Abstract: A noninvasive probe effects a method of measuring the depth of the periodontal pocket along an outer surface of a tooth wherein the depth is measured from an outer gum ledge tooth surface adjacent a tooth outer surface to the bottom of the pocket where the bone surface joins the tooth outer surface. The probe comprises an elongated handle portion, a neck portion and a head portion with each said portion having a respective longitudinal axis. The head portion includes an outer tip section and a transducer section connecting the tip section to the neck portion. The outer tip section includes a gum contacting end surface having a structural configuration effective to completely engage the outer gum ledge surface adjacent the tooth outer surface. The probe is used in combination with an assembly comprising a mechanism for establishing a first ultrasound pulse travel path having a fixed, reflective delay time and a second ultrasound pulse travel path having a variable, reflective delay time.