Clin Oral Implants Res. 2026 Apr 20. doi: 10.1111/clr.70130. Online ahead of print.
ABSTRACT
OBJECTIVES: This laboratory study investigated the effect of two different retentive heights of Ti-base abutments (3.5 and 5.5 mm) and crown heights (13 and 16 mm) on the load at failure and survival of monolithic zirconia implant-supported crowns replacing a maxillary central incisor.
MATERIALS AND METHOD: Forty implant-supported crowns were divided into four groups (n = 10 each): short crown/long abutment (SCLA), short crown/short abutment (SCSA), long crown/long abutment (LCLA), and long crown/short abutment (LCSA). Specimens underwent thermal cycling and incremental mechanical cyclic loading starting at 450 N increasing by 50 N until failure. Load and cycles at failure, Weibull analysis, mode of failure, and fractographic assessments were performed.
RESULTS: Mean load at failure was highest for the SCSA group (536.9 N ± 78.4 N), then SCLA (493.4 ± 53.2 N) and LCLA (491.3 ± 40.7 N), and lowest for the LCSA group (453.7 N ± 2.8 N). The differences were statistically significant (p = 0.035). Cycles at failure showed significant differences among groups (p < 0.001), with SCSA demonstrating the greatest cycles at failure (72,492 ± 44,551 cycles), then SCLA (43,630 ± 27,579 cycles) and LCLA (37,706 ± 18,826 cycles), and LCSA the lowest (8399 ± 7308 cycles). Short crowns showed abutment/screw fractures, while longer crowns had more crown fractures.
CONCLUSION: Crown height significantly influenced load at failure and survival, with shorter crowns performing better. The retentive height of the Ti-base abutment had less impact; however, shorter abutments provided better mechanical performance when paired with shorter crowns, suggesting careful consideration for anterior restorations.
PMID:42007538 | DOI:10.1111/clr.70130
