Research Information System
PROCEEDINGS (MDPI), vol.18, no.2, pp.1-14, 2026 (Peer-Reviewed Journal)
This in vitro study evaluated the shear bond strength (SBS) of four CAD/CAM (Computer
aided design/Computer aided manufacturing) polymer-based indirect composites bonded
to dentin and microhybrid composite substrates using two resin cements. Gradia Plus
(GP), Ceramage (Ce), Tescera ATL (TA), and Lava Ultimate (LA) were fabricated into
cylindrical specimens (3 × 3 mm). Dentin substrates were obtained from extracted molars,
while composite substrates were prepared from Filtek Z250 (4 mm × 2 mm). Bonding was
performed using either a self-adhesive resin cement (RelyX U200; RU200) or a dual-cure
adhesive resin cement (RelyX Ultimate; RU), resulting in 16 experimental groups (n = 12
per group). SBS was measured using a universal testing machine (1 mm/min), and failure
modes were assessed under stereomicroscopy. Bond strength was significantly higher
on composite substrates than on dentin (p < 0.001), primarily due to favorable polymer–
polymer compatibility and matrix interdiffusion, which improved stress accommodation
at the adhesive interface. TA and Ce showed superior adhesion when combined with RU,
while LA exhibited the lowest values, particularly on dentin bonded with RU200. Overall,
the dual-cure adhesive system provided stronger bonding than the self-adhesive system
(p < 0.05). These findings highlight the influence of substrate type, composite architecture,
and cement chemistry on interfacial performance in indirect polymer-based restorations.