Abstract:

Objective　The purpose of this studywas to explore the possible principles for remodeling of periodontal tissues un- der mechanical stretching by investigating the effects of intermittent mechanical stretching delivered by a new invented type of cell stress machine on the proliferation kinetics of the human periodontal fibroblast cells (hPDLFs)in vitro.Methods　hPDLFs were culturedin vitro. The 4~7th generation of hPDLFswere undergone mechanical stretching. All cellswere grouped as strained and unstrained (controls). Strained groups cells were gathered after 2,4 and 6 hours with the stress 1 000,2 000 and 3 000μstrain. Flow cytometry (FCM) was used to examine the ratio of DNA(S%) and the index of proliferation(PI).Results　Mechanical force would lead to the change of hPDLFs proliferation. Within the experiment, both 1 000μstrain and 2 000μstrain could in- creasethe proliferation index(PI)(P<0·05). While under 3 000μstrain, DNA synthesis was significantly decreased(P< 0·05).Conclusion　Some range of mechanical stretching accelerates hPDLFs proliferation. This research discusses the remodel- ing process of periodontal tissues undergoing the mechanical stretching on cytological view, and itmakes a basement for further re- vealing the mechanical strain induced periodontal biological principles. Also it provides a useful direction for clinical orthodontic therapy.

Key words: strain, human periodontal fibroblast cells, proliferation