Explorers: For diagnosing calculus and caries and exploration of pockets, restorations and furcations. Most explorers and periodontal probes are available also in single-ended designs. Explorers-Periodontal Probes: Combination instruments for probing cariesand parodontium. Furcation Probes: For probing the extent and depth of furcation lesions. For probing furcation lesions from different angles, both in the upper and in the lower jaw region.