The influence of composite resin restoration radiopacity on radiographic diagnosis and decision-making

The objective of this study was to evaluate the influence of the radiopacity of composite resin restorations on the interpretation of phantom radiographic images and to correlate the diagnosis with clinical management. Eighty healthy extracted human third molars were divided into 4 groups (n = 20 each): 3 restorative groups and 1 group of untreated teeth. The radiopacity of the materials was evaluated objectively using 10-mm discs of the composite resins SureFil SDR Flow (SDR), Filtek Bulk Fill Flowable Restorative (Filtek Bulk), and Filtek Z250 XT (Z250). Standard Class II cavities were prepared in the teeth. In the SDR and Filtek Bulk groups, the respective material was placed as a 2-mm base, and the remainder of the cavity was restored with Z250. In the Z250 group, the entire preparation was filled with Z250 composite resin. Ten phantoms of 6 teeth each were created; each phantom included 1 molar selected randomly from each of the 4 groups and 2 healthy premolars. Bitewing radiographs of the phantoms were obtained with a digital phosphor plate system and stored. For the subjective analysis, 5 examiners evaluated each of the molars on the radiographs and established the diagnosis and treatment plan. The radiopacity of the materials was statistically similar (P = 0.413), and there was no statistically significant difference between groups in the interpretation of the images. The radiopacity of the materials met ISO standard 4049/2009. Diagnosis and decision-making were influenced by the radiopacity of the materials. Filtek Z250, which had the lowest radiopacity, was diagnosed correctly more often than SDR, which had higher radiopacity. Filtek Bulk had the highest opacity and the highest percentage of correct diagnoses. In clinical practice, radiographic visualization of restorations and dental structures is essential for establishing a correct diagnosis and treatment plan. A restorative material may be within the established requirements for radiopacity, but on radiographic evaluation it might not be differentiated from mineralized dental tissues.