Objectives: To evaluate the performance of repairs of restorative materials using different materials.
Methods: Different restorative materials were analysed: 1) nanohybrid composite (Tetric EvoCeram), 2) nanocomposite (Filtek supreme XT), 3) silorane (Filtek silorane), 4) compomer (Dyract eXtra) and 5) ormocer (Admira), artificially aged and stored for 2.5 months. The specimens were air abraded, silanated and divided in two subgroubs. In subgroup A, the homologue material with the corresponding adhesive was used for reparation procedure. In subgroup B, all samples were treated with the same adhesive and composite (Optibond FL, Tetric EvoCeram). The specimens were thermomechanically aged and microtensile bond-strength (MTBS) was measured (n=30). Fracture analysis was performed with stereomicroscope. Statistical differences between groups were evaluated with Wilcoxon rangsum test and Bonferroni adjustment (a=0.05).
Results:
Table: MTBS in MPa (standard-deviation) and failure analysis.
group
| MTBS (±SD)
| p-value
| Failure type
| ||
adhesive
| cohesive
| mixed
| |||
1A
| 41.1±8.2a | 0.6543
| 2
| 28
| 0
|
1B
| 41.1±13.2A,B,C,D,E | 4
| 26
| 0
| |
2A
| 37.4±9.7a | *0.0055
| 24
| 6
| 0
|
2B
| 44.8±10.2A,B,C,E | 1
| 28
| 1
| |
3A
| 36.6±13.2a | *0.0034
| 28
| 2
| 0
|
3B
| 45.1±7.4C, E | 4
| 25
| 1
| |
4A
| 60.9±7.8b | *<0.0001
| 4
| 26
| 0
|
4B
| 36.0±8.9D | 4
| 26
| 0
| |
5A
| 52.5±9.3c | *0.0176
| 8
| 20
| 2
|
5B
| 45.8±10.8E | 4
| 26
| 0
| |
Same superscripts indicate no significant differences. The * indicates significant differences between A and B.
All groups showed significant differences in MTBS regarding subgroups A and B, except for group 1. For groups 2 and 3, MTBS was significantly higher with procedure B, whereas in groups 4 and 5 significantly lower values were measured with procedure B. The most frequent fracture type was 'cohesive', except for 2A and 3A, where adhesive failure was predominant.
Conclusions: Repairing procedures with homologue or heterologue material showed significant differences in MTBS. However, cohesive failures indicated that the repairing procedure was in most cases successful at the interface.