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

Influence of chlorhexidine digluconate on biocompatibility of cements: Morphological and immunohistochemistry analysis

In this study, the in vivo biocompatibility was evaluated by using conventional ionomer cements modified with Chlorhexidine (CHX) in different time intervals. In total, 105 male Wistar rats were randomized into seven groups: control, groups M, M10, M18 and groups RL, RL10, RL18 (M-Meron and RL-RivaLuting, and added CHX-10% and CHX-18%, respectively). Histological analyses of inflammatory infiltrate and collagen fibers, and immunohistochemistry of CD68+ for macrophages (MOs) and multinucleated giant cells (MGCs) were performed. Data were analyzed using the Kruskal-Wallis and Dunn (p < .05) tests. Intense inflammatory infiltrate was demonstrated in Group Riva CHX-18% within 7 and 15 days (p < .05), without differences after 30 days. For collagenization, healing of the groups was compatible with that of control in 15 and 30 days (p > .05). Immunomarking of CD68+ was more significant in the groups with higher concentration of CHX. There was significant difference in quantity of MGCs in groups with 18% CHX, Meron (p = .001) in 7 days, and in Riva at 30 days (p = .001). Significant difference was also found in quantities of MOs in Groups Meron and Riva in 7 days (p = .001), and only in Riva at 15 and 30 days (p = .001). The cements with addition of CHX demonstrated biocompatibility with tissues. Riva CHX-18% had the most effect on cells of the inflammatory process but showed satisfactory tissue repair.

Effect of Yellow Propolis on Biocompatibility of Cements: Morphological and Immunohistochemistry Analysis

Objective  The focus of this study was to evaluate the biocompatibility of ionomer cements modified with ethanolic extracts of propolis (EEP) in different concentrations and time intervals.

Materials and Methods  In total, one hundred and thirty-five male Wistar rats were randomized into nine groups: Control, Groups Meron, and Groups Ketac (conventional, and added with 10, 25, 50% EEP, respectively). Histological analyses of inflammatory infiltrate and collagen fibers, and immunohistochemistry of CD68+ for macrophages (MOs) and multinucleated giant cells (MGCs) were performed.

Statistical Analysis  Data were analyzed using the Kruskal—Wallis and Dunn ( p < 0.05) tests.

Results  Intense inflammatory infiltrate was demonstrated in the cements with 10% EEP at 7 days and 15 days ( p < 0.05), only Group Ketac 10% EEP ( p = 0.01) at 30 days. A smaller quantity of collagen fibers was observed in the cements with 10% EEP ( p = 0.01) at 7 days, and Group Meron 10% EEP ( p = 0.04) at 15 days. MOs and MGCs showed significant difference for the cements with 10% EEP ( p = 0.01) at 7 and 15 days. At 30 days, MOs persisted in the Groups with 10% EEP.

Conclusions  The concentration of 10% EEP had the greatest influence on the inflammatory and tissue repair processes. The concentrations of 25 and 50% EEP demonstrated biocompatibility similar to that of cements that did not receive EEP.

Semiautomated quantification of the fibrous tissue response to complex three-dimensional filamentous scaffolds using digital image analysis

Fibrosis represents a relevant response to the implantation of biomaterials, which occurs not only at the tissue-material interface (fibrotic encapsulation) but also within the void fraction of complex three-dimensional (3D) biomaterial constructions (fibrotic ingrowth). Usual evaluation of the biocompatibility mostly depicts fibrosis at the interface of the biomaterial using semiquantitative scores. Here, the relations between encapsulation and infiltrating fibrotic growth are poorly represented. Virtual pathology and digital image analysis provide new strategies to assess fibrosis in a more differentiated way. In this study, we adopted a method previously used to quantify fibrosis in visceral organs to the quantification of fibrosis to 3D biomaterials. In a proof-of-concept study, we transferred the "Collagen Proportionate Area" (CPA) analysis from hepatology to the field of biomaterials. As one task of an experimental animal study, we used CPA analysis to quantify the fibrotic ingrowth into a filamentous scaffold after subcutaneous implantation. We were able to demonstrate that the application of the CPA analysis is well suited as an additional fibrosis evaluation strategy for new biomaterial constructions. The CPA method can contribute to a better understanding of the fibrotic interactions between 3D scaffolds and the host tissue responses.

Tissue response to white mineral aggregate-based cement containing barium sulfate as alternative radiopacifier: A randomized controlled animal study

The purpose of this study was to investigate the tissue reaction stimulated by BaSO4 - and Bi2 O3 -containing White MTA Angelus, in comparison with Bi2 O3 -containing white Portland cement, and white ProRoot MTA. Thirty-six adult male Wistar rats (Rattus norvegicus), weighing between 250 and 300 g, were distributed into three groups (n = 12) in accordance with the period of sacrifice (15, 30, and 60 days). Four polyethylene tubes filled with the tested cements were implanted into the dorsum of each rat. Lateral wall of the tubes served as the negative control. After the experimental periods, the animals were euthanized by overdose of pentobarbital anesthetic solution, and the specimens were prepared for microscopic analysis under ×50, ×100, and ×400 magnifications. Inflammatory scores (0-3) were used to grade the tissue reaction. Data were analyzed by the Kruskal-Wallis test and Dunn's test for individual comparisons (p < .05). A mild to moderate inflammatory tissue reaction was observed at the 15-day period, which decreased over the course of the periods for all cements, except for Portland cement. There was no significant difference among the tissue responses for ProRoot MTA, BaSO4 - and Bi2 O3 -containing White MTA Angelus at the 60-day period (p > .05). The Portland group had moderate inflammatory reaction at the final period of analysis, which was statistically different when compared to the other groups (p < .05). The microscopic findings of this animal study suggest that the addition of BaSO4 to White MTA Angelus does not hampers the biocompatibility of the cement.

Effect of the plant-based hemostatic agent Ankaferd Blood Stopper® on the biocompatibility of mineral trioxide aggregate

Background

Due to the detrimental effect of blood contamination on the physico-chemical properties of mineral trioxide aggregate (MTA), obtaining an effective hemostasis in the surgical crypt during apical surgery is of paramount importance. The purpose of this in vivo study was to analyze the effect of Ankaferd Blood Stopper® (ABS) contamination on the biocompatibility of MTA.

Methods

Forty of 56 Wistar–Albino rats were divided randomly and equally into two groups (MTA and MTA-ABS) according to whether or not a hemostatic agent was used. The remaining 16 rats were designated as the control group. Rats in the experimental groups received freshly mixed MTA-Angelus in polyethylene tubes, which were inserted into monocortical bore holes created in their tibias. In the MTA-ABS group only, 0.5 mL of ABS solution was administered topically on the defect sites followed by implantation of MTA tubes. Inflammation, foreign-body reaction (FBR), necrosis, fibrosis, and new bone formation (NBF) were studied 7, 30, 60, and 90 days after implantation.

Results

On day7, statistically significant differences were found in tissue reactions with regard to NBF and necrosis (p = 0.044 and p = 0.024, respectively), the latter being observed in 40 % of the samples only in the MTA-ABS group. Slight inflammation in all groups was confined to day-7 only. Mild necrosis was present in the MTA-ABS group only on day-7. Severity of the foreign body reaction and fibrosis was limited. New bone formation increased gradually over time in all groups, reaching a maximum on day-90.

Conclusions

MTA and ABS-contaminated MTA are equally biocompatible. ABS does not impair the properties of MTA.

Electronic supplementary material

The online version of this article (doi:10.1186/s12903-016-0302-0) contains supplementary material, which is available to authorized users.

The biocompatibility of a new endodontic paste used in dental trauma

<title>Abstract</title><sec><title>Objective</title><p>This study investigated the short-term subcutaneous tissue reaction of a new endodontic paste, based on the association among calcium hydroxide [Ca(OH)₂], 2% chlorhexidine gel (CHX) and zinc oxide (ZnO) in comparison with a control paste, and the individual substances alone.</p></sec><sec><title>Material and method</title><p>Twenty-four male wistar rats were used. Polyethylene tubes containing the materials were implanted into the dorsal connective tissue of rats. Empty implanted tubes served as controls. The materials used were: Ca(OH)₂+CHX+ZnO paste in two different proportions (2:1:2) and (2:1:3), a control paste, Ca(OH)₂+CHX (2:1), and the substances alone. After time intervals of 2, 3, 7 and 15 days, the animals were euthanized and the specimens prepared for histological processing. Data were evaluated qualitatively according to the levels of tissue repair and the degree of inflammation.</p></sec><sec><title>Result</title><p>On the second day all the materials were observed to cause a severe inflammatory response. On the third day, the pastes Ca(OH)₂+CHX+ZnO (2:1:2) and (2:1:3) showed reduction in degree of inflammation. On seventh day the tissue was already more organized with presence of collagen fibers in all materials. After 15 days it was found that compound Ca(OH)₂+CHX+ZnO (2:1:2) showed areas with no inflammatory infiltrate.</p></sec><sec><title>Conclusion</title><p>The experimental pastes, Ca(OH)₂+CHX+ZnO in two different proportions (2:1:2) and (2:1:3), showed favorable results with respect to biocompatibility, when evaluated for a short-term.</p></sec>

The Influence of Root-End Filling Materials on Bone Healing - An Experimental Study

AIMS

The aim of this experimental study is to assess the bone healing phenomenon produced in the presence of several dental materials: a polycarboxylate cement, a glass-ionomer cement, a composite resin and MTA (mineral trioxide aggregate) based cement.

METHODS

The biocompatibility of four root-end fillings materials, used in periapical surgery was investigated after intra-osseous implantation of the materials in rats' calvaria. Tissue reaction was studied at 2, 4, 6, 8, 10 and 12 weeks after implantation. We took into consideration the presence of inflammatory cells (polymorphonuclear leukocytes, macrophages, plasma cells, lymphocytes and giant cells) and classified the aspects of the histological samples according to the following scale: 0 - no inflammation, 1 - mild, isolated inflammation, 2 - moderate, localized inflammatory reaction, 3 - severe, diffuse and intense inflammatory reaction.

RESULTS

The inflammatory reaction was present at the six intervals for all the tested materials, but at 12 week interval, the reaction was minimal in all cases. Also, a dissolution reaction was observed for all the materials, less intense for glass-ionomer cement and polycarboxilate cement.

CONCLUSIONS

At the end of the experimental period, glass-ionomer cement and polycarboxilate cement suffered a lesser dissolution reaction as compared to the second group of tested materials.

Biocompatibility and setting time of CPM-MTA and white Portland cement clinker with or without calcium sulfate

Objective:

To evaluate the biocompatibility and the setting time of Portland cement clinker with or without 2% or 5% calcium sulfate and MTA-CPM.

Material and Methods:

Twenty-four mice (Rattus norvegicus) received subcutaneously polyethylene tubes filled with Portland cement clinker with or without 2% or 5% calcium sulfate and MTA. After 15, 30 and 60 days of implantation, the animals were killed and specimens were prepared for microscopic analysis. For evaluation of the setting time, each material was analyzed using Gilmore needles weighing 113.5 g and 456.5 g, according to the ASTM specification Number C266-08 guideline. Data were analyzed by ANOVA and Tukey's test for setting time and Kruskal-Wallis and Dunn test for biocompatibility at 5% significance level.

Results:

Histologic observation showed no statistically significant difference of biocompatibility (p>0.05) among the materials in the subcutaneous tissues. For the setting time, clinker without calcium sulfate showed the shortest initial and final setting times (6.18 s/21.48 s), followed by clinker with 2% calcium sulfate (9.22 s/25.33 s), clinker with 5% calcium sulfate (10.06 s/42.46 s) and MTA (15.01 s/42.46 s).

Conclusions:

All the tested materials showed biocompatibility and the calcium sulfate absence shortened the initial and final setting times of the white Portland cement clinker.

In Vitro Cytotoxicity of White MTA, MTA Fillapex® and Portland Cement on Human Periodontal Ligament Fibroblasts

The aim of this study was to compare the in vitro cytotoxicity of white mineral trioxide aggregate (MTA), MTA Fillapex® and Portland cement (PC) on human cultured periodontal ligament fibroblasts. Periodontal ligament fibroblast culture was established and the cells were used for cytotoxic tests after the fourth passage. Cell density was set at 1.25 X10 4 cells/well in 96-well plates. Endodontic material extracts were prepared by placing sealer/cement specimens (5X3mm) in 1mL of culture medium for 72 h. The extracts were then serially two-fold diluted and inserted into the cell-seeded wells for 24, 48 and 72 h. MTT assay was employed for analysis of cell viability. Cell supernatants were tested for nitric oxide using the Griess reagent system. MTA presented cytotoxic effect in undiluted extracts at 24 and 72 h. MTA Fillapex® presented the highest cytotoxic levels with important cell viability reduction for pure extracts and at ½ and ¼ dilutions. In this study, PC did not induce alterations in fibroblast viability. Nitric oxide was detected in extract-treated cell supernatants and also in the extracts only, suggesting presence of nitrite in the soluble content of the tested materials. In the present study, MTA Fillapex displayed the highest cytotoxic effect on periodontal ligament fibroblasts followed by white MTA and PC.

Sealing Ability of MTA Used as a Root End Filling Material: Effect of the Sonic and Ultrasonic Condensation

Despite the excellent properties of mineral trioxide aggregate (MTA), the condensation technique may have some influence in its sealing ability. The purpose of this study was to compare the sealing ability of sonic and ultrasonic setting of MTA. Thirty-four extracted human teeth had their canals prepared and filled with Sealapex sealer and gutta-percha using the active lateral condensation technique. The teeth were rendered waterproof and apicoectomy performed at 3 mm from the apex. Root-end cavities (3.0 mm deep and 1.4 mm diameter) were prepared with diamond ultrasonic tips. The root-end cavities were filled with Pro-Root MTA® with ultrasonic vibration, sonic vibration or no vibration. The positive control group did not receive any material while the negative control group was totally rendered waterproof. After material set, the specimens were immersed in Rodhamine B for 24 h, under vacuum in the first 15 min, then washed, dried and split longitudinally for evaluating the infiltration at the dentin/material interface. Data were analyzed using ANOVA and Tukey's tests at 5% significance level. Sonic vibration promoted the lowest infiltration values (p<0.05). It was concluded that sonic vibration could be considered an efficient aid to improve the sealing ability of MTA when used as root-end filling material.

In vitro genotoxicity and cytotoxicity in murine fibroblasts exposed to EDTA, NaOCl, MTAD and citric acid

The aim of the present study was to evaluate the capacity of some root canal irrigants to induce genetic damage and/or cellular death in vitro. Murine fibroblast cells were exposed to ethylenediaminetetraacetic acid (EDTA), sodium hypochlorite (NaOCl), MTAD™ and citric acid in increasing concentrations for 3 h at 37ºC. The negative control group was treated with vehicle control (phosphate buffer solution - PBS) for 3 h at 37°C, and the positive control group was treated with methylmetanesulfonate, 1 μM. for 3 h at 37°C. Cytotoxicity was assessed by the trypan blue test and genotoxicity was evaluated by the single cell gel (comet) assay. The results showed that exposure to 2.5% and 5% NaOCl and 8.5% citric acid resulted in a significant cytotoxic effect. NaOCl, EDTA and citric acid did not produce genotoxic effects with respect to the comet assay data for all evaluated concentrations. Although MTAD was not a cytotoxic agent, it showed significant genotoxic effects at all tested concentrations (ANOVA and Tukey's test; p<0.05). NaOCl, EDTA and citric acid were found to be cytotoxic in a dose-dependent manner, but they were not genotoxic. MTAD did not cause cell death, but presented genotoxic effects.