Biocompatibility of NeoPUTTY™ versus TheraCal PT® and TheraCal LC® pulp-capping materials, and tissue reaction following subcutaneous implantation in rats: Histological and molecular investigation.

Abstract

Background: Materials used for vital pulp therapy should support the natural healing and regeneration of the dental pulp. Ideally, these materials should be biocompatible, bioactive, non-toxic, and noncarcinogenic. Although numerous medicaments are currently available on the market, none fully meet all the criteria required for an ideal material. In recent years, calcium silicate-based materials, known for their bioactivity and biocompatibility, have gained widespread use in dental practice.

Objectives: This in vivo study investigated the tissue response and biological characteristics of mineral trioxide aggregate (MTA) - NeoPUTTY™, as well as TheraCal PT® and TheraCal LC®, following subcutaneous implantation in rats.

Material and methods: Twenty adult male albino rats were randomly assigned according to the sacrifice time (2 or 4 weeks) into 2 equal groups, which were further subdivided into 4 subgroups based on the material used. Four incisions were made on the back of each rat to create 4 pockets, into which polyethylene tubes were implanted. Three tubes were filled with biomaterials, while the 4th was left empty as a control. After sacrifice, the samples were analyzed histopathologically, histomorphometrically, and for gene expression of vascular endothelial growth factor (VEGF) and interleukin-6 (IL-6).

Results: Moderate inflammation was the predominant tissue response to NeoPUTTY. TheraCal LC demonstrated the formation of a thick connective tissue capsule with moderate chronic inflammatory cell infiltration. In contrast, TheraCal PT showed a mild inflammatory response and a lower area percentage of collagen fibers in the capsule as compared to NeoPUTTY and TheraCal LC. NeoPUTTY and TheraCal LC were associated with higher VEGF and IL-6 expression levels than those observed in the TheraCal PT and control groups.

Conclusions: TheraCal PT appears to be a promising material for direct pulp capping, owing to its favorable biocompatibility when tested in vivo in comparison with NeoPUTTY and TheraCal LC. These findings may assist clinicians in selecting appropriate materials for direct pulp capping, as TheraCal PT demonstrated greater biocompatibility with respect to its effects on the surrounding tissues.