The influence of composite resin restorations and lining on radiographic diagnosis and decision-making: an in vitro investigation.

The objective of this study was to evaluate the influence of resin-based restorations on the interpretation of digital and conventional radiographic images and to correlate the proposed diagnosis with decision-making. Class II cavities were prepared in one of the proximal surfaces of extracted human molars. Teeth were divided into five groups (n = 10) according to the restoratives used: Natural Flow (NF) and Filtek Supreme (FS); Filtek Flow (FF) and FS; Tetric Flow (TF) and FS; Protect Liner F (PLF) and FS; and FS alone. Bitewing radiographs were taken using conventional and digital systems. Subjective analysis was performed for each surface: no restoration; restored teeth; or restored teeth with gap. Based on the given diagnosis, clinical conduct was then indicated. Material radiopacity was determined according to ISO 4049. A Fisher exact test evaluated the influence of the restoratives on the diagnosis. Means were compared using ANOVA and the Games-Howell test. A Friedman test was used to analyze the influence of the systems on the diagnosis, and a binomial test was used to analyze the association between the presence of gaps and the decision to replace the restoration (P = 0.05). For each system, TF+FS was significantly associated with a high percentage of correct diagnoses. The opposite was the case for PLF+FS, which differed from all other groups. Radiographic systems presented similar behaviors, except for NF+FS. Apart from PLF, adequate radiopacity was observed. Diagnosis was influenced by restorative materials, regardless of the radiographic system used. The low radiopacity of PLF led to a greater number of erroneous diagnoses. Moreover, the decision-making process was influenced strongly by the given diagnosis.