Effect of different laser treatments on the shear bond strength of zirconia ceramic to resin cement

Abstract

Background: Several techniques such as sand blast, silicoating, and laser irradiation have been
introduced for reliable bond between zirconia and resin cement. This study aimed to assess and
compare the effect of three types of lasers on the shear bond strength (SBS) of zirconia to resin
cement.
Materials and Methods: In this in vitro study, 55 zirconia disks (6 mm diameter × 3 mm thickness)
were randomly divided into five groups: control (1), sandblast (2), carbon dioxide (CO2) (3),
erbium‑doped yttrium aluminum garnet (Er: YAG) (4), and neodymium‑doped yttrium aluminum
garnet (Nd: YAG) (5) laser irradiation. The surface morphology of one specimen from each group
was evaluated by a scanning electron microscope. Zirconia disks were cemented to composite
using Panavia F2. SBS test was performed at a crosshead speed of 1 mm/min after 24 h storage in
distilled water and thermocycling. The data were analyzed by one‑way analysis of variance and post
hoc Tukey’s HSD tests (α = 0.05).
Results: The mean SBS values of the groups such as sandblast, Er: YAG, Nd: YAG, and CO2 lasers
and control were 6.64 MPa, 6.63 MPa, 4.98 MPa, 4.39 MPa, and 2.32 MPa, respectively. No significant
difference was observed between sandblast and Er: YAG laser and between Nd: YAG and CO2 lasers.
Conclusion: All lasers increased SBS values of zirconia to resin cement in comparison to the
untreated surface. Er: YAG laser was the most effective laser treatment on the bond strength equal
to that of sandblast.
Key Words: Lasers, resin cements, shear strength, zirconium oxide