Abstract
AIM: This retrospective study was designed to investigate the 12-month clinical performance of zirconia-lithium disilicate crowns among Yemenis using the modified United States Public Health Service (USPHS) criteria and patient satisfaction via the visual analog scale (VAS). Participants and methodology: This retrospective clinical study analyzed data from eight Yemeni patients who received a total of 103 single full-coverage crowns. All crowns had a zirconia core veneered with lithium disilicate. The crowns were fabricated using CAD/CAM technology and placed on anterior and posterior teeth in both the maxillary and mandibular arches. United States Public Health Service (USPHS) criteria were utilized to assess parameters such as marginal adaptation, color match, and retention. Meanwhile, VAS was used to measure patient satisfaction. Clinical evaluations were recorded at baseline (within one-week post-cementation), 3-, 9-, and 12-month post-cementation. Following data collection, the data were analyzed using the Statistical Package for Social Sciences with Chi-square and McNemar tests.
RESULTS: The survival and success rates were 100% and 97.1%, respectively. Significant degradation occurred in marginal adaptation (11.6% Bravo scores at 12 months) and color match (14.6% Bravo), particularly in posterior teeth and left-side restorations. Non-vital abutments had higher failure, with 2.9% Charlie/Delta scores. Patient satisfaction remained high, with mostly "very satisfied" scores. However, the marginal and color scores declined slightly. Moreover, khat chewing correlated with color changes but lacked statistical significance.
CONCLUSION: The findings of this study highlight that zirconia cores veneered with lithium demonstrated excellent retention and biological performance. However, they exhibited gradual degradation in marginal adaptation, restoration integrity, and color match.
CLINICAL SIGNIFICANCE: Clinicians are advised to weigh the esthetic and durable benefits of zirconia-lithium disilicate crowns against potential marginal degradation and discoloration in patients with high occlusal stress or social habits such as khat chewing. How to cite this article: Al-Hamzi MA, Al-Badani ITH, Al Kbous EHM, et al. Twelve-month Clinical Outcomes of Zirconia Cores Veneered with Lithium Disilicate Crowns: A Retrospective Study. J Contemp Dent Pract 2025;26(6):540-550.