Biocompatibility of four root canal sealers: a histopathological evaluation in rat subcutaneous connective tissue

Chemical, Antibacterial, and Cytotoxic Properties of Four Different Endodontic Sealer Leachates Over Time

INTRODUCTION

The management of apical periodontitis involves the elimination of bacteria to achieve healing of the periapical tissues. To this end, understanding of the antimicrobial properties and cytotoxicity of root canal sealers over time is important. This study aimed to assess the cytocompatibility and antibacterial activity of leachates obtained from selected endodontic sealers.

METHODS

Four sealers were used in this study; AH Plus, an epoxy resin-based sealer, and three hydraulic calcium silicate-based sealers: AH Plus Bioceramic, BioRoot RCS, and BioRoot Flow. Sealer chemistry was assessed by scanning electron microscopy and energy dispersive spectrum analysis. Leachates of the tested sealers were prepared by immersing sealer discs in Hank's balanced salt solution for 28 and 90 days. Element release was assessed using inductively coupled plasma mass spectroscopy. Enterococcus faecalis and Fusobacterium nucleatum were exposed to the leachates followed by colony-forming unit determination, and the human osteoblast-like cell line Saos-2 was assessed with regard to cell death, caspase expression and activity of alkaline phosphatase (ALP) after stimulation with the leachates.

RESULTS

Calcium leaching was detected in the tricalcium silicate-based sealers, which increased the leachate pH significantly (P < .0001). AH Plus Bioceramic leachate displayed antimicrobial activity at 28 days against E. faecalis (P < .01). ALP levels were reduced in response to AH Plus Bioceramic and BioRoot RCS 1-day leachates (P < .05). High cell viability was observed after exposure to all sealers.

CONCLUSIONS

The leachates of the tested sealers were cytocompatible; however, their antimicrobial activity as well as their potential to induce the bone formation marker ALP was minimal.

The status of clinical trials regarding root canal sealers

Objectives

This study aimed to present the results and analyses of clinical trials, including updates on the different functions of root canal sealers.

Materials and Methods

In June 2023, we performed a comprehensive search of ClinicalTrials.gov to identify interventional clinical trials pertaining to root canal sealers. In total, 23 clinical trials conducted up to June 2023 were included in this study.

Results

Approximately half of the trials (11 out of 23) were completed, while none were terminated or withdrawn. Each included trial had a minimum of 10 participants, with 11 trials having more than 100 participants. None of the assessed trials provided outcomes, and the majority (17 out of 23) lacked associated publications. In terms of geographic distribution, the USA and Canada did not contribute to any root canal sealer trials.

Conclusions

This study highlights the lack of diversity in trial locations, the absence of reported results, and a scarcity of clinical trials examining the physicochemical properties of different sealers. Most published trials primarily focused on assessing the post-operative pain effect of these sealers, but no significant difference was found regarding post-operative pain control.

Subcutaneous tissue reaction to a novel nano zinc oxide eugenol dental cement

BACKGROUND

Zinc oxide eugenol (ZOE) cement is a popular dental material due mainly to its analgesic, antibacterial and anti-inflammatory effects. The formulation of ZOE cement from nano particle-sized zinc oxide (ZnO) has the potential to increase these properties as well as reduce its adverse effects to the surrounding tissues.

OBJECTIVE

This study evaluated the subcutaneous tissue response towards nano ZOE cements (ZOE-A and ZOE-B) in comparison to conventional ZOE (ZOE-K).

METHODS

Test materials were implanted into 15 New Zealand white rabbits. Tissue samples were obtained after 7, 14, and 30 days (n = 5 per period) for histopathological evaluation of inflammatory cell infiltrate, fibrous tissue condensation, and abscess formation.

RESULTS

ZOE-A showed the lowest score for the variable macrophage and lymphocyte at day 7. Both ZOE-A and ZOE-B presented lower fibrous tissue condensation and abscess formation compared to conventional ZOE-K. By day 30, ZOE-A exhibited less lymphocytic and neutrophilic infiltrate compared to the other materials, while ZOE-B had the lowest score for macrophages. ZOE-K exerted higher inflammatory cell response at almost all of the experimental periods. All of the materials resulted in thin fiber condensation after 30 days.

CONCLUSIONS

Rabbit tissue implanted with ZOE-A and ZOE-B showed better response compared to ZOE-K.

Biocompatibility of three different root canal sealers, experimental study

OBJECTIVES

This study was assessed the biocompatibility of three different root canal sealers (Well-Root St, GuttaFlow Bioseal, and AH-Plus) following implantation in rat subcutaneous tissues, using histopathological immunohistochemical analysis.

METHODS

Four groups of eighty-four male rats each underwent subcutaneous dorsal implantation of a polyethylene tube, either empty or filled. Tissues were collected, fixed, and processed for histological analysis after 7, 15, and 30 d. Slides were photographed and digitally processed to identify lymphocytes and macrophages using Cluster of differentiation 3 (CD3) and cluster of differentiation 68 (CD68) markers, respectively. P was set at 0.05, when lymphocyte and macrophage infiltration was compared between groups and observation times using one-way analysis of variance (ANOVA).

RESULTS

Histopathological analysis of all groups revealed an inflammatory reaction followed by the emergence of a fibrous capsule after 7 days. After 30 days, the thickness of the fibrous capsule and the inflammatory response subsided. CD3 staining for immunohistochemical analysis revealed that the AH-Plus group had the highest mean percentage of lymphocyte infiltration at 7 and 15 days, followed by the Well-Root St, GuttaFlow Bioseal, and Control groups. After 30 days, no discernible difference was observed between the groups in terms of the mean percentage of lymphocyte infiltration. After 7, 15, and 30 days, there was a significant difference in the mean percentage of macrophage infiltration across the groups, as demonstrated by CD68 staining. After 7, 15, and 30 days, the AH-Plus group had the highest mean percentage of macrophage infiltration, followed by the Well-Root St. and GuttaFlow Bioseal groups, while the control group had the lowest mean percentage.

CONCLUSION

All observational periods showed minimal inflammatory reactions to GuttaFlow Bioseal. After subcutaneous tissue implantation in a rat model, the initial inflammatory reactions to Well-Root St and AH-Plus had abated by day 30, and all tested sealers had outstanding biocompatibility.

Biocompatibility in vivo of elastic cartilage treated in alkaline solutions

ABSTRACT This study verified the in vivo biocompatibility of bovine elastic cartilage decellularized with alkaline solution in relation to the non-decellularized cartilage implanted in rats. Fifty Wistar rats were divided into two groups, with the experimental group (EG) receiving subcutaneous implants of cartilage treated in alkaline solution and the control group (CG) receiving subcutaneous implants of untreated cartilage. In both groups, the implants were removed on days 3, 7, 14, 21 and 42 with the preparation of histological slides stained with Hematoxylin and Eosin for the quantification of inflammatory cells, fibroblasts, angiogenesis, and cartilage degradation. The results showed that EG presented a less intense inflammatory infiltrate and better organization of collagen fibers compared to CG. It was concluded that the alkaline treatment provided better biocompatibility for elastic cartilage when implanted subcutaneously in rats.

Subcutaneous tissue reaction and gene expression of inflammatory markers after Biodentine and MTA implantation

The aim of this study was to evaluate the subcutaneous connective tissue response of isogenic mice exposed to tricalcium silicate (Biodentine) and aggregated mineral trioxide (ProRoot MTA). A total of 120 mice were divided into 4 groups in 3 different experimental periods (7, 21 and 63 days): Biodentine; Pro-Root MTA; zinc oxide-eugenol and; Negative control - Sham. After the experimental periods microscopic descriptive, semi-quantitative and quantitative analysis of the inflammatory process were analyzed on H&E sections and evaluation of the gene expression of Il10, Infg, Il6, Il1r1 and Tnf (qRT-PCR) were performed. The data obtained were analyzed using the chi-square test and two-way analysis of variance (ANOVA) followed by the Bonferroni post-test (5% significance level). Results: In the microscopic analysis, a slight inflammatory infiltrate was observed, with a predominance of sparse macrophages and polymorphonuclear cells, slight tissue fibrosis, regular fibrous capsule and with dystrophic calcifications, in all groups that received the materials (Biodentine and Pro-Root MTA). In parallel, all materials modulated the gene expression of the different cytokines and receptors evaluated. Conclusion: Pro-Root MTA and Biodentine showed a tissue compatibility, mediated inflammation, with increased fibrous tissue and production of pro- and anti-inflammatory cytokines.

The effect of changing apical foramen diameter on regenerative potential of mature teeth with necrotic pulp and apical periodontitis

OBJECTIVE

The aim of the present study was to evaluate the regenerative potential of permanent necrotic mature teeth with different apical foramen diameters in comparison to conventional endodontic treatment.

METHODS

Pulp necrosis and periapical pathosis were induced in premolars (144 roots) in six mongrel dogs. The infected teeth were divided into six groups; conventional root canal treatment (RCT) group prepared up to apical preparation sizes #F3 ProTaper file, regenerative endodontic therapy (RET) groups; groups RET-F3, RET-F4, and RET-F5 where regenerative endodontic procedures were applied after apical preparation up to sizes #F3, F4, and F5 ProTaper file, respectively, control groups; and positive (P) and negative (N) groups included infected and healthy teeth respectively. Each group (12 teeth with 24 roots each) was further subdivided into two subgroups (6 teeth with 12 roots each) according to the evaluation periods 1 and 3 months; each group was equally randomized in the upper and lower jaws during each evaluation period.

RESULTS

The inflammatory cell counts for the RCT group were statistically significantly higher than that of all RET groups at the first period and only significantly higher than RET-F5 at the second period. The enlargement of the apical foramen to #F5 showed no statistically significant difference with #F4 regarding the inflammatory cell count, tissue in-growth inside the root canal, and percentage of bone resorption. The tissue formed after RET was not true pulp tissue and is considered tissue repair with connective tissue, dilated blood vessels, and cementum-like structures.  CONCLUSION: Increasing the apical size diameter was associated with less inflammatory cell count, less percentage of bone resorption, more tissue ingrowth, and more percentage of new hard tissue formation inside root canal. The minimum apical diameter that should be enlarged for RET is 0.4 mm.

CLINICAL RELEVANCE

RET could be used as an alternative procedure to RCT for the treatment of mature teeth with necrotic pulp and apical periodontitis.

Evaluation of tissue inflammatory response of four intracanal medicament - An animal study

Aim:

The aim of the study was to evaluate the tissue inflammatory response of origanum vulgarae, omeprazole, triple antibiotic paste (TAP), and calcium hydroxide in an animal model.

Materials and Methods:

Seventy Five male Wistar rats were randomly divided into four experimental groups and one control group: Group 1: control (n = 15), Group 2: 0.25 mg origanum vulgarae/1 ml of cellulose (n = 15), Group 3: 2 mg omeprazole/1 ml of distilled water (n = 15), and Group 4: 1 mg TAP/1 ml of distilled water (n = 15), Group 5: 16 mg calcium hydroxide/1 ml of distilled water (n = 15). A trough was made in the periapical bone and the medicament of the respective groups was placed. After the 7^th, 14^th, 28^th and days, the animals were euthanized and tissue specimen was prepared for histological examination.

Results:

The results were analyzed statistically. On the 7^th and 14^th days, all the experimental groups showed severe inflammatory response with no statistical significance, whereas on the 28^th day, the inflammatory response was graded based on the mean value, in which omeprazole showed moderate inflammatory cells followed by TAP. Mild inflammatory response was seen in calcium hydroxide and origanum vulgarae, showing no statistical significance.

Conclusion:

Within the limitation of the study, severe inflammatory response was reported on the 7^th and 14^th days in all experimental groups, whereas on 28^th day, there was a moderate inflammatory response seen in omeprazole, followed by TAP. Calcium hydroxide and origanum vulgarae showed a mild inflammatory response.

Biocompatibility and immunolabeling of fibronectin and tenascin of resinous root canal sealersw

Aims:

The aim of this study was to evaluate the biocompatibility of resinous root canal sealers: Sealer 26, AH plus, and SK Seal Root Canal Sealer in the subcutaneous tissue of rats.

Subjects and Methods:

Twenty-four Wistar rats received polyethylene tubes containing the sealers and empty tubes as control (n = 6). After 7, 15, 30, and 60 days, animals were killed and polyethylene tubes were removed with the surrounding tissues. The specimens were embedded in paraffin, processed for hematoxylin-eosin and immunohistochemistry assessed for fibronectin (FN) and tenascin (TN).

Statistical Analysis Used:

Data were tabulated and analyzed via Kruskal–Wallis and Dunn's test (P < 0.05).

Results:

All groups induced a moderate inflammatory reaction after 7 and 15 days (P > 0.05); after 30 days, a mild inflammatory infiltrate was observed in control groups, and moderate in sealers groups (P > 0.05); all groups showed mild inflammatory infiltrate at 60 days (P > 0.05). Overall, the fibrous capsule was considered thick only on the 7^th day and became thin over time. All groups had expression for FN and TN in all analyzed periods, with high immunolabeling in sealers groups when comparing with the control group (P < 0.05).

Conclusion:

All sealers demonstrated biocompatibility and induced FN and TN expression.

Egyptian Propolis-Loaded Nanoparticles as a Root Canal Nanosealer: Sealing Ability and in vivo Biocompatibility

Background

Successful endodontic therapy is mainly governed by the satisfactory sealing ability of the applied root canal sealer. Also, tolerability of root canal structure to accommodate the presence of a sealer participates in the efficiency of the treatment. Hence, this study was aimed to extrapolate our previous one that was concerned with the preparation and evaluation of novel nature-based root canal sealers. Our current work is focused on the evaluation of sealing ability and in vivo biocompatibility.

Materials and Methods

Egyptian propolis was extracted (ProE) and encapsulated in polymeric nanoparticles (ProE-loaded NPs). Two root sealers, PE sealer and PE nanosealer, were fabricated by incorporating ProE and ProE-loaded NPs, respectively. The sealing ability of the developed sealers was tested by a dye extraction method. An in vivo biocompatibility study was conducted using a subcutaneous implantation method for two and four weeks. At the same time, a model sealer (AH Plus®) was subjected to the same procedures to enable accurate and equitable results.

Results

The teeth treated with PE sealer exhibited weak sealing ability which did not differ from that of unfilled teeth. PE nanosealer enhanced the sealing ability similarly to the model sealer with minimal apical microleakage. Studying in vivo biocompatibility indicated the capability of the three tested sealers to induce cell proliferation and tissue healing. However, PE nanosealer had superior biocompatibility, with higher potential for cell regeneration and tissue proliferation.

Conclusion

PE nanosealer can be presented as an innovative root canal sealer, with enhanced sealing ability as well as in vivo biocompatibility. It can be applied as a substitute for the currently available sealers that demonstrate hazardous effects.

Antibacterial Effect of Curcumin against Clinically Isolated Porphyromonas gingivalis and Connective Tissue Reactions to Curcumin Gel in the Subcutaneous Tissue of Rats

The aim of this study was to find the antibacterial potential of curcumin against Porphyromonas gingivalis and connective tissue responses to curcumin gel in the subcutaneous tissue of rats. The sample consisted of subgingival plaque collected from patients with chronic periodontitis. The P. gingivalis clinically isolated strain was confirmed by anaerobic culture, morphology, biochemical tests (Vitek ANC Kit), and PCR (16S rDNA). Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by incubation of twofold serial dilution of broth media containing curcumin (from 100 to 0.05 µg/ml) for 48 h at 37°C. Fifteen adult Wistar rats (3-4 months old) were used and randomly divided into three groups (negative control, positive control, and experimental groups). Tubes were implanted on the back skin (45 tubes). Rats were euthanized at 7, 30, and 60 days after surgical processes, and then the samples were taken and processed to achieve conventional hematoxylin and eosin-stained slides. The MIC and MBC of curcumin against clinically isolated P. gingivalis were 12 µg/ml. Curcumin gel caused moderate inflammatory reactions at 7 and 30 days, while at 60 days, it caused dramatic decline and resulted in a nonsignificant response. Besides, curcumin gel stimulated quick reepithelialization, fibroblast proliferation, and scarring through the formation of thick bundles of well-organized collagen fibers. Curcumin has an effective antibacterial action against clinically isolated P. gingivalis at low concentration (12 µg/ml), and it was regarded as the biocompatible material in the subcutaneous tissues.

Biocompatibility and biomineralization assessment of mineral trioxide aggregate flow

OBJECTIVE

Evaluate, in vivo, the biocompatibility via subcutaneous inflammatory tissue response and mineralization ability of the new MTA Flow compared to MTA Angelus and ProRoot MTA.

MATERIALS AND METHODS

Forty male Wistar rats were assigned and received subcutaneous polyethylene tube implants containing the test materials and a control group with empty tube (n = 10 animals/group). After days 7, 15, 30, and 60, the animals were euthanized and the polyethylene tubes were removed with the surrounding tissues. Inflammatory infiltrate and thickness of the fibrous capsule were histologically evaluated. Mineralization was analyzed by Von Kossa staining and under polarized light. Data were analyzed via Kruskal-Wallis and Dunn's test with a significance level of 5%.

RESULTS

MTA Angelus induced the mildest reaction after 7 (P > .05) and 15 days (P < .05) followed by MTA Flow, both cements achieving mild inflammatory reaction after 15 days. ProRoot MTA induced a severe inflammation on day 7 and was reducing after day 15 (P > .05). No difference was observed after days 30 or 60 (P > .05). Von Kossa staining and birefringent structures were positive to all materials.

CONCLUSIONS

At the end of the experiment, the novel MTA Flow showed biocompatibility and induced biomineralization in all time periods.

CLINICAL RELEVANCE

The final consistence obtained in MTA Flow may facilitate several procedures, indicating that the MTA Flow has a promising application in endodontics.

Cytotoxicity, Biocompatibility, and Biomineralization of the New High-plasticity MTA Material

INTRODUCTION

Mineral trioxide aggregate (MTA) has excellent biological properties, but its handling properties have been criticized for both ProRoot MTA (Tulsa Dental Products, Tulsa, OK) and white MTA-Angelus (MTA-Ang; Angelus Indústria de Produtos Odontológicos S/A, Londrina, PR, Brazil). Angelus MTA HP (high plasticity) (Angelus Indústria de Produtos Odontológicos S/A) has been introduced recently. Considering the importance of biological properties of materials that will be in contact with the tissues, this study evaluated the cytotoxicity, biocompatibility, and biomineralization of MTA HP compared with white MTA-Ang.

METHODS

L929 fibroblast cell lines were cultured, and cell viability was assessed at 6, 24, 48, and 72 hours using the alamar Blue assay (Thermo Fisher Scientific, Waltham, MA). A subcutaneous implant test was performed with polyethylene tubes containing 1 of the materials or empty tubes (control) using 20 Wistar rats. After 7 and 30 days of implantation, the tubes with surrounding tissues were removed for analysis using hematoxylin-eosin or von Kossa stain or they remained unstained for observation under polarized light. The results were statistically analyzed (P < .05).

RESULTS

A significant increase in cell viability for MTA HP was observed after 24, 48, and 72 hours compared with the control (P < .05). At 72 hours, MTA HP exhibited a higher viability compared with white MTA-Ang (P < .05). Histologic analysis performed at 7 days showed moderate inflammation and a thick fibrous capsule in all groups (P > .05). At 30 days, mild inflammation and a thin fibrous capsule were observed in all groups (P > .05). All materials had structures positive for von Kossa and birefringent to polarized light.

CONCLUSIONS

MTA HP showed biocompatibility and biomineralization similar to MTA-Ang. In addition, MTA HP showed increased fibroblast cell viability compared with white MTA-Ang after a longer period.

Biocompatibility of a calcium hydroxide-propolis experimental paste in rat subcutaneous tissue

Intracanal medications are fundamental for disinfection of the root canal system and participate in periapical repair, so their biocompatibility is of utmost importance to avoid tissue damage. This study evaluated the biocompatibility of a experimental paste of calcium hydroxide and propolis in the subcutaneous tissue of rats. The study was conducted on 15 male Wistar rats. Two incisions were made on the dorsal region of each animal for introduction of 4 tubes: one tube was empty; one contained zinc oxide-eugenol cement, and the two other tubes were filled with experimental paste. After 7, 14 and 30 days, the animals were euthanized and the specimens were subjected to histotechnical preparation. The hematoxylin and eosin-stained histological sections were analyzed by light microscopy. Scores were established according to the inflammatory process and statistically compared by the Tukey test (α = 5%). The analysis of histological sections showed non-significant or mild inflammatory reaction in the connective tissue in contact with the empty tubes in all study periods while the contact of subcutaneous tissue with zinc oxide-eugenol elicited moderate or severe inflammation similarly without significant difference among the study periods. The connective tissue was moderately inflamed at 7 days when contacting the experimental paste, but the inflammatory process was non-significant or mild at 14 and 30 days. The experimental paste was biocompatible with the tissues after 14 days of subcutaneous implantation.

Tissue Reaction to Different Types of Calcium Hydroxide Paste in Rat

The purpose of this study was to compare the biocompatibility of two types of calcium hydroxide paste in subcutaneous tissue in rat. Twenty-two Wistar rats were divided into 4 experimental (n=5 each) and one control (n=2) group. A polyethylene tube filled with either Dentsply or Sure-Paste was implanted in each rat in the experimental groups, while an empty polyethylene tube was used in the control group. After 15 or 60 days, the animals were sacrificed and histopathological examination carried out. Tissue reaction was assessed by inflammatory cell infiltration using a 4-point scoring system, ranging from 0 to 3. Data were analyzed with the Kruskal-Wallis, Wilcoxon, and McNemar tests. Both types of paste induced an inflammatory response at each time point, although the intensity varied. A significant reduction in the number of inflammatory cells was observed at 60 days. Dentsply appeared to induce a more marked inflammatory response at both time points, although the difference was not significant. These results suggest that both types of paste are biocompatible with subcutaneous tissue in rat.

Biocompatibility of a new epoxy resin-based root canal sealer in subcutaneous tissue of rat

Objective:

The objective was to evaluate the subcutaneous biocompatibility of two root canal sealers.

Materials and Methods:

Thirty female rats were distributed into two groups of 15 animals. Each received subcutaneous dorsal implants: Silicone tubes filled with AH Plus or Obtuseal. After the 11^th, 14^th, and 45^th days, tissues were collected for biopsy and fixed and processed for histologic evaluation. Observations of the cellular inflammatory components, such as lymphocytes and macrophages, were made. The data were analyzed using Kruskal–Wallis and Connover tests (P < 0.05).

Results:

By the 7^th day, lymphocyte infiltration increased in both groups (P = 0.0104). However, macrophage infiltration increased only in the AH Plus group (P = 0.0011). By the 14^th and 45^th days, lymphocyte and macrophage infiltrations were reduced. At the end of the experimental period, no statistically significant differences were found between the AH Plus group and the Obtuseal group (P > 0.05).

Conclusion:

After 45 days, Obtuseal yielded a satisfactory tissue reaction; it was biocompatible when tested in subcutaneous rat tissue. On the basis of the obtained results, it was concluded that Obtuseal root canal sealer caused a satisfactory tissue reaction as AH plus, because it was biocompatible when tested in the subcutaneous tissue of rats.

Evaluation of the physicochemical properties and push-out bond strength of MTA-based root canal cement

AIM

This study investigated the flowability, setting time, pH, calcium release and bond strength of a MTA-based cement (MTA Fillapex(®)) compared to AH Plus and Sealapex.

MATERIALS AND METHODS

For the flowability test, the ISO 6876:2001 specification was utilized and for the setting time test, the ASTM C266-03 specification was utilized. For the pH and calcium release measurements, 10 samples were prepared for each group and analyzed for several different periods. For the push-out test, dentin disks were distributed into three groups, according to the cement utilized and into three subgroups, according to the root third (n = 10). After obturation, the specimens underwent push-out testing. The data were compared statistically using a significance level of 5%.

RESULTS

The flowability of all materials was found to be similar (p > 0.05). The setting times were different among the groups tested (MTA Fillapex < Sealapex < AH Plus) (p < 0.05). At days 7 and 28, the MTA Fillapex presented the higher pH values (p < 0.05). At 24 hours and at 14 days, the calcium release of the MTA Fillapex was similar to that of Sealapex (p > 0.05). AH Plus presented the lowest pH and calcium release values (p < 0.05). In all root thirds, the adhesion to the dentin of the MTA Fillapex and Sealapex were significantly lower than that of AH Plus (p < 0.05).

CONCLUSION

MTA Fillapex and Sealapex presented several similar properties and both were found to be different than AH Plus.

CLINICAL SIGNIFICANCE

This study evaluated the physicochemical and mechanical properties of new MTA-based root canal cement, in order to use this scaler in root canal fillings. MTA Fillapex showed satisfactory properties for clinical use.

Epiphany root canal sealer prepared with resinous solvent is irritating to rat subcutaneous tissues

Objective: This study assessed the biocompatibility of the Epiphany endodontic sealer prepared with resinous solvent of Epiphany system (Thinning resin) in rat subcutaneous tissues. Study Design: Polyethylene tubes were filled with the sealer and 4 groups were established: GI, Epiphany prepared with 1 drop of resinous solvent (RS); GII, Epiphany prepared with 1 drop of RS and photoactivated; GIII, Epiphany associated with self-etch primer and prepared with 1 drop of RS; GIV, Epiphany associated with self-etch primer, prepared with 1 drop of RS and photoactivated. The filled tubes were implanted into 4 different regions of the dorsum of 20 adult male rats. Results: After 7, 14 and 21 days, all groups presented a moderate to severe chronic inflammation, necrosis and foreign-body giant cells. At 42 days, although the intensity of chronic inflammatory reaction decreased, the other features still were observed. Conclusion: The Epiphany sealer prepared with the RS was irritating to rat subcutaneous tissues.

Key words:Biocompatibility, Epiphany, methacrylate resin sealer, resinous solvent, root canal sealer.

An endodontic sealer induces a pathological condition when associated with persistent tissue toxicity and presence of myofibroblasts

The aims of this study were to evaluate the ratio between inflammatory reactions induced by four endodontic sealers and the occurrence of fibrosis and the number of myofibroblasts with positivity to α-smooth-actin muscle (α-SMA). Polyethylene tubes were filled with a root canal sealer (Endofill, AH Plus, Acroseal and Epiphany) and inserted into 4 site at the dorsal region of 24 Wistar rats; 2 empty tubes (control) were grafted in 6 rats. After 7, 21, and 45 days, 8 animals were euthanized, providing 6 specimens per test group and 2 specimens from the control group. The fragments were subjected to histological processing and immunohistochemical analysis for anti α-SMA protein. All specimens, except those from the control group, presented severe inflammatory reaction on the 7th postoperative day, which also coincided with a large number of myofibroblasts. On the 21st and 45th days post-surgery, the inflammatory reaction induced by Endofill, AH Plus and Acroseal decreased significantly, which coincided with reduced presence of myofibroblasts and usual collagen deposition. In contrast, in the group filled with Epiphany, significant inflammatory cell infiltrate was present in all analyzed periods. The persistence of an inflammatory reaction induced by endodontic sealer may also induce the development of fibrosis in combination with presence of myofibroblasts.

Biocompatibility of sealers used in apical surgery: a histological study in rat subcutaneous tissue

The aim of this study was to evaluate the biocompatibility of sealers used in apical surgery in rat subcutaneous tissue. Sterile polyethylene tubes were filled with the following sealers: Sealapex, Sealapex with addition of zinc oxide, Sealer 26, Sealer 26 with thicker consistency (greater powder-to-resin ratio) and White MTA. The tubes were implanted in the dorsum of male rats and after 7, 21 and 42 days, the animals were killed, obtaining 5 specimens for each sealer in each evaluation period. The lateral surface of the tube was used as negative control. The inflammatory reaction to contact with the sealers was classified as absent, mild, moderate and severe. At 7 days, all sealers caused similar inflammatory reactions in the connective tissue of the animals, with most specimens presenting a moderate to intense chronic inflammatory reaction, with presence of multinucleated giant cells. At 21 days, Sealer 26 and Sealer 26 with thicker consistency presented more intense inflammatory reaction (p=0.004), whereas after 42 days, the inflammatory reaction ranged from absent to mild with statistically similar results for both materials (p=0.08). Except for MTA, all sealers presented foreign-body granulomatous reaction at 42 days. All sealers but Sealapex presented a statistically significant decrease of the inflammatory reaction over time. In conclusion, all sealers caused moderate to severe inflammation in the earlier evaluation period. However, Sealer 26 and Sealer 26 with thicker consistency caused more intense inflammatory reactions after 21 days of contact with the tissues and no granulomatous reaction was observed for MTA at the final period of analysis.