Comparison of visual inspection and different radiographic methods for dentin caries detection on occlusal surfaces

Objectives: The aim of the present study was to assess the validity of the digital phosphor plate radiographic technique (Gendex Dental Systems) on occlusal surfaces in comparison with visual examination and conventional E- and F-speed films. Methods: The study material consisted of 54 non-cavitated third molars with a range of appearances, including apparently sound surfaces. Each surface was visually examined (VI) according to the criteria established by Ekstrand et al. Three radiographic images (E-speed, F-speed, digital phosphor plate film) were taken of each molar. The standardized radiograph technique used an alignment fixture to reproduce the focus-to-object distance as well as the object-to-film distance. Afterwards each tooth was cut into sections in the buccolingual direction with a microtome saw, and caries extension was assessed using light microscopy (LM) and microradiography (MR). The statistical analysis included the calculation of sensitivity (SE), specificity (SP) and A(z) values. Results: The following validity parameters were found for the tested diagnostic methods on the dentin caries level: VI/LM, 68.0 SE/93.1 SP/0.698 A(z); VI/MR, 68.2/87.5/0.751; E-speed/LM, 76.0/78.6/0.637; E-speed/MR, 77.3/74.2/0.681; F-speed/LM, 64.0/67.9/0.507; F-speed/MR, 68.2/67.7/0.594; Gendex/LM, 60.0/85.7/0.629; and Gendex/MR, 59.1/80.6/0.586. Conclusion: The methods used showed different levels of validity: E- and F-speed films were linked to higher sensitivity values, whereas a higher specificity was recorded for the tested imaging plate system. In accordance with the diagnostic performance, the digital system can be recommended for practical use and potentially help prevent overtreatment thanks to its high SP. Dentomaxillofacial Radiology (2009) 38, 452-457. doi: 10.1259/dmfr/34393803