On the biocompatibility of endodontic sealers

Periapical tissue may be exposed to root canal filling materials in consequence of root canal therapy. There is scant scientific data about the biocompatibility of root canal filling materials of various chemistry on the periapical area. This study aimed to investigate the effects of different root canal sealers and their eluates on human alveolar osteoblasts in terms of cell proliferation, adhesion, morphology and gene expression in vitro. Five endodontic sealers (AH Plus®, Apexit®, Tubli-Seal®, Real Seal SE®, EndoRez®) and one gutta-percha obturation material (BeeFill®) were tested. Human alveolar osteoblasts derived from 3 different donors following incubation with sealer eluates after 24 h and 72 h were investigated by means of qPCR (gene expression). Morphological reactions of the alveolar osteoblasts were measured by culturing the cells for 3 d, and 7 d and 14 d, respectively, followed by scanning electron microscopy (morphology, adhesion) and fluorescence imaging of the actin cytoskeleton (morphology, proliferation). A repeated measures analysis was performed and p-values were adjusted by Tukey. While all sealers influenced the cell morphology and the expression of genes associated with apoptosis (Casp3), proliferation (histone H3), and inflammation (interleukin-6 and matrix metalloproteinases 1 and 3), mainly AH Plus® and Apexit® yielded a regular actin cytoskeleton and beneficial gene expression patterns. Regarding cell adhesion, only AH Plus® supported proper anchorage for alveolar osteoblasts. Our results provide evidence for the biocompatibility of epoxy resin-based endodontic sealers, i.e. AH Plus®, while other sealers proved cytotoxic for alveolar osteoblasts. Further studies are needed for understanding the bone cell reactions after endodontic treatment and the clinical decision-making regarding the sealer of choice for root canal fillings

Endodontic sealers after exposure to chlorhexidine digluconate:An assessment of physicochemical properties

Objectives Final root canal irrigation should ideally maintain the physicochemical stability of root canal sealers. We seek to assess the effect of contact with 2% chlorhexidine digluconate (CHX) on the physicochemical properties of AH Plus, BioRoot™ RCS, and Pulp Canal Sealer (PCS). Methods Mixed sealers were placed in cylindrical teflon molds and allowed to set for 1.5x the manufacturers’ setting time. Half of the specimens had their free surface in contact with CHX for the first minute of their setting period. Solubility, radiopacity, surface roughness, microhardness and wettability of the sealers were assessed up to 28 days after setting. Elemental analysis of sealer surfaces and their leachates together with pH measurements were also performed. Appropriate parametric and non-parametric analysis with post hoc tests were performed (p < 0.05). Results Exposure to CHX had no effect on solubility and radiopacity of all sealers. CHX altered the surface roughness of PCS and BioRoot RCS (p < 0.05). Contact with CHX reduced the microhardness of AH Plus and PCS (p < 0.05). AH Plus was more hydrophilic after CHX contact, whereas PCS became more hydrophobic (p < 0.05). AH Plus and PCS surfaces appeared to adsorb CHX as exhibited by chlorine peaks after contact with CHX. Sealer leachates’ alkalinity was not affected. CHX increased elution of silicon and zirconium for BioRoot and zinc for PCS leachates. Significance In our study, CHX affected sealers’ physicochemical properties to various extents. Further studies are needed to confirm the obtained results by investigating various final irrigation strategies and correlating to biological properties

Effect of chlorhexidine digluconate on antimicrobial activity, cell viability and physicochemical properties of three endodontic sealers

ObjectiveAssess the biological and physicochemical properties of AH Plus, BioRoot RCS and Pulp Canal Sealer (PCS) leachates with and without chlorhexidine (CHX).MethodsThe sealers were studied in no contact and 1-minute contact with CHX. For biological properties (antibacterial activity and cytotoxicity), leachates were formed in saline of freshly mixed, 1-, 7- and 28 days set sealers. The antibacterial properties of sealer leachates were investigated for planktonic and biofilm growth of E. faecalis, S. mutans, S.epidermidis and S.aureus. The 3-(4,5 dimethylthiazolyl-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to evaluate murine fibroblast cell viability after exposure to the leachates. The physical properties (water uptake, sorption, solubility, porosity, surface characteristics) of sealers and the pH of the immersion liquid (saline or distilled water) were also assessed over a 28-days period.ResultsCHX improved the antibacterial properties of the sealer leachates and reduced cell viability for all sealer leachates, except for freshly mixed PCS. BioRoot RCS leachates presented the highest antibacterial properties and cell viability with and without CHX contact. PCS was the material most affected by CHX in terms of physical properties, whereas for AH Plus, solubility was increased. CHX did not affect the physical properties of BioRoot RCS, except for solubility that was decreased. CHX contact did not change sealers’ alkalinity in distilled water whereas it increased it for AH Plus and BioRoot RCS in saline.SignificanceCHX improved the antibacterial efficacy of sealer leachates and either compromised or did not affect cell viability. CHX affected to various extent sealers’ physicochemical properties

Technical Quality and Associated Iatrogenic Errors of Endodontic Treatments Performed in Extracted Anterior Single-Rooted Teeth by Preclinical Undergraduate Students

Aim: To evaluate technical quality of root canal treatments performed in extracted anterior single-rooted teeth in an undergraduate dental clinic, and to record the associated iatrogenic errors

Surface characteristics and bacterial adhesion of endodontic cements

OBJECTIVES: To investigate the effect of inclusion of silver nano-particles (SNP) or bioactive glass (BG) on the surface characteristics and bacterial adhesion of prototype tricalcium silicate (TCS)–based cements alongside two commercial cements, under different aging periods and exposure conditions. MATERIALS AND METHODS: A basic formulation of radio-opacified TCS without (TZ-base) and with additions of SNP (0.5, 1, or 2 mg/ml) or BG (10 or 20%) was used. Biodentine and intermediate restorative material (IRM) served as reference materials. Material disks were immersed in ultrapure water or fetal bovine serum (FBS) for 1, 7, or 28 days. Surface roughness (n = 3), microhardness (n = 9), and wettability (n = 6) were analyzed by standard procedures. Adhesion of Enterococcus faecalis was assessed by fluorescence microscopy (n = 5). Data from these assays were evaluated for normality and comparisons among groups were conducted with statistical procedures (p  0.05). Biodentine presented smooth surface characteristics and the highest hardness values (p < 0.05). The FBS-immersion resulted in surface reactions in prototype materials and Biodentine, depicted with scanning electron microscopy. All 1- and 7-day prototype cements showed negligible bacterial adhesion, while in Biodentine and IRM, noticeable E. faecalis adherence was observed from day 1 (p < 0.05). CONCLUSIONS: Incorporation of SNP or BG did not improve the antibacterial effect of the experimental cement; all 28-day aged materials failed to inhibit bacterial adherence. The measured physical parameters did not appear to be related to the degree of bacterial adhesion. Exposure of TCS-based cements in FBS resulted in surface reactions, which did not affect bacterial adhesion. CLINICAL RELEVANCE: Changes in the surface characteristics of prototype TCS-based cements by inclusion of SNP and BG or exposure to different environments did not affect bacterial adhesion. All experimental materials showed inferior physical properties and higher antibacterial effect than Biodentine. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00784-022-04655-y