Reliability of filter-strip sampling of gingival crevicular fluid for volume determination using the Periotron

This study explored gingival cervicular fluid (GCF) volumes as measured by the Periotron in an attempt to find a more objective measure of gingival inflammation that could be used in dental compliance studies. The first step in this process was to assess the reliability of the method of collecting and determining GCF volumes as described by the manufacturer. Collections of GCF from both the buccal and lingual surfaces of 6 teeth from 18 subjects with good to moderate plaque accumulation was accomplished. At a later time these same surfaces were retested for a comparison with the initial value for reliability determination. We found that only 23% of the tooth surface pairs varied by less than 20% and 57% of these pairs differed by at least 50%. These values were similar for both good and moderate plaque accumulation subjects. In these subjects, reliability measurements at individual tooth surfaces did not approach acceptable levels of reliability. However, when the GCF values from the 12 tooth surfaces were averaged for each subject, differences between the two measurements improved markedly. Sixty-one percent of these subject pairs differed by less than 20%. Therefore, the average GCF value from subjects with good to moderate plaque accumulations may be compared with reasonable accuracy.