• Tool Sriamporn D.D.S., Ph.D.
• Chutima Kositpantavong D.D.S., M.Sc.
• Niyom Thamrongananskul D.D.S., Ph.D.

Objective To investigate the effect of Dycal on shear bond strengths of four luting resins.

Materials and methods One hundred twenty extracted human permanent molars were ground to
flat dentin surface and were then randomly divided into three groups with forty teeth each. Group 1:
dentin surfaces were not covered with Dycal (control group). Group 2 and 3: dentin surfaces were
covered with Dycal for 7 and 28 days, respectively. Each group was divided into 4 subgroups based on
luting resins (Variolink N, Panavia F 2.0, RelyX U200 and MaxCem Elite). After reaching the cover
time, Dycal was removed and dentin was cleaned. The resin composite rods were bonded on each
group with different resin cements. All specimens were kept in distilled water at 37°C for 24 hours and
they were then subjected to shear bond strength test using a universal testing machine at crosshead
speed 0.5 mm/minute. The data were statistically analyzed by Two-way analysis of variance (ANOVA)
and the Tukeyûs multiple comparison tests at a 95% confidence level. The failure mode was evaluated
under a stereomicroscope and a scanning electron microscope.

Results The shear bond strength for all groups of Variolink N and Panavia F 2.0 showed no
statistically significant difference. All specimens in groups of Variolink N and Panavia F 2.0 exhibited
mix failure. For the groups of RelyX U200 and MaxCem Elite, the shear bond strengths of Dycal
covering dentin for 7-day or 28-day group were significantly lower than control group. The shear
bond strength of Dycal covering dentin for 7-day group and 28-day group demonstrated no statistically
significant difference. All specimens in the groups of RelyX U200 and MaxCem Elite exhibited
adhesive failure. When considering on Dycal treated dentin groups, the shear bond strength in group of
RelyX U200 and MaxCem Elite were significantly lower than groups of Variolink N and Panavia F 2.0.

Conclusion Dycal affects bond strength of RelyX U200 or MaxCem Elite resin cements to dentin but
does not affect bond strength of Variolink N or Panavia F 2.0 resin cements.

(CU Dent J. 2015;38:141-154)