Comparison of the effectiveness of single- and multiple-sessions disinfection protocols against endotoxins in root canal infections: systematic review and meta-analysis

Reduced C-reactive protein levels after root canal treatment in clinically healthy young apical periodontitis individuals at cardiovascular risk. A prospective study

AIM

To determine the systemic inflammatory burden, including hsCRP and its monomeric forms, in patients with apical lesions of endodontic origin treated with root canal treatment (RCT).

METHODOLOGY

Prospective pre-/post-study. Apical periodontitis (AP) individuals aged 16-40 were included (N = 29). Individuals received RCT and were followed at 1 and 6 months. Fasting blood samples were obtained. Apical lesions of endodontic origin (ALEO) diameter (mm), and periapical index (PAI), were recorded. The serum concentrations of total hsCRP were determined by turbidimetry. Tumour necrosis factor (TNF)-α, interleukin (IL)-6, IL-10, IL-1β, and soluble (s) E-selectin were assessed by Multiplex assay. Additionally, mCRP forms were determined in the serum of AP patients with a baseline moderate to high cardiovascular risk based on hsCRP stratification (hsCRP ≥1 mg/L) by immunowestern blot (n = 15). Also, CRP isoforms were explored in ALEOs from AP individuals (n = 4). Data were analysed with StataV16.

RESULTS

Periapical index and ALEO sizes were reduced at both follow-up visits after RCT (p < .05). Serum levels of TNF-α, IL-6, IL-10, IL-1β, and sE-selectin did not show significant differences. CRP was borderline reduced at 1 month (p = .04); however, in AP individuals at cardiovascular risk (hsCRP ≥ 1 mg/L), hsCRP and its monomeric isoform significantly decreased at 1 and 6 months (p < .05).

CONCLUSIONS

High-sensitivity CRP and mCRP are reduced after RCT in AP individuals at cardiovascular risk.

Clinical efficacy of endodontic protocols on reducing cultivable bacteria and endotoxin in infected root canal in patients submitted to head and neck radiotherapy: a randomised clinical trial

OBJECTIVES

Assess the efficacy of biomechanical preparation using a reciprocating system followed by final irrigation protocols, then intracanal medication, on reducing endotoxins and cultivable bacteria of infected teeth in irradiated patients.

MATERIALS AND METHODS

Twenty-two infected single-rooted canals in patients submitted to head and neck radiotherapy were prepared by reciprocating motion and 2.5% NaOCl. Patients were randomly divided into two groups of 11 patients before the final irrigation protocol: apical positive pressure (APP) or passive ultrasonic activation (PUA). Both groups were treated in two sessions, using Ca(OH)2 as intracanal medication for 14 days. Root canal content sampling was performed after canal access (S1), after biomechanical preparation plus the irrigation protocol (S2), and after intracanal medication (S3). Chromogenic limulus amoebocyte lysate assay measured endotoxin levels (EU/mL), and bacterial load was determined by culture techniques (CFU/mL).

RESULTS

Treatment protocols reduced bacterial counts after S2 in both groups (p = 0.01). S3 differed from S1 (p = 0.01), but not from S2 (p = 0.4). Endotoxin levels were reduced in both groups after S2 (P = 0.03) and were lower in S3 than in S2, with significant differences in the APP group (p = 0.03).

CONCLUSIONS

Biomechanical preparation using a reciprocating system and 2.5% NaOCl in irradiated teeth, followed by the irrigation protocol (APP or PUA), demonstrated efficacy in reducing endodontic contaminants. Ca(OH)2 as intracanal medication should be performed in irradiated patients with infected root canals.

CLINICAL RELEVANCE

This clinical study demonstrated that endodontic treatment in irradiated patients is efficacious at reducing bacterial load and endotoxin levels.

Temporary Root Canal Obturation with a Calcium Hydroxide-Based Dressing: A Randomized Controlled Clinical Trial

Successful bacterial inactivation or elimination is essential for successful outcomes in endodontics. This study investigated the efficacy of a calcium hydroxide paste (Ca(OH)2) as a temporary medical dressing for 1 week after chemomechanical root canal treatment (CMRCT). Microbiological samples from 26 patients were collected after endodontic emergency treatment as follows: (1) removal of the provisional filling material; (2) CMRCT; (3) irrigation with sodium hypochlorite I (3%); (4) medicinal insertion of Ca(OH)2; and (5) irrigation with sodium hypochlorite II (3%). A microbiological examination was carried out after the specimens had been taken from the root canals via saline and sterile paper points. CMRCT resulted in a significant reduction in total bacterial load (TBL) in the root canal (p < 0.05). Additional irrigation (3) resulted in a further significant reduction in TBL (p < 0.05). In contrast, Ca(OH)2 medication did not prevent the bacterial load from returning to the previous level immediately after CMRCT, but did not increase above that level either (p < 0.05). However, the increase in TBL was significant (p < 0.05) in comparison with the disinfection groups (I/II). Administration of Ca(OH)2 for 1 week shows that in combination with an additional disinfection procedure, an increase in TBL must be expected, but not above the level of conditions after CMRCT.

Biocompatibility, Biomineralization and Induction of Collagen Maturation with the Use of Calcium Hydroxide and Iodoform Intracanal Dressing

Biocompatibility and biomineralization of root canal dressings are important requirements for periapical healing. This study evaluated the inflammatory response, biomineralization and tissue repair by collagen fiber maturation in the subcutaneous tissue of rats. Eighteen Wistar rats (n = 6) received subcutaneous implants: calcium hydroxide + propylene glycol [CH+P], calcium hydroxide + propylene glycol + iodoform [CH+P+I], iodoform + carbowax [I+Cwax] and carbowax [Cwax]. Extra empty tubes were used as a control [C]. After 7, 15 and 30 days, the implants were removed with surrounding tissue for staining of hematoxylin-eosin, Von Kossa, picrosirius red and without staining for analysis under polarized light. Results were analyzed via Kruskal-Wallis followed by Dunn testing for nonparametric data and ANOVA followed by a Tukey post hoc test for parametric data (p < 5%). At 7 days, all groups showed a moderate inflammatory reaction and thick fibrous capsule, except the [Cwax] group, with a severe inflammatory infiltrate (p < 0.05). After 15 days, all groups but control had a decrease in inflammatory response. At 30 days, all groups presented a mild reaction and thin fibrous capsule (p > 0.05). Only groups containing calcium hydroxide were found to be positive using Von Kossa staining and polarized light in all periods. At 7 days, all groups showed a higher proportion of immature fibers. At 15 days, the [CH+P] and [Cwax] groups increased their proportion of mature/immature fibers. At 30 days, only the [CH+P] group presented a significant prevalence of mature collagen fibers (p < 0.05). All groups showed biocompatibility, but only groups containing calcium hydroxide induced biomineralization. The addition of iodoform delayed tissue healing.

Impact of N-acetylcysteine (NAC) and calcium hydroxide intracanal medications in primary endodontic infection: a randomized clinical trial

OBJECTIVES

This RCT investigated the impact of N-acetylcysteine (NAC) and calcium hydroxide [Ca(OH)₂] intracanal medications (ICMs) in primary endodontic infection with apical periodontitis (PEIAP).

MATERIALS AND METHODS

Thirty-six teeth with PEIAP were randomly divided into groups according to the ICM: NAC, Ca(OH)₂ + saline solution (SSL), and Ca(OH)₂ + 2% chlorhexidine-gel (2% CHX-gel) (all, n = 12). Root canal samples (RCSs) were collected before (s1) and after instrumentation (s2) and after 14 days of ICM (s3). Chemomechanical preparation (CMP) was performed with a Reciproc file and 2.5% NaOCl. Checkerboard DNA-DNA hybridization was used to assess 40 target bacteria species.

RESULTS

At s1, bacterial DNA was detected in 100% of RCSs (36/36). All 40 bacterial species were found in PEIAP. The mean number of species per RCS was 17.92 ± 13.18. The most frequent bacteria were S. mitis (65%), E. nodatum (63%), E. faecalis (63%), F. nucl sp vicentii (58%), T. forsythia (58%), and F. periodonticum (56%). CMP reduced the mean number of species per RCS to 6.8 ± 2.36 (p < 0.05). At s3, the intragroup analysis revealed a broader antimicrobial activity for Ca (OH)₂ + 2% CHX-gel and NAC than Ca(OH)₂ + SSL (p < 0.05). NAC eliminated 8/12 bacteria species resistant to both Ca (OH)₂ ICMs, including P. micra, P. nigrescens, T. denticola, A. israelii, P. endodontalis, P. acnes, C. ochracea, and E. corrodens.

CONCLUSIONS

Ca (OH)2 + 2% chlorhexidine gel (2% CHX gel) showed a greater bacterial elimination over the number of bacterial species; however, NAC eliminated 8/12 bacteria species resistant to both Ca (OH)2 ICMs (RBR-3xbnnn).

CLINICAL RELEVANCE

The use of intracanal medication with a broad antimicrobial activity can optimize root canal disinfection. Ca(OH)₂ + 2% CHX gel and NAC showed a broader antimicrobial activity than Ca(OH)₂ + SSL against endodontic pathogens in primary root canal infection.

TRIAL REGISTRATION

Brazilian Registry of Clinical Trials (REBEC), No. RBR-3xbnnn.

Impact of N-acetylcysteine (NAC) and calcium hydroxide intracanal medications in primary endodontic infection: a randomized clinical trial

OBJECTIVES

This RCT investigated the impact of N-acetylcysteine (NAC) and calcium hydroxide [Ca(OH)₂] intracanal medications (ICMs) in primary endodontic infection with apical periodontitis (PEIAP).

MATERIALS AND METHODS

Thirty-six teeth with PEIAP were randomly divided into groups according to the ICM: NAC, Ca(OH)₂ + saline solution (SSL), and Ca(OH)₂ + 2% chlorhexidine-gel (2% CHX-gel) (all, n = 12). Root canal samples (RCSs) were collected before (s1) and after instrumentation (s2) and after 14 days of ICM (s3). Chemomechanical preparation (CMP) was performed with a Reciproc file and 2.5% NaOCl. Checkerboard DNA-DNA hybridization was used to assess 40 target bacteria species.

RESULTS

At s1, bacterial DNA was detected in 100% of RCSs (36/36). All 40 bacterial species were found in PEIAP. The mean number of species per RCS was 17.92 ± 13.18. The most frequent bacteria were S. mitis (65%), E. nodatum (63%), E. faecalis (63%), F. nucl sp vicentii (58%), T. forsythia (58%), and F. periodonticum (56%). CMP reduced the mean number of species per RCS to 6.8 ± 2.36 (p < 0.05). At s3, the intragroup analysis revealed a broader antimicrobial activity for Ca (OH)₂ + 2% CHX-gel and NAC than Ca(OH)₂ + SSL (p < 0.05). NAC eliminated 8/12 bacteria species resistant to both Ca (OH)₂ ICMs, including P. micra, P. nigrescens, T. denticola, A. israelii, P. endodontalis, P. acnes, C. ochracea, and E. corrodens.

CONCLUSIONS

Ca (OH)2 + 2% chlorhexidine gel (2% CHX gel) showed a greater bacterial elimination over the number of bacterial species; however, NAC eliminated 8/12 bacteria species resistant to both Ca (OH)2 ICMs (RBR-3xbnnn).

CLINICAL RELEVANCE

The use of intracanal medication with a broad antimicrobial activity can optimize root canal disinfection. Ca(OH)₂ + 2% CHX gel and NAC showed a broader antimicrobial activity than Ca(OH)₂ + SSL against endodontic pathogens in primary root canal infection.

TRIAL REGISTRATION

Brazilian Registry of Clinical Trials (REBEC), No. RBR-3xbnnn.

An overview of systematic reviews on endotoxins in endodontic infections and the effectiveness of root canal therapy in its removal

Background The objective of this overview was to synthesise the current evidence on the role of endotoxins in endodontics infections and to evaluate the effectiveness of endodontic procedures in its removal using information from published systematic reviews.Methods Electronic databases Medline, Scopus, Embase, Cochrane Library and Google Scholar were searched for reviews published up to July 2021. Systematic reviews on endotoxins based on clinical and/or observational studies were included. The quality of systematic reviews was assessed with the AMSTAR2 tool.Results A total of five systematic reviews were selected, of which two reviews were of high quality. A significantly higher level of endotoxins were found in teeth with exudation, teeth with a previous episode of pain and pain on percussion. Chemomechanical preparation of root canals significantly reduce endotoxin levels. Calcium hydroxide intracanal medication in symptomatic teeth was significantly effective in endotoxin reduction (standardised mean difference -1.051 [95% confidence interval -2.039 to -0.063]; p <0.05; I2 = 83.3%; certainty of evidence = very low). Multiple session root canal treatment in teeth with symptomatic apical periodontitis was significantly more effective in endotoxins/lipopolysaccharides removal than single-session treatment.Conclusion Limited quality of evidence showed a significant association of endotoxins in infected teeth with clinical symptoms. Conventional chemomechanical preparation of root canals and intracanal medication were unable to eliminate endotoxins from the root canal system. Future evolution of effective disinfection therapies is warranted.

Comparison of GentleWave system and passive ultrasonic irrigation with minimally invasive and conventional instrumentation against LPS in infected root canals

This study compared the effectiveness of GentleWave system (GWS) and passive ultrasonic irrigation (PUI) in removing lipopolysaccharides (LPS) from infected root canals after minimally invasive (MIT) and conventional instrumentation (CIT) techniques. Sixty first premolars with two roots were inoculated with fluorescent LPS conjugate (Alexa Fluor 594). Of those, twelve were dentin pretreated, inoculated with fluorescent LPS conjugate, and submitted to confocal laser scanning microscopy (CLSM) to validate the LPS-infection model. Forty-eight teeth were randomly divided into treatment groups: GWS + MIT, GWS + CIT, PUI + MIT, and PUI + CIT (all, n = 12). Teeth were instrumented with Vortex Blue rotary file size 15/0.04 for MIT and 35/0.04 for CIT. Samples were collected before (s1) and after a root canal procedure (s2) and after cryogenically ground the teeth (s3) for intraradicular LPS analysis. LPS were quantified with LAL assay (KQCL test). GWS + MIT and GWS + CIT were the most effective protocols against LPS, with no difference between them (p > 0.05). PUI + CIT was more effective than PUI + MIT (p < 0.05) but less effective than GWS + MIT and GWS + CIT. GWS was the most effective protocol against LPS in infected root canals using MIT and CIT techniques.

Positively Charged Polyvinylidene Fluoride Membrane: A Potential Alternative for Absorbent Paper Points in Endodontics

INTRODUCTION

This study compared the absorbency capacity of paper points (PPs) with positively charged and noncharged polyvinylidene fluoride membranes (PVDFMs) and investigated the ability of PPs and PVDFMs to bind and remove endotoxin.

METHODS

Three commercially available PPs were compared with PVDFM (Millipore Sigma, Burlington, MA) prototype points. We recorded the initial dry weight for each PP and PVDFM using a digital balance to ±0.0001 precision for absorbency. PPs and PVDFMs were then immersed in deionized water and weighed to obtain the wet weight. The absorbency was calculated with the following formula: percent increase = ([wet weight - dry weight]/dry weight) × 100. For endotoxin removal, we first quantified endotoxin remaining in wells after immersing PPs and PVDFMs in a 24-well plate containing 10 endotoxin units/mL Escherichia coli O55:B5 (Lonza, Walkersville, MD). We then extracted and quantified endotoxin from PPs and PVDFMs. Endotoxin was quantified using the Kinetic-QCL test (Lonza).

RESULTS

The absorbencies for the positively charged and noncharged PVDFMs were higher than the PPs (P < .05), with no difference between them (P > .05). The positively charged PVDFMs removed more endotoxin than the noncharged PVDFMs and the PPs (P < .05). Moreover, the noncharged PVDFMs bound and removed more endotoxin than any PPs (P < .05).

CONCLUSIONS

PVDFM prototype points are more absorbent than PPs. Moreover, the positively charged PVDFM points are more effective in binding and removing endotoxin than noncharged PVDFMs and PPs. This study suggests that positively charged PVDFMs with a 0.22-μm pore size could potentially replace PPs used in endodontics.

CALCIUM HYDROXIDE (CA[OH]2) AS AN INTRACANAL MEDICATION MAY SIGNIFICANTLY REDUCE ENDOTOXINS LEVEL FROM INFECTED TEETH

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

Bedran NR, Nadelman P, Magno MB, de Almeida Neves A, Ferreira DM, Braga Pintor AV, Maia LC, Primo LG. Does Calcium Hydroxide Reduce Endotoxins in Infected Root Canals? Systematic Review and Meta-analysis. J Endod. 2020 Aug 11:S0099-2399(20)30582-3. doi:10.1016/j.joen.2020.08.002. Epub ahead of print. PMID: 32795549.

SOURCE OF FUNDING

This systematic review was supported in part by the Coordenaçao de Aperfeiçoamento de Pessoal de Nível Superior (finance code 001, 88882.424816/2019-01) and Fundaçao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro (grant nos. E-26/202.334/2019, E-26/202.399/ 2017, and E-26/210.352/2019).

TYPE OF STUDY/DESIGN

Systematic review with meta-analysis.