Use of furcal bone sounding to improve accuracy of furcation diagnosis.

Accurate diagnosis of periodontal destruction in the furcation region of multi-rooted teeth is a critical component of treatment planning, with different therapeutic approaches chosen based upon clinical determination of the severity of involvement. The current study assessed both vertical and horizontal depths of 274 furcations from 67 patients at three separate time points: by probing prior to anesthesia, by bone sounding after administration of anesthesia, and by direct measurement at the time of surgery. All measurements were made to the nearest millimeter. The mean vertical (1.8 mm) and horizontal (2.16 mm) furcation depths determined prior to anesthesia were significantly less than surgical measurements (2.79 mm and 3.65 mm, respectively). Use of sounding significantly improved the mean accuracy of vertical (2.40 mm) and horizontal (3.11 mm) furcation depth measurements relative to surgical determinations (P = 0.000). Surgical vertical depth was exactly the same as pre-anesthesia probing in 42% of furcations, within +/- 1 mm in 72.3% and within +/- 2 mm in 83.6%. Use of post-anesthesia sounding improved agreement in vertical measurements to 59.5%, 85.7%, and 93.1%, respectively. Surgical horizontal depth was exactly the same as pre-anesthesia probing measurements in 47.1% of furcations, within +/- 1 mm in 68.3% and within +/- 2 mm in 77.4%. Sounding improved agreement of horizontal measurements to 64.2%, 83.6%, and 88.3%, respectively. Underestimation of surgical furcation depths by pre-anesthesia probing was much more common than overestimation. Sounding reduced the percent and degree of underestimation in all furcation types. The data demonstrate the ability of post-anesthesia bone sounding to significantly improve the diagnostic accuracy of furcation invasions.