Rat subcutaneous tissue response to calcium silicate containing different arsenic concentrations

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Toxicology

Background:

• Dental cements are widely used in endodontics and restorative dentistry.
• Understanding the biocompatibility of these materials, particularly concerning their elemental composition, is crucial for clinical success.
• Arsenic, a component in some older dental materials, has raised concerns regarding potential toxicity and inflammatory responses.

Purpose of the Study:

• To investigate the subcutaneous tissue response in rats implanted with polyethylene tubes filled with different dental cements containing varying concentrations of arsenic.
• To evaluate the morphometric and descriptive characteristics of the inflammatory response and tissue repair.
• To determine if there is a correlation between arsenic concentration and the observed inflammatory reactions.

Main Methods:

• Dental cements (GMTA Angelus, Portland cements) with known arsenic concentrations were prepared.
• Polyethylene tubes filled with these cements were implanted subcutaneously into 36 rats.
• Tissue samples were collected at 15, 30, and 60 days post-implantation for descriptive and morphometric analysis.
• Histological evaluation focused on inflammatory cells, collagen fibers, fibroblasts, and blood vessels.
• Statistical analysis was performed using the Kruskal-Wallis and Dunn's Multiple tests.

Main Results:

• Atomic absorption spectrophotometry revealed arsenic concentrations ranging from 0.69 mg/kg (WPC Irajazinho) to 18.46 mg/kg (GPC Minetti).
• All specimens showed neoformation of connective tissue (fibrocellular capsule) by 60 days.
• GPC Minetti (18.46 mg/kg arsenic) elicited the most severe inflammatory reaction, while MTA Angelus (5.01 mg/kg arsenic) and control groups showed the least.
• No direct linear relationship was found between arsenic concentration and inflammatory intensity across all tested materials.

Conclusions:

• The study suggests that factors beyond arsenic concentration influence the inflammatory response to dental cements.
• High arsenic content, as seen in GPC Minetti, can lead to severe inflammation, particularly at later time points.
• MTA Angelus demonstrated favorable biocompatibility, resulting in minimal inflammatory reactions compared to the other tested Portland cements.