Abstract
The gingival bleeding index (BI) is frequently used as a sign of gingival disease. However, the normal range and its clinical applications have never been clearly descried. The purpose of the present study was to determine the normal range and to consider the possible clinical applications of the BI. A PS probe was used to keep the measurement pressure constant during determinations of the BI. To define the normal range of BI values, 50 healthy volunteers were instructed to mamtain thorough plaque control for one month before measurement of the BI. The BI value was 17.4±8.3% at baseline, and 6.6±3.1% after one month of plaque control, and the values wad comerted to a normal distibution to a normal distribution. BI values were therefore statistically estimated to range from 0% to about 12% in healthy individuals under adequate plaque control. Determination of the state of plaque control was considered for possible clinical applica-tions of BI. Gingivitis was experimentally induced in 30 healthy volunteers, and the Corelation between the plaque index and BI was tested. The results indicated that continuous plaque control for at least 3 to 7 days was necessary to re-establish the improvement in BI.
The plaque index was hypothesized to indicate the cument status of plaque control, whereas the BI reflects and can be used to determine whether plaque is being continuously controlled. To test our hypothesis, the BI was serially determined in 26 patients who required long-term maintenance.
While the BI values varied at the first visit and after treatment and maintenance, they converged to with in the normal range as plaque control progressed. It was concluded that the normal range of BI values can be used as a variable not only to detect gingival inflammation but to monitor whether adequate plaque control is being maintained. J Jpn Soc Periodontol, 45 : 229-240, 2003.
