Microtensile bond strength of a filled vs unfilled adhesive to dentin ...

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Table 3 Mean microtensile bond strength to dentin using One-Step Plus and One-Step adhesives with total and
self-etch technique.
Type of adhesive Technique MeanGsd
Filled (One-Step Plus) Total-etch 38.8G12.2 a (nZ20)
Filled (One-Step Plus) Self-etch 22.4G4 b (nZ20)
Unfilled (One-Step) Total-etch 33.9G8.5 a (nZ20)
Unfilled (One-Step) Self-etch 26.4G7.5 b (nZ20)
Different superscript letters indicate significant differences by two-way ANOVA and post hoc Tukey’s test (p!0.05).
Japan) and polished using wet silicon carbide
abrasive papers and diamond pastes of decreasing
abrasiveness to 0,25 mm (DP-Paste, P, Streuers
A/S, Copenhagen, Denmark). They were then
subjected to argon ion etching (EIS-1E, Elionix
Ltd, Tokyo, Japan) for 5 min with a constant
voltage of 1 kV and ion current density of
0.2 mA/cm 2 , with the ion beam directed 908 to
the specimen surface, 22 gold-sputter coated and
observed using a scanning electron microscope
(JSM 5400; JEOL Ltd, Tokyo, Japan).
Four additional non-carious third molars (one
per group) were used for SEM examination of the
resin-dentin interfaces to serial acid-base treatment
resistance. The specimens were prepared as
in the above mentioned manner and polished.
They were then subjected to 10% phosphoric acid
treatment for 3–5 s 23 followed by 5% sodium
hypochloride immersion for 5 min. 24 After being
extensively rinsed, the specimens were dried
gold-sputter coated and observed using a scanning
electron microscope (JSM 6335F; JEOL Ltd,
Tokyo, Japan).
Results
Two-way ANOVA showed that the mTBS results
(Table 3) were significantly influenced by the
technique (pZ0.000) but not by the type of
adhesive (pZ0.836). The interaction of these two
factors was significant (pZ0.025), indicating that
the differences that existed between two techniques
(total-etch and self-etch) were not dependent
on the type of adhesive.
Multiple comparisons (post hoc Tukey’s test)
revealed that total-etch technique exhibited significantly
higher bond strength values than the selfetch
technique with both filled (pZ0.000) and
unfilled adhesives (pZ0.031). The mTBS of the filled
adhesive One-Step Plus (38.8G12.2 MPa) and the
unfilled adhesive One-Step (33.9G8.5 MPa) were
not significantly different when they were used with
the total etch (pZ0.298), and with the self-etch
E. Can Say et al.
technique (22.4G4.0 and 26.4G7.5 MPa, respectively)
(pZ0.459).
SEM observations of the resin-dentin interfaces
revealed that the thickness of the hybrid layers
Figure 1 (A) Scanning electron micrograph of the resin–
dentin interface bonded with One-Step Plus with totaletch
technique after argon ion etching. Hybrid layer was
3 mm thick. Fillers were uniformly dispersed in the
adhesive layer and were evident around the tubuler
orifices and in the tubules (arrow). c, composite; fa, filled
adhesive; h, hybrid layer; d, dentin. (B) Scanning electron
micrograph of the resin–dentin interface bonded with
One-Step Plus with total-etch technique subjected to
sequential acid–base treatment. Hybrid layer was
approximately 3 mm thick and resin-tags (arrow) penetrating
into dentinal tubules were clearly observed.
Adhesive layer was 17 mm thick. c, composite; fa, filled
adhesive; h, hybrid layer; d, dentin.