Effect of ultrasound multiplied by non-pathogenic infection on the collagen tissue formation

[Contribution of low-intensity pulsed ultrasounds to bone regeneration]

A maxillo-facial surgeon manages patients with bone defects due to trauma, malformations or of iatrogenic origin. The surgical management has potentially deleterious effects and its cost for society is increasing. Hence, it is crucial to develop techniques stimulating bone growth, stimulating the regeneration of a fracture or filling bone deficit. Ultrasounds (US), vibrations of the same nature as sound but with frequencies above the highest audible frequency for men (above 20 kHz), are used in many fields, particularly in medicine, usually at frequencies of around 0.5 to 5 MHz (million cycles per second). Their biological effects are not fully understood yet, but it is well known that US have effects on organic tissues when their mechanical energy is converted into thermic energy. These effects induce vasodilation and modification of membrane permeability. Several publications present the benefit of US for the stimulation of bone regeneration after a fracture. We present an overview of current knowledge on the effect of pulsed ultrasound on craniofacial bone regeneration, with study results conducted within Inserm unit U1032 in Lyon, the current reference lab on this issue.