Veneering Thickness Effect on the Optical Properties of Peek Restorations (In Vitro Study)

Abstract

INTRODUCTION: Polyetheretherketone (PEEK) can be used as a core material for fixed prosthodontics. However, information about the optimum veneer thickness of veneered PEEK restorations is still scarce. OBJECTIVES: To evaluate the effect of different composite veneer thickness on the optical properties of PEEK restorations. MATERIALS AND METHODS: Twenty four (n=24) PEEK (BioHPP granules) core disc-shape specimens of 15 mm diameter and 0.8 mm thickness were fabricated and veneered with composite resin (crea-lign, shade A3). The specimens were divided into three groups according to the veneering thickness: core/veneer thickness (mm) of 0.8/1.0, 0.8/1.5, and 0.8/2.0 for groups I, II, and III, respectively. The clinical spectrophotometer (VITA Easyshade) was used for color comparison with the reference color data of the selected shade stored in the device. Statistical analysis was performed with one-way analysis of variance (ANOVA) and student (Unpaired-sample) "t" test. RESULTS: The veneering thickness significantly influenced the ΔE values (p < 0.001). The mean color difference (ΔE) values for groups I, II and III were found to be 8.22(±0.41), 5.13(±0.43) and 3.23(±0.34), respectively. CONCLUSIONS: Color of PEEK restorations was significantly affected by the veneer thickness. The veneer thickness of 2.0 mm showed the best color match with perfect masking ability of the underling PEEK core(ΔE<3.3). In contrast, the veneer thickness of 1.0 and 1.5 mm showed a poor color match with poor masking ability of the underling PEEK core (ΔE>3.3).

Masking Ability of Bleach Shade Composite Resins in Different Thicknesses

“…Color matching in composite resin restorations is not an easy task, especially in cases of severe tooth discoloration and in through and through restorations, as in these situations there is not enough or normal adjacent tooth structure and usually a grayish appearance will be seen in the final composite restoration, which fails color matching [ 5 ]. Complete masking of tooth discoloration through direct restorations is a complex procedure due to the translucency of the composite resins [ 6 – 8 ] and requires careful diagnosis, treatment planning, and the use of the correct restorative technique to reach the acceptable outcomes [ 9 ].…”

Comparison of shear bond strength and color reproduction of two different high-performance polymers veneered with two different thicknesses of resin composite: an in-vitro study

“…In the current study, samples veneered with 0.5 mm resin composite had statistically higher values than 1mm thick samples. Such a result was supported by the El-Sawaf et al [22] study that showed that increasing the thickness of composite veneer will reduce the ΔE values significantly. It was then concluded that a 0.5 mm thickness of a composite veneer layer is considered unacceptable because it allows for a significant increase in light transmission with a significant decrease of masking ability.…”

“…If the ΔE is greater than 1 and less than 3.3, it's considered to be detectable by a skilled operator, but clinically accepted. But if the ΔE is greater than 3.3, it's regarded to be unacceptable because it could be detected by untrained observers [22].…”