Histological evaluation of tissue reactions to newly synthetized calcium silicate- and hydroxyapatite-based bioactive materials - In vivo study

Abstract

Introduction/Objective Development of materials which could be used as biological bone substitutes is one of the most valuable and active fields of biomaterial research. The goal of the study was to research the reaction of tissue on calcium silicate-(CS) and hydroxyapatite-based (CS-HA) newly synthesized nanomaterials, after being implanted into the subcutaneous tissue of a rats and direct pulp capping of rabbit teeth. Methods The tested materials were implanted in 40 Wistar male rats, sacrificed after seven, 15, 30, and 60 days. The direct pulp capping was performed on the teeth of rabbits. Cavities were prepared on the vestibular surface of the incisors. The animals were sacrificed after 10 and 15 days. The control material was mineral trioxide aggregate (MTA). Histological analysis covered the tracking of inflammatory reaction cellular components, presence of gigantic cells, and necrosis of the tissue. Results Seven days after the implantation, the strongest inflammatory response was given by the MTA (3.3 +/- 0.48), while CS and CS-HA scored 3 +/- 0.71. After 60 days, the rate of inflammatory reactions dropped, which was the least visible with CS-HA (0.2 +/- 0.45). The least visible inflammatory reaction of the rabbits pulp tissue was spotted with the CS (1.83 +/- 0.75), than with the MTA and CS-HA (2.67 +/- 1.53, 3 +/- 0.63). Conclusion The newly synthesized materials caused a slight reaction of the subcutaneous tissue. CS-HA showed the best tissue tolerance. Nanostructural biomaterials caused a slight to moderate inflammatory reaction of the rabbits pulp tissue only in the immediate vicinity of the implanted material.