Evaluation of biocompatibility of light-curing of pulp capping material on subcutaneous tissues of rats

The purpose of this study is to compare TheraCal LC which is a resin-containing material that are used in pulp capping treatment with ProRoot MTA, another pulp capping material, in terms of their biocompatibility. In this study, 4-month old 18 male wistar rats, whose weights range between 450 gr and 700 gr, were used to examine biocompatibility. Each polyethylene tubes with 1.5 mm inner radius cut into 10mm-length pieces. 3 different tubes, ProRoot MTA, TheraCal LC and control group, were prepared to place into dorsal region of each animals. ProRoot MTA prepared with manufacturer's instructions were placed in the polyethylene tube via Ward's Carver. TheraCal LC is transferred to tubes by its own injector and hardened by light. Also, tubes of control group were left as empty. Those tubes implemented to subcutaneous tissues of dorsal regions of the rats. Six of the rats are killed by euthanasia 7 days after operation while another 6 ones killed 30 days after it. Also, the remaining 6 rats were killed similarly after 90 days of the implementation. Implemented materials were extracted with some healthy ambiance tissues. After that, fixation of extracted samples were done in 10% buffered formalin solution in 24-48 hours. Samples of connective tissues were obtained from each polyethylene and these samples were embed to paraffin blocks. Then, 5-µm sections of tissue samples were stained by haematoxylin and eosin. 40x, 100x, 200x, and 400x zooming were done by light microscope (Olympus Bx50) for histological examination. Tissue reactions around polyethylene tubes were scored in these histological examinations. In 7- days period, average scores of Control, ProRoot MTA and TheraCal LC groups were calculated as 2.00, 2.33 and 1.67, respectively. It was obtained that there was no significant difference in the amount of inflammatory reactions for this period (p>0.05). Average scores of Control, ProRoot MTA and TheraCal groups were found as 0.33, 1.00 and 1.17, respectively, for 30-days period. Also, no significant difference was noted between groups in statistical evaluation (p>0.05). For 90-days period, average scores of Control, ProRoot MTA and TheraCal LC groups were measured as 0.00, 0.17 and 0.00, respectively. No difference was found among groups in statistical evaluation. A significant statistical difference between different periods were observed for each experimental group and control group (p≤0.05). The amount of inflammation that are determined after 30th day was less than the one determined after 7th day. Also that amount decreased more on 90th day. According to the results of this study, inflammatory responses of Theracal LC and ProRoot MTA were decreased. Hence, it can be said that both of these pulp capping materials might be biocompatible. Key Words: Pulp capping, MTA, Theracal LC, Biocompatibility, Subcutaneous