title: Errors in the assessment of pocket depth in vitro.
abstract: The inaccuracy of the calibration of two Merritt-B probes, old and new style, was investigated. It appeared that the calibration of the Merritt-B "new style" probe was better than the calibration of the old one. The influence of the mode of calibration and the reading of the calibration on pocket depth assessment with a Merritt-B "old style" probe was studied in an in vitro model. The model consisted of 32 aluminium cubes each with a hole in the centre. The holes were 1 mm in cross-section and the depth varied from 0.25 mm to 8 mm in 0.25-mm increments. Results show that pocket depths of 1 mm to 8 mm +/- 0.25 mm generally were read correctly about 90% of the time. This was not true for the 4- and 6-mm areas. When a probe was used where the 4- and 6-mm marks were omitted, pocket depth in that area were read correctly only in about 60% of instances. This difference disappeared when the 4- and 6-mm marks were added. Results of measuring the half millimeter values showed that generally 80% were recorded as the lower whole millimeter.
mesh_terms: D003762:Dental Instruments / Q000592:standards; D003951:Diagnostic Errors; D005069:Evaluation Studies as Topic; D006801:Humans; D010514:Periodontal Pocket / Q000473:pathology*; D010517:Periodontics / Q000295:instrumentation; D010518:Periodontitis / Q000473:pathology*; D012107:Research Design