Page 18 - GP Fall 2020

The Effect of Different Dental Ceramic Systems on
The Wear of Human Enamel: An in vitro Study

Abstract In terms of opposing enamel height loss, opposing enamel tooth structure than on
Statement of problem. The wear of tooth the Lava Plus Zirconia system showed the cast gold alloy. 13-16 Variations in ceramic
structure opposing different advanced den- lowest mean value of 27.5 μm. The mean composition, microstructure, and fusing
tal ceramic systems requires investigation. value for IPS e.max CAD system was temperatures, did not necessarily guarantee
27.91 μm, control enamel was 29.08 μm, low enamel wear. 8,17 However, a signifi-
Purpose. The purpose of this in vitro study IPS e.max Press system was 33.25 μm, and cant difference in the amount of opposing
was to compare the wear of advanced ce- the Noritake Super Porcelain EX-3 system enamel wear has been found between dif-
ramic systems against human enamel an- was 34.75 μm. This study showed no stat- ferent types of restorations. 18-20
tagonists. ically significant differences between the
groups in opposing enamel volume loss The results of a randomized, controlled
Materials and Methods. Four ceramic (p-value .225) and opposing enamel height clinical trial of the full contour lithium dis-
systems (IPS e.max Press, IPS e.max CAD, loss (p-value .149). ilicate glass-ceramic restorations, in which
Noritake Super Porcelain EX-3, LAVA Plus the investigator analyzed the volumetric
Zirconia) and one control group, contain- Conclusions. Within the limitation of this loss of enamel and ceramic antagonist sur-
ing human enamel specimens, were used in vitro study, it can be concluded that there faces showed that they were wear-resistant,
in this study (n=12). All specimens were were no differences in liner and volumetric as well as wear-friendly, to the opposing
fabricated in 11 mm diameter and 3 mm reduction of enamel cusps abraded against enamel in a manner similar to that of ceram-
thickness disks. The mesio-palatal cusps of enamel disks and all other ceramic speci- ics typically used for veneering metal-ce-
the maxillary third molars were prepared to mens. All ceramic systems exhibited high ramic or all-ceramic crowns. Conversely,
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serve as the enamel styluses. All specimens durability and were wear-friendly to oppos- glazing of heat-pressed crowns before in-
were embedded individually in 25 mm au- ing natural dentition. sertion, has resulted in a significantly lower
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topolymerizing acrylic resin blocks. Wear material volume loss when compared to the
testing was performed by using the cyclic Clinical Implications mean volume loss of enamel after one year
loading machine and a newly designed Antagonistic enamel wear against the stud- of clinical performance.
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wear stimulating device (TA-317C Multi- ied ceramic materials exhibited wear rates
ple Sample Vertical Friction Wear Device) within the range of normal enamel, al- Zirconia holds a unique place amongst ox-
developed by the author. The procedure though the in vitro model cannot simulate ide ceramics due to its excellent mechani-
was run in the form of two-body contact the oral environment with all its biologic cal properties. Zirconia is available for the
of bi-directional back-and-forth sliding variables. An understanding of the behav- fabrication of single and multi-unit resto-
movements in which a stylus runs against a ior of different materials and the involving rations, in combination with CAD/CAM
flat surface with no lifting of the stylus. All factors may help reduce the wear process. techniques, and is considered a good choice
enamel styluses and cusps were scanned for posterior fixed partial dentures. 23-26 Its
using the SmartOptics Activity 880 Digital Introduction long-term clinical results indicated that it
Scanner. Data of baseline and follow-up The use of tooth-colored materials for fab- is equivalent to those of porcelain-fused-
scans were collected and compared with ricating dental restorations has become to-cast crowns although a recent in vivo
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the 3D and 2D digital inspection software more popular recently. 1-4 The search for study showed that the wear of natural
Qualify 2012 (Geomagic), which aligned all-ceramic restorations of high strength, enamel opposing zirconia crowns was sig-
the models and detected the geometrical enhanced marginal integrity, and improved nificantly less than metal ceramic crowns.
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changes, the wear, caused by antagonist color quality has resulted in the introduc- When monolithic translucent and shaded
specimen. A one-way analysis of variance tion of dental ceramics with better physical experimental zirconia samples were exam-
(ANOVA) was performed to analyze the and mechanical properties. Such proper- ined, they yielded superior wear behavior,
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collected data. ties have led to a wider application of all- and lower antagonistic wear compared to
ceramic restorations in the posterior region monolithic lithium disilicate, veneering

Results. After 125,000 bi-directional load- of the mouth. Ideally, loads placed on the porcelain, and enamel samples. 29-31 An in
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ing cycles, the mean value of opposing occlusal surfaces of teeth should be kept at vitro study reported that monolithic zir-
enamel volume loss for enamel disks of the a level commensurate with normal physio- conia produced a similar enamel wear to
control group was 37.08 μm , which was logic wear and aging. When compared to conventional feldspathic porcelain. Park
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the lowest mean value among the groups; the mean annual occlusal wear of human et al reported significantly less wear of the
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IPS e.max Press system was 39.75 μm ; tooth enamel (15-38 mu), dental ceram- antagonistic tooth against different CAD/
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IPS e.max CAD was 40.58 μm ; Noritake ics are considered wear-resistant and tend CAM anatomic contour zirconia ceram-
Super Porcelain EX-3 system was 45.08 to cause damage to the opposing enamel, ics than the veneering ceramic. Howev-

μm ; and the Lava Plus Zirconia system which varies by the ceramic material used. 9- er, polished monolithic zirconia showed
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was 48.66 μm . 12 Results of several studies have indicated a significantly lower wear rate on enamel
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that ceramic materials cause more wear on antagonists than that produced by glazed
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