J Contemp Dent Pract. 2026 Feb 1;27(2):105-116. doi: 10.5005/jp-journals-10024-4020.
ABSTRACT
AIM: The purpose of this study was to assess the clinical performance of recently introduced multilayered ultra-translucent zirconia as a laminate veneer material lithium disilicate laminate veneers in terms of modified United States Public Health Service (USPHS) criteria for assessing dental restorations.
MATERIALS AND METHODS: The minimum estimated sample size was 21 veneers. The sample size was increased to 26 veneers (13 veneers per group) to compensate for a dropout rate of 25%. Healthy patients with normal occlusion and with no parafunctional habits, severe discoloration or rotation, and having sufficient sound enamel thickness, who met the inclusion criteria, were randomly assigned to two groups. In the intervention group, 16 laminates were fabricated from ultra-translucent multilayered (UTML) zirconia. In the control group, 16 laminates were fabricated from lithium disilicate. All preparations were confined to the enamel with chamfer finish line and butt-joint incisal margins. Zirconia veneers were sandblasted and surface-treated with zirconia primer. Acid-etched lithium disilicate veneers were surface-treated with ceramic primer. Both groups were adhesively cemented to the tooth structure with light-cured resin cement. Veneers were assessed immediately after cementation and at 3, 6, 12, and 18 months. United States Public Health Service criteria were used to evaluate each veneer, where retention was specified as the primary outcome. The secondary outcome was the restoration of integrity. The third outcome was color match, and marginal adaptation of the restoration was determined to be the fourth outcome. Data were recorded and statistically analyzed.
RESULTS: Results of multiple follow-ups over 18 months were analyzed using Fisher’s exact test for statistical comparison and showed no statistically significant difference between the two groups. Results of retention at baseline showed that both groups had identical 100% Alpha scores. At 3 months, the lithium disilicate group maintained consistent Alpha scores (100%), while UTML zirconia showed a slight decrease with 93.7% Alpha and 6.3% Bravo scores, with no significant difference between groups (p = 0.31). At 6 months, the lithium disilicate group maintained consistent Alpha scores (100%), while UTML zirconia declined to 81.3% Alpha and 18.7% Bravo scores with an insignificant difference between groups (p = 0.069). Finally, after 12 and 18 months, both groups had identical 100% Alpha scores. Regarding restoration integrity, color matching, and marginal adaptation, both groups recorded Alpha scores throughout the entire follow-up intervals.
CONCLUSION: Although the lithium disilicate group showed better retention results, no significant difference was found in retention, color stability, restoration integrity, and marginal adaptation between the groups.
CLINICAL SIGNIFICANCE: This trial provides evidence-based guidance for selecting materials for conservative restorations. It investigates a new, potentially stronger material for esthetic cases by assessing its clinical performance as a veneer.
TRIAL REGISTRATION NUMBER: https://www.
CLINICALTRIALS: gov. Protocol Registration and Results System, NCT04598737 (22/10/2020). How to cite this article: Elkady MA, Taymour MA, Anwar EM. Clinical Assessment of Teeth Restored with Ultra-translucent Multilayered Zirconia vs Lithium Disilicate Laminates-18-month Follow-up: A Randomized Controlled Trial. J Contemp Dent Pract 2026;27(2):105-116.
PMID:42145158 | DOI:10.5005/jp-journals-10024-4020
