Antimicrobial effect of Pentaclethra Macroloba plant extract against Enterococcus Faecalis.

This study evaluated the antimicrobial efficacy of a new intracanal drug based on Pentaclethra macroloba extract, a plant of Amazonian origin, against Enterococcus faecalis using macrodilution test and intratubular evaluation with Confocal Laser Scanning Microscopy (CLSM). The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of the pure extract of Pentaclethra macroloba andits association with calcium hydroxide and ultracall were determined. Then, thirty-three dentin cylinders were prepared and inoculated with E. faecalis, to evaluate the antimicrobial effect of the medications on the dentinal tubules with CLSM. The data was analyzed using the Kruskal-Wallis and Dunn tests. The extract in association with calcium hydroxide showed a lower CBM, and in the intratubular test all tested medications were effective against E. faecalis (P >0.05). The new intracanal drug based on P. macroloba extract has an antimicrobial effect against E. faecalis and further studies are needed for its clinical use.

Medium-term evaluation of the bond strength and dentin penetration of self-adhesive resin cements to root dentin.

BACKGROUND: Medium-term evaluate the bond strength and tag formation in root dentin using self-adhesive cements Maxcem Elite (MCE), Relyx U200 (RU2), SeT PP (SPP) and Megalink (MGL) compared to conventional cement Relyx ARC (ARC) for glass fibre post cementation. MATERIALS AND METHODS: One hundred bovine incisors roots were endodontically treated and divided into 5 groups (n = 20) according to the cementation system: MCE, RU2, SPP, MGL and ARC. All cementation systems were evaluated at 24 h (1) and 12 months (2) after post cementation. Specimens from the cervical, middle and apical thirds of the root were submitted to push-out bond strength test and confocal laser microscopy to verify the dentin penetration. The adhesive failure mode was classified as adhesive, cohesive and mixed. Data were analysed by one-way ANOVA and Tukey tests (α = 5%). RESULTS: ARC-1 and ARC-12 showed the highest bond strength (P < 0.05). ARC showed the greatest tag extension, regardless of the third (P < 0.05). The most frequent failure mode in the 24-h analysis was cohesive, regardless of the cement used. For the 12-month analysis, mixed failure was the most frequent. CONCLUSION: Conventional cement (ARC) showed the highest bond strength and tag extension, regardless of the evaluation period. In all cementation systems, the bond strength decreased after 12 months. © 2023 Australian Dental Association.

Effect of Different Irrigants on the Adhesive Interface and Influence on the Push Out Strength of Fiber Posts.

PURPOSE: The aim of this study was to evaluate the effects of a new irrigant solution on the post space cleaning and the adhesive resistance of fiber posts. METHODS AND MATERIALS: Eighty roots of bovine teeth were randomly allocated into eight groups (n=10 for each group). Evaluations were performed in two different time points for each irrigant. The irrigants included a control group with distilled water (DW), 2.5% NaOCl and 17% EDTA (SH), 1% peracetic acid (PA), and 5% boric acid and 1% citric acid (EX). The time points were 24 hours (I-immediate) and 6 months (D-delayed). The push-out test was performed using a universal testing machine with a 5 kN load cell operating at a crosshead speed of 0.5 mm/minute. The dentinal cementation system was analyzed using a laser confocal microscope (LSM5, Zeiss, Jena, Germany), and incidence of residue on radicular dentin was evaluated by scanning electron microscopy (SEM). The incidence of residue was evaluated by the Kruskal-Wallis test and push-out bond strength and dentin penetrability were evaluated via a one-way analysis of variance (ANOVA) and Tukey tests (α=0.05). RESULTS: The EX irrigation protocol demonstrated the lowest incidence of residue on the dentin surface (p<0.05), independently of the evaluated third. In the cervical and the middle post thirds, EXI, EXD, SHI, and SHD groups exhibited similar push-out bond strength values (p>0.05). EXI, EXD, PAI, and PAD exhibited the greatest dentinal penetrability of the cementation system in all the post thirds (p<0.05). CONCLUSIONS: A solution containing 5% boric acid and 1% citric acid can be a promising irrigant for radicular post space cleaning. It has adequate potential for cleaning the dentin surface without interfering with the adhesive interface between the dentin and the cementation system.

Customized Fiber Post Improves the Bond Strength and Dentinal Penetrability of Resin Cementation System to Root Dentin.

OBJECTIVE: This study aimed to evaluate the effect of fiber post customization on the bond strength (24 hours and 6 months), resin cement thickness, and dentinal penetrability of Adper Scotchbond Multi-Purpose - RelyX ARC (AS-RA), RelyX U200 (R2), and Scotchbond Universal - RelyX Ultimate (SU-RU) cementation systems to root dentin from the cervical-, middle-, and apical-thirds of the post space. METHODS: One hundred twenty bovine incisors were endodontically treated. After post space preparation, the roots were divided into six groups, according to the luting protocols (AS-RA, R2, SU-RU) and the type of fiber post [noncustomized post (NC) and customized post (C)]. Customization procedures were peformed using a resin composite (Z350 XT). 24 hours (n=60) or 6 months later (n=60), specimens from the cervical-, middle-, and apical-thirds of the post space were submitted to cementation system thickness measurement, bond strength evaluation, and dentinal penetrability analysis with Confocal Laser Scanning Microscopy (CLSM). Failure mode was classified as adhesive, cohesive, or mixed. Data were submitted to ANOVA and Tukey tests (α=0.05). RESULTS: Cementation protocols with customized fiber posts presented the lowest cementation system thickness, regardless of the cementation system or post space-third (p<0.05), and the highest bond strength values (p<0.05), regardless of the third space (p>0.05), for both periods (24 hours or 6 months). The comparison of push-out bond strength values between 24 hours and 6 months showed a reduction in all groups for the cervical-third (p<0.05). For the middle-third, only noncustomized groups showed reduction (p<0.05). For the apical-third, no reduction was observed (p>0.05). CONCLUSIONS: Anatomical customization favored both the bond strength of cements to dentin and the dentinal penetrability, but with lower cementation system thickness, regardless of cement composition and adhesive strategy.

Effects of Remineralizing Agents Based on Calcium Phosphate, Sodium Phosphate, or Sodium Fluoride on Eroded Cervical Dentin.

OBJECTIVES: To evaluate the effect of remineralizing agents on collagen matrix pattern, precipitate formation, and dentinal tubule obliteration in eroded cervical dentin. METHODS AND MATERIALS: One hundred bovine cervical dentin specimens were previously eroded (0.6% hydrochloric acid, pH 2.3, 5 minutes) and then randomized into five groups (n=20): G1, control (without treatment); G2, Desensibilize Nano P (FGM); G3, MI Paste Plus (Recaldent); G4, Regenerate (NR-5); and G5, Desensibilize KF 2% (FGM). These treatments were applied in four sessions with 7-day intervals. During this period, the samples were subjected to an erosive challenge with orange juice (pH 3.8, 5 minutes). The specimens were analyzed by polarized light microscopy with picrosirius red staining, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). RESULTS: The G3 showed a higher concentration of type I collagen than G2 and G5 (p<0.05). The G3 showed greater formation of surface precipitates than that of G1 and G5 (p<0.05). In addition, G4 and G5 showed a greater number of open dentinal tubules than that of G3 (p<0.05). CONCLUSIONS: Calcium phosphate-based remineralizing agents have shown to be a promising alternative treatment for preventing deleterious effects on the eroded dentin collagen matrix. In addition, they promoted precipitate formation and dentinal tubule obliteration on the eroded dentin.

Protocols for Mechanical Cleaning of the Post Space on the Bond Strength Between Root Dentin and Cementation System.

OBJECTIVE: To evaluate the effects of mechanical versus chemical cleaning protocols for cleaning the root dentin surface before cementation of fiberglass posts for their effect on the bond strength, failure mode, and dentinal penetration of the cementing agent using an etch-and-rinse adhesive system on dentin prepared to receive a fiberglass post. METHODS: Forty roots of bovine teeth were endodontically treated and prepared for fiber post cementation. The specimens were randomized into 4 groups of 10: Control group (CO) - irrigation with 2.5% NaOCl; DW group- irrigation with distilled water; RB group - rotating brush for cleaning root canals, and CUI group - continuous ultrasonic irrigation. The fiberglass posts were cemented, and the specimens were immersed in distilled water for 6 months. A push-out test was performed on the cervical, middle, and apical thirds of the samples. Dentinal penetration of the cementing agent and the fracture pattern were evaluated by laser confocal microscopy. Statistical analysis was performed using analysis of variance (ANOVA) and post hoc Tukey tests (α=0.05). Results: The RB and CUI groups showed significantly higher bond strength values when compared to the Control and DW groups (p<0.05). In addition, in the control and DW groups, the apical third presented lower bond strength values when compared to middle and cervical thirds. CONCLUSION: While DW showed the highest incidence of adhesive type failure, CUI resulted in the highest dentinal penetration of the cementing agent (p<0.05). RB and CUI resulted in the highest bond strength between cementation system and root dentin. In addition, CUI favored greater dentinal penetration of fiberglass post cementing agent.

Antibacterial properties of silver nanoparticles as a root canal irrigant against Enterococcus faecalis biofilm and infected dentinal tubules.

AIM: To evaluate the antimicrobial action of an irrigant containing silver nanoparticles in an aqueous vehicle (AgNp), sodium hypochlorite and chlorhexidine against Enterococcus faecalis biofilm and infected dentinal tubules. METHODOLOGY: Bovine dentine blocks were used for E. faecalis biofilm development for 21 days and irrigated with 94 ppm AgNp solution, 2.5% NaOCl and 2% chlorhexidine for 5, 15 and 30 min. For infection of dentinal tubules with E. faecalis, dentine specimens from bovine incisors were submitted to a contamination protocol over 5 days, with eight centrifugation cycles on every alternate day, and irrigated with the same solutions and time intervals used for the biofilm. The specimens were stained with the Live/Dead technique and evaluated using a confocal laser scanning microscope (CLSM). The bioImage_L software was used for measurement of the total biovolume of biofilm in µm3 and percentage of viable bacteria (green cells) in biofilm and in dentinal tubules found after the irrigation. Statistical analyses were performed using Kruskal-Wallis and Dunn's tests for quantification of viable cells in biofilm, the Friedman test for comparisons of viable bacteria in dentinal tubules in different areas of the root canal and the Mann-Whitney U-test to compare the action of the irrigants between the two methods (P < 0.05). RESULTS: The AgNp solution eliminated fewer bacteria, but was able to dissolve more biofilm compared with chlorhexidine (P < 0.05). NaOCl had the greatest antimicrobial activity and biofilm dissolution capacity. AgNp solution had less antimicrobial action in infected dentinal tubules compared with NaOCl (P < 0.05). The AgNp solution after 5 min was more effective in eliminating planktonic bacteria in dentinal tubules than in biofilm, but at 30 min fewer viable bacteria were observed in the biofilm compared with intratubular dentine (P < 0.05). CONCLUSIONS: AgNp irrigant was not as effective against E. faecalis compared to solutions commonly used in root canal treatment. NaOCl is appropriate as an irrigant because it was effective in disrupting biofilm and in eliminating bacteria in biofilms and in dentinal tubules.

Effectiveness of several solutions to prevent the formation of precipitate due to the interaction between sodium hypochlorite and chlorhexidine and its effect on bond strength of an epoxy-based sealer.

AIM: To evaluate the effectiveness of isopropyl alcohol, saline or distilled water to prevent the precipitate formed between sodium hypochlorite (NaOCl) and chlorhexidine (CHX) and its effect on the bond strength of an epoxy-based sealer in radicular dentine. METHODOLOGY: The root canals of 50 extracted human canines (n = 10) were instrumented. In G1, root canals were irrigated with 17% EDTA and 2.5% NaOCl; G2, as G1, except that 2% CHX was used as the final irrigant. In the other groups, intermediate flushes with isopropyl alcohol (G3), saline (G4) or distilled water (G5) were used between NaOCl and CHX. The specimens were submitted to SEM analysis to evaluate the presence of debris and smear layer, in the apical and cervical segments. In sequence, fifty extracted human canines were distributed into five groups (n = 10), similar to the SEM study. After root filling, the roots were sectioned transversally to obtain dentine slices, in the cervical, middle and apical thirds. The root filling was submitted to a push-out bond strength test using an electromechanical testing machine. Statistical analysis was performed using Kruskal-Wallis and Dunn's tests (α = 5%). RESULTS: All groups had similar amounts of residue precipitated on the canal walls (P > 0.05). The push-out bond strength values were similar for all groups, independently of the root third evaluated (P > 0.05). CONCLUSIONS: Isopropyl alcohol, saline and distilled water failed to prevent the precipitation of residues on canal walls following the use of NaOCl and CHX. The residues did not interfere with the push-out bond strength of the root filling.

SEM evaluation of the interface between filling and root-end filling materials.

The aim of this ex vivo study was to evaluate, by scanning electron microscopy (SEM), the presence of gaps at the interface between filling material and three root-end filling materials. Thirty human upper molars disto-buccal roots were instrumented and filled with gutta-percha and eugenol-based sealer. The apicoectomy was performed 2 mm from the apex and retrograde cavities were prepared with ultrasonic points (3 mm in deep). The samples were divided into three experimental groups (n = 10): Group I-white mineral trioxide aggregate (MTA); Group II-Super EBA; and Group III-Portland cement. The root-end filling materials were inserted into the retocavities using a MTA carrier. After 48 h, the roots were transversally sectioned in order to obtain the apical 5 mm. Next, each specimen was prepared longitudinally with crescent granulation of abrasives water-wet sandpapers in order to expose the filling and root-end filling materials. Then, the specimens were subjected to slow dehydration with silica gel, mounted onto specific stubs and coated with paladium coverage for SEM analysis of the interface between filling and root-end filling materials. The percentage of gaps at the interfacial area was calculated by using Image Tool 3.0 software. Super EBA presented the higher percentage of gaps (1.5 ± 0.67%), whereas MTA presented the lowest values (0.33 ± 0.20%; p = 0.0004). Despite the statistical differences observed between Super EBA and MTA, all the root-end filling materials presented great adaptation to the filling material, presenting small amount of gaps.

Evaluation of the propylene glycol association on some physical and chemical properties of mineral trioxide aggregate.

AIM: To evaluate the influence of propylene glycol (PG) on the flowability, setting time, pH and calcium ion release of mineral trioxide aggregate (MTA). METHODOLOGY: Mineral trioxide aggregate was mixed with different proportions of PG, as follows: group 1: MTA + 100% distilled water (DW); group 2: MTA + 80% DW and 20% PG; group 3: MTA + 50% DW and 50% PG; group 4: MTA + 20% DW and 80% PG; group 5: MTA + 100% PG. The ANSI/ADA No. 57 was followed for evaluating the flowability and the setting time was measured by using ASTM C266-08. For pH and calcium release analyses, 50 acrylic teeth with root-end cavities were filled with the materials (n = 10) and individually immersed in flasks containing 10 mL deionized water. After 3 h, 24 h, 72 h and 168 h, teeth were placed in new flasks and the water in which each specimen was immersed had its pH determined by a pH metre and the calcium release measured by an atomic absorption spectrophotometer with a calcium-specific hollow cathode lamp. Data were analysed by using one way anova test for global comparison and by using Tukey's test for individual comparisons. RESULTS: The highest value of flowability was observed with MTA + 20% DW and 80% PG and the lowest values were found with MTA + 100% DW. They were significantly different compared to the other groups (P < 0.05). The presence of PG did not affect the pH and calcium release. The MTA + 100% PG favoured the highest (P < 0.05) pH and calcium release after 3 h. Increasing the PG proportion interfered (P < 0.05) with the setting time; when used at the volume of 100% setting did not occur. CONCLUSION: The addition of PG to MTA-Angelus increased its setting time, improved flowability and increased the pH and calcium ion release during the initial post-mixing periods. The ratio of 80% DW­20% PG is recommended.

Evaluation of pH and calcium ion release of three root canal sealers.

The pH and calcium ion release of three root canal sealers--Sealapex, Sealer 26, and Apexit--were assessed at 24 and 48 hr, and at 7 and 30 days after spatulation. After manipulation, the sealers were placed in 1-cm-long tubes measuring 4 mm in diameter and immersed in a glass flask containing 10 ml of deionized water, which was hermetically sealed and stored at 37 degrees C. The tubes were removed at the scheduled times and the water in which they were immersed was tested for pH with a pHmeter and for released calcium by atomic absorption spectrophotometry. Starting 48 hr after immersion, Selapex produced an alklaine pH and released significantly higher calcium amounts compared with the other two sealers, with even more pronounced results after 30 days. On the basis of the results obtained, we conclude that Sealapex presented the highest calcium and hydroxyl release, especially after longer time intervals, whereas Sealer 26 showed highest release during the initial periods (i.e. during its setting time). Apexit presented the least satisfactory results.

[Perforating internal resorption of the root. Surgical treatment using a hybrid obturation technic]. / Reabsorção interna perfurante da raiz. Tratamento cirúrgico através da técnica híbrida de obturação.

This article relates a clinical case of internal root resorption with root perforation treated with a new surgical proceeding. The Tagger et alii technique was used for root canal filling and root resorption area.

[Restoration of a fractured anterior tooth with approximation of the fragment. Use of ionomeric cement with composite resin]. / Restauração de dente anterior fraturado com aproveitamento de fragmento. Emprego do cimento ionomérico associado à resina composta.

The authors present a clinical case of upper central incisor fractured, showing a alternative technic in which the fragment is firstly fixed with glass-ionomer cement to remnant tooth and then with a spherical diamond point the fractured line is ground off and filled up with composite resin.