Bonding and conditioning of the prepared tooth are always necessary prior to cementation of indirect restorations with resin cements. A self-adhesive resin cement has been developed, not requiring any conditioning of the tooth. Purpose: This study compared the bond strength of a self-adhesive cement Unicem (UN, 3M ESPE) with two resin cements Calibra (C, Dentsply/Caulk) and Variolink (V, Ivoclar/Vivadent), to enamel and dentin, using light-cured and self-cured modes. Materials and Methods: Cements were applied on human enamel and dentin in a thin layer and light cured for 40 sec or, when self-cured, they were applied in a single layer and allowed to set. Specimens were stored in water at 37 ˚C for 24 hours and debonded in tension at 0.5 mm/min using a testing machine. Results: Means and standard deviations of bond strengths are listed.
|
Cement/ Mode of Cure |
Bond Strength, MPa Enamel Dentin |
|||
|
|
LC |
SC |
LC |
SC |
|
UN |
7.0 (6.1) |
13.5 (4.1) |
14.6 (8.9) |
9.0 (5.5) |
|
C |
24.4 (6.5) |
22.9 (3.8 ) |
24.6 (4.9) |
3.7 (0.9) |
|
V |
25.6 (6.4) |
27.9 (7.2) |
19.4 (5.2) |
26.4 (5.5) |
Data were analyzed by ANOVA. Fisher’s PLSD intervals (p=0.05) were 2.4, 2.9 and 2.4 MPa for tooth substrate, cement and curing mode, respectively. There were significant statistical differences in bond strength among dental substrates, resin cements and curing modes. Bond strengths of UN to enamel were higher for SC than LC but to dentin were higher for LC than SC. Conclusions: Overall, the self-adhesive cement showed lower bond strengths to dental substrates in both curing modes, compared to C and V resin cements. Supported by 3M ESPE.