Systemic effect of mineral aggregate-based cements: histopathological analysis in rats

Systemic effect of calcium silicate-based cements with different radiopacifiers-histopathological analysis in rats

Aim

This in vivo study aimed to examine the systemic effects of contemporary calcium silicate cements (CSC) contain different radiopacifiers in rats.

Materials & Methods

Polyethylene tubes filled with BIOfactor MTA (BIO), Neo MTA Plus (NEO), MTA Repair HP (REP), Biodentine (DENT) and empty tubes (control group) were implanted into the subcutaneous tissues of 80 male Spraque Dawley rats for 7 and 30 days (n = 8). After 7 and 30 day, samples of liver and kidney tissues were submitted to histopathological analysis. Blood samples were collected to evaluate changes in hepatic and renal functions of rats. Wilcoxon and post hoc Dunn Bonferroni tests were used to compare between the 7th and 30th days in order to evaluate the histopathological data. Paired-sample t-test was used to compare laboratory values between the 7th and 30th days, ANOVA analysis and a post hoc Tukey test were used to compare values between groups (p < 0.05).

Results

On the 7th day, REP, BIO and NEO groups were statistically similar in kidney tissue and the degree of inflammation was found to be significantly higher in these groups compared to the control and DENT groups. On the 30th day, the degree of inflammation of the REP and NEO groups in the kidney tissue was found to be significantly higher than the control, BIO and DENT groups. Although the inflammation in the liver was moderate and mild on the 7th and 30th days, no statistically significant difference was observed between the groups. Vascular congestion was evaluated as mild and moderate in kidney and liver in all groups, and no statistically significant difference was observed between the groups. While there was no statistically significant difference between the groups in the 7th day AST, ALT and urea values, when the creatinine values were compared, the DENT and NEO groups were found to be statistically similar and significantly lower than the control group. On the 30th day, ALT values were statistically similar between the groups. The AST values of the BIO group were found to be significantly higher than the DENT group. While BIO, DENT, NEO and control groups had statistically similar urea values, the REP group was found to be significantly higher than the other groups. The creatinine value of the REP group was significantly higher than the groups other than the control group (p < 0.05).

Conclusion

CSCs with different radiopacifiers had similar and acceptable effects on the histological examination of the kidneys and liver systemically, and serum ALT, AST, urea, creatinine levels.

Can strontium replace calcium in bioactive materials for dental applications?

The substitution of calcium with strontium in bioactive materials has been promising but there has been some concern over the material instability and possible toxicity. The aim of this research was the synthesis and characterization of calcium and strontium substituted bioactive materials and assessment of interactions with local tissues and peripheral elemental migration in an animal model. A bioactive glass, hydroxyapatite and hydraulic calcium silicate with 50% or 100% calcium substitution with strontium were developed and the set materials were characterized immediately after setting and after 30 and 180-days in solution. Following subcutaneous implantation, the local (tissue histology, elemental migration) and systemic effects (elemental deposition after organ digestion) were assessed. The strontium-replaced silicate cements resulted in the synthesis of partially substituted phases and strontium leaching at all-time points. The strontium silicate implanted in the animal model could not be retrieved in over half of the specimens showing the high rate of material digestion. Tissue histology showed that all materials caused inflammation after 30 days of implantation however this subsided and angiogenesis occurred after 180 days. Strontium was not detected in the local tissues or the peripheral organs while all calcium containing materials caused calcium deposition in the kidneys. The tricalcium silicate caused elemental migration of calcium and silicon in the local tissues shown by the elemental mapping but no deposition of calcium was identified in the peripheral organs verified by the assessment of the digested tissues. Strontium can substitute calcium in bioactive materials without adverse local or systemic effects.

Tracing the toxic ions of an endodontic tricalcium silicate-based sealer in local tissues and body organs

BACKGROUND

This study aimed to track the toxic ions released by MTA Fillapex, BioRoot RCS, and an experimental tricalcium silicate-based sealer (CEO) into local and distant tissues as well as to investigate their potential adverse effects. In addition, the chemical constituents of the sealers were also evaluated. The main components of the dry powders, pastes, and mixed sealers were characterized.

MATERIAL AND METHODS

Dry powder and sealer discs were each set for 72 h and their main components were characterized by energy dispersive X-ray spectroscopy. Polyethylene tubes filled with sealers were used to measure silicon and calcium ions. Polyethylene tubes filled with sealers or empty tubes were implanted into the dorsal connective tissue of Wistar rats. On days 7, 15, 30, and 45, the animals were euthanized and their brains, livers, kidneys, and subcutaneous tissues were removed and processed to determine the concentrations of chromium, cobalt, copper, lead, iron, magnesium and nickel using an inductively coupled plasma optical emission spectrometer.

RESULTS

The main compounds in all sealers were carbon, oxygen, silicon, and calcium. MTA Fillapex release more Si while highest levels of Si were found in presence of BioRoot. The release of Si and Ca ions promoted by MTA Fillapex raise by time. No traces of cobalt, chromium, or magnesium were detected in any tissue. Irrespective of the sealer, no traces of copper and lead were found in the subcutaneous tissue; however, they were observed in the organs. The highest concentration of iron was identified in the liver. All sealers exhibited similar nickel traces in the brain, kidney, and liver except for MTA Fillapex, which demonstrated levels higher than CEO in the subcutaneous tissue on day 7. Tracing nickel ions over time revealed that lowest concentrations were found in subcutaneous tissue.

CONCLUSION

Taken together, our data demonstrate that CEOs have chemical compositions similar to those of other commercial sealers. Furthermore, none of them exhibited a threat to systemic health. Moreover, the minimal amounts of iron and nickel detected were not related to the sealers.

Are resin-containing pulp capping materials as reliable as traditional ones in terms of local and systemic biological effects?

The aim of this study was to compare the local and systemic effects of current pulp capping materials containing resin with those of traditional materials in an animal study. A total of 48 rats were used: a control group (n=12) (sub-control and negative control), a resin-containing group (n=18) (Calcimol LC, Theracal LC, Activa-BioActive Base/Liner), and a traditional group (n=18) (Biodentine, ProRoot MTA, Dycal). The materials which had been placed in polyethylene tubes were implanted in subcutaneous pockets. The rats were sacrificed at 1, 2, or 4 weeks. Evaluations were made of subcutaneous connective tissue, the left kidney, liver, and blood samples. Of all the study groups, MTA demonstrated biocompatibility at a level close to that of the control groups. Inflammation was observed to be more severe in resin-containing materials, but Activa Base/Liner showed a more successful local and systemic tissue response.

Comparison of Bio-C Pulpo and MTA Repair HP with White MTA: effect on liver parameters and evaluation of biocompatibility and bioactivity in rats

AIM

To evaluate the tissue response promoted by Bio-C Pulpo (Bio), MTA Repair HP (MTA-HP) and White MTA (WMTA) and whether these materials cause liver changes in a rat experimental model.

METHODOLOGY

Polyethylene tubes filled with Bio, MTA-HP and WMTA, and empty tubes (control group, CG) were implanted into the subcutaneous tissues of rats for 7, 15, 30 and 60 days. Inflammatory reaction score (IRS), capsule thickness, number of inflammatory cells (IC), von Kossa reaction, interleukin-6 (IL-6) and alkaline phosphatase (ALP) immunohistochemistry reactions were performed. Combined methods, von Kossa followed by immunohistochemistry for detection of ALP, were performed. At 60 days, the serum glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) levels were measured and liver fragments were collected for histological analysis; the data were assessed by one-way ANOVA analysis followed by Sidak's post-test. The biocompatibility and bioactivity data were subjected to the two-way ANOVA analysis followed by Tukey post hoc test, except the IRS. The IRS data were subjected to the Kruskal-Wallis ANOVA non-parametric test followed by Dunn's test (p ≤ .05).

RESULTS

No significant difference was detected in serum GOT and GPT concentrations and in the number of hepatocytes among the experimental and CG samples. Although Bio-C Pulpo had the highest IC and IL-6-immunolabelled cells (p < 0.0001) at all periods, no significant difference was observed in the IRS among the materials, except at 60 days. In this period, the WMTA had lower IRS. All groups had a significant reduction in the capsule thickness and in the number of IC and IL-6-immunolabelled cells over time. Bio-C Pulpo, MTA-HP and WMTA specimens had greater immunoexpression of ALP than CG (p < .0001). At all periods, von Kossa-positive and birefringent structures were observed in the capsules around the materials. ALP-immunolabelled cells were also seen near von Kossa-positive structures.

CONCLUSIONS

Bio-C Pulpo, MTA-HP and WMTA materials did not cause morphological changes in the liver and no significant alteration in the serum GOT and GPT levels. Moreover, these bioceramic materials were biocompatible and exhibited bioactive potential. However, Bio-C Pulpo induced greater inflammatory infiltrate than MTA-HP and WMTA at all periods.

Evolution of endodontic medicine: a critical narrative review of the interrelationship between endodontics and systemic pathological conditions

Endodontics has gained emphasis in the scientific community in recent years due to the increase in clinical and in animal models studies focused on endodontic medicine, which aims to evaluate the interrelationship between systemic and periapical tissues pathological conditions. These studies have shown that systemic changes can boost the pathogenesis of endodontic infection, favoring its development and progression. A contrary relationship is reported in numerous studies that affirm the potential of endodontic infection to trigger systemic damage and may lead to the worsening of pre-existing pathologies. Recently, the potential of filling materials to develop systemic changes such as neurological alterations had been evaluated, also showing that systemic diseases can negatively influence tissue responses to filling materials after endodontic treatment. Despite advances in endodontic medicine studies, there are still gaps in knowledge on the mechanisms of interactions between apical periodontitis (AP) and systemic diseases and much research to be done. In this sense, this critical narrative literature review aimed to show the evolution of studies in endodontic medicine to help the endodontist to know the role of systemic diseases in the pathogenesis of AP and the possible interference in the repair of periapical tissues after endodontic treatment, as well as to evidence the systemic complications that can be triggered or aggravated in the presence of endodontic infection.

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.