Herpesviral-bacterial Coinfection in Periapical Pathosis

Herpesviruses and SARS-CoV-2: Viral Association with Oral Inflammatory Diseases

The oral cavity is a niche for diverse microbes, including viruses. Members of the Herpesviridae family, comprised of dsDNA viruses, as well as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), an ssRNA virus, are among the most prevalent viruses infecting the oral cavity, and they exhibit clinical manifestations unique to oral tissues. Viral infection of oral mucosal epithelia triggers an immune response that results in prolonged inflammation. The clinical and systemic disease manifestations of HHV have been researched extensively, and several recent studies have illuminated the relationship between HHV and oral inflammatory diseases. Burgeoning evidence suggests the oral manifestation of SARS-CoV-2 infection includes xerostomia, dysgeusia, periodontal disease, mucositis, and opportunistic viral and bacterial infections, collectively described as oral post-acute sequelae of COVID-19 (PASC). These diverse sequelae could be a result of intensified immune responses initially due to the copious production of proinflammatory cytokines: the so-called "cytokine storm syndrome", facilitating widespread oral and non-oral tissue damage. This review explores the interplay between HHV, SARS-CoV-2, and oral inflammatory diseases such as periodontitis, endodontic disease, and peri-implantitis. Additionally, the review discusses proper diagnostic techniques for identifying viral infection and how viral diagnostics can lead to improved overall patient health.

Increased Risk for Acute Periapical Abscesses in Multiple Sclerosis Patients and the Possible Association with Epstein-Barr Virus

INTRODUCTION

Multiple sclerosis (MS) is a severe inflammatory neuroimmune degenerative condition affecting more than 2 million individuals worldwide. The purpose of this study was to assess the prevalence of acute periapical abscesses in patients with MS and to evaluate whether acute periapical abscesses (PAs) are more likely to affect patients who were previously infected by Epstein-Barr virus (EBV).

METHODS

Integrated data of hospital patients were used. Data from the corresponding diagnosis codes for MS and acute PA were retrieved by querying the appropriate International Classification of Diseases, Tenth Revision codes in the database.

RESULTS

Of the total hospital patient population, 0.18% were diagnosed with a history of MS. Females were more affected than males 3.25-fold. Whites were more affected than African Americans 6-fold. Whites were more affected than African Americans combined with other ethnicities 3.6-fold. The odds ratio (OR) for acute PAs in patients with a history of MS was 2.2 (P < .0001). After adjustment for diabetes mellitus comorbidity, the OR for acute PAs in patients with a history of MS was 2.6. After adjustment for cardiovascular disease comorbidity, the OR for acute PAs in patients with a history of MS was 1.27. Of the patients who presented with PAs, 0.2% were diagnosed with a history of EBV infection. The OR was 3.98, and the difference in prevalence was statistically significant (P < .0001).

CONCLUSIONS

Under the conditions of this cross-sectional study, it appears that the prevalence of acute PAs is higher in patients with MS and that EBV may play a role.

Herpes Zoster and association with pulp necrosis and development of apical periodontitis - a review and presentation of two case reports

The varicella zoster virus as an aetiological agent for endodontic disease is not a well-recognised entity despite several published case reports. While advances in DNA molecular analysis techniques (PCR) have contributed to the current understanding of the potential role of the varicella zoster virus in the initiation and progression of endodontic disease, a review indicates a need for ongoing research. Case reports are presented of two female patients with a history of herpes zoster who developed pulp necrosis, with one patient progressing to apical periodontitis. Both patients received non-surgical endodontic therapy, followed by intra-coronal bleaching in one of the patients due to tooth discolouration which developed during the prodromal and acute phases of the herpes zoster infection. Clinical and radiographic examinations at 23 and 22 years, respectively, showed the affected teeth to be retained in an asymptomatic and aesthetically satisfactory state with no radiographic evidence of apical pathosis.

Acute periapical abscesses in patients with herpes simplex type 1 and herpes zoster

Aim: To assess the prevalence of acute periapical abscesses (PAs) in patients infected with herpes simplex type 1 (HS-1) and herpes zoster (HZ). Materials and methods: Integrated data of hospital patients was used. History of HS-1 and HZ diagnosis was retrieved by searching the appropriate query in the database. All cases were diagnosed for acute PAs by calibrated dentists in a hospital setting for patients admitted to urgent care. Diagnosis was made based on clinical examination and imaging data confirming the diagnosis of acute PAs without sinus tract. The odds ratio (OR) for the prevalence of acute PAs and its association with history of HS-1 and HZ were then calculated. Results: The prevalence of acute PAs in patients with a history HS-1 was 2.43% as compared to 0.59% in the general patient population of the hospital. The OR was 4.12 and the difference in prevalence was statistically significant (p < 0.0001). The prevalence of acute PAs in patients with a history HZ was 2.78% as compared to 0.59% in the general patient population of the hospital. The OR was 4.71 and the difference in prevalence was statistically significant (p < 0.0001). Conclusions: Under the conditions of this study, it appears that the prevalence of acute PAs is significantly higher in patients with a history of HS-1 and HZ infections and may warrant an antiviral therapy in certain resistant periapical abscesses.

Present status and future directions - microbiology of endodontic infections

Apical periodontitis has a microbial aetiology and is one of the most common inflammatory diseases that affect humans. Fungi, archaea and viruses have been found in association with apical periodontitis, but bacteria are by far the most prevalent and dominant microorganisms in endodontic infections. Bacterial infection of the root canal system only occurs when the pulp is necrotic or was removed for previous treatment. In some specific cases, including acute and chronic abscesses, the bacterial infection may reach the periradicular tissues. Intracanal bacteria are usually observed as sessile multispecies communities (biofilms) attached to the dentinal root canal walls. Infection in the main root canal lumen can spread to other areas of the root canal system. Although more than 500 bacterial species have been detected in endodontic infections, a selected group of 20 to 30 species are most frequently detected and may be considered as the core microbiome. There is a high interindividual variability in the endodontic microbiome in terms of species composition and relative abundance. Obligate anaerobic species are more abundant in the intraradicular bacterial communities of teeth with primary apical periodontitis, while both anaerobes and facultatives dominate the communities in post-treatment apical periodontitis. Bacterial interactions play an essential role in determining the overall virulence of the community, which has been regarded as the unit of pathogenicity of apical periodontitis. This article reviews the microbiologic aspects of endodontic infections and provides perspectives for future research and directions in the field.

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.

Valacyclovir in Pain Management of Acute Apical Abscesses: A Randomized Placebo-Controlled Double-Blind Pilot Study

INTRODUCTION

The acute (symptomatic) apical abscess is characterized by pulp necrosis, rapid onset, spontaneous pain, percussion pain, pus formation, and tissue swelling. The etiopathology of acute apical abscesses includes active (lytic) herpesviruses and gram-negative anaerobic bacteria. The present study examined the potential of valacyclovir, an anti-herpesvirus agent, and systemic amoxicillin to manage the pain of acute apical abscesses.

METHODS

Twenty emergency patients with moderate to severe apical abscess pain received randomly either amoxicillin (1 g immediate dose followed by 500 mg, 4 times a day, totally 7 days) + valacyclovir (2 g immediate dose followed by 500 mg, twice a day, totally 3 days) ("valacyclovir" group, 10 patients) OR amoxicillin (1 g immediate dose followed by 500 mg, 4 times a day, totally 7 days) + placebo ("placebo" group, 10 patients). Daily telephone calls during the 6-day follow-up period assessed pain level on a numeric rating scale and analgesic intake. The Mann-Whitney and the Friedman statistical tests analyzed the outcome data.

RESULTS

At the baseline examination, all 10 valacyclovir and 9 placebo patients exhibited moderate to severe pain and 18 patients needed pain medication. On the first day after baseline, the valacyclovir group showed 2 patients with moderate/severe pain and 1 patient on pain medication, but the placebo group revealed as many as 8 patients with moderate/severe pain and 9 patients on pain medication. The difference in pain level and analgesic usage between the valacyclovir and the placebo group remained statistically significant during the entire post-baseline study period (P < .05).

CONCLUSION

The present study points to valacyclovir as a promising adjunctive agent in pain control with acute apical abscesses.

Identification of microorganisms in irreversible pulpitis and primary endodontic infections with respect to clinical and radiographic findings

OBJECTIVES

The aim of this study was to evaluate the composition of microbiota of irreversible pulpitis and primary endodontic infections with respect to clinical and radiographic findings by performing cultures and 16s rDNA sequencing in Iranian patients.

MATERIAL AND METHODS

In this prospective cross-sectional study, samples were collected from 41 root canals for 4 main groups of patients. Bacterial identification was performed by the polymerase chain reaction (PCR) and 16s rDNA sequencing of aerobic and anaerobic cultivable colonies taken from patients' culture plates. Additionally, the presence of 13 bacterial species and 3 nonbacterial species was also explored using PCR and species-specific primers.

RESULTS

Sixteen microbial species, 1 fungus (Candida albicans), and 1 virus (Herpes simplex virus) were discovered and isolated. Species with the highest prevalence were Dialister invisus (68.3%), Porphyromonas gingivalis (58.8%), Streptococcus salivarius (58.5%), and Treponema denticola (56.1%). Lysinibacillus fusiformis (19.1%) was detected in the root canals for the first time. Candida albicans was seen in 11 cases (26.8%). Herpes simplex virus (HSV) was seen in 4 patients (9.8%).

CONCLUSIONS

Our results suggest that Gram-negative anaerobic oral bacteria are the majority of the microbes in primary endodontic infections. Various combinations of bacterial species were related to different clinical and radiographic conditions. Lysinibacillus fusiformis was detected for the first time in primary endodontic infections.

CLINICAL RELEVANCE

The results of this investigation might help clinicians choose to identify suspected endodontic pathogens in the etiology of each form of pulpal and periradicular diseases to determine the best therapeutic measures.

Herpesvirus-bacteria synergistic interaction in periodontitis

The etiopathogenesis of severe periodontitis includes herpesvirus-bacteria coinfection. This article evaluates the pathogenicity of herpesviruses (cytomegalovirus and Epstein-Barr virus) and periodontopathic bacteria (Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis) and coinfection of these infectious agents in the initiation and progression of periodontitis. Cytomegalovirus and A. actinomycetemcomitans/P. gingivalis exercise synergistic pathogenicity in the development of localized ("aggressive") juvenile periodontitis. Cytomegalovirus and Epstein-Barr virus are associated with P. gingivalis in adult types of periodontitis. Periodontal herpesviruses that enter the general circulation may also contribute to disease development in various organ systems. A 2-way interaction is likely to occur between periodontal herpesviruses and periodontopathic bacteria, with herpesviruses promoting bacterial upgrowth, and bacterial factors reactivating latent herpesviruses. Bacterial-induced gingivitis may facilitate herpesvirus colonization of the periodontium, and herpesvirus infections may impede the antibacterial host defense and alter periodontal cells to predispose for bacterial adherence and invasion. Herpesvirus-bacteria synergistic interactions, are likely to comprise an important pathogenic determinant of aggressive periodontitis. However, mechanistic investigations into the molecular and cellular interaction between periodontal herpesviruses and bacteria are still scarce. Herpesvirus-bacteria coinfection studies may yield significant new discoveries of pathogenic determinants, and drug and vaccine targets to minimize or prevent periodontitis and periodontitis-related systemic diseases.

Epstein-Barr virus reactivation by persistent apical periodontal pathogens

AIM

To assess whether Epstein-Barr virus (EBV) reactivation is triggered by persistent apical periodontitis-related microbes using in vitro and ex vivo methodologies.

METHODOLOGY

Surgically removed human periapical granulomas (n = 50) and healthy gingival tissues (n = 10) were analysed to determine the presence of EBV and seven persistent apical periodontitis-related microbes. In addition, real-time polymerase chain reaction was used to detect the mRNA expression of BZLF-1, an immediate-early gene of EBV. Expression of latent membrane protein (LMP)-1 and ZEBRA, an early lytic protein of EBV encoded by BZLF-1, was also examined using triple-colour immunofluorescence staining. n-Butyric acid produced by the microbes was quantified, and luciferase assays were performed in association with bacterial lysates. In addition, Daudi cells were cultured with bacterial lysates, and the expression levels of BZLF-1 mRNA and ZEBRA protein were determined.

RESULTS

EBV DNA and BZLF-1 mRNA were detected in 47 out of 50 periapical granulomas, but not in healthy gingival tissues. The EBV DNA copy number and the number of Fusobacterium nucleatum were significantly positively correlated with BZLF-1 expression in periapical granulomas. The number of Prevotella intermedia was slightly correlated with BZLF-1 expression; however, the other microbes were not. CD79a-positive B cells in periapical granulomas, but not those in healthy gingival tissues, expressed both LMP-1 and ZEBRA. n-Butyric acid production was the highest in F. nucleatum and the lowest in P. intermedia. Enterococcus faecalis, Candida albicans and the other tested microbes did not produce n-butyric acid. An F. nucleatum lysate exhibited significantly increased BZLF-1-luciferase activity in the same manner of commercial butyric acid, whereas P. intermedia did not. F. nucleatum also induced the expression of BZLF-1 mRNA and ZEBRA protein by Daudi cells, indicating that EBV reactivation was induced.

CONCLUSION

Among the persistent apical periodontitis-related bacteria that were tested, F. nucleatum most strongly reactivated latent EBV, whereas E. faecalis and C. albicans as well as the other microbes did not.

Herpesviruses and MicroRNAs: New Pathogenesis Factors in Oral Infection and Disease?

The oral cavity incessantly encounters a plethora of microorganisms. Effective and efficient oral innate and adaptive immune responses are incumbent to maintain healthy mucosa. A higher prevalence of Human Herpesviruses (HHV), a family of large enveloped DNA viruses, has been reported in multiple oral inflammatory diseases suggesting their involvement in disease progression. However, the viral components contributing to oral disease remain obscure. MicroRNAs (miRNA) are non-protein coding, single stranded ribonucleic acid (RNA) molecules that post-transcriptionally regulate diverse messenger RNAs. Thus, miRNAs can control large repertoire of biological processes. Changes in miRNA expression are associated with various oral infections and diseases. Cellular miRNAs can act as pro- or anti-viral factors and dysregulation of host miRNA expression occurs during herpesviruses infection. This strongly suggest a critical role of cellular miRNAs in host-herpesvirus interaction. Interestingly, HHV also encode multiple miRNAs (called viral miRNAs) that may play key role in host-pathogen interaction by modulating both host biological pathways and controlling viral life cycle. Recent studies from our laboratory have identified viral miRNAs (v-miRs) in diseased oral tissue biopsies and demonstrate their immunomodulatory roles. This review discusses the association of miRNAs (both host and viral) and herpesviruses in the pathogenesis of oral inflammatory diseases.

Herpesviral-bacterial co-infection in mandibular third molar pericoronitis

OBJECTIVE

The aim of this study was to assess the presence of herpesviruses and periodontopathic bacteria and to establish their potential association with pericoronitis.

MATERIALS AND METHODS

Fifty samples obtained with paper points (30 from pericoronitis and 20 controls) were subjected to polymerase chain reaction (PCR) analysis. A single-stage and nested PCR assays were used to detect herpesviruses: human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV) and six periodontopathic anaerobic bacteria: Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Parvimonas micra, Treponema denticola, and Tannarella forsythia.

RESULTS

Pericoronitis samples harbored HCMV and EBV at significantly higher rates than the control group (70 vs. 40 % and 46.7 vs. 15 %, P = 0.035, P = 0.021, respectively). P. micra and T. forsythia (66.7 vs. 0 %, and 40 vs. 10 %, P = 0.001, P = 0.021, respectively) were significantly more common in pericoronitis compared to the control group. Multivariate logistic regression analysis showed that the presence of T. forsythia was associated with pericoronitis development (OR 7.3, 95 % CI, 1.2-43.2, P = 0.028).

CONCLUSION

The occurrence of HCVM and EBV extends our previous knowledge on microbiota in pericoronitis. These PCR-based findings demonstrated that bacterial and viral DNA occurred concomitantly in pericoronitis samples. T. forsythia appeared to be significantly associated with pericoronitis development in the examined sample.

CLINICAL RELEVANCE

Herpesviral-bacterial co-infections might exacerbate the progression of pericoronitis.

Herpes zoster of gingiva in an older woman: a rare case report

OBJECTIVE

The aim of the article is to highlight the distinguishing features of secondary varicella gingival infection in an older women.

BACKGROUND

Herpes zoster is an acute sporadic, painful viral infection in older people caused by the reactivation of the latent varicella zoster virus. Herpes zoster affecting the gingiva without any dermal lesions is a rare pathological condition that mimics many intraoral vesiculobullous lesions. The ambiguous nature of this condition creates a diagnostic dilemma.

MATERIALS AND METHODS

A 58-year-old woman presented with an acute, unilateral and persistent burning sensation and pain in the gingiva with desqaumating vesicullobulous lesion.

RESULTS

The women was diagnosed with secondary varicella zoster infection.

CONCLUSION

Herpes zoster of the gingiva could manifest as painful desquamative vesicular lesions, pulpal or other painful neuralgic condition in older individuals which need careful diagnosis before formulating appropiate treatment plan.

A Familial Pattern of Multiple Idiopathic Cervical Root Resorption With a 30-Year Follow-Up

BACKGROUND

Multiple idiopathic cervical root resorption (MICRR) is a rare entity distinct from pathologic root resorption that occurs as a result of several local and systemic factors.

METHODS

This report describes a familial pattern of MICRR, including a recently identified case and a 30-year follow-up on previously described cases.

RESULTS

The previously reported father (aged 95 years) and son (aged 64 years), and the recently affected daughter (aged 61 years) recounted non-contributory medical history. The resorptive lesions were asymptomatic, unassociated with any predisposing factors, and first identified during the fourth to sixth decades of life. All tooth types were affected, with posterior teeth being affected earlier and with greater frequency; however, distal root surfaces were never affected. The resorptive lesions were progressive in nature, with additional teeth becoming involved as the condition was followed over time. In many instances, surrounding alveolar bone extended into the existing resorptive defects, but without clinical evidence of ankylosis. Gingival tissues, periodontal probing, and tooth mobility were within normal limits. Microcomputed tomography of extracted teeth demonstrated that the lesions were more extensive than clinically evident and rarely invaded the pulp chamber. Histologically, many resorptive lesions were noted along the cementum surface, with evidence of isolated cemental repair. Management of MICRR focused on restoring damaged root surfaces and extracting teeth with extensive root resorption.

CONCLUSIONS

MICRR is a challenging entity with unknown etiology and a lack of well-established preventive and management strategies. The familial pattern noted in this report necessitates future studies to investigate the role of genetic components in MICRR development.

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.

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.

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.

Multiple idiopathic cervical resorption: case report and discussion of management options

AIM

To present a case of cervical root resorption affecting all teeth and resulting in multiple tooth loss.

SUMMARY

A healthy 33-year-old Chinese male, with no contributory medical or family/social history, presented with generalized cervical root resorption. Lesions varied in severity amongst teeth and even involved an impacted third molar. All cervical root surfaces were affected and lesions often extended coronally, undermining enamel. CBCT demonstrated that the lesions were more extensive and more widely distributed than was seen using conventional radiography. Bone extended into many resorptive defects but without clinical evidence of ankylosis. Periodontal probing, pulp testing, percussion sound and mobility were within normal limits. Key learning points  • Aetiology of the generalized idiopathic cervical root resorption is uncertain. • Management is complex, and options have included surgical exposure and restoration of affected sites, extraction and submergence of affected roots. • A staged approach involving early intervention with restoration of resorptive defects, followed by progressive extraction and replacement with implant-supported prostheses is recommended.

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.

Nonsurgical root canal therapy of large cyst-like inflammatory periapical lesions and inflammatory apical cysts

It is a general belief that large cyst-like periapical lesions and apical true cysts caused by root canal infection are less likely to heal after nonsurgical root canal therapy. Nevertheless, there is no direct evidence to support this assumption. A large cyst-like periapical lesion or an apical true cyst is formed within an area of apical periodontitis and cannot form by itself. Therefore, both large cyst-like periapical lesions and apical true cysts are of inflammatory and not of neoplastic origin. Apical periodontitis lesions, regardless of whether they are granulomas, abscesses, or cysts, fail to heal after nonsurgical root canal therapy for the same reason, intraradicular and/or extraradicular infection. If the microbial etiology of large cyst-like periapical lesions and inflammatory apical true cysts in the root canal is removed by nonsurgical root canal therapy, the lesions might regress by the mechanism of apoptosis in a manner similar to the resolution of inflammatory apical pocket cysts. To achieve satisfactory periapical wound healing, surgical removal of an apical true cyst must include elimination of root canal infection.

Herpesviruses in abscesses and cellulitis of endodontic origin

Acute apical abscesses and cellulitis are severe endodontic diseases caused by opportunistic bacteria with possible coinfection with latent herpesviruses. The objectives of this study are to identify herpesviruses, including human cytomegalovirus (HCMV), Epstein-Barr virus (EBV), herpes simplex virus-1 (HSV-1), and Varicella zoster virus (VZV) in patients (n = 31) presenting with acute apical abscesses and cellulitis of endodontic origin. Primary and nested polymerase chain reaction (PCR) was conducted using virus-specific primers and DNA isolated from cell-free abscess fluid. From patients exhibiting concurrent spontaneous pain (n = 28), nine abscesses contained HCMV, two abscesses contained EBV, one abscess contained HSV-1, and no abscesses contained VZV. Control PCR using genomic or recombinant templates showed detection limits to a single genomic copy of HCMV, 100 genomic copies for EBV, and 1 to 10 copies for HSV-1 with no cross-amplification between herpesviral DNA targets. Nested PCR was required for detection of herpesviral DNA in the abscess specimens, indicating that these viruses were present in low copy number. Filtration of abscess specimens and virus transfer experiments using human fibroblastic MRC-5 cells confirmed the presence of HCMV particles in several abscess specimens. We conclude that herpesviruses are present but not required for the development of acute apical abscesses and cellulitis of endodontic origin.

T lymphocyte activation and cytokine expression in periapical granulomas and radicular cysts

INTRODUCTION

Radicular cysts (RCs) are periapical lesions resulting in jaw bone destruction. The inflammatory dental periapical granuloma (PG) is considered to be the origin of RC formation; however the mechanism of RC development remains unclear.

METHODS

Cell suspension from the surgically extirpated tissue of 27 RCs and 25 PGs was obtained. Bacteriological analysis of the PG tissue samples was performed in order to define two major groups of PG according to the prevailing causative bacterial infection: the streptococcal PG (PG-S, n=10) and the anaerobe PG (PG-A, n=9) group. The inflammatory response of tissue infiltrating lymphocytes was assessed by following T lymphocyte activation (HLA-DR expression) as well as interferon gamma (IFN-gamma) and interleukin 4 (IL-4) production which were evaluated by the flow cytometry.

RESULTS

In comparison to RC both types of PG contained a higher proportion of activated T cells (HLA-DR) and lower proportion of IL-4 producing cells. PG-A tissue contained increased percentage of CD3 cells and increased percentage of T helper 1 (Th1) cells in comparison with PG-S. In RC the IFN-gamma production is higher than in streptococcal PG-S but similar as in PG-A.

DISCUSSION

Tissue infiltration by Th2 cells and IL-4 production is likely to play an etiopathogenic role in RC formation.

Herpesviruses in endodontic pathoses: association of Epstein-Barr virus with irreversible pulpitis and apical periodontitis

Irreversible pulpitis and apical periodontitis are inflammatory diseases caused by opportunistic bacteria with possible co-infection with latent herpesviruses. The objectives of this study are to identify herpesviruses, including human cytomegalovirus (HCMV), Epstein-Barr virus (EBV), herpes simplex virus (HSV-1), and Varicella zoster virus (VZV) in patients with irreversible pulpitis (n = 29) or apical periodontitis, either primary (n = 30) or previously treated (n = 23). Using primary and nested polymerase chain reaction (PCR) and reverse transcription-PCR, EBV DNA and RNA were present in endodontic pathoses in significantly higher percentages (43.9% and 25.6%, respectively) compared with healthy pulp controls (0% and 0%, respectively). HCMV DNA and RNA were found in measurable numbers in both endodontic patients (15.9% and 29.3%, respectively) and in healthy pulp controls (42.1% and 10.5%, respectively). HSV-1 DNA was found in low percentages in endodontic patients (13.4%), and only one patient showed the presence of VZV. In conclusion, EBV may be associated with irreversible pulpitis and apical periodontitis.

Herpesviruses in asymptomatic apical periodontitis lesions: an immunohistochemical approach

INTRODUCTION

Human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV) have been recently detected in samples from apical periodontitis lesions by means of molecular biology techniques and a role in the pathogenesis of this disease has been suggested. The present study was designed to survey asymptomatic primary apical periodontitis lesions for the presence of HCMV- and/or EBV-infected cells by means of immunohistochemistry.

METHODS

Apical periodontitis lesions were obtained from 35 patients [26 human immunodeficiency virus (HIV) -seronegative patients and nine HIV-seropositive patients] after tooth extraction and subjected to immunohistochemical analysis using monoclonal antibodies specific for HCMV and EBV.

RESULTS

Fifteen of the 35 apical periodontitis lesions were positive for the target herpesviruses. Overall, EBV was found in 31% of the samples and HCMV in 23%, with 14% of the lesions showing EBV and HCMV dual infection. No association was found between HCMV or EBV with any particular histopathological type of apical periodontitis (P > 0.05). HCMV was significantly more frequent in apical periodontitis lesions from HIV-positive patients (67%) than in lesions from HIV-negative patients (8%) (P = 0.001). EBV was detected in 44% of lesions from HIV-positive patients and in 27% of lesions from HIV-negative patients, but this difference was not significant (P = 0.91).

CONCLUSION

Our results showed that cells infected by HCMV and EBV can be found in apical periodontitis lesions, with a higher prevalence in HIV-positive patients. The specific role that these viruses play in the pathogenesis of apical periodontitis remains to be described.

Epstein-Barr virus in oral diseases

Epstein-Barr virus (EBV), a B-lymphotropic gamma-herpesvirus, causes infectious mononucleosis and oral hairy leukoplakia, and is associated with various types of lymphoid and epithelial malignancies. Saliva is the main vehicle for EBV transmission from individual to individual. Recent studies have also implicated EBV in the pathogenesis of advanced types of periodontal disease. EBV DNA is detected in 60-80% of aggressive periodontitis lesions and in 15-20% of gingivitis lesions or normal periodontal sites. The periodontal presence of EBV is associated with an elevated occurrence of periodontopathic anaerobic bacteria. Moreover, EBV active infection occurs in approximately 70% of symptomatic and large-size periapical lesions. EBV and cytomegalovirus often co-exist in marginal and apical periodontitis. Periodontal therapy can markedly suppress the EBV load in periodontal pockets as well as in saliva, which has the potential to reduce the risk of viral transmission between close individuals. EBV proteins up-regulate cytokines and growth factors, which seem to play a central role in the proliferative response of tongue epithelial cells in oral hairy leukoplakia and in the cell-transformation process of EBV-associated malignancies. Further research is needed to identify the full range of EBV-related diseases in the human oral cavity.

Echographic evaluation of bone lesions of endodontic origin: report of two cases in the same patient

We report on two periapical lesions of endodontic origin detected in the maxillary bone of the same patient, whose echographic examination was used to address a tentative differential diagnosis between a granuloma and a cystic lesion. The patient on whom two periapical lesions were diagnosed with clinical and conventional radiographic findings and scheduled for endodontic surgery, was also examined using echography and color power doppler at the site of the lesions. The lesions were echographically described in each case according to a scheme from a previous work. A tentative differential diagnosis between a cystic lesion and a granuloma was made. One lesion was described as a cyst, the other as a granuloma. After surgical excision, the lesions were examined under light microscopy. In both cases the two echographic diagnoses were confirmed by the histopathologic examination.

On the causes of persistent apical periodontitis: a review

Apical periodontitis is a chronic inflammatory disorder of periradicular tissues caused by aetiological agents of endodontic origin. Persistent apical periodontitis occurs when root canal treatment of apical periodontitis has not adequately eliminated intraradicular infection. Problems that lead to persistent apical periodontitis include: inadequate aseptic control, poor access cavity design, missed canals, inadequate instrumentation, debridement and leaking temporary or permanent restorations. Even when the most stringent procedures are followed, apical periodontitis may still persist as asymptomatic radiolucencies, because of the complexity of the root canal system formed by the main and accessory canals, their ramifications and anastomoses where residual infection can persist. Further, there are extraradicular factors -- located within the inflamed periapical tissue -- that can interfere with post-treatment healing of apical periodontitis. The causes of apical periodontitis persisting after root canal treatment have not been well characterized. During the 1990s, a series of investigations have shown that there are six biological factors that lead to asymptomatic radiolucencies persisting after root canal treatment. These are: (i) intraradicular infection persisting in the complex apical root canal system; (ii) extraradicular infection, generally in the form of periapical actinomycosis; (iii) extruded root canal filling or other exogenous materials that cause a foreign body reaction; (iv) accumulation of endogenous cholesterol crystals that irritate periapical tissues; (v) true cystic lesions, and (vi) scar tissue healing of the lesion. This article provides a comprehensive overview of the causative factors of non-resolving periapical lesions that are seen as asymptomatic radiolucencies post-treatment.

Exploiting Molecular Methods to Explore Endodontic Infections: Part 2—Redefining the Endodontic Microbiota

The second part of this review discusses the application of molecular methods in endodontic microbiology research for a comprehensive characterization of the microbiota associated with different types of endodontic infections. Despite their recent introduction in endodontic research, molecular methods have already given a significant contribution to the understanding of endodontic infections and the future holds the perspective of a still better refinement of the knowledge about these infections. Molecular methods have revealed a higher complexity of the endodontic microbiota than previously reported by cultivation approaches. In addition to detecting some cultivable species in increased prevalence, molecular methods have also expanded the list of putative endodontic pathogens by inclusion of some fastidious bacterial species or even uncultivated bacteria that have never been previously found in endodontic infections.