Prevalence of unculturable bacteria in the periapical abscess: A systematic review and meta-analysis

Bacterial genera in the fluids from apical periodontitis-related radicular cysts: An observational study

AIM

This study aimed to evaluate bacteriome profiles (diversity, composition and relative abundances of bacterial genera) of the fluids from apical periodontitis (AP)-related radicular cysts (RCs).

METHODOLOGY

This observational study included 29 patients with AP and RC with complete sample triplets (supragingival plaque, cryopulverized tooth and cystic fluid). The bacteriome profiles of each matrix as well as of negative controls (NCs) were examined using 16S rRNA amplicon sequencing.

RESULTS

Bacteriome profiles of cystic fluids differed from NCs in 79% of cases. The number of distinct amplicon sequence variants and Shannon index detected in cystic fluids and cryopulverized teeth were significantly lower than in paired supragingival plaque samples. Gram-negative genera and anaerobic genera were more abundant in cystic fluids than in paired cryopulverized teeth or their supragingival plaques. The relative abundances of the genera Prevotella_7/Prevotella, Fusobacterium and Porphyromonas were higher in cystic fluids than in paired cryopulverized teeth and NCs; their relative abundances dominated (>20%) in individual cystic fluids. Also, DNA from the genus Fretibacterium was significantly more commonly found in cryopulverized teeth and cystic fluids than in supragingival plaque samples. The relative abundances of this gram-negative bacterial genera in cryopulverized teeth differed from NCs; the difference from cystic fluids was borderline insignificant.

CONCLUSIONS

Although the alpha-diversity in the cystic fluids is much lower compared to supragingival plaques, most cystic fluids are not sterile. DNA from specific anaerobic gram-negative bacterial genera dominated the fluids from AP-related RCs.

Viable but non-cultivable state in oral microbiota: a critical review of an underexplored microbial survival strategy

The viable but non-cultivable (VBNC) state and persister cells, two dormancy phenomena in bacteria, differ in various aspects. The entry of bacteria into the VBNC state as a survival strategy under stressful conditions has gained increasing attention in recent years, largely due to the higher tolerance of VBNC cells to antibiotics and antimicrobials resulting from their low metabolic activity. The oral cavity favors biofilm growth in dental hard tissues, resulting in tooth decay and periodontitis. Despite advances in VBNC state detection in the food industry and environment, the entry capability of oral bacteria into the VBNC state remains poorly documented. Furthermore, the VBNC state has recently been observed in oral pathogens, including Porphyromonas gingivalis, which shows potential relevance in chronic systemic infections, Enterococcus faecalis, an important taxon in endodontic infections, and Helicobacter pylori, which exhibits transient presence in the oral cavity. Further research could create opportunities to develop novel therapeutic strategies to control oral pathogens. The inability of conventional culture-based methods to identify VBNC bacteria and the metabolic reactivation of dormant cells to restore susceptibility to therapies highlights a notable gap in anti-VBNC state strategies. The lack of targeted approaches tested for efficacy against VBNC bacteria underscores the need to develop novel detection methods. This review discusses the VBNC state, its importance in public health, and diagnostic techniques, with a special focus on the VBNC state in oral bacteria.

Fractal Dimension Approach for Quantitative Analysis Radiograph in Periapical Inflammation: A Systematic Review

Background and Objective

Periapical inflammation on visual interpretation, especially in conditions of early inflammation, is very dependent on visual acuity. Visual ability can only detect if the inflammatory condition in the periapical area is more than 30%. This study reviewed the use of fractal dimension (FD) for quantitative assessment radiographs in periapical inflammation.

Methods

The search was performed using PubMed, Web of Science, and Scopus databases. The inclusion criteria were clinical research, the area was in the periapical inflammation, used the periapical radiograph, measured the fractal dimension in human bone, the article studies were in the English language. There was no restriction for publication date.

Results

Five articles were found in which fractal dimension was applied for the assessment of periapical lesions visually indiscernible in radiographs, for evaluation of apical inflammation, for imaging diagnosis of the periapical lesion, for analysis of trabecular bone, and for analysis of trabecular bone structure around the bone of periapical inflammation. Various sizes and sites of the regions of interest were used to evaluate the bone structure of periapical inflammation with fractal dimension.

Conclusion

Fractal dimension in Dentistry has been widely applied to the study of images. Periapical radiographs were the most frequently used. The Image J software and the fractal analysis method were extensively adopted in the studies reviewed herein. Further studies are encouraged to improve the use of fractal dimension in assessing quantitative radiographs in periapical inflammation.

Exploring Relationships Between Circulating Interleukins and Pulp and Periapical Diseases: A Bidirectional Mendelian Randomization Study

INTRODUCTION

The aim of this study was to comprehensively evaluate the links of genetic predisposition among 13 common circulating interleukins (ILs) and endodontic diseases by using a 2-sample Mendelian randomization method.

METHODS

Single nucleotide polymorphisms were chosen as instrumental variables from summary data of genome-wide association studies (GWASs), using the inverse-variance-weighted method as the primary analysis. In addition, a variety of sensitivity analyses was conducted to evaluate the resilience of the primary outcomes and identify any inherent pleiotropic effects.

RESULTS

After multiple comparison corrections, 4 circulating ILs were genetically predicted to significantly play a role in endodontic diseases. Among these, circulating IL-17 (odds ratio [OR]IVW, 1.33; 95% confidence interval [CI], 1.15-1.54; P < 3.85 × 10-3) were significantly identified as potential risk-increasing factors toward pulp and periapical diseases, and circulating IL-16 (ORIVW, 0.89; 95% CI, 0.83 to 0.94; P < 3.85 × 10-3) may exert protective effects on the development of periapical abscess. In the reverse analyses, null significantly association was found between genetic liability to endodontics disorders and the corresponding circulating inflammatory biomarkers. Overall, sensitivity analyses were consistent with the estimates direction of primary analyses results, supporting the reliability of findings.

CONCLUSIONS

Given the unavoidable limitations presented in this study, our findings provided significant evidence to support the identification of elevated IL-16 levels as a potential risk-mitigating factor, whereas elevated IL-17 levels exhibit potentially deleterious effects on endodontic disorders. Future validation is warranted to examine the conclusions of our study and to evaluate the potential application of these circulating ILs as lifestyle or pharmacological targets for oral health care.

Causal relationship, shared genes between rheumatoid arthritis and pulp and periapical disease: evidence from GWAS and transcriptome data

Objective

Patients with rheumatoid arthritis (RA) have an increased risk of developing pulp and periapical disease (PAP), but the causal relationship and shared genetic factors between these conditions have not been explored. This study aimed to investigate the bidirectional causal relationship between RA and PAP and to analyze shared genes and pathogenic pathways.

Methods

We utilized GWAS data from the IEU Open GWAS Project and employed five Mendelian randomization methods (MR Egger, weighted median, inverse variance weighted, simple mode, and weighted mode) to investigate the bidirectional causal relationship between RA and PAP. Transcriptome data for RA and irreversible pulpitis (IRP) were obtained from the GEO database. Hub genes were identified through differential analysis, CytoHubba, machine learning (ML), and other methods. The immune infiltration of both diseases was analyzed using the ssGSEA method. Finally, we constructed a regulatory network for miRNAs, transcription factors, chemicals, diseases, and RNA-binding proteins based on the identified hub genes.

Results

RA was significantly associated with an increased risk of PAP (OR = 1.1284, 95% CI 1.0674-1.1929, p < 0.001). However, there was insufficient evidence to support the hypothesis that PAP increased the risk of RA. Integrating datasets and differential analysis identified 84 shared genes primarily involved in immune and inflammatory pathways, including the IL-17 signaling pathway, Th17 cell differentiation, and TNF signaling pathway. Using CytoHubba and three ML methods, we identified three hub genes (HLA-DRA, ITGAX, and PTPRC) that are significantly correlated and valuable for diagnosing RA and IRP. We then constructed a comprehensive regulatory network using the miRDB, miRWalk, ChipBase, hTFtarget, CTD, MalaCards, DisGeNET, and ENCORI databases.

Conclusion

RA may increase the risk of PAP. The three key genes, HLA-DRA, ITGAX, and PTPRC, have significant diagnostic value for both RA and IRP.

COVID-19 Severity in Patients With Apical Periodontitis: A Case Control Study

OBJECTIVES

Apical periodontitis (AP) has been associated with systemic inflammatory biomarkers that have also been associated with COVID-19 severity. This study was designed to test the hypothesis that the presence of apical periodontitis could be associated with increased risk of COVID-19 complications.

METHODS

A case control study (N = 949) was performed using the medical and dental records of patients diagnosed with COVID-19 in the State of Qatar between March 2020 and February 2021. Cases comprised COVID-19 patients (n = 63) who experienced complications (death, intensive care unit admissions, mechanical ventilation), and controls were COVID-19 patients (n = 886) who recovered without such complications. The presence of periapical apical periodontitis was assessed on the radiographic records taken prior to COVID-19 infection. Associations between apical periodontitis and COVID 19 complications were analysed using logistic regression models adjusted for demographic and medical factors. Blood biomarkers were assessed in both groups and compared using the Kruskal-Wallis test.

RESULTS

COVID-19 complications were found to be associated with the presence of apical periodontitis (adjusted odds ratio = 2.72; 95% CI, 1.30-5.68; P = .008). Blood analyses revealed that COVID-19 patients with apical periodontitis had higher levels of white blood cells and haemoglobin A1c than the patients without apical periodontitis.

CONCLUSIONS

The presence of apical periodontitis could be associated with increased risk of COVID-19 complications.

Negative pressure pulmonary edema following laryngospasm after dental abscess: A case report

Negative pressure pulmonary edema (NPPE), also known as post-obstructive pulmonary edema, is a rare and life-threatening condition. It occurs when a person breathes against an obstructed glottis, causing negative thoracic pressure in the lungs. This negative pressure can lead to fluid accumulation in the lungs, resulting in pulmonary edema. The obstructed glottis might be caused by laryngospasm, which occurs when the muscles around the larynx involuntarily spasm and can lead to complete upper airway occlusion. This report shares the case of a 33-year-old woman hospitalized for periapical dental abscess, facial swelling, and shortness of breath. The patient exhibited signs of poor oral hygiene. After the exacerbation of her symptoms, she showed signs of asphyxia and decreased oxygen saturation, which led to her intubation. Imaging revealed bilateral pleural effusion and patchy ground glass opacities favoring NPPE. After three days of treatment with diuretics and other conservative measures, her condition was alleviated, and she was extubated. Laryngospasm in the presence of a dental abscess is uncommon. Identification of imaging favoring NPPE in this setting is even more rare. In cases of laryngospasm, prompt intubation is crucial. Therapy with diuretics and other conservative measures can effectively treat NPPE following laryngospasm.

Viable but nonculturable (VBNC) state, an underestimated and controversial microbial survival strategy

As a unique microbial response to adverse circumstances, the viable but nonculturable (VBNC) state is characterized by the loss of culturability of microbial cells on/in nutrient media that normally support their growth, while maintaining metabolic activity. These cells can resuscitate to a culturable state under suitable conditions. Given the intrinsic importance of the VBNC state and recent debates surrounding it, there is a need to redefine and standardize the term, and to address essential questions such as 'How to differentiate VBNC from other similar terms?' and 'How can VBNC cells be standardly and accurately determined?'. This opinion piece aims at contributing to an improved understanding of the VBNC state and promoting its proper handling as an underestimated and controversial microbial survival strategy.

Microbiological Aspects Concerning the Etiology of Acute Odontogenic Inflammatory Diseases in the Soft Tissues of the Head and Neck Region

Odontogenic purulent inflammatory diseases (OPID) make up about 20% of cases in the structure of general surgical pathology and are among the frequent diseases of the maxillofacial region (MFR) with a high (10-40%) mortality rate. Insufficient information about the source state of acute odontogenic inflammation of the peri-mandibular soft tissues significantly reduces the effectiveness of diagnostic measures of OPID in MFR, as evidenced by almost 50% of the diagnostic error rate. Statistically, OPID in soft-tissue of MFR most often occur due to dissemination of pathogens of the necrotized pulp, periodontal pockets in periodontitis or pericoronitis during the difficult eruption of retained teeth. Previously, the quantitative dominance (about 70%) of Staphylococcus spp. among the microorganisms isolated from the odontogenic foci of inflammation was determined. However, in recent years, with the expansion of microbiological diagnostic capabilities, the presence of non-fermenting Gram-negative bacteria and anaerobes with a significant proportional proportion of the total microbiota of OPID in soft tissue of MFR has been increasingly indicated. Recently, there has been a rapid acquisition of resistance of pathogens of odontogenic purulent inflammatory diseases of the maxillofacial region to various groups of antibiotics, which leads to ineffectiveness of their treatment and prompts the revision of existing protocols and treatment regimens in surgical dentistry