Enamel wear caused by monolithic zirconia crowns after 6 months of clinical use
Monolithic zirconia does not wear teeth more then previous porcelains. Adjustments mean you must polish the zirconia properly. MJ
Journal of Oral Rehabilitation
Summary
The purpose of
this study was to evaluate enamel wear caused by monolithic zirconia
crowns and to compare this with enamel wear caused by contralateral
natural antagonists. Twenty monolithic zirconia crowns were placed in 20
patients requiring full molar crowns. For measurement of wear,
impressions of both jaws were made at baseline after crown cementation
and at 6-month follow-up. Mean and maximum wear of the occlusal contact
areas of the crowns, of their natural antagonists and of the two
contralateral natural antagonists were measured by the use of plaster
replicas and 3D laser scanning methods. Wear differences were
investigated by the use of two-sided paired Student's t-tests
and by linear regression analysis. Mean vertical loss (maximum vertical
loss in parentheses) was 10 (43) μm for the zirconia crowns, 33 (112) μm
for the opposing enamel, 10 (58) μm for the contralateral teeth and 10
(46) μm for the contralateral antagonists. Both mean and maximum enamel
wear were significantly different between the antagonists of the
zirconia crowns and the contralateral antagonists. Gender and activity
of the masseter muscle at night (bruxism) were identified as possible
confounders which significantly affected wear. Under clinical
conditions, monolithic zirconia crowns seem to be associated with more
wear of opposed enamel than are natural teeth. With regard to wear
behaviour, clinical application of monolithic zirconia crowns is
justifiable because the amount of antagonistic enamel wear after
6 months is comparable with, or even lower than, that caused by other
ceramic materials in previous studies.
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