Comparison of physico-chemical properties of zinc oxide eugenol cement and a bioceramic sealer.

The aim of the present study was to compare the physico-chemical properties of EssenSeal with AH PLUS bioceramic and Pulp Canal Sealer EWT. Flow, solubility, film thickness, radiopacity and setting time were evaluated according to ISO 6876 (2012) specifications. External and cross-section surface characteristics were analysed under a scanning electron microscope. Statistical analysis was performed using Shapiro-Wilk's test, one-way ANOVA and the Tukey HSD test. All the sealers conformed to the ISO 6876 (2012) standards, except for the setting time for AH plus bioceramic, which exceeded more than 10% of the time indicated by the manufacturer. Statistically significant differences were found between the three study sealers regarding the physico-chemical properties tested (p < 0.05). EssenSeal demonstrated characteristics respecting the ISO 6876 (2012) standards and can be considered a predictable alternative in root canal sealing.

The Pushout Bond Strength of Three Calcium Silicate-based Materials in Furcal Perforation Repair and the Effect of a Novel Irrigation Solution: A Comparative In Vitro Study.

AIM: To evaluate the pushout bond strength of three calcium silicate-based materials used as furcal perforation repair materials and the effect of root canal irrigants on the pushout strength of the tested repair materials. MATERIALS AND METHODS: Furcal perforations measuring 1.3 mm in diameter were made in the center of the furcation area of 90 extracted human mandibular molars. The teeth were then randomly divided into three groups (n = 30) according to the repair material: Biodentine (Septodont, St-Maur-des-Fossés, France), PD-MTA White (Produits Dentaires, Vevey, Switzerland), and K-Biocer (REKITA, Lebanon). The specimens were stored at 100% humidity at 37°C for 72 hours. They were later divided into three subgroups (n = 10) based on the irrigation protocol: 2.5% sodium hypochlorite, BioAKT (Metabolic substrate, New Tech Solutions s.r.l., Brescia, Italy), and a control group. After incubation for 48 hours, the dislodgement resistance of the samples was measured using a universal testing machine. RESULTS: The mean bond strength was significantly different between repair materials in the irrigation control group (p-value <0.001). With PD-MTA White and K-Biocer, the mean bond strength was not significantly different between irrigation groups (p-value = 0.681). The mean bond strength of Biodentine was significantly different between irrigation groups (p-value = 0.002); it was the highest with BioAKT. CONCLUSION: Biodentine showed a high performance as a perforation repair material and its resistance to dislocation increased after being exposed to BioAKT. K-Biocer had the lowest pushout bond strength. PD-MTA White showed intermediate bond strength and was not affected by the tested irrigants. CLINICAL SIGNIFICANCE: The bond strength of endodontic materials to root dentin is an important factor to consider for long-term clinical success since the teeth are constantly subjected to masticatory forces.

Corrigendum: Irrigating Solutions and Activation Methods Used in Clinical Endodontics: A Systematic Review.

[This corrects the article DOI: 10.3389/froh.2022.838043.].

Irrigating Solutions and Activation Methods Used in Clinical Endodontics: A Systematic Review.

BACKGROUND: Ex vivo and in vitro studies have demonstrated the effectiveness of some irrigation protocols in reducing the bacterial load in the root canal system. However, standardized protocols have not yet been defined for the real clinical context due to many irrigation procedures available. OBJECTIVE: To evaluate the clinical endodontic protocols and limitations of irrigating solutions in the disinfection of the root canal system in patients with apical periodontitis. METHODS: PubMed, Scopus, Embase, Web of Science, and Cochrane databases were searched for randomized controlled trials (RCT) published until January 2021. Hand searching was also performed. Studies focused on evaluating the effectiveness of irrigating solutions and/or irrigation activation methods in reducing the bacterial load in the root canal system were considered. The Cochrane risk-of-bias tool for randomized trials (RoB2) was used to assess the quality of the studies. RESULTS: Four hundred and twenty eight published articles were identified. After removing the duplicate studies and analyzing full texts, seven RCTs were selected. Two studies compared pure NaOCl with some combination of NaOCl with HEDP and MTAD. Two studies analyzed the antibacterial efficacy of NaOCl and chlorhexidine (CHX). Three studies compared conventional needle irrigation with different irrigation activation methods (PUI, XP-endo finisher, F-file activator, EndoVac activator). The review attained a satisfactory methodology. The main results of each included study were described. DISCUSSION: Activation methods provide significantly higher biofilm reduction than conventional needle irrigation methods. Combinations of NaOCl with different chelating agents were ineffective in terms of antimicrobial, but it could potentially increase the risk of irrigant extrusion. However, the irrigating protocols were not carefully detailed, especially those regarding the irrigants application time or total volume. The existing literature lacks high-quality studies. The level of evidence is moderate. CONCLUSIONS: The available data is too heterogeneous to compare and identify the superiority of specific valuable irrigation protocols in each clinical context. Application time, volume, and activation methods should be standardized to determine the optimal irrigating procedures to reduce the bacterial load and ensure higher predictability of the endodontic treatment. SYSTEMATIC REVIEW REGISTRATION: (https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=218555), PROSPERO registration: CRD42020218555.

In Vitro Evaluation of Antibacterial Properties and Smear Layer Removal/Sealer Penetration of a Novel Silver-Citrate Root Canal Irrigant.

This study aimed at evaluating the efficacy of a novel silver-citrate root canal irrigation solution (BioAKT) on smear layer removal, sealer penetration after root canal instrumentation and antibacterial activity. Single-root teeth were endodontically treated, sealed with an epoxi-amine resin sealer and irrigated using: Group I: 5.25% sodium hypochlorite (NaOCl); Group II: silver-citrate solution (BioAKT); Group III: phosphate buffer solution (PBS); Group IV: 17% ethylenediaminetetraacetic acid (EDTA). Smear layer removal and silver deposition at the coronal, middle and apical portion of each canal were analyzed using scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS). Sealer penetration into dentinal tubules at coronal, middle and apical portion was assessed through dye-assisted confocal microscopy (CSM). Both SEM and CSM micrographs were evaluated by two examiners (κ = 0.86), who were blind to the irrigation regimens; scores were given according to the degree of penetration of the sealer. Data analysis included Pearson's x2 and Sidak's multiple comparisons. Dentin discs were polished and sterilized. Enterococcus faecalis biofilms were grown using a continuous-flow bioreactor under anaerobic conditions for 72 h. Specimens were irrigated with the tested solutions, and bacterial viability was assessed using a tetrazolium salt assay (MTT). Statistical analysis included one-way ANOVA and Student's post-hoc t-test (p < 0.05). BioAKT and EDTA were the most efficient solutions both in removing the smear layer and allowing sealer penetration. However, at the apical portion BioAKT performed significantly better compared to EDTA both in smear layer removal and sealer penetration (p < 0.05). BioAKT and NaOCl showed comparable antibacterial effect (p = 0.53). In conclusion, BioAKT represents a suitable smear layer removal agent, which allows for reliable sealer penetration at the apical portion of the root canal system and offers significant antibacterial properties.

Novel hollow fiber sandwich composite post system: mechanical characteristics.

BACKGROUND: There is currently no consensus on the optimal post system to provide effective long-term results. We used an engineering approach to investigate the mechanical properties of a sandwich hollow carbon fiber post in synergy with a new bonding technique. METHODS: We studied two systems - a sandwich fiber hollow post (Techole®, Isasan, Como, Italy) composed of carbon fiber incorporated in a Dpp-MOR resin mix and a traditional non-hollow post (Tech 2000®, Isasan, Como, Italy). A bi-component composite (Clearfil Core®, Kuraray, New York, NY, USA) (2.2 gcm3, 12.3 GPa) and a dual cure composite with lower density and modulus of elasticity (Clearfil DC Core®, Kuraray, New York, NY, USA) (2.0 gcm3, 10.0 GPa) were also used into hollow posts. Results from three-point bending test (N.=81), compression test (N.=78) and cut test (N.=81) were achieved. RESULTS: In the three-point bending test there were significant differences in flexibility/bending when sandwich fiber hollow posts were filled with composite of different modulus of elasticity. Hollow sandwich posts showed also significant (P=0.000) better resistance to compression and cutting than solid posts, independently of the type of composite. Moreover, hollow posts filled plus composite with a modulus of elasticity of 12.3 GPa showed significant (P=0.000) improved resistance parameters rather than hollow posts filled with a composite of 10.0 GPa. CONCLUSIONS: The study confirms the favorable mechanical properties of the hollow sandwich fiber post system (Techole®) and the synergistic efficacy when used in combination with the composite Clearfil DC Core® (10.0 GPa) and, especially, Clearfil Core® (12.3 GPa).

The Effect of Cold Atmospheric Plasma (CAP) Treatment at the Adhesive-Root Dentin Interface.

PURPOSE: To investigate the use of a cold atmospheric plasma (CAP) source in a clinically realistic endodontic procedure to enhance the bond strength of a dental adhesive in root canal restoration. MATERIALS AND METHODS: CAP was generated by a handheld DBD-jet prototype specifically designed for biomedical applications. Extracted monoradicular teeth were standardized through crown sectioning and root canal shaping before being embedded in epoxy resin cylinders using a custom molding procedure designed to ensure the accurate alignment of the specimens. Afterwards, the dentin surface was conditioned according to different protocols including (or not, in controls) chelating agents (EDTA or IP6) and CAP treatment (180 s). Then a self-etch adhesive was applied, followed by a luting material to seal the root canal. Both materials were light cured. Tooth sections were obtained from coronal and middle portions of the root canal, and the push-out test was used to evaluate the bond strength between the adhesive and dentin. RESULTS: Push-out results demonstrated that plasma treatment greatly improved (> twofold) the mechanical properties of the adhesive-dentin interface along the whole length of the root canal. Contact angle measurements and SEM analyses showed that plasma treatment facilitated adhesive permeation into dentinal tubules, hence enhancing the effects of the bonding procedure. CONCLUSIONS: Although investigations on long-term bond stability after CAP treatment and clinical studies are required, the present study indicates that CAP devices may be useful in clinical endodontic treatment.

Plasma in Dentistry: Brief History and Current Status.

We briefly discuss the history of cold atmospheric plasma (CAP) applications in dentistry. The reasons for seeking innovative solutions in dentistry are reported, highlighting results showing the potential of plasma along with some still-open questions. Finally, we suggest the next steps on the road from the laboratory to the dental chair.

An Innovative Method for Fragment Reattachment after Complicated Crown Fracture.

The case of a nineteen-year-old female with atypical fractures to three maxillary incisors (#11 FDI, #8 universal; #21 FDI, #9 universal and #22 FDI, #10 universal) with one showing a complicated crown fracture and pulp exposure is reported. A partial pulpotomy had been carried out immediately after trauma and the patient complained of acute pain on percussion of the left central incisor. Direct restoration with resin-based composite was carried out on the two teeth where fragments were not available (tooth #8 and #10) and root canal treatment with reattachment of fragments and fiber post was carried out on the third (tooth #9). An innovative method was used to reattach the tooth fragments whereby the fiber post was inserted without drilling a hole in the crown thus preserving the integrity of the crown. Follow-up visits confirmed the success of treatment based on clinical and radiographic evaluations. The patient was pain free with no tooth sensitivity and good function and esthetics after four years of follow-up. CLINICAL SIGNIFICANCE: Case report with a follow-up of 4 years, provides confirmatory evidence of the long-term efficacy of an innovative method to reattach tooth fragments whereby fiber post is inserted without drilling a hole in the crown thus preserving the integrity of the crown. (J Esthet Restor Dent 29:172-177, 2017).