We have developed an ultrasonic technique for imaging periodontal structures which allows accurate measurements of disease activity without the need for ionizing radiography or manual periodontal probing. It promises reduced variability and improved ease of use, in comparison to conventional manual periodontal probing, and is the first step to establish the ultrasound periodontal probe as a clinically-valuable tool for patient assessment and the first non-invasive measure of periodontal disease activity. We have gathered data from cadaver samples using a prototype intra-oral ultrasound instrument, and have compared the ultrasound scans against conventional manual probing subsequently performed on the annotated cadaver samples.