Influence of irrigation and laser assisted root canal disinfection protocols on dislocation resistance of a bioceramic sealer.

BACKGROUND: It is not yet clear how different irrigation protocols and intracanal laser irradiation effects bioceramic sealers. In this vitro study, we aimed to evaluate the dislocation resistance of a bioceramic root canal sealer after different laser-assisted disinfection protocols and irrigants. METHODS: Sixty extracted human straight single-canal teeth were instrumented, and randomly divided into five experimental groups (n=10) according to the disinfection protocol used: group 1, conventional needle irrigation (CI) with sodium hypochlorite (NaOCl)+ethylenediaminotetraacetic acid (EDTA)+NaOCl; group 2, Photon initiated photoacoustic streaming (PIPS) of NaOCl+EDTA+NaOCl; group 3, NaOCl+EDTA+diode laser; group 4, NaOCl+EDTA+photodynamic therapy (PDT); group 5, CI with NaOCl+EDTA+Chlorhexidine (CHX); and control group without any treatment. The root canals were filled with a bioceramic root canal sealer (BioRoot RCS) using the single-cone filling technique. After three weeks of storage, the samples from each canal thirds were transversely sectioned and the push-out test was performed. RESULTS: The PIPS group showed the lowest dislocation resistance values in the coronal third (p>0.05), and no difference was observed among the other groups (p<0.05). The dislocation resistance in the middle and apical thirds was the highest in the diode laser group (p<0.05). CONCLUSION: Final root canal irradiation with diode laser led to improved dislocation resistance of the bioceramic sealer. PDT did not adversely affect the dislocation resistance of BioRoot RCS. The PIPS reduced the dislocation resistance values in the coronal third, but not in the middle and apical thirds.

Prevalence of Apical Periodontitis and Conventional Nonsurgical Root Canal Treatment in General Adult Population: An Updated Systematic Review and Meta-analysis of Cross-sectional Studies Published between 2012 and 2020.

INTRODUCTION: This study aimed to summarize data on apical periodontitis (AP) and nonsurgical root canal treatment (NSRCT) prevalence and risk factors related to age, gender, and quality of restorative and endodontic treatment in the general population from cross-sectional studies published between 2012 and 2020. METHODS: An electronic search was performed in the following databases: Web of Science, Scopus, and PubMed. The conducted literature search covered studies published between 2012 and 2020, without restrictions on language. The STROBE and NOS tools were used for quality assessment of the included studies. RESULTS: Sixteen articles were included in the review. In total, 200,041 teeth were examined. On average, 6.3% of teeth had AP, and 7.4% had NSRCT. Forty-one percent of RCT teeth had AP, and 3.5% of untreated teeth had AP. Female patients were less prone to AP in endodontically treated teeth only, compared with male patients (P < .001). Variable stratification of age subgroups among included studies prevented us from conducting a meta-analysis. An increase in AP frequency was found in teeth with inadequate restorative and endodontic treatment (P < .001 and P < .001, respectively). Because of high heterogeneity, these results should be taken with caution. CONCLUSIONS: There is an increased AP prevalence in the adult general population compared with data from 2012 (6.3% versus 5.4%) in both endodontically treated (41.3% versus 35.9%) and untreated teeth (3.5% versus 2.1%). In addition, AP developed less frequently in female patients with endodontically treated teeth and in teeth with inadequate compared with adequate restorative and endodontic treatment.

Notch - a possible mediator between Epstein-Barr virus infection and bone resorption in apical periodontitis.

Objectives: This study aimed to investigate whether Epstein-Barr virus (EBV) positive periapical lesions exhibited higher mRNA levels of Notch signalling molecules (Notch2 and Jagged1), bone resorption regulators (receptor activator of nuclear factor kappa-ß ligand (RANKL) and osteoprotegerin (OPG)), and proinflammatory cytokines (tumour necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1ß) and IL-6) compared to EBV negative lesions. Additionally, the potential correlation between investigated molecules in periapical lesions was analyzed.Materials and methods: Sixty-four apical periodontitis lesions were obtained subsequent to standard apicoectomy procedure. The presence of EBV was determined using nested PCR. Based on the presence of EBV all periapical lesions were divided into two groups, 29 EBV positive and 35 EBV negative lesions. A reverse transcriptase real-time PCR was used to determine mRNA levels of Notch2, Jagged1, RANKL, OPG, TNF-α, IL-1ß and IL-6.Results: Significantly higher mRNA levels of Notch2, Jagged1, RANKL and IL-1ß were observed in EBV positive compared to EBV negative lesions. Significant positive correlation was present between Notch2 and Jagged1, Jagged1 and RANKL, and IL-ß and TNF-α in EBV positive periapical lesions.Conclusions: Notch signalling pathway may be involved in alveolar bone resorption in apical periodontitis lesions infected by EBV.

Notch signaling pathway mediates alveolar bone resorption in apical periodontitis.

Apical periodontitis represents a chronic inflammatory process within periapical tissues, mostly caused by etiological agents of endodontic origin. Progressive bone resorption in the periapical region represents the hallmark of apical periodontitis and occurs as the consequence of interplay between polymicrobial infections and host response. The Notch signaling pathway is an evolutionary conserved cell-signaling system that plays an important role in a variety of cell functions including proliferation, differentiation and apoptosis. In recent years its involvement in bone homeostasis has attracted a significant consideration. We hypothesized that Notch signaling pathway, which has a complex interplay with proinflammatory cytokines and bone resorption regulators, contributes to alveolar bone resorption via increased Notch receptors on immune cell surface and stimulates Notch receptor intracellular domain (NICD) translocation into the nucleus. The potential benefit of medications aimed to down-regulate these pathways in apical periodontitis treatment remains to be assessed.

Notch Signaling Pathway in Apical Periodontitis: Correlation with Bone Resorption Regulators and Proinflammatory Cytokines.

INTRODUCTION: The exact mechanisms of periapical bone resorption have not been fully elucidated. This study aimed to analyze the expression of Notch signaling molecules (Notch2, Jagged1, and Hey1) and proinflammatory cytokines (tumor necrosis factor alpha [TNF-α], interleukin [IL]-1ß, and IL-6) in human apical periodontitis lesions with different receptor activator of nuclear factor kappa B ligand (RANKL)/osteoprotegerin (OPG) ratios and determine their potential correlation. METHODS: The study group consisted of 50 periapical lesions collected in conjunction with apicoectomy. The relative gene expression of the investigated molecules (Notch2, Jagged1, Hey1, RANKL, OPG, TNF-α, IL-1ß, and IL-6) in all tissue samples was analyzed using reverse transcriptase real-time polymerase chain reaction. The Student t test, Mann-Whitney U test, and Spearman correlation were used for statistical analysis. RESULTS: Based on the RANKL/OPG ratio, periapical lesions were either RANKL predominant (RANKL > OPG, n = 33) or OPG predominant (RANKL < OPG, n = 17). Symptomatic lesions occurred more frequently in RANKL-predominant compared with OPG-predominant lesions (24 vs 7, P = .029). Notch2, Jagged1, Hey1, and TNF-α were significantly overexpressed in lesions with predominant RANKL compared with lesions with predominant OPG (P = .001, P = .001, P = .027, and P = .016, respectively). Significant correlations were observed between the investigated genes in periapical lesions. CONCLUSIONS: Notch signaling appeared to be activated in periapical inflammation. An increase in Notch2, Jagged1, Hey1, and TNF-α expression in RANKL-predominant periapical lesions corroborates their joined involvement in extensive periapical bone resorption.

The Role of Varicella Zoster Virus in the Development of Periapical Pathoses and Root Resorption: A Systematic Review.

INTRODUCTION: Varicella zoster virus (VZV) and subsequent herpes zoster (HZ) infection have been proposed as a causative agent of periapical pathoses and root resorption. This review aimed to identify, synthesize, and present a critical analysis of the available data on the association among VZV, subsequent HZ infection, and the development of periapical pathoses and root resorption and to analyze the level of evidence of available studies. METHODS: The literature search covered MEDLINE, Science Citation Index Expanded, and Scopus. A qualitative critical appraisal of the included articles was performed. RESULTS: The electronic database search yielded 66 hits from PubMed, 73 hits from Web of Science, and 107 from Scopus. Seven case reports and 3 cross-sectional studies were included in the final review. When summarized, in 7 patients with a history of a previous HZ attack and with no other apparent cause, 23 teeth were diagnosed with apical periodontitis, 8 teeth with internal and 1 tooth with external root resorption. The cross-sectional studies investigated the presence of VZV DNA in samples of acute apical abscess. The VZV DNA was found only in 2 of 65 samples. CONCLUSIONS: All studies included in this systematic review had a low level of evidence (4 and 5). Still, the potential role of VZV in the etiopathogenesis of periapical pathoses and root resorption cannot be ruled out. Future investigations should be directed toward the analysis of VZV pathologic effects on pulp blood vessels, which might cause local ischemia and tissue necrosis.

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.

Epstein-Barr virus infection induces bone resorption in apical periodontitis via increased production of reactive oxygen species.

Chronic inflammatory processes in periapical tissues caused by etiological agents of endodontic origin lead to apical periodontitis. Apart from bacteria, two herpesviruses, Epstein-Barr virus (EBV) and Human cytomegalovirus (HCMV) are recognized as putative pathogens in apical periodontitis. Although previous reports suggest the involvement of EBV in the pathogenesis of apical periodontitis, its exact role in periapical bone resorption has not yet been fully elucidated. We hypothesize that EBV infection in apical periodontitis is capable of inducing periapical bone resorption via stimulation of reactive oxygen species (ROS) overproduction. Increased levels of ROS induce expression of receptor activator of nuclear factor kappa B (NF-κB) ligand (RANKL). RANKL binding to receptor activator of nuclear factor κB (RANK) present on the surface of preosteoclasts induces their maturation and activation which consequently leads to bone resorption. The potential benefit of antiviral and antioxidant-based therapies in periapical bone resorption treatment remains to be assessed.

[Morphological characteristics of mesiobuccal root canals of the first maxillary molars].

INTRODUCTION: The first maxillary molar is a tooth with three roots, and mesiobuccal one is with the most complex canal morphology. Factors influencing variations of its morphology are numerous, and may significantly complicate endodontic treatment. OBJECTIVE: The objective was to investigate the number, configuration and curvature orientation of the mesiobuccal root canals in the maxillary first molars. METHODS: The study was conducted on 200 mesiobuccal (MB) roots of extracted first molars in human subjects using radiography. In each canal Flexofile was introduced until reaching the apical foramen and the root was then radiographed in series from two projections. Number of root canals (MB1, MB2 and MB3), configuration according to Vertucci classification, and the orientation of the curvature were established. Relevant statistical parameters and the significance of differences were computed (p < 0.05). RESULTS: Of total 200 mesiobuccal roots 86.5% were with two, 9% with three, and 4.5% with a single canal. Most frequent configurations were type IV (36%) and II (34.5%). From the clinical projection all MB, canals were oriented distally, from the proximal 78% palatally and 22% buccally. The orientation of all MB2 canals was distal from the clinical projection, from the proximal projection 76% were oriented palatally, and 24% buccally. The MB3 canal was always oriented distally from the clinical projection, and buccally from the proximal aspect. CONCLUSION: The mesiobuccal roots of the first maxillary molars showed multiple canals in 96%, with dominant Vertucci type II and IV of configuration. All canals were curved.