In Vivo Evaluation of the Bioactivity of a Tri-Calcium Silicate Cement, An Experimental Animal Approach

Objectives: Biodentine, a new experimental Ca3SiO5-based restorative cement, intends to be a glass ionomer cement and composite-resin substitute in restorative dentistry. Our aim was to evaluate in vivo the bioactive effects of Biodentine as assumed from the formation of reactionary and reparative dentins in a in vivo animal model. Methods: Using 6-7 week-old rat, half-moon cavities were prepared on the mesial aspect of the first maxillary molar with and without pulp exposure. The cavities were i) left unfilled (sham group) or ii) filled either with a glass-ionomer cement (control group) or iii) with Biodentine (experimental group). The rats were killed by perfusion through the heart with the fixative solution 8, 15 or 30 days, and 3 months after the dental treatment. Block sections including the three maxillary molars were demineralised and processed for light microscopy. After histological processing measurements were done on micrographs. Results: In the absence of pulp exposure, after 8 days a slight inflammatory reaction was seen in each group of rats. In the Biodentine group, a dentin layer of reactionary dentin started to be formed by the odontoblasts, slightly thicker than in the 2 other groups. After 15 days, a tendency to spontaneous repair was observed in the pulps of the sham and control groups. In the Biodentine group, close to the cavity, a 40-80 ìm thick layer of reactionary dentin protected the pulp. In the Biodentine group, after one month, the mesial part of pulp was partially filled with a homogenous dentin-like material (160ìm) whereas the rest of pulp appeared normal. Reactionary dentin was also seen along the root canal. After three months, the thickness of a homogenous reactionary dentin was unchanged compared with the 1 months reaction. After pulp exposure and direct pulp capping, Biodentine-induced reparative dentin was observed, displaying both a lack of cytotoxicity and bioactive properties. Conclusions: The present data i) suggests that Biodentine displays novel bioactive properties, ii) stimulates the formation of reactionary dentin in the rat molar model shortly after a switch on, iii) there is actually a “switch off”, keeping the remaining pulp alive, iv) used as direct capping agent Biodentine seems to be efficient in the formation of reparative dentin. For ref. see: Boukpessi T, Septier D, Goldberg M. Animal studies, in “Biocompatibility and cytotoxic effects of dental composites”, M. Goldberg ed. Coxmoor, Oxford, UK2009, pp 200-203.