Reproducibility of probing depth measurement using a constant-force electronic probe: analysis of inter- and intraexaminer variability

Probing depth (PD) is a commonly used method to determine periodontal disease severity in both treating and evaluating disease progression. Agreement among examiners collecting data in scientific investigations is necessary to establish reliable criteria for determining levels of periodontal attachment loss. The objective of our study was to evaluate inter- and intraexaminer variability of PD measurements among study examiners using a constant force periodontal probe, and to compare the variability of tooth-mean and quadrant-mean. Three examiners, who had been previously trained and calibrated, performed measurements on 20 volunteers. Intra- and interexaminer variability of sites was determined by means of standard error of measurement (SE). Data analysis included determination of error for both quadrant mean and tooth mean. PD measurements for the quadrant-mean were used to calculate the intraexaminer variability, resulting in a mean (SD) value for an SE of 0.40 mm (+/- 0.02). Interexaminer variability for quadrant mean was 0.16 mm (+/- 0.02). For tooth-mean SE, the intraexaminer variability values were equal to 0.38 mm (+/- 0.07), and interexaminer variability equal to 0.24 mm (+/- 0.05). All three examiners participating in our study were able to obtain reliable measurements for PD, using the constant force electronic probe. Reproducibility did not vary appreciably when using the whole quadrant mean compared to the tooth mean. These trained examiners were able to provide reproducible measures under 0.5 mm.