[Diagnostic relevance of OPG and full-mouth X-ray and intraoperative findings].

During surgery the distance between cemento-enamel junction and alveolar limbus as well to the lowest point of the bony defect was measured for 617 tooth surfaces with a periodontal millimeter probe to study the usefulness of OPG and full-mouth X-ray for the detection of periodontal bony defects. The results of different operators did not show any significant differences. Therefore the method of evaluation might be considered reproducible. The average difference between intraoperative measurement and OPG measurement was -0.6 mm and -1.4 mm for the full-mouth X-ray. 50.9% of measurements on the full-mouth X-ray and 59.7% of measurements on the OPG were within the limit of 1 mm. In correlation with the intraoperative measurements the OPG was slightly less reliable for the SZG value at 31 and 41. In the other areas OPG and full-mouth X-ray showed the same correlation with the intraoperative findings. However, on the OPG 13.9% of intraoperatively examined tooth surfaces could not be evaluated since the cemento-enamel junction was not visible. By comparison the failure rate for the X-rays was only 5%. One may therefore conclude that the OPG is of basic usefulness for periodontal X-ray diagnosis, but that additional individual images will be required, since in a considerable percentage of the images the periodontal bone loss is not clearly visible.