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Evaluation of Enamel Wear caused By Various Ceramic Materials and Gold

Evaluation of Enamel Wear caused By Various Ceramic Materials and Gold. Asmaa Elmaria DDS, MS Gary R. Goldstein, DDS T.V. Vijayaraghavan, PhD Raquel Z. Legeros, Ph.D NYU Kriser Dental Center. Enamel Wear. Occlusal contact - wear Enamel against enamel – 25-40 µm per/year*

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Evaluation of Enamel Wear caused By Various Ceramic Materials and Gold

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  1. Evaluation of Enamel Wear caused By Various Ceramic Materials and Gold Asmaa Elmaria DDS, MS Gary R. Goldstein, DDS T.V. Vijayaraghavan, PhD Raquel Z. Legeros, Ph.D NYU Kriser Dental Center

  2. Enamel Wear • Occlusal contact - wear • Enamel against enamel – 25-40 µm per/year* • Enamel against Restorative materials • Ceramic > Composite > Gold • Restorative material wear • Gold > composites > Glazed ceramics • *Lambrecht P, Braem M, Vuylsteke- wauters M, Vanherle G. Quantitative in vivo wear of human enamel. J Dent. Res. 1989; 68:1752-54.

  3. Enamel Wear -Factors Smoother surface  wears less • Rougher surface  greater wear • Harder surface  greater wear Bite and Chewing forces • Para-functional habits • pH, enamel character & morphology

  4. Jacobi & Shillinburg, Monasky and Taylor, Hudson et al. abrasive nature of porcelain Krejci et al. – rate of enamel wear function; surface finish,& hardness Krejci et al. Polishing of pressed glass ceramic led to less wear than glazing. Klausner et al. Ra values same for polished/glazed Raimondo et al. auto-glazed better vs. polished Prior studies

  5. Clinical factors • Occlusal adjustments a norm! • Requires re-glazing • Time, cost & Inconvenience • Alternative? • Polishing

  6. Polishing as an alternative • Avoid repeated firing • Avoid devitrification  loss of translucency • Less time consuming • Convenient

  7. Objective: • The purpose of this study was to evaluate enamel wear caused by a gold alloy and three ceramic substrates in the glazed and polished conditions.

  8. Null hypotheses to be tested: • Enamel wear caused by a glazed substrate is similar to that caused by a glazed surface that has been adjusted and polished. • Enamel wear caused by glazed or polished surface (after adjustment) is not dependent on the type of ceramic. • Enamel wear caused by a gold substrate is similar to any of the ceramic substrates in both surface conditions.

  9. Materials and Methods • Natural Enamel cusps, Ceramics, Gold • 10 samples/condition/material • Linear wear excursions (10,000 cycles) • Track length = 6 mm • Surface roughness (Ra)- Before and after

  10. Materials Fusion Temp. Glazing Temp. Manufacturer Type III Gold 75% Au, 11.5% Ag, 10% Cu, 3% Jeneric/Pentron, Wellingford, CT Composition/ IPS-Empress 1100 °C 1100 °C 63 SiO2, 17.7 Al2O3, 11.2 K2O, 4.2 Na2O, 1.6 CaO, 0.7BaO, 0.6 B2O3, 0.4 CeO2, 0.2 TiO2 (40-50%) Williams/Ivoclar, Amherst, NY (Leucite content, %) Procera All-Ceram 900 °C 920 °C Na2O, K2O, Al2O3, SiO2, CaO, SnO2, Y2O3, CeO2 (15-20%) Procera/Sandvic AB, Stockholm, Sweden Finesse Porcelain 750 °C 760 °C Na2O, K2O, Al2O3, SiO2 (8-10%) Ceramco Inc. Burlington N.J. Restorative Materials

  11. Materials and Methods

  12. Materials and Methods • Measurement of enamel wear • From trace of enamel cusp profile • Qualitative wear (SEM)

  13. Materials and Methods

  14. Results • t-Test, pooled variance, 2 tail; p<0.05 • One-way ANOVA,followed by Scheffe test; p=0.05 • SE Micrographs

  15. Material and Condition N Subset for alpha = .05 1 2 3 Gold 10 .11296 Finesse, Pol 10 .63694 .63694 All-Ceram, Pol 10 .76460 .76460 All-Ceram, Glz 10 .97508 .97508 IPS-Empress Pol 10 1.05224 1.05224 Finesse, Glz 10 1.15380 1.15380 IPS-Empress Glz 10 1.51756 Sig. .060 .249 .197 Multiple comparisonsEnamel height loss

  16. Material Before wear After wear P Value Gold 0.090.025 0.290.25 0.03 Glazed Finesse 0.720.19 0.800.26 0.4 Polished Finesse 0.370.14 0.440.13 0.09 Glazed All-Ceram 0.170.05* 0.440.15 0.001 Polished All-Ceram 0.230.11* 0.450.21 0.01 Glazed IPS Empress 0.460.19 0.640.41 0.3 Polished IPS Empress 0.150.05 0.280.09 0.002 Surface roughness, Ra (mm)Before and after wear (N=10 per group), Student's t-Test, significant differences based on p = 0.05

  17. Gold Alloy Left: low magnification (35X),the track created by the enamel cusp at 10,000 cycles. Right: higher magnification(350X) showing polishing lines and smoother track region. Ra: 0.09- 0.29 µm-before & after wear)

  18. Finesse- polished condition (35X). The track region has been outlined (continuous line) and reveals continuous grooves. The background reveals a pitted appearance with dark isolated regions indicated by arrows (background), suggesting removal of some micro-structural constituent . (Ra: 0.37-0.44 µm - -before & after wear)

  19. IPS-Empress- polished condition The track region is visible and reveals a smoother surface than the surrounding background. Polishing marks can be seen in the background region. Debris is visible as bright white discontinuous regions. (35 X) (Ra: 0.15-0.28 µm -before & after wear)

  20. IPS-Empress- glazed condition Left: low magnification (35X) Right: Higher magnification (500X) (Ra: 0.46-0.64µm - -before & after wear)

  21. Discussion • Polishing produced a smoother surface only in two materials • Grit size- polishing material • Grain or crystal size, phases & hardness –substrate, glazing Pressure and Temperature, • Leucite content increased hardness* • IPS-Empress and Finesse • Smoothness and roughness • (polishing and wear) *Kingery WD: Introduction to Ceramics, John Wiley and Sons, Inc., 1960, 597-599.

  22. Discussion • Adjustment & Polishing • Gross & minor wear • Removal of glaze • Traditional porcelain – would require re-glazing unglazed porc.- significant  modulus of rupture • Newer generation porcelain –greater than normal adjustment may be possible- then polishing • Density, processing mode, homogeneity, leucite crystalline additions

  23. Mean Roughness Value • Roughness and polishing • Ra value in this study was below 1µm • Roughness and wear • Smooth - higher wear ! • Rough – lower wear !

  24. Conclusion Ranking of enamel cusp height loss • Gold < PFIN <PALC <GALC <PEMP <GFIN <GEMP • Ranking of mean Ra values • Gold < PEMP<GALC<PALC<PFIN<GEMP<GFIN

  25. Conclusions • Gold caused significantly less enamel wear than ceramic substrates • Glazed surfaces exhibited significantly more enamel wear than polished surfaces • Finesse caused the least enamel wear among all the ceramic materials, and was not significantly different than Gold • Empress caused the greatest wear

  26. Thank you

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