Wear Characteristics of Dental Ceramic CAD/CAM Materials Opposing Various Dental Composite Resins

Abstract

The aim of this study was to evaluate the wear properties of opposed dental ceramic restorative CAD/CAM materials and several posterior direct restorative composite resins. Three kinds of dental ceramics CAD/CAM materials (monolithic zirconia, lithium disilicate, leucite) and four dental composite resins-that is, MI Gracefil, Gradia Direct P, Estelite Σ Quick, and Filtek Supreme Ultra-were used in this study. For each of the 12 groups (three ceramics × four composite resins), five each of a canine-shaped ceramic specimen and a cuboidal shape opposing composite resin were prepared. All of the specimens were tested in a thermomechanical loading machine (50 N, 100,000 cycles, 5/55 °C). Wear losses of ceramic specimens and composite resin specimens were evaluated using a three-dimensional profiling system and an electronic scale, respectively. Statistical analyses were performed using the Kruskal-Wallis test and Mann-Whitney U test with Bonferroni's correction. Zirconia showed significantly less volumetric loss than lithium disilicate or leucite regardless of composite resin type (p > 0.05/3 = 0.017), and that Estelite Σ Quick showed significantly more weight loss than Filtek Supreme Ultra, MI Gracefil, or Gradia Direct P regardless of ceramic type (p > 0.05/6 = 0.083). Zirconia showed less volumetric loss than lithium disilicate or leucite. Some composite resins opposing ceramics showed considerable weight loss.

Keywords: composite resin; leucite; lithium disilicate; monolithic zirconia; wear.

Figure 1

Flow-chart of the study.

Figure 2

(A) Preparation of the dental ceramic specimen (from left, monolithic zirconia; lithium disilicate; leucite). (B) Dental ceramic specimen embedded in autopolymerizing acrylic resin mold. (C) Preparation of the dental composite specimen (from left, MG, MI Gracefil; GD, Gradia Direct P; EQ, Estelite Σ Quick; FT, Filtek Supreme Ultra).

Figure 3

Measuring volumetric loss of ceramic specimens using three-dimensional images: (A) STL file of the ceramic specimen before wear testing. (B) STL file after wear testing. (C) Wear volume measurement; wear volume (blue part; top) = STL file before wear (bottom)-STL file after wear (middle).

Figure 4

Volumetric losses of ceramic specimens (mm³ × 10⁻³). (A) Mean volumetric loss of ceramic regardless of composite resin type. (B) Mean volumetric loss of ceramic according to composite resin type. MG, MI Gracefil; GD, Gradia Direct P; EQ, Estelite Σ Quick; FT, Filtek Supreme Ultra. * Statistical significance.

Figure 5

Volumetric losses of ceramic specimens (mm³ × 10^-3). (A) Volumetric losses of ceramics when opposing to MG. (B) Volumetric losses of ceramics when opposing to GD. (C) Volumetric losses of ceramics when opposing to EQ. (D) Volumetric losses of ceramics when opposing to FT. ZMG, zirconia opposing MI Gracefil; DMG, lithium disilicate opposing MI Gracefil; LMG, leucite opposing MI Gracefil; ZGD, zirconia opposing Gradia Direct P; DGD, lithium disilicate opposing Gradia Direct P; LGD, leucite opposing Gradia Direct P; ZEQ, zirconia opposing Estelite Σ Quick; DEQ, lithium disilicate opposing Estelite Σ Quick; LEQ, leucite opposing Estelite Σ Quick; ZFT, zirconia opposing Filtek Supreme Ultra; DFT, lithium disilicate opposing Filtek Supreme Ultra; LFT, leucite opposing Filtek Supreme Ultra. * Statistical significance.

Figure 6

Weight losses of composite resin specimens (mg): (A) Mean weight loss of composite resin according to ceramic type. (B) Mean weight loss of composite resin regardless of ceramic type. MG, MI Gracefil; GD, Gradia Direct P; EQ, Estelite Σ Quick; FT, Filtek Supreme Ultra. * Statistical significance.

Figure 7

Weight losses of composite resin specimen (mg): (A) Weight losses of MG when opposing to ceramics; (B) Weight losses of GD when opposing to ceramics; (C) Weight losses of EQ when opposing to ceramics; (D) Weight losses of FT when opposing to ceramics. ZMG, zirconia opposing MI Gracefil; DMG, lithium disilicate opposing MI Gracefil; LMG, leucite opposing MI Gracefil; ZGD, zirconia opposing Gradia Direct P; DGD, lithium disilicate opposing Gradia Direct P; LGD, leucite opposing Gradia Direct P; ZEQ, zirconia opposing Estelite Σ Quick; DEQ, lithium disilicate opposing Estelite Σ Quick; LEQ, leucite opposing Estelite Σ Quick; ZFT, zirconia opposing Filtek Supreme Ultra; DFT, lithium disilicate opposing Filtek Supreme Ultra; LFT, leucite opposing Filtek Supreme Ultra.

Figure 8

Representative SEM images of composite resin surfaces: ZMG, zirconia opposing MI Gracefil; DMG, lithium disilicate opposing MI Gracefil; LMG, leucite opposing MI Gracefil; ZGD, zirconia opposing Gradia Direct P; DGD, lithium disilicate opposing Gradia Direct P; LGD, leucite opposing Gradia Direct P; ZEQ, zirconia opposing Estelite Σ Quick; DEQ, lithium disilicate opposing Estelite Σ Quick; LEQ, leucite opposing Estelite Σ Quick; ZFT, zirconia opposing Filtek Supreme Ultra; DFT, lithium disilicate opposing Filtek Supreme Ultra; LFT, leucite opposing Filtek Supreme Ultra. I, Intact area; A, Abraded area.

Figure 8

Representative SEM images of composite resin surfaces: ZMG, zirconia opposing MI Gracefil; DMG, lithium disilicate opposing MI Gracefil; LMG, leucite opposing MI Gracefil; ZGD, zirconia opposing Gradia Direct P; DGD, lithium disilicate opposing Gradia Direct P; LGD, leucite opposing Gradia Direct P; ZEQ, zirconia opposing Estelite Σ Quick; DEQ, lithium disilicate opposing Estelite Σ Quick; LEQ, leucite opposing Estelite Σ Quick; ZFT, zirconia opposing Filtek Supreme Ultra; DFT, lithium disilicate opposing Filtek Supreme Ultra; LFT, leucite opposing Filtek Supreme Ultra. I, Intact area; A, Abraded area.