Oral viral infections of adults

Viral infection and antiviral immunity in the oral cavity

Individual tissues have distinct antiviral properties garnered through various mechanisms, including physical characteristics, tissue-resident immune cells and commensal organisms. Although the oral mucosa has long been appreciated as a critical barrier tissue that is exposed to a continuous barrage of pathogens, many fundamental aspects of the antiviral immune response in this tissue remain unknown. Several viral pathogens, such as herpesviruses and human papillomaviruses, have been acknowledged both historically and at present for infections in the oral cavity that result in substantial clinical burden. However, recent viral outbreaks, including those with SARS-CoV-2 and mpox, featured oral symptoms even though these viruses are not generally considered oral pathogens. Ensuing studies have shown that the oral cavity is an important locale for viral infection and potential transmission of newly emergent or re-emergent pathogens, highlighting the need for an increased understanding of the mechanisms of antiviral immunity at this site. In this Review, we provide a broad overview of antiviral immune responses in the oral cavity and discuss common viral infections and their manifestations in the oral mucosa. In addition, we present current mouse models for the study of oral viral infections.

The role of viruses in oral mucosal lesions

The mucosa of the oral cavity is exposed to a large number of different microorganisms such as archaea, bacteria, fungi, parasites, and viruses. Among those, viruses cause specific infections, which can easily be transmitted from one person to another. The infectious route may not only include patients and their relatives but also the dental professional team. Thus, a wide knowledge regarding specific viral infections is crucial for the daily routine. Signs and symptoms of oral viral infections can be completely absent or develop into a pronounced clinical picture, so that early detection and information determine the further course of the infection and its influence on other inflammatory diseases, such as periodontitis, as well as the safety of family members and the social environment. As the clinical manifestation of viral infections may be highly variable leading to heterogenous mucosal lesions it is, in most cases, mandatory to differentiate them by specific microbiological tests in addition to clinical examination procedures. This article will give an overview of the role of viruses infecting the oral mucosa, and in addition, describe their clinical manifestation and management.

The Role of Viruses in Pulpal and Apical Disease: A Systematic Review

Apical lesions are diseases of infectious origin that can cause destruction of the surrounding periapical tissue, including bone tissue and periodontal ligaments, resulting in the loss of the affected teeth. Currently, the microorganisms present in pulp and apical disease are mostly studied as bacteria. However, in recent years, interest has been aroused in the study of viruses that could be present in apical lesions, and how these could affect the progression of disease. In the present study, we conducted a systematic review of the literature to evaluate and synthesize the scientific evidence on the presence of viruses and their possible role in pulpal and apical disease. This systematic review was performed according to the PRISMA reporting guidelines. The search for studies was performed in the PubMed and Web of Science databases. A total of seven studies published in the last 10 years were included. The types of samples used for virus analysis varied from one study to another. In all the included studies, the presence of any of the types of viruses studied was found, either in pulp or apical tissue. Herpesviridae family, Epstein-Barr virus (EBV) and Human cytomegalovirus (HCMV) stood out as the most commonly present in apical lesions. Further studies are required to clarify and understand the pathogenic role of viruses in pulpal and periapical disease.

Detection of Human Herpesviruses in Sera and Saliva of Asymptomatic HIV-Infected Individuals Using Multiplex RT-PCR DNA Microarray

Human herpesviruses (HHVs) are frequently linked to an increased risk of acquiring human immunodeficiency virus (HIV), and vice versa. This study aimed to detect human herpesvirus (HHV) members in the sera and saliva of asymptomatic HIV-infected individuals. Paired saliva and serum samples were obtained from 30 asymptomatic HIV-infected individuals. HHVs were detected with a multiplex reverse transcription-polymerase chain reaction (RT-PCR) DNA microarray Clart®Entherpex kit. A total of 30 subjects were enrolled: 23 (76.67%) men and 7 (23.33%) women. The present study showed that at least one or more HHV members were detected in the saliva and sera of all (100%) of the subjects. In the saliva, we detected herpes simplex virus 1 (HSV-1) 6.67%, herpes simplex virus 2 (HSV-2) 6.67%, Epstein-Barr virus (EBV) 86.67%, cytomegalovirus (CMV) 63.33%, HHV-6 (40%), and HHV-7 (83.33%). In the sera, HSV-2 (20%), EBV (30%), CMV (40%), HHV-6 (0%), and HHV-7 (76.67%) were found, but not HSV-1. VZV and HHV-8 were not detected in either the saliva or sera. EBV and HHV6 were significantly more prevalent in the saliva than they were in the sera of asymptomatic HIV-infected individuals (p < 0.05). However, no significant differences were found in the prevalence of HSV-1, EBV, CMV, HHV-6, and HHV-7 in the saliva and sera of asymptomatic HIV-infected individuals (p > 0.05). In conclusion, the multiplex RT-PCR DNA microarray can serve as a valuable diagnostic tool that can be used as a screening tool or a first-line test for HHVs infections.

TLR3 recognition of viral double-stranded RNA in human dental pulp cells is important for the innate immunity

Dental caries or trauma can expose human dental pulp cells (DPCs) to various oral microorganisms, which play an important role in the development of an innate immune response. In the present study, we examined the expression of Toll-like receptors (TLRs) for sensing microbe-associated molecular patterns in human DPCs. Interestingly, real-time PCR analysis demonstrated that TLR3 is the most highly expressed among 10 different TLRs in human DPCs. Poly(I:C), a representative TLR3 ligand mimicking viral double-stranded RNA, potently induced IL-8 expression in a time- and dose-dependent manner. Concordantly, poly(I:C) treatment substantially increased the expression of pro-inflammatory cytokines and chemokines such as IL-6, CCL2, and CXCL10. Human DPCs transfected with TLR3 siRNA exhibited decreased IL-8 production compared with non-targeting siRNA-transfected cells, suggesting that the expression of poly(I:C)-induced inflammatory cytokines is dependent on TLR3. IL-8 secretion induced by poly(I:C) was down-regulated by MAP kinase inhibitors, indicating that the MAP kinase pathway contributes to IL-8 production. Furthermore, C/EBPβ and NF-κB were essential transcriptional factors for poly(I:C)-induced IL-8 expression, as demonstrated by the transient transfection and reporter gene assay. Since lipoproteins are known as major immunostimulatory components of bacteria, human DPCs were treated with poly(I:C) together with Pam2CSK4, a synthetic lipopeptide mimicking bacterial lipoproteins. Pam2CSK4 and poly(I:C) co-treatment synergistically increased IL-8 production in comparison to Pam2CSK4 or poly(I:C) alone, implying that co-infection of viruses and bacteria can synergistically induce inflammatory responses in the dental pulp. Taken together, these results suggest that human DPCs potentially sense and respond to viral double-stranded RNAs, leading to effective induction of innate immune responses.

Association between human herpesviruses and multiple sclerosis: A systematic review and meta-analysis

AIM

The aim of this study was to investigate the prevalence and potential association between infection with different herpes viruses and multiple sclerosis (MS).

METHODS

A systematic literature search was performed by finding relevant cross-sectional and case-control studies from a large online database. Heterogeneity, Odds ratio (OR), and corresponding 95% Confidence interval (CI) were applied to all studies by meta-analysis and forest plots. The analysis was performed using Stata Software v.14.

RESULTS

One hundred and thirty-four articles (289 datasets) were included in the meta-analysis, 128 (245 datasets) of which were case/control and the rest were cross-sectional. The pooled prevalence of all human herpes viruses among MS patients was 50% (95% CI: 45-55%; I2 = 96.91%). In subgroup analysis, the pooled prevalence of Herpes simplex virus (HSV), Varicella-zoster virus (VZV), Epstein-Barr virus (EBV), Cytomegalovirus (CMV), Human herpes virus 6 (HHV-6), Human herpes virus 7 (HHV-7), and Human herpes virus 8 (HHV-8) was 32%, 52%, 74%, 41%, 39% 28%, and 28%, respectively. An association was found between infection with human herpes viruses and MS [summary OR 2.07 (95% CI (1.80-2.37); I2 = 80%)].

CONCLUSION

The results of the present study showed that EBV, VZV, and HHV-6 infection are associated with multiple sclerosis and can be considered as potential risk factors for MS. Although the exact molecular mechanism of the role of herpes viruses in the development of MS is still unknown, it seems that molecular mimicry, the release of autoreactive antibodies, and inflammation in the CNS following viral infection can be important factors in the induction of MS.

Viruses of the oral cavity: Prevalence, pathobiology and association with oral diseases

The human oral cavity contains a plethora of habitats and tissue environments, such as teeth, tongue, and gingiva, which are home to a rich microbial flora including bacteria, fungi, and viruses. Given the exposed nature of the mouth, oral tissues constantly encounter infectious agents, forming a complex ecological community. In the past, the discussion of microbiological aspects of oral disease has traditionally focused on bacteria and fungi, but viruses are attracting increasing attention as pathogens in oral inflammatory diseases. Therefore, understanding viral prevalence, pathogenicity, and preference regarding oral tissues is critical to understanding the holistic effects of viruses on oral infections. Recent investigations have demonstrated the abundance of certain viruses in oral inflammatory diseases, suggesting an association between viruses and disease. Human herpesviruses are the most extensively studied viruses in different oral inflammatory diseases. However, challenges in viral detection and the lack of reproducible in vitro and in vivo infection models have limited our progress in understanding viruses and their contribution to oral diseases. This review presents a summary of major mammalian viruses and associated diseases in the human oral cavity. The emergence of a recent pathogen SARS-CoV-2 and its tropism for salivary and periodontal tissues further highlights the relevance of the oral cavity in host-pathogen interaction. Understanding how these different viruses present clinically and influence oral health will advance our understanding of multifactorial oral diseases and their association with viruses.

Detection and quantification of Epstein-Barr virus, cytomegalovirus, and human herpesvirus-6 in stomach frozen tissue of chronic gastritis and gastric cancer patients

Human herpes viruses (HHVs) are among the most common infectious agents detected in the gastrointestinal tract that might be involved in oncogenesis and other gastrointestinal disorders. Although the link between the Epstein-Barr virus (EBV) and gastric cancer (GC) has been established, the role of the viruses in various stomach diseases remains unknown. The frequencies and viral copy number of EBV, cytomegalovirus (CMV), and human herpesvirus 6 (HHV-6) among 50 gastric cancer tumors and 105 chronic gastritis tissues were measured by quantitative real-time PCR. In the tumor specimens and the adjacent normal tissues EBV was found in 60% and 30.9%, CMV in 14% and 4.7%, and HHV-6 in 18%, and 14.2%, respectively. The detection rate of EBV and CMV was found to be significantly higher in tumor tissues relative to the adjacent normal tissues. Also, in chronic gastritis, the frequency of EBV, CMV, and HHV-6 was 19%, 12.3%, and 15.2%, respectively, compared with 16.4%, 1.1%, and 8.2% in their corresponding normal tissues. Here, the CMV frequency was found to be significantly higher in gastritis tissues relative to the adjacent normal tissues. Furthermore, viral load in both gastric cancer and gastritis groups was higher in either tumor or gastritis lesion compared with matched adjacent normal tissue. This study showed a clear association between gastric cancer with both EBV and CMV. Meanwhile, analyses revealed a strong association between the EBV, CMV, and HHV-6 viral loads with gastritis (P = 0.0026, P < 0.0001, and P = 0.0405, respectively). Our results suggest that these three viruses might contribute to the induction and development the gastritis and gastric cancer.

The human oral virome: Shedding light on the dark matter

Mediators of the initiation, development, and recurrence of periodontitis include the oral microbiome embedded in subgingival plaque and the host immune response to a dysbiosis within this dynamic and complex microbial community. Although mediators have been studied extensively, researchers in the field have been unable to fully ascribe certain clinical presentations of periodontitis to their nature. Emergence of high-throughput sequencing technologies has resulted in better characterization of the microbial oral dysbiosis that extends beyond the extensively studied putative bacterial periodontopathogens to a shift in the oral virome composition during disease conditions. Although the biological dark matter inserted by retroviruses was once believed to be nonfunctional, research has revealed that it encodes historical viral-eukaryotic interactions and influences host development. The objective of this review is to evaluate the proposed association of herpesviruses to the etiology and pathogenesis of periodontal disease and survey the highly abundant prokaryotic viruses to delineate their potential roles in biofilm dynamics, as well as their interactions with putative bacterial periodontopathogens and eukaryotic cells. The findings suggest that potential novel periodontal therapies targeting or utilizing the oral virome can alleviate certain clinical presentations of periodontitis. Perhaps it is time to embrace the viral dark matter within the periodontal environment to fully comprehend the pathogenesis and systemic implications of periodontitis.

Clinical Manifestations and Epigenetic Regulation of Oral Herpesvirus Infections

The oral cavity is often the first site where viruses interact with the human body. The oral epithelium is a major site of viral entry, replication and spread to other cell types, where chronic infection can be established. In addition, saliva has been shown as a primary route of person-to-person transmission for many viruses. From a clinical perspective, viral infection can lead to several oral manifestations, ranging from common intraoral lesions to tumors. Despite the clinical and biological relevance of initial oral infection, little is known about the mechanism of regulation of the viral life cycle in the oral cavity. Several viruses utilize host epigenetic machinery to promote their own life cycle. Importantly, viral hijacking of host chromatin-modifying enzymes can also lead to the dysregulation of host factors and in the case of oncogenic viruses may ultimately play a role in promoting tumorigenesis. Given the known roles of epigenetic regulation of viral infection, epigenetic-targeted antiviral therapy has been recently explored as a therapeutic option for chronic viral infection. In this review, we highlight three herpesviruses with known roles in oral infection, including herpes simplex virus type 1, Epstein–Barr virus and Kaposi’s sarcoma-associated herpesvirus. We focus on the respective oral clinical manifestations of these viruses and their epigenetic regulation, with a specific emphasis on the viral life cycle in the oral epithelium.

Expression of SARS-CoV-2 entry factors in human oral tissue

The distribution of cells expressing SARS‐CoV‐2 entry factor angiotensin‐converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2) in human oral tissues were tested. The investigation was conducted with normal flesh tissue and paraffin‐embedded specimens. The ACE2 and TMPRSS2 expression was detected with all subjects in the normal mucosa of the keratinized stratified squamous epithelia of the tongue and non‐keratinized stratified squamous epithelia of the lip and cheek. It was found that ACE2 is expressed in the cytoplasm and on the cell membrane mainly in the stratum granulosum of the epithelia while the TMPRSS2 is strongly expressed on the cell membrane mainly in the stratum granulosum and stratum spinosum, but not in the stratum basale. Antibodies’ reactions for ACE2 and TMPRSS2 were not observed in the nuclei or keratin layer. The expression of ACE2 and TMPRSS2 in the oral epithelia appears to be general, and the expression was also observed in the mucous and serous acini of the labial glands. The SARS‐CoV‐2 may transiently attach to the oral mucosa and the minor salivary glands which are present under all of the oral mucosa. The oral cavity can be considered an important organ for SARS‐CoV‐2 attachment and may provide a preventive medical avenue to guard against COVID‐19 by preventing saliva from scattering.

Epigenetic reprogramming in periodontal disease: Dynamic crosstalk with potential impact in oncogenesis

Periodontitis is a chronic multifactorial inflammatory disease associated with microbial dysbiosis and characterized by progressive destruction of the periodontal tissues. Such chronic infectious inflammatory disease is recognized as a major public health problem worldwide with measurable impact in systemic health. It has become evident that the periodontal disease phenotypes are not only determined by the microbiome effect, but the extent of the tissue response is also driven by the host genome and epigenome patterns responding to various environmental exposures. More recently there is mounting evidence indicating that epigenetic reprogramming in response to combined intrinsic and environmental exposures, might be particularly relevant due its plasticity and potential application towards precision health. The complex epigenetic crosstalk is reflected in the prognosis and progress of periodontal diseases and may also lead to a favorable landscape for cancer development. This review discusses epigenomics modifications focusing on the role of DNA methylation and pathways linking microbial infection and inflammatory pathways, which are also associated with carcinogenesis. There is a more clear vision whereas 'omics' technologies applied to unveil relevant epigenetic factors could play a significant role in the treatment of periodontal disease in a personalized mode, evidencing that public health approach should coexist with precision individualized treatment.

Periodontal herpesvirus morbidity and treatment

Four billion individuals worldwide have a history of periodontitis, with the poorest people in society most affected. Periodontitis can lead to unsightly drifting of teeth and tooth loss that may interfere with the wellbeing of daily living and has also been linked to at least 57 medical diseases and disabilities. The etiology of severe periodontitis includes active herpesviruses, specific bacterial pathogens, and destructive immune responses, but herpesviruses seem to be the major pathogenic determinant. Periodontal herpesviruses that disseminate via the systemic circulation to nonoral sites may represent a major link between periodontitis and systemic diseases. Current treatment of periodontitis focuses almost exclusively on bacterial biofilm and will require revision. Periodontal therapy that targets both herpesviruses and bacterial pathogens can provide long-term clinical improvement and potentially reduces the risk of systemic diseases. Molecular diagnostic tests for periodontal pathogens may enable early microbial identification and preemptive therapy. This review details an efficient and reliable anti-infective treatment of severe periodontitis that can be carried out in minimal time with minimal cost.

New Viral Facets in Oral Diseases: The EBV Paradox

The oral cavity contributes to overall health, psychosocial well-being and quality of human life. Oral inflammatory diseases represent a major global health problem with significant social and economic impact. The development of effective therapies, therefore, requires deeper insights into the etiopathogenesis of oral diseases. Epstein–Barr virus (EBV) infection results in a life-long persistence of the virus in the host and has been associated with numerous oral inflammatory diseases including oral lichen planus (OLP), periodontal disease and Sjogren’s syndrome (SS). There is considerable evidence that the EBV infection is a strong risk factor for the development and progression of these conditions, but is EBV a true pathogen? This long-standing EBV paradox yet needs to be solved. This review discusses novel viral aspects of the etiopathogenesis of non-tumorigenic diseases in the oral cavity, in particular, the contribution of EBV in OLP, periodontitis and SS, the tropism of EBV infection, the major players involved in the etiopathogenic mechanisms and emerging contribution of EBV-pathogenic bacteria bidirectional interaction. It also proposes the involvement of EBV-infected plasma cells in the development and progression of oral inflammatory diseases. A new direction for preventing and treating these conditions may focus on controlling pathogenic EBV with anti-herpetic drugs.

Detection of herpes viruses in Ghanaian patients with periodontitis

AIM

The complexity of periodontitis in both etiology and progression has raised many questions, necessitating enormous research in recent years. The aim of the present study was to detect the presence of herpes viruses in Ghanaian patients diagnosed with periodontitis.

METHODS

Thirty-one patients were included in the study; 21 with periodontitis classified into localized chronic, generalized, and aggressive periodontitis, and 10 without the disease were used as controls. Subgingival samples were collected, followed by DNA extraction. Multiplex polymerase chain reaction was used to amplify viral DNA for the detection of herpes viruses. Data was analyzed using Stata 14.

RESULTS

The mean age for patients with aggressive periodontitis was 32.2 years (standard deviation [SD]: 8.50), while those for localized chronic periodontitis and generalized chronic periodontitis were 40.6 years (SD: 7.83) and 46.3 years (SD: 12.12), respectively. Viruses were detected only among patients clinically diagnosed with aggressive periodontitis. Of the total number of aggressive periodontitis patients, herpes simplex virus 1 (HSV-1) and Epstein-Barr virus (HBV) were found in four (44%) and one (11%), respectively. The mean age for patients found to have HSV-1 or EBV was 29 years (SD: 6.93).

CONCLUSION

We found HSV-1 and EBV in the subgingival plaque samples of Ghanaian patients clinically diagnosed with aggressive periodontitis. While our finding requires further investigation, the role of HSV in periodontitis, if elucidated, could transform and inform the clinical management of the condition.

Modulation of salivary cytokines in response to alcohol, tobacco and caffeine consumption: a pilot study

It has been shown that long-term stimulant consumption alters the biological and microbiological status of the oral cavity. We present a pilot study describing stimulant-specific oral immunomodulation in the oral cavity. Changes in salivary cytokine levels in response to long-term alcohol, tobacco and caffeine were identified. Volunteers were recruited from amongst the patients visiting University Dental Clinic of CEU Cardenal Herrera University (Alfara del Patriarca, Spain). Participants were grouped according to their self-reported levels of consumption of either caffeine, alcohol or tobacco (control group volunteers were non-consumers of all three). Informed consent was provided and stimulated saliva samples were obtained and assayed for interleukin-1α IL-1α), Tumor Necrosis Factor α (TNF-α) and Interferon γ IFN-γ). Long-term, high-level consumers of alcohol or tobacco exhibited elevated salivary concentrations of the three inflammatory cytokines with respect to control values. Specifically, IL-1α was found to be elevated in alcohol users whilst IFN-γ concentration higher in tobacco users versus controls. Long-term caffeine consumers displayed elevated levels of IFN-γ and TNF-α, whereas IL-1α levels were reduced with respect to control volunteers. This pilot study demonstrates that salivary cytokines can be modulated in response to quantity and duration of alcohol, caffeine or tobacco consumption.

Periodontitis: facts, fallacies and the future

This volume of Periodontology 2000 represents the 25th anniversary of the Journal, and uses the occasion to assess important advancements in periodontology over the past quarter-century as well as the hurdles that remain. Periodontitis is defined by pathologic loss of the periodontal ligament and alveolar bone. The disease involves complex dynamic interactions among active herpesviruses, specific bacterial pathogens and destructive immune responses. Periodontal diagnostics is currently based on clinical rather than etiologic criteria, and provides limited therapeutic guidance. Periodontal causative treatment consists of scaling, antiseptic rinses and occasionally systemic antibiotics, and surgical intervention has been de-emphasized, except perhaps for the most advanced types of periodontitis. Plastic surgical therapy includes soft-tissue grafting to cover exposed root surfaces and bone grafting to provide support for implants. Dental implants are used to replace severely diseased or missing teeth, but implant overuse is of concern. The utility of laser treatment for periodontitis remains unresolved. Host modulation and risk-factor modification therapies may benefit select patient groups. Patient self-care is a critical part of periodontal health care, and twice-weekly oral rinsing with 0.10-0.25% sodium hypochlorite constitutes a valuable adjunct to conventional anti-plaque and anti-gingivitis treatments. A link between periodontal herpesviruses and systemic diseases is a strong biological plausibility. In summary, research during the past 25 years has significantly changed our concepts of periodontitis pathobiology and has produced more-effective and less-costly therapeutic options.

Detection of a new species of torque teno mini virus from the gingival epithelium of patients with periodontitis

We describe a novel species of torque teno mini virus called TTMV-204, which was isolated from the gingival epithelium of patients with periodontitis and characterized using viral metagenomics. The sequence of the full genome is 2824 nt in length. Phylogenetic analysis and genetic analyses show classic Betatorquevirus species organization with less than 40% amino acid similarity in ORF1. The prevalence of TTMV-204 in the periodontitis patient population was 18.75% (15/80), which was higher than in periodontally healthy individuals (10.00%, 10/80). However, the difference of the TTMV-204 prevalence between two groups was not statistically significant (p = 0.115). Further investigation is required to determine whether this new virus is associated with inflammation.

Saliva and viral infections

Over the last 10 years there have been only a handful of publications dealing with the oral virome, which is in contrast to the oral microbiome, an area that has seen considerable interest. Here, we survey viral infections in general and then focus on those viruses that are found in and/or are transmitted via the oral cavity; norovirus, rabies, human papillomavirus, Epstein‐Barr virus, herpes simplex viruses, hepatitis C virus, and HIV. Increasingly, viral infections have been diagnosed using an oral sample (e.g. saliva mucosal transudate or an oral swab) instead of blood or urine. The results of two studies using a rapid and semi‐quantitative lateral flow assay format demonstrating the correlation of HIV anti‐IgG/sIgA detection with saliva and serum samples are presented. When immediate detection of infection is important, point‐of‐care devices that obtain a non‐invasive sample from the oral cavity can be used to provide a first line diagnosis to assist in determining appropriate counselling and therapeutic path for an increasing number of diseases.

Advanced drug delivery systems for local treatment of the oral cavity

Good oral health is of major importance for general health and well-being. Several innovative drug delivery systems have been developed for the local treatment and prevention of various diseases in the oral cavity. However, there are currently few optimal systems and many therapeutic challenges still remain, including low drug efficacy and retention at targeted site of action. The present review provides an insight into the latest drug delivery strategies for the local treatment and prevention of the four most common oral pathologies, namely, dental caries, periodontitis, oral mucosal infections and oral cancer. The potential of bioadhesive formulations, nanoparticulate platforms, multifunctional systems and photodynamic methodologies to improve therapy and prophylaxis in future local applications for the oral cavity will be discussed.

A novel species of torque teno mini virus (TTMV) in gingival tissue from chronic periodontitis patients

A new species of torque teno mini virus, named TTMV-222, was detected in gingival tissue from periodontitis patients using a viral metagenomics method. The 2803-nucleotide genome of TTMV-222 is closely related to TTMV1-CBD279, with 62.6% overall nucleotide similarity. Genetic analyses of the new virus genome revealed a classic genomic organization but a weak identity with known sequences. The prevalence of TTMV-222 in the periodontitis group (n = 150) was significantly higher than that in the healthy group (n = 150) (p = 0.032), suggesting that the new virus may be associated with inflammation in chronic periodontitis patients. However, this finding requires further investigation.

LACK OF ASSOCIATION BETWEEN HERPESVIRUS DETECTION IN SALIVA AND GINGIVITIS IN HIV‑INFECTED CHILDREN

The aims of this study were to compare the detection of human herpesviruses (HHVs) in the saliva of HIV-infected and healthy control children, and to evaluate associations between viral infection and gingivitis and immunodeficiency. Saliva samples were collected from 48 HIV-infected and 48 healthy control children. Clinical and laboratory data were collected during dental visits and from medical records. A trained dentist determined gingival indices and extension of gingivitis. Saliva samples were tested for herpes simplex virus types 1 and 2 (HSV-1 and HSV-2), varicella zoster virus (VZV), Epstein-Barr virus (EBV), and cytomegalovirus (CMV) by nested polymerase chain reaction assays. Thirty-five HIV-infected and 16 control children had gingivitis. Seventeen (35.4%) HIV-infected children and 13 (27%) control children were positive for HHVs. CMV was the most commonly detected HHV in both groups (HIV-infected, 25%; control, 12.5%), followed by HSV-1 (6.2% in both groups) and HSV-2 (HIV-infected, 4.2%; control, 8.3%). The presence of HHVs in saliva was not associated with the presence of gingivitis in HIV-1-infected children (p = 0.104) or healthy control children (p = 0.251), or with immunosuppression in HIV-infected individuals (p = 0.447). Gingivitis was correlated with HIV infection (p = 0.0001). These results suggest that asymptomatic salivary detection of HHVs is common in HIV-infected and healthy children, and that it is not associated with gingivitis.

Association between Herpesviruses and Chronic Periodontitis: A Meta-Analysis Based on Case-Control Studies

OBJECTIVE

Numerous studies have investigated the associations between herpesviruses and chronic periodontitis; however, the results remain controversial. To derive a more precise estimation, a meta-analysis on all available studies was performed to identify the association between herpesviruses and chronic periodontitis.

METHODS

A computerized literature search was conducted in December 2014 to identify eligible case-control studies from the PUBMED and EMBASE databases according to inclusion and exclusion criteria. Data were extracted and pooled odds ratios (OR) with 95% confidence intervals (CI) were used to assess the association between herpesviruses and risk of chronic periodontitis. A fixed or random effects model was determined based on a heterogeneity test. Sensitivity analysis was conducted to investigate stability and reliability. Publication bias was investigated using the Begg rank correlation test and Egger's funnel plot.

RESULTS

Ten eligible studies were included to investigate the association between Epstein-Barr virus (EBV) and chronic periodontitis. The results showed that EBV has a significant association with chronic periodontitis compared with periodontally healthy group (OR = 5.74, 95% CI = 2.53-13.00, P<0.001). The association between human cytomegalovirus (HCMV) and chronic periodontitis was analyzed in 10 studies. The pooled result showed that HCMV also has a significant association with chronic periodontitis (OR = 3.59, 95% CI = 1.41-9.16, P = 0.007). Similar results were found in the sensitivity analyses. No significant publication bias was observed. Two eligible studies were included to investigate the association between herpes simplex virus (HSV) and chronic periodontitis risk. The association between HSV and chronic periodontitis was inconclusive (OR = 2.81 95% CI = 0.95-8.27, P = 0.06). Only one included study investigated the association between human herpesvirus 7 (HHV-7) and chronic periodontitis risk (OR = 1.00, 95% CI = 0.21-4.86).

CONCLUSION

The findings of this meta-analysis suggest that two members of the herpesvirus family, EBV and HCMV, are significantly associated with chronic periodontitis. There is insufficient evidence to support associations between HSV, HHV-7 and chronic periodontitis.

Biology and pathogenesis of cytomegalovirus in periodontal disease

Human periodontitis is associated with a wide range of bacteria and viruses and with complex innate and adaptive immune responses. Porphyromonas gingivalis, Tannerella forsythia, Aggregatibacter actinomycetemcomitans, Treponema denticola, cytomegalovirus and other herpesviruses are major suspected pathogens of periodontitis, and a combined herpesvirus–bacterial periodontal infection can potentially explain major clinical features of the disease. Cytomegalovirus infects periodontal macrophages and T‐cells and elicits a release of interleukin‐1β and tumor necrosis factor‐α. These proinflammatory cytokines play an important role in the host defense against the virus, but they also have the potential to induce alveolar bone resorption and loss of periodontal ligament. Gingival fibroblasts infected with cytomegalovirus also exhibit diminished collagen production and release of an increased level of matrix metalloproteinases. This article reviews innate and adaptive immunity to cytomegalovirus and suggests that immune responses towards cytomegalovirus can play roles in controlling, as well as in exacerbating, destructive periodontal disease.

Viruses in pulp and periapical inflammation: a review

The presence of viruses in endodontic disease has been studied in the last decade. Their presence is associated with periapical radiolucency and with clinical findings, such as pain. The aim of this review is to analyze the scientific evidence currently published about viruses in pulp and periapical inflammation, and its possible clinical implications. A literature review was carried out using the Medline/Pubmed database. The search was performed, in English and Spanish, using the following keyword combinations: virus AND endodontic; virus AND periapical; virus AND pulpitis; herpesvirus AND periapical; papillomavirus AND periapical. We subsequently selected the most relevant studies, which complied with the search criterion. A total of 21 articles were included, of which 18 detected the present of viruses in the samples. In 3 of the studies, viral presence was not found in the samples studied. The Epstein-Barr virus was found in about 41 % of cases compared to controls, in which it was present in about 2 %. The main association between viruses and endodontic pathosis is between Cytomegalovirus and Epstein-Barr virus; these are found in 114 of the 406 samples of different endodontic pathosis. Some evidence supports that the Epstein-Barr virus is present in a significant number of endodontic diseases, without exact knowledge of their action in these diseases.

Alzheimer's disease and chronic periodontitis: is there an association?

Alzheimer's disease, an affliction of old age, is one of the leading causes for dementia worldwide. Various risk factors including family history, genetics and infections have been implicated in its pathogenesis. The cognitive decline in this condition is mainly a result of the formation of amyloid deposits that provoke neuroinflammation, ultimately resulting in cell death. Recently, an association between peripheral inflammation and Alzheimer's disease was hypothesized. It was suggested that chronic systemic inflammation worsened the inflammatory processes in the brain. This was mainly attributed to increased levels of pro-inflammatory mediators, such as interleukin-1, interleukin -6 and tumor necrosis factor-α in the plasma. As chronic periodontitis is a widespread peripheral immunoinflammatory condition, it has been proposed to play a significant role in the aggravation of Alzheimer's disease. With this background, the current review focuses on the relationship between Alzheimer's disease and chronic periodontitis, and its therapeutic implications.

Orofacial viral infections--an update for clinicians

Orofacial viral infections may be less common but appear in different clinical forms. Often these infections get initially treated by antibiotics which obviously will have limited or no effect. The authors review the current concepts of orofacial viral infections, causative agents, their classification and clinical manifestations and a basis for treatment.

CLINICAL RELEVANCE

Most viral infections do not require any specific treatment except in patients who are immunosuppressed or immunodeficient. Appropriate diagnosis and timely management of orofacial viral lesions are important irrespective of whether it is localized or a manifestation of a systemic infection.

Detection of human cytomegalovirus and Epstein-Barr Virus in symptomatic and asymptomatic apical periodontitis lesions by real-time PCR

OBJECTIVES

Recent studies have investigated the occurrence of human cytomegalovirus and Epstein-Barr Virus in samples from apical periodontitis lesions and a role in the pathogenesis of this disease has been suggested. Because genotype distribution and seroprevalence of EBV and HCMV differ among populations, it is important to determine the presence of these viruses in endodontic periapical lesions of different populations. The aims of this study were to determine the presence of HCMV and EBV DNAs in samples from Turkish patients with symptomatic and asymptomatic apical periodontitis lesions using real-time polymerase chain reaction method and to evaluate their presence in both symptomatic and asymptomatic apical periodontitis lesions.

STUDY DESIGN

Periapical samples were collected from 12 asymptomatic and 16 symptomatic periapical lesions in conjunction with apicectomy. HCMV and EBV DNAs were identified in the samples by real-time PCR. The chi-squared test with Yates's correction or the Fisher's exact test was used to analyse the significance of differences.

RESULTS

HCMV DNA was detected in 10 of the 16 (62.5%) symptomatic and in five of the 12 (41.7 %) asymptomatic periapical study lesions. The EBV DNA was identified in seven of the 16 (43.7 %) symptomatic and three of the 12 (25 %) asymptomatic periapical lesions. The difference in occurrence of HCMV and EBV DNA between symptomatic and asymptomatic periapical lesions was not statistically significant. (All comparisons have p > 0.05).

CONCLUSION

Our findings suggest that HCMV and EBV is a frequent inhabitant of both symptomatic and asymptomatic apical periodontitis lesions of endodontic origin in Turkish population.

Low-cost periodontal therapy

Periodontitis is a complex infectious disease that affects low-income individuals disproportionately. Periodontitis is associated with specific bacterial species and herpesviruses, and successful prevention and treatment of the disease is contingent upon effective control of these pathogens. This article presents an efficacious, highly safe, minimally invasive, practical and low-cost periodontal therapy that involves professional and patient-administered mechanical therapy and antimicrobial agents. The major components are scaling for calculus removal, periodontal pocket irrigation with potent antiseptics, and treatment with systemic antibiotics for advanced disease. Povidone-iodine and sodium hypochlorite have all the characteristics for becoming the first-choice antiseptics in the management of periodontal diseases. Both agents show excellent antibacterial and antiviral properties, are readily available throughout the world, have been safely used in periodontal therapy for decades, offer significant benefits for individuals with very limited financial resources, and are well accepted by most dental professionals and patients. Four per cent chlorhexidine applied with a toothbrush to the most posterior part to the tongue dorsum can markedly reduce or eliminate halitosis in most individuals. Systemic antibiotics are used to treat periodontopathic bacteria that are not readily reached by topical therapy, such as pathogens within gingival tissue, within furcation defects, at the base of periodontal pockets, and on the tongue, tonsils and buccal mucosae. Valuable antibiotic therapies are amoxicillin-metronidazole (250 mg of amoxicillin and 250 mg of metronidazole, three times daily for 8 days) for young and middle-aged patients, and ciprofloxacin-metronidazole (500 mg of each, twice daily for 8 days) for elderly patients and for patients in developing countries who frequently harbor enteric rods subgingivally. Scaling to remove dental calculus and the prudent use of inexpensive antimicrobial agents can significantly retard or arrest progressive periodontitis in the great majority of patients.

Correlation of cytomegalovirus and human herpesvirus 7 with CD3+ and CD3+ CD4+ cells in chronic periodontitis patients

BACKGROUND AND OBJECTIVE

Human chronic periodontitis is an inflammatory process characterized by dense accumulation of immune cells in the periodontal tissue. The periodontitis can lead to loss of teeth in the patient and the pathogenesis of this disease is not completely known. This study tested the hypothesis that chronic periodontitis-affected sites can harbor betaherpesviruses and that viruses are linked to a profile of the inflammatory infiltrate.

MATERIAL AND METHODS

Biopsies of periodontal tissue were taken from periodontitis-affected patients and from healthy subjects. Immunohistochemistry was performed to count CD19(+) B cells, CD3(+) total T cells, T-CD4(+) and T-CD8(+) cell subsets, and PCR was performed to detect cytomegalovirus and human herpesvirus 6 and 7 in the samples. One slide of each sample was stained with Giemsa for histopathological examination and to evaluate the quality of the cellular infiltrate.

RESULTS

As expected, tissues collected from healthy subjects presented no significant level of inflammatory infiltration and were therefore excluded from immunostaining procedures. Results showed that CD19(+) B cells were in higher number than CD3(+) T cells in the periodontitis-affected tissue, but this was not statistically significant. The T-CD4(+) lymphocyte subset was significantly higher than the T-CD8(+) lymphocyte subset (p = 0.004) in the samples. Cytomegalovirus and human herpesvirus 7 were found at periodontitis-affected sites, but not in tissue collected from healthy subjects (p = 0.04 and p = 0.04, respectively). Human herpesvirus 6 was rarely detected. We found a correlation between cytomegalovirus and lower CD19(+) /CD3(+) ratios (ratio < 0.9, p = 0.003) and between human herpesvirus 7 and lower CD19(+) /CD3(+) ratios (ratio < 0.9, p = 0.003) and higher CD4(+) /CD8(+) ratios (ratio > 1.1, p = 0.002).

CONCLUSION

This study shows that cytomegalovirus and human herpesvirus 7 can be present at periodontitis-affected sites but are uncommon at healthy periodontal sites. Moreover, our data suggest that cytomegalovirus can be related to an inflammatory infiltrate with predominance of CD3(+) T cells, whereas human herpesvirus 7 can be associated with an infiltrate with predominance of T-CD4(+) cells. However, further studies are necessary to support this hypothesis. Herpesviruses could play a role in human chronic periodontitis by modulation of the T cell response.

Herpesvirus carriage in saliva and posttreatment apical periodontitis: searching for association

OBJECTIVE

Herpesvirus infection can cause immunosuppression and then act as a modifier of apical periodontitis, influencing the disease severity and response to treatment. The purpose of this study was to investigate if herpesvirus infection, as inferred by salivary carriage, may influence the endodontic treatment outcome.

STUDY DESIGN

The study population included 72 patients who had root canals treated more than 1 year previously because of necrotic pulps and apical periodontitis. At the follow-up examination, 27 of these patients presented with posttreatment apical periodontitis (failure) and 45 individuals exhibited healed/healing periradicular tissues (success). Saliva was collected from these individuals, DNA was extracted, subjected to multiple displacement amplification, and screened by polymerase chain reaction (PCR) assays for the presence of 6 herpesviruses: herpes simplex virus types 1 and 2 (HSV-1/2), Epstein-Barr virus (EBV), human cytomegalovirus (HCMV), human herpesvirus-6 (HHV-6), and human herpesvirus-8 (HHV-8).

RESULTS

Except for HSV-1/2, all other herpesviruses were detected in saliva from both healed/healing and diseased groups. HHV-8 was the most frequent herpesvirus found in saliva (84% in success, 89% in failure), followed by HCMV (22% in success, 30% in failure), EBV (16% in success, 18.5% in failure) and HHV-6 (7% in success, 15% in failure). No significant association of herpesvirus carriage in saliva with poor treatment outcome was discernible in the population studied (P > .05).

CONCLUSIONS

Data from the present study suggest that herpesvirus infection may not influence the outcome of endodontic treatment. Further longitudinal studies are warranted to confirm these findings.

Local drug delivery for oral mucosal diseases: challenges and opportunities

There are few topical formulations used for oral medicine applications most of which have been developed for the management of dermatological conditions. As such, numerous obstacles are faced when utilizing these preparations in the oral cavity, namely enzymatic degradation, taste, limited surface area, poor tissue penetration and accidental swallowing. In this review, we discuss common mucosal diseases such as oral cancer, mucositis, vesiculo-erosive conditions, infections, neuropathic pain and salivary dysfunction, which could benefit from topical delivery systems designed specifically for the oral mucosa, which are capable of sustained release. Each condition requires distinct penetration and drug retention profiles in order to optimize treatment and minimize side effects. Local drug delivery may provide a more targeted and efficient drug-delivery option than systemic delivery for diseases of the oral mucosa. We identify those mucosal diseases currently being treated, the challenges that must be overcome and the potential of novel therapies. Novel biological therapies such as macromolecular biological drugs, peptides and gene therapy may be of value in the treatment of many chronic oral conditions and thus in oral medicine if their delivery can be optimized.

Identification of herpesviruses types 1 to 8 and human papillomavirus in acute apical abscesses

INTRODUCTION

It has been suggested that viruses, especially herpesviruses, can play a role in the pathogenesis of marginal and apical periodontitis. This study aimed to detect herpesviruses types 1 to 8, namely herpes simplex virus (HSV-1/2), varicella zoster virus (VZV), Epstein-Barr virus (EBV), human cytomegalovirus (HCMV), human herpesvirus-6 (HHV-6), human herpesvirus-7 (HHV-7), and human herpesvirus-8 (HHV-8) as well as human papillomavirus (HPV) in acute apical abscesses.

METHODS

Twenty-four samples were taken by aspiration of the purulent exudate from acute apical abscesses. DNA extracted from clinical samples served as a template in single or nested polymerase chain reaction (PCR) assays for the detection of the target viruses.

RESULTS

Control PCR reactions with β-globin gene primers revealed that all samples but one had detectable human DNA. Of the 23 abscess samples positive for the β-globin gene, 14 (61%) were positive for at least one of the target human viruses. Thirteen (56.5%) cases had herpesvirus: HHV-8 occurred in 11 (48%), VZV and HHV-6B in two (9%), and HHV-7 and HSV-1/2 in one (4%). EBV and HCMV were not present in any of the examined samples. HPV was detected in three (13%) abscess samples. Viral coinfection was found in five cases, with one case harboring three of the targeted viruses.

CONCLUSION

A large number of abscess samples were positive for at least one target virus. Unexpectedly, HHV-8 was for the first time detected and in a high prevalence. Papillomavirus and other herpesviruses were also found for the first time in endodontic abscesses. Although these findings suggest an association, the specific role of viruses in the pathogenesis of acute apical abscesses awaits further clarification.

The role of viruses in oral disease

The focus has traditionally been on bacteria and fungi when discussing microbiological aspects of oral disease. Viruses are probably more involved in diseases associated with the oral cavity than has been previously thought. The role of several viruses in ulceration is well known, but viruses of the herpes family may play a role in periodontitis, and papillomaviruses are probably involved in oral cancer. This review offers a brief introduction to virology before discussing the role of the more relevant viruses in oral disease. As to clinical application, it is concluded that the anti-herpes medication may, in some cases, be relevant in treating periodontitis, while papillomavirus vaccine would be expected to decrease the prevalence of oral cancer.

Periodontitis lesions are the main source of salivary cytomegalovirus

BACKGROUND

Herpesviruses play causal or cooperative roles in childhood infections, tumorigenesis, ulcerogenesis, and periodontitis. Saliva is a common vehicle of herpesvirus horizontal transmission, but the source of salivary herpesviruses remains obscure. To evaluate the significance of periodontal disease in shedding of oral herpesviruses, this study determined the genome-copy counts of human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV) in whole saliva of subjects with periodontitis, gingivitis, or no natural teeth.

METHODS

Whole saliva was collected from 14 periodontitis patients, 15 gingivitis patients and 13 complete denture wearers. The study subjects were systemically healthy and had not received periodontal treatment in the past 3 months. Real-time TaqMan polymerase chain reaction was used to determine the salivary load of HCMV and EBV.

RESULTS

Salivary HCMV was detected in seven (50%) periodontitis patients, but not in any gingivitis or edentulous subjects (P < 0.001). Salivary EBV was detected in 11 (79%) periodontitis patients, in five (33%) gingivitis patients, and in seven (54%) edentulous subjects (P = 0.076). Salivary samples showed copy counts of HCMV in the range of 3.3 x 10(3)-4.2 x 10(4)/ml and of EBV in the range of 3.6 x 10(2)-1.6 x 10(9)/ml.

CONCLUSIONS

HCMV and EBV are commonly present in the saliva of periodontitis patients. Periodontitis lesions of systemically healthy subjects seem to constitute the main origin of salivary HCMV, but do not comprise the sole source of salivary EBV.