Influence of zinc oxide and eugenol sealer on concentration of zinc, calcium and copper in rat tissues

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.

Comparision of biocompatibility and cytotoxicity of two new root canal sealers

The aim of this study was to investigate the remote organ toxicity and connective tissue reaction of two new root canal sealers ("GuttaFlow(®)" and "EndoREZ(®)") and to compare them with zinc oxide eugenol sealer using biochemical and histopathological parameters. A total of 60 white albino Wistar rats were used in the study. 0.1ml of GuttaFlow(®), EndoREZ(®) or Kerr Pulp Canal Sealer(®) were administered subcutaneously into the mid-dorsal thoracic region of rats (15 in each group). Control rats were given saline only. Rats were decapitated after 24h, on day 7 and on day 30 of the experiment and tissue samples from lung, liver, kidney and skin were removed for the determination of malondialdehyde (MDA) and glutathione (GSH) levels. In parallel, tissues were also examined histologically. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) levels, and creatinine and blood urea nitrogen (BUN), concentrations (BUN) were measured to assess liver and kidney functions, respectively. Tumor necrosis factor (TNF) and lactate dehydrogenase (LDH) were also assayed in serum samples. No statistical differences were found among the control and EndoREZ(®), GuttaFlow(®) and Kerr Pulp Canal sealers regarding tissue MDA, GSH levels or serum parameters (p>0.05) at all time points examined. Both of the new root canal sealers showed good compatibility and acceptable tissue toxicity.

In vitro genotoxicity of root canal sealers

AIM

To evaluate the effect of leakage on differences in genotoxicity of root canal sealers ex vivo according to their main components using two different cytogenetic assays.

METHODOLOGY

Six materials of different composition (GuttaFlow, Epiphany, Diaket, IRM, SuperEBA and Hermetic) were tested on human peripheral blood lymphocytes using the comet assay and chromosomal aberration analysis. Prepared materials were eluted in physiological solution for 1 h, 1 day, 5 and 30 days. Thereafter cultures were treated with 8 microg, 4 microg and 2 microg of each sealer. Frequencies of chromatide and chromosome breaks and accentric fragments were determined. Comet assay was used to evaluate primary DNA damage by measuring tail length and tail intensity. Chi-square, Fisher's PLSD (Protected Least Significant Difference) and Kruskall-Wallis non parametric tests were used for statistical analysis.

RESULTS

After 1-h elution only the highest dose of Diaket, Hermetic and SuperEBA significantly (P = 0.035, P = 0.048, P = 0.037 respectively) affected the measured cytogenetic parameters. The migration ability of DNA was more strongly affected than induction of chromosomal aberrations. After elutions longer than 24 h none of the tested sealers exhibited a genotoxic effect.

CONCLUSION

Under the conditions used in the study all sealers had acceptable biocompatibility in terms of genotoxicity.

A new silicon-based root canal sealer (Roekoseal-Automix)

This study evaluated the new silicon-based sealer 'Roekoseal-Automix' (RSA) with respect to sealing, bonding capabilities and biocompatibility with rat subcutaneous connective tissue. For the microleakage study, 36 single rooted teeth were instrumented and 30 of these obturated with either Grossman's sealer or RSA using lateral condensation technique (15 of each). Six teeth were not obturated and used as control group. For investigating bonding capability, 10 of the obturated roots with RSA and Grossman's sealer were ground and split longitudinally and examined by scanning electron microscopy (SEM). The RSA was found to seal significantly better than Grossman's sealer. The SEM examination revealed a good bond between RSA and the dentine and between RSA and the gutta-percha. Tissue reaction was evaluated by injecting 0.1 mL RSA into the connective tissue of 21 male Albino-Wistar rats and observing at 24 h, 7 days and 30 days and 30 days. Formation of a new granulation tissue with fibrous tissue adjacent to the material at 30 days. This study found that RSA performed well.

Biocompatibility of dental materials used in contemporary endodontic therapy: a review. Part 2. Root-canal-filling materials

Root-canal-filling materials are either placed directly onto vital periapical tissues or may leach through dentine. The tissue response to these materials therefore becomes important and may influence the outcome of endodontic treatment. This paper is a review of the biocompatibility of contemporary orthograde and retrograde root-canal-filling materials.

Influence of inositolhexaphosphori acid (phytic acid) on the copper distribution in tissues and the excretion of copper in rats

The aim of the present study was to investigate the effect of the administration of phytic acid on copper (Cu) concentrations in several different rat tissues. The animals used were divided into three groups: Group A (received a diet supplemented with 2% phytic acid), group B (received a diet supplemented with 10% phytic acid) and group C (control). At the end of the experiment, the animals were sacrificed and the concentration of copper was determined in the different tissues. Phytic acid significantly increased Cu concentration in the duodenum of the animals of both groups as well as in the lungs and blood of the animals of group A. The copper concentration was also increased in the uterus and bone of the animals of group B. On the other hand, the stomach copper concentration of the animals of both groups, the heart and lung copper concentrations of the animals of group B as well as the jejunum, colon and hair copper concentrations of the animals of group A were significantly decreased. Copper excretion through feces was significantly decreased in the animals of both groups, while the excretion through urine was not significantly affected by the administration of phytic acid. In conclusion, the administration of phytic acid can produce translocation and/or elimination of copper in various tissues of rats.

Biocompatibility of root canal filling materials

Results of in vitro and in vivo studies clearly indicate that some endodontic sealers may cause local and systemic adverse effects. Though occasionally contradictory data has been reported from various authors, it may be concluded that zinc-oxide-eugenol sealers possess a marked cytotoxic and tissue-irritating potency. Most Ca(OH)2-based materials, however, were biocompatible. Genotoxic effects have been observed with sealers releasing paraformaldehyde or containing mutagenic substances, such as bisphenol-A-diglycidyl-ether or its derivatives. It cannot be excluded that these materials may pose a systemic risk because formaldehyde is rapidly distributed systemically following its application into the pulp cavity. Furthermore an increasing number of cases with an aspergillosis of the maxillary sinus have been observed which were mainly caused by zinc-releasing endodontic sealers. Overall, it is recommended that for endodontic practice, sealers that have been found to be biocompatible in a "mixed bag" of various in vitro and in vivo tests, be selected. From this point of view, ZnOE-sealers should no longer be used for root canal fillings. This recommendation applies also to sealers containing paraformaldehyde or generating this substance during their setting reaction. More experimental and clinical studies are necessary to elucidate whether new materials, such as mineral trioxide aggregate (MTA) or calcium phosphate cement, will be biocompatible alternatives in the future.