Biological effect of Egyptian Propolis on BHK cell line and on dental pulp tissue (An In vitro And In vivo study)

Background: Propolis is a natural material with different biological activities such as anti-inflammatory, antibacterial and antifungal action. The aim of the present work was to evaluate biocompatibility of Egyptian Propolis by using two methods of assessment: the invitro test using Baby hamster kidney cell (BHK) cell line and the invivio study on dental pulp of dogs. Materials & Methods: For the invitro study: ethanol extract of propolis (EEP) was prepared at a concentration of 1mg/ml. A suspension of the cultured BHK cells was placed in 96 multi-well dishes and divided into two groups : control group containing BHK cells without EEP and propolis group containing BHK cells with EEP at a concentration of 1mg/ml. Cell counting was performed at 24 hours,
72 hours and at the seventh day. Mean values were then calculated for each group. The results were then statistically analyzed using ANOVA test. Scanning Electron Microscopy (SEM) was done for both groups at the seventh day. For the invivo study, 2 young healthy adult dogs, of comparable age, 1-1.5 years old and complete set of permanent dentition were used in this study. The canine and first molar of each quadrant were used in this study and second upper molars of each dog was also prepared, forming a sum of 10 sound teeth. A standardized class V cavity was prepared on the facial surface of the selected teeth. All the cavities were restored with resin modified glass ionomer while in half of them Propolis was used as lining material under resin modified glass ionomer. At the end of experimental period after 6 months, dogs were sacrificed. Microsections with 5 μm width were prepared and stained with hematoxylin and eosin. Results: invitro study results showed a significant increase in number of BHK cells of propolis group at 72 hours and at the seventh day when compared to the control group. Scanning electron microscopic examination of BHK cells showed increase in density of BHK cells of propolis group as compared to cells of the control group. Both groups showed uniform spreading and attachment of cells to root surface. Examination of the decalcified stained sections of teeth of propolis group revealed no inflammation, normal tubular pattern of dentin and arrangement of odntoblasts in multiple layers . Presence of line of demarcation between primary and secondary dentine. Conclusion : Egyptian propolis stimulated growth and proliferation of BHK cell in vitro and showed no inflamatory effect on pulp tissue invivo.These results collectively proved the biocomptability and good biological properties of Egyptian propolis and support the application of Egyptian propolis in numerous fields of dentistry.