Bonding glass-ceramic to human dentin: influence of immediate sealing and provisional cements

This in vitro study investigated the effect of immediate dentin sealing and provisional cements on the microtensile bond strength of resin-bonded glass-ceramic to dentin.

Occlusal surfaces of 60 maxillary premolars were cut perpendicular to the long axis of the teeth to expose dentin. A total of 60 pressable lithium disilicate glass-ceramic specimens (e.max Press, Ivoclar) were fabricated in the laboratory. Prepared teeth were classified into six groups according to dentin conditioning as follows: Group 1, freshly cut dentin (control group; C); Group 2, immediate dentin sealing (IDS); Group 3, immediate dentin sealing plus resin-based provisional cement (IDS-RC; Provitemp, Itena Clinical); Group 4, immediate dentin sealing plus conventional provisional cement (IDS-CC; NETC, Meta Biomed); Group 5, dentin without sealing plus resin-based provisional cement (C-RC); and Group 6, dentin without sealing plus conventional provisional cement (C-CC). Universal adhesive (Tetric N-Bond Universal, Ivoclar) was used for IDS, and provisional restorations were temporarily inserted to prepared teeth using provisional cements. Test groups (IDS-CC, IDS-RC, C-CC, and C-RC) were covered with provisional restorations and kept in a water bath for 2 weeks. Intaglio surfaces of ceramic specimens were etched using 9.5% hydrofluoric acid for 15 seconds then rinsed with water and ultrasonically cleaned for 3 minutes in 99% alcohol and air dried. Universal primer (Monobond N, Ivoclar) was applied immediately to the etched intaglio surfaces. Self-adhesive resin cement (Multilink Speed, Ivoclar) was mixed and applied to the intaglio surfaces of ceramic restorations. Ceramic restorations were bonded to conditioned teeth, and excess cement was removed. All specimens were light-polymerized for 20 seconds from four directions. Bonded specimens were artificially aged as follows; 1 hour after bonding, specimens of all test groups were stored in a water bath at 37°C for 5 months followed by thermal cycling for 5,000 thermal cycles to simulate clinical conditions. The microtensile bond strengths were recorded in MPa. Tukey HSD test (P ≤ .05) was used for statistical analysis.

Compared to the control group (C) (6.37 ± 3.26 MPa), immediate dentin sealing significantly increased microtensile bond strength (P .05) for the following groups: IDS (13.76 ± 7.72 MPa), IDS-RC (15.24 ± 5.60 MPa), and IDS-CC (13.99 ± 6.98 MPa). However, provisional cementation did not significantly affect microtensile bond strength for groups C-RC (5.08 ± 2.91 MPa) and C-CC (4.45 ± 1.92 MPa) (P >.05).

Immediate dentin sealing had a significant impact on resin bonding to lithium disilicate glass-ceramic.