Objectives: The aim of this study was to compare shear bond strengths of five composite resin luting materials (Variolink II [Vivadent], Panavia F-TC [Kuraray], Panavia F-2.0 [Kuraray], RelyX Unicem [3MESPE]), Dyract Cem [DeTrey/Dentsply]) using the recommended adhesive system, and one glass ionomer cement (Ketac Cem [3MESPE]).
Methods: Shear bond strengths to enamel and dentin with and without thermocycling (6000 cycles, 5°/55°C) were determined according to ISO TS 11405. Pairwise comparisons among groups were made using the Mann-Whitney-U-test (p £ 0.05). Median values and 25- and 75% quartiles calculated from 10 replications are shown in the following table:
Results:
|
Enamel |
Dentin |
|||
|
no thermocycling |
thermocycling |
no thermocycling |
thermocycling |
|
|
Variolink II + Syntac Classic |
31.9 (27.2/35.9) |
27.0 (22.2/38.9) |
15.1 (10.7/18.0) |
19.8 (14.7/25.0) |
|
Panavia F-TC + ED Primer |
21.5 (18.2/25.4) |
22.5 (20.3/26.4) |
7.3 (5.9/9.8) |
9.2 (4.6/10.9) |
|
Panavia F-2.0 + ED Primer II |
23.6 (21.1/27.0) |
21.2 (9.3/25.2) |
10.5 (8.8/13.4) |
7.4 (5.2/9.9) |
|
Rely X Unicem (no adhesive system) |
14.5 (10.5/16.9) |
6.6 (5.3/9.8) |
10.8 (9.1/18.4) |
14.9 (10.3/16.4) |
|
Dyract Cem + Prime & Bond NT |
17.6 (15.9/20.4) |
17.0 (11.1/20.1) |
10.1 (5.7/15.0) |
4.5 (1.8/17.2) |
|
Ketac Cem |
6.1 (5.5/6.8) |
1.9 (1,8/2.4) |
4.1 (3.3/5.1) |
4.6 (3.2/6.2) |
Conclusions: Median bond strengths of Variolink II were always equal or higher compared to all other systems under each condition, wheras the glass ionomer cement almost always showed distinctly lower values. Thermocycling caused lower values only in enamel for Rely X Unicem and Ketac Cem. Under equal conditions, bond strengths in enamel were always higher compared to dentin, except with Rely X Unicem and Ketac Cem, where values in dentin were higher compared to enamel after thermocycling. In summary, each of the tested systems showed at least one weak spot with median bond strengths below 10 MPa, with exception of Variolink II, where median values never dropped below 15 MPa under each condition.