IADR Abstract Archives
Wear characteristics of fine and nano-scale high-strength leucite glass-ceramics
Methods: Human enamel pins (Med.Ethics REC:06/Q0603/98) were wear tested against disc samples (n=12) of a commercial control (Ceramco-3, Dentsply) and experimental fine and nano-scale leucite glass-ceramics. Specimens were loaded (13.5N, MTS-Bionix-858 system) followed by a lateral excursion movement and a controlled cuspal contact time (0.25s) to complete the simulated masticatory cycles (300,000, 2Hz) under continuous flow of deionised water (37°C). Superimposition of digitised test surfaces before and after wear testing by non-contact 3D profilometry (Proscan-2000, Scantron) provided wear quantification data (volume/ mean-height loss) utilising the dedicated software and a novel protocol. Glass-ceramic disc/ tooth specimen groups were statistically compared (one-way ANOVA-on-ranks, p<0.05). Wear tested specimens were examined using SEM and Profilometry. Indicative surface roughness (Ra)/ waviness measurements (500 x,y line scans/specimen) were also performed on a glass-ceramic disc/tooth pair per group.
Results: Volume and mean-height loss results are listed below. The Ceramco-3 group exhibited distinct and patterned wear profile with parallel grooves. Less or non-oriented wear profile was exhibited by the experimental groups. All recorded Raand wave-height values for the experimental disc/tooth groups were lower than the Ceramco-3 group.
| Categories | Ceramco-3
|
Fine-scale Glass-ceramic |
Nano-scale Glass-ceramic |
Volume loss(mm3) (Discs) |
0.164(0.158,0.217)a |
0.190(0.154,0.214)a
|
0.175(0.148,0.204)a |
Volume loss(mm3) (Teeth) |
0.208(0.127,0.252)a |
0.133(0.110,0.151)b
|
0.112(0.074,0.149)b |
Mean-Height loss(μm)(Discs) |
61.8(55.2,72.0)a |
67.9(60.0,72.5)a |
65.0(56.8,70.5)a |
Mean-Height loss(μm)(Teeth) |
88.3(69.8,103.0)a |
65.7(56.0,77.5)b
|
49.9(43.5,70.7)c |
*Values represent medians (25%,75%percentiles).
Different superscript letters indicate significant (p<0.05) differences between groups within categories.
Conclusions: The experimental glass-ceramics exhibited significantly (p<0.05) lower antagonistic enamel wear when compared to a commercial control. Development of the fine and nano-scale leucite materials tested may support their use to achieve reduced rates of enamel loss.
This research was carried out in partial fulfillment of DrTheocharopoulos' PhD degree in Institute of Dentistry, Barts and The London SMD, QMUL 2011.