Evaluation of accuracy and variability of scoring-area-based plaque indices. A laboratory model.
BACKGROUND
Plaque scoring, using a variety of indices and methods, is widely used in clinical dentistry. There is limited information on inter- and intra-examiner variability and almost no data on examiner accuracy.


OBJECTIVE
The aim of this study, was to determine the inter- and intra-examiner variability and accuracy of 15 examiners, of differing plaque-scoring experience, in recording and judging plaque areas from simulated plaque on tooth charts.


METHODS
Plaque, shaded red, was drawn onto tooth charts of 8 simulated "patients" and measured by planimetry by 1 investigator. For each tooth for each "patient", examiners subjectively copied the plaque onto blank charts and scored plaque in 5% increments for the global plaque index. This was repeated on 2 occasions. Drawn plaque areas were determine by the investigator and comparisons made with the actual areas and % scores of plaque.


RESULTS
For both plaque recording methods, intra-examiner variability was low and slightly better than inter-examiner variability. Reproducing plaque areas showed a high level of accuracy in most examiners, as was judging areas in 5% increments, albeit slightly less accurate than area drawing. Overall examiner experience had little influence on judging plaque areas.


CONCLUSIONS
The data suggest that area-based plaque indices can be scored or recorded accurately and with minimal variability within or between examiners. The laboratory model could be used to train and assess examiners.
Shaloub
A
A
Division of Restorative Dentistry, Dental School, Bristol, England.
Addy
M
M
D003773:Dental Plaque / Q000175:diagnosis*; D003774:Dental Plaque Index; D003792:Dental Records / Q000592:standards*; D006801:Humans; D008954:Models, Biological; D015588:Observer Variation; D015203:Reproducibility of Results