Chemomechanical preparation influences the microbial community and the levels of LPS, LTA and cytokines in combined endodontic-periodontal lesions: A clinical study

Teeth with vital pulps and stage III periodontitis unresponsive to therapy exhibit a pulpal inflammatory profile similar to symptomatic irreversible pulpitis

AIM

The aim of this study is to investigate the expression of inflammatory biomarkers (TNF-α, IL-10, IL-1β) and the pulpitis-associated miRNA (miR-30a-5p and miR-128-3p) in pulp tissue samples from unrestored teeth with a vital normal pulp (NP), teeth with symptomatic irreversible pulpitis (IP) and in unrestored teeth with periodontal disease, unresponsive to periodontal therapy, and a vital pulp (EP).

METHODOLOGY

Thirty patients were included in this observational study (10 teeth with NP, 10 teeth with IP, 10 teeth with EP). Dental pulp tissues samples were collected from patients during root canal treatment (RCT). RNA was extracted and qRT-PCR of target genes (tumour necrosis factor [TNF]-α, interleukin [IL]-1β, IL-10) and miRNAs (has-miR-30a-5p, has-miR-128-3p) performed to assess the expression profile. Fold-change in expression was calculated using the formula 2-(ΔCt(Exp)-ΔCt(Ctrl)). One-way anova with post-hoc Tukey's was used to determine significant differences between groups. The significance level was set at 5% (p < .05). All teeth were also followed up clinically for 1 year and evaluated for a range of endodontic and periodontal-related outcomes.

RESULTS

All investigated genes significantly increased in expression and miRNAs significantly decreased in expression in the IP and EP groups compared with the NP group (p < .05). With regards to TNF-α and IL-1β there were no significant differences in expression between the IP and EP groups (p > .05), whereas IL-10 expression levels were significantly reduced in the EP compared with the IP group (p < .05). Both miR-30a-5p and miR-128-3p showed significantly reduced expression in both IP and EP lesions, compared with NP (p < .05); however, no significant differences in miRNA expression were observed between IP and EP groups (p > .05). One year after root canal treatment and periodontal maintenance, tooth mobility and probing depth were significantly reduced in the EP group (p < .05).

CONCLUSION

Pulp tissues from teeth with IP and EP presented similar levels of altered inflammatory markers compared with NP. TNF-α, IL-10, IL-1β cytokines and miRNAs (miR-30a-5p and miR-128-3p) are potential objective biomarkers to indicate pulpal inflammatory status, aiding diagnosis and directing clinical decision-making. RCT may be beneficial to improve stage III periodontitis unresponsive to non-surgical periodontal treatment, but further research is required.

A Methodological Study on Microbial In Vivo Sampling Methods of Root Canal Microbiota for Next-Generation Gene Sequencing Analysis

INTRODUCTION

The aim was to evaluate the suitability of paper points or endodontic nickel-titanium files to sample microorganisms for in vivo investigation of endodontic microbiota by 16S ribosomal DNA (rDNA) sequencing.

METHODS

Forty-five patients presenting clinical and radiological signs of apical periodontitis were recruited for sampling, giving their written informed consent. Glide paths were assessed using C-Pilot Files and K-Files under electronic root canal length control under aseptic conditions. Microbial samples were taken from 84 root canals in duplicate, the first sample with a sterile paper point (size 15), the second with a sterile file (size 20/.06). After DNA extraction, the hypervariable region V4 of the bacterial 16 S rRNA gene was amplified and sequenced (Illumina MiSeq). Sequencing data were trimmed with Cutadapt and exact amplicon sequence variants generated by DADA2. Taxonomy was assigned based on the Human Oral Microbiome Database (eHOMD). Statistical analysis of diversity parameters comprised Wilcoxon signed-rank tests and permutational analysis of variance (PERMANOVA). Compositional differences were evaluated by differential abundance analysis (DESeq2). Microbial contamination during the sampling process and analysis were evaluated.

RESULTS

Concerning alpha diversity, richness and dissimilarity differed nonsignificantly between paper point and instrument samples (P > .05), whereas a significant difference was observed in the Shannon index (P < .05). Regarding beta diversity, paper point and instrument samples presented with similar microbial community compositions (P = 1.0, PERMANOVA). Paper point controls contained significantly higher proportions of Pseudomonadales (P < .05).

CONCLUSIONS

Paper point and endodontic instrument sampling generate valid specimens for 16S rDNA community profiling. Endodontic instrument sampling is easier to execute and, therefore, could be the technique of choice.

Factors that influence the outcome of pulpotomy in permanent teeth

The promotion of minimally invasive treatments focussed on the maintenance of pulp vitality has become a priority area in Endodontics. These vital pulp treatments (VPT) include partial and full pulpotomy, during which diseased coronal pulp tissue is removed prior to placement of a capping biomaterial and restoration. Traditionally, pulpotomies were confined to the treatment of carious primary and traumatized permanent teeth. However, these treatments have now been proposed as definitive solutions for cariously exposed permanent teeth with mild symptoms or even symptoms indicative of irreversible disease. Until recently, it was recommended that carious exposure of mature permanent teeth be managed by root canal treatment. The promotion of pulpotomy as an alternative treatment has opened up a wave of laboratory and clinical research aimed at improving therapies or evaluating clinical outcomes. In modern evidence-based endodontics, it is imperative that the outcomes of both partial and full pulpotomy are considered and important prognostic factors identified, so that improvements can be made to aid clinical decision-making and to direct new research. In this narrative review, the outcomes of partial and full pulpotomy are discussed, before analysis of patient, intraoperative and postoperative factors that influence the outcome of the pulpotomy procedure. The review highlights that although partial and full pulpotomy for the treatment of even pulpal disease are highly successful procedures, this is based on low-quality evidence with a lack of prospective, comparative trials investigating potential prognostic factors. Based on current evidence, it appears that age, gender, tooth type, root development and intraoperative pulpal haemorrhage do not impact significantly on pulpotomy outcome, whilst others such as caries depth, inflammatory status of the pulp, capping material, level of inflammatory pulpal-biomarkers and the final restoration integrity do. Other factors, including the influence of exposure type, periodontal condition, pulpal lavage, magnification, operator experience, isolation of the operating field and type of pulpotomy, require further experimental investigation before definitive conclusions can be made relating to the success of the pulpotomy procedure. Finally, there is not only a need for future well-designed prospective research addressing these issues but also a widening of our understanding of outcome to include patient-reported as well as clinician-reported outcomes.

Time-lapse between periodontal regeneration surgery and root canal therapy in sever combined periodontal-endodontic lesions

Objective

The purpose of this study was to evaluate the time-lapse of periodontal regeneration surgery of combined periodontal-endodontic lesions (PEL) after root canal therapy (RCT) to guide the clinical treatment.

Methods

26 patients (28 teeth) with severe combined PEL were equally divided into 4 groups (n = 7); the control group included patients who underwent periodontal regeneration surgery with no prior RCT and the remaining three experimental groups including patients who received periodontal regeneration surgery post-RCT either immediately or after 3 and 6 months. The probing depth, clinical attachment loss, and periodontal bone density were measured before or after 3, 6, and 12 months post-RCT, respectively.

Results

Periodontal regeneration surgery could improve the PD (Probing Depth), CAL (Clinical Attachment Loss), BD (Bone Mineral Density) values irrespective of whether the RCT was performed within 12 months or not. However, obviously improved PD, CAL and BD were observed when surgery was performed post-RCT. The time lapse between RCT and periodontal regeneration surgery had no obvious effects on the periodontal index in 3 months after the surgery. Moreover, these periodontal indexes tend to stabilize in 3 to 6 months after the surgery with no significant differences.

Conclusion

Although there were no obvious impacts of time lapse between RCT and periodontal regeneration surgery on the severe PEL, an earlier periodontal surgery might contribute to the healing of periodontal lesions.

Effect of antimicrobial photodynamic therapy on the reduction of bacteria and virulence factors in teeth with primary endodontic infection

OBJECTIVE

To evaluate the effectiveness of supplemental photodynamic therapy for improving the bacterial removal and the levels of lipopolysaccharide (LPS) and lipoteichoic acid (LTA) by conducting a clinical trial.

METHODOLOGY

Twenty-four root canals with pulp necrosis and periapical lesion were selected and randomly divided into conventional group using endodontic treatment with chemo-mechanical preparation (CMP) alone (n = 12) and a group using antimicrobial photodynamic therapy (aPDT) after CMP (n = 12). The samples were collected before and after CMP (conventional group) and after photodynamic therapy (aPDT group). A photosensitizer (0.005% methylene blue) was applied to the root canal for 3 minutes after CMP, whereas aPDT was performed by using a red laser with a power of 30Mw and energy density of 9J/cm² for 90 s per root canal. Culture technique was performed to determine the bacterial colony forming units. LPS and LTA levels were quantified by using limulus amoebocyte lysate (LAL) assay and enzyme-linked immunosorbent assay (ELISA), respectively.

RESULTS

All samples showed growth of viable bacteria on Fastidious Anaerobe Agar (FAA), with an average of 5.19 × 10⁵ CFU/ mL. CMP was effective in decreasing viable bacteria (p < 0.05), whereas there was a significant decrease (p < 0.05) in the samples treated with aPDT compared to those submitted to CMP. LPS and LTA were detected in all initial samples, with mean values of 20.561 EU/mL and 430.91 pg/mL, respectively. Both CMP and aPDT groups significantly decreased the levels of LPS and LTA (p < 0.05), with a statistical difference between the groups regarding aPDT (p < 0.05).

CONCLUSION

Photodynamic therapy as an adjunct to CMP proved to be effective in improving root canal disinfection and reducing the LPS and LTA levels in teeth with primary endodontic infection.

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.