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Document Type

Original Study

Abstract

Objective: This study was designated to evaluate the effect of saliva contamination and cleaning methods on the surface free energy and the shear bond strength of resin cement to zirconia ceramics. Materials and Methods: A total of 80 samples were copy milled (CAD/CAM) from Zirconia blank. The samples were randomly divided into (4) groups (n=20) according to method of cleaning. Group 1 (control): No saliva contamination,Group 2: The samples cleaned with distilled water,Group 3: The samples cleaned with ivoclean, Group4:The samples cleaned with re-sandblasting. Each group was subdivided into 2 subgroups according to the type of adhesive resin cement (Multilink Speed and RelyX Ultimate) used (n=10). Each subgroup was further subdivided into two divisions according to the type of test (surface free energy and bond strength) performed (n=5). One-way analysis of variance ANOVA test and Tukey’ post hoc test were done for comparing variables. Results: The control groups record the lowest mean contact angle value (25.81°±1.76°) and the highest mean surface free energy value (107.57mN/m). While the group washed with water revealed the highest mean contact angle value (39.04°±0.68°) and the lowest mean surface free energy value (98.58 mN/m). Regarding shear bond strength the results showed that the highest shear bond strength value was recorded for the control group (14.33±1.98& 13.73±1.33 MPa), for Multi-link speed and Rely-X ultimate cement respectively , followed by re-sandblasting group, followed by ivoclean group, while the lowest shear bond strength value was recorded for the group washed with water (10.9±0.53& 8.22±0.85 MPa). However, regardless of the cleaning protocol groups, Multi-link speed cement recorded a higher mean shear bond strength value than RelyX Ultimate cement. However these difference was statistically non-significant except for the group washed with water (p=0.0003) as indicated by unpaired t test. Failure modes for all groups were evaluated, failure modes was either adhesive, cohesive or mixed, with frequency ranging from 20 to 40% for each type of failure. The group washed with water showed that allof cases of failure were of the adhesive type in both cement (100%). Conclusion: Cleaning of the contaminated ceramic surface before adhesive cementation is an indispensable step in order to achieve a strong bond. Moreover, the removal of surface contaminants by sandblasting and Ivoclean paste can be considered efficient cleaning methods for zirconia surfaces

Keywords

(CAD/CAM) zirconia ceramics; surface free energy; Shear bond strength

Subject Area

Restorative Dentistry Issue (Removable Prosthodontics, Fixed Prosthodontics, Endodontics, Dental Biomaterials, Operative Dentistry)

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