Combination instruments for probing caries and parodontium. WHO probe was developed for CPITN method. Diagnosis: 0 = healthy 1 = bleeding during probing 2 = supra- and/or subgingival calculus, filling or crown excesses 3 = gingival pockets to 5 mm 4 = pockets deeper than 6 mm Most explorers and periodontal probes are available also in single-ended designs.