Diabetes mellitus and the healing of periapical lesions in root filled teeth: a systematic review and meta‐analysis

Success and failure of endodontic treatment: predictability, complications, challenges and maintenance

The fundamentals of successful endodontic treatment are an awareness of the aetiology of the disease process and an understanding of factors that affect outcome. This paper aims to outline the prognostic factors found in the endodontic outcome literature to facilitate options appraisal and predictable treatment delivery. We will discuss pre-treatment, treatment and post-treatment factors. In summary, the significance of infection control throughout treatment, provision of an adequate coronal seal and appropriate restoration of the root-filled tooth are highlighted.

Angiogenic effects of Type 2 diabetes on the dental pulp

AIM

To investigate the influence of type 2 diabetes (T2D) and hyperglycaemia on blood vessels and angiogenic markers in the dental pulp.

METHODOLOGY

Extracted non-carious permanent molar teeth were collected from patients with well-controlled T2D (n = 10) and non-T2D (controls) (n = 10). The pulp was examined qualitatively using haematoxylin and eosin and Van Gieson stains. Immunohistochemistry (IHC) identified the primary receptor for VEGF, VEGFR2, and the endothelial cell marker CD34. Primary human dental pulp cell (hDPC) lines (n = 3) were established from tissue explants and cells were grown in media containing 5.5 mM D-glucose (control), 12.5 mM (prediabetes) and 25 mM (T2D) D-glucose under normoxic conditions for 24, 48 and 72 h. Assays for metabolic activity (PrestoBlue) and cell viability (Crystal Violet staining) assessed the hDPC response to hyperglycaemia. The expression of angiogenic genes VEGFA, KDR, FLT-1, ANGPT1, ANGPT2, TIE1 and TEK were analysed using quantitative real-time polymerase chain reaction. ELISAs were used to quantify the level of expressed protein for VEGFA, ANG1, ANG2, TIE1, and TIE2 in the media. Data analyses were performed using GraphPad Prism and anova tests at p < .05.

RESULTS

Blood vessels in T2D samples had thicker walls and stained strongly for elastin and collagen compared with non-T2D samples. VEGFR2 protein was not seen in any T2D samples but consistently detected in healthy specimens. Culturing healthy cells in high glucose (25 mM) significantly reduced cell viability at 24 h compared to the control (p = .005) and 12.5 mM glucose (p = .001) but the metabolic activity was not greatly affected by glucose and time. VEGFA mRNA and VEGFA protein expression were detected in the hDPCs in the presence of hyperglycaemia over time; however, the primary receptor, VEGFR2/KDR, was not detected. Genes for the ANG1 and ANG2 and their receptors were expressed at all glucose concentrations but hyperglycaemia upregulated ANG2 mRNA. Proteins for all growth factors were detected in the media however proteins for TIE1 and TIE2 receptors were not.

CONCLUSION

T2D and hyperglycaemia may impair the angiogenic response in the pulp similar to other body site. The scarcity of VEGFR2 and increased expression of ANG2 in response to hyperglycaemia suggests that VEGF and ANG-Tie1/Tie2 signalling may be compromised.

Association of Apical Periodontitis with Glycated Hemoglobin Levels and Systemic Inflammatory Markers in Patients with Type 2 Diabetes: A Cross-Sectional Study

INTRODUCTION

This cross-sectional study, as a preliminary part of an ongoing project, aimed to investigate the effect of apical peridontitis (AP) on glycated hemoglobin (HbA1c) and systemic inflammatory markers in diabetic individuals.

METHODS

A total of 280 individuals (140 with type 2 diabetes mellitus [T2DM] and 140 healthy) with and without AP were enrolled. Sixty-four age-, gender-, and body mass index-matched participants each in T2DM with AP group (DAP), T2DM without apical periodontitis (D), systemically healthy controls with apical periodontitis (CAP), and without apical periodontitis (C) groups were evaluated. Radiologic and clinical oral examination was performed for confirming the diagnosis of AP and periapical index scoring (PAI). Blood analyses were carried out for interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, high-sensitivity C-reactive protein (hsCRP), and HbA1c assessment.

RESULTS

Significantly higher levels of IL-1β, TNF-α, and hsCRP were observed in patients with AP in both diabetes and control groups (P < .05). In the diabetes group, AP contributed to significantly raised levels of HbA1c compared with T2DM group patients without AP. After controlling for possible confounders, partial corelation coefficients revealed positive corelation of presence of AP as well as size of the periapical lesion with HbA1c and serum levels of inflammatory markers in both diabetic and healthy individuals. Multivariate linear regression analysis revealed both presence of AP (P < .05) as well as the size of lesion (P < .001) were found to significantly predict the HbA1c levels as well as the levels of IL-1β, IL-6, TNF-α, and hsCRP in both diabetic and non-diabetic individuals.

CONCLUSIONS

These findings suggest that both presence of AP and size of periapical lesion was associated with glycemic control and systemic inflammatory burden in patients with T2DM.

Metabolic syndrome and its effect on immune cells in apical periodontitis- a narrative review

OBJECTIVES

Apical periodontitis (AP) is an inflammatory immune response in periapical tissues caused by microbial infections. Failure of root canal treatment or delayed healing is often due to intracanal or extra-radicular bacteria. However, beyond microbial factors, the patient's systemic health can significantly influence the progression and healing of AP. Metabolic syndrome is a risk factor and it is characterized by a cluster of interconnected metabolic risk factors, including abdominal obesity, hyperlipidemia, hypertension, and hyperglycemia.

MATERIALS AND METHODS

A comprehensive literature review was conducted on apical periodontitis and metabolic syndrome, and their impact on the roles of different immune cell populations.

RESULTS

Both AP and metabolic syndrome are inflammatory diseases that involve complex and interwoven immune responses. The affected immune cells are categorized into the innate (neutrophils, macrophages, and dendritic cells) and adaptive immune systems (T cells and B cells).

CONCLUSIONS

Metabolic diseases and AP are closely correlated, possibly intertwined in a two-way relationship driven by a shared dysregulated immune response.

CLINICAL RELEVANCE

Understanding the pathophysiology and immune mechanisms underlying the two-way relationship between metabolic syndrome and AP can help improve treatment outcomes and enhance the overall well-being of patients with endodontic disease complicated by metabolic syndrome.

Systemic Factors Affecting Prognosis and Outcome of Endodontic Therapy

The successful outcome of endodontic treatment is dependent on the immune response and the reparative potential of the individual. Alteration in the host immune response is a common characteristic shared by both apical periodontitis and systemic diseases. Although infection-induced periapical lesions occur in a localized environment, numerous epidemiologic studies in the last few decades have investigated the potential association between endodontic disease pathogenesis and systemic diseases. The goal of this review is to identify common systematic factors and discuss the effect they may or may not have on the prognosis and outcome of endodontic therapy.

Longitudinal study of endodontic and periapical status of an adult Danish population examined in 2009, 2014, and 2019: a repeated cohort study

OBJECTIVE

To describe endodontic changes in an adult Danish population (C2;2009-2014-2019) and compare them with a similar cohort (C1;1997-2003-2008).

MATERIAL AND METHODS

A randomly selected cohort (C2) with three full-mouth radiographic examinations. The frequencies of teeth, apical periodontitis (AP), root filled teeth, and lost teeth in C2 were compared to a similar cohort (C1) using regression analyses; effect of age, cohort, and period was assessed.

RESULTS

C1 had 330 and C2, 170 participants (mean age, C1: 42.9; C2: 47.3 years, p < .001). The proportion of individuals with no AP was similar in C1 and C2 (p = .46). C2 had a higher proportion of individuals with no root filled teeth (p < .001) and no tooth loss (p = .02) than C1. The proportion of AP and root filled teeth increased with age in both cohorts. C2 had fewer root filled teeth and lost teeth, fewest lost teeth in the youngest age groups.

CONCLUSIONS

In C2, the prevalence of teeth with AP and root fillings increased with age, and few teeth were lost. Change in proportion of AP was similar in two cohorts; fewer root filled teeth and lost teeth in C2. The proportion of lost teeth in C2 showed cohort effect for older age groups.

Impact of chronic diseases on the periapical health of endodontically treated teeth: A systematic review and meta-analysis

Systemic diseases affecting the immune system can influence the body's response time to endodontic treatment, potentially necessitating a longer duration for the complete resolution of existing infections when compared to healthy controls. This systematic review aims to evaluate the association between the presence of chronic diseases and periapical status after endodontic treatment through a systematic and comprehensive assessment of existing literature on this topic. The search strategy covered seven electronic databases and grey literature, encompassing articles published until October 2023. Two reviewers independently assessed potentially eligible studies based on the following criteria: Included were studies involving populations exposed to pre-existing chronic diseases who underwent endodontic treatment in permanent teeth. These studies evaluated periapical health status, making comparisons with healthy individuals. There were no language or publication date restrictions. Additionally, two reviewers independently extracted data regarding the characteristics of the included studies. The risk of bias was assessed using the Joanna Briggs Institute Critical Assessment Checklist. Meta-analysis was conducted using random effects models. The certainty of evidence was assessed using the GRADE tool. Twenty-three studies were included in the synthesis. Patients with diabetes were found to have about half the odds of having periapical health compared to non-diabetic patients (OR = 0.46; 95% CI = 0.30-0.70%; I2 = 58%) in teeth that underwent endodontic treatment. On the other hand, other systemic diseases like HIV, cardiovascular disease, and rheumatoid arthritis did not demonstrate significant differences concerning the outcome. In conclusion, diabetic patients showed a lower likelihood of maintaining periapical health. Conversely, patients with HIV, cardiovascular disease, and rheumatoid arthritis did not exhibit significant differences, although the existing evidence is still considered limited. It is crucial to manage these patients in a multidisciplinary manner to provide appropriate care for this population.

Hyaluronic Acid Treatment of Post-Extraction Tooth Socket Healing in Subjects with Diabetes Mellitus Type 2: A Randomized Split-Mouth Controlled Study

The present study aimed to investigate the effect of HA in improving post-extraction socket healing in subjects with diabetes mellitus (DM) type 2. DM patients requiring bilateral extraction of the homologous teeth were visited at the C.I.R. Dental School, University of Turin. After the extractions, one site was randomly assigned to the test (T) group (postoperative application of HA), while the other site was assigned to the control group (C, no treatment). Patients were then followed after 3, 7, 14, and 21 days. Primary outcomes were the healing index and socket closure. The Mann-Whitney test or the Student's t-test was used for nonparametric or parametric distributed variables. The chi-square test was used if the estimated data in any given cell were >5, otherwise the Fisher test was adopted. A p < 0.05 was considered statistically significant. In total, 36 patients (n = 36) were enrolled in this study for a total of 72 extractions (n = 72). Sockets treated with HA showed significantly (p < 0.05) better healing index values at day 7 (p = 0.01) and at day 14 (p = 0.02) and significantly (p < 0.05) better socket closure values at day 3 (p = 0.04), day 7 (p = 0.001) and day 14 (p = 0.001) compared to the C group. Based on the clinical results, HA seems to be promising in improving the timing and the quality of post-extractive wound healing in DM patients. Further clinical research, as well as histological investigations, are required to confirm the results.

Periapical healing outcome following non-surgical endodontic intervention among diabetic patients: A systematic review conducted according to PRISMA guidelines and the Cochrane handbook for systematic reviews of interventions

Background

Periapical diseases are common dental conditions that require non-surgical endodontic intervention (NEI) for successful treatment. However, the impact of diabetes mellitus (DM) on the periapical healing (PH) outcome in diabetic patients remains somewhat unclear. This review aimed to evaluate the PH outcome following endodontic intervention among DM-afflicted individuals.

Methods

A comprehensive search was conducted across multiple electronic databases to identify relevant studies. Specifically, a set of selection criteria was applied to select studies that assessed PH outcomes in individuals with DM who underwent different treatment protocols. Data extraction and quality assessment were performed following predetermined protocols. The risk of bias (RoB) 2 assessment tool evaluated the quality of the included studies.

Results

A total of 11 studies met the inclusion criteria and were included in the investigation. Four studies showed a higher incidence of apical periodontitis in diabetic individuals compared to controls, and five studies reported reduced healing and success rates in this group. Overall, nine studies have shown that DM has a negative impact on periapical outcomes. This suggests that DM is an important factor in the prognosis of endodontic intervention. The assessment tools used were PAI, PR, SC, and FD analysis. RoB-2 assessed the included studies as having a moderate RoB.

Conclusion

This review provides compelling evidence that DM patients experienced a noticeable negative impact on PH outcomes compared to the control population. These findings highlight the importance of considering the diabetic status of patients when assessing the prognosis of periapical diseases and planning interventions for NEI. Further research is needed to validate these results and explore potential mechanisms underlying the observed associations.

Risk factors associated with the survival of endodontically treated teeth: A retrospective chart review

BACKGROUND

Studies on risk factors affecting tooth retention after endodontic treatment in dental school settings are limited. Understanding these factors is crucial for preserving teeth. The aim of this retrospective study was to evaluate patient- and tooth-level risk factors associated with the survival of endodontically treated teeth.

METHODS

Electronic health records of patients who underwent endodontic treatment at the School of Dental Medicine at the University of Pennsylvania from 2017 through 2020 were analyzed. Patient-level factors included age, sex, American Society of Anesthesiologists Physical Status Classification, smoking history, diabetes status, and amoxicillin allergy. Tooth-level factors included position, presence of restorations, and periodontal conditions with preprosthetic treatments.

RESULTS

The results of this study indicate that the patient-level factors significantly associated with tooth retention included age, sex, American Society of Anesthesiologists Physical Classification Status, and amoxicillin allergy. Tooth-level factors such as core buildup, full-coverage crown, healthy periodontium, and scaling and root planing were also associated with higher survival rates. Mandibular premolars had higher survival rates than mandibular molars.

CONCLUSIONS

This investigation revealed that the tooth retention rate of endodontically treated teeth was 96.2% after initial root canal treatment, 92.4% for nonsurgical re-treatment, and 97.8% for surgical re-treatment.

PRACTICAL IMPLICATIONS

The tooth retention of the endodontic treatment was associated with healthy periodontium, tooth structure, tooth position, tooth restoration, and the patient's overall health.

Diabetes Mellitus Increases the Risk of Apical Periodontitis in Endodontically-Treated Teeth: A Meta-Analysis from 15 Studies

INTRODUCTION

At present, the incidence of diabetes mellitus (DM) is gradually increasing globally. In clinical practice, many patients with diabetes with apical periodontitis (AP) have poor and slow healing of periapical lesions. However, the potential relationship between the 2 is still unclear and controversial. The consensus is that DM can be deemed a risk factor for AP in endodontically-treated teeth. Therefore, we pooled existing studies and carried out a meta-analysis to explore the potential association between the 2.

METHODS

Studies that met the inclusion criteria were selected from the database, and relevant data were extracted. Stata SE 17.0 software was used to analyze the relevant data, and the Newcastle-Ottawa Scale was used to assess the literature's quality. The pooled odds ratio (OR) with a 95% confidence interval (CI) was used to determine the strength of the association between DM and the prevalence of AP after root canal treatment (RCT).

RESULTS

After searching, 262 relevant studies were retrieved, fifteen of which met the inclusion criteria. A total of 1087 patients with 2226 teeth were included in this meta-analysis. According to the findings, diabetics showed a higher prevalence of AP after RCT than controls at the tooth level (OR = 1.51, 95% CI = 1.22-1.87, P < .01). At the patient level, DM increased the probability of developing AP in RCT teeth more than 3 times (OR = 3.38, 95% CI = 1.65-6.93, P < .01). Additionally, subgroup analysis was performed by blood glucose status, preoperative AP, and study design. Except for the status of blood glucose, the results were significant in the other 2 groups (P < .05).

CONCLUSIONS

Available scientific evidence suggests that DM may increase the risk of AP in endodontically-treated teeth. In teeth with preoperative AP, DM might promote the development of AP.

Bacterial quantity and interleukin-17 expression in necrotic teeth with apical periodontitis from type II diabetic patients

Diabetes mellitus (DM) increases the susceptibility to infection. A plausible association between apical periodontitis (AP) and DM has been reported, but the underlying mechanism is not yet elucidated.

AIM

To investigate the bacterial quantity and the expression of interleukin-17 (IL-17) in necrotic teeth with AP in type 2 DM (T2DM), pre-diabetic and non-diabetic control patients.

METHODOLOGY

In all, 65 patients with necrotic pulp and AP [periapical index (PAI) scores ≥3] were included. The age, gender, medical history and medications list, including metformin and statin intake, were recorded. Glycated haemoglobin (HbA1c) was analysed, and the patients were divided into three groups: T2DM (n = 20), pre-diabetics (n = 23) and non-diabetic (n = 22). Bacterial samples (S1) were collected by file and paper points. Bacterial DNA was isolated and quantified using 16S ribosomal RNA gene-targeted quantitative real-time polymerase chain reaction (qPCR). For IL-17 expression, (S2) samples were collected from the periapical tissue fluid using paper points passing through the apical foramen. The IL-17 total RNA was extracted, and reverse transcription (RT-qPCR) analysis was performed. Comparisons between the three study groups were conducted using one-way anova and Kruskal-Wallis test to explore the relationship between bacterial cell counts and IL-17 expression in each group.

RESULTS

The distributions of PAI scores were equivalent among the groups, p = .289. T2DM patients had higher bacterial counts and IL-17 expression than other groups, but these differences were not statistically significant, p = .613 and p = .281, respectively. T2DM patients taking statin appear to have lower bacterial cell count than those who do not take statin, approaching the significance level, p = .056.

CONCLUSION

T2DM patients had a non-significant higher bacterial quantity and IL-17 expression compared to pre-diabetic and healthy controls. Although these findings indicate a weak association, it may impact the clinical outcome of endodontic diseases in diabetic patients.

The Incidence of Retrograde Peri-Implantitis in a Single University Dental Hospital Training Center: A Retrospective Analysis

Background and objective: Retrograde peri-implantitis (RPI) is a periapical radiolucent lesion developed around the implant apex. This study aimed to investigate the Incidence of RPI in a single university dental hospital training center. Materials and Methods: All records of patients who received single Implants between 2016-2020 were screened. For cases that met inclusion criteria, clinical and radiographic data were analyzed. Results: A total of 215 were included and categorized as follows, Category A: implants were placed next to endodontically treated teeth (n = 58, 27%); category B, implants placed at the sites with previous endodontic involvement within 6 months of tooth extraction (n = 25, 11.6%); Category AB: implants placed at sites that fulfill the criteria of groups A and B (n = 18, 8.4%); and Category C: Implants that were placed next to vital teeth and at a site with no previous endodontic treatment or a site that was allowed to heal for more than six (n = 114, 53%). Categories A, B and AB served as the endodontically involved (EI) group, while category C served as non- endodontically involved (NEI) group. Only two sites (0.9%) were confirmed as RPI, both from group A (3.4%). Comparing all groups studied showed no statistically significant difference in RPI incidence. Conclusions: The incidence of RPI is low; however, endodontically treated teeth with periapical lesions (PALs) next to an implant site could contribute to RPI.

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.

Outcomes reporting in systematic reviews on non-surgical root canal treatment: A scoping review for the development of a core outcome set

BACKGROUND

Studies related to non-surgical root canal treatment are amongst the most frequently performed clinical studies in endodontics. However, heterogeneity in reporting outcomes and lack of standardization is a significant challenge to evidence synthesis and guideline development.

OBJECTIVES

The aims of the present scoping review were to (a) identify outcomes reported in systematic reviews evaluating non-surgical root canal treatment; (b) identify how and when the reported outcomes were measured; (c) assess possible selective reporting bias in the included studies. The information obtained in this study should inform the development of a core outcome set (COS) for non-surgical root canal treatment.

METHODOLOGY

Structured literature searches were performed to identify systematic reviews on non-surgical root canal treatments published in English between January 1990 and December 2020. Two reviewers undertook study selection and data extraction. Outcomes were categorized according to a healthcare taxonomy into five core areas (survival, clinical/physiological changes, life impact, resource use, and adverse events). The outcome measurement tools and length of follow-up were recorded.

RESULTS

Seventy-five systematic reviews were included, of which 40 included meta-analyses. Most reviews reported on physiological and clinical outcomes, primarily pain and/or radiographic assessment of periapical status, and a variety of measurement tools and scales were used. Few reviews focused on tooth survival, life impact, resources, and adverse events. The heterogeneity amongst the reviews was large on all parameters. Less than 40% of the reviews assessed the risk of selective reporting.

DISCUSSION

Overall aims of the included reviews were highly heterogenic; thus, outcomes and how they were measured also varied considerably. Patient-centred outcomes and the use of resources were rarely reported on.

CONCLUSIONS

Most studies reported on physiological and clinical outcomes, in particular pain and/or radiographic healing. Measurement tools, scales, thresholds, and follow-up periods varied greatly within each outcome, making comparison across studies complicated. Less than 40% of the reviews assessed risk of selective reporting; thus, selective bias could not be ruled out. The presented information on reported outcomes, measurement tools and scales, and length of follow-up may guide the planning of future research and inform the development of a COS for non-surgical root canal treatment.

Revisiting the role of IL-1 signaling in the development of apical periodontitis

Apical periodontitis (AP) develops as a result of an immune response to pulpal bacterial infection, and various cytokines are involved in the pathogenesis of AP, with Interleukin (IL)-1 being considered a key cytokine. The role of IL-1 in the pathogenesis of AP has been well studied. It is known that IL-1 expression in periapical lesions correlates closely with the development of AP. IL-1 is a potent bone-resorptive cytokine that induces osteoclast formation and activation. Hence, inhibiting its signaling with IL-1 receptor antagonist (IL-1RA) results in a reduction in periapical lesion size. On the other hand, IL-1 is also a central cytokine that combats bacterial infection by activating innate immune responses. Therefore, a complete loss of IL-1 signaling leads to a failure to limit bacterial dissemination and consequently exacerbates AP. In vivo, IL-1 expression is tightly regulated and its signaling is modulated to optimize the immune response. Obesity causes systemic low-grade chronic inflammation and increases the risk of cardiovascular, renal, and other disorders. In experimentally induced AP, obesity significantly increases periapical bone loss, albeit the underlying mechanism remains unclear. Recent technological innovations have enabled more comprehensive and detailed analyses than previously, leading to new insights into the role of IL-1RA in regulating IL-1 signaling, and modulating apical lesion progression in obesity. In this review, we provide a brief overview of the function of IL-1 in AP development, with special emphasis on the latest findings in normal weight and obese states.

Type 2 diabetes and the clinically normal pulp - An in-vitro study

Aim

The aim of this study was to investigate the effect of type 2 diabetes (T2D) on clinically normal dental pulp tissue by using special stains and immunohistochemistry (IHC) to determine the morphology of the coronal pulp and distribution of immune markers in non‐T2D and T2D groups.

Methodology

Ethics approval for this in vitro pilot study was obtained from the University of Otago Human Ethics Committee (16/069). Twenty extracted permanent molar teeth diagnosed as having clinically normal pulp status were collected. Ten teeth were from participants with well‐controlled T2D and ten from participants without diabetes (non‐T2D). Each tooth was sectioned transversely at the cemento‐enamel junction before the crowns were decalcified and embedded in paraffin. Sections were stained with haematoxylin and eosin, Massons trichrome, and van Gieson stains for histological and morphological evaluation. IHC using anti‐CD4, anti‐CD68 and anti‐CD83 and anti‐IL1β, anti‐IL6, anti‐IL17, anti‐TNF‐α, anti‐TLR2, anti‐TLR4 and anti‐FOXP3 identified proteins of interest. Qualitative and semi‐quantitative analyses evaluated the morphology of the dental pulp and protein expression. Data analyses were performed with GraphPad Prism, using Student's t‐test and multiple regression using SPSS at p < .05.

Results

Special stains demonstrated morphological differences in the T2D dental pulp compared with non‐T2D. Qualitative analysis indicated that the pulp in the T2D samples was consistently less cellular, less vascular, showed evidence of thickened blood vessel walls, increased pulp calcification and collagen deposition. Semi‐quantitative analysis of IHC samples showed the T2D pulp had significantly increased expression of macrophage and dendritic cell markers CD68 (p < .001) and CD83 (p = .04), and there was significantly greater expression of inflammatory cytokines IL1β (p = .01), IL6 (p < .0001), IL17 (p < .0001) and TNF‐α (p = .01). T2D samples showed a significant increase in markers of innate inflammation, TLR2 (p < .001) and TLR4 (p < .001) and decreased expression of regulatory T‐cell marker, FOXP3 (p = .01). Multiple regression showed that age‐corrected differences were statistically significant.

Conclusion

Preliminary findings suggest that T2D may exert a similar response in the pulp to complications in other body sites. Hyperglycaemia is associated with changes in the morphology of the clinically normal dental pulp with altered immune cell and cytokine expression.

Association between patient-, tooth- and treatment-level factors and root canal treatment failure: A retrospective longitudinal and machine learning study

OBJECTIVES

We aimed to assess patient-, tooth- and treatment-level covariates on the failure of root canal treatments (RT) and to predict failure using machine learning (ML).

METHODS

Teeth receiving RT at one large university hospital from 2016-2020 with a minimum follow-up of ≥6 months were included. Failure compromised absent radiographic healing and/or the presence of clinical symptoms. Covariates were selected on tooth-, treatment- and patient-level. We used logistic regression (logR) to determine associations in the full dataset, and logR as well as more advanced ML (random forests (RF), gradient boosting machine (GBM) and extremely gradient boosting (XGB)) for predictive modeling (area-under-the-receiver operating characteristic-curve (ROCAUC)) and testing on a separate test dataset.

RESULTS

458 patients (female/male 47.2/52.8%) with 591 permanent teeth were included (overall success rate 79.5%). In logR, tooth-level covariates showed strong associations with failure: Alveolar bone loss 66-100% (ABL, OR 6.48, 95% CI [2.86; 14.89], p<0.001); Periapical index (PAI) score≥4 (OR 4.59, [2.44; 8.79], p<0.001); ABL 33-66% (OR 2.59 [1.49; 4.49], p<0.001); PAI=3 (OR 2.45, [1.43; 4.34], p<0.01); Treatment type "retreatment" (OR 1.77, [1.01; 2.86], p<0.01). On patient level only smoking (OR 2.05, [1.18; 3.53], p<0.05) was significantly associated with risk of failure. For predictive modelling, the predictive power of all models was limited (ROCAUC: logR 0.63, [0.53, 0.73]; GBM 0.59, [0.50, 0.68]; RF 0.59, [0.50, 0.68]; XGB 0.60, [0.50, 0.70]).

CONCLUSIONS

Failure of RT was associated mainly with tooth-level covariates. Predicting failure was only limitedly possible, also with more complex ML.

CLINICAL SIGNIFICANCE

Identifying specific risk factors for failure of RT and predicting the outcome of RT is relevant for treatment planning and informed shared decision-making. The present study found tooth-level factors to be associated with failure. Notably, predicting failure was only limitedly possible.

Oral Osteomicrobiology: The Role of Oral Microbiota in Alveolar Bone Homeostasis

Osteomicrobiology is a new research field in which the aim is to explore the role of microbiota in bone homeostasis. The alveolar bone is that part of the maxilla and mandible that supports the teeth. It is now evident that naturally occurring alveolar bone loss is considerably stunted in germ-free mice compared with specific-pathogen-free mice. Recently, the roles of oral microbiota in modulating host defense systems and alveolar bone homeostasis have attracted increasing attention. Moreover, the mechanistic understanding of oral microbiota in mediating alveolar bone remodeling processes is undergoing rapid progress due to the advancement in technology. In this review, to provide insight into the role of oral microbiota in alveolar bone homeostasis, we introduced the term “oral osteomicrobiology.” We discussed regulation of alveolar bone development and bone loss by oral microbiota under physiological and pathological conditions. We also focused on the signaling pathways involved in oral osteomicrobiology and discussed the bridging role of osteoimmunity and influencing factors in this process. Finally, the critical techniques for osteomicrobiological investigations were introduced.

Association between Pulpal-Periapical Pathology and Autoimmune Diseases: A Systematic Review

Several studies have linked apical periodontitis and systemic diseases. The aim of this study is to present a systematic review of the available literature investigating whether there is an association between pulpal-periapical pathology and autoimmune disease. The review was conducted following the PRISMA statement. A literature search was performed in five databases. Studies involving patients with pulpal-periapical pathology and autoimmune diseases were included in the review. Based on the PICO model, the research question aimed to assess whether there is an increased risk of developing pulpal-periapical pathology in patients with autoimmune disease. Article selection, data extraction, and quality assessment were performed using an adapted version of the STROBE guidelines. A total of seven studies were included in our review. The types of articles were five case-control and two cross-sectional studies. Periapical pathologies were associated to three autoimmune diseases (diabetes mellitus I, rheumatoid arthritis, and inflammatory bowel disease). Among the included studies, four show a low risk of bias, while three present a moderate risk. There could be an association between apical periodontitis and autoimmune diseases, although most studies report statistically non-significant associations.

Evolution of endodontic medicine: a critical narrative review of the interrelationship between endodontics and systemic pathological conditions

Endodontics has gained emphasis in the scientific community in recent years due to the increase in clinical and in animal models studies focused on endodontic medicine, which aims to evaluate the interrelationship between systemic and periapical tissues pathological conditions. These studies have shown that systemic changes can boost the pathogenesis of endodontic infection, favoring its development and progression. A contrary relationship is reported in numerous studies that affirm the potential of endodontic infection to trigger systemic damage and may lead to the worsening of pre-existing pathologies. Recently, the potential of filling materials to develop systemic changes such as neurological alterations had been evaluated, also showing that systemic diseases can negatively influence tissue responses to filling materials after endodontic treatment. Despite advances in endodontic medicine studies, there are still gaps in knowledge on the mechanisms of interactions between apical periodontitis (AP) and systemic diseases and much research to be done. In this sense, this critical narrative literature review aimed to show the evolution of studies in endodontic medicine to help the endodontist to know the role of systemic diseases in the pathogenesis of AP and the possible interference in the repair of periapical tissues after endodontic treatment, as well as to evidence the systemic complications that can be triggered or aggravated in the presence of endodontic infection.

Evaluation of the efficiency of antibiotics in treating adult patients with symptomatic apical periodontitis: A protocol for systematic review and meta-analysis

BACKGROUND

When a person feels dental pain, it brings great discomfort and damages the quality of life. Symptomatic apical periodontitis is identified as the most frequent cause that triggers dental pain. Symptomatic apical periodontitis arises from an infection or inflammation in the pulpless root canal structure. According to clinical guidelines, the primary form of therapy for such teeth entails removing the inflammation or infection source through local surgical procedures. Presently, systemic antibiotics are recommended only for cases where there is clear indication of an infectious spread or a systemic involvement. Therefore, this study aims to assess the efficacy and level of safety of using antibiotics to treat adult symptomatic apical periodontitis patients.

METHODS

The present protocol study will conduct a search on electronic databases to look for randomized controlled trials (RCTs) that have evaluated the effectiveness and safety of antibiotics when used to treat adult patients with symptomatic apical periodontitis. The databases will be search from their beginning to April 2021. The search is not bound by publication status or language restrictions. The following databases will be searched: Web of Science, PubMed, the Cochrane Library, Chinese National Knowledge Infrastructure, and EMBASE. This study will employ ZETOC Conference Proceedings and OpenGrey to identify potential grey literature. Afterwards, 2 independent authors will select the studies, extract data from the studies, and conduct a risk assessment to check for bias. All discrepancies between the authors will be resolute via discussion involving a third independent author. The data synthesis and statistical analysis of this study will be done with the RevMan software (Version: 5.3).

RESULTS

The present protocol report will provide high-quality evidence related to the efficacy and level of safety when using antibiotics to treat mature symptomatic apical periodontitis patients.

CONCLUSION

The outcomes of the present study will update the evidence available for assessing the efficacy and safeness of using antibiotics to treat mature symptomatic apical periodontitis patients.

ETHICS AND DISSEMINATION

This study does not require an ethical approval since individual patient data is not included in any form.

REGISTRATION NUMBER

DOI 10.17605/OSF.IO/CVP8 M (https://osf.io/cvp8m/).