RETENTION AND MARGINAL INTEGRITY OF CAD/CAM FABRICATED CROWNS ADHESIVELY CEMENTED TO TITANIUM BASE ABUTMENTS--INFLUENCE OF BONDING SYSTEM AND RESTORATIVE MATERIAL.

Purpose: To assess the influence of the bonding system and restora5ve material on the marginal integrity and pull-off forces of monolithic all-ceramic crowns bonded to 5tanium base (5-base) abutments. Materials and Methods: A total of 108 5-bases were sandblasted and divided into nine experimental groups (n = 12) according to the combina5on of crown material (polymer-infiltrated ceramic-network [PI], lithium-disilicate [LD], and zirconia [ZI]) and bonding system (Mul5link Hybrid-Abutment [MH], Panavia V5 [PV], RelyX Ul5mate [RU]) with the respec5ve primers. AXer bonding the crowns to the 5-base abutments, the restora5ons were screw-retained on implants and thermomechanically aged (1,200,000 cycles, 49 N, 1.67 Hz, 5 to 55°C). Marginal integrity and bonding failures were evaluated under a light microscope, and pull-off forces (N) were calculated. Chi-square tests for marginal integrity as well as one-way and two-way ANOVA sta5s5cal tests for pull-off forces were applied (α = .05). Results: PI presented higher marginal integrity than LD (P = .023). Bonding system PV revealed higher marginal integrity than MH (P =.005) and RU (P =.029). Differences in pull-off forces were found between restora5ve material and resin cements (P < .001), with the highest values for ZI + RU (598 ± 192 N), PI + PV (545 ± 114 N), LD + MH (532 ± 116 N), and PI + RU (528 ± 81 N). Specimens with marginal integrity revealed higher pull-off forces than those with altera5on (P = .006). Specimens presen5ng bonding failures (micromovements) showed lower pull-off forces than those without bonding failures (P < .001). Conclusions: The tested CAD/CAM materials show favorable bonding performances with different bonding systems, nevertheless for each restora5ve material a specific bonding system has to be recommended. [ABSTRACT FROM AUTHOR]