Many people are familiar with the pocket depth measurements that occur in the dentist’s office. The dental technician pokes her periodontal probe into a patient’s gum line to measure how deep the probe will go. This is repeated tooth by tooth until the entire mouth is covered. Although inexpensive, probing depth measurements are error prone and suffer from poor reproducibility, largely due to variation in probing force. Indeed, a recent meta-analysis showed that a range of a variation of 20-fold. Other error sources include variation in the insertion point, probe angulation, the patient’s overall gingival health, and the presence of calculus. Thus, the examination is subject to large errors with inter-operator variation as high as 40%. These error sources can result in poor patient treatment and, hence, poor patient outcomes. This variation also compromises epidemiologic studies and makes it difficult to compare outcomes among dentists or among populations. Given these limitations, new tools are urgently needed to improve this procedure.