Evaluation of enamel wear caused by various ceramic materials and gold
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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
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
Enamel Wear Materials and Gold

  • 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.


Enamel wear factors
Enamel Wear -Factors Materials and Gold

Smoother surface  wears less

  • Rougher surface  greater wear

  • Harder surface  greater wear

    Bite and Chewing forces

  • Para-functional habits

  • pH, enamel character & morphology


Prior studies

Jacobi & Shillinburg, Monasky and Taylor, Hudson et al. Materials and Gold

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


Clinical factors
Clinical factors Materials and Gold

  • Occlusal adjustments a norm!

    • Requires re-glazing

    • Time, cost & Inconvenience

  • Alternative?

    • Polishing


Polishing as an alternative
Polishing as an alternative Materials and Gold

  • Avoid repeated firing

    • Avoid devitrification  loss of translucency

    • Less time consuming

    • Convenient


Objective
Objective: Materials and Gold

  • 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.


Null hypotheses to be tested
Null hypotheses to be tested: Materials and Gold

  • 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.


Materials and methods
Materials and Methods Materials and Gold

  • 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


Restorative materials

Materials Materials and Gold

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


Materials and methods1
Materials and Methods Materials and Gold


Materials and methods2
Materials and Methods Materials and Gold

  • Measurement of enamel wear

    • From trace of enamel cusp profile

    • Qualitative wear (SEM)


Materials and methods3
Materials and Methods Materials and Gold


Results
Results Materials and Gold

  • t-Test, pooled variance, 2 tail; p<0.05

  • One-way ANOVA,followed by Scheffe test; p=0.05

  • SE Micrographs


Multiple comparisons enamel height loss

Material and Condition Materials and Gold

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


Surface roughness ra m m before and after wear

Material Materials and Gold

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


Gold alloy
Gold Alloy Materials and Gold

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)


Finesse polished condition
Finesse- polished condition Materials and Gold

(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)


Ips empress polished condition
IPS-Empress- polished condition Materials and Gold

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)


Ips empress glazed condition
IPS-Empress- glazed condition Materials and Gold

Left: low magnification (35X)

Right: Higher magnification (500X)

(Ra: 0.46-0.64µm - -before & after wear)


Discussion
Discussion Materials and Gold

  • 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.


  • Discussion1
    Discussion Materials and Gold

    • 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


    Mean roughness value
    Mean Roughness Value Materials and Gold

    • Roughness and polishing

      • Ra value in this study was below 1µm

    • Roughness and wear

      • Smooth - higher wear !

      • Rough – lower wear !


    Conclusion
    Conclusion Materials and Gold

    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


  • Conclusions
    Conclusions Materials and Gold

    • 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


    Thank you
    Thank you Materials and Gold


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