title: Influence of radiopacity of dental composites on the diagnosis of secondary caries: the correlation between objective and subjective analyses.
abstract: This study aimed to objectively evaluate the radiopacity of different dental composites and their subjective influence on diagnosing secondary caries-like lesions and how these results correlate. For objective analysis, three resin specimens (1 mm thick, with a 4-mm internal diameter) were made with four composites: 1) Charisma; 2) Filtek Z250; 3) Prisma AP.H; and 4) Glacier. Three human teeth were selected and then mesio-distally sectioned (1 mm thick) to make the dental specimens. An aluminum (Al) wedge (12 steps, 1 mm thick, 99.8% purity) was used as an internal standard to calculate the radiopacity. For subjective analysis, 20 human teeth were selected and then prepared with a mesio-occluso-distal (MOD) inlay cavity, with half the teeth receiving a round cavity to simulate the carious lesion. The MOD was restored using the composites at four different times. Standardized radiographs were acquired and then digitized (300 dpi and eight-bit TIFF) for both analyses. A histogram objectively measured the pixel intensity values of the images, which were converted into millimeters of Al using linear regressions. Eight observers subjectively evaluated the images using a five-point rating scale to diagnose the caries. The data were statistically analyzed using the Student t-test, the Kappa test, diagnostic testing, and the Pearson correlation coefficient (α=0.05). All materials showed radiopacity values compatible with dental tissues (p>0.05); Glacier was similar to dentin and Prisma AP.H was similar to enamel, while the remaining materials showed a middle radiopacity. Prisma AP.H and Glacier differed (p<0.05) in relation to their accuracy to caries diagnosis, with Glacier having greater accuracy. There was a correlation between objective and subjective analyses with negative linear dependence. An increase in the material's radiopacity could have a subjectively negative influence on the diagnosis of secondary caries; thus, an ideal radiopacity for a dental composite is closer to the dentin image and produces similar attenuation to X-rays than does dentin.
authors.forename: A D
authors.initials: AD
authors.lastname: Cruz
authors.forename: R G
authors.initials: RG
authors.lastname: Esteves
authors.forename: I A V P
authors.initials: IA
authors.lastname: Poiate
authors.forename: P P
authors.initials: PP
authors.lastname: Portero
authors.forename: S M
authors.initials: SM
authors.lastname: Almeida
mesh_terms: D003188:Composite Resins; D003731:Dental Caries / Q000000981:diagnostic imaging*; D003793:Dental Restoration, Permanent; D006801:Humans; D011861:Radiography, Dental; D019279:Resin Cements
chemical_list: C084111:Charisma composite resin; D003188:Composite Resins; C444701:Filtek Z250; D019279:Resin Cements; C471182:glacier hybrid composite; C073466:Prisma APH