Ultrasonographic observation of the circumoral musculature: an in-vivo study.

The aim of the present in-vivo study was to determine whether circumoral musculature could be imaged using an ultrasound with a high frequency probe and to record the changes, if any, in the thickness and shape of the images of the lips occurring amongst normal and different malocclusion states during the relaxed and contracted states. Thirty children with varying classes and types of malocclusion in the age group of 9-12 years were included in this investigation. A real time ultrasound system with a 10 MHz sector scan transducer was used to do the imaging. The results indicated that the circumoral region could be imaged ultrasonographically and that significant changes occurred in the thickness of this muscle in both relaxed and contracted states as well as in varying malocclusion states. Significant increase in muscle thickness was aslo noted in these subjects who were given muscle exercises. Long term observations utilizing this technique in following growth and age related changes will provide a wealth of information for clinical practice in future.