Cytotoxicity, biocompatibility and calcium deposition capacity of 45S5 bioglass experimental paste and Bio-C Temp: in vitro and in vivo study using Wistar rats

Abstract

Objectives To evaluate cytotoxicity, biocompatibility, calcium deposition, and collagen maturation of 45S5 bioglass experimental paste and Bio-C Temp compared to calcium hydroxide (Ca(OH)2) paste. Materials and methods 45S5 bioglass and Ca(OH)2 powder were mixed with distilled water (ratio 2:1) and Bio-C Temp is ready-for-use. Dental pulp cells were exposed to material extracts (½ and ¼ dilutions; 24, 48, 72h) for MTT and live/dead analysis. Polyethylene tubes filled with 45S5 bioglass, Bio-C Temp, and Ca(OH)2 pastes, or empty for control, were implanted on the dorsum of 16 rats. After 7 and 30 days (n=8/period), the rats were euthanised and the specimens processed for haematoxylin-eosin staining, von Kossa (vK) technique, and picrosirius red (PSR), or without staining for polarized light birefringence analysis (PL). Statistical analysis was applied (p<0.05). Results In vitro, there was no difference in cell viability among the Ca(OH)2, 45S5 bioglass and control, in all periods and extracts dilutions (p>0.05). Bio-C Temp was more cytotoxic than control in all periods and dilutions (p<0.05). In addition, it was more cytotoxic than 45S5 bioglass in 24 hours in 1:2 and 1:4 dilutions, and in 48 hours in the 1:2 dilution (p<0.05). In vivo, there was no difference between groups for any of the periods (p>0.05). However, there was a reduction in inflammation from 7 to 30 days for all groups. The fibrous capsule was thick for all groups at 7 days, and thin at 30 days. All materials showed positive structures for vK and birefringent in PL, which did not occur with the control. At 7 days, there were more immature fibers in control and 45S5 bioglass compared to other materials (p<0.05); at 30 days, 45S5 bioglass had more immature than mature fibers, being different from the other groups (p<0.05). Conclusions Bio-C Temp presented cytotoxicity superior to the experimental 45S5 bioglass and Ca(OH)2 pastes. On the other hand, the three pastes showed biocompatibility and ability to induce calcium deposition. In addition, the experimental bioglass paste allowed a marked and continuous proliferation of collagen fibers. Clinical relevance Bioglass-based intracanal medications are potential substitutes for traditional intracanal medications