ArticlePDF Available

Wear of Enamel Opposing Zirconia and Lithium Disilicate after Adjustment, Polishing and Glazing

DOI:10.1016/j.jdent.2014.09.008
Authors:
Nathaniel Lawson at University of Alabama at Birmingham
Nathaniel Lawson
S. Janyavula at Dentsply Sirona
S. Janyavula
Sarah Syklawer at University of Michigan
Sarah Syklawer
Edward Mclaren at University of California, Los Angeles
Edward Mclaren
Show all 5 authorsHide
Download full-text PDF
Read full-text
Download citation

Abstract and Figures

Objectives: To compare the wear and opposing enamel wear of adjusted (A); adjusted and polished (AP); and adjusted and glazed (AG) zirconia and lithium disilicate. Methods: Specimens (n=8) were prepared of lithium disilicate (A, AP, and AG), zirconia (A, AP, and AG), veneering porcelain, and enamel (control). Surface roughness was measured for each ceramic. In vitro wear was conducted in the UAB-chewing simulator (10 N vertical load/2mm slide/20 cycles/min) with lubricant (33% glycerin) for 400,000 cycles. Isolated cusps of extracted molars were used as antagonists. Scans of the cusps and ceramics were taken at baseline and 400,000 cycles with a non-contact profilometer and super-imposed to determine wear. Data were analyzed with ANOVA and Tukey-Kramer post hoc tests (alpha=0.05). Results: A and AP zirconia showed no detectable signs of wear, and the veneering porcelain demonstrated the most wear. All other ceramics showed significantly less volumetric loss than the veneering porcelain, comparable to enamel-enamel wear. Veneering porcelain produced the most opposing enamel wear (2.15 ± 0.58 mm(3)). AP lithium disilicate and zirconia showed the least amount of enamel wear (0.36 ± 0.09 mm(3) and 0.33 ± 0.11 mm(3) respectively). AG lithium disilicate had statistically similar enamel wear as AP lithium disilicate, but A lithium disilicate had more enamel wear. A and AG zirconia had more enamel wear than AP zirconia. No statistically significant difference was seen between the enamel-enamel group and any other group except the veneering porcelain. Conclusions: Zirconia has less wear than lithium disilicate. Wear of enamel opposing adjusted lithium disilicate and zirconia decreased following polishing. Clinical significance: Zirconia experiences less and lithium disilicate experiences equivalent occlusal wear as natural enamel. It is preferable to polish zirconia and lithium disilicate after adjustment to make them wear compatible with enamel. Veneering of zirconia and lithium disilicate should be avoided in areas of occlusal contact to prevent enamel wear.
Figures - uploaded by S. Janyavula
Author content
All figure content in this area was uploaded by S. Janyavula
Content may be subject to copyright.
Content uploaded by S. Janyavula
Author content
All content in this area was uploaded by S. Janyavula on May 12, 2019
Content may be subject to copyright.
Wear
of
enamel
opposing
zirconia
and
lithium
disilicate
after
adjustment,
polishing
and
glazing
§
Nathaniel
C.
Lawson
a,
*,
Sridhar
Janyavula
a
,
Sarah
Syklawer
a
,
Edward
A.
McLaren
b
,
John
O.
Burgess
a
a
University
of
Alabama
at
Birmingham
School
of
Dentistry,
Clinical
and
Community
Sciences,
Division
of
Biomaterials,
1919
7th
Avenue
South,
Birmingham,
AL
35205,
USA
b
University
of
California
Los
Angeles
School
of
Dentistry,
Center
for
Esthetic
Dentistry,
CHS
23-010,
Los
Angeles,
CA
90095-1668,
USA
j
o
u
r
n
a
l
o
f
d
e
n
t
i
s
t
r
y
x
x
x
(
2
0
1
4
)
x
x
x
–
x
x
x
a
r
t
i
c
l
e
i
n
f
o
Article
history:
Received
23
June
2014
Received
in
revised
form
19
August
2014
Accepted
15
September
2014
Available
online
xxx
Keywords:
Zirconia
Lithium
disilicate
Porcelain
Enamel
Wear
Glaze
a
b
s
t
r
a
c
t
Objectives:
To
compare
the
wear
and
opposing
enamel
wear
of
adjusted
(A);
adjusted
and
polished
(AP);
and
adjusted
and
glazed
(AG)
zirconia
and
lithium
disilicate.
Methods:
Specimens
(n
=
8)
were
prepared
of
lithium
disilicate
(A,
AP,
and
AG),
zirconia
(A,
AP,
and
AG),
veneering
porcelain,
and
enamel
(control).
Surface
roughness
was
measured
for
each
ceramic.
In
vitro
wear
was
conducted
in
the
UAB-chewing
simulator
(10
N
vertical
load/2
mm
slide/20
cycles/min)
with
lubricant
(33%
glycerin)
for
400,000
cycles.
Isolated
cusps
of
extracted
molars
were
used
as
antagonists.
Scans
of
the
cusps
and
ceramics
were
taken
at
baseline
and
400,000
cycles
with
a
non-
contact
profilometer
and
super-imposed
to
determine
wear.
Data
were
analyzed
with
ANOVA
and
Tukey–Kramer
post
hoc
tests
(alpha
=
0.05).
Results:
A
and
AP
zirconia
showed
no
detectable
signs
of
wear,
and
the
veneering
porcelain
demonstrated
the
most
wear.
All
other
ceramics
showed
significantly
less
volumetric
loss
than
the
veneering
porcelain,
comparable
to
enamel–enamel
wear.
Veneering
porcelain
produced
the
most
opposing
enamel
wear
(2.15
0.58
mm
3
).
AP
lithium
disilicate
and
zirconia
showed
the
least
amount
of
enamel
wear
(0.36
0.09
mm
3
and
0.33
0.11
mm
3
respectively).
AG
lithium
disilicate
had
statistically
similar
enamel
wear
as
AP
lithium
disilicate,
but
A
lithium
disilicate
had
more
enamel
wear.
A
and
AG
zirconia
had
more
enamel
wear
than
AP
zirconia.
No
statistically
significant
difference
was
seen
between
the
enamel–enamel
group
and
any
other
group
except
the
veneering
porcelain.
Conclusions:
Zirconia
has
less
wear
than
lithium
disilicate.
Wear
of
enamel
opposing
adjusted
lithium
disilicate
and
zirconia
decreased
following
polishing.
Clinical
significance:
Zirconia
experiences
less
and
lithium
disilicate
experiences
equivalent
occlusal
wear
as
natural
enamel.
It
is
preferable
to
polish
zirconia
and
lithium
disilicate
after
adjustment
to
make
them
wear
compatible
with
enamel.
Veneering
of
zirconia
and
lithium
disilicate
should
be
avoided
in
areas
of
occlusal
contact
to
prevent
enamel
wear.
#
2014
Elsevier
Ltd.
All
rights
reserved.
§
Previously
presented
at
the
2013
IADR
meeting
in
Seattle,
WA.
*
Corresponding
author
at:
SDB
Box
49,
1720
2nd
Ave
S,
Birmingham,
AL
35294-0007,
USA.
Tel.:
+1
205
975
8302.
E-mail
address:
nlawson@uab.edu
(N.C.
Lawson).
JJOD-2362;
No.
of
Pages
6
Please
cite
this
article
in
press
as:
Lawson
NC,
et
al.
Wear
of
enamel
opposing
zirconia
and
lithium
disilicate
after
adjustment,
polishing
and
glazing.
Journal
of
Dentistry
(2014),
http://dx.doi.org/10.1016/j.jdent.2014.09.008
Available
online
at
www.sciencedirect.com
ScienceDirect
journal
homepage:
www.intl.elsevierhealth.com/journals/jden
http://dx.doi.org/10.1016/j.jdent.2014.09.008
0300-5712/#
2014
Elsevier
Ltd.
All
rights
reserved.
1.
Introduction
Advances
in
CAD/CAM
systems,
the
development
of
new
high
strength
ceramics
and
the
increasing
cost
of
noble
metals
have
all
contributed
to
the
increasing
popularity
of
all
ceramic
restorations.
From
2008
to
2014,
Glidewell
Laboratories
reported
increasing
the
percentage
of
all
ceramic
fixed
prosthesis
cases
from
23.9%
to
80.2%.
1
The
reported
incidence
of
veneer
chipping
with
bilayered
ceramic
restorations
prompted
the
emergence
of
monolithic,
complete-contour
restorations
fabricated
from
high
strength
ceramics
like
zirconia
and
lithium
disilicate.
2–4
Most
laboratory
studies
have
concluded
that
the
wear
of
enamel
opposing
zirconia
and
lithium
disilicate
is
less
than
that
of
veneering
porcelain
and
relatively
equivalent
to
enamel–
enamel
wear.
5–14
As
these
monolithic
restorations
increase
in
clinical
prevalence,
it
is
important
to
assess
their
wear
potential
in
everyday
clinical
situations,
such
as
following
occlusal
adjustment.
Several
recent
clinical
studies
have
examined
natural
enamel
wear
opposing
high
strength
ceramics.
A
study
by
Esquival-Upshaw
et
al.
concluded
that
lithium
disilicate,
either
polished
or
glazed
following
adjustment,
caused
less
wear
to
opposing
teeth
than
veneering
porcelain
after
3
years.
15
Quantitative
measurement
of
wear
in
that
study
revealed
no
difference
between
teeth
opposing
natural
teeth
or
lithium
disilicate
crowns.
16
A
2
year
study
by
Etman
et
al.,
however,
showed
less
wear
on
enamel
opposing
veneering
porcelain
(106
mm/1
yr
and
156
mm/2
yr)
than
adjusted
and
polished
lithium
disilicate
(149
mm/1
yr
and
214
mm/2
yr).
17
Stober
et
al.
measured
enamel
wear
opposing
zirconia
that
was
polished,
glazed,
adjusted
and
repolished
in
a
6
month
clinical
study.
They
found
more
wear
on
teeth
opposing
zirconia
crowns
(33
mm/6
mo)
than
teeth
opposing
natural
teeth
(10
mm/6
mo).
18
In
summary,
the
results
of
in
vivo
wear
testing
do
not
entirely
support
the
in
vitro
claims
that
zirconia
and
lithium
disilicate
produce
less
opposing
enamel
wear
than
veneering
porcelain
or
enamel–enamel
contact.
An
important
difference
between
clinical
studies
and
laboratory
studies
is
that
ceramic
crowns
are
often
adjusted
with
a
diamond
bur
and
then
re-polished
or
re-glazed
prior
to
cementation.
Several
in
vitro
studies
have
shown
that
polishing
zirconia
leads
to
less
opposing
enamel
wear
than
glazing.
5,6,8–11,13,14,19
These
results
were
confirmed
by
a
recent
systematic
review.
20
The
30–50
mm
glaze
layer
is
worn
off
by
opposing
enamel,
causing
enamel
abrasion
in
the
process.
19
A
recent
study
determined
that
polishing
lithium
disilicate
and
zirconia
following
adjustment
showed
a
trend
towards
lower
wear
on
a
steatite
antagonist
than
glazing
following
adjustment.
11
There
has
not
been
a
study
comparing
enamel
wear
against
lithium
disilicate
and
zirconia
that
has
been
adjusted
with
a
diamond
bur
and
then
polished
or
glazed.
This
study
measures
the
wear
of
enamel
against
adjusted,
adjusted
and
polished,
and
adjusted
and
glazed
zirconia
and
lithium
disilicate.
As
a
reference,
the
wear
of
enamel
opposing
polished
porcelain
and
natural
enamel
was
also
measured.
The
null
hypotheses
are
that
there
will
be
no
difference
in
the
enamel
wear
produced
by
either
type
of
ceramic
after
each
surface
treatment
and
that
there
will
be
no
difference
in
the
wear
of
enamel
opposing
either
ceramic
and
veneering
porcelain
or
natural
enamel.
2.
Materials
and
methods
2.1.
Specimen
preparation
Materials
tested
in
this
study
included
zirconia
(LAVA,
3M
ESPE),
lithium
disilicate
(IPS
e.max
Press,
Ivoclar
Vivadent),
a
veneering
porcelain
(Ceramco
3,
Caulk
Dentsply),
and
enamel.
Both
LAVA
and
e.max
specimens
were
further
divided
into
groups
of
adjusted
(A);
adjusted
and
polished
(AP);
and
adjusted
and
glazed
(AG).
Each
group
had
8
specimens
based
on
the
ability
of
previous
studies
to
statistically
discriminate
between
groups
with
an
identical
protocol.
5,6
Lithium
disilicate
specimens
were
prepared
by
pressing
IPS
e.max
Press
ingots
into
7
mm
7
mm
3
mm
0.3
mm
blocks
and
divesting
them
with
glass
beads
at
0.4
MPa
pressure.
All
specimens
were
first
roughened
with
a
fine
diamond
bur
(8879.31.014,
Brasseler
USA)
that
was
replaced
following
every
specimen.
Roughening
was
performed
with
an
electric
hand-
piece
(Ti-Max
Z95L,
NSK)
at
150,000
rpm
under
water
cooling.
No
further
treatment
was
performed
for
the
adjusted
lithium
disilicate
group.
The
adjusted
and
polished
lithium
disilicate
group
was
hand
polished
with
polishing
points
(Dialite
LD,
Brasseler
USA)
and
paste
(Zircon-Brite,
Dental
Ventures
of
America).
Specimens
were
polished
with
an
electric
handpiece
at
20,000
rpm
with
hand
pressure
and
water
cooling.
Polishing
was
performed
for
1
min
with
each
the
medium
and
fine
polishing
points.
The
adjusted
and
glazed
lithium
disilicate
group
was
covered
with
a
glaze
(e.max
Glaze
Paste,
Ivoclar
Vivadent)
and
fired
with
Ivoclar
preset
programming
(with
vacuum,
400
8C
entry
temperature,
730
8C
high
temperature
for
1
min).
The
zirconia
groups
were
prepared
by
sectioning
LAVA
blocks
into
7
mm
7
mm
3
mm
0.3
mm
specimens
with
a
diamond
cutting
wheel.
All
specimens
were
first
roughened
with
a
fine
diamond
bur
(8879.31.014)
as
described
above.
No
further
treatment
was
performed
for
the
adjusted
zirconia
group.
The
adjusted
and
polished
zirconia
group
was
hand
polished
with
polishing
points
(Dialite
ZR,
Brasseler
USA)
and
paste
(Zircon-Brite,
Dental
Ventures
of
America)
similar
to
the
method
used
for
lithium
disilicate.
The
adjusted
and
glazed
lithium
disilicate
group
was
covered
with
a
glaze
(Vita
LT
Glaze,
VITA)
and
vibrated
until
the
surface
was
uniformly
covered,
allowed
to
air
dry,
and
fired
(Without
vacuum,
960
8C
holding
temperature;
50
8C/min
temperature
increase;
closing
time
2:00
min;
500
8C
Standby
temperature;
long
term
cooling
at
0
8C).
The
veneering
porcelain
groups
were
prepared
by
building
Ceramco
3
into
7
mm
7
mm
3
mm
0.3
mm
blocks
and
firing
according
to
manufacturer’s
instruction.
The
testing
surfaces
were
wet
ground
using
400
grit
abrasive
paper
on
a
polishing
wheel
and
finished
with
a
fine
diamond
bur
(8879.31.014).
Specimens
were
then
airborne-particle
abraded
with
50
micron
alumina
at
0.21
MPa
and
ultrasonically
cleaned.
A
glaze
(Ceramco
3
Overglaze,
Caulk
Denstsply)
was
applied
to
the
specimens
and
fired
(without
vacuum,
1202
8C
low
temper-
ature,
70
8C/min
temperature
increase,
935
8C
high
temperature;
30
s
holding
time).
The
enamel
specimens
were
fabricated
from
the
flat
labial
enamel
surface
of
freshly
extracted
maxillary
central
incisors.
The
labial
surface
of
each
incisor
was
cleaned
and
polished
with
flour
of
pumice
prior
to
testing.
j
o
u
r
n
a
l
o
f
d
e
n
t
i
s
t
r
y
x
x
x
(
2
0
1
4
)
x
x
x
–
x
x
x2
JJOD-2362;
No.
of
Pages
6
Please
cite
this
article
in
press
as:
Lawson
NC,
et
al.
Wear
of
enamel
opposing
zirconia
and
lithium
disilicate
after
adjustment,
polishing
and
glazing.
Journal
of
Dentistry
(2014),
http://dx.doi.org/10.1016/j.jdent.2014.09.008
Baseline
surface
roughness
(R
a
)
of
all
the
specimens
was
determined
using
a
noncontact
light
profilometer
(Proscan
2000,
Scantron
Ltd.).
Roughness
values
were
taken
from
a
12.5
mm
length
through
the
centre
of
the
specimen
encom-
passing
the
section
of
the
specimen
in
which
the
antagonist
would
occlude.
A
2.5
mm
cutoff
length
and
a
125
surface
filter
number
were
selected
for
all
groups.
Opposing
enamel
cusps
(antagonists)
were
prepared
from
extracted
caries-free
mandibular
molars.
Their
mesiobuccal
cusps
were
standardized
to
a
cone
(diameter
=
5
mm,
height
=
2
mm)
with
a
diamond
bur
(Sintered
diamond
part
#5014006OU;
Brasseler).
The
cusp
tips
were
not
abraded
by
the
standardizing
bur
and
therefore
represent
uncut
enamel.
The
antagonist
surface
was
then
cleaned
and
polished
with
flour
of
pumice.
Initial
impressions
of
the
enamel
cusps
were
obtained
with
a
light
body
PVS
material
and
poured
in
gypsum
stone
(Silky-Rock,
Whip
Mix
Corp.)
2.2.
Wear
testing
The
mechanisms
and
testing
parameters
of
the
UAB
wear
machine
have
been
described
thoroughly
in
a
previous
publication.
21
Basically,
the
machine
operates
by
applying
a
vertical
load
from
the
antagonist
onto
the
specimen,
sliding
horizontally,
and
then
repeating
the
cycle.
The
specific
parameters
for
this
test
were
a
10
N
load,
0.4
Hz
frequency,
2
mm
sliding
distance,
33%
glycerine
lubricant,
and
400,000
testing
cycles.
Following
testing,
a
second
impression
was
taken
of
the
enamel
antagonist
and
poured
in
gypsum
stone.
4
mm
4
mm
areas
of
the
ceramic
and
enamel
specimens
and
the
antagonists
were
scanned
at
20
mm
resolution
in
a
non-contact
light
profilometer
(Proscan
5000).
The
scans
obtained
from
baseline
and
400,000
cycles
of
wear
were
superimposed
and
the
volumetric
material
loss
was
measured
with
Proform
software
(Scantron
Ltd.).
Groups
were
compared
with
a
one-way
ANOVA
(a
=
0.05).
Post
hoc
analyses
among
group
means
were
conducted
using
a
Tukey
test
(a
=
0.05).
3.
Results
Wear
of
the
ceramic
substrates
and
opposing
enamel
wear
as
well
as
the
pre-test
roughness
of
the
ceramics
are
presented
in
Table
1.
Representative
scans
of
each
ceramic
surface
are
shown
in
Fig.
1.
Normality
of
all
data
was
evaluated
with
a
Shapiro–Wilk
test
and
found
to
be
normally
distributed
(p
0.05).
3.1.
Wear
of
ceramics
The
A
and
AP
zirconia
groups
showed
no
detectable
signs
of
volumetric
loss
after
400,000
cycles.
The
veneering
porcelain
showed
the
highest
volumetric
loss
at
1.29
0.18
mm
3
.
All
other
ceramic
groups
showed
significantly
less
volumetric
loss
than
the
veneering
porcelain,
comparable
to
the
enamel–
enamel
wear.
3.2.
Wear
of
enamel
Veneering
porcelain
demonstrated
the
highest
amount
of
wear
of
opposing
enamel
(2.15
0.58
mm
3
).
The
AP
lithium
disilicate
and
zirconia
groups
showed
the
least
amount
of
enamel
wear
(0.36
0.09
mm
3
and
0.33
0.11
mm
3
respec-
tively).
For
lithium
disilicate,
the
AG
and
AP
groups
had
statistically
similar
enamel
wear,
but
only
the
AP
group
produced
less
enamel
wear
than
the
A
group.
For
zirconia,
the
AP
group
had
less
enamel
wear
than
the
A
and
AG
groups.
No
statistically
significant
difference
was
seen
between
the
enamel–enamel
group
and
any
other
group
except
the
veneering
porcelain.
3.3.
Pre-test
roughness
of
ceramics
Enamel
had
an
initial
roughness
greater
than
all
polished
or
glazed
ceramics.
The
A
zirconia
and
A
lithium
disilicate
materials
had
significantly
greater
pre-test
roughness
than
the
same
material
either
glazed
or
polished.
The
veneering
porcelain
had
a
similar
roughness
as
the
AG
lithium
disilicate
and
zirconia.
4.
Discussion
The
results
of
this
study
indicate
that
polishing
zirconia
following
adjustment
with
a
fine
diamond
bur
creates
less
opposing
enamel
wear
than
glazing
it.
Polishing
and
glazing
lithium
disilicate
following
adjustment
produced
statistically
Table
1
–
Enamel
wear,
ceramic
wear
and
roughness
of
ceramics
(mean
W
standard
deviation).
Group
Opposing
enamel
loss
(mm
3
)
Ceramic
volume
loss
(mm
3
)
Original
roughness
(mm)
A
lithium
disilicate
0.53
0.2
b,c
0.42
0.21
a
1.68
0.36
c
AP
lithium
disilicate
0.36
0.09
a
0.39
0.16
a
0.56
0.14
a
AG
lithium
disilicate
0.47
0.15
a,b,c
0.47
0.15
a
0.91
0.21
a,b
A
zirconia
0.54
0.18
b,c
Undetectable
2.73
1.49
d
AP
zirconia
0.33
0.11
a
Undetectable
1.11
0.26
a,b,c
AG
zirconia
0.68
0.20
c,d
0.57
0.13
a
0.82
0.24
a,b
Veneering
porcelain
2.15
0.58
d
1.29
0.18
b
1.57
0.15
b,c
Enamel
0.45
0.12
a,b,c
0.42
0.11
a
2.63
1.14
d
A
=
adjusted,
AP
=
adjusted
and
polished,
AG
=
adjusted
and
glazed.
Superscripts
with
similar
numbers
represent
statistically
similar
groups.
j
o
u
r
n
a
l
o
f
d
e
n
t
i
s
t
r
y
x
x
x
(
2
0
1
4
)
x
x
x
–
x
x
x
3
JJOD-2362;
No.
of
Pages
6
Please
cite
this
article
in
press
as:
Lawson
NC,
et
al.
Wear
of
enamel
opposing
zirconia
and
lithium
disilicate
after
adjustment,
polishing
and
glazing.
Journal
of
Dentistry
(2014),
http://dx.doi.org/10.1016/j.jdent.2014.09.008
similar
opposing
enamel
wear.
Covering
a
restoration
with
veneering
porcelain
significantly
increases
opposing
enamel
wear,
in
fact
it
was
the
only
substrate
which
produced
more
enamel
wear
than
enamel–enamel
contact.
Therefore,
we
reject
the
null
hypotheses.
A
previous
study
by
al-Hiyasat
et
al.
22
suggested
that
it
is
necessary
to
glaze
or
polish
porcelain
following
adjustment
to
reduce
opposing
enamel
wear.
In
their
study,
porcelain
which
was
adjusted
with
a
fine
diamond
bur
produced
more
enamel
wear
than
glazed
or
polished
specimens.
The
mechanism
of
wear
of
veneering
porcelain,
however,
is
different
than
that
of
high
strength
ceramics
like
lithium
disilicate
and
zirconia.
Veneering
porcelain
fractures
during
wear
and
creates
sharp
asperities
on
its
surface
which
abrade
opposing
enamel.
Additionally,
the
fractured
fragments
of
porcelain
may
act
as
third-body
particles,
further
potentiating
the
wear
process.
23
High
strength
ceramics,
however,
are
less
likely
to
fracture
and
therefore
maintain
a
smooth
surface
during
wear.
5,6
Therefore,
the
lower
enamel
wear
observed
against
polished
and
glazed
porcelain
in
laboratory
studies
may
reflect
a
delay
in
the
wear
of
opposing
enamel.
Once
the
smooth
surface
layer
of
glaze
or
polished
porcelain
is
roughened
and
worn
through,
the
polished
or
glazed
porcelain
will
likely
wear
at
the
same
rate
as
adjusted
porcelain.
In
summary,
previous
clinical
recommendations
for
porcelain
may
not
apply
to
high
strength
ceramics.
Other
studies
have
examined
the
wear
of
enamel
against
adjusted,
glazed
and
polished
high
strength
ceramics.
Preis
et
al.
11
compared
wear
of
a
steatite
antagonist
against
polished,
glazed
and
adjusted
lithium
disilicate
and
zirconia.
Fig.
1
–
Representative
scan
of
(top
left
to
bottom
right):
A
lithium
disilicate,
AP
lithium
disilicate,
AG
lithium
disilicate,
A
zirconia,
AP
zirconia,
AG
zirconia,
veneering
porcelain,
enamel
(note
depth
scale
ranges
from
0
to
250
mm
for
all
materials
aside
from
A
and
AP
zirconia
which
is
0–10
mm
and
veneering
porcelain
which
is
0–350
mm).
j
o
u
r
n
a
l
o
f
d
e
n
t
i
s
t
r
y
x
x
x
(
2
0
1
4
)
x
x
x
–
x
x
x4
JJOD-2362;
No.
of
Pages
6
Please
cite
this
article
in
press
as:
Lawson
NC,
et
al.
Wear
of
enamel
opposing
zirconia
and
lithium
disilicate
after
adjustment,
polishing
and
glazing.
Journal
of
Dentistry
(2014),
http://dx.doi.org/10.1016/j.jdent.2014.09.008
Although
no
statistically
significant
difference
was
noted
between
polishing,
glazing
or
adjusting
any
of
the
ceramics,
a
trend
toward
higher
steatite
wear
was
noted
for
glazing
and
adjusting.
In
their
study,
the
ceramics
were
adjusted
with
a
fine
diamond
bur
designed
for
cutting
zirconia
(BruxZir
adjustment
burs,
Axis
Dental)
that
produced
a
0.96–1.15
mm
R
a
on
zirconia
and
a
1.55
mm
R
a
on
lithium
disilicate.
A
study
by
Mitov
et
al.
8
showed
that
the
grit
of
the
diamond
bur
used
to
adjust
zirconia
affects
the
amount
of
opposing
enamel
wear.
Zirconia
adjusted
with
a
fine
30-mm
diamond
bur
produced
similar
opposing
enamel
wear
as
polished
zirconia
and
less
enamel
wear
than
zirconia
adjusted
with
a
coarse
100-mm
diamond
bur.
The
R
a
of
the
zirconia
adjusted
with
the
fine
bur
was
approximately
1.18
mm
and
the
R
a
from
the
coarse
bur
was
3.95
mm.
Amer
et
al.
compared
enamel
wear
against
lithium
disilicate
(R
a
=
1.37
rough
and
R
a
=
.25
smooth)
and
zirconia
(R
a
=
.44
rough
and
R
a
=
.12
smooth)
and
found
no
difference
between
rough
and
smooth
surfaces.
24
Ghazal
et
al.
25
showed
that
zirconia
with
a
R
a
=
.24
and
.75
produced
similar
enamel
wear,
however,
zirconia
with
R
a
=
2.75
caused
significantly
more
enamel
wear.
In
our
study,
the
R
a
of
the
adjusted
zirconia
was
2.73
mm
and
adjusted
lithium
disilicate
was
1.68
mm.
Based
on
the
results
of
these
studies,
it
appears
that
the
coarseness
of
the
bur
used
to
make
adjustments
and
a
resulting
R
a
1.5
will
significantly
increase
the
wear
of
opposing
enamel.
The
asperities
present
on
a
surface
with
R
a
1.5
may
cause
increased
abrasive
wear
to
opposing
enamel.
Other
studies
have
also
reported
that
glazed
zirconia
produces
more
opposing
enamel
wear
than
polished
zirco-
nia.
5,6,8–11,13,14,19
We
have
observed
abrasion
of
the
entire
zirconia
glaze
layer
in
previous
studies.
5,6
In
the
current
study,
we
measured
the
depth
of
the
wear
on
the
glazed
zirconia
specimens.
Assuming
no
wear
of
the
zirconia
itself,
the
glaze
layer
was
97.7
56.8
mm
thick.
As
the
glaze
is
softer
and
weaker
than
the
bulk
high
strength
ceramic,
the
glaze
layer
will
fracture
during
abrasion.
Fracture
leads
to
roughening
of
the
surface
which
abrades
opposing
enamel.
Similar
to
other
studies,
no
surface
wear
was
visible
on
polished
or
adjusted
zirconia
but
measurable
wear
occurred
on
the
surface
of
lithium
disilicate.
11,12
Lithium
disilicate
has
shown
to
produce
more
volumetric
wear
loss
than
zirconia
when
opposed
by
zirconia.
26
Some
of
these
previous
studies
showed
that
lithium
disilicate
caused
more
wear
to
opposing
enamel
than
zirconia,
7,11,12
while
another
study
found
that
lithium
disilicate
causes
less
enamel
wear
than
zirconia.
24
More
enamel
wear
opposing
lithium
disilicate
would
have
been
expected
since
this
material
experiences
more
surface
wear
and
should
have
a
resultantly
rougher
surface.
In
the
current
study,
however,
no
difference
was
seen
between
the
wear
of
enamel
opposing
lithium
disilicate
or
zirconia
for
any
surface
condition.
Smoothing
the
surface
of
a
ceramics
has
additional
utility
other
than
protecting
opposing
enamel.
Roughness
of
a
dental
restorative
material
can
contribute
to
plaque
accumulation
at
values
greater
than
0.2
mm.
27
Finishing
a
restoration
enhances
patient
comfort
as
values
around
0.5
mm
can
be
sensed
by
the
tongue.
28
Surface
roughness
of
zirconia
from
wet
adjustment
with
a
coarse
diamond
bur
(R
a
=
.51
mm
parallel
and
2.25
mm
perpendicular)
decreases
its
flexural
strength,
however,
adjustment
with
a
fine
diamond
(R
a
=
.44
mm
parallel
and
1.17
mm
perpendicular)
does
not
lower
its
flexural
strength.
29
The
limitations
of
this
study
are
that
its
results
can
only
be
applied
to
the
materials
used
in
this
study
and
the
conditions
under
which
they
were
tested.
Other
brands
of
ceramic
may
perform
differently
due
to
variation
in
grain
size,
dopant
composition,
or
phase
stability
in
zirconia
or
crystal
composition
and
proportion
in
glass
ceramics.
Additionally,
enamel
wear
would
likely
be
more
aggressive
in
patients
with
lower
salivary
output
or
higher
occlusal
forces
than
were
simulated
in
this
study.
Future
studies
should
explore
veneering
porcelain
and
ceramic
glazes
that
are
more
wear
compatible
with
opposing
enamel.
5.
Conclusion
Zirconia
is
more
wear
resistant
than
lithium
disilicate.
Polishing
zirconia
following
adjustment
causes
less
wear
of
opposing
enamel
than
glazing
it.
Glazed
and
polished
lithium
disilicate
cause
similar
enamel
wear.
The
results
of
the
study
suggest
that
it
is
preferable
to
polish
zirconia
and
lithium
disilicate
that
have
been
adjusted
with
a
fine
diamond
to
make
them
wear
compatible
with
enamel.
Acknowledgements
We
would
like
to
thank
Lance
Ramp
DMD
Ph.D.
for
his
assistance
with
the
statistical
analysis
and
the
manufacturers
for
donation
of
these
materials.
r
e
f
e
r
e
n
c
e
s
1.
Christensen
GJ.
Is
the
rush
to
all-ceramic
crowns
justified?
Journal
of
the
American
Dental
Association
2014;145:192–4.
2.
Etman
MK,
Woolford
MJ.
Three-year
clinical
evaluation
of
two
ceramic
crown
systems:
a
preliminary
study.
The
Journal
of
Prosthetic
Dentistry
2010;103:80–90.
3.
Gehrt
M,
Wolfart
S,
Rafai
N,
Reich
S,
Edelhoff
D.
Clinical
results
of
lithium-disilicate
crowns
after
up
to
9
years
of
service.
Clinical
Oral
Investigations
2013;17:275–84.
4.
Heintze
SD,
Rousson
V.
Survival
of
zirconia-
and
metal-
supported
fixed
dental
prostheses:
a
systematic
review.
The
International
Journal
of
Prosthodontics
2010;23:493–502.
5.
Burgess
JO,
Janyavula
S,
Lawson
NC,
Lucas
TJ,
Cakir
D.
Enamel
wear
opposing
polished
and
aged
zirconia.
Operative
Dentistry
2014;39:189–94.
6.
Janyavula
S,
Lawson
N,
Cakir
D,
Beck
P,
Ramp
LC,
Burgess
JO.
The
wear
of
polished
and
glazed
zirconia
against
enamel.
The
Journal
of
Prosthetic
Dentistry
2013;109:22–9.
7.
Kim
MJ,
Oh
SH,
Kim
JH,
Ju
SW,
Seo
DG,
Jun
SH,
et
al.
Wear
evaluation
of
the
human
enamel
opposing
different
Y-TZP
dental
ceramics
and
other
porcelains.
Journal
of
Dentistry
2012;40:979–88.
8.
Mitov
G,
Heintze
SD,
Walz
S,
Woll
K,
Muecklich
F,
Pospiech
P.
Wear
behavior
of
dental
Y-TZP
ceramic
against
natural
enamel
after
different
finishing
procedures.
Dental
Materials
2012;28:909–18.
9.
Park
JH,
Park
S,
Lee
K,
Yun
KD,
Lim
HP.
Antagonist
wear
of
three
CAD/CAM
anatomic
contour
zirconia
ceramics.
The
Journal
of
Prosthetic
Dentistry
2014;111:20–9.
j
o
u
r
n
a
l
o
f
d
e
n
t
i
s
t
r
y
x
x
x
(
2
0
1
4
)
x
x
x
–
x
x
x
5
JJOD-2362;
No.
of
Pages
6
Please
cite
this
article
in
press
as:
Lawson
NC,
et
al.
Wear
of
enamel
opposing
zirconia
and
lithium
disilicate
after
adjustment,
polishing
and
glazing.
Journal
of
Dentistry
(2014),
http://dx.doi.org/10.1016/j.jdent.2014.09.008
10.
Preis
V,
Behr
M,
Kolbeck
C,
Hahnel
S,
Handel
G,
Rosentritt
M.
Wear
performance
of
substructure
ceramics
and
veneering
porcelains.
Dental
Materials
2011;27:796–804.
11.
Preis
V,
Weiser
F,
Handel
G,
Rosentritt
M.
Wear
performance
of
monolithic
dental
ceramics
with
different
surface
treatments.
Quintessence
International
2013;44:393–405.
12.
Rosentritt
M,
Preis
V,
Behr
M,
Hahnel
S,
Handel
G,
Kolbeck
C.
Two-body
wear
of
dental
porcelain
and
substructure
oxide
ceramics.
Clinical
Oral
Investigations
2012;16:935–43.
13.
Stawarczyk
B,
Ozcan
M,
Schmutz
F,
Trottmann
A,
Roos
M,
Hammerle
CH.
Two-body
wear
of
monolithic,
veneered
and
glazed
zirconia
and
their
corresponding
enamel
antagonists.
Acta
Odontologica
Scandinavica
2013;71:102–12.
14.
Jung
YS,
Lee
JW,
Choi
YJ,
Ahn
JS,
Shin
SW,
Huh
JB.
A
study
on
the
in-vitro
wear
of
the
natural
tooth
structure
by
opposing
zirconia
or
dental
porcelain.
The
Journal
of
Advanced
Prosthodontics
2010;2:111–5.
15.
Esquivel-Upshaw
J,
Rose
W,
Oliveira
E,
Yang
M,
Clark
AE,
Anusavice
K.
Randomized,
controlled
clinical
trial
of
bilayer
ceramic
and
metal-ceramic
crown
performance.
Journal
of
Prosthodontics
2013;22:166–73.
16.
Silva
NR,
Thompson
VP,
Valverde
GB,
Coelho
PG,
Powers
JM,
Farah
JW,
et
al.
Comparative
reliability
analyses
of
zirconium
oxide
and
lithium
disilicate
restorations
in
vitro
and
in
vivo.
Journal
of
the
American
Dental
Association
2011;142:4s–9s.
17.
Etman
MK,
Woolford
M,
Dunne
S.
Quantitative
measurement
of
tooth
and
ceramic
wear:
in
vivo
study.
The
International
Journal
of
Prosthodontics
2008;21:245–52.
18.
Stober
T,
Bermejo
JL,
Rammelsberg
P,
Schmitter
M.
Enamel
wear
caused
by
monolithic
zirconia
crowns
after
6
months
of
clinical
use.
Journal
of
Oral
Rehabilitation
2014;41:314–22.
19.
Heintze
SD,
Cavalleri
A,
Forjanic
M,
Zellweger
G,
Rousson
V.
Wear
of
ceramic
and
antagonist
–
a
systematic
evaluation
of
influencing
factors
in
vitro.
Dental
Materials
2008;24:433–49.
20.
Passos
SP,
Torrealba
Y,
Major
P,
Linke
B,
Flores-Mir
C,
Nychka
JA.
In
vitro
wear
behavior
of
zirconia
opposing
enamel:
a
systematic
review.
Journal
of
Prosthodontics
2014.
[Epub
ahead
of
print].
21.
Lawson
N,
Janyavula
S,
Cakir
D,
Burgess
JO.
An
analysis
of
the
physiologic
parameters
of
intraoral
wear:
a
review.
Journal
of
Physics
D:
Applied
Physics
2013;46:1–7.
22.
al-Hiyasat
AS,
Saunders
WP,
Sharkey
SW,
Smith
GM,
Gilmour
WH.
The
abrasive
effect
of
glazed,
unglazed,
and
polished
porcelain
on
the
wear
of
human
enamel,
and
the
influence
of
carbonated
soft
drinks
on
the
rate
of
wear.
The
International
Journal
of
Prosthodontics
1997;10:269–82.
23.
Oh
WS,
Delong
R,
Anusavice
KJ.
Factors
affecting
enamel
and
ceramic
wear:
a
literature
review.
The
Journal
of
Prosthetic
Dentistry
2002;87:451–9.
24.
Amer
R,
Kurklu
D,
Kateeb
E,
Seghi
RR.
Three-body
wear
potential
of
dental
yttrium-stabilized
zirconia
ceramic
after
grinding,
polishing,
and
glazing
treatments.
The
Journal
of
Prosthetic
Dentistry
2014.
[Epub
ahead
of
print].
25.
Ghazal
M,
Kern
M.
The
influence
of
antagonistic
surface
roughness
on
the
wear
of
human
enamel
and
nanofilled
composite
resin
artificial
teeth.
The
Journal
of
Prosthetic
Dentistry
2009;101:342–9.
26.
Albashaireh
ZS,
Ghazal
M,
Kern
M.
Two-body
wear
of
different
ceramic
materials
opposed
to
zirconia
ceramic.
The
Journal
of
Prosthetic
Dentistry
2010;104:105–13.
27.
Teughels
W,
Van
Assche
N,
Sliepen
I,
Quirynen
M.
Effect
of
material
characteristics
and/or
surface
topography
on
biofilm
development.
Clinical
Oral
Implants
Research
2006;17:68–81.
28.
Jones
CS,
Billington
RW,
Pearson
GJ.
The
in
vivo
perception
of
roughness
of
restorations.
British
Dental
Journal
2004;196:42–5.
[discussion
31].
29.
Curtis
AR,
Wright
AJ,
Fleming
GJ.
The
influence
of
surface
modification
techniques
on
the
performance
of
a
Y-TZP
dental
ceramic.
Journal
of
Dentistry
2006;34:195–206.
j
o
u
r
n
a
l
o
f
d
e
n
t
i
s
t
r
y
x
x
x
(
2
0
1
4
)
x
x
x
–
x
x
x6
JJOD-2362;
No.
of
Pages
6
Please
cite
this
article
in
press
as:
Lawson
NC,
et
al.
Wear
of
enamel
opposing
zirconia
and
lithium
disilicate
after
adjustment,
polishing
and
glazing.
Journal
of
Dentistry
(2014),
http://dx.doi.org/10.1016/j.jdent.2014.09.008
... There was a great variation of wear-simulator properties among studies as shown in Table 2 along with other information extracted from the articles. The wear simulator types among included studies were: UAB chewing simulator, Alabama wear testing device, Custom-made chewing simulator of Zurich university, pin-on-block wear tester, chewing simulator Ghazal and Kern (2009) [18] No No Yes Yes Yes High Bai (2016) [26] Yes No No Yes Yes Low Sabrah (2012) [27] Yes No No Yes Yes Low Burgess (2014) [41] Yes [50] Yes No No Yes Yes Low Bartolo (2017) [52] No No Yes Yes Yes High Beuer (2012) [51] Yes No No Yes Yes Low Chong (2015) [48] Yes No No Yes Yes Low Hacker (1996) [53] No No Yes No No High Jung (2010) [25] Yes No No Yes Yes Low Rupwala (2017) [28] Yes No No Yes Yes Low Mundhe (2015) [39] No No Yes No Yes High Kim et al. (2012) [14] No No No Yes Yes Low Kontos (2013) [29] No No No Yes Yes Low Magne (1999) [54] No No Yes Yes Yes High Metzler (1999) [32] No No Yes Yes Yes Low Mormann (2013) [42] No [16] Yes No Yes Yes Yes Low Janyavula et al. (2013) [15] Yes No Yes Yes Yes Low Preis (2012) [55] Yes No Yes Yes Yes High Preis (2015) [56] Yes [10] Yes No Yes Yes Yes Low Stawarczyk (2013) [30] Yes No Yes Yes Yes Low Stawarczyk et al. (2016) [9] Yes No Yes Yes Yes Low Lawson (2014) [31] No No Yes Yes Yes Low Ahmadzadeh et al. (2014) [11] Yes No Yes No No High Firooz (2017) [33] No Surface treatments Bai (2016) [26] (n=110) [25] (n=60) Feldspathic dental porcelain (Vita Omega 900), cuboid zirconia crown (zirkonzahn, Prettau) ...
... Among included studies, six studies showed that zirconia groups had significantly less antagonist wear than feldspathic groups, [9,10,[14][15][16]25] and among the different surface treatments, polishing had less enamel wear than other types of surface treatment like glazing. [15,[26][27][28][29][30][31] Only one study showed that glazed zirconia can have more antagonists wear than feldspathic porcelain. [26] Monolithic zirconia had less enamel wear than conventional zirconia [9] and low-fusing feldspathic porcelain showed lower [30] antagonist wear in comparing with traditional feldspathic porcelains but there was no significant difference between the enamel wear of two low-fusing porcelains. ...
... [34] Glazed zirconia showed greater wear compared with polished zirconia, although the surface of glazed zirconia results in smooth, esthetic, and hygienic surface but the glaze layer can be easily removed during function or occlusal adjustment, and the underlying rough ceramic surface exposed and can cause aggressive damage of enamel antagonists. [15,[26][27][28][29][30][31]35] In some in vivo studies the wear behavior of glazed and polished zirconia prostheses are comparable. [36][37][38] SEM images of polished zirconia showed a surface with a more fine-grained and homogeneous texture, therefore polishing techniques decrease the surface roughness of zirconia and subsequently the wear of natural antagonists. ...
Natural teeth wear opposite to glazed and polished ceramic crowns: A systematic review
Article
It is a major concern to select a proper ceramic with acceptable strength and esthetic and minimum antagonist wear. Therefore, different ceramics were introduced to obtain these advantages with various surface treatments. The aim of this study is to evaluate and report the wear behavior of polished and glazed feldspathic and zirconia crowns in published articles up to 2020. Five electronic databases which were used in this research were MEDLINE (via PubMed), Web of Science, Cochrane Library, Embase, and Scopus from the starting date of databases to January 2020. The Keywords "zirconia," "feldspathic," "dental ceramic," "enamel," "Y-TZP," "wear," "glazed," and "polished" were used. English articles were selected in this paper. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement was used as a reporting template as much as possible. Among the initially 133 articles, 59 duplicated articles were removed, and finally, 52 articles were screened and among them, only 16 articles remained for full-text regaining. The results showed that zirconia had significantly less antagonist wear than feldspathic groups, and polishing had less enamel wear than other types of surface treatment like glazing. Only one study showed that glazed zirconia can have more antagonist wear than feldspathic porcelain. Monolithic zirconia had less enamel wear than conventional zirconia and low-fusing feldspathic porcelain showed lower antagonist wear in comparing with other types of feldspathic porcelains.
View
... 3 Clinically, grinding and polishing procedures are important steps for dental ceramic materials, especially for occlusal adjustment. 4 Appropriate polishing prevents crack propagation and subsequent biomechanical failure, reduces biofilm accumulation, 5 prevents excessive wear of opposing and adjacent teeth, 6,7 and enhances esthetics properties such as surface gloss and translucency. 8,9 Currently, a wide variety of commercial dental ceramic polishing kits are available. ...
... In contrast, zirconia requires a specific zirconia polishing kit that consists of diamond particles as the main abrasive due to their toughness, and some polishing systems also include a diamond polishing paste for the final polishing step. 6,10 To avoid having to use more than one polishing kit in the clinic, some manufacturers have introduced a multipurpose ceramic polishing kit for polishing all types of ceramic materials, such as Eve Diacera 11 and ZiLMaster. 12 Although EVE Diacera was originally developed for polishing zirconia, 13 the manufacturer subsequently claimed that it could also be used for silica-based ceramic because a high concentration of diamond fillers is incorporated. ...
... Smoothening the ceramic surface close to that of enamel decreases the enamel wear of the opposing tooth. 6 Our findings were supported by the study by Matzinger et al which found that the chairside and labside polishing had similar effectiveness in reducing surface roughness of three Table 2 Surface roughness (Ra in µm) (mean AE standard deviation) of CAD/CAM ceramic materials and after grinding and polishing and lab as-received specimens (n 10 Vichi et al reported that the surface roughness of VITA Suprinity after polishing with Suprinity polishing kits for 60 seconds was significantly lower than that of IPS e.max CAD after polishing with the Optrafine polishing kits. However, the study used specific type of polishing kit for the indicated CAD/CAM ceramic materials. ...
Surface Roughness and Hardness of CAD/CAM Ceramic Materials after Polishing with a Multipurpose Polishing Kit: An In Vitro Study
Article
Full-text available
  • Dec 2022
Objective This article evaluates the effect of multipurpose polishing kit on surface roughness and hardness of three computer-aided design/computer-aided manufacturing (CAD/CAM) ceramic materials at different polishing durations. Weight changes of the polishing bur were also determined. Material and Methods Three CAD/CAM ceramic materials were lithium disilicate glass ceramic (IPS e.max CAD), translucent zirconia (VITA YZ), and zirconia-reinforced lithium disilicate ceramic (Celtra Duo). Ceramics were ground with a diamond bur, and polished with the multipurpose polishing kit (Eve Diacera HP), which comprises coarse and fine polishing burs. Surface roughness value (Ra) was measured using a noncontact optical profilometer ( n = 10 per group) after grinding and every 15 seconds of coarse and fine polishing until 60 seconds. The complete polishing Ra was compared with the lab as-received specimens and human enamel. Surface morphology was examined using a scanning electron microscope after 60-second coarse and fine polishing and compared with the lab as-received specimens. Hardness was measured using a Vickers hardness tester on the lab as-received specimens and after the final polishing process ( n = 4 per group). Changes in surface roughness and polishing bur weight of each material were analyzed using one-way repeated-measures analysis of variance (ANOVA) and dependent t -test. One-way ANOVA was used to detect differences in surface roughness, Vickers hardness, and bur weight among materials within the same polishing duration ( α = 0.05). Results From grinding to complete polishing, the greatest Ra reduction was found in VITA YZ, followed by Celtra Duo and IPS e.max CAD. Final Ra values of all ceramics after 60-second fine polishing were not significantly different, and were similar to that of enamel and lab as-received specimens. Vickers hardness of ceramic materials did not change after grinding and polishing. Coarse polishing bur demonstrated the highest weight loss after polishing VITA YZ, followed by Celtra Duo and IPS e.max CAD. Conclusion The multipurpose polishing kit reduced surface roughness of CAD/CAM ceramic materials to the similar level of the lab as-received specimen and enamel regardless of material's hardness. The reductions of surface roughness and a coarse polishing bur weight were highest in VITA YZ, followed by Celtra Duo and IPS e.max CAD.
View
... Apesar da reconhecida excelência atribuída as cerâmicas, por sua boa biocompatibilidade, alta dureza e propriedades ópticas, estes materiais têm uma desvantagem principal: o desgaste catastrófico do dente antagonista sob certas condições. Isto o ocorre acentuadamente quando uma superfície rugosa entra em contato com o esmalte ou dentina sob altas forças oclusais 6,7 . Além disso, a lisura superficial da cerâmica contribui para diminuição do acúmulo de biofilme 8 . ...
Análise quantitativa da rugosidade superficial da cerâmica IPS E.max CAD após acabamento e polimento
Article
  • Dec 2019
Objetivo: O objetivo deste estudo foi verificar a capacidade do sistema de polimento para reduzir arugosidade superficial de cerâmicas IPS e.max após acabamento com brocas diamantadas. Métodos: Dez corpos de prova foram confeccionados a partir de blocos de cerâmica de dissilicato delítio, cristalizados e glazeados (Grupo G1) antes de serem submetidos a leitura com rugosímetro portátilem três pontos diferentes. Foi simulado ajuste oclusal com brocas diamantadas cilíndricas de granulaçãofina (Grupo G2) e feita uma nova leitura antes de realizar a sequência de polimento com o Kit EVE DiapolH8 (Grupo G3), constituído de três discos de borrachas abrasivas de granulações decrescentes. Apósanálise da rugosidade superficial do último grupo, as médias das três medições foram submetidas à análiseestatística ANOVA e ao teste Tukey com o nível de significância 5%. Resultados: A análise dos dados obtidos revelou diferença estatisticamente significativa entre os trêsgrupos, sendo que no Grupo G2 a rugosidade foi maior que no Grupo G1, que por sua vez foi maior queno Grupo G3. Conclusão: Concluiu-se que o sistema de polimento EVE Diapol H8 reduziu efetivamente a rugosidadesuperficial após acabamento com brocas diamantadas e proporcionou uma lisura superficial superioràquela dada pelo glaze. Descritores: Cerâmica. Polimento dentário. Projeto auxiliado por computador.
View
... Although the wear behavior of 3Y-TZP has been widely investigated [14][15][16][18][19][20][21][22][23][24][25][26][27], a few studies investigated the wear behavior of 5Y-TZP [23,24,[28][29][30][31]. Among these studies, some compared the wear behavior of polished 3Y, 4Y, and 5Y-TZP opposing steatite antagonists [23,24], while others investigated the wear behavior of polished 5Y-TZP opposing bovine enamel [28], human enamel [29,30], composite resin [30,31], and lithium disilicate [30,31], but the effects of staining and finishing procedures on the wear behavior of 5Y-TZP opposing dental restorative materials were not evaluated. ...
Wear Behavior of Monolithic Zirconia after Staining, Glazing, and Polishing Opposing Dental Restorative Materials: An In Vitro Study
Article
Full-text available
  • Feb 2023
The purpose of this in vitro study was to compare the effect of staining, glazing, and polishing on the wear behavior of stabilized zirconia with 5 mol% of yttrium oxide (5Y-TZP) opposing 5Y-TZP, leucite-reinforced ceramic (LC), lithium disilicate (LD), and microhybrid composite resin (MCR). Hemispheres of 5Y-TZP were divided into six groups (n = 10) according to the finishing procedure: C (control), S (staining), G (glazing), P (polishings), SG (staining plus glazing), and SP (staining plus polishing). The two-body wear test (2BW) was performed (20 N load, at 2 Hz, until 300,000 cycles). Vertical height loss of hemispheres (VHL) and wear depth of restorative materials (WD) were analyzed using a profile projector and laser confocal microscope, respectively. Data of VHL and WD were analyzed using a generalized linear model by the Wald test and t post hoc test with the Bonferroni adjustment (α = 0.05). The staining, glazing, polishing, and restorative material had a significant effect (p < 0.05) on VHL and WD. Polishing reduced VHL opposing MCR, LC, and LD. There was an increase in WD to G opposing LD and SG opposing MCR. The 5Y-TZP presented the highest wear resistance, while MCR presented the lowest. Polishing was recommended to promote staining durability and decrease wear rates opposing MCR and LD.
View
... Some studies20,[28][29][30] have examined the effect of bleaching processes on the surface properties of ceramic and LDGC materials. In the literature, surface roughness values are between 0.55 and 1.68 µm for IP[31][32][33] and 0.2 and 4.75 µm for IC.[34][35][36][37][38] In the current study, mean surface roughness values were 2.16 ± 1.15 µm for IP specimens and 2.52 ± 1.25 µm for IC specimens. ...
Effectiveness and safety of bleaching agents on lithium disilicate glass ceramics
Article
  • Dec 2022
Background. Aesthetic expectations have increased the use of aesthetic materials in dentistry. Lithium disilicates are frequently used materials for these expectations. Bleaching is another method used to provide aesthetics. Bleaching processes on restorative materials are not fully known. This study investigated the effect of at-home and in-office bleaching methods on the color change, surface roughness, and topography of lithium disilicate glass-ceramic materials produced with two different techniques and subjected to different polishing procedures. Methods. A total of 144 disc-shaped pressed and computer-aided design (CAD) lithium disilicate glass-ceramic specimens were randomly divided into four groups. Glazing and three different chair-side polishing procedures were performed. The specimens in each group were randomly divided into two groups and subjected to at-home and in-office bleaching processes (n=9). The home bleaching process was repeated with 16% carbamide peroxide agent for six hours for seven days, while the in-office bleaching process was applied with 40% hydrogen peroxide agent for two sessions of 20 minutes. After the bleaching processes, the final color and surface roughness experiments of the specimens were carried out, and the results were recorded. ANOVA and Tukey multiple comparison tests were used FOR the statistical analysis of the data (α=0.05). Results. The material*polish*bleaching, polish*bleaching, material*bleaching, and material*polishing interactions were not statistically significant regarding color and roughness changes of both specimens (P>0.05). Conclusion. Both bleaching processes can be safely applied to lithium disilicate glass-ceramic materials.
View
... 31 Moreover, similar opposing enamel wear was found for rough (R a = 0.44 μm) and smooth (R a = 0.12 μm) zirconia surfaces and for rough (R a = 1.37 μm) and smooth (R a = 0.25 μm) lithium disilicate surfaces. 48 Lawson et al 49 concluded that the wear of antagonist enamel would significantly increase only when clinical adjustments resulted in surface roughening greater than 1.5 μm. Taken together, it appears that the overall SR of indirect restorative materials remained stable after acidic challenges. ...
Effect of acidic solutions on the surface roughness and microhardness of indirect restorative materials: A systematic review and meta-analysis
Article
  • Nov 2022
PURPOSE To evaluate the effects of acidic solutions on the surface roughness (SR) and surface microhardness (SMH) of indirect restorative materials by analyzing in vivo and in vitro studies. MATERIALS AND METHODS Studies comparing the SR and SMH of indirect restorative materials after erosion were included in the meta-analysis. Meta-analyses were conducted with a random-effects model at a significance level of P < .05 using Review Manager software (Cochrane Collaboration). The literature search was conducted using Web of Science, MEDLINE (PubMed), and the Cochrane Library, with no limitations on publication year. RESULTS Of the 1,097 potentially relevant studies, 32 full-text articles were assessed for eligibility. A total of 16 articles were included in the systematic review, and 15 were included in the meta-analyses. The kappa score between the two reviewers was 0.80. The effects of erosion on ceramics, indirect composites, and hybrid ceramics were evaluated by immersion in or rinsing with acidic solutions (eg, hydrochloric acid [HCl], cola drinks, and juices). An increase in the SR (Ra values) (P < .00001; mean difference [MD] = -0.04; 95% CI = -0.06 to -0.03) and a decrease in the SMH (Vickers microhardness) (P < .00001; MD = 13.94; 95% CI = 12.33 to 15.55) were found after erosion. Subgroup analyses revealed that in vitro erosion led to significantly higher Ra values and lower VHN values than in vivo erosion; cola drinks and juices led to more surface degradation than HCl; and the SR and SMH of polymer-infiltrated ceramic network (PICN) materials remained unchanged after erosion. CONCLUSION After acidic challenges, a significantly rougher and softened surface was found for indirect restorative materials. Among all the indirect restorative materials, PICN showed the best acid resistance. Nevertheless, the changes in the SR and SMH of indirect restorative materials after erosion detected in the present study were minor and may not have any clinical significance.
View
Indirect restorative systems—A narrative review
Article
  • Jan 2023
Objective: The background and clinical understanding of the properties of currently available indirect restorative systems and fabrication methods is, along with manufacturer and evidence-based literature, an important starting point to guide the clinical selection of materials for tooth and/or implant supported reconstructions. Therefore, this review explores most indirect restorative systems available in the market, especially all-ceramic, along with aspects of manufacturing process, clinical survival rates, and esthetic outcomes. Overview: Progressive incorporation of new technologies in the dental field and advancements in materials science have enabled the development/improvement of indirect restorative systems and treatment concepts in oral rehabilitation, resulting in reliable and predictable workflows and successful esthetic and functional outcomes. Indirect restorative systems have evolved from metal ceramics and polymers to glass ceramics, polycrystalline ceramics, and resin-matrix ceramics, aiming to improve not only biological and mechanical properties, but especially the optical properties and esthetic quality of the reconstructions, in attempt to mimic natural teeth. Conclusions: Based on several clinical research, materials, and patient-related parameters, a decision tree for the selection of indirect restorative materials was suggested to guide clinicians in the rehabilitation process. Clinical significance: The pace of materials development is faster than that of clinical research aimed to support their use. Since no single material provides an ideal solution to every case, professionals must continuously seek information from well designed, long-term clinical trials in order to incorporate or not new materials and technological advancements.
View
Translucency and Wear of Pressable Lithium Disilicate and Zirconia-reinforced Lithium Silicate Glass-ceramics: An In-vitro Study
Article
  • Jan 2023
Introduction: New ceramic materials have been introduced with less research on their aesthetic outcome and durability for clinical implications. Lithium disilicate is one of the widely used materials for restoration. Recently, Zirconia-reinforced Lithium Silicate (ZLS) glass-ceramic enriched with 10% zirconia in highly dispersed glass phase of ceramic has been introduced. Aim: To investigate the translucency of pressable Lithium Disilicate (LS2) and ZLS and their effects on wear of opposing enamel. Materials and Methods: This in-vitro study was carried out at MGM Dental College and Hospital, Mumbai, Maharashtra, India, between January 2017 and January 2020. Twenty disks of 15×3 mm; 10 each of LS2 and ZLS were fabricated by hot pressing method. For translucency Commission Internationale de l’Eclairage (CIE) L*a*b values for each sample were measured against black and white background using a laboratory reflectance spectrophotometer. Translucency was calculated using Translucency Parameter (TP)= {(L*B-L*W)2+(a*B- a*W)2+(b*B-b*W)2}1/2. For wear testing same 20 disks were used as an antagonist. Enamel specimen of 20 maxillary premolar were abraded against each antagonist with two body wear testing machine in rotational motion under a constant load of 20 N at 350 rpm for 5000 cycles. The initial readings and final readings of enamel specimen in μm were measured using contact stylus profilometer. Non parametric Mann-Whitney U test was used to compare the significance of difference between two groups. Results: The TP values obtained were 23.07 and 24.04 for LS2 and ZLS, respectively (p-value=0.004). The mean wear values obtained were 0.71860 μm and 1.09500 μm for LS2 and ZLS, respectively (p-value=0.049). The difference for both the parameters was statistically significant. Conclusion: Within the limitation of this study, ZLS showed higher translucency values than LS2. Wear rate of opposing enamel was more with ZLS than LS2. Thus ZLS may provide excellent aesthetics which can be used as an option for rehabilitation in aesthetic zone.
View
Dental Materials in the Digital Age
Chapter
  • Dec 2022
Almost 50 years ago, computer‐aided design–computer‐aided manufacturing (CAD‐CAM) technologies and workflows were introduced to dentistry. The benefits of a digital workflow or CAD‐CAM processes include an increase in quality and reproducibility, efficiency, and access to newer and nearly defect‐free materials. The materials used in CAD‐CAM processes can be ceramics, polymers, or metals. If the soft milling strategy is used, manually contoured ceramic restorations are then heat‐treated to improve their mechanical and esthetic properties. Additive manufacturing of ceramic restorations is still in the nascent stage. Metal alloys that dental prostheses can be milled from include high‐noble, noble, and base metal alloys. Among the base metals, titanium alloys are most commonly used followed by cobalt–chromium alloys.
View
Effectiveness of ceramics chair-side polishing - 2D and 3D roughness evaluation
Article
  • Sep 2022
Objectives: Considering the need for intraoral polishing of zirconia restorations, this in vitro study aimed to 1) evaluate the 2D and 3D surface roughness of different types of ceramic after their finishing and polishing and 2) compare three polishing techniques using three different polishing kits. Methods: Seventy-two specimens were obtained from two types of 3Y-TZP zirconia. After sintering, a layer of a glass-based fluorapatite veneering ceramic was applied over 24 specimens of one of the zirconia ceramics. Thus, three ceramic surfaces were set: Prettau Anterior, Prettau Zirconia, and IPS e.max Ceram. The specimens were polished with a universal or specific polishing kit (n=12). After polishing, the specimens were analyzed using white-light interferometry. Kruskal-Wallis and Mann-Whitney U tests were used (α=0.05). Results: The polishing kit used did not significantly (p=0.514) affect the surface roughness of Prettau Anterior. Regarding Prettau Zirconia, the zirconia-specific polishing kit allowed a higher Sa and Ra than the universal kit (p=0.004 and p<0.001). Regarding glass-based ceramic, the specific kit led to a higher Ra (p<0.001), but no significant results were found in 3D. Conclusions: The universal polishing set showed the best results for Prettau Zirconia and glass-based ceramic, but no differences were found for Prettau Anterior.
View
An analysis of the physiologic parameters of intraoral wear: A review
Article
Full-text available
  • Sep 2013
This paper reviews the conditions of in vivo mastication and describes a novel method of measuring in vitro wear. Methods: parameters of intraoral wear are reviewed in this analysis, including chewing force, tooth sliding distance, food abrasivity, saliva lubrication, and antagonist properties. Results: clinical measurement of mastication forces indicates a range of normal forces between 20 and 140 N for a single molar. During the sliding phase of mastication, horizontal movement has been measured between 0.9 and 2.86 mm. In vivo wear occurs by three-body abrasion when food particles are interposed between teeth and by two-body abrasion after food clearance. Analysis of food particles used in wear testing reveals that food particles are softer than enamel and large enough to separate enamel and restoration surfaces and act as a solid lubricant. In two-body wear, saliva acts as a boundary lubricant with a viscosity of 3 cP. Enamel is the most relevant antagonist material for wear testing. The shape of a palatal cusp has been estimated as a 0.6 mm diameter ball and the hardest region of a tooth is its enamel surface. pH values and temperatures have been shown to range between 2–7 and 5–55 °C in intraoral fluids, respectively. These intraoral parameters have been used to modify the Alabama wear testing method.
View
The wear of polished and glazed zirconia against enamel
Article
Full-text available
  • Jan 2013
Statement of problem: The wear of tooth structure opposing anatomically contoured zirconia crowns requires further investigation. Purpose: The purpose of this in vitro study was to measure the roughness and wear of polished, glazed, and polished then reglazed zirconia against human enamel antagonists and compare the measurements to those of veneering porcelain and natural enamel. Material and methods: Zirconia specimens were divided into polished, glazed, and polished then reglazed groups (n=8). A veneering porcelain (Ceramco3) and enamel were used as controls. The surface roughness of all pretest specimens was measured. Wear testing was performed in the newly designed Alabama wear testing device. The mesiobuccal cusps of extracted molars were standardized and used as antagonists. Three-dimensional (3D) scans of the specimens and antagonists were obtained at baseline and after 200 000 and 400 000 cycles with a profilometer. The baseline scans were superimposed on the posttesting scans to determine volumetric wear. Data were analyzed with a 1-way ANOVA and Tukey Honestly Significant Difference (HSD) post hoc tests (α=.05) Results: Surface roughness ranked in order of least rough to roughest was: polished zirconia, glazed zirconia, polished then reglazed zirconia, veneering porcelain, and enamel. For ceramic, there was no measureable loss on polished zirconia, moderate loss on the surface of enamel, and significant loss on glazed and polished then reglazed zirconia. The highest ceramic wear was exhibited by the veneering ceramic. For enamel antagonists, polished zirconia caused the least wear, and enamel caused moderate wear. Glazed and polished then reglazed zirconia showed significant opposing enamel wear, and veneering porcelain demonstrated the most. Conclusions: Within the limitations of the study, polished zirconia is wear-friendly to the opposing tooth. Glazed zirconia causes more material and antagonist wear than polished zirconia. The surface roughness of the zirconia aided in predicting the wear of the opposing dentition.
View
In Vitro Wear Behavior of Zirconia Opposing Enamel: A Systematic Review
Article
  • Jun 2014
PurposeThe aim of this systematic review was to assess enamel wear on teeth opposing zirconia restorations and to evaluate factors related to the wear of natural teeth opposing zirconia restorations. Materials and Methods Five electronic databases were searched through May 2013 without limitations. The terms antagonist*, enamel, wear, and zirconi* were used. Titles and abstracts were initially screened, and those that fulfilled the inclusion criteria were selected for a full-text assessment. Studies that evaluated only the material wear were not included. ResultsThe database search strategy retrieved 142 potentially eligible studies. After the duplicate studies were removed, 62 studies were obtained. Titles and abstracts that fulfilled the inclusion criteria were selected for a full-text assessment (25). Seven laboratory studies met the inclusion criteria. In addition, reference lists from the finally selected studies were also screened. Conclusions There was a large variation in relation to wear test method quantification, applied force, lateral movement, number and frequency of cycles, number of specimens, and enamel specimen preparation. In all studies, enamel wear rates were lower against polished zirconia. Differences in the test methods did not allow for comparisons of wear rates among the studies. Clinical Significance: Polishing the surface is recommended for a full-contour zirconia restoration because polished zirconia presents favorable wear behavior opposing natural teeth.
View
Three-body wear potential of dental yttrium-stabilized zirconia ceramic after grinding, polishing, and glazing treatments
Article
Statement of problem: Zirconia complete-coverage crowns are being widely used as restorations because of their improved esthetic characteristics. Data about the enamel wear potential of this ceramic after chair side adjustments are sparse. Purpose: The purpose of this study was to investigate the 3-body wear of enamel opposing 3 types of ceramic (dense sintered yttrium-stabilized zirconia; Crystal Zirconia; DLMS) (Z), a lithium disilicate (IPS e-max CAD; Ivoclar Vivadent) (E), and a conventional low-fusing feldspathic porcelain (VitaVMK-Master; Vita Zahnfabrik) (P), treated to impart a rough, smooth, or glazed surface. Material and methods: Twenty-four specimens of each of the zirconia and the lithium disilicate ceramic were sectioned from computer-aided design and computer-aided manufacturing blocks into rectangular plates (15×12×2 mm). Twenty-four specimens of the feldspathic porcelain were formed into disks (12 mm diameter) from powders compressed in a silicone mold. All specimens (n=72) were prepared according to the manufacturers' recommendations. Specimens of each ceramic group were placed into 1 of 3 groups: group R, rough surface finish; group S, smooth surface finish; and group G, glazed surface finish. A total of 9 groups with 8 specimens each were placed in a 3-body wear simulator, with standardized enamel specimens (n=72) acting as the substrate. The wear of the enamel specimens was evaluated after 50,000 cycles. The data were analyzed with 2-way ANOVA and the Tukey HSD multiple comparison test (α=.05). Results: The data showed that the smooth zirconia group (ZS) was associated with the least amount of enamel wear (1.26 ±0.55 mm(2)). The most antagonistic enamel wear was associated with the glazed groups ZG (5.58 ±0.66 mm(2)), EG (3.29 ±1.29 mm(2)), and PG (4.2 ±1.27 mm(2)). Conclusions: The degree of enamel wear associated with monolithic zirconia was similar to conventional feldspathic porcelain. Smoothly polished ceramic surfaces resulted in less wear of antagonistic enamel than glazing.
View
Observations: Is the rush to all-ceramic crowns justified?
Article
  • Feb 2014
Summary Both PFM and ceramic restorations have significant advantages and disadvantages. As judged by the rapid acceptance of zirconia and lithium disilicate restorations, it is apparent that dental practitioners prefer the characteristics of ceramic crowns more than they like those of PFM crowns. However, PFM has decades of success, as judged by clinicalobservation and research findings, whereas the new generation of ceramic crowns has a clinical record of only a few years. There appears to be no question that the rapid decline of PFM restorations marks the beginning of the type's eventual demise. Yes, the rush to all-ceramic restorations appears to be justified, but only time will fully answer that question.
View
Enamel wear caused by monolithic zirconia crowns after 6 months of clinical use
Article
The purpose of this study was to evaluate enamel wear caused by monolithic zirconia crowns and to compare this with enamel wear caused by contralateral natural antagonists. Twenty monolithic zirconia crowns were placed in 20 patients requiring full molar crowns. For measurement of wear, impressions of both jaws were made at baseline after crown cementation and at 6-month follow-up. Mean and maximum wear of the occlusal contact areas of the crowns, of their natural antagonists and of the two contralateral natural antagonists were measured by the use of plaster replicas and 3D laser scanning methods. Wear differences were investigated by the use of two-sided paired Student's t-tests and by linear regression analysis. Mean vertical loss (maximum vertical loss in parentheses) was 10 (43) μm for the zirconia crowns, 33 (112) μm for the opposing enamel, 10 (58) μm for the contralateral teeth and 10 (46) μm for the contralateral antagonists. Both mean and maximum enamel wear were significantly different between the antagonists of the zirconia crowns and the contralateral antagonists. Gender and activity of the masseter muscle at night (bruxism) were identified as possible confounders which significantly affected wear. Under clinical conditions, monolithic zirconia crowns seem to be associated with more wear of opposed enamel than are natural teeth. With regard to wear behaviour, clinical application of monolithic zirconia crowns is justifiable because the amount of antagonistic enamel wear after 6 months is comparable with, or even lower than, that caused by other ceramic materials in previous studies.
View
Antagonist wear of three CAD/CAM anatomic contour zirconia ceramics
Article
  • Nov 2013
Little clinical information exists on the antagonist wear of anatomic contour zirconia crowns. The purpose of this in vitro study was to evaluate the 2-body wear of antagonists for 3 computer-aided design and computer-aided manufacturing (CAD/CAM) anatomic contour zirconia ceramics and veneering porcelain when opposing natural human enamel. Zirkonzahn Y-TZP (polished zirconia, zirconia with staining, zirconia with staining and glazing), Acucera Y-TZP, Wieland Y-TZP, and Noritake feldspathic ceramic were tested (6 groups). Eight disk-shaped specimens 15 mm in diameter and 5 mm thick were prepared for each group. Forty-eight specimens were fabricated for a wear test against maxillary premolars without caries or previous restorations with 240 000 masticatory cycles in a masticatory simulator. Before the experiment, the surface roughness of each ceramic was measured with a nanosurface 3-dimensional (3D) optical profiler. The surface of the specimens was observed at 50× and 1000× magnification with a field emission scanning electron microscope (FE-SEM) before and after the experiment. The data obtained were statistically analyzed by 1-way ANOVA and the Tukey test for post hoc analysis (α=.05). The SEM observations of each group revealed fine bubbles and porous surfaces in the Noritake feldspathic ceramic group, whereas the polished Zirkonzahn Y-TZP group, Acucera Y-TZP group, and Wieland Y-TZP group had smooth surfaces. The surface roughness of Zirkonzahn Y-TZP after staining and glazing was significantly greater than that of any other groups (P<.01). The tooth opposing the polished Zirkonzahn Y-TZP group demonstrated the least wear (1.11 ±0.51 mm(3)), while Zirkonzahn Y-TZP with staining and glazing produced the greatest enamel wear (3.07 ±0.98 mm(3)) among the zirconia groups. The Noritake feldspathic ceramic group showed significantly more antagonistic tooth wear than other groups (P<.05). The antagonist wear of 3 CAD/CAM anatomic contour zirconia ceramics was significantly less than the Noritake veneering ceramic because the surface character of Y-TZP is relatively uniform and homogeneous. Zirkonzahn Y-TZP with staining and glazing was significantly more abrasive than the other zirconia specimens tested. However, it was less abrasive than the Noritake veneering ceramic.
View
Enamel Wear Opposing Polished and Aged Zirconia
Article
SUMMARY Aging of dental zirconia roughens its surface through low temperature degradation. We hypothesized that age-related roughening of zirconia crowns may cause detrimental wear to enamel of an opposing tooth. To test our hypothesis, we subjected artificially aged zirconia and reference specimens to simulated mastication in a wear device and measured the wear of an opposing enamel cusp. Additionally, the roughness of the pretest surfaces was measured. The zirconia specimens, artificially aged by autoclave, showed no significant increase in roughness compared to the nonaged specimens. Furthermore, no significant difference in material or opposing enamel wear between the aged and nonaged zirconia was seen. All zirconia specimens showed less material and opposing enamel wear than the enamel to enamel control or veneering porcelain specimens. Scanning electron micrographs showed relatively smooth surfaces of aged and nonaged zirconia following wear testing. The micrographs of the veneering ceramic showed sharp fractured edges and fragments of wear debris. Zirconia may be considered a wear-friendly material for restorations opposing enamel, even after simulated aging.
View
Wear performance of monolithic dental ceramics with different surface treatments
Article
  • Feb 2013
Objective: To investigate the two-body wear performance of monolithic dental ceramics with different surface treatments. Method and materials: Standardized specimens (n = 8/ series) were fabricated from three monolithic dental ceramics (experimental translucent zirconia, experimental shaded zirconia, lithium disilicate). Four groups of each material were defined according to clinically relevant surface treatments: polished, polishedground, polished-ground-repolished, glazed. Two-body wear tests with steatite antagonists were performed in a chewing simulator. Surface roughness (R(a)) was controlled, and wear depths of specimens and antagonistic wear areas were calculated in relation to human enamel as reference. Statistical analysis of wear data was carried out using one-way ANOVA and Bonferroni multiple comparison test for post hoc analysis (α = .05). Scanning electron microscopy was applied for evaluating wear performance of ceramics and antagonists. Results: Polished, ground, and repolished zirconia showed no wear, while glaze was abraded. Irrespective of the surface treatment, wear depth of lithium disilicate was significantly (P </= .001) higher than for zirconia but only about half as high as for the enamel reference (274.14 µm). Mean relative wear areas of steatite antagonists (enamel reference: 1.25 mm2) ranged between 0.86 and 1.57 for zirconia, and between 1.79 and 2.28 for lithium disilicate, with the highest values found after grinding and glazing. Steatite surfaces were smooth when opposed to polished/ground/repolished zirconia, and ploughed when opposed to glaze and lithium disilicate. Conclusion: Translucent and shaded experimental zirconia yielded superior wear behavior and lower antagonistic wear compared to lithium disilicate. A trend to higher ceramic and antagonistic wear was shown after grinding and glazing.
View