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Abrasion wear resistance of different artificial teeth opposed to metal and composite antagonists

Authors:
  • Sculpere Odontologia e Arte - Campinas, SP - Brazil

Abstract and Figures

One of the most important properties of artificial teeth is the abrasion wear resistance, which is determinant in the maintenance of the rehabilitation's occlusal pattern. This in vitro study aims to evaluate the abrasion wear resistance of 7 brands of artificial teeth opposed to two types of antagonists. Seven groups were prepared with 12 specimens each (BIOLUX & BL, TRILUX & TR, BLUE DENT & BD, BIOCLER & BC, POSTARIS & PO, ORTHOSIT & OR, GNATHOSTAR & GN), opposed to metallic (M & nickel-chromium alloy), and to composite antagonists (C & Solidex indirect composite). A mechanical loading device was used (240 cycles/min, 4 Hz speed, 10 mm antagonist course). Initial and final contours of each specimen were registered with aid of a profile projector (20x magnification). The linear difference between the two profiles was measured and the registered values were subjected to ANOVA and Tukey's test. Regarding the antagonists, only OR (M = 10.45 +/- 1.42 microm and C = 2.77 +/- 0.69 microm) and BC (M = 6.70 +/- 1.37 microm and C = 4.48 +/- 0.80 microm) presented statistically significant differences (p < 0.05). Best results were obtained with PO (C = 2.33 +/- 0.91 microm and M = 1.78 +/- 0.42 microm), followed by BL (C = 3.70 +/- 1.32 microm and M = 3.70 +/- 0.61 microm), statistically similar for both antagonists (p>0.05). Greater result variance was obtained with OR, which presented the worse results opposed to Ni-Cr (10.45 +/- 1.42 microm), and results similar to the best ones against composite (2.77 +/- 0.69 microm). Within the limitations of this study, it may be concluded that the antagonist material is a factor of major importance to be considered in the choice of the artificial teeth to be used in the prosthesis.
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ABSTRACT
www.fob.usp.br/jaos or www.scielo.br/jaos
J Appl Oral Sci. 2009;17(5):451-6
ABRASION WEAR RESISTANCE OF DIFFERENT
ARTIFICIAL TEETH OPPOSED TO METAL AND
COMPOSITE ANTAGONISTS
Pâmela Carbone MELLO1, Abílio Ricciardi COPPEDÊ1, Ana Paula MACEDO2, Maria da Gloria Chiarello de MATTOS3,
Renata Cristina Silveira RODRIGUES4, Ricardo Faria RIBEIRO3
1- DDS, MSc, Graduate student, Department of Dental Materials and Prosthodontics, Dental School of Ribeirão Preto, University of São Paulo,
Ribeirão Preto, SP, Brazil.
2- Laboratory technician (Electrical engineer), Department of Dental Materials and Prosthodontics, Dental School of Ribeirão Preto, University of
São Paulo, Ribeirão Preto, SP, Brazil.
3- DDS, MSc, PhD, Full Professor, Department of Dental Materials and Prosthodontics, Dental School of Ribeirão Preto, University of São Paulo,
Ribeirão Preto, SP, Brazil.
4- DDS, MSc, PhD, Assistant Professor, Department of Dental Materials and Prosthodontics, Dental School of Ribeirão Preto, University of São
Paulo, Ribeirão Preto, SP, Brazil.
Corresponding address: Ricardo Faria Ribeiro - Departamento de Materiais Dentários e Prótese, Faculdade de Odontologia de Ribeirão Preto,
Universidade de São Paulo. Av. do Café, s/n, 14040-904 - Ribeirão Preto, SP - Brasil. - Phone: +55-16-3602-4046 / Fax: +55-16-3633-0999 - e-mail:
rribeiro@forp.usp.br
Received: July 30, 2008 - Modification: November 09, 2008 - Accepted: May 18, 2009
ne of the most important properties of artificial teeth is the abrasion wear resistance, which is determinant in the maintenance
of the rehabilitation’s occlusal pattern. Objectives: This in vitro study aims to evaluate the abrasion wear resistance of 7 brands of
artificial teeth opposed to two types of antagonists. Material and methods: Seven groups were prepared with 12 specimens each
(BIOLUX – BL, TRILUX – TR, BLUE DENT – BD, BIOCLER – BC, POSTARIS – PO, ORTHOSIT – OR, GNATHOSTAR –
GN), opposed to metallic (M – nickel-chromium alloy), and to composite antagonists (C – Solidex indirect composite). A mechanical
loading device was used (240 cycles/min, 4 Hz speed, 10 mm antagonist course). Initial and final contours of each specimen were
registered with aid of a profile projector (20x magnification). The linear difference between the two profiles was measured and the
registered values were subjected to ANOVA and Tukey’s test. Results: Regarding the antagonists, only OR (M = 10.45 ± 1.42 m
and C = 2.77 ± 0.69 m) and BC (M = 6.70 ± 1.37 m and C = 4.48 ± 0.80 m) presented statistically significant differences (p <
0.05). Best results were obtained with PO (C = 2.33 ± 0.91 m and M = 1.78 ± 0.42 m), followed by BL (C = 3.70 ± 1.32 m and
M = 3.70 ± 0.61 m), statistically similar for both antagonists (p>0.05). Greater result variance was obtained with OR, which
presented the worse results opposed to Ni-Cr (10.45 ± 1.42 m), and results similar to the best ones against composite (2.77 ± 0.69
m). Conclusions: Within the limitations of this study, it may be concluded that the antagonist material is a factor of major importance
to be considered in the choice of the artificial teeth to be used in the prosthesis.
Key words: Tooth, artificial. Comparative study. Tooth abrasion.
INTRODUCTION
The abrasion wear of artificial teeth used in prosthetic
rehabilitation treatments is of great clinical interest. Worn
teeth alter the vertical dimension of occlusion, which may
lead to craniofacial disorders, reduce chewing efficiency,
cause fatigue of masticatory muscles, increase patient
discomfort and impair the esthetics4,12,13,19. In order to
maintain adequate function and stable occlusion, more
attention should be given to the choice of the artificial teeth,
which should be made considering the material of the
antagonist teeth2,6.
There are three options of materials for posterior artificial
teeth: porcelain, acrylic resin and metal. In removable
prostheses, acrylic resin teeth are used more frequently than
porcelain teeth5,7. Acrylic resin teeth present some
advantages over porcelain teeth, such as: less brittleness,
better connection to the denture base material, easier occlusal
adjustments and repolishing, more natural appearance and
less chewing noises15,18.
The low resistance to abrasion wear of the acrylic resin
teeth consists in a limitation of these teeth. They do not resist
parafunctional habits, and many times it is hard to maintain
the vertical dimension. In order to improve abrasion wear
resistance, acrylic artificial teeth with better mechanical
properties have been developed, such as the interpenetrated
451
polymer network (IPN) resin teeth, with polymer double-
crossed links (DCL), and resin teeth with addition of
inorganic agents in their composition15-17. However, a recent
study reported that these teeth, when compared to
conventional ones, have worse adhesion to the denture base
resin11.
The objective of this study was to evaluate the in vitro
abrasion wear resistance of 7 commercial brands of artificial
denture teeth (BIOLUX, TRILUX, BLUE DENT,
BIOCLER, POSTARIS, ORTHOSIT, GNATHOSTAR),
opposed to metallic antagonists (M – nickel-chromium alloy)
and composite antagonists (C – Solidex indirect composite).
Although some of these artificial teeth are commercially
available only in the Brazilian market, all of them have
formulations found worldwide and can therefore indicate
the expected results when used in dental prostheses.
MATERIAL AND METHODS
Figure 1 shows the artificial denture teeth evaluated in
this study. Seven groups of 12 specimens each were prepared
and divided in two subgroups: one group was tested opposed
to metallic antagonists (M – Ni-Cr alloy [Vera Bond II, Aalba
Dent. Inc., Cordelia, CA, USA]), and another group was
tested opposed to composite antagonists (C – indirect
composite, (Solidex [Shofu Inc., Tokyo, Japan]). Six
maxillary first premolars of each brand were used (N = 84).
The Ni-Cr alloy was selected because it is extensively used
in oclusal surfaces of fixed partial dentures, as clinically
observed in partially edentulous patients.
The 84 specimens were included in 1-inch PVC rings
with self-curing acrylic resin, using a custom-made
parallelometer (Ribeirão Preto Dental School, University
of São Paulo), with a griping tip that stabilized the specimen
FIGURE 1- Groups of artificial teeth
*Based on manufacturers’ informations
Groups
BD
BL
BC
TR
PO
GN
OR
N
12
12
12
12
12
12
12
Composition*
High-density
polymethylmethacrylate, cross-
linked
Polymethylmethacrylate;
Polymerized Ethyleneglycol
Dimethacrylate (EDMA);
Fluorescent; Biocompatible
Pigments
Polymethylmethacrylate, cross-
linked; Fluorescent
Polymethylmethacrylate;
Polymerized Ethyleneglycol
Dimethacrylate (EDMA);
Fluorescent; Biocompatible
Pigments
Synthetic polymer based on
Polymethylmethacrylate;
double cross linked
Synthetic polymer based on
Polymethylmethacrylate
Microfilled resin composite
(Isosit+Inorganic fillers)
(urethane dimethacrylate –
UDMA)
Commercial Brand
BLUE DENT
BIOLUX
BIOCLER GII
TRILUX
SR POSTARIS DCL
GNATHOSTAR
SR ORTHOSIT PE
Manufacturer
Blue Dent Dental, Pirassununga,
Brazil
VIPI Indústria, Comércio,
Exportação e Importação de
Produtos Odontológicos Ltda,
Pirassununga, Brazil
DentBras Indústria, Comércio,
Importação e Exportação de
Produtos Odontológicos Ltda,
Pirassununga, Brazil
VIPI Indústria, Comércio,
Exportação e Importação de
Produtos Odontológicos Ltda,
Pirassununga, Brazil
Ivoclar Vivadent AG.Schaan,
Liechtenstein
Ivoclar Vivadent AG.Schaan,
Liechtenstein
Ivoclar Vivadent AG.Schaan,
Liechtenstein
ABRASION WEAR RESISTANCE OF DIFFERENT ARTIFICIAL TEETH OPPOSED TO METAL AND COMPOSITE ANTAGONISTS
452
during the inclusion.
For preparation of the antagonist tablets, a 20-mm-
diameter polytetrafluoroethylene matrix was manufactured
in the Department of Dental Materials and Prosthodontics
of Ribeirão Preto Dental School, University of São Paulo
(DDMP), with 2- and 3-mm-thick spacers. Using 2-mm-
thick spacers and Picodip wax (Renfert GmbH, Hilzingen,
Germany) liquefied in a wax dipping pot (Hotty Led, Renfert,
Hilzingen, Germany), patterns were obtained, and were
included with phosphate-based investment (Termocast,
Polidental Ind. Bras. Ltda, São Paulo, Brazil), and cast with
Ni-Cr alloy in the Discovery Plasma casting machine (EDG
Equipments and Controls Ltda, São Carlos, SP, Brazil),
under vacuum and inert argon atmosphere. The castings
obtained were sandblasted with 100-m aluminum oxide
stream, under 80 psi (5.62 kgf/cm2) pressure. Using the same
matrix, but with the 3-mm-thick spacer, 12 other tablets were
obtained with the Solidex composite. Each tablet was
obtained using an incremental technique, according to which
2 composite increments were built, each one subjected to a
90-s curing cycle in a light-curing unit (UniXS, Heraeus
Kulzer GmbH, Hanau, Germany). The polymerized
specimen was retrieved from the matrix and subjected to
more 90-s of light curing.
According to the DIN method stated by the ISO/TS
14569-2 standard, the surface of the antagonist tablet must
have a surface roughness of 0.75 m. Thus, all antagonist
tablets were prepared with 300-, 600- and 1200-grit silicon
carbide paper in a decreasing sequence of abrasiveness, and
their surface roughness was read in a surface roughness meter
(SPJ-2, Mitutoyo, Tokyo, Japan).
Before abrasion wear tests, the specimens were taken to
a profile projector (Nikon 6C, Tokyo, Japan) with a 20x
magnification and were individually placed in a positioning
platform that allows further placement of the specimen in
the same position for the post-test measurements. A vegetable
graph paper was used to obtain each specimen’s profile.
The original profile of the specimens was traced for posterior
analysis of contour changes.
The abrasion wear tests were performed in the
mechanical loading device developed at the DDMP. In this
device, an electrical motor moves a lever arm with a 265
cycles/min speed. An acrylic recipient is attached to the
device´s lever arm, and performs a 10-mm course, resulting
in a linear speed of 88 mm/s. The test assembly was installed
inside the acrylic recipient.
Specimens were placed in a pole with vertical
adjustment, allowing it to be positioned over the antagonist.
Once the pole was completely released, a load of 5 N,
corresponding to the whole weight of the assembly, was
applied to the specimens. This mechanical loading device
was designed according to the ISO/TS 14569-2 standard
(Dental Materials – Guidance on testing of wear – Part 2:
Wear by two – and/or three-body contact, 2001) under the
Freiburg Method. The tests completed 40,000 cycles,
simulating approximately 120 days of normal oral function4
(150 min, 4 Hz), with specimens and antagonists completely
immerse in deionized water (Figure 2).
Specimens and composite antagonists were stored in
distilled water at 37o ± 1oC during 7 days before the tests. In
the test machine, the antagonist tablet was placed into a
recipient with deionized water. Immediately after removal
of the water storage, the specimens were dried with absorbent
paper and a gentle air stream, and had their final contour
traced in the profile projector (Nikon 6C, Tokyo, Japan),
over the initial profile traced. The measure of the abrasion
wear was determined by the linear difference between the
two profiles, utilizing a digital paquimeter (Mitutoyo CD –
15C, Japan, Tokyo) accurate to the nearest 0.01 mm (Figure
3).
The wear values (m) of all tested specimens, grouped
by antagonist, were subjected to one-way ANOVA and
Tukey’s test. The paired t-test was used for comparisons
within each specimen group, among different antagonists,
All statistics were performed using the SPSS statistical
package (SPSS Inc., Chicago, IL, USA).
RESULTS
The results obtained in the abrasion wear resistance tests
by the artificial teeth are shown in Figure 4.
There were statistically significant differences (p=0.001)
for comparisons among the different artificial teeth against
FIGURE 2- Wear abrasion test device
MELLO P C, COPPEDÊ A R, MACEDO A P, MATTOS M da G C de, RODRIGUES R C S, RIBEIRO R F
453
composite antagonist. PO (2.33 ± 0.91 m) and OR (2.77 ±
0.69 m), which had the lowest wear mean values, were
significantly different from groups BC (4.48 ± 0.80 m)
and GN (4.50 ± 0.73 m), which had the highest wear mean
values.
Statistically significant differences (p=0.000) were found
when the groups were compared against metallic antagonist.
OR (10.45 ± 1.42 m) presented the highest wear mean
value, and differed significantly from all other groups
(p<0.001). There were significant differences (p<0.05)
between BC (6.70 ± 1.37 m) and TRI (4.30 ± 0.43 m),
BL (3.70 ± 0.61 m) and PO (1.78 ± 0.42 m). Significant
differences (p<0.05) were also found when BD (5.37 ± 1.65
m) and TRI (4.30 ± 0.43 m) were compared to PO (1.78
± 0.42 m), which had the lowest wear mean values (Figure
3).
In order to compare the wear for each group caused by
the two types of antagonists, a paired-sample t-test were
performed. Significant differences were observed for BC
(p=0.007), which presented mean wear of 4.48 ± 0.80 m
against composite and 6.70 ± 1.37 m against metal, and
for OR (p=0.000), which presented mean wear of 2.77 ±
0.69 m against composite and 10.45 ± 1.42m against
metal. All other groups had no statistically significant
differences from each other (p>0.05).
No wear was observed in the antagonists.
DISCUSSION
This study excluded clinical variables, such as
neuromuscular forces and movements, saliva pH and
lubrication, oral hygiene habits and diet, because according
to previous studies, those factors are very difficult to control,
FIGURE 3- Measure of abrasion wear determined by the linear difference between the initial and final profiles
FIGURE 4- Original values, mean values and standard deviations of all specimens opposed to the antagonists (metallic, NiCr,
and composite, Solidex) after the abrasion wear resistance tests (in µm) - please refer to text in order to follow statistically
significant differences
ABRASION WEAR RESISTANCE OF DIFFERENT ARTIFICIAL TEETH OPPOSED TO METAL AND COMPOSITE ANTAGONISTS
454
and are costly and time consuming10,15.
Prosthetic rehabilitation success depends on adopting
correct procedures in order to obtain comfort, function and
esthetics. The choice of the materials that will replace
missing dental structures is a critical clinical issue for both
the professional and the patient. The dentist has to have
knowledge and discernment to adjust the patient’s
expectations to the characteristics of the materials indicated
for the case. Also, the dentist must be familiar with the
properties of the various artificial teeth available in the
market and must be aware of patient’s characteristics, such
as diet and presence of parafunctional habits, in order to
obtain the best possible treatment prognosis1,7.
Stober, et al.15 (2006) has stated that natural enamel is
an unsuitable antagonist material for standardized wear tests
because the composition, shape and wear properties of
biological substances are highly variable. Based on this
information, human enamel was not used in this study.
However, it should be considered that the interaction with
the enamel provide important data for the evaluation of
artificial teeth.
In the two-body wear test used in the present study, there
is direct contact between the tested material and its respective
antagonist, with no intermediate material, but running water.
Other studies, however, used an intermediate material to
simulate the food bolus. Kadokawa, et al.9 (2006) evaluated
the abrasion wear and other abrasive properties of porcelain,
gold alloy, composite resin and human enamel using 2-body
and 3-body conditions (PMMA slurry). The authors
concluded that the wear values in 3-body wear were
significantly smaller.
According to Whitman, et al.17 (1987) and Hirano, et
al.7 (1998), artificial teeth made of improved acrylic resin
(IPN, DCL), or polymers with addition of inorganic agents
are more resistant than conventional polymethylmetacrylate
(PMMA) teeth. In a recent abrasion wear resistance test,
cross-linked teeth or teeth with addition of an inorganic layer
presented greater abrasion wear resistance than conventional
PMMA teeth16. Other clinical studies, however, did not find
significant differences among the wear presented by
conventional PMMA teeth and improved acrylic teeth (DCL,
IPN)5,8,10,12.
Based on the findings of Ghazal, et al.5 (2008), the test
performed in this study correspond to an approach of two-
body wear with direct contact between the artificial teeth
tested and the antagonist, which produces a mixed wear of
adhesion, attrition and fatigue. Some authors have stated
that this condition is especially important when considering
complete dentures with a bilaterally balanced occlusion6,15.
Additionally, in a 2-body wear test only direct interactions
between surfaces of sample and antagonist cause a substance
loss15.
In the present study, the group PO (double cross-linking
[DCL] polymethylmetacrylate) presented the smallest wear
mean values, for both metallic and composite antagonists.
The group OR (polymer with inorganic filling) presented
the highest wear mean values against metallic antagonists
among all other groups tested. However, it presented small
wear mean values against composite antagonists, similar to
the best results obtained by the other groups, which suggests
a different type of interaction, possibly justified by the fact
that both types of artificial teeth are based on the same
polymer type. Brigagão, et al.2 (2005) obtained smaller
values of weight and height loss for PO teeth. However,
these authors did not obtain enough wear on the tested
specimens, and no significant differences were observed
among the groups, using 200,000 cycles, which
corresponded to 1 year of clinical function14, with 400 g
load.
Possibly due to the load used in this study, which was
low (5 N), no wear was measured in the antagonists. Because
the rough surface characteristics (75 m, accordingly to the
DIN method of the ISO/TS 14569-2 standard) just a mark
was visible. The vertical substance loss measured in this
study, as a consequence of the sliding contact of a buccal
cusp of artificial teeth and the antagonist tablets, represents
the abraded area of the teeth. Each artificial teeth used in
this study has a particular cusp shape, and the contact area
increased as the abrasion test was performed. In order to
avoid higher influence of this increased contact area, the
tests performed were limited to simulate a 120-day use of
the teeth. In addition, the cusp shape in this study was in
accordance with the sample dimensions described in the ISO/
TS 14569-2 standard (Dental Materials – Guidance on
testing of wear – Part 2: Wear by two – and/or three-body
contact, 2001) under the Freiburg Method. However, this is
a limitation of the method used3. Other evaluations, with
higher loads, must be performed to determine the effects on
both the artificial teeth and antagonist materials. Reis, et
al.13 (2008) used a canine tooth to test the in vitro wear
resistance for three types of PMMA artificial teeth in a
similar way, and observed that tested PMMA denture teeth
have significantly different wear resistance against abraded
ceramic. The highest values were found for high-strength
PMMA teeth than conventional PMMA teeth.
The findings of present in vitro study are important for
the comparison of the abrasion wear resistance of different
commercially available artificial teeth against different types
of antagonists. However, clinical trials with these materials
for longer periods are still necessary. In addition, new studies
should be accomplished to establish the wear resistance of
artificial teeth when they are used opposing materials with
the same wear characteristics.
CONCLUSIONS
Based on the methodology applied to this study,
considering the inherent limitations and the obtained results,
it may be concluded that the antagonist material present on
(or planed for) a clinical rehabilitation is a factor of major
importance to be considered for the choice of the artificial
teeth to be used in the prosthesis. OR was the group that
presented the greatest result variance regarding the abrasion
wear resistance; it also presented the worst result opposed
to metallic antagonist (10.45 ± 1.42 m), and a result similar
MELLO P C, COPPEDÊ A R, MACEDO A P, MATTOS M da G C de, RODRIGUES R C S, RIBEIRO R F
455
to the best ones opposed to composite antagonists (2.77 ±
0.69 m). The group PO presented the smallest wear mean
values, both for metallic (1.70 ± 0.42 m) and composite
(2.30 ± 0.91 m) antagonists. In the light of the obtained
results, dentist’s decision to indicate any of the artificial teeth
tested in this study can be made based on the analysis of
important characteristics in determining its functionality and
esthetics, allied to the cost of the material.
ACKNOWLEDGMENTS
The authors thank to Mr. Luiz Sérgio Soares and Mr.
Paulo Donato Frighetto for their technical assistance, as well
as the manufacturers for donation of artificial teeth.
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... It is known that this material does not chemically combine with PMMA (it cannot be successfully subjected to the silanization process). Similar conclusions regarding the increased resistance to abrasion and the hardness of methacrylic teeth with inorganic fillers were also drawn by Mello (2009) [4]. The compressive strength of neat PMMA is dependent on the curing conditions thereof but is often below 100 MPa [5]. ...
... It is known that this material does not chemically combine with PMMA (it cannot be successfully subjected to the silanization process). Similar conclusions regarding the increased resistance to abrasion and the hardness of methacrylic teeth with inorganic fillers were also drawn by Mello (2009) [4]. The compressive strength of neat PMMA is dependent on the curing conditions thereof but is often below 100 MPa [5]. ...
... It is known that this material does not chemically combine with PMMA (it cannot be successfully subjected to the silanization process). Similar conclusions regarding the increased resistance to abrasion and the hardness of methacrylic teeth with inorganic fillers were also drawn by Mello (2009) [4]. ...
Article
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This study was aimed at investigating poly(methyl methacrylate) (PMMA), modified with a silanized feldspar filler at 10 wt.% and 30 wt.%, as a dental material system for the production of prosthetic teeth. Samples of this composite were subjected to a compressive strength test, three-layer methacrylic teeth were fabricated with the said materials, and their connection to a denture plate was examined. The biocompatibility of the materials was assessed via cytotoxicity tests on human gingival fibroblasts (HGFs) and Chinese hamster ovarian cells (CHO-K1). The addition of feldspar significantly improved the material's compressive strength, with neat PMMA reaching 107 MPa, and the addition of 30% feldspar raising it up to 159 MPa. As observed, composite teeth (cervical part made of neat PMMA, dentin with 10 wt.%, and enamel with 30 wt.% of feldspar) had good adhesion to the denture plate. Neither of the tested materials revealed any cytotoxic effects. In the case of hamster fibroblasts, increased cell viability was observed, with only morphological changes being noticed. Samples containing 10% or 30% of inorganic filler were determined to be safe for treated cells. The use of silanized feldspar to fabricate composite teeth increased their hardness, which is of significant clinical importance for the duration of use of non-retained dentures.
... An influence of the antagonist material on the two-body wear has been reported in several investigations using antagonists made of different ceramics [25,26], resin-based materials [7,[27][28][29], steel [27,[30][31][32], steatite [3,33,34] or human enamel [7,15,25,31,35]. The significance of this parameter is underlined by silicate ceramic substrates exhibiting approximately fourfold material losses using steel antagonists compared to resin composite antagonists [27]. ...
... An influence of the antagonist material on the two-body wear has been reported in several investigations using antagonists made of different ceramics [25,26], resin-based materials [7,[27][28][29], steel [27,[30][31][32], steatite [3,33,34] or human enamel [7,15,25,31,35]. The significance of this parameter is underlined by silicate ceramic substrates exhibiting approximately fourfold material losses using steel antagonists compared to resin composite antagonists [27]. ...
... An influence of the antagonist material on the two-body wear has been reported in several investigations using antagonists made of different ceramics [25,26], resin-based materials [7,[27][28][29], steel [27,[30][31][32], steatite [3,33,34] or human enamel [7,15,25,31,35]. The significance of this parameter is underlined by silicate ceramic substrates exhibiting approximately fourfold material losses using steel antagonists compared to resin composite antagonists [27]. Ceramic antagonists, on the other hand, cause higher material losses compared to enamel [15]. ...
Article
Objectives To investigate the impact of crown geometry, crown/abutment/antagonist material and thermal loading on the two-body wear of dental materials caused by chewing simulation. Materials and methods For the crown geometry, crowns (polymethylmethacrylate (PMMA), polyetheretherketone (PEEK) and silicate ceramic (SiO2)) were milled with a flat, steep, or medium cusp inclination (CINC). For the crown/abutment material, crowns (PMMA, PEEK and SiO2) were combined with PMMA, polymer-infiltrated-ceramic-network (PICN), cobalt-chrome alloy (CoCr) and natural teeth (ENAM) abutments. For the antagonist material, antagonists were fabricated from PICN, CAD/CAM resin composite (RECO), steatite (STEA), steel (STL) and ENAM and tested against flat specimens (substrates) made of veneering ceramic (VC). For thermal loading, the duration (30 s, 60 s, 120 s) and presence of temperature changes (37 °C versus 5 °C/55 °C) was varied. Material losses were determined by matching scanned specimens before and after aging (400,000 chewing cycles, 50 N, 1.3 Hz). Martens parameters were determined for the antagonists/substrates. Data were analyzed using Kolmogorov-Smirnov-test, Kruskal-Wallis H, Scheffé-Post-Hoc-tests, pairwise comparisons, Bonferroni correction, one-way ANOVA, Mann-Whitney-U and Spearman rho. Results PMMA crowns presented the highest and PEEK the lowest material losses. Flat CINC showed the lowest material losses for PEEK and SiO2 crowns. CoCr and ENAM abutments presented material losses in the same range. Antagonist and cumulative material losses for RECO and ENAM were similar. Thermal loading did not influence material losses. Significance Crown geometry influences the crown and antagonists wear, with an increased cusp inclination entailing increased wear. For in vitro set-ups, CoCr abutments and RECO antagonists present valid alternatives to natural teeth. For polymers, in vitro chewing simulations may be performed at a constant temperature (37 °C).
... Surface loss is usually observed more on posterior teeth than on the anterior teeth [3]. Teeth wear is of great concern to both patients and clinicians because the altered teeth morphology can result in loss of occlusal vertical dimension, compromised masticatory efficiency, fatigue of the muscles of mastication and patient discomfort, as well as affecting aesthetics [7]. Ultimately dentures are considered inadequate when teeth wear compromises their stability and retention, as it plays a crucial role in occlusal stability on the preservation of crestal ridges. ...
... Along with the addition of one hand search article [24], a total of 42 studies were included in the review ( Figure 1). From the 42 included studies, 11 studies were conducted in vivo [3,[24][25][26][27][28][29][30][31][32][33], and 31 were in vitro studies [1,7,[9][10][11][12][13]16,25,. ...
Article
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The purpose of this systematic review was to identify the different methods used to measure artificial teeth wear and to determine which denture teeth (or which combination of tooth types) have better wear resistance. The focused patient, intervention, comparison, and outcome (PICO) question for this review was “which available denture teeth or combination of teeth have higher wear resistance?” The method of testing and measuring the artificial teeth wear was also evaluated as a secondary outcome. We searched OVID Medline, PubMed and SCOPUS using the following terms (MeSH words) with any synonyms and closed terms: “wear”, “denture teeth”, “denture tooth”, or “artificial tooth”, “tooth wear”, or combination of “denture tooth wear”. Database searches were limited to the English language and studies published between years 1997 and 2021. Further hand searches were carried out of studies identified from the bibliographies of relevant articles. The electronic data base search identified 293 articles of which 213 were eliminated after removing duplicates and screening the titles of the articles. A further 31 articles were eliminated upon application of the exclusion criterion and full text reading because they were either not in the English language or were review articles. Only 41 articles met the inclusion criterion; along with addition of one hand search article, a total of 42 articles were included in the review. The studies showed that rate of denture teeth wear is influenced by factors such as the material and composition of the artificial teeth, the denture tooth antagonist, the tooth being replaced, patient’s age and sex, the type of removable prosthesis and the amount of the superficial layer removed during occlusal adjustments. The testing parameters were inconsistent across all studies. In conclusion, artificial teeth of same material should be used as antagonists where possible, and the superficial outer layer of the teeth must be preserved as much as possible during occlusal adjustments to enhance wear resistance. Denture teeth should be selected taking into consideration the tooth being replaced, the age and sex of the patient, and the type of prosthesis. Incorporation of nano fillers into acrylic resin teeth does not increase wear resistance; therefore, there is no evidence to favour the use of nano-filled composite teeth over micro-filled or conventional acrylic resin teeth.
... Denture teeth are currently made of either methacrylate-based resins (acrylic resin) or porcelain, but acrylic teeth have nearly eliminated porcelain teeth from the market [1] due to a number of advantages, including their chemical bonding to the denture base [2,3], lower susceptibility to fracture [4,5] and decreased clicking [6,7]. Acrylic resin tooth wear is a serious complication during denture service and can change the vertical dimension of dentures. ...
... This process harms the denture and exerts an impact on facial aesthetics and the function of the masticatory muscles, resulting in less efficient mastication. This can result in temporomandibular disorders, digestive disturbances and decreased patient comfort [6][7][8][9]. Efforts were made to enhance the wear resistance of the acrylic resin denture teeth, such as the formation of cross-linked polymer teeth (interpenetrated polymer network) [8,9]. Another possible solution is to add nanofillers to enhance mechanical properties. ...
Article
Full-text available
The wear of acrylic denture teeth is a serious problem that can change the vertical dimensions of dentures. This study evaluates the effect of adding salinized nano ZrO2 particles on the microstructure, hardness, and wear resistance of acrylic denture teeth. Heat polymerizing polymethyl methacrylate resin was mixed with salinized ZrO2 at concentrations of 5 wt% and 10 wt%. Acrylic resin specimens without filler addition were used as a control group. SEM/EDS analyses were performed and the Vickers’ hardness was evaluated. Two-body wear testing was performed using a chewing simulator with a human enamel antagonist. After subjecting the samples to 37,500 cycles, both height loss and weight loss were used to evaluate the wear behavior. The microstructural investigation of the reinforced-denture teeth indicates sound nanocomposite preparation using the applied regime without porosity or macro defects. The addition of zirconium oxide nanofillers to PMMA at both 5% and 10% increased the microhardness, with values of up to 49.7 HV. The wear mechanism in the acrylic base material without nanoparticle addition was found to be fatigue wear; a high density of microcracks were found. The addition of 5 wt% ZrO2 improved the wear resistance. Increasing the nanoparticles to 10 wt% ZrO2 further improved the wear resistance, with no microcracks found.
... Recent studies have employed 3D evaluation methods to assess the wear behavior of dental materials [39][40][41]. In the present study, wear measurement involved 3D digital scans taken before and after wear testing, with 2D vertical loss (mm) and 3D volume loss (mm 3 ) calculated by overlaying and subtracting the two 3D models. ...
Article
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Background and Objectives: Advances in dental materials and CAD-CAM technology have expanded crown options in primary teeth due to their improved appearance and mechanical properties. Thus, this study aimed to assess the enamel wear and fracture resistance of prefabricated, milled, and 3D-printed esthetic pediatric crowns. Materials and Methods: The study involved 60 extracted maxillary second primary molars and 60 3D-printed resin dies, divided into six groups based on different crown materials (n = 10): prefabricated zirconia, prefabricated composite, milled composite, milled resin matrix ceramic, milled PEEK, and 3D-printed resin. Prefabricated crowns were selected after the preparation of the typodont mandibular second primary molar tooth, while milled and 3D-printed crowns were custom produced. The specimens underwent mechanical loading of 50 N at 1.6 Hz for 250,000 cycles with simultaneous thermal cycling. The 3D and 2D wear amounts were evaluated by scanning the specimens before and after aging. Then, the fracture resistance and failure types of the restorations were recorded. Results: The results showed that the milled PEEK group had superior fracture resistance compared to the other groups, while prefabricated zirconia crown group had the lowest value. Milled resin matrix ceramic crown group displayed the lowest 3D wear volume, while 3D-printed crown group showed the highest 2D wear. Conclusions: The restorative material type did not have a significant effect on the wear of primary tooth enamel. The fracture resistance of the tested materials differed according to the material type. Although the milled PEEK group showed the highest fracture resistance, all tested materials can withstand chewing forces in children.
... Entire dentures (47.7%), ICFDP (19.6%), and partial dentures (20%) are the most common problems [21]. The PEKK architecture is far less traumatic on the graft and mucosa than tensile stress. ...
... Changes in properties, such as wear resistance, promote modifications in the vertical dimension of occlusion (VDO), reduced masticatory efficiency, impaired intermaxillary relationship, and altered muscle function which can lead to temporomandibular dysfunction (TMD), changes in aesthetics, discomfort, risk of fracture and need for prosthesis replacement. Wear is a property that should be evaluated with caution, it can be caused by inadequate brushing, excessive force when chewing, bruxism and clenching, consumption of acidic foods and drinks, improper use of dentures, the length of time they have been in use and the type of material used to make them [1][2][3][4][5]. ...
Article
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Wear resistance is one of the properties that must be considered for maintaining the long-term functionality of artificial teeth in dental prostheses. This property can be altered by the method of tooth fabrication, the material, the chewing force, and the relationship to the antagonist tooth. This systematic review evaluated the wear resistance of artificial teeth obtained by the additive manufacturing method and aims to answer the question, "Do artificial teeth for dental prostheses obtained by additive manufacturing show wear resistance similar to prefabricated ones?" The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Checklist guidelines were followed with a customized search in Scopus, PubMed/Medline, Embase, Science Direct, and Google Scholar databases on August 30, 2023. The inclusion criteria were artificial teeth for dental prostheses in acrylic resin by additive manufacturing and comparing the wear resistance with conventional prefabricated teeth, in vitro and English studies, without time restriction. And excluded if 1) do not make artificial teeth by additive manufacturing or that were metal or ceramic teeth; 2) clinical trials, animal studies, review articles, case reports, letters to the editor, short communication, book chapters; 3) another language that is not English. The selection was in two steps, reading the titles and abstracts, followed by reading the selected studies in full. The risk of bias analysis was performed with the adaptation of the quasi-experimental studies tool by Joanna Briggs Institute. Four hundred and twelve articles were found in the databases, after the selection steps and application of eligibility criteria, 6 articles were included for qualitative data analysis and presented low risk of bias. For teeth obtained by additive manufacturing, 2 studies reported lower wear resistance, 2 studies had higher resistance, and 2 similar compared to prefabricated ones. Additive manufactured teeth compared to prefabricated teeth show influences on wear resistance due to differences in material composition, relationship to the antagonist's tooth, applied force, chewing cycles, and processing methods.
... e test was repeated 10000 times, clinically simulating approximately one month of chewing function. Antagonist was attached to the upper member and prepared from natural teeth [23,24]. In the current study, wear was measured by evaluating surface roughness before and after the wear procedure (Δ Ra) where the parameters of the wear test are mentioned in Table 3 [25,26]. ...
Article
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Objective: This study aimed to investigate the effects of nanoparticles (zirconium dioxide (ZrO2), titanium dioxide (TiO2), and silicon dioxide (SiO2)) on the flexural strength, impact strength, hardness, and wear resistance of the acrylic resin denture base material. Materials and methods: Acrylic resin specimens were fabricated in dimensions according to American Dental Association (ADA) specifications per test. Specimens were divided according to nanofiller into four groups; unmodified as control, ZrO2 (Z), TiO2, (T), and SiO2 (S) groups. Each one was subdivided into two subgroups according to nanoparticle concentrations; 3% and 7% (Z3, Z7, T3, T7, S3, and S7). A 3-point bending test, Charpy impact test, and Vickers hardness test were used for flexural strength, impact strength, and hardness measurements, respectively. Wear resistance was measured by the differences in surface roughness of tested specimens before and after the wear test. A scanning electron microscope was used to assess nanoparticle specifications and distributions and for fracture surfaces analysis. ANOVA, Bonferroni's post hoc test, and the Kruskal-Wallis test were applied for data analysis (α = 0.05). Results: Regarding the flexural and impact strength, there was a statistically remarkable increase for all tested groups compared with the control group, except for the T7 and S7 groups (P value <0.001, effect size = 0.893) and (P value <0.001, effect size = 0.759), respectively. There was a statistically significant improvement in the hardness of all tested groups compared with the control group (P value <0.001, effect size = 0.67) except T3 and S3. Regarding wear, a statistically significant enhancement was noticed in the wear resistance of all tested groups (P value <0.001, effect size = 0.685), except for the T7 and S7 groups. Conclusion: The flexural strength, impact strength, and wear resistance improved with both concentrations of ZrO2 and low TiO2 and SiO2 concentrations. The hardness increased with both concentrations of ZrO2 and high TiO2 and SiO2 concentrations.
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Purpose This study aimed to assess the 3-body wear of prefabricated and 3D-printed artificial denture teeth. Materials and methods Four groups of artificial teeth were used; 3D-printed polymethylmethacrylate (PMMA) teeth (PR) and 3 prefabricated commercially available denture teeth: PMMA (Gnathostar, GN), PMMA (SR Orthotyp PE, SR), and Nanohybrid composite (SR Phonares NHC, PH). The 3-body wear test was performed using a steatite ceramic antagonist in a chewing simulator with 750,000 cycles, temperature 23 ± 2 ˚C, and force of 50 N. The abrasive medium was composed of ground millet seeds and white rice mixed with distilled water. The teeth were 3D-scanned before and after the wear test. The 3D images were assessed for teeth wear by measuring the volumetric (3D wear) and the vertical (2D wear) substance loss. The one-way analysis of variance followed by Tukey post hoc test was used to statistically obtain the data analysis. Results Maximum 3D wear was observed in the PR (51.05 ± 4.53 mm³), followed by GN (20.22 ± 6.29 mm³) and SR (12.12 ± 6.29 mm³) artificial teeth. Minimum wear occurred in the PH teeth (6.24 ± 0.87 mm³). The analytical differences amongst the groups were statistically significant (P < .05) except between PH and SR teeth. For 2D wear measurement, the maximum was seen in the GN teeth (6.29 ± 1.64 mm), followed by PR (5.04 ± 0.83 mm) and then SR (4.53 ± 0.87 mm). The PH teeth (3.09 ± 0.68 mm) again showed minimum wear. Statistically, amongst the groups, the major observable differences (P < .05) were between PH and GN, PH and PR, and SR and GN. Conclusions Composite resin teeth had a greater wear resistance than acrylic resin teeth and 3D-printed resin teeth, both of which were comparable. Due to the advancement of digital workflows, manufacturers should devote effort to enhancing 3D-printed teeth.
Article
A common complication with the use of acrylic resin denture teeth is wear of the occlusal surfaces. Modifying the occlusal surfaces with gold onlays has been suggested to combat this phenomenon. This clinical report describes the use of zirconia as an alternative material on a patient with increased tendencies for occlusal wear. The advantages of using zirconia include wear resistance, decreased cost, and straightforward fabrication.
Article
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The wear of artificial resin teeth used in prosthetic rehabilitation treatment is of great concern to the dentist, since wear changes the occlusal vertical dimension (OVD) and may provoke cranio-mandibular disturbance, decrease masticatory efficiency, increase the discomfort for the patient and alter esthetics. Thus, one of the most important physical properties of artificial teeth is their abrasion resistance and the ability to maintain the occlusal relation of the patient stable. To evaluate the rates of wear of eight commercially available brands of artificial resin teeth, forty-eight samples were prepared from 8 different brands, totaling 8 groups each with six elements. The samples were evaluated by a gravimetric method, and analyzed by measuring the difference between the initial and final weights following the experiment. Obtained values were submitted to variance analysis and Tukey's test (p<0.05). Statistic analysis revealed a difference between Artplus, Biolux, Duratone, Trilux, Trubyte Biotone and Vipi Dent Plus brands and the SR Orthosit teeth. Teeth of Myerson brand did not show any significant difference for any of the brands tested, presenting results with intermediate values (p<0.05). Artplus, Biolux, Duratone, Trilux, Trubyte Biotone and Vipi Dent Plus teeth brands presented higher wear values, while the SR Orthosit teeth brand demonstrated lower wear values and was, therefore, the best brand of tooth among those evaluated.
Article
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The wear resistance of denture teeth is important to the longevity of removable prostheses of edentulous patients. The ability of denture teeth to maintain a stable occlusal relationship over time may be influenced by this property. The purpose of this in vitro study was to evaluate the wear resistance of polymethyl methacrylate (PMMA) denture teeth based on their chemical composition when opposed by a ceramic antagonist. The maxillary canines (n=10) of 3 PMMA denture teeth (Trubyte Biotone, cross-linked PMMA; Trilux, highly cross-linked IPN (interpenetrating polymer network)-PMMA; and Vivodent, highly cross-linked PMMA) were secured in an in vitro 2-body wear-testing apparatus that produced sliding contact of the specimens (4.5 cycles/s, sliding distance of 20 mm, under 37 degrees C running water) against glazed or airborne particle abraded ceramic. Wear resistance was measured as height loss (mm) under 300 g (sliding force) after 100,000 cycles, using a digital measuring microscope. Mean values were analyzed by 2-way ANOVA and Tukey's test (a=0.05). The wear of Trubyte Biotone (0.93 +/- 0.14 mm) was significantly higher than that of both other types of teeth tested against abraded ceramic (p<0.05). The Vivodent tooth (0.64 +/- 0.17 mm) exhibited the best wear resistance among the denture teeth tested against airborne particle abraded ceramic. There were no statistically significant differences (p>0.05) in wear among the 3 denture teeth evaluated against glazed ceramic. Trilux and Vivodent teeth tested against either glazed or airborne particle abraded ceramic did not differ significantly from each other (p<0.05). All teeth showed significantly more wear against airborne particle abraded ceramic than against glazed ceramic (p<0.05). In conclusion, the three types of PMMA denture teeth presented significantly different wear resistance against the abraded ceramic. The high-strength PMMA denture teeth were more wear-resistant than the conventional PMMA denture tooth.
Article
One of the most important physical properties of artificial teeth used in the restoration of the edentulous patient is wear resistance, and the ability of these teeth to maintain a stable occlusal relationship over time. This study compared the in vitro wear of four different resin denture teeth against human enamel. Five denture tooth samples opposing five enamel abraders were positioned in a mechanical wear testing device for two 5,000 cycle wear periods (total of 10,000 cycles) under a 13.4 N load. All tests were conducted in human saliva, and the wear was measured at the end of each test period. The wear of the Classic and Kenson acrylic resin denture teeth was much greater than the DB Plus and MLI composite teeth after 10,000 cycles. The wear of the KENSON denture tooth was also greater than the Classic tooth. No wear differences were found between the two composite teeth. The wear of DB Plus and MLI resin denture teeth was approximately 50% less than the wear of Classic and Kenson teeth when opposed by human enamel.
Article
Excessive wear of artificial resin teeth has been a concern to both the patient and the dentist because of unfavorable associated sequelae. The search for a more wear resistant resin tooth material resulted in the development of modified resin teeth that displayed acceptable wear resistance. This study compared clinical wear of a new modified resin tooth material with two other commercially available modified resin materials over a period of 36 months. Differences in wear by gender, cuspal anatomy, arch, individual tooth type, and chewing side preference were also evaluated. A total of 67 patients were randomized into one of three treatment groups in this double-blind study; group 1, Ivoclar-Vivodent and Orthotyp; group 2, Dentsply-Trublend SLM; and group 3, Dentsply-Bioblend IPN. Tooth wear was determined by measuring vertical heights of contacting points at baseline and 36 months with a computerized coordinate measuring machine and computer-controlled positioning stages. Measurements were completed at 36 months for 55 patients who remained in the study. Repeated measures analysis of variance revealed no significant difference in total wear by gender or tooth material at 36 months. There was also no significant difference by chewing side preference or cuspal anatomy. However, there was a significant difference in individual tooth wear (canine, premolar, molar) and by arch. New modified resin teeth have displayed clinically acceptable wear resistance for most patients.
Article
Wear resistance is one of the most important physical properties of artificial resin teeth, and its dependence on the antagonist material has not been clearly established. The purpose of this in vitro study was to investigate the wear resistance of representative artificial resin teeth in relation to antagonist material. Twenty-four standardized specimens were prepared for each of 8 tooth types representative of anterior and posterior artificial acrylic and composite resin teeth (Gnathostar, SR Orthosit PE, Condyloform II NFC, SR Postaris DCL, SR Vivodent PE, VITA Physiodens, SR Antaris DCL, Bioplus), for a total of 192 specimens. Each specimen was prepared to a diameter of 5 mm and a thickness of 2 mm on the buccal/facial tooth surfaces. The specimens were then polished and subjected to simulated mastication (50 N, 1.2 x 10(5) cycles, 1.2 Hz) using a pin-on-block design and additional thermocycling (600 cycles, 5/55 degrees C, 2 min/cycle). Three antagonists (artificial resin teeth, steel, steatite) were prepared, and 8 specimens per tooth type were tested for each antagonist. Vertical substance and volume loss were analyzed using cast replicas and an optical 3-dimensional (3-D) surface profilometer, as well as scanning electron microscopy. Data were analyzed using 2- and 1-way ANOVA and the Games-Howell test (alpha=.05). For both vertical substance and volume loss, significant differences were found for the various antagonists. Lowest overall mean values (SD) for vertical substance and volume loss were measured for artificial tooth antagonists (26 (10) microm to 95 (46) microm, 1.5 (1.5) microm(3) to 10.5 (9) microm(3)), and the highest values were measured for steatite antagonists (95 (23) microm to 723 (168) microm, 8 (4) microm(3) to 245 (109) microm(3)). Intermediate mean values (SD) for vertical substance and volume loss were measured for steel antagonists (118 (88) microm to 205 (120) microm, 9 (7) microm(3) to 28 (24) microm(3)). Using artificial teeth and steel antagonists, few significant differences in wear resistance were found between the various resin teeth. In contrast, significant differences were observed with steatite antagonists. The use of steatite antagonists allowed for significantly better differentiation of wear behavior between various artificial teeth than the use of artificial resin teeth or steel antagonists.
Article
This investigation compared the wear resistance of three "improved" resin posterior denture tooth formulations with two conventional products on a mechanical toothbrush abrasion machine. The ability of the teeth to resist this type of abrasion was evaluated by determination of the weight loss during 339 hours of brushing with firm nylon bristle toothbrushes. All brands exhibited negligible loss, with the conventional brands performing better than the "improved" formulations. © 1992 The Editorial Council of The Journal of Prosthetic Dentistry.
Article
This study compared in vivo wear of a new artificial tooth material with that of existing artificial tooth materials. Artificial tooth wear was determined by measuring height changes of selected points on contacting tooth surfaces in patients with complete dentures during a 12-month period. These results are part of an ongoing 3-year clinical study. A total of 67 patients were randomized to one of three treatment groups in this double-blind study. Group 1 received dentures with existing artificial tooth materials. Group 2 received dentures that contained teeth with the new experimental material. Group 3 received dentures with Bioform IPN resin teeth (Dentsply International Inc., York, Pa). A computerized coordinate measuring machine and computer-controlled X-Y positioning stages were used for this study. Tooth wear was determined by measuring vertical heights of contacting points from baseline points at each of two time intervals. The calculation of wear was made by comparing the differences in height at the beginning of the experiment with those measured at each time interval. A repeated measures analysis of variance (ANOVA) was used to test the difference in mean wear among the three groups from baseline to 6 months and from 6 to 12 months. Group differences in total wear at 12 months were also tested. The ANOVA results revealed no statistically significant differences in the wear among the three types of denture teeth at the 6- or 12-month time intervals or at 12 months (p > 0.05). The average total wear value at 12 months was 90 microns. Group 1 averaged 102 microns of wear, group 2 averaged 88 microns of wear, and group 3 averaged 76 microns of wear.
Article
Clinical abrasion of denture teeth has certain implications when dentures are worn in excess of the average useful lifetime. The purpose of this study was to evaluate clinical denture tooth wear over a period of 3 years. The wear of six commercially available denture teeth (Premierdent, Acrotone, vitapan, Rx1, Duravite, and Ivoclar Orthosit) and a seventh combination of teeth was compared. Seventy patients with complete dentures were divided into seven groups of 10 each to form the study population. There were no significant differences among the commercial denture teeth. Porcelain/Vitapan teeth exhibited the highest amount of abrasion. Significant wear was also measured between the Ivoclar Orthosit and Porcelain/Vitapan teeth.
Article
This in vitro study evaluated the wear resistance of a high-strength resin posterior denture tooth against eight opposing dental materials. The tooth specimen was cusp shaped and the opposing materials were formed as a 10 x 10 x 5 mm plate. All material combinations were tested using a machine designed to produce sliding contact 20 x 10(4) times at 60 cycles per minute and a 4-mm sliding distance per stroke in the buccolingual direction under a load of 1 kg. Wear analysis was measured as the total height loss of each material combination and the volume loss of each material. Wear against human enamel was evaluated as a control. The least loss was observed opposing a gold-silver-palladium-copper alloy, and the greatest loss was observed opposing porcelain. The volume loss of high-strength resin against gold-silver-palladium-copper alloy was as small as that against human enamel. High-strength resin wear was more significant against castable ceramics and porcelain. The volume losses of high-strength resin against high-strength resin, polycarbonate, or cobalt-chromium alloy were significantly larger than those against polyethersulfone, poly(methyl methacrylate), gold-silver-palladium-copper alloy, or human enamel. These findings suggest that the were resistance of high-strength resin is influenced considerably by opposing dental materials, and that the best combination was high-strength resin-gold-silver-palladium-copper alloy, and the poorest combination was high-strength resin-porcelain.