Histological analysis of biocompatibility of different surgical adhesives in subcutaneous tissue

Analysis of Tissue Repair of a New Cement Based on Calcium and Strontium Aluminates: A Triple-Blinded, Randomized, Controlled Trial in an Animal Model

OBJECTIVE

 The focus of this triple-blind randomized study was to evaluate the biocompatibility of a new root canal filling sealer (RCFS) based on tristrontium aluminate and dodecacalcium hepta-aluminate in living tissue.

MATERIAL AND METHODS

 Forty-five Wistar rats (Rattus norvegicus) were divided into three groups: control (polyethylene), sealer (Bio-C Sealer, Londrina, PR, Brazil), and experimental (tristrontium aluminate and dodecacalcium hepta-aluminate). The tissues were analyzed under an optical microscope to assess different cellular events at different time intervals (7, 15, and 30 days).

STATISTICAL ANALYSIS

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

RESULTS

 In the initial period, a moderate inflammatory infiltrate was observed, similar between the endodontic cements groups (p = 0.725). The intensity of the infiltrate decreased with time, with no significant difference among the groups (p > 0.05). The number of young fibroblasts was elevated in all groups evaluated at 7 days. The experimental group showed the highest number of cells at all time intervals, but the difference with the sealer group at 7 (p = 0.001) and 15 days (p = 0.002) and the control group at 30 days was not significant (p = 0.001). Regarding tissue repair events, the amount of collagen fibers increased over the experimental intervals, with no significant difference between the sealer and control groups (p > 0.05).

CONCLUSION

 The experimental RCFS based on calcium and strontium aluminates proved to be biocompatible for use in close contact with periapical tissue, inducing a low inflammatory reaction and favoring rapid tissue repair.

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.

In vivo Hemostatic Activity of Jatropha mollissima: A Triple-Blinded, Randomized, Controlled Trial in an Animal Model

Objective The objective of this study was to evaluate the hemostatic activity of the sap from Jatropha mollissima (Pohl) Baill. in rats.

Materials and Methods Twenty-four Wistar rats were randomized into four groups ( n = 6): the JM25 and JM40 groups were treated with ethanolic extract from the sap of J. mollissima , in a concentration of 25 and 40 mg·mL ¹ , respectively; the MO group was treated with Monsel’s solution and the control group SC with a 0.9% sodium chloride solution.

Statistical Analysis Data were submitted to the Kurskal–Wallis’ test, followed by Dunn’s post hoc ( p < 0.05).

Results There was a significant reduction in the bleeding time of the group from the JM25 extract ( p = 0.001) when compared with MO and SC. There were no statistically significant differences between groups JM25 and JM40 ( p > 0.05). The JM25 group did not present rebleeding, a result significantly different from the MO group ( p = 0.001). Monsel’s solution showed significant bleeding, six times greater than the control group SC.

Conclusion The J. mollissima extract, in the concentration of 25 mg·mL ¹ , showed the highest hemostatic efficiency and was found to be a promising biomaterial for the elaboration of a hemostatic product.

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.

Effect of chitosan and Dysphania ambrosioides on the bone regeneration process: A randomized controlled trial in an animal model

The focus of this triple-blind study was on evaluating the effect of chitosan combined with Dysphania ambrosioides (A) extract on the bone repair process in vivo. In total, 60 male Wistar rats (Rattus norvegicus albinus) weighing between 260 and 270 g were randomly selected for this study and distributed into four groups (n = 15). Group C (chitosan), Group CA5 (chitosan + 5% of D. ambrosioides), Group CA20 (chitosan + 20% of D. ambrosioides), and Group CO (Control-Blood clot). In each animal, bone defects measuring 2 mm in diameter were performed in both tibias for placement of the substances. After 7, 15, and 30 days, the animals were sedated and sacrificed using the cervical dislocation technique and the tissues were analyzed under optical microscope relative to the following events: inflammatory infiltrate, necrosis, osteoclasts, osteoblasts, fibroblasts, periosteal, and endosteal bone formation. The data were evaluated to verify distribution using the Kolmogorov-Smirnov test, and variance, using the Levene test; as distribution was not normal, data were subjected to the Kruskal-Wallis and Dunn nonparametric tests (p < .05). A significant inflammatory infiltrate was observed in Group CA5 (p = .008) in the time interval of 7 days, and in Group C at 15 (p = .009) and 30 (p = .017) days. Osteoblastic activity was more significant in Group CA20 (p = .027) compared with CA5 in the time interval of 7 days. Group CA20 demonstrated a significantly higher endosteal and periosteal bone formation value in the time interval of 7 (p = .013), 15 (p = .004), and 30 days (p = .008) compared with the other groups. The null hypothesis was refuted, bone regeneration was faster in spheres with an association of chitosan and 20% extract, and complete bone repair occurred clinically at 15 days and histologically at 30 days. The spheres proved to be a promising method for the biostimulation of alveolar bone repair and bone fractures.

In Vivo Biocompatibility, Mechanical, and Antibacterial Properties of Cements Modified with Propolis in Different Concentrations

Objectives  The focus of this triple-blind randomized study was to evaluate the mechanical properties, antibacterial effect, and in vivo biocompatibility of glass ionomer cements (GICs) modified with ethanolic extracts of propolis (EEP).

Materials and Methods  For biocompatibility tests, 135 male Wistar rats were used and divided into nine groups: Group C (control, polyethylene), Groups M, M10, M25, M50 (Meron; conventional, and modified with 10%, 25%, 50% EEP, respectively), Groups KC, KC10, KC25, KC50 (Ketac Cem; conventional, and modified with 10%, 25%, 50% EEP, respectively). The tissues were analyzed under an optical microscope for different cellular events in different time intervals. Shear bond strength test (SBST) on cementation of metal matrices ( n = 10, per group), adhesive remnant index (ARI) in bovine incisors ( n = 10, per group), and antibacterial properties by the agar diffusion test ( n = 15, per group) were analyzed.

Statistical Analysis  Data were analyzed by Kruskal–Wallis test followed by Dunn, and one-way analysis of variance test followed by Tukey’s test ( p < 0.5).

Results  Morphological evaluation demonstrated intense inflammatory infiltrate in Groups M10 and KC10 in the time intervals of 7 ( p = 0.001) and 15 ( p = 0.006) days. Multinucleated giant cells were shown to be more present in Group M1, with statistical difference from Control and KC50 Groups in the time interval of 7 days ( p = 0.033). The SBST showed no statistical significance among the groups ( p > 0.05). Antibacterial property showed a statistically significant difference between Meron and Meron 50%-EEP Groups, and between Ketac and Ketac 50%-EPP Groups ( p = 0.001).

Conclusions  The intensity of histological changes resulting from the cements was shown to be inversely proportional to the concentration of propolis added; Ketac 50%-EPP was the concentration that had the most favorable biocompatibility results. Addition of EEP to GIC did not negatively change the SBST and ARI. Antibacterial property demonstrated a concentration-dependent effect.

Antimicrobial, mechanical and biocompatibility analysis of chlorhexidine digluconate-modified cements

Background

The focus of this study was to evaluate the antimicrobial, mechanical properties and biocompatibility of glass ionomer (GICs) modified by Chlorhexidine (CHX).

Material and Methods

For biocompatibility, 105 male Wistar rats were used, divided into 7 groups (n=15): Group C (Control,Polyethylene), Groups M, M10, M18, and Groups RL, RL10, RL18 (M-Meron and RL-Riva Luting: conventional, and modified with 10%, and 18% CHX, respectively). The tissues were analyzed under optical microscope for different cellular events and time intervals. Antibacterial effect and Shear Bond Strength Test (SBST) were also analyzed. Biocompatibility was analyzed by the Kruskal-Wallis and Dunn tests; SBST one-way ANOVA and Tukey test (P<0.05). For the antibacterial effect, the Kruskal-Wallis and Friedman, followed by Dunn (P<0.05) tests were used.

Results

Morphological study of the tissues showed inflammatory infiltrate with significant differences between Groups C and RL18, in the time intervals of 7(P=0.013) and 15(P=0.032) days. The antimicrobial effects of the cements was shown to be CHX concentration-dependent (P=0.001). The SBST showed no significant difference between the Groups of Meron cement (P=0.385), however, there was difference between Group RL and Groups RL10 and RL18 (P=0.001).

Conclusions

The addition of CHX did not negatively influence the SBST. Meron-CHX-10% was the most biocompatible, and Riva-CHX-18% had more influence on the inflammatory process and presented slower tissue repair.

Key words:Glass ionomer, chlorhexidine, biocompatibility, antimicrobial properties, microscope.