The effects of radicular dentine treated with double antibiotic paste and ethylenediaminetetraacetic acid on the attachment and proliferation of dental pulp stem cells.

AIM: This study explored the effects of dentine treated with two concentrations of double antibiotic paste (DAP) and ethylenediaminetetraacetic acid (EDTA) on the attachment and proliferation of dental pulp stem cells (DPSCs). MATERIALS AND METHODS: Radicular dentine samples were prepared with identical dimensions and randomized into six groups (n = 4). Four groups were treated with double antibiotic paste (DAP) at concentrations of 500 mg ml(-1) or 1 mg ml(-1) with or without EDTA. The other two groups were treated with EDTA only or received no treatment. DPSCs were seeded on each dentine sample (10 000 cells per sample). Lactate dehydrogenase activity assays were used to calculate the attached DPSCs after 1 day of incubation. Water soluble tetrazolium assays were performed to investigate DPSCs proliferation on the treated dentine samples after three additional days of incubation. Two-way anova followed by Tukey-Kramer tests was used for statistical analyses (α = 0.05). RESULTS: Dentine treated with 1 or 500 mg ml(-1) of DAP followed by EDTA caused significant increases in DPSCs attachment compared to the dentine treated with the DAP alone. The 500 mg ml(-1) of DAP with or without EDTA caused significant reductions in DPSCs proliferation. However, the treatment of dentine with 1 mg ml(-1) of DAP did not have significant negative effects on DPSCs proliferation regardless of the use of EDTA. CONCLUSION: The use of 1 mg ml(-1) of DAP followed by 10 min of irrigation with EDTA in endodontic regeneration procedure may have no negative effects on the attachment and proliferation of DPSCs.

Scanning Electron Microscopy Analysis of the Intratubular Radicular Dentin Penetration of Calcium Hydroxide, Triple Antibiotic Paste, and Nitrofurantoin.

The aim of this study is to assess and analyze the intratubular penetration of the intracanal medications nitrofurantoin (Nit), triple antibiotic paste (TAP), and calcium hydroxide (CH). Sixty freshly extracted single-rooted teeth were acquired and decoronated to a standard length of 15 mm. To prepare specimens up to size F3, rotary ProTaper instrumentation was employed. The prepared teeth were divided into three groups, each of which received one of the tested intracanal medicaments: Group I (calcium hydroxide), Group II (triple antibiotic paste), and Group III (nitrofurantoin). Using a size #30 Lentulo spiral, a freshly prepared therapeutic paste was placed into the canals, and the intracanal medicaments were allowed to set in the incubator at 100% humidity. The samples were subsequently sliced perpendicularly to their long axis using a precision saw and assessed under a scanning electron microscope to assess the depth of penetration of intracanal medicaments at the coronal, middle, and apical portions of the root canal dentin. The data were analyzed using one-way ANOVA and Tukey's post hoc test. The statistical analysis revealed a significant difference between the experimental groups in the quantity and depth of sealer penetration (p < 0.05). In particular, as compared to the Nit group, both the CH and TAP groups had significantly smaller penetration areas (p < 0.05). In conclusion, this ongoing investigation indicates that nitrofurantoin penetrated dentinal tubules better than calcium hydroxide or triple antibiotic paste.

Effect of Endodontic Irrigating Solutions on Radicular Dentine Structure and Matrix Metalloproteinases-A Comprehensive Review.

Irrigating solutions play an important role in the eradication of intracanal microbes and debris dissolution during endodontic treatment. Different combinations of solutions and protocols have been advocated, with sodium hypochlorite (NaOCl), ethylenediamine tetra acetic acid (EDTA), and chlorhexidine (CHX) remaining the most widely used ones by many clinicians. Although these solutions provide efficient inorganic dissolution and antimicrobial capacity, their use has also been reported to cause undesired effects on root dentin composition and mechanical and biomechanical properties, such as microhardness, surface roughness, bond strength, and matrix metalloproteinase (MMP) activity. Several corroborating studies attribute these changes in mechanical properties of dentine to the use of irrigating solutions, and there are limited reports on how the solutions affect the expression of MMPs, which may be a correlating link to understanding the role of these enzymes in dentin collagen and changes in the mechanical properties of dentin. Hence, using the basis of several studies from the literature, the objective is to comprehensively review the influence of individual and combined irrigating solutions on root dentine structure and the activity of the MMPs.

Long-term treatment of dentine with triple antibiotic paste promotes stem cell viability and attachment.

Objective: Successful regenerative endodontic procedures in dental treatment are critically associated with complete disinfection of the root canal and require irrigants and medicaments. One factor for consideration is the biocompatibility of the medicament as this can affect the intracanal dentine and subsequently the dental stem cell viability required for the repair of the dentine-pulp complex. This in vitro study investigated the effect of a 4-week treatment of calcium hydroxide [Ca(OH)2] and triple antibiotic paste (TAP) on the irrigated radicular dentine by analysing dentine interaction with dental stem cells. Methods: TAP consists of metronidazole, ciprofloxacin and minocycline. Dentine chips were prepared and treated with either Ca(OH)2 or TAP for 4-weeks, irrigated by 1.5% sodium hypochlorite (NaOCl), rinsed with saline, followed by 17% ethylenediaminetetraacetic acid (EDTA). Dental pulp stem cells (DPSCs) cultured on the surface of the dentine chips were analysed on days 1, 3 and 7 of cell seeding for PrestoBlue viability assays, 6-diamidino-2 phenylindole (DAPI) staining and scanning electron microscopy (SEM). An independent t-test (SPSS software version 24.0) was used to statistically analyse the PrestoBlue assay data. Results: DPSCs grown from dentine treated with TAP showed significantly higher cell viability than the Ca(OH)2 and control groups (p < 0.05). DAPI staining of the seeded DPSCs on the treated dental chips complemented the findings of the viability assay. SEM studies also revealed improvements in the cell spreading and attachment of DPSCs grown on TAP-treated dentine compared with Ca(OH)2. Conclusion: The treatment of dentine with TAP for 4 weeks provided a better microenvironment for the viability and attachment of DPSCs when compared to Ca(OH)2.

Erosive Potential of 1% Phytic Acid on Radicular Dentine at Different Time Intervals.

Objective: The objective of this in-vitro study was to compare the erosive potential and smear layer removal ability of 1% Phytic acid (IP6) and 17% Ethylenediaminetetaacetic acid (EDTA). Methods: Canal preparation of 225 single rooted extracted human teeth was performed with Protaper NiTi rotary instruments. Teeth were divided into three groups according to the final irrigation protocol. Group 1: Saline irrigation (n=75), Group 2: 17% EDTA (n=75), Group 3: 1% Phytic Acid (n=75). Roots were splitted and observed under Scanning Electron Microscope (SEM) for erosion and smear layer removal. Mean differences between the groups for smear layer removal and erosion were assessed using the Kruskal Wallis and Mann Whitney U test. (P≤0.05) Friedman and Willcoxon Signed Rank tests were used to make comparisons within the groups. Results: Group 3 was significantly less erosive than Group 2 at all root portions (P<0.001). With regards to smear layer removal, group 2 (EDTA) removed more smear layer compared to group 3 (Phytic acid) at all root portions (P<0.001). Both 17% EDTA and 1% IP6 removed significantly less smear layer in the apical root portion. Intra group comparisons revealed no significant differences at any root level. There was a time dependent increase in erosion and smear layer removal in Group 2, with severe erosion at 5 minutes time interval. In Group 3, however, there was moderate erosion and smear removal at 3 and 5 minutes interval. Conclusion: IP6 at the concentration of 1% and pH 3 was less erosive than 17% EDTA. It exhibited moderate smear layer removal ability.

Incorporating N-acetylcysteine and tricalcium phosphate into epoxy resin-based sealer improved its biocompatibility and adhesiveness to radicular dentine.

OBJECTIVE: This in vitro study was designed to evaluate the biocompatibility, adhesiveness, and antimicrobial activity of epoxy resin-based sealer associated with N-Acetylcysteine (NAC) or beta-tricalcium phosphate nanoparticles (ß-TCP) as an experimental retro-filling material. METHODS: Cytotoxicity was assessed using 2,3-Bis-(Methoxy-4-Nitro-5-Sulphophenyl)-2H-Tetrazolium-5-Carboxanilide (XTT) and Sulforhodamine B (SRB) assays after exposing human periodontal ligament fibroblasts to extracts of the materials for 1, 3, or 7 days. For the adhesive resistance test, root canals (48 single-root teeth) were instrumented with Reciproc #40 files (VDW GmbH, Germany) and obturated. After 7 days, the apices were sectioned and a retrograde cavity prepared and filled with the experimental materials (Mineral trioxide aggregate, Epoxy sealer, Epoxy sealer+NAC, and Epoxy sealer+ß-TCP). For the push-out test, one 2-mm thick slice was obtained from the apical third of each specimen. Antimicrobial activity was performed using agar diffusion method. Biofilms were grown in microplates and exposed to the extracts of retro-filled materials, followed by analysis of growth inhibition on agar plates. RESULTS: Epoxy sealer in association with ß-TCP or NAC showed better bond strength while Mineral trioxide aggregate allowed for the lowest adhesion. Mineral trioxide aggregate, Epoxy sealer+ß-TCP, and Epoxy sealer+NAC showed low cytotoxicity. Epoxy sealer was the most cytotoxic. In antimicrobial activity assays, all materials had no effect on Candida albicans. Addition of NAC improved the antimicrobial property of Epoxy sealer against Enterococcus faecalis compared to unmodified Epoxy sealer (P<0.05). SIGNIFICANCE: Incorporating ß-TCP or NAC with Epoxy sealer could improve the adhesiveness and biocompatibility for better use in endodontic therapy.

Changes in the radicular pulp-dentine complex in healthy intact teeth and in response to deep caries or restorations: A histological and histobacteriological study.

INTRODUCTION: The present study reported the histological events that occurred in the radicular pulp of human mature teeth in the presence of medium/deep untreated caries lesions, and those teeth with restorations or direct pulp capping, with particular emphasis on the morphology of the canal wall dentine and the odontoblast layer. METHODS: Sixty-two teeth with medium/deep caries lesions, extensive restorations or after application of a direct pulp capping procedure were obtained from 57 subjects. Fourteen intact mature teeth served as controls. Stained serial sections were examined for the pulp conditions of the coronal pulp. The teeth were classified as those with pulpal inflammation, or those with healed pulps. Histological changes that occurred in the roots at the pulp-dentine junction were investigated in detail. RESULTS: All teeth (100%) in the experimental group showed pathologic changes in the radicular pulp, with varying amounts of tertiary dentine on the canal walls and absence of odontoblasts. These changes were identified from different portions of the canal wall surface. Non-adherent calcifications in the pulp tissue were observed in more than half of the specimens. Changes that deviate from classically-perceived histological relationships of the pulp-dentine complex were also observed in the radicular pulps of 33.7% of the control teeth. CONCLUSION: When challenged by bacteria and bacterial by-products invading dentinal tubules, odontoblasts in the radicular pulp may undergo cell death, possibly by apoptosis. This phenomenon may be caused by progressive root-ward diffusion of bacterial by-products, cytokines or reactive oxygen species through the pulp connective tissue. CLINICAL SIGNIFICANCE: Although the vitality of the dental pulp in teeth with deep dentinal caries may be maintained with direct pulp capping or pulpotomy, the repair tissue that is formed resembles mineralised fibrous connective tissues more than true tubular dentine.