Shade Stability of Polymer Infiltrated and Resin Nano Ceramic Crowns after Dynamic Chewing Simulation

Abstract

Objective: Investigation of the shade stability of polymer-infiltrated and resin nano ceramic crowns before and after artificial aging.

Method: 40 identical crowns of each of the materials VITA Enamic (VE) and Lava Ultimate (LU) were manufactured. Half of the crowns went through a dynamic chewing simulation (CS) with thermocycling. Material subgroups: 1. VE, 2. VE/CS, 3. LU, 4. LU/CS (each n=20). These were divided into 4 groups (n=5) and distributed in usual stain solutions. The shade of each crown was measured occlusally and vestibularly before and after insertion using a spectrophotometer (n=5). The data were analyzed using ANOVA and Tukey's test (p≤0.05).

Results: Sum scores (SSC) of the occlusal ΔE values: LU/CS: 7.99, VE: 5.75 VE/CS: 5.44, LU: 5.17. The total sum of the SSC yielded, for the materials: SSCtotal(VE): 20.0 and SSCtotal(LU): 24.0.

Significance: Occlusally, there were significant shade differences for VE/CS (p=0.025) and LU/CS (p=0.014) between red wine and distilled water. LU/CS is significantly more clearly stained occlusally by coffee in comparison to the other three material subgroups (VE: p=0.007, LU: p=0.026, VE/CS: p=0.013).

Conclusions: The shade stability of VITA Enamic crowns is superior to that of Lava Ultimate crowns. Only Lava Ultimate is affected by chewing simulation.

Keywords: Accelerated Artificial Aging; Lava Ultimate; Polymer-Infiltrated Ceramic; Resin Nano-Ceramic; Shade Stability; Vita Enamic.