontal pathogens.

Detection of periodontal pathogens in the patients with aortic aneurysm

Background The occurrence and development of aortic aneurysm （AA） are associated with infection.Some researchers have detected the DNA of periodontal pathogens in AA samples in certain populations.However,it has not been done in Chinese population.The objective of this study was to evaluate the prevalence of periodontal pathogens in oral tissue samples and aneurysm samples of AA patients.Methods Eighty-nine subjects with AA and 59 subjects without AA were examined.Periodontal clinical parameters were evaluated.Unstimulated saliva and subgingival plaque somples were collected from all subjects.Twenty-six dissected AA samples were obtained.Evidence of eight periodontal pathogens including Porphyromonas gingivalis （Pg）,Actinobacillus actinomycetemcomitans （Aa）,Prevotella intermedia （Pi）,Tannerella forsythensis （Tf）,Treponema denticola （Td）,Campylobacter rectus （Cr）,Fusobacterium nucleatum （Fn）,and Prevotella nigrescens （Pn） was ascertained in all samples by 16S rRNA-based polymerase chain reaction （PCR） assay.Results The periodontal indexes including plaque index （PLI）,probing depth （PD）,bleeding index （BI）,and clinical attachment loss （CAL）,of the six Ramfjord index teeth were significantly higher in the AA group than those in the control group （P ＜0.01）.Eight periodontal pathogens in subgingival plaque samples were more frequently detected in the AA group than in control group.The difference in prevalence between the groups was significant for six （out of eight） periodontal pathogens assayed （Pg,Pi,Fn,Pn,Tf,and Td,P ＜0.01）.Additionally,all eight periodontal pathogens were more frequently detected in saliva samples of the AA group than in those of the control group,again with six （out of eight） （Pg,Pi,Fn,Cr,Tf,and Td） displaying significant differences in prevalence between the two groups （P ＜0.01）.Out of 26 aneurysm samples examined,Pg,Pi,Fn,Crand Tfwere detected in 6 （23.1％）,2 （7.7％）,3 （11.5％）,1 （3.8％）,2 （7.7％）,respectively,and Aa,Pn,and Td were not detected in dissected aneurysm samples.Conclusion Results of this study suggested that periodontal infection is associated with the occurrence of AA.

Effects of Ginkgo Biloba Extract on Periodontal Pathogens and Its Clinical Efficacy as Adjuvant Treatment

Objective：To determine the effects of Ginkgo biloba extract（EGB） on major periodontal pathogens in subgingival plaque.Methods：Sixty patients with moderate to severe periodontitis were selected and randomly assigned to 3 groups：EGB group,a positive（periocline） and a negative control groups.Subgingival plaque samples were collected before treatment and 1 week,2 months and 4 months after treatment.The detection rates of 4 major periodontal pathogens—Treponema denticola（Td）,Tannerella forsythus（Tf）,Prevotella intermedia（Pi）,and Porphyromonas gingivalis（Pg）—were detected by polymerase chain reaction（PCR）.Clinical indicators were examined before treatment,3 and 6 months after treatment.Results：EGB significantly decreased the detection rate of all the 4 pathogens 1 week after treatment,and then gradually increased at 2 and 4 months.EGB＇s inhibition effect was better than or comparable to periocline,except for Pg in short-term.The difference of plaque index（PLI） and bleeding index（Bl） was not statistically significant among the groups,while for probing depth（PD） and attachment loss（AL）,the difference was statistically significant between the EGB group and negative control group at 3 and 6 months after treatment.Conclusion：EGB significantly inhibited major periodontal pathogens and can be used as an adjuvant for periodontitis treatment.