Bismuth release from endodontic materials: in vivo analysis using Wistar rats

Abstract

Calcium silicate-based materials are used to block the communication between the root canal and the periodontal ligament space. This brings the materials into contact with tissues and the potential for local and systemic elemental release and movement. The aim of the study was to evaluate the elemental release of bismuth from ProRoot MTA in contact with connective tissues after 30 and 180 days as well as any accumulation in peripheral organs using an animal model. Tricalcium silicate and hydroxyapatite containing 20% bismuth oxide (HAp-Bi) were used as controls. The null hypothesis was that bismuth migrates from tricalcium silicate-based materials when associated with silicon. The materials were examined using scanning electron microscopy, energy dispersive spectroscopy (SEM/EDS) and X-ray diffraction prior to implantation as well as using SEM/EDS, micro X-ray fluorescence and Raman spectroscopy after implantation to assess elemental presence in surrounding tissues. Histological analysis was used to evaluate the changes in tissue architecture and inductively coupled plasma mass spectrometry (ICP-MS) was used to investigate the elemental deposition. For the systemic investigation, routine blood analysis was performed and organs were obtained to evaluate the presence of bismuth and silicon using ICP-MS after acid digestion. In the histological analysis of the implantation sites, macrophages and multinucleated giant cells could be observed after 30 days which after 180 days became a chronic infiltrate; although, no major differences were identified in red and white blood cell analyses and biochemical tests. Implantation altered the materials as observed in the Raman analysis and bismuth was detected both locally and within kidney samples after both periods of analysis, indicating the potential for accumulation of bismuth in this organ. Smaller amounts of bismuth than observed in the kidney were also detected in blood, liver and brain for the ProRoot MTA and HAp-Bi after 180 days. Bismuth was released from the ProRoot MTA locally and was detected systemically and in samples without silicon; thus, the null hypothesis was rejected. The bismuth release demonstrated that this element accumulated both locally and systemically, mainly in the kidneys in comparison with brain and liver regardless of the material base.

The efficacy of premixed bioceramic sealers versus standard sealers on root canal treatment outcome, extrusion rate and post‐obturation pain: A systematic review and meta‐analysis

“…Zirconium dioxide, Bismuth oxide or Tantalum pentoxide) and their release from periapical extrusion into the body fluids must be considered in future research. Recent ex vivo studies showed that, upon dissolution of CaSi sealers samples, the radiopacifiers could be spread in the surgical area, taken up by cells and transferred to other organs for their elimination by metabolic processes (de Azevedo Queiroz et al., 2021; Marciano et al., 2023).…”

Leaching and cytotoxicity of bismuth oxide in ProRoot MTA – A laboratory investigation

“…Furthermore, the presence of bismuth in previous cell culture studies induced an upregulation of metallothionein (a cysteine-rich protein involved in metal detoxification) expression (Cowan et al, 1996;Durnam and Palmiter, 1987;Kagimoto et al, 1991;Kaji et al, 1996), as bismuth compounds strong agonists for metallothionein. The research that has been undertaken aims to guide the dental clinician to select a bismuth-free calcium silicatebased material since bismuth oxide causes dentine discolouration, can migrate from the material to connective subcutaneous tissue (Schembri Wismayer et al, 2016) and bone (Marciano et al, 2023) and it can accumulate in peripheral organs (mainly kidneys) following implantation (Marciano et al, 2023).…”

Growth Factors Released from Advanced Platelet-Rich Fibrin in the Presence of Calcium-Based Silicate Materials and Their Impact on the Viability and Migration of Stem Cells of Apical Papilla

“…This is in contrast to bismuth oxide, the radioopacifier in MTA. Previous studies have shown the long-term release of bismuth oxide into the neighboring tissues and its interaction with other substances, which could potentially explain its influence on the release of growth factors in conditioned media [ 45 , 46 ]. A time course of growth factor release during a seven-day period could probably enable a better understanding of the effects of long-term exposure to an alkaline environment.…”