# Comparative Evaluation of the Translucency of Polyetheretherketone (PEEK) Veneered With Two Different Materials: An In Vitro Study

## TL;DR

This study compares how well two materials, lithium disilicate and composite resin, improve the translucency of PEEK for dental restorations.

## Contribution

The study provides a direct empirical comparison of translucency and masking ability of two veneering materials on PEEK in dental applications.

## Key findings

- Lithium disilicate veneered PEEK showed significantly higher translucency (TP) than composite resin.
- Lithium disilicate also demonstrated greater masking ability (CR) compared to composite resin.

## Abstract

Introduction: Modern dentistry seeks materials with enhanced aesthetics and properties for restorations. While polyetheretherketone (PEEK) is promising, its low translucency necessitates veneering for visible areas. Lithium disilicate glass-ceramic and composite resins are common veneering options. This in vitro study aimed to comparatively evaluate the translucency of PEEK when veneered with lithium disilicate glass-ceramic and composite resin. This is crucial for achieving predictable aesthetic outcomes.

Methods: 20 sandblasted PEEK specimens (10mm x 10mm, 0.6mm thick) were divided into two groups (n=10). Group A (lithium disilicate) comprised 0.5mm thick A2 shade lithium disilicate veneers, fabricated via lost wax pressing, which were etched, silanized, and luted to PEEK cores with translucent light-cure resin cement. In Group B (composite resin), PEEK discs received an opaquer, then 0.5mm thick A2 shade composite resin was injected into a mold to form the bi-layered specimen. The translucency parameter (TP) and contrast ratio (CR) of the veneered specimens were assessed using a UV-Vis-NIR spectrophotometer. Data normality was confirmed via the Shapiro-Wilk test. Independent samples t-tests were then performed to evaluate inter-group differences, with statistical significance set at p < 0.05.

Results: Statistically significant differences were found between the materials regarding translucency and masking ability (p<0.001 for both TP and CR). Lithium disilicate veneered PEEK (Group A) showed a significantly higher mean TP of 11.42±0.55 (95% CI: 11.03-11.82), indicating superior light transmission. In comparison, composite resin (Group B) had a mean TP of 10.42±0.29 (95% CI: 10.21-10.63). Furthermore, lithium disilicate displayed a statistically higher mean CR of 1.360±0.01 (95% CI: 1.35-1.37), suggesting greater masking ability, compared to the composite resin CR of 1.320±0.01 (95% CI: 1.31-1.33).

Conclusion: Lithium disilicate glass-ceramic, as a veneering material for PEEK, offers a statistically significant advantage in both simulating natural enamel’s translucency and providing better masking. This makes it a more suitable choice for highly aesthetic PEEK-based restorations in demanding zones.