Effect of low frequency ultrasound waves on the morphology and viability of cultured human gingival fibroblasts.

Objectives: The aim of this study was to investigate the effect of the vibration amplitude of mechanical ultrasound waves (27 kHz) on the viability and morphology of human gingival fibroblasts (hGFs) when cultured on a biomaterial substrate. Method: hGFs were seeded on tissue culture plates (TCPs) and an Ti6Al4V titanium alloy surface in two groups for three days and seven days of cell culture. The cells were subjected to three vibration amplitudes for 20 min each day. Scanning electron microscope (SEM) images were used to characterize cell morphology. Results: Experiments showed that hGF cells became detached from their plates at a vibration amplitude comparable to an intensity of 260 mW/cm2. In addition, hGfs that received a vibrational amplitude comparable to an intensity of 50 mW/cm2 underwent significant proliferation proliferated significantly; however, cells receiving higher amplitudes suffered from adverse effects. Conclusions: SEM images of hGFs on titanium disks at vibration amplitude comparable to an intensity 50 mW/cm2 showed a remarkable hexagonal architecture, which we refer to as a honeycomb pattern. On day 6 the observed hGFs on TCPs, proliferated at a higher rate and new cells attached uniformly on the existing layer of cells. These data indicate the effect of cellular tissue as a substrate on the growth of new hGFs under low-intensity ultrasound.