Self-adhesive composites are bonded to the tooth without a separate adhesive. Today, independent information regarding their adhesive properties is still limited. Objectives: To investigate the effect of surface smear on the micro-tensile bond strength (µTBS) to dentin. Methods: Self-adhesive flowable composites or adhesive/flowable composite combinations were applied to either bur-cut (medium-grit = 100 µm) or SiC-paper ground (600-grit) dentin surfaces. After 1-week water storage, 5 teeth per group were sectioned into 1x1 mm micro-specimens, prior to being subjected to a µTBS test protocol.
Results:
| Dentin preparation | µTBS | Failure Analysis (%) | ||||||
MPa±SD | ptf/n | S | I | B | B/C | C | |||
Self-adhesive flowable composite | Fusio Liquid Dentin (Pentron Clinical) | bur | 17.7±8.7a,d | 0/30 | 1 | 88 |
|
| 11 |
SiC | 17.1±9.5d | 0/30 |
| 98 |
|
| 2 | ||
Vertise Flow (Kerr) | bur | 5.4±1.7f | 16/24 |
| 94 |
|
| 6 | |
SiC | 9.7±6.2f | 14/31 |
| 38 |
|
| 62 | ||
1-step adhesive/ flowable composite | Adper Prompt L-Pop/ Filtek Supreme XT Flow (3M ESPE) | bur | 25.4±10a,b | 0/30 |
| 3 | 41 |
| 55 |
SiC | 34.9±13.4c | 0/30 | 6 | 16 | 31 | 1 | 47 | ||
AdheSE One/ Tetric Evoflow (Ivoclar Vivadent) | bur | 9.0±5.2f | 3/26 | 2 |
| 85 | 9 | 4 | |
iBond/Venus Flow (Heraeus Kulzer) | bur | 24.7±9.5b,d | 1/31 | 4 | 29 |
| 33 | 34 | |
Xeno V/ X Flow (Dentsply) | bur | 29.4±11.7b,c | 0/30 | 7 | 2 |
| 2 | 90 | |
3-step adhesive/ flowable composite | Optibond FL/ Premise Flowable (Kerr)
| bur | 44.8±13.6e | 0/20 | 33 | 8 | 8 | 5 | 48 |
SD: standard deviation; ptf/n=pre-testing failures/number of specimens; Means with the same superscript are not significantly different (Tukey HSD, p<0.05); ptf=0 MPa; S= substrate; I=interface; B=bond; C=composite
Conclusion: Disregarding one 1-step adhesive/flowable composite combination, both self-adhesive flowable composites exhibited a significantly lower bond strength than the flowable composites that were bonded using a separate adhesive. The way dentin was prepared did not affect the bonding effectiveness of the self-adhesive composites. The more fluid self-adhesive composite Fusio Dentin Liquid bonded significantly better than Vertise Flow.