Herpesviral-bacterial synergy in the pathogenesis of apical periodontitis: New insights and future perspectives

Effects of Herpesviruses on Proinflammatory Cytokines in Chronic Periapical Lesions

BACKGROUND Apical periodontitis is caused by infected dental pulp and may be associated with dental caries or trauma, which can destroy periradicular tissues. This study included periapical tissue of patients with chronic apical periodontitis and aimed to evaluate the presence of cytomegalovirus (CMV) and Epstein-Barr virus (EBV) using polymerase chain reaction (PCR), and to determine the levels of inflammatory cytokines using enzyme-linked immunoassay (ELISA). MATERIAL AND METHODS A total of 79 patients participated in this study. Periapical lesions were taken from the tooth roots indicated for extraction, and were divided into 2 groups: symptomatic and asymptomatic. PCR was used to identify HCMV and EBV. Interleukin 6 (IL-6), interleukin 8 (IL-8), tumor necrosis factor-alpha (TNF-alpha), and transforming growth factor beta-1 (TGFß-1) were determined using ELISA. RESULTS The occurrence of HCMV (P<0.05) and dual HCMV/EBV infection (P<0.05) was significantly more frequent in symptomatic lesions compared to asymptomatic. The concentrations of IL-6, IL-8, and TNF-alpha were significantly higher in virus-positive lesions compared to virus-negative ones (P<0.05); especially high cytokine levels were found in lesions with dual HCMV/EBV infection (P<0.05). The level of TGF-ß1 was higher in virus-positive compared to virus-negative lesions, but the difference was significant only in lesions with dual HCMV/EBV infection (P<0.05). CONCLUSIONS The higher prevalence of herpesviruses in symptomatic lesions compared to asymptomatic ones indicates their important role in pathogenesis of periapical lesions. Expression of TNF-alpha, IL-6, and IL-8 may be of importance in the development and clinical features of herpesvirus-infected lesions, while TGF-ß1 appears to be of no significance.

Association between virus infection and periodontitis: Evidence from the National Health and Nutrition Examination Survey 2009-2014

Periodontitis is a cumulative inflammatory disease associated with multiple health conditions and various systemic diseases. As a common disease, virus infection along with its consequences has become a serious health burden. The study aims to evaluate the relationship between common viruses including hepatitis virus, human immunodeficiency virus (HIV), herpes simplex virus (HSV), human papillomavirus (HPV), and periodontitis. The data from the US National Health and Nutrition Examination Survey (NHANES) 2009-2014 was adopted and screened through, including 10 714 participants. Generalized linear regression was conducted to verify the relationships between the virus infections and periodontitis. Moreover, we also performed analyses in age and gender subgroups. The results suggested that the infection of HCV, HSV-1, and HSV-2 was significantly associated with the prevalence of periodontitis (odds ratio [OR] 1.46, 95% confidence interval [CI] 1.26-1.70; OR 1.09, 95% CI 1.05-1.13; OR 1.06, 95% CI 1.01 - 1.11, respectively) and risk of developing moderate or severe periodontitis (OR 1.51, 95% CI 1.29-1.77; OR 1.08, 95% CI 1.04-1.12; OR 1.05, 95% CI 1.01-1.10, respectively) after adjusting all relevant co-factors. Subgroup analyses revealed a steady association between periodontitis and hepatitis C virus (HCV) or HSV-1 infection, while the relationship between HSV-2 and HPV infection can also be found in some subgroups. The presence of HCV and HSV infection was found to be significantly associated with the prevalence of periodontitis, including moderate or severe cases. Moreover, the association of periodontitis and HPV infection can also be observed in people < 35 years.

Herpes simplex virus type 1 in periapical pathoses: Systematic review and meta-analysis

OBJECTIVES

The objective of this systematic review and meta-analysis of observational studies was to assess whether herpes simplex virus type 1 (HSV-1) can infect endodontic periapical lesions.

MATERIALS AND METHODS

Studies with cross-sectional design investigating HSV-1 in periapical tissues of patients with symptomatic and asymptomatic acute and chronic apical periodontitis were searched through MEDLINE, Scopus, Embase, Web of Science, and Google Scholar. Pooled HSV-1 prevalence proportion with 95% confidence interval (95CI) in periapical lesions was assessed with both fixed-effect and random-effects models, with/without adjustment for study quality and publication bias. Result robustness was investigated through sensitivity and subgroup analyses.

RESULTS

Literature search, performed twice, provided 84 items, and eight remained for the meta-analysis; globally, there were 194 patients mostly adults. The pooled HSV-1 prevalence proportions, assessed with various methods, were 6.9% (95CI, 3.8-11.3%, fixed-effect); 6.8% (95CI, 3.6-11.0%, random-effects); 8.1% (95CI, 4.4-14.5%, quality-adjusted); and 4.8% (95CI, 2.0-11.4%; adjusted for small-study effect).

CONCLUSIONS

The results indicated that HSV-1 can colonize the periapical tissues of 3%-11% patients with periapical diseases. Such data do not imply a causative role of HSV-1 in disease development and advancement. Well-designed and large-sized prospective cohort studies should be added in the literature panorama.

Herpesviruses in Periodontitis: An Umbrella Review

BACKGROUND

Despite numerous studies indicating a high prevalence of herpesviruses in both apical and marginal periodontitis samples, their exact role in the pathogenesis of a periodontal disease is still unclear.

OBJECTIVE

This umbrella review aimed to summarize data on herpesviruses detection in marginal periodontitis (MP) and apical periodontitis of endodontic origin (APEO) samples.

METHODS

The study protocol has been drafted a priori and registered to the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42020215922). The literature search was conducted using the following electronic databases: Clarivate Analytics' Web of Science, Scopus, PubMed and Cochrane Database of Systematic Reviews, from inception to October 2020, with no language restrictions. Systematic reviews with or without meta-analysis that evaluated the association between the occurrence of herpesviruses and different forms of periodontal diseases were included. Other types of studies, including narrative reviews, were excluded. Two reviewers independently performed a literature search, data extraction, and quality assessment of included studies. Any disagreements or doubts were resolved by a third reviewer. The quality of the reviews was assessed using the AMSTAR 2 tool (A measurement tool to assess systematic reviews).

RESULTS

Six systematic reviews were included in the current review. One was graded as high quality, another one was graded as moderate quality, whereas the other four were graded as critically low-quality reviews. The presence of herpesviruses in subgingival samples was associated with an increased risk of MP, supported by the corresponding meta-analyses. Although the association was strong (OR > 3.0), the confidence intervals were wide, heterogeneity was significant, and studies were of small sample size. In addition, publication bias was detected. Contrary, data from systematic reviews that assessed APEO and herpesviruses did not show any significant associations.

CONCLUSIONS

Low-quality studies with high uncertainty suggest a strong association between herpesviruses and MP, but not with APEO.