Background and Aim: The Wear resistance of acrylic teeth plays an important role in denture longevity. The purpose of this study was to compare the Tooth Wear rate of three Iranian manufactured artificial teeth with the one manufactured in Italy.Materials and Methods: In this experimental in vitro study four brands of artificial teeth including Ivoclar, Glamour, Apple and B.star were used. Sixteen mandibular molars were selected from each band. Eight samples from each brand of teeth were loaded under 2 Kg compressive forces in the presence of artificial saliva. The aluminum oxide mullet was used with 5000 and 10000 cycles. The other 8 samples were loaded under a 4Kg compressive force under the same conditions. The data were analyzed with ANOVA test.Results: The results showed that weight loss (Wear) by aluminum oxide mullet under 2kg force, 5000 cycle, for acrylic teeth was as follows: Ivoclar 0.0097 ± 0.0028, Glamor 0.0122 ± 0.0037, Apple 0.0120±00038And B.star 0.0098 ± 0.0030mgr. Also, under the same conditions and at 10, 000 cycle, the weight loss was 0.0123 ± 0.0023, 0.0156 ± 0.0042, 0.0147 ± 0.0039 and B.Star 0.0119 ± 0.0029mg respectively. There is not significant differences between the groups.. (p<0.4).by increasing the force to 4 Kg there is not significant differences between the groups (p<0.5).Conclusion: The results of this in-vitro study showed that there is not any significant differences between Wear resistance in four brand of artificial acrylic teeth.

Background and Aim: Enamel Wear is among the main disadvantages of ceramic restorations. Recently, use of full zirconia crowns without dental porcelain has been suggested. The aim of this study was to compare the effect of feldspathic porcelain and zirconia on the Wear of natural teeth.Materials and Methods: In this experimental study, 22 zirconia specimens were fabricated; out of which, 11 specimens were polished and chosen as zirconia specimens while the remaining 11 were used to fabricate porcelain specimens. A total of 22 natural human teeth were also obtained. The natural teeth were photographed by a stereomicroscope in a fixed position and the distance from the cusp tip to a reference point was measured. Next, 11 teeth opposed zirconia and the remaining 11 opposed porcelain specimens in a chewing simulator and subjected to 120,000 masticatory cycles. The teeth were photographed again and the greatest difference between the before and after values was recorded.Results: The mean (± standard deviation) Wear rate was 153.8±95.68 and 306.3±127.74, in the zirconia and porcelain groups, respectively; and the two groups had a statistically significant difference in this respect (P=0.007).Conclusion: The mean Wear was significantly lower in teeth opposing zirconia than in those opposing feldspathic porcelain.