Epoxy-based Sealer Research Articles

Effects of sisal nanofiber addition to epoxy resin-based sealer on its antibacterial power against Enterococcus faecalis

Sealer is one of root canal filler materials which has been developed and has an antibacterial agent to keep root canal sterile during and after an obturation process. This study aimed to find out the effect of sisal nanofiber addition to resin epoxy-based sealer on the antibacterial power against Enterococccus faecalis (E. faecalis) which is known as adaptive and potent bacteria which can be both aerobic and anaerobic. Sisal fibers were processed through many stages to make it nano sized (scouring, bleaching, neutralization, ultrasonification, and freeze-drying). Once nano-sized sisal fibers had been obtained, they were then mixed with sealer powder (AH26) in different concentrations: powder 0%, 0.25%, 0.5%, 0.75% and 1%. These concentrations were chosen based on preliminary research for reasonable contact angle measurement of sisal-sealer mixture. Antibacterial effect was examined using the diffusion method, each concentration was tested in 5 petri dishes which were planted with 1.5 X 108 CFU/ml E.faecalis bacteria. Each dish consisted of 5 holes (6 mm in diameter), each hole represented each concentration of nano sisal and sealer which were mixed until homogenous for 3 minutes before added to each hole. The dishes were then incubated for 48 hours at 37 °C. Inhibitory zones were measured, and analyzed using one-way ANOVA. The one-way ANOVA result showed that p=0.502 (p>0.05), meaning that the sisal nanofiber addition to epoxy resin-based sealer had no effect on E.faecalis inhibition. Thus, there was no effect of sisal nanofiber addition to epoxy resin-based sealer on E. faecalis.

A comparative evaluation of the sealing ability of two calcium silicate based sealers and a resin epoxy-based sealer through scanning electron microscopy and bond strength

Aim: this study aimed to compare the sealing ability of two types of commercially available calcium silicate bioceramic based root canal sealers and a resin based root canal sealer. Methods: Twenty one single-rooted teeth were used, samples (n= 21) were randomly divided into three groups according to the sealer used (group A; ADSEAL, group B; Wellroot, group C; Ceraseal). Roots were then cleaved longitudinally in the labiolingual direction; all samples were then sectioned at three, six, and nine mm from the root tip. The penetration of sealers into the dentinal tubules was examined at 1000x with a scanning electron microscope. Data were tested for normality using Shapiro Wilk test. ANOVA test was used for analyzing normally distributed data followed by Bonferroni post hoc test for pair-wise comparison. Significance level p≤0.001. Results: groups B and C showed better sealing ability than group A in all the three sections. The coronal section showed higher sealing ability than the middle section followed by the apical section in the three tested groups. Conclusion: it can be concluded that both calcium silicate-based sealers had better sealing ability and higher bond strength than the resin epoxy- based sealer.

Management of apical periodontitis using WaveOne gold reciprocating files, single-cone endodontic approach: A case series

IntroductionThe endodontic treatment of apical periodontitis (AP) without surgical intervention presents a unique clinical challenge. This case series aimed to test the changes in size of periapical lesion scale and healing in post-treatment of AP by cone beam computed tomography (CBCT) using Waveobe Gold reciprocating file with single cone treatment approach. Presentation of casesA total of 20 patients with 20 teeth (9 M, six premolars, one canine, and four incisors) with AP underwent CBCT scanning before and after non-surgical root canal treatment (NSRCT) or non-surgical retreatment (NSReTx). Standardized root canal chemo-debridement and instrumentation with WaveOne Gold (WOG) reciprocating files was used. The canals were obturated using epoxy-based sealer (AH Plus) with a single WaveOne Gold conform fit gutta-percha cone technique. After one year, assessment with CBCT images showed that the success and healing rate using (AH Plus) with single cone technique was very high. DiscussionApical periodontitis is an inflammatory disease at the root end of teeth. Following NSRCT or NSReTx, evaluation of lesion size by radiograph has been essential to the evaluation of lesions post-operatively. In addition to the absence of symptoms, complete restitution of the lamina dura and periodontal ligament (PDL) space on post-operative radiograph has been considered the optimal outcome success. ConclusionsWithin the limitations of this study, NSRCT or NSReTx using reciprocating WaveOne Gold and single cone with AH plus sealer resulted in healing of AP as assessed by CBCT.

Comparative Effect of Rotary Microbrush Combined with Different Chemical Irrigants on Root Dentin Microhardness, Roughness and Bond Strength to an Epoxy-based Sealer.

This study evaluated the effect of 17% EDTA, 10% citric acid (CA), and 2% chlorhexidine (CHX) activated with a rotary microbrush (CanalBrush) on root dentin microhardness, roughness, and epoxy-based sealer bond strength. One hundred sixty single-rooted bovine incisors were instrumented and divided into 8 groups according to treatment: 1. 17% EDTA; 2. 17% EDTA+2% CHX; 3. 10% CA; 4. 10% CA+2% CHX; 5. 17% EDTA with CanalBrush; 6. 17% EDTA+2% CHX with CanalBrush; 7. 10% CA with CanalBrush; and 8. 10% CA+2% CHX with CanalBrush. Ten roots in each group were split into halves and submitted to microhardness and roughness analyses (n = 10). Following endodontic filling with AH Plus sealer, 10 roots in each group underwent push-out bond strength testing (n = 10). Data were analyzed using two-way ANOVA and Tukey's tests (α = 0.05). All groups had similar microhardness values (p > 0.05) which was higher in the apical third than in the middle and cervical thirds (p < 0.05). The CanalBrush groups had higher roughness than the no-activation groups (p < 0.05), with significantly higher roughness in the cervical third than in the apical third (p < 0.05). All groups exhibited similar bond strength (p > 0.05), with the cervical third being higher, followed by the middle and apical thirds (p < 0.05). Microbrush activation had a direct impact on dentin roughness and did not influence the dentin microhardness or the retention of epoxy-based sealer to the root canal.

Effect of calcium silicate-based endodontic sealer on the retention of fiber posts cemented at different time intervals

ObjectiveTo evaluate the effect of BC HiFlow, a new calcium silicate-based endodontic sealer, compared with a resin epoxy-based sealer after 2 different times of cementation on the pull-out bond strength of glass-fiber–reinforced composite posts cemented with a self-adhesive resin cement (RelyX Unicem). MethodologySixty human maxillary central incisors were decoronated, prepared and obturated with gutta-percha and sealer. Roots were distributed into 5 groups according to the sealer and time of post cementation: (1) AH Plus sealer with immediate post fixation, (2) BC HiFlow with immediate post fixation, (3) AH Plus and post fixation after 7 days, (4) BC HiFlow and post fixation after 7 days, and (5) fiber post fixation in canals obturated with gutta-percha only (no sealer). After 1 week of post cementation, the pull-out test was performed and the failure mode was examined under a digital microscope. Data were analyzed using ANOVA followed by Tukey's post hoc and t tests (p < .05). ResultsWith immediate post cementation, AH Plus group showed significantly higher pull-out retentive strength than the BC HiFlow and control groups (p = .009 and p < .001, respectively). There was no significant difference between the groups when the posts were cemented 7 days after obturation (p = .726). The time of post cementation had a significant influence on the canals obturated with AH Plus (p = .003). The time did not significantly affect the canals obturated with BC HiFlow (p = .289). The prominent type of failure was mixed mode in all groups. ConclusionBC HiFlow sealer did not affect the pull-out bond strength of glass-fiber–reinforced composite posts cemented with a self-adhesive resin cement immediately after or 7 days after obturation. For immediate post cementation, AH Plus increased the pull-out bond in comparison to BC HiFlow.

Outcome of Root Canal Treatments Using a New Calcium Silicate Root Canal Sealer: A Non-Randomized Clinical Trial.

Background: The aim of this study was to compare the success rate of root canal treatments undertaken using a calcium silicate root canal sealer in combination with a single cone with non-calcium silicate cement and warm vertical condensation. Methods: 150 necrotic or pulpitic teeth were treated. (REC: 08/H0804/79). Following standardized root canal chemo-debridement. The canals were obturated using warm vertical condensation of gutta-percha and epoxy-based sealer (AH plus) or a calcium silicate sealer (BioRootTM RCS) with a single cone technique. Follow-up assessment was conducted at 12 months using Cone Beam Computed Tomography (CBCT). Results: At 1-year recall, 104 teeth were assessed (51 AH plus, 53 BioRootTM RCS). The success rate using loose criteria for the CBCT images and PA radiographs was respectively 80% and 89% in the AH plus/warm vertical condensation group, 84% and 90% in the BioRootTM RCS/single cone group. There was no statistically significant difference between the two groups (Fisher exact test p value 0.6099 for the CBCT images). Conclusion: Within the limitations of this non-randomized trial, a calcium silicate cement in combination with single cone resulted in a similar proportion of successful cases compared to warm vertical condensation and epoxy-based sealer.

1064-nm Nd:YAG and 980-nm Diode Laser EDTA Agitation on the Retention of an Epoxy-Based Sealer to Root Dentin.

Root canal irrigants are used to minimize the negative effects of smear layer on endodontic sealer retention. The aim of this study was to evaluate the efficacy of agitation of 17% ethylenediaminetetraacetic acid (EDTA) with ultrasonic, 1064-nm Nd:YAG and 980-nm diode laser on the retention of an epoxy-based sealer to the root canal walls. Forty single-rooted bovine teeth were instrumented with ProTaper rotary system and divided into four groups according to the final irrigation protocol (n = 10): (1) 17% EDTA (control); (2) 17% EDTA with 50-s ultrasonic agitation; (3) 17% EDTA with 50-s diode laser (2-W) agitation; and (4) 17% EDTA with 50-s Nd:YAG (1.5-W) laser agitation. After endodontic filling with gutta-percha F5 master cone and Sealer 26, the roots were sectioned at the cervical, middle, and apical root thirds to obtain 1.5-mm slices. Push-out tests were performed using a universal testing machine at a 1 mm/min crosshead speed. Data were analyzed using two-way ANOVA and Tukey's tests (α=0.05). Apical root thirds had significant higher retention values than cervical and middle thirds (p < 0.05). EDTA with 1064-nm Nd:YAG or 980-nm diode laser presented the highest retention values and was significantly different from EDTA with ultrasonic agitation and EDTA only (p < 0.05). Adhesive failures were predominant to EDTA only group. Mixed failures were predominant to all agitation groups. 1064-nm Nd:YAG and 980-nm diode laser EDTA agitation enhanced the retention of the epoxy-based sealer to the root canal walls compared with that due to EDTA only or EDTA with ultrasonic agitation.

Effect of sodium hypochlorite irrigation with or without surfactants on the bond strength of an epoxy-based sealer to dentin.

This study evaluated the effect of sodium hypochlorite (NaOCl) irrigation with or without surfactants on the bond strength of an epoxy-based sealer to the root canal dentin. Eighty decoronated single-rooted human mandibular premolars were instrumented using the rotary system. The roots were subsequently rinsed with 5ml 17% EDTA for 1min and then randomly divided into 3 test groups (n=20) and 1 control group (n=20) according to the type of irrigation with experimental 5% NaOCl (Wizard, RehberKimya, Istanbul, Turkey) solutions: Group 1: NaOCl-0.1% benzalkonium chloride; Group 2: NaOCl-0.1% Tween 80; Group 3: NaOCl-0.1% Triton X-100; control group: NaOCl without any surfactants. Five samples from each group were prepared for scanning electron microscopy to examine the surface of root canal dentin. The 15 samples remaining in each group were obturated with gutta-percha and AH Plus (Dentsply DeTrey GmbH, Konstanz, Germany) using the cold lateral compaction technique. A push-out test was used to measure the bond strength between the sealer and root canal dentin. Data were analyzed using two-way analysis of variance and Tukey's post hoc tests (P=0.05). The NaOCl-0.1% Triton X-100 group demonstrated the highest mean bond-strength values in all root thirds among the groups (P<0.05). However, the bond strength of the sealer in the NaOCl-0.1% benzalkonium chloride and NaOCl-0.1% Tween 80 groups did not differ from that in the control group (P>0.05). Additionally, the bond-strength values decreased in the corono-apical direction for all groups (P<0.05). NaOCl solution with Triton X-100 can provide higher bond strength of the epoxy resin-based sealer to root dentin compared to NaOCl solution wiithout any surfactant. The bond strength of sealer to dentin can be improved by the addition of the surfactants to NaOCl solution.

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.

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. 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%). 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). 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.

The impact of the addition of iodoform on the physicochemical properties of an epoxy-based endodontic sealer

Due to the low radiopacity of Sealer 26, iodoform is frequently empirically added to this sealer. Thus, the interference of this procedure with the physicochemical properties of Sealer 26 must be evaluated.Objective This study evaluated the influence of the addition of iodoform on setting time, flow, solubility, pH, and calcium release of an epoxy-based sealer. Material and Methods The control group was pure Sealer 26, and the experimental groups were Sealer 26 added with 1.1 g, 0.55 g or 0.275 g of iodoform. Setting time evaluation was performed in accordance with the ASTM C266-03 speciflcation. The analysis of flow and solubility was in accordance with the ISO 6876-2001 speciflcation. For the evaluation of pH and calcium ion release, polyethylene tubes were filled with the materials and immersed in flasks with 10 ml of deionized water. After 24 h, 7, 14, 21, 28, and 45 days pH was measured. In 45 days, the calcium released was evaluated with an atomic absorption spectrophotometer. Results The addition of iodoform increased setting time in comparison with pure sealer (P<0.05). As for flow, solubility, and calcium release, the mixtures presented results similar to pure sealer (p>0.05). In the 24 h period, the mixture with 1.1 g and 0.55 g of iodoform showed lower pH than pure sealer and than sealer added with 0.275 g of iodoform (P<0.05). Conclusions The iodoform added to Sealer 26 interferes with its setting time and solubility properties. Further studies are needed to address the clinical signiflcance of this interference.

Accelerated laboratory evaluation of surface treatments for protecting concrete bridge decks from salt scaling

In this accelerated laboratory study, several commercial products of surface treatment were included in the test program, including three concrete sealers, two crack sealants, and two water repellents. To characterize the product longevity under traffic, the abrasion resistance of concrete treated by each product was tested. To characterize the product effectiveness against salt scaling, the surface treated concrete cylinders were subjected to the joint action of 15 freeze/thaw and wet/dry cycles and exposure to a diluted deicer simulated by 3wt.% NaCl solution. The mass loss of these concrete cylinders during the freeze/thaw cycles was periodically measured. For mechanistic investigation, the surface-treated concrete specimens were further tested for their water absorption rates, gas permeability, and water contact angle. For all the laboratory tests, the untreated concrete was used as control. The results confirmed the benefits of using these products to treat the surface of concrete against salt scaling, as all of them exhibited outstanding performance and reduced the mass loss of the concrete by 90% or more. Among them, two products (epoxy-based sealer T48CS and water repellent ATS-42) exhibited the best performance in protecting the concrete from salt scaling and featured the highest resistance to abrasion and generally lower water absorption rates and gas permeability coefficients. The results suggest that high resistance to both gas and water penetration is a crucial property in a good surface sealer, crack sealant or water repellent applied to concrete.

Evaluation of the interaction between sodium hypochlorite and several formulations containing chlorhexidine and its effect on the radicular dentin—SEM and push‐out bond strength analysis

The aim of the current study was to evaluate the presence of debris and smear layer after endodontic irrigation with different formulations of 2% chlorhexidine gluconate (CHX) and its effects on the push-out bond strength of an epoxy-based sealer on the radicular dentin. One hundred extracted human canines were prepared to F5 instrument and irrigated with 2.5% sodium hypochlorite and 17% ethylenediaminetetraacetic acid. Fifty teeth were divided into five groups (n = 10), according to the final irrigation protocol with different 2% CHX formulations: G1 (control, no final rinse irrigation), G2 (CHX solution), G3 (CHX gel), G4 (Concepsis), and G5 (CHX Plus). In sequence, the specimens were submitted to scanning electron microscopy (SEM) analysis, in the cervical-medium and medium-apical segments, to evaluate the presence of debris and smear layer. The other 50 teeth were treated equally to a SEM study, but with the root canals filled with an epoxy-based endodontic sealer and submitted to a push-out bond strength test, in the cervical, middle, and apical thirds. G2, G3, G4, and G5 provided higher precipitation of the debris and smear layer than G1 (P < 0.05), but these groups were similar to each other (P > 0.05), in both segments. The values obtained in the push out test did not differ between groups, independent of the radicular third (P > 0.05). The CHXs formulations caused precipitation of the debris and smear layer on the radicular dentin, but these residues did not interfere in the push-out bond strength of the epoxy-based sealer.

Effect of the root canal final rinse protocols on the debris and smear layer removal and on the push‐out strength of an epoxy‐based sealer

The aim of the present study was to evaluate the efficacy of QMiX, SmearClear, and 17% EDTA for the debris and smear layer removal from the root canal and its effects on the push-out bond strength of an epoxy-based sealer by scanning electron microscopy (SEM). Forty extracted human canines (n = 10) were assigned to the following final rinse protocols: G1-distilled water (control), G2-17% EDTA, G3-SmearClear, and G4-QMiX. The specimens were submitted to a SEM analysis to evaluate the presence of debris and smear layer, respectively, in the apical or cervical segments. In sequence, forty extracted human maxillary canines with the root canals instrumented were divided into four groups (n = 10) similar to the SEM analysis study. After the filling with AH Plus, the roots were transversally sectioned to obtain dentinal slices. The specimens were submitted to a push-out bond strength test using an electromechanical testing machine. The statistical analysis for the SEM and push-out bond strength studies were performed using the Kruskal-Wallis and Dunn tests (α = 5%). There was no difference among the G2, G3, and G4 efficacy in removing the debris and smear layer (P > 0.05). The efficacy of these groups was superior to the control group. The push-out bond strength values of G2, G3, and G4 were superior to the control group. The ability to remove the debris and smear layer by SmearClear and QMiX was as effective as the 17% EDTA. The final rinse with these solutions promoted similar push-out bond strength values.

Behavior of resin-based endodontic sealer cements in thin and thick films

ObjectivesFor root canal fillings, a thin layer of sealer cement is generally recommended. However, with resin-based sealers, lower bond strength to dentin has been shown in thin layers compared to thick, contrary to typical behavior of adhesive layers between two adherents. The aim of this study was to evaluate tensile and shear bond strength of thin and thick films of three resin-based sealers (one epoxy-based and two methacrylate-based) materials and to investigate corner effects of one methacrylate-based resin sealer. MethodsFreshly mixed sealer cements were placed between metal-to-metal surfaces of plano-parallel stainless steel aligned rods with diameter 4.7mm. Ten samples were prepared for each type, thickness (0.1 and 1.0mm) of sealer and test. Tensile and shear strengths were measured after 48h for the methacrylate-based materials and after 7days for the epoxy-based material using a universal testing machine at a crosshead speed of 1mm/min. Corner effects were investigated using one methacrylate-based resin material. ResultsFilm thickness had a highly significant influence on both tensile and shear strengths. For methacrylate resin-based sealers, thin films had higher bond strength than thick (p<0.001 for both tensile and shear bond strength). With the epoxy-based sealer either no difference (shear) or lower bond strength in thin films (tensile; p<0.05) was found, and appeared to result from numerous voids created during mixing. The methacrylate based sealer demonstrated typical engineering behavior for an adhesive material, with corner effects shown as a material property and in good agreement with the tensile bond strength results. SignificanceThe higher tensile and shear bond strength of resin-based sealer in thin films is the opposite of that previously reported for bonding to dentin. The substrate clearly has an important role in failure behavior.

Ex vivo study of the adhesion of an epoxy‐based sealer to human dentine submitted to irradiation with Er : YAG and Nd : YAG lasers

To evaluate the adhesion of an epoxy-based sealer to human dentine submitted to irradiation with Er : YAG or Nd : YAG laser at various parameters. Ninety maxillary canine teeth were sectioned transversely at the cemento-enamel junction and at the root tip to leave an 8-mm-long cylinder. The tooth specimen was centred in a metallic ring (16 mm diameter and 8 mm height) and embedded in acrylic resin. The root canals were prepared using a low-speed handpiece and a conical diamond bur, which was attached to a paralleling device. This bur was lowered to a depth previously determined by a silicone stop. Specimens were divided into nine groups: group I, dentine was treated with 2 mL of 17% EDTAC for 5 min. Groups II-V were irradiated with Er : YAG laser at the following parameters: group II - 8 Hz and 200 mJ input (120 mJ output); group III - 8 Hz and 400 mJ input (240 mJ output); group IV - 16 Hz and 200 mJ input (120 mJ output); group V - 16 Hz and 400 mJ input (240 mJ output). Groups VI-IX were irradiated with Nd : YAG laser at the following parameters: group VI - 10 Hz and 1 W input (0.4 W output); group VII - 10 Hz and 2 W input (0.8 W output); group VIII - 15 Hz and 1 W input (0.4 W output); group IX - 15 Hz and 2 W input (0.8 W output). The root canals were filled with an epoxy-based root canal sealer and submitted to a push-out test. Statistical analysis showed significant differences (P < 0.01) between Er : YAG and Nd : YAG laser treatments at the higher frequencies compared with 17% EDTAC. Greater adhesion values were obtained for groups IV and V (Er : YAG laser) and groups VIII and IX (Nd : YAG laser), which were statistically different from groups II and III (Er : YAG laser) and groups VI and VII (Nd : YAG laser). Treatment with only 17% EDTAC had the lowest adhesion values. An increase in frequency, independent of power settings, of the lasers used in this study increased adhesion of an epoxy-based root canal sealer.