الفهرس 
Introduction.Only 14 pages are availabe for public view
 |  | from | 144 |  |  |
| | | from | 144 | | |
Abstract
Due to the absence of a glassy matrix in zirconia that etching agents may act on, bonding to zirconia is challenging. Surface contamination and the type of surface cleaning method are crucial elements when bonding to zirconia ceramic.
Objective: The aim of this study was to evaluate the effect of two surface contaminants and different cleansing agents on the resin bond strength of partially stabilized zirconia.
Method: 80 Partially stabilized zirconia samples were randomly divided into two groups (n=40) according to the surface contaminant into group (S): saliva, group (D): disclosing agent. Each group will then be subdivided into three subgroups (n=10) according to the surface cleansing method into Subgroup (V): Ivoclean agent, Subgroup (A): airborne particle abrasion and Subgroup (W): water. And there will be a control group; group (SC) and (DC): (surface contamination and no cleaning) (n=20). Sandblasting was done to all zirconia discs surfaces using Al2O3 particles of 50 μm at 10 mm distance for 10 seconds.
80 Airborne particle abraded partially stabilized zirconia specimens were randomly divided into two groups; one group was contaminated with fresh saliva, and the other group was contaminated with disclosing agent. 20 specimens were used as a control group with contamination and no surface cleansing.
Surface cleansing was done as follows:
a- Airborne particle abrasion: contaminated specimens’ surface will be airborne particle abraded with 50 μm Al2O3 particles for 10 s at a pressure of 2.5 bars atom perpendicular to the bonding surface from approximately 10 mm.
b- Ivoclean: contaminated specimens will be cleaned with Ivoclean.
c- Water: contaminated specimens will be cleaned with water spray.
Bonding was done by applying dual-cured self-adhesive resin cement to the treated surfaces in all subgroups according to the manufacturer’s instructions through injection in clear silicone tubes (Ryle’s tube) with an inner diameter of 3mm and an outer diameter of 4mm with length of 3mm.
After that all prepared specimens were thermocycled 5000 cycles (between 5 and 55oC) dwell time 10 seconds. before Shear bond strength testing.
This was followed by measuring the shear bond strength of each group after bonding and thermocycling using a universal testing machine. Followed by an assessment of the mode of failure.
Images showed that adhesive failure in the resin interface was more predominant in contaminated groups with no surface cleaning and in groups where water was used as a cleansing agent while mixed failures were found in groups that used Ivoclean and Airborne particle abrasion being more predominant in the later.