Paper: Wear of enamel opposing aged zirconia (AADR Annual Meeting (March 21-24, 2012))

Thursday, March 22, 2012: 3:30 p.m. - 4:45 p.m.

Presentation Type: Poster Discussion Session

S. JANYAVULA, N. LAWSON, D. CAKIR, P. BECK, L. RAMP, and J. BURGESS, University of Alabama at Birmingham, Birmingham, AL

Aging dental zirconia roughens its surface due to transformation from the tetragonal to the monoclinic state. Objectives: The effects of age-related roughening of zirconia on the wear of tooth enamel was measured. Methods: Specimens (n=8) were prepared by the manufacturer (3M ESPE) and divided into three groups: polished zirconia (LAVA), aged zirconia (LAVA), and a veneering porcelain (LAVA Ceram). Accelerated aging of zirconia was accomplished by autoclaving the zirconia specimens for 5 hours at 135º C and 2 bar pressure. Human incisor enamel to enamel wear (n=8) served as the control. Wear testing was conducted in a modified Alabama wear testing device. A load of 10N was applied at a frequency of 0.33Hz. 35% glycerine lubricant continuously flowed over the specimens. Human molar cusps were shaped into cones with a diamond bur. The bur preserved the enamel at the cusp tip and the cusps were used as antagonists in the wear device. Enamel cusps were duplicated and scanned by light profilometry at baseline and after 100,000 and 200,000 cycles of wear testing. Post-test scans were superimposed over baseline scans with ProScan software to calculate volumetric wear. Roughness of the ceramic specimens was measured before wear testing. Wear volumes and roughness values were analyzed with a one-way ANOVA and Tukey’s post-hoc analysis (alpha=0.05). Results:

Volumetric enamel wear (mm³)

Roughness (Ra)

100,000 cycles

200,000 cycles

Pre-testing

Polished zirconia

0.099±0.027^a

0.177±0.049^a

0.04±0.01^a

Aged zirconia

0.139±0.023^a

0.202±0.032^a

0.10±0.05^a

Veneering porcelain

0.359±0.053^c

0.512±0.051^c

0.35±0.05^a

Enamel

0.237±0.045^b

0.358±0.075^b

2.37±0.74^b

Similar superscripts represent statistically similar groups. Conclusions: Enamel wear against aged zirconia had similar roughness and produced similar wear of opposing enamel as polished zirconia. Both zirconia groups produced less enamel wear than the veneering porcelain or natural enamel.

Materials from 3M ESPE Supported by T32DE017607

This abstract is based on research that was funded entirely or partially by an outside source: NIDCR-T32DE017607

Keywords: Biomaterials, Ceramics, Dental materials, Wear and zirconia

See more of: Mechanical, Reliability, and Optical Properties of Enamel and Ceramics (PDS)
See more of: Dental Materials 3: Ceramic-based Materials and Cements

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	Volumetric enamel wear (mm³)		Roughness (Ra)
	100,000 cycles	200,000 cycles	Pre-testing
Polished zirconia	0.099±0.027^a	0.177±0.049^a	0.04±0.01^a
Aged zirconia	0.139±0.023^a	0.202±0.032^a	0.10±0.05^a
Veneering porcelain	0.359±0.053^c	0.512±0.051^c	0.35±0.05^a
Enamel	0.237±0.045^b	0.358±0.075^b	2.37±0.74^b

418 Wear of enamel opposing aged zirconia