THE EFFECT OF IMPLANT ANGLE AND TI-BASE ABUTMENT HEIGHT ON MONOLITHIC ZIRCONIA CROWN RETENTION

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Kendirli C. E., Güngör H., Kılıçarslan M. A., Karaağaçlıoğlu L.

Meandros Medical And Dental Journal, cilt.27, sa.2, ss.210-218, 2026 (ESCI, TRDizin)

Özet

Objective: This study aimed to evaluate how different Ti-base abutment heights (3.5 mm and 5.5 mm) affect the retention of monolithic zirconia crowns placed on straight (0°) and angled (15°) implants. Material and methods: Sixty monolithic zirconia crowns were fabricated and assigned to four groups according to implant angle and Ti-base height. After CAD/CAM fabrication and standardized cementation, all specimens underwent a pull-out test using a universal testing machine, and maximum force at cement failure (N) was recorded. Due to variance heterogeneity, Welch ANOVA and Tamhane T2 post-hoc tests were used for analysis. Results: Welch one-way ANOVA revealed a statistically significant difference in maximum load among the four experimental models (Welch F(3, 29.49) = 86.08, p < 0.0001). Tamhane T2 post-hoc analysis showed significant differences between all group pairs (p < 0.05), except between Model 1 (0°, 3.5 mm) and Model 3 (15°, 3.5 mm) (p = 0.862). The highest mean maximum load was observed in Model 4 (15°, 5.5 mm) (969.66 N), followed by Model 2 (0°, 5.5 mm) (736.24 N), while the lowest value was recorded in Model 3 (15°, 3.5 mm) (267.10 N). Overall, specimens restored with 5.5-mm Ti-bases demonstrated approximately a three- fold higher maximum load compared with those restored with 3.5-mm Ti-bases. Conclusions: Implant angulation did not affect maximum load capacity in groups with 3.5-mm Ti-base abutments but produced a significant difference between groups with 5.5-mm Ti-base abutments. Overall, increasing Ti-base height significantly enhanced the maximum load capacity for crown retention. Clinically, using the longest appropriate Ti-base height may reduce the risk of crown detachment, especially in angled implant cases.