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| Title |
Al2O3 Airborne Particle Abrasion of Milled Zirconia Copings for Improvement of Veneering Porcelain Bond Strength Not Currently Well Supported |
| Clinical Question |
For porcelain veneered zirconia crowns, will airborne particle abrasion of a milled zirconia coping with Al2O3 increase the subsequent bond strength of the veneering porcelain?
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| Clinical Bottom Line |
At this time there is insufficient evidence to suggest that surface treatment of a milled zirconia crown coping with Al2O3 airborne particle abrasion will increase the bond strength of veneering porcelains. |
| Best Evidence |
(you may view more info by clicking on the PubMed ID link) |
| PubMed ID |
Author / Year |
Patient Group |
Study type
(level of evidence) |
| #1) 22443122 | Harding/2012 | yttria-stabilized tetragonal zirconia polycrystalline 16 mm disks, 8 per test group | Laboratory study | | Key results | The mean tensile bond strength (MTBS) between veneering porcelain and Zirconia core was significantly decreased in the groups prepared with airborne particle abrasion (p=0.043). | | #2) 22633594 | Teng/2012 | yttria-stabilized tetragonal zirconia polycrystalline cores (5.0 mm width, 5.0 mm long, 10.0 mm high) per test group | Laboratory study | | Key results | The mean shear bond strength (MSBS) between veneering porcelain and Zirconia core was not significantly impacted by airborne particle abrasion. | |
| Evidence Search |
((("Zirconium"[Mesh] AND "Materials Testing"[Mesh]) AND "Dental Bonding"[Mesh]) AND "Dental Veneers"[Mesh]) AND "Ceramics"[Mesh] AND Comparative Study[ptyp] |
Comments on
The Evidence |
Validity:
Both cited studies were in vitro comparative trials implementing similar materials and methods of surface treatment but with different preparation and testing methods. The two did not use the same controls; Harding (2012) used an unmodified Zirconia control, while Teng (2012) used a metal ceramic system. Harding (2012) had a larger sample size that was screened for defects before testing, while Teng (2012) had a smaller sample size that was prepared to stringent standards. Both qualitatively confirmed the results of their stress testing with visual means. Harding (2012) included a wet cyclic loading as part of the study groups to enhance clinical relevance, and Teng (2012) prepared specimens in a way similar to clinical application. Several weaknesses are noted, including possible residual stress in the Harding study (2012) and non-clinical specimen shapes in Teng investigation (2012). Neither study addressed the impact of aging on porcelain bond strengths.
Perspective:
Airborne particle abrasion of metal copings before veneering porcelain application is the industrial standard. That practice has been extended to the surface treatment of zirconia copings with little supporting evidence of the efficacy. The findings of these two in vitro studies suggest the practice to be unnecessary or even inappropriate. There are many surface treatments used for zirconia in anticipation of porcelain veneering, including chemical, laser, and proprietary porcelain bonding agents. The effect of those treatments has proven to be highly variable and somewhat porcelain system specific. The definitive answer to the question of whether airborne particle abrasion is effective for zirconia coping surface preparation for porcelain veneering may be different for each pairing of proprietary zirconia and porcelain products.
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| Applicability |
Since these are in vitro studies, the results are not directly applicable to clinical use. The results are mixed and lack long-term evidence of clinical survivability. They do not suggest which surface treatment would be expected to provide the best clinical result for a patient. |
| Specialty/Discipline |
(General Dentistry) (Prosthodontics) (Restorative Dentistry) |
| Keywords |
Ceramics, zirconia, bond strength, stress test
|
| ID# |
3048 |
| Date of submission: |
03/15/2016 |
| E-mail |
oviatt@livemail.uthscsa.edu |
| Author |
Alyssa-Joy Oviatt |
| Co-author(s) |
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| Co-author(s) e-mail |
|
| Faculty mentor/Co-author |
Stephan Haney, DDS |
| Faculty mentor/Co-author e-mail |
haneys2@uthscsa.edu |
Basic Science Rationale
(Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?) |
post a rationale |
| None available | |
|
Comments and Evidence-Based Updates on the CAT
(FOR PRACTICING DENTISTS', FACULTY, RESIDENTS and/or STUDENTS COMMENTS ON PUBLISHED CATs) |
post a comment |
| None available | |
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