Genetic predisposition to persistent apical periodontitis

Healing of apical periodontitis in type II diabetes mellitus patients: A prospective study

OBJECTIVE

This study aimed to compare the healing of periapical bone between type II diabetes patients and healthy patients after root canal treatment.

SUBJECTS AND METHODS

This study included 26 diabetic patients and the control group with healthy patients matching the diabetic group in age and sex. The study included only teeth with satisfactory coronal restoration. The periapical index system was used to evaluate the periapical status of treated teeth at follow-ups after 6 and 12 months.

RESULTS

Analysis of the results revealed a significantly higher healing rate in the control group compared to the diabetic group only at the 6-month follow-up (66.6 vs. 33.3%; Χ2 = 4.857; p = 0.0275). Analysis of the full-scale PAI index disclosed significantly higher PAI values in the diabetic subjects at 6- and 12-month follow-up. The regression analysis showed that the risk of apical periodontitis persistence increased significantly with female gender (OR = 3.92; 95% CI = 1.04-14.79; p = 0.043), diabetes mellitus (OR = 4.27; 95% CI: 1.18-15.50; p = 0.027) and higher household income (OR = 5.39; 95% CI = 1.33-21.89; p = 0.018).

CONCLUSION

Root canal treatment remains an effective means of conservative treatment in diabetic patients. While the healing is not compromised, regular follow-ups are necessary to monitor the healing process.

Effects of melatonin against experimentally induced apical periodontitis in rats

Apical periodontitis is an inflammatory condition resulting from microbial invasion in the root canal system, causing periapical tissue destruction and bone resorption. This study investigated melatonin's effects, known for its antioxidant and anti-inflammatory properties, on experimentally induced apical periodontitis in rats. Three groups of rats were studied: control, apical periodontitis and apical periodontitis with melatonin treatment. Proinflammatory cytokines and enzyme levels in blood serum were measured, and micro-CT analysis assessed bone resorption. Results showed significantly elevated cytokines and enzyme levels in the apical periodontitis group compared to the control. However, in the melatonin-treated group, these levels were significantly reduced (p < 0.01-0.001). Micro-CT analysis indicated decreased periapical resorption cavity volume and surface area with melatonin treatment. This suggests that systemic melatonin administration can mitigate inflammation and reduce bone resorption in experimentally induced apical periodontitis in rats, potentially holding promise for human endodontic disease treatment pending further research.

Single nucleotide polymorphisms in inducible nitric oxide synthase gene are not associated with persistent apical periodontitis

The aim of this study was to investigate whether there is an association between inducible in single nucleotide polymorphisms in nitric oxide synthase (rs2297518 and rs2779249) and persistent apical periodontitis. A total of 291 Brazilian subjects were included: 125 with signs/symptoms of persistent apical periodontitis and 166 with root canal-treated teeth exhibiting healthy perirradicular tissues. Endodontically treated patients were followed up after 1 year. The two single nucleotide polymorphisms in nitric oxide synthase were analysed using real-time polymerase chain reaction. Chi-square test and odds ratio with 95% confidence intervals were performed to compare genotype distributions between 'healed' and 'persistent apical periodontitis' groups (p < 0.05). Logistic regression analysis was used to evaluate SNP-SNP interactions. The allele and genotype distributions for the polymorphisms between the persistent apical periodontitis and healed groups were not statistically significant (p > 0.05). In the logistic regression analysis, the polymorphisms were not associated with persistent apical periodontitis and SNP-SNP interactions.

The role of systemic statins in the inception and healing of apical periodontitis: a systematic review

OBJECTIVES

Statins are a category of medications widely used to reduce plasma LDL-cholesterol levels, that also possess antibacterial, anti-inflammatory, and immunomodulatory action. The aim of this systematic review was to explore the effects of systemic statins therapy on the development and treatment of apical periodontitis (AP) on humans and animals.

MATERIAL AND METHODS

Three electronic databases (PubMed, Web of Science, and Scopus) and grey literature were searched from their inception until February, 20 2023 (PROSPERO CRD42021246231). For the quality assessment and risk of bias, different guidelines were used according to the typology of the studies considered (Animal Research Reporting of In Vivo Experiments, Newcastle-Ottawa Quality Assessment Form for Cohort Studies, Systematic Review Centre for Laboratory animal Experimentation Risk of Bias tool and Tool to assess risk of bias in cohort studies of CLARITY Group).

RESULTS

Seven hundred eleven records were screened, and six articles were included for this qualitative review. The eligible studies showed a moderate overall quality and risk of bias. Human patients in treatment with statins exhibited a higher healing rate of AP following root canal treatment. In experimental animal models, statins had a beneficial effect on the development of AP.

CONCLUSIONS

Despite the limited number of studies and considering that most of them are on animals, our findings suggest that systemically administered statins make a positive contribution to prevent the development and help healing of AP.

CLINICAL RELEVANCE

There is an increased evidence that a pharmacologic adjunct to endodontic treatment may be considered to enhance healing of AP. Among other medications, statins seem to have a positive impact on the disease.

Genome-wide Association Study Identifies Novel Risk Loci for Apical Periodontitis

INTRODUCTION

Apical periodontitis (AP) is a common consequence of root canal infection leading to periapical bone resorption. Microbial and host genetic factors and their interactions have been shown to play a role in AP development and progression. Variations in a few genes have been reported in association with AP; however, the lack of genome-wide studies has hindered progress in understanding the molecular mechanisms involved. Here, we report the first genome-wide association study of AP in a large and well-characterized population.

METHODS

Male and female adults (n = 932) presenting with deep caries and AP (cases), or deep caries without AP (controls) were included. Genotyping was performed using the Illumina Expanded Multi-Ethnic Genotyping Array (MEGA). Single-variant association testing was performed adjusting for sex and 5 principal components. Subphenotype association testing, analyses of genetically regulated gene expression, polygenic risk score, and phenome-wide association (PheWAS) analyses were also conducted.

RESULTS

Eight loci reached near genome-wide significant association with AP (P < 5 × 10-6); gene-focused analyses replicated 3 previously reported associations (P < 8.9 × 10-5). Sex-specific and subphenotype-specific analyses revealed additional significant associations with variants genome-wide. Functionally oriented gene-based analyses revealed 8 genes significantly associated with AP (P < 5 × 10-5), and PheWAS analysis revealed 33 phecodes associated with AP risk score (P < 3.08 × 10-5).

CONCLUSIONS

This study identified novel genes/loci contributing to AP and specific contributions to AP risk in men and women. Importantly, we identified additional systemic conditions significantly associated with AP risk. Our findings provide strong evidence for host-mediated effects on AP susceptibility.

Genetic polymorphism of interleukins 6 and 17 correlated with apical periodontitis: A Cross-sectional study

Interleukins 6 and 17 act in bone resorption in the presence of infections of endodontic origin for host defense. Genetic polymorphisms may be associated with increased bone loss, represented by areas of large periapical lesions. This study aimed to verify the frequency of interleukin 6 and 17 gene polymorphism in patients with asymptomatic apical periodontitis or chronic apical abscess and to verify the existence of correlations between periapical lesion area with age, gender, and presence of the polymorphism, in the studied population, in the state of Pernambuco. A population consisting of thirty diagnosed individuals was included. The area of the lesions was measured in mm². Genomic DNA was extracted and genotyping was performed by Polymerase Chain Reaction Restriction Fragment Length Polymorphism for interleukin 6 (rs 1800795) and interleukin 17 (rs 2275913). Fisher's exact, chi-square, and odds ratio tests were used. A logistic regression analysis was also performed using sex, age, and the presence of polymorphism as covariates, in addition to linear regression to test the relationship between age and lesion area. All tests used a significance level of 0.05% (p ≤0.05%). There was no statistical significance in the occurrence of large areas of periapical lesions correlated with age, sex, and diagnosis, nor in the distribution of alleles in the polymorphism of interleukins 6 and 17 in the studied groups. The frequency of homozygous and heterozygous polymorphism was high. The polymorphism of these interleukins is not correlated with the increase in the areas of asymptomatic periapical inflammatory lesions.

The effect of low-dose aspirin on aspirin triggered lipoxin, interleukin 1 beta, and prostaglandin E2 levels in periapical fluid: a double-blind randomized clinical trial

BACKGROUND

The role of pro-resolving mediators in inflammation is a new concern in research. The effect of low-dose aspirin on production of a special kind of these mediators named aspirin triggered lipoxin (ATL) has been studied on different tissues. This randomized clinical trial evaluated the effect of low-dose aspirin on ATL and pro-inflammatory mediators' level in periapical fluid of necrotic teeth with large lesions.

METHODS

Twenty-four patients with necrotic pulp and periapical lesion were randomly assigned to low-dose aspirin and placebo groups. In the first appointment, canals were shaped up to F3 size and #40 K-file and cleaned with 10 milliliters 2.5% sodium hypochlorite and 17% Ethylenediaminetetraacetic acid. Periapical fluid was sampled by a paper cone. The tooth was temporized without any intracanal medication. Tablets were administered for 7 days, then the teeth were re-opened and the sampling were repeated. Interleukin-1 beta (IL-1β), prostaglandin E2 (PGE2) and ATL were analyzed by enzyme-linked immunosorbent assay. Data were analyzed with paired t-test using SPSS statistical software, version 21 (α = 0.05).

RESULTS

A significant reduction in PGE2 and IL-1β was noted in the aspirin-treated group while an increase in ATL was observed (P < 0.001). There was no significant difference in the mediator scores before and after in the placebo-treated group (P > 0.05).

CONCLUSION

Low-dose aspirin can influence the inflammatory process by reducing pro-inflammatory mediators such as PGE2 and IL-1β, as well as increasing the pro-resolving mediators such as ATL.

TRIAL REGISTRATION

IRCT20191211045702N1.

Factors that affect the outcomes of root canal treatment and retreatment-A reframing of the principles

This paper undertakes a broad and comprehensive synthesis of relevant clinical, biological, biomechanical, technical and healthcare services data to understand the factors affecting outcomes of periapical healing after root canal (re)treatment. The medical and dental evidence-based era (1980-present) is contextualized with the earlier evidence drive in endodontics (1911-1940) triggered by the focal infection era. The current evidence-based approach has a sharper focus on evidence quality and derivation of practice guidelines. Contrary views question whether guideline-driven, or expertise-development-driven endeavours would best serve outcome improvement in society. The endodontic discipline functions in a broad healthcare framework and sustains industrial, economic and trend pressures that may be deemed to influence outcomes. The nature of root canal treatment and the challenges in determining the factors that affect its outcomes is discussed. The factors potentially affecting periapical healing after root canal treatment are classified into pre-operative, intra-operative and postoperative groups. These categories subsume multiple elements with interactive influences, creating a complex picture, further confounded by some apparently surprising, counter-intuitive and contradictory findings. The technical versus biological conundrum in root canal treatment continues to cause cognitive dissonance. However, due reflection and cross-discipline-synthesis resolve the apparent data conflicts into a very simple, consistent and plausible picture of how root canal treatment works and the key factors that affect periapical healing. Root canal retreatment is considered mainly in the context of its differences from primary treatment as the majority of factors influencing outcomes are common to both. The exceptional difference is that retreatments have a proportionately reduced probability of healing by virtue of compromised apical root canal ramification access or modified host/infection interactions. Root canal (re)treatment outcomes are dominantly influenced by the nature of prior dynamic host/infection interaction (pre-operative patient factors) and how the direction of this dynamic is influenced by two factors: (1) the active efficacy of the operators' root canal treatment protocol to sustain a microbial ecological shift (intra-operative treatment factors) and dampen periapical inflammation; and (2) the passive ability of the functional tooth (and its restoration margin) to maintain its integrity to resist infection reversal (postoperative restorative factors).

Impact of systemic health on treatment outcomes in endodontics

BACKGROUND

The healing of periapical lesions after root canal treatment (RCT) is not the result of the curative action of the treatment. The process of healing begins with inflammation, and is resolved by the clearance of the immunogen that induces the immune response. Then, the periapical tissue itself carries out the healing of the periapical lesion, by repair or by a combination of repair and regeneration, depending on the host's reparative response working properly. The ultimate objective of RCT is to achieve wound healing by removing the source of bacterial antigens and toxins, allowing chronic inflammatory tissue to become reparative tissue. Some systemic conditions increase the susceptibility of the host to infection or impair the tissue reparative response, maintaining the inflammatory process and periapical bone resorption after RCT. This can cause the failure of RCT and even the need for extraction of the affected tooth.

OBJECTIVE

To analyse the scientific literature on the possible influence of systemic conditions on the treatment outcomes in endodontics, as well as to discuss the biological mechanisms that may be involved.

METHODS

The search was carried out in PubMed, SCOPUS and EMBASE. The inclusion criteria established were original scientific articles reporting data about some systemic condition in relation to treatment outcomes in endodontics, including clinical studies and studies carried out in animal models.

RESULTS

Systemic factors (age, nutrition, stress, hormones, smoking habits), and systemic diseases, such as diabetes, cardiovascular diseases, osteoporosis, HIV infection, inflammatory bowel disease, and others, can influence or interfere in the repair of periapical tissues after RCT.

DISCUSSION

Some of these systemic diseases can alter bone turnover and fibroblast function, preventing or delaying periapical wound healing. Others can alter the microvasculature, reducing nutrients and oxygen supply to periapical tissues. As a result, these systemic conditions can decrease the success rate of RCT and provoke incomplete wound healing (typically granulomatous tissue formation) in the periapical region.

CONCLUSIONS

The results of this narrative review show worse success rate of RCT, with higher percentage of postoperative radiolucent periapical lesions and higher proportion of non-retained teeth (RFT), associated with several systemic conditions, such as smoking habits and diabetes.

Creating an atlas of the bone microenvironment during oral inflammatory-related bone disease using single-cell profiling

Oral inflammatory diseases such as apical periodontitis are common bacterial infectious diseases that may affect the periapical alveolar bone tissues. A protective process occurs simultaneously with the inflammatory tissue destruction, in which mesenchymal stem cells (MSCs) play a primary role. However, a systematic and precise description of the cellular and molecular composition of the microenvironment of bone affected by inflammation is lacking. In this study, we created a single-cell atlas of cell populations that compose alveolar bone in healthy and inflammatory disease states. We investigated changes in expression frequency and patterns related to apical periodontitis, as well as the interactions between MSCs and immunocytes. Our results highlight an enhanced self-supporting network and osteogenic potential within MSCs during apical periodontitis-associated inflammation. MSCs not only differentiated toward osteoblast lineage cells but also expressed higher levels of osteogenic-related markers, including Sparc and Col1a1. This was confirmed by lineage tracing in transgenic mouse models and human samples from oral inflammatory-related alveolar bone lesions. In summary, the current study provides an in-depth description of the microenvironment of MSCs and immunocytes in both healthy and disease states. We also identified key apical periodontitis-associated MSC subclusters and their biomarkers, which could further our understanding of the protective process and the underlying mechanisms of oral inflammatory-related bone disease. Taken together, these results enhance our understanding of heterogeneity and cellular interactions of alveolar bone cells under pathogenic and inflammatory conditions. We provide these data as a tool for investigators not only to better appreciate the repertoire of progenitors that are stress responsive but importantly to help design new therapeutic targets to restore bone lesions caused by apical periodontitis and other inflammatory-related bone diseases.

Genome-wide association study identifies novel risk loci for apical periodontitis

Apical periodontitis (AP) is a common consequence of root canal infection leading to periapical bone resorption. Microbial and host genetic factors, and their interactions, have been shown to play a role in AP development and progression. Variations in a few genes have been reported in association with AP, however, the lack of genome-wide studies has hindered progress in understanding the mechanisms involved in AP. Here, we report the first genome-wide association study of AP in a well-characterized population. Male and female adults (n=932) presenting with deep caries with AP (cases) or without AP (controls) were included. Genotyping was performed using the Illumina Expanded Multi-Ethnic Genotyping Array. Single-variant association testing was performed adjusting for sex and five principal components. Subphenotype association testing, analyses of genetically regulated gene expression, polygenic risk score and phenome-wide association (PheWAS) analyses were also performed. Eight loci reached near-genome-wide significant association with AP (p < 5 x 10-6); gene-focused analyses replicated three previously reported associations (p < 8.9 x 10-5). Sex-specific and subphenotype analyses revealed additional significant associations with variants genome-wide. Functionally oriented gene-based analyses revealed eight genes significantly associated with AP (p < 5 x 10-5), and PheWAS analysis revealed 33 phecodes associated with AP risk score (p < 3.08 x 10-5). This study identified novel genes/loci contributing to AP and revealed specific contributions to AP risk in males and females. Importantly, we identified additional systemic conditions significantly associated with AP risk. Our findings provide strong evidence for host-mediated effects on AP susceptibility.

Genetic, Cellular and Molecular Aspects involved in Apical Periodontitis

The development, establishment and repair of apical periodontitis (AP) is dependent of several factors, which include host susceptibility, microbial infection, immune response, quality of root canal treatment and organism's ability to repair. The understanding of genetic contributions to the risk of developing AP and presenting persistent AP has been extensively explored in modern Endodontics. Thus, this article aims to provide a review of the literature regarding the biochemical mediators involved in immune response signaling, osteoclastogenesis and bone neoformation, as the genetic components involved in the development and repair of AP. A narrative review of the literature was performed through a PUBMED/MEDLINE search and a hand search of the major AP textbooks. The knowledge regarding the cells, receptors and molecules involved in the host's immune-inflammatory response during the progression of AP added to the knowledge of bone biology allows the identification of factors inherent to the host that can interfere both in the progression and in the repair of these lesions. The main outcomes of studies evaluated in the review that investigated the correlation between genetic polymorphisms and AP in the last five years, demonstrate that genetic factors of the individual are involved in the success of root canal treatment. The discussion of this review gives subsides that may help to glimpse the development of new therapies based on the identification of therapeutic targets and the development of materials and techniques aimed at acting at the molecular level for clinical, radiographic and histological success of root canal treatment.

Single nucleotide polymorphisms as a predisposing factor for the development of apical periodontitis-An umbrella review

BACKGROUND

The interaction between heredity and different environmental factors in the modification of apical periodontitis (AP) susceptibility and prediction of its progression remain poorly elucidated.

OBJECTIVES

This umbrella review aimed to (i) analyse the available relevant systematic reviews in an attempt to determine the association between genotype and allelic distribution of different single-nucleotide polymorphisms (SNPs) and the development of AP, (ii) report deficiencies and gaps in knowledge in this area and (iii) present recommendations to conduct future clinical studies and systematic reviews.

METHODS

A literature search was conducted using Clarivate Analytics' Web of Science, Scopus, PubMed and Cochrane Database of Systematic Reviews, from inception to October 2021, with no language restrictions, including a grey literature search. Systematic reviews with/without meta-analysis evaluating genotype and allelic distribution of different SNPs between adult patients with/ without AP were included. All other type of studies were excluded. The methodological quality was assessed using the A MeaSurement Tool to Assess systematic Reviews (AMSTAR)-2 tool. Two independent reviewers were involved in study selection, data extraction and appraising the included reviews; disagreements were resolved by a third reviewer.

RESULTS

The current study includes five systematic reviews. Three reviews performed meta-analysis. Three reviews were graded by AMSTAR 2 as 'critically low' quality, whereas the other two were graded as 'low' and 'moderate' quality. Two reviews indicated that carriers of specific genotypes and alleles of tumour necrosis factor-alpha (TNF-α) -308 G > A and interleukin 1-beta (IL-1β) + 3954 C/T gene polymorphisms are more susceptible to an acute and persistent form of AP. However, high heterogeneity was observed.

DISCUSSION

The statistical heterogeneity within included systematic reviews was a consequence of clinical and methodological diversity amongst primary studies. Although some of the included reviews suggested that carriers of specific genotype and/or allele of TNF-α -308 G > A and IL-1β + 3954 C/T SNPs are more susceptible to AP, their conclusions should be interpreted with caution.

CONCLUSIONS

No candidate genes could be identified as a definitive genetic risk or protective factor for the development and progression of AP, and further high-quality genome-wide association studies are warranted.

Present status and future directions of intracanal medicaments

Two fundamental goals of endodontic treatment are to prevent or treat apical periodontitis. From a predictive perspective, several variables can affect the outcome of root canal treatment. Some of these variables depend on intraoperative factors, which include irrigation technique, size of the apical preparation, use of intracanal medicaments or the number of appointments necessary to complete the treatment. However, the outcome may also be affected by host and microbial factors. The intensity of periradicular bone loss or tissue damage, the presence of preoperative pain and associated conditions such as mechanical allodynia and central sensitization, the anatomical complexity of the apical portion of the canal, and the virulence and longevity of the bacterial infection can all have a profound influence on the outcome. Furthermore, numerous medical conditions have been reported to decrease the capability of the immune system to heal the periapical tissues. It is the clinician's responsibility to analyse these variables and incorporate them into the disinfection strategy to maximize the chances of healing. This narrative review will focus on the present status of intracanal medicaments, the clinical indications for their use and future directions for research.

Profile of host cell responses to exposure to stressed bacteria in planktonic; dislodged, and intact biofilm mode

The host defense response to microbial challenge emerging from the root canal system leads to apical periodontitis. The aim of this study was to evaluate the expression of inflammatory cytokines and Nitric Oxide (NO) by macrophages after interaction with Enterococcus faecalis in the: plankton and dislodged biofilm mode; intact biofilm mode stimulated by calcium hydroxide (CH), CH and chlorhexidine (CHX) or Triple Antibiotic Paste (TAP). For this purpose, culture of macrophages from monocytes in human peripheral blood (N=8) were exposed to the different modes of bacteria for 24 hours. Subsequently, the cytokines, such as, Tumor Necrotic Factor- alfa (TNF-α), interleukin (IL)-1β, IL-6, IL-10; and NO were quantified by Luminex xMAP and Greiss reaction, respectively. In addition to the potential therapeutic effects of the intracanal medication, their antimicrobial activity against Enterococcus faecalis biofilm were also tested in vitro by confocal microscopy. The experiments` data were analyzed by the Kruskal-Wallis test with the Dunn post hoc test (α < 0.05). Bacteria in dislodged biofilm mode were shown to be more aggressive to the immune system than bacteria in plankton mode and negative control, inducing greater expression of NO and TNF-α. Relative to bacteria in intact biofilm mode, the weakest antimicrobial activity occurred in Group CH. In Groups CH/CHX and TAP the percentage of dead bacteria was significantly increased to the same extent. Interestingly, the biofilm itself did not induce the release of pro-inflammatory cytokines - except for NO - while the biofilm treated with TAP and CH based pastes enhanced the levels of IL-6 and TNF-α; and IL-1 β, respectively. In contrast, the levels of a potent anti-inflammatory (IL-10) were increased in Group TAP.

The quality of root canal treatment and periapical status of permanent teeth in Turkish children and teens: a retrospective CBCT study

OBJECTIVE

This study aimed to assess the quality of root canal fillings and the prevalence of periapical radiolucencies in the permanent teeth of 6-18 year-old Turkish children.

METHODS

CBCT images of 150 patients' 235 teeth with a mean age of 16.0 ± 2.06 years were included. Root development stage, quality of root canal filling, the presence and severity of periapical radiolucencies, and their relationship with anatomical structures were recorded. Correlations between the quality of root canal filling, periapical lesion, and lesion size were assessed using regression analyses.

RESULTS

A total of 235 teeth (528 root canals) were evaluated. 65.5% of root canals had periapical lesions. Immature roots and mandibular teeth had the highest prevalence and the largest size of periapical radiolucencies (p < 0.05). Overfilling (n = 52), underfilling (n = 93), unfilled (n = 46), inhomogeneously filled (n = 113) root canals and poor coronal restoration (n = 85 teeth) were observed in terms of technical failures of endodontic treatment. The quality of endodontic treatment was associated with the presence of periapical lesion and lesion size (p < 0.05). Teeth with under-filled, overfilled or inhomogeneously filled root canals and poor coronal restoration had a periapical lesion larger than 5 mm (p < 0.05). Immature teeth were most associated with the presence of lesion (OR = 4.07) and the lesion size > 5 mm (OR = 3.71).

CONCLUSION

The prevalence of periapical radiolucencies in young permanent teeth showed an increase when the tooth was an incisor, had incomplete root development, or the root filling had technical errors.

Periapical lesions in two inbred strains of rats differing in immunological reactivity

AIM

To investigate the influence of strain differences in immune responses on the pathogenesis of experimental periapical lesions in Dark Agouti (DA) and Albino Oxford (AO) inbred strains of rats.

METHODOLOGY

Periapical lesions were induced in male DA and AO rats by pulp exposure of the first mandibular right molars to the oral environment. Animals were killed 21 days after pulp exposure. The mandibular jaws were retrieved and prepared for radiographic, pathohistological, immunohistochemical analysis, real-time PCR and flow cytometry. Blood samples and the supernatant of periapical lesions were collected for measurement of cytokines and oxidative stress marker levels. Statistical analysis was performed using the Kruskal-Wallis H and Mann-Whitney U non-parametric tests or parametric One-Way anova and Independent Samples T-test to determine the differences between groups depending on the normality of the data. A significant difference was considered when p values were <.05.

RESULTS

DA rats developed significantly larger (p < .05) periapical lesions compared to AO rats as confirmed by radiographic and pathohistological analysis. The immunohistochemical staining intensity for CD3 was significantly greater in periapical lesions of DA rats compared to AO rats (p < .05). In DA rats, periapical lesions had a significantly higher (p < .05) percentage of CD3+ cells compared to AO rats. Also, the percentage of INF-γ, IL-17 and IL-10 CD3+CD4+ cells was significantly higher in DA rats (p < .05). DA rats had a significantly higher Th17/Th10 ratio. RT-PCR expression of IL-1β, INF-γ and IL-17 genes was significantly higher in periapical lesions of DA compared to AO rats (p < .05). The receptor activator of nuclear factor kappa-Β ligand/osteoprotegerin ratio was higher in DA compared to AO rats with periapical lesions (p < .05). Systemic levels of TNF-α and IL-6 were significantly higher in DA compared to AO rats (p < .05). Levels of lipid peroxidation measured as thiobarbituric acid reactive substances and reduced glutathione were significantly higher (p < .05) in the supernatant in the periapical lesions of DA rats.

CONCLUSION

After pulp exposure, DA rats developed much larger periapical lesions compared to AO rats. Genetically determined differences in immunopathology have been demonstrated to be a significant element defining the severity of periapical lesions.

Nonclinical research areas of future importance for clinical therapies: Exploring the concepts of nonlinearity in dentistry

Linear system analysis has been dominating medical and dental research, and most of the research achievements in these fields have come from applying a reductionist view of nature. However, biologic systems are fundamentally nonlinear with highly composite dynamics made up of numerous interacting elements and feedback loops, therefore studying them as linear models may not result in an accurate representation of their true features. The authors reviewed and utilized some of the principles of chaos and nonlinearity and extended them to clinical dentistry, from cracked tooth and flare-up after root canal procedures to the outcome of clinical treatments. Utilization of the concepts of chaos and sensitive dependence on initial conditions, and the concepts of self-organization, stigmergy, and fractals may help us to understand some of the puzzles that have not been solved by conventional linear models. The goal of this paper is to present some areas within nonclinical research that we believe will have important roles in the development of future clinical examination methods and therapies.

Inflammatory profile of apical periodontitis associated with liver fibrosis in rats: histological and immunohistochemical analysis

AIM

To investigate the effects of liver fibrosis (LF) on the pro-inflammatory mediators and periapical bone resorption of apical periodontitis (AP) in rats.

METHODOLOGY

Forty male Wistar rats were distributed into four groups: C - control, AP - rats with AP, LF - rats with LF, AP + LF - rats with AP and LF. LF was induced by carbon tetrachloride administration for 8 weeks and surgical bile duct ligation for 4 weeks; AP was induced in the teeth of rats by dental pulp exposure to the oral environment for 30 days. Jaws and livers were removed after euthanasia. Haematoxylin and Eosin (H&E) and Picrosirius Red (PSR) staining were used to confirm fibrosis in the livers. The jaws were analysed using H&E staining, immunohistochemical assays of interleukin (IL)-1β, IL-6 and tumour necrosis factor-alpha (TNF-α). Student's t-test and Mann-Whitney's U-test were used for statistical analysis (P < 0.05).

RESULTS

Inflammatory infiltrate was moderate in the AP group and severe in the AP + LF group (P < 0.05). Periapical bone resorption was significantly larger in the AP + LF group compared with the AP group (P < 0.05). IL-1β, IL-6 and TNF-α levels were significantly higher in AP + LF group when compared to the AP group (P < 0.05).

CONCLUSION

More intense inflammatory infiltrate, greater amounts of pro-inflammatory cytokines and increased periapical bone resorption were observed in the presence of liver fibrosis in rats with exposed pulps.

Proresolving Mediators in Endodontics: A Systematic Review

INTRODUCTION

Proresolving lipid mediators are specialized molecules (SPMs) involved in the active resolution of the inflammatory process by regulating tissue homeostasis. The aim of this study was to investigate the scientific literature to assess the potential of SPMs as an adjunct in the treatment of endodontic infection.

METHODS

Three electronic databases (PubMed, Web of Science, and Scopus) were searched from their inception until February 2020 (PROSPERO CRD42020164743). Supplemental research was performed by screening the references of the relevant studies eligible for inclusion. A quality assessment of animal studies was performed using the Animal Research: Reporting of In Vivo Experiments guidelines, whereas the Systematic Review Centre for Laboratory animal Experimentation Risk of Bias tool was used to assess the risk of bias.

RESULTS

A total of 3295 records were screened, and 8 articles meeting the criteria were included for this qualitative review. The eligible studies showed a high to moderate overall quality and a low to moderate risk of bias. SPMs positively affected the development of pulpitis and apical periodontitis in experimental animal models. The early treatment of pulpitis with the topical application of SPMs was beneficial to control inflammation within 24 hours from contamination. In addition, SPMs delivered within the root canals after disinfection were found effective in promoting periapical healing.

CONCLUSIONS

Our findings suggest that SPMs may play a role in the inception and treatment of pulpal-periapical diseases, and they should be considered for future research for developing new therapeutics as an adjunct to endodontic treatment.

Investigation of Genetic Polymorphisms in BMP2, BMP4, SMAD6, and RUNX2 and Persistent Apical Periodontitis

INTRODUCTION

This study aimed to evaluate the interplay among single-nucleotide polymorphisms (SNPs) in the encoding genes BMP2, BMP4, SMAD6, and RUNX2 in persistent apical periodontitis (PAP).

METHODS

In this multicentric study, 272 patients diagnosed with pulp necrosis with apical periodontitis before root canal therapy who attended regular follow-up visits for at least 1 year were screened. Periapical radiographs and clinical aspects were evaluated, and the participants were classified as PAP (n = 110) or repaired (n = 162). Genomic DNA was used for the genotyping of the following SNPs: rs1005464 and rs235768 in bone morphogenetic protein 2 (BMP2), rs17563 in bone morphogenetic protein 4 (BMP4), rs2119261 and rs3934908 in SMAD family member 6 (SMAD6), and rs59983488 and rs1200425 in runt-related transcription factor 2 (RUNX2). The chi-square test was used to compare genotype distributions between groups. The multifactor dimensionality reduction method was applied to identify SNP-SNP interactions. The alpha for all the analysis was 5%.

RESULTS

The multifactor dimensionality reduction suggested the rs235768 in BMP2 and rs59983488 in RUNX2 as the best SNP-SNP interaction model (cross-validation = 10/10, testing balanced accuracy = 0.584, P = .026) followed by rs17563 in BMP4 and rs2119261 in SMAD6 (cross validation = 10/10, testing balanced accuracy = 0.580, P = .031). In the rs235768 in BMP2 and rs59983488 in RUNX2 model, the high-risk genotype was TT + TT (odds ratio = 4.36; 95% confidence interval, 0.44-42.1). In model rs17563 in BMP4 and rs2119261 in SMAD6, GG + TT (odds ratio = 2.63; 95% confidence interval, 0.71-11.9) was the high-risk genotype.

CONCLUSIONS

The interactions between rs235768 in BMP2 and rs59983488 in RUNX2 and between rs17563 in BMP4 and rs2119261 in SMAD6 are associated with PAP, suggesting that an interplay of these SNPs is involved in the higher risk of developing PAP.

MicroRNA-223 negatively regulates LPS-induced inflammatory responses by targeting NLRP3 in human dental pulp fibroblasts

AIM

To investigate the effect of miR-223 on NLRP3, subsequently regulating the production of the NLRP3/CASP1 inflammasome pathway-mediated proinflammatory cytokines IL-1β and IL-18 in human dental pulp fibroblasts (HDPFs).

METHODOLOGY

Human dental pulp tissue (HDPT) and HDPFs were obtained from impacted third molars. The miR-223 mimics and inhibitor or NLRP3 plasmid were used to upregulate or downregulate miR-223 or NLRP3 in HDPFs, respectively. Computational prediction via TargetScan 5.1 and a luciferase reporter assay was conducted to confirm target association. The mRNA and protein expression of NLRP3, caspase-1, IL-1β and IL-18 was determined by qRT-PCR and Western blotting, respectively. The release of IL-1β and IL-18 was analysed by ELISA. The significance of the differences between the experimental and the control groups was determined using one-way analysis of variance; P < 0.05 indicated statistical significance.

RESULTS

A decrease in miR-223 and an increase in NLRP3 in HDPT occurred during the transformation of reversible pulpitis into irreversible pulpitis compared to that in healthy pulp tissue (P < 0.05). The computational prediction and luciferase reporter assay confirmed that NLRP3 was a direct target of miR-223 in HDPFs. The miR-223 inhibitor further promoted ATP plus LPS-induced NLRP3/CASP1 inflammasome pathway activation compared to the ATP plus LPS-induced group (P < 0.05). In contrast, the miR-223 mimic significantly inhibited the NLRP3/CASP1 inflammasome pathway activation induced by ATP plus LPS compared to the ATP plus LPS-induced group (P < 0.05).

CONCLUSION

MiR-223 served as a negative regulator involved in the control of the production and secretion of proinflammatory cytokines mediated by the NLRP3/CASP1 inflammasome pathway by targeting NLRP3. These data provide insight into the potential regulatory effects of miRNAs on the NLRP3 inflammasome, thus opening up novel potential therapeutic avenues for future endodontic treatment.

Association between genetic polymorphisms in the promoter region of the defensin beta 1 gene and persistent apical periodontitis

AIM

To evaluate the association between the promoter region of defensin beta 1 (DEFB1) genetic polymorphisms and persistent apical periodontitis (PAP) in Brazilian patients.

METHODOLOGY

Seventy-three patients with post-treatment PAP (PAP group) and 89 patients with root filled teeth with healed and healthy periradicular tissues (healed group) were included (all teeth had apical periodontitis lesions at the beginning of the treatment). Patients who had undergone at least 1 year of follow-up after root canal treatment were recalled, and their genomic DNA was extracted from saliva. Two single nucleotide polymorphisms (SNPs) in DEFB1 at the g. -52G>A (rs1799946) and g. -20G>A (rs11362) positions were analysed using real-time polymerase chain reaction. The chi-squared test was performed, and the odds ratios were calculated using Epi Info 3.5.2. Logistic regression analysis in the codominant model, using the time of follow-up as a variable, was used to evaluate the SNP-SNP interaction. All tests were performed with an established alpha of 0.05 (P = 0.05).

RESULTS

For the rs11362 polymorphism in the codominant and recessive models, patients who carried two copies of the T allele had a significantly lower risk of developing PAP (P = 0.040 and P = 0.031, respectively). For the rs1799946 polymorphism in DEFB1 in the codominant and recessive models, carrying one copy of the T allele significantly increased the risk of developing PAP (P = 0.007 and P = 0.031, respectively). In the logistic regression, both polymorphisms were associated with PAP as well as the SNP-SNP interaction (P < 0.0001).

CONCLUSIONS

Polymorphisms in DEFB1 genes were associated with the development of post-treatment persistent apical periodontitis.

Immunological profile of periapical endodontic infection in patients undergoing haematopoietic transplantation

OBJECTIVES

To evaluate the mRNA expression levels of cytokines interferon-γ, tumour necrosis factor-α, interleukin IL-1β, IL-10, and the chemokine CCL2/MCP-1, CCL4, and CXCR4 in the periapical interstitial fluid from root canal infections before and after bacterial load reduction in patients undergoing haematopoietic stem cell transplantation (HSCT).

MATERIALS AND METHODS

The case group was composed of 10 patients undergoing HSCT, and our control group included 10 healthy patients. Clinical samples were taken from teeth with pulp necrosis. Three paper points were placed in the RCS and maintained for 2 min for microbial evaluation before cleaning and shaping procedures. After cleaning and drying the canal, three paper points were introduced into the root canal, passing passively through the root apex (2 mm) into the periapical tissues for 1 min. Samples were collected immediately after root canal cleaning and 7 days later (restrained root canal bacterial load) to characterize gene expression using real-time PCR.

RESULTS

The results showed significantly reduction in the microbial load on day 7. An increased expression level of TNF-α and IFN-γ on day 7 in control and case groups was observed (p < 0.05). The mRNA levels of IL-1β and IL-10 in the pre-HSCT group increased in the samples from day 7 (p < 0.05). The chemokine CCL-2/MCP-1 was not detected in pre-HSCT group. Chemokine receptor CXCR4 levels increased in samples obtained from the day 7 in the control group (p < 0.05).

CONCLUSIONS

Individuals undergoing HSTC presented similar cytokine and chemokine mRNA expression compared with healthy individuals. However, it was observed the total absence of mRNA MCP-1/CCL2 expression in those individuals undergoing HSCT.

CLINICAL RELEVANCE

Patients undergoing HSCT are at higher risk of infection. No study has analysed the periapical immune responses to root canal infections in HSCT individuals.

Genetic and Epigenetic Characterization of Pulpal and Periapical Inflammation

Pulpal and periapical diseases affect a large segment of the population. The role of microbial infections and host effector molecules in these diseases is well established. However, the interaction between host genes and environmental factors in disease susceptibility and progression is less well understood. Studies of genetic polymorphisms in disease relevant genes have suggested that individual predisposition may contribute to susceptibility to pulpal and periapical diseases. Other studies have explored the contribution of epigenetic mechanisms to these diseases. Ongoing research expands the spectrum of non-coding RNAs in pulpal disease to include viral microRNAs as well. This review summarizes recent advances in the genetic and epigenetic characterization of pulpal and periapical disease, with special emphasis on recent data that address the pathogenesis of irreversible pulpal pathosis and apical periodontitis. Specifically, proinflammatory and anti-inflammatory gene expression and gene polymorphism, as well as recent data on DNA methylation and microRNAs are reviewed. Improved understanding of these mechanisms may aid in disease prevention as well as in improved treatment outcomes.

Association between Estrogen, Vitamin D and Microrna17 Gene Polymorphisms and Periapical Lesions

Abstract This study evaluated the association between polymorphisms in genes encoding estrogen receptors 1 (ESR1) and 2 (ESR2), vitamin D receptor (VDR) and in microRNA17 (which binds to ESR1 and VDR) with persistent apical periodontitis (PAP) after the endodontic treatment. We included 162 patients who completed endodontic treatment at least one year ago and presented apical periodontitis at the beginning of the root canal therapy. Clinical and radiographic exams were performed to evaluate the presence of PAP or healthy periradicular tissues (healed). Saliva samples were collected as a genomic DNA. The genotyping of ESR1 (rs2234693 and rs9340799), ESR2 (rs1256049 and rs4986938), VDR (rs739837 and rs2228570) and miRNA17 (rs4284505) were performed by real-time PCR. Chi-square test was used to the distribution of genotype and allele frequencies. Haplotype analysis was also performed. Eighty-nine patients were included in the “healed” group and 73 in the “PAP” group. No association was found between the allelic and genotypic polymorphisms studied and PAP (p>0.05). Haplotype analysis also did not demonstrated an association (p>0.05). In conclusion, the genetic polymorphisms in ESR1, ESR2, VDR and miRNA17 are not associated with PAP.

The Role of TNF-α as a Proinflammatory Cytokine in Pathological Processes

TNF-α is a member of the vast cytokine family being considered a proinflammatory substance produced many by macrophages and other cells belonging to the innate immunity, many of them classified as indeed Antigen Presenting Cells (APCs) involved in the complex chemotactic process of activation of the adaptive immunity. The aim of this work was to accomplish a literature review concerning the main pathologies that have TNF-α as a modulating agent in other to bring light to the main interactions present in the inflammation installed.

Potential role of TP63 in apical periodontitis development

AIM

To investigate the expression of TP63 in apical periodontitis (AP) tissues and the association of single nucleotide polymorphisms (SNPs) in the TP63 gene with AP using a case-control dataset.

METHODOLOGY

Expression of TP63 in human AP lesions (apical abscess, radicular cyst, periapical granuloma) was evaluated using immunohistochemistry. A case-control association study was performed to assess the association of TP63 polymorphisms in individuals having AP with or without associated pain. Cases were defined as subjects with deep caries and AP (n = 151) and subjects with symptomatic apical periodontitis or acute apical abscess (n = 124). Subjects without AP (n = 169) and asymptomatic (n = 196) were used as controls, respectively. Saliva samples were collected as source of genomic DNA. Twelve SNPs in the TP63 gene were selected for genotyping using Taqman chemistry in real-time PCR. Data analysis was performed using PLINK software. The Bonferroni method was applied to correct for multiple testing; α ≤ 0.004 indicates significant differences between groups.

RESULTS

TP63 expression was evident in apical abscesses and radicular cysts, while weaker expression was observed in periapical granulomas. Positive expression was observed in mononuclear cells in the granulation tissues of all AP lesions. Regarding the presence of AP, a trend for allelic association was observed for rs16864812 and rs9810322 (P = 0.04) and rs9810322 genotypes were also nominally associated with AP under a dominant model (P = 0.04). When considering the presence of periapical pain, a trend for allelic and genotypic association was observed for rs10155037 (P = 0.03). Haplotypes were also associated with AP and periapical pain (P ≤ 0.05).

CONCLUSIONS

Apical periodontitis is a complex multifactorial condition and it is likely that multiple genes and environmental effects may influence its susceptibility, progression or both. TP63 variants may play a role in AP pathogenesis and susceptibility, individually or interactively with other genes. Additional studies in other populations and functional studies are needed to improve understanding of the role of TP63 in AP.

Increased interleukin 1α and interleukin 1β expression is involved in the progression of periapical lesions in primary teeth

BACKGROUND

Interleukin 1 (IL-1) is involved in bone resorption. However, the role of IL-1 in periapical lesions characterized by periapical bone destruction in primary teeth has not yet been fully elucidated. This study aimed to detect the distribution and expression of IL-1 in periapical lesions in primary teeth and assess the relationship between the cytokines and the degree of inflammatory cell infiltration.

METHODS

A total of 106 chronic periapical lesions in primary teeth were harvested. Haematoxylin and eosin (H&E) staining was used to determine the histological type and the inflammatory cell infiltration grade (mild, moderate, and severe), and immunohistochemistry and enzyme-linked immunosorbent assay (ELISA) were used to detect the distribution and expression of IL-1α and IL-1β.

RESULTS

Of the 106 chronic periapical lesion samples, there were 85 cases of periapical granuloma, accounting for 80.19% of the total samples, and 21 cases of radicular cysts, accounting for 19.81%; no cases of abscess were detected. Immunohistochemistry results showed that both IL-1α and IL-1β were expressed in periapical granulomas and cysts. ELISA results showed that IL-1α and IL-1β levels were higher in the periapical granuloma group than in the radicular cyst and normal control groups (P < 0.05). In the periapical granuloma group, IL-1α and IL-1β were detected at higher levels in the severe inflammatory cell infiltration subgroup than in the mild-inflammatory cell infiltration subgroup (P < 0.05), and IL-1β expression was also higher in the moderate inflammatory cell infiltration subgroup than in the mild inflammatory cell infiltration subgroup (P < 0.01). A significant positive correlation was observed between the protein expression levels of IL-1α and IL-1β and the inflammation grade in periapical granulomas from primary teeth (P < 0.05).

CONCLUSION

Expression levels of the cytokines IL-1α and IL-1β in periapical granulomas from primary teeth increased with increasing inflammatory severity and appeared to be a contributing factor to the progression of periapical lesions.

Arg753gln and Arg677 Trp Polymorphisms of Toll-Like Receptor 2 In Acute Apical Abscess

STATEMENT OF THE PROBLEM

Genetic polymorphisms can alter immunity response against pathogens, which in turn influence individuals' susceptibility to certain infections.

PURPOSE

Our aim was to determine the association of Arg753Gln (rs5743708) and Arg677Trp (rs12191786) polymorphisms of toll like receptor-2 gene with the two clinical forms of apical periodontitis: acute apical abscess (AAA) and asymptomatic apical periodontitis (AAP).

MATERIALS AND METHOD

There were 50 patients with AAA as case group and 50 with AAP as control group. Genotyping was done using Tetra-ARMS (amplification refractory mutation system) PCR.

RESULTS

Heterozygous genotype of Arg677Trp polymorphism was associated with risk of AAA (OR=1.9, 95% CI: 0.7-5.5, p= 0.05). Although statistically insignificant, Arg677Trp polymorphism promoted the risk of AAA in dominant model (OR=2.1, 95% CI: 0.7-5.9, p> 0.05). The frequency of mutant allele (T) of Arg677Trp polymorphism was higher in AAA (14%) than AAP (7%) subjects (OR=1.7, 95% CI: 0.6-4.7). For Arg753Gln polymorphism, wild homozygous (GG) represented the dominant genotype in both cases (96%) and controls (100%). Variant allele (A) of Arg753Gln polymorphism was identified in 2% of AAA, while no individual represented with this allele in AAP subjects. Individuals with Arg753Gln; Arg677Trp (GG; TC) combination showed an elevated risk of AAA (OR=1.6, 95% CI: 0.5- 4.2, p> 0.05).

CONCLUSION

Arg677Trp polymorphism of TLR-2 rendered a higher risk for the development of abscesses in apical periodontitis. It is recommended to explore role of this polymorphism in other populations.

Influence Of Genetic Polymorphisms In Genes Of Bone Remodeling And Angiogenesis Process In The Apical Periodontitis

Abstract Persistent apical periodontitis (AP) is a situation involving an inflammatory and immune response caused mainly by anaerobic polymicrobial infection of the root canal system and the outcome and follow-up of the root canal treatment has been reported as intimately related to host response. The apical periodontitis repair might be associated with genetic polymorphisms. This study aimed to evaluate the association between HIF1A genetic polymorphisms (rs2301113 and rs2057482) with PAP in Brazilian patients. Subjects with at least 1 year of follow-up after root canal therapy (RCT) were recalled. Sixty-four subjects with signs/symptoms of PAP and 84 subjects with root canal-treated teeth exhibiting healthy perirradicular tissues (healed) were included. Genomic DNA was extracted from saliva and used for HIF1A genotyping by real-time PCR. Genotype and allele frequencies were compared by c2 or Fisher’s exact tests and odds ratio was implemented, using Epi Info 3.5.2. All tests were performed with an established alpha of 0.05. There was no association between allele and genotype distribution for HIF1As polymorphisms and PAP (p>0.05). The genetic polymorphisms in HIF1A were not associated with persistent apical periodontitis.

Association between Apical Periodontitis and Interleukin Gene Polymorphisms: A Systematic Review and Meta-analysis

INTRODUCTION

Genetic polymorphisms may result in altered gene expression or functional changes of the encoded molecules and could possibly generate a deficient immunity. Consequently, individuals with specific genotypes could be more susceptible to disease or could present an increase in disease severity. Our study is aimed to verify, through a systematic review and meta-analysis registered in the PROSPERO database (CRD42016043905), whether currently available evidence supports a relationship between interleukin gene polymorphisms and apical periodontitis (AP).

METHODS

A broad search for studies was conducted. The following databases were used: PubMed, Scopus, Web of Science, and the Virtual Health Library (MEDLINE, SciELO, IBECS, and LILACS). The Medical Subject Headings (MeSH) terms "Periapical Periodontitis," "Periapical Abscess," "Polymorphism, Genetic," and "Polymorphism, Single Nucleotide" were used. MeSH synonyms, related terms, and free terms were included. After application of the eligibility criteria, selected studies were qualified by assessment of their methodologic quality. A fixed effects model was used for the meta-analysis.

RESULTS

The initial search identified 71 references. After excluding duplicate abstracts, 33 were selected. From these, 6 were eligible for quality assessment; 5 were classified as being of moderate quality, and 1 was classified as being of high quality.

CONCLUSIONS

From these included studies, polymorphisms in IL1B, IL6, and IL8 were associated with AP. Polymorphisms in IL1A, IL10, or IL12B were not associated with AP regardless of the methodology used. The meta-analysis suggested that the genotype and allele distribution of IL1B (+3954 C/T) gene polymorphism was different in post-treatment AP. More research in this area is warranted to confirm these results.

Prevalence of Apical Periodontitis in Patients with Inflammatory Bowel Diseases: A Retrospective Clinical Study

AIM

We evaluated the prevalence of apical periodontitis (AP) and the oral health status in patients with inflammatory bowel diseases (IBDs) treated with immunomodulators, with particular attention to biologic medications (BMs).

METHODS

One hundred ten patients, 49 men and 61 women (average age, 46 ± 13.8 years), from the Gastroenterology Unit of the University Hospital with IBDs who were treated with BMs or corticosteroids were included in the study. One hundred ten patients who registered for a dental check-up at the Dental Clinic were matched for age, sex, and physical characteristics with the study group without systemic diseases and not taking medications who were the control. Patients underwent a complete oral, dental, and radiographic examination. Decayed, missing, and filled teeth and periapical index score indexes were recorded. Student t test, χ², and Mann-Whitney U test were used as appropriate.

RESULTS

The prevalence of AP was 64% in IBD patients and 59% in the control; according to the gender-stratified analysis, the difference was not significant among the male groups, whereas the number of teeth with AP was significantly higher in female patients with IBDs than in the controls (P ≤ .05). The prevalence of AP in patients treated with BMs was 65%; women showed 69% higher risk for AP and presented a significantly higher number of teeth with AP (P ≤ .05). Decayed, missing, and filled teeth index was similar in both groups, whereas patients with IBDs had a higher periapical index score than the controls.

CONCLUSIONS

Women with IBDs and taking immunomodulators had a higher prevalence of AP. All patients with IBDs had larger lesions than healthy subjects. These data emphasize the influence of the status of the immune system in the onset of AP and the need for further studies to confirm these findings.

Survival Rates of Teeth with Primary Endodontic Treatment after Core/Post and Crown Placement

INTRODUCTION

The objective of this study was to determine the effect of delayed placement of the core/post and crown on the outcomes of nonsurgical root canal therapy (NSRCT).

METHODS

According to the Delta Dental of Wisconsin claims database, 160,040 NSRCTs were completed with a core/post and a crown placed before the end of the continuous coverage period or occurrence of an untoward event. Untoward events were defined as a retreatment, apicoectomy, or extraction as defined by the Code on Dental Procedures and Nomenclature. Statistical analysis was performed by using a multivariable Cox proportional hazards model.

RESULTS

The survival rate from the time of crown placement to an untoward event was 99.1% at 1 year, 96.0% at 3 years, 92.3% at 5 years, and 83.8% at 10 years. Failure rates were greater when a core/post was placed more than 60 days after the NSRCT (adjusted hazard ratio, 1.08) and when the crown was placed more than 60 days after the core/post placement (adjusted hazard ratio, 1.14). Overall, the survival rates of NSRCT were greater when performed by an endodontist versus other providers.

CONCLUSIONS

On the basis of the information available from insurance claims data, this study shows that the long-term survival rates of initial endodontic therapy are adversely affected by the delayed placement of the final restoration and full coverage crown.

The Influence of Adalimumab on the Healing of Apical Periodontitis in Ferrets

INTRODUCTION

Given the increasing use of anti-tumor necrosis factor α (anti-TNFα) biologic medications, and their interferences with the immune-inflammatory response, this study evaluated the effect of adalimumab (anti-TNFα), on healing and healing time of apical periodontitis (AP) in ferrets.

METHODS

Twelve male ferrets received cone beam computed tomography of the jaws at baseline health (T0); AP confirmation (T1); and 30 (T2), 60 (T3), and 90 (T4) days after root canal treatment (RCT) to monitor healing. All animals had AP induced in the canines; 3 ferrets (12 teeth) provided the positive controls for the histologic evaluation; 9 ferrets were randomly divided into 3 treatment groups with 12 teeth each in the following manner: Systemic: conventional RCT and systemic anti-TNFα; Local: RCT and periapical administration of anti-TNFα before canal obturation; conventional RCT only (control). Two calibrated radiologists assessed the cone beam computed tomography images independently and blindly for AP identification and quantification. Rank-based analysis of covariance was used for statistical analysis of lesion size.

RESULTS

AP was induced in all teeth. Following RCT, all AP lesions in the 3 groups showed a significant reduction in size. Specific pairwise comparisons of the related samples (Friedman's 2-way analysis of variance by ranks within each group) demonstrated a decreasing trend in lesion size with healing time in all 3 groups, most pronounced for local group (local adalimumab). No statistical difference was noticed between groups.

CONCLUSIONS

Both systemic and local anti-TNFα did not hinder AP healing in this animal model and a faster healing response may also be anticipated. These findings encourage follow-up studies with larger sample sizes.

Association Between Apical Periodontitis and TNF-α -308 G>A Gene Polymorphism: A Systematic Review and Meta-Analysis

Abstract Currently, investigations have focused on the identification of Single Nucleotide Polymorphisms (SNP) involved in host response and its ability to generate an immunity deficiency. The aim of this study was to perform a systematic review (SR) and meta-analysis to evaluate the association between TNF-α -308 G>A polymorphism and apical periodontitis (AP) phenotypes. A broad search for studies was conducted. The following databases were used: PubMed, Scopus, Web of Science, and VHL (Medline, SciELO, Ibecs, and Lilacs). The MeSH terms “Periapical Periodontitis,” “Periapical Abscess,” “Polymorphism, Genetic,” and “Polymorphism, Single Nucleotide” were used. MeSH synonyms, related terms, and free terms were included. Clinical investigations of individuals with different AP phenotypes in permanent teeth were selected. After application of the eligibility criteria, selected studies were qualified by assessing their methodological quality. A fixed effect model was used for the meta-analysis. The initial search identified 71 references. After excluding duplicate abstracts, 33 were selected. From these, two were eligible for quality assessment and were classified as being of moderate evidence. The included studies did not demonstrate association between AP and TNF-α -308 G>A SNP. However, the meta-analysis demonstrated an association between the genotype distribution and AP phenotype (OR= 0.49; confidence interval= 0.25, 0.96; p=0.04). The role of TNF-α -308 G>A SNP in AP phenotypes is debatable. Further studies are needed to confirm and understand the underlying mechanisms of the identified association.

Role of Thr399Ile and Asp299Gly polymorphisms of toll-like receptor-4 gene in acute dental abscess

BACKGROUND

Apical Periodontitis (AP) is an inflammatory disease that affects the tissues surrounding the root end of a tooth. The disease which is caused by endodontic infections presents in different clinical ways including development of an acute abscess. Recent studies have provided information suggesting role of a multitude of factors in pathogenesis of acute apical abscess (AAA). In this case-control study, our goal was to evaluate the frequency and potential role of two common polymorphisms of toll like receptor-4 (TLR-4) gene; Thr399Ile (1196 C>T) and Asp299Gly (+896 A>G), in 50 patients with AAA as cases and 50 patients with asymptomatic apical periodontitis (AAP) as controls.

MATERIAL AND METHODS

Saliva sample containing mucosal epithelial cells was used for DNA extraction. Polymorphisms were detected by Tetra-ARMS (Amplification Refractory Mutation System) PCR method. Statistical analyses were carried out in SPSS 21 software.

RESULTS

Homozygous wild type (CC) and heterozygous (CT) genotypes of Thr399Ile polymorphism were detected in 84% and 16% of AAA patients respectively. In controls, respective ratios were 94% (CC) and 6% (CT). Observed difference was not statistically significant (P>0.05) for distribution of these genotypes. The mutant homozygous (TT) genotype of this polymorphism was identified in neither of the participants. Overall, T allele frequency was obtained 8% in AAA and 3% in AAP (OR=2.6, 95% CI; 0. 6-10.6, p>0.05). For Asp299Gly polymorphism, no individual was detected with the mutant allele in case or control groups.

CONCLUSIONS

Our results indicated a possible role for Thr399Ile polymorphism in acute presentations of abscess in AAA. However, the impact of this polymorphism needs to be more assessed in future studies. Key words:Genetic polymorphism, periapical abscess, periapical periodontitis, toll-like receptor 4.

Heat Shock 70 Protein Genes and Genetic Susceptibility to Apical Periodontitis

INTRODUCTION

Heat shock proteins (HSPs) protect cells under adverse conditions such as infection, inflammation, and disease. The differential expression of HSPs in human periapical granulomas suggests a potential role for these proteins in periapical lesion development, which may contribute to different clinical outcomes. Therefore, we hypothesized that polymorphisms in HSP genes leading to perturbed gene expression and protein function may contribute to an individual's susceptibility to periapical lesion development.

METHODS

Subjects with deep carious lesions with or without periapical lesions (≥3 mm) were recruited at the University of Texas School of Dentistry at Houston and at the University of Pittsburgh. Genomic DNA samples of 400 patients were sorted into 2 groups: 183 cases with deep carious lesions and periapical lesions (cases) and 217 cases with deep carious lesions but without periapical lesions (controls). Eight single nucleotide polymorphisms (SNPs) in HSPA4, HSPA6, HSPA1L, HSPA4L, and HSPA9 genes were selected for genotyping. Genotypes were generated by end point analysis by using Taqman chemistry in a real-time polymerase chain reaction assay. Allele and genotype frequencies were compared among cases and controls by using χ(2) and Fisher exact tests as implemented in PLINK v.1.07. In silico analysis of SNP function was performed by using Polymorphism Phenotyping V2 and MirSNP software.

RESULTS

Overall, SNPs in HSPA1L and HSPA6 showed significant allelic association with cases of deep caries and periapical lesions (P < .05). We also observed altered transmission of HSPA1L SNP haplotypes (P = .03). In silico analysis of HSPA1L rs2075800 function showed that this SNP results in a glutamine-to-lysine substitution at position 602 of the protein and might affect the stability and function of the final protein.

CONCLUSIONS

Variations in HSPA1L and HSPA6 may be associated with periapical lesion formation in individuals with untreated deep carious lesions. Future studies could help predict host susceptibility to developing apical periodontitis.

Association of Toll-like receptors 2, 3, and 4 genes polymorphisms with periapical pathosis risk

Background

The aim of this study was to investigate the role of gene variations of Toll-like receptors (TLR) 2, 3, and 4 on genetic susceptibility to periapical pathosis.

Material and Methods

One hundred patients were included in the study and divided into two groups as follows; Control Group (n=50) that have root canal treatment and no periapical lesion, Patient Group (n=50) that have root canal treatment and periapical lesion. TLR2 Arg753Gln, TLR3 (c.1377C/T) and TLR4 Asp299Gly and Thr399Ile polymorphisms were genotyped by using PCR-RFLP. Genotypical analysis of control and patient groups were investigated to disclose whether there is any association between periapical lesions and gene variations.

Results

There are no significant statistical differences between control and patient groups according to TLR 2 and 4 gene sequence. On the contrary, CC allele detected 74% for TLR 3 in patient group, and this difference was found to be statistically significant (p < 0.005).

Conclusions

According to these results, it can be suggested that patients with Toll-like receptor 3 gene polymorphisms could be susceptible to periapical pathosis.

Key words:Toll-like receptors, periapical pathosis, endodontics.

Influence of oestrogen deficiency on the development of apical periodontitis

AIM

To evaluate the effects of a long period of oestrogen deficiency on the development of apical periodontitis in rats.

METHODOLOGY

Wistar rats (n = 24), 3 months old, evaluated by vaginal cytology, were included in the study. Twelve animals were ovariectomized (OVX group) and the other 12 were sham operated (control group). One hundred and twenty days after castration, the pulps of the left mandibular first molars were exposed to induce the development of apical periodontitis. Body mass was verified on a weekly basis. Following 21 and 40 days of lesion induction, the animals were sacrificed. Blood was collected for biochemical analysis, and mandibles were removed for radiographic analysis. Comparative analysis of the data was performed by the nonparametric Kruskal-Wallis and Dunn's multiple-comparisons tests. The t-test was applied to compare the oestrogen levels between control and OVX groups.

RESULTS

Radiographs revealed that apical periodontitis lesions were significantly larger in the 40-day OVX group when compared with both 40-day (P < 0.05) and 21-day (P < 0.001) control groups. Serum oestrogen levels were significantly lower in the OVX group (P < 0.01), confirming the efficacy of castration. Oestrogen deficiency resulted in significantly greater body mass gain (P < 0.01) in 40-day OVX group when compared with 40-day control group. Serum concentrations of calcium were similar between groups (P > 0.05). Alkaline phosphatase levels, although higher in the OVX groups (21 and 40 days), were not significantly different.

CONCLUSIONS

Ovariectomized rats had significantly larger apical periodontitis lesions after 40 days of pulp exposure when compared with controls. These findings suggest that bone alterations as a result of long periods of oestrogen deficiency can influence the progression of apical periodontitis.