Prediction of the extent of caries in pit and fissure lesions in a field trial in the west of Scotland.

A field trial is in progress in which 14 community clinical dental officers and 19 general dental practitioners were asked to record the actual extent of fissure lesions and how this compared with the cavity size they expected. Participating operators worked under their normal conditions of daily practice. Forty-eight to fifty-seven percent of 644 prepared cavities were of the expected size upon investigation, depending on the diagnostic technique used. Greater accuracy was achieved among the smaller cavities (58-75% as expected) than with the larger (52-69% larger than expected). More difficulty with cavity size prediction occurred with the lower right first molar than with the other first molar teeth and with both mandibular second molars compared to the maxillary molars. Comparisons between the accuracy of cavity size prediction achieved using a visual inspection in combination with the probe and a visual inspection alone showed no significant difference. Under the conditions of this field trial, considerable difficulties were experienced in predicting cavity size accurately.