Effect Of Piezoelectric Ceramics On The Proliferation Of Human Gingival Fibroblasts

Purpose: As we know that electric stimulate the ossification, there are many forms of electric stimulation in clinic. Now this is a hot topic that how to make use of the electrostimulation in stomatology to prevent the resorption of remanent alveolar bone. Piezoelectric ceramics is a type of new ceramic, it can make the interconversion of electric energy and mechanical energy. We utilize this effect to prevent the resorption of alveolar bone. But when we apply this new materials to stomatology, it contact the gingiva directly, now we do not know if the piezoelectric ceramics is harmful when it touth the gingiva. The biocompatibility of piezoelectric ceramics is an important problem that we must solve before its clinical application. We choose two typical piezoelectric ceramics as the investigative objects, they are BNT and NKN. We culture the human gingiva fibroblast (HGF) in vitro on the surface of piezoelectric ceramics, and evaluate the effect of piezoelectric ceramics on the proliferation of human gingival fibroblasts by observing morphology,detecting the function of growth and SEM. We compare the effect of piezoelectric ceramics with the traditionary Polymethylmethacrylate (PMMA) on the proliferation of HGF, providing the biologic support for their clinical application.Methods: The study include three parts:1. First of all, we culture the original HGF by the method of tissue mass and enzyme digestion. Observing the morphologic character of original cells by inverted phase contrast microscope , appraising them and going down to the futrue generation . We can draw the cellular growth curve by blood counting ehamber.2. Then polarizing and sterilizing the piezoelectric ceramics. We culture the HGF on the surface of piezoelectric ceramics and PMMA, observing the change of celled form by inverted phase contrast microscope; doing the MTT detection on 1,3,5,7,9 days to see the condition of cell proliferation; detecting the ALP activity on 1,3,5,7 days, comparing the condition of all the groups.3. We inoculate the HGF on the surface of two piezoelectric ceramics and PMMA. We observe them after 6 hours,24 hours,96 hours by SEM. We can see the condition of cell adherency and morphologic change.Results:The HGF grow well on the surface of all the materials, there is no difference among piezoelectric ceramics, PMMA and blank. MTT detection show that there is no significant difference among four groups about cell proliferationm (P>0.05) ,they grow quickly from the third day to the seventh day and reach the peak when they were cultured 7 days, and then they begin to grow slowly. The experiment groups are not different from the control groups concerning the ALP activity (P>0.05), they increase along with the time's prolongation. On the whole it is the same about the cells' adherence to the two piezoelectric ceramics and PMMA. The cyte start to adhering the materials after 6 hours, the cells overgrow on the surface when 96 hours. There is a tendency that the cells grew along the material's ditch .Conclusion: There is no change about cellular morphous,reproductivie activity,ALP activity and adherence ability when we culture the human gingiva fibroblasts on the surface of piezoelectric ceramics. So this new ceramics have no harmful effects to gum when we make use of its piezoelectric effect to stimulating bone growth. The piezoelectric ceramics have good biocompatibility, they are superordinary late-model prosthetic materials. It is potential to apply this kind prosthetic materials in clinic in the future.