In-vitro wear of natural tooth surface opposed with zirconia reinforced lithium silicate glass ceramic after accelerated ageing

Publication date: Available online 1 February 2018
Source:Dental Materials
Author(s): Salma M. Fathy, Michael V. Swain
ObjectiveTo evaluate the effect of different pH media on zirconia-reinforced lithium silicate glass ceramic and how they interact with opposing dentition after being aged in different pH cycling and high temperature conditions.MethodsTwenty-five rectangular shaped specimens were prepared from lithium silicate reinforced with zirconia blanks (Suprinity, Vita Zahnfabrick) and stored in different pH media (3 & 7.2) for different periods (24h & 7 days) at temperature (55°C). After their surface roughness (Ra) evaluation, aged ceramic specimens were subjected to cyclic abrasive wear with opposing natural teeth enamel for 150,000 cycles using a chewing simulator. Weight loss and Scanning Electron Microscope (SEM) images were used to evaluate the cyclic wear results.ResultsAfter different pH storage, ceramic group stored at 3 pH for 1-W (1 week) gave significantly higher mean Ra value (0.618μm±0.117) than control lowest mean value (0.357μm±0.054) before cyclic wear. On the other hand, it caused the least significant weight loss value (0.004gm±0.001) to opposing tooth enamel. There was significant tooth enamel weight loss (0.043gm±0.004) when opposed with ceramic group stored in 3 pH media for 24h (24-H). Their SEM images showed a prominent wear scar on enamel cusp tip. There was a significant increase in surface roughness Ra of ceramic material after abrasive cyclic wear.SignificanceGreat attention should be paid to Ra of this type of glass ceramic even if it is considered as minimal values. It can induce a significant amount of enamel tooth wear after a period equivalent to one year of intra-oral function rather than the significantly higher surface Ra of such ceramic type can do.



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