Objective: To measure shear bond strength when bonding new composite to aged composite with and without interfacial resins and surface treatments.
Methods: Disks (dia 5mmx2.5mm) of three composites1-3 were fabricated using a PTFE mould and placed in water at 23˚C. After 0, 28 and 90 days 60 specimens of each material were removed, divided into 6 groups (n=10), and treated as follows prior to adding a second increment of composite: Group (1) No treatment (2) layer of Prime & Bond (P&B) 4, (3) layer of Optibond Solo plus(OS+)5 (4) abrasion with pumice (5) abrasion + P&B (6) abrasion +OS+. The specimens were mounted in PMMA and fixed in a Universal Testing Machine (Nene Ltd). The specimens were fractured in shear mode (crosshead speed 0.5mm sec-1).Differences were determined using Multivariate ANOVA entering Material, Time and Group as the dependant variables
Results:
|
Material |
Time |
No Treat |
P&B |
Opti-Solo |
Abrasion |
Ab + P&B |
Ab + OS+ |
|
Spectrum |
0 day* |
15.7 |
32.2 |
44.5 |
29.2 |
30.6 |
35.2 |
|
|
28 days |
0.0 |
39.0 |
38.5 |
17.3 |
24.1 |
22.1 |
|
|
90 days |
0.0 |
40.8 |
41.8 |
31.3 |
41.6 |
45.9 |
|
Durafil |
0 day* |
16.3 |
25.0 |
31.7 |
18.2 |
23.9 |
24.4 |
|
|
28 days |
11.3 |
28.4 |
30.4 |
13.3 |
12.6 |
16.3 |
|
|
90 days |
21.2 |
27.9 |
29.4 |
18.1 |
21.8 |
27.7 |
|
Herculite |
0 day* |
16.9 |
40.2 |
43.0 |
15.4 |
25.6 |
30.8 |
|
|
28 days |
0.0 |
33.9 |
38.3 |
0.0 |
31.1 |
33.2 |
|
|
90 day |
0.0 |
33.7 |
33.9 |
0.0 |
38.4 |
33.9 |
Values = mean bond strength (unit= MPa). * first composite treated and new composite bonded immediately
MANOVA analysis Time F=72.9 p<0.001, Material F=28.6 p<0.001 Group F 229.8 p<0.001
Conclusion: The highest shear bond strengths were achieved by using resin bonding agent. With two composites no treatment led to zero bond strength. 1Spectrum, Dentsply UK; 2Durafill VS, Heraeus Kulzer, Germany; 3Herculite XRV, Kerr, Italy; 4Prime&Bond NT, Dentsply, UK; 5Optibond Solo plus, Kerr, Italy