OBJECTIVEThe purpose of this study was to explore the possible principles for remodeling of periodontal tissues under 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.

METHODShPDLFs were cultured in vitro. The 4 - 7th generation of hPDLFs were undergone mechanical stretching. All cells were 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 3 000 mustrain. Flow cytometry (FCM) was used to examine the ratio of DNA (S%) and the index of proliferation(PI).

RESULTSMechanical force would lead to the change of hPDLFs proliferation. Within the experiment, both 1 000 mustrain and 2 000 mustrain could increase the proliferation index (PI) (P < 0.05). While under 3 000 mustrain, DNA synthesis was significantly decreased( P < 0.05).

CONCLUSIONSome range of mechanical stretching accelerates hPDLFs proliferation. This research discusses the remodeling process of periodontal tissues undergoing the mechanical stretching on cytological view, and it makes a basement for further revealing the mechanical strain induced periodontal biological principles. Also it provides a useful direction for clinical orthodontic therapy.