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Title Polished Zirconia Crowns Wear Opposing Enamel Less Than Glazed Zirconia Crowns
Clinical Question In a patient receiving a zirconia crown, will polishing instead of glazing the crown decrease the amount of enamel wear on the opposing dentition?
Clinical Bottom Line Results indicate that polished zirconia creates less wear of opposing enamel when compared to zirconia that has been glazed.
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) 24957813Passos/20147 in vitro studiesSystematic Review
Key resultsFour of the seven in vitro studies included in this review directly addressed the clinical question. Three of those used sliding contact and found that polished zirconia surfaces produced less wear of opposing enamel cusps when compared to glazed zirconia. The fourth study, done without sliding contact, found there to be no difference. Variations in test methods did not allow for comparison of wear rates between studies.
#2) 25257823Lawson/20148 groups consisting of (n=8) in vitro specimensLaboratory study
Key resultsIn this more recent study, Lawson compared the amount of enamel wear produced by sliding contact of 8 different restorative specimens. Groups studied were lithium disilicate adjusted (A), lithium disilicate adjusted and polished (AP), lithium disilicate glazed (AG), veneering porcelain, zirconia adjusted (A), zirconia adjusted and polished (AP), and zirconia adjusted and glazed (AG). Data was analyzed with ANOVA and Tukey-Kramer post hoc tests (α=0.05). Results indicated that polished zirconia (AP) produces less wear of enamel opposing cusps (0.033 ±0.11mm3) than glazed zirconia (AG) (0.068 ±0.20mm3).
#3) 24199603Park/20146 groups of 8 in vitro specimensLaboratory study
Key resultsIn this study (also more recent that the Passos systematic review), Park compared the sliding 2-body wear of 6 CAD/CAM restorative antagonists on opposing enamel. Groups tested were Zirkonzahn Y-TZP Polished (ZPP), Stained (ZPS), and Stained/Glazed (ZPG) + Acucera Y-ZTP (AZ), Wieland y-ZTP WZ), and Noritake feldspathic ceramic (FC). Data was analyzed with 1-way ANOVA and Tukey tests for post hoc analysis (α=0.05). Results indicated that polished zirconia (ZPP) produces less wear of enamel opposing cusps (1.2 ±0.4mm3 estimated from graph) than glazed zirconia (ZPG) (3.1 ±1.6 mm3 again estimated from graph); P<0.01.
Evidence Search ((("Dental Enamel"[Mesh]) AND "Tooth Wear"[Mesh])) AND antagonist. [Passos] (((((Enamel) AND wear) AND glaze) AND zirconia. [Lawson] (((("dental enamel"[MeSH Terms]) AND "tooth wear"[MeSH Terms]) AND "zirconium"[MeSH Terms])) AND porcelain crown [Park]
Comments on
The Evidence
Validity: In vitro/bench-top studies rank relatively low on the hierarchy of evidence and should not be regarded as highly as well-controlled clinical studies. Having said that, the results of these bench-top studies consistently demonstrated that polished zirconia produces less sliding 2-body wear of opposing enamel that glazed zirconia.
Applicability The information presented in the CAT is applicable to any restorative dentist using zirconia for coronal restorations and considering whether or not to polish the restoration prior to seating.
Specialty/Discipline (General Dentistry) (Prosthodontics) (Restorative Dentistry)
Keywords Zirconia, polishing, glazed, wear
ID# 2803
Date of submission: 12/12/2014spacer
E-mail womackj@uthscsa.edu
Author James Michael Womack, DDS
Co-author(s) e-mail
Faculty mentor/Co-author Stephan J. Haney, DDS
Faculty mentor/Co-author e-mail haneys2@uthscsa.edu
Basic Science Rationale
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