THE STIMULATION OF BONE-FORMATION IN-VITRO BY THERAPEUTIC ULTRASOUND

A controlled study was performed to evaluate the effects of different ultrasound (US) intensities on 5-day-old mouse calvaria bone in tissue culture, A special technique to apply the US was developed, and the f ollowing parameters were measured: collagen and noncollagenous protein (NCP) synthesis (bone formation), and temperature change, It was foun d that ultrasound at 0.1 W/cm(2) (SATA), pulsed 1:4, 3 MHz, 5 min, sig nificantly stimulates bone formation (i.e., the synthesis of collagen and NCP) (p < 0.001 and p < 0.01), However, pulsed ultrasound at highe r doses (1.0-%.0 W/cm(2) (SATA), pulsed 1:4, 3 MHz, 5 min) significant ly inhibited the synthesis of both collagen and NCP (p < 0.05), The te mperature measurements showed a maximum rise of 1.8 degrees C [at 2.0 W/cm(2) (SATA)] and no detected rise at 0.1 W/cm(2) (SATA), suggesting that the effects in this study were primarily nonthermal, These resul ts may reflect the healing effect of US on fractures and osteoradionec rosis and I:reinforces the use of low intensity US regimens [0.1 W/cm( 2) (SATA)] in clinical practice. (C) 1997 World Federation for Ultraso und in Medicine & Biology.