The Influence of Different Dental Implant Abutment Materials on the Color of Lithium Disilicate Crowns: A Combined In Vitro and Clinical Study

Dental implants in the anterior region represent a reliable and esthetically pleasing alternative to traditional bridges. Titanium abutments are considered the gold standard in implant dentistry; however, their use in esthetic zones often results in gray discoloration, particularly when combined with all-ceramic restorations or in patients with thin peri-implant tissues. Zirconia abutments have been proposed as an alternative to overcome these limitations. This study aimed to evaluate the effect of different abutment materials on the color change of lithium disilicate crowns through both in vitro and clinical assessment.

Thirty lithium disilicate crowns (IPS e.max CAD) of standardized central incisor form were fabricated and distributed equally among three groups: (1) titanium abutments, (2) zirconia abutments with a titanium base, and (3) titanium abutments coated with opaque material. Crowns were placed on the respective abutments with glycerin as an intermediate medium, and color change was measured using the Easy Shade device. Data were analyzed with the Kruskal-Wallis test due to non-normal distribution.

Significant differences were observed among the groups. Lithium disilicate crowns supported by titanium abutments demonstrated clinically unacceptable color changes (ΔE = 9.7). Zirconia abutments with a titanium base produced color changes closely resembling natural dentition (ΔE = 6.1), while opaque-coated titanium abutments yielded clinically acceptable results (ΔE = 7.8).

The results indicate that the abutment material significantly influences the final color of lithium disilicate crowns. Zirconia abutments effectively mask the underlying metallic hue due to their high radiopacity and light-scattering properties, while opaque coating provides a viable and more affordable alternative to mitigate the graying effect of titanium abutments.

Within the study limitations, zirconia abutments with titanium bases and opaque-coated titanium abutments are recommended over conventional titanium abutments in the anterior region to achieve superior esthetic outcomes with lithium disilicate crowns.

This study is registered with the Research Registry under the identifying number: researchregistry11472, and the reference hyperlink is: https://www.researchregistry.com/browse-the-registry#home/