Effect of the screw-retained abutment material on the fatigue behavior of lithium disilicate restorations

TL;DR

This study found that zirconia abutments improve the durability of lithium disilicate dental restorations under stress compared to other materials.

Contribution

The study introduces a comparison of abutment materials' effects on lithium disilicate restorations under fatigue conditions.

Findings

Zirconia abutments showed the highest fatigue failure load compared to other materials.

PEEK abutments had the lowest fatigue failure load, indicating poorer performance.

SEM and finite element analyses confirmed the influence of abutment material on stress distribution.

Abstract

The aim of the study was to evaluate the effect of the screw-retained abutment material (zirconia (Yz), lithium disilicate (Ld), Polymer-infiltrated ceramic network (Picn), and Polietheretherketone (Peek)) on the fatigue behavior and stress distribution of lithium disilicate restorative material. Ld discs (Ø= 10 mm; thickness = 1 mm) were obtained and allocated into four groups according to the abutment material factor: Yz, Ld, Picn, and Peek (Ø= 10mm; thickness 3 mm). A screw access hole was made at the center of each abutment and filled with resin composite (thickness = 2 mm). The materials were adhesively bonded and tested under monotonic mechanical load (n= 3) and cyclic fatigue (n= 15; initial load: 200 N for 10,000 cycles; step size: 100 N/10,000 cycles; frequency: 20 Hz) until failure. Finite element and Scanning Electron Microscopy (SEM) analyses were also performed. The obtained data were analyzed by 1-Way ANOVA for monotonic (α=0.05) and Kaplan Meier and log-rank post-hoc for fatigue data tests. All groups presented a decrease in the fatigue failure load (FFL) when compared to the monotonic test. The abutment material affected the lithium disilicate restoration performance (p=.048; F= 4.134), since zirconia showed the highest FFL (p<.05), followed by Picn and Ld, which were similar to each other (p>.05). The lowest values of FFL were found for Peek (p<.05). The screw-retained abutment material influences the fatigue behavior of lithium disilicate restorations, being zirconia the most indicated material to enhance mechanical performance.

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