DentalMaterialsJournal 11(1): 45-58, 1992
45
Semi-Quantitative Analysis of Early Microleakage Restorations by Fluorescent Spectrum Method: A Laboratory Study
around Amalgam
Jee Youn KIM, Yoshifumi TAKAHASHI, Masashi KITO, Yoshiya MORIMOTOand Jiro HASEGAWA Department of DentalMaterialScience,Schoolof Dentistry, Aichi-Gakuin University, 1-100Kusumoto-Cho, Chikusa-Ku, Nagoya464,Japan Receivedon May24,1991. Acceptedon April4, 1992.
Rhodamine from
around
B, a fluorescent amalgam
substance,
restorations
was used
in machinable
as a tracer
to investigate
mica glass-ceramic
after
in vitro early thermal
stress.
amalgam, i.e., low-copper spherical, low-copper lathe-cut, high-copper admixture, high-copper high-copper spherical, were examined in the present study. The results indicated that early from
alloys
of lathe-cut
particles
was lower
and high-copper
amalgam
restorations.
particles
to exhibit
the lowest
tended
Key words:
Amalgam,
Microleakage,
than that
from alloys
A high-copper early
amalgam
of spherical with
a mixture
particles
microleakage Five types
of
lathe-cut, and microleakage
in both low-copper
of lathe-cut
and spherical
microleakage.
Rhodamine
B
INTRODUCTION Dental amalgams
are widely used in the restoration
of decayed
teeth because
of their
easy manipulation and of their passable mechanical properties. However, the difference in coefficient of thermal expansion, the lack of chemical bonding, and the shrinkage during setting produce gaps between the cavity walls and the amalgam restoration. The subsequent penetration of fluids, debris, and microorganisms around the margins of the restoration may cause hypersensitivity and secondary caries. Therefore, various test methods have been designed to study marginal leakage around amalgam restorations. Christen et al.1) used fluorescent dye penetration method in their tests, because fluorescent dye materials successfully penetrate flaws or crevices in test objects. Fluorescent dyes are useful as tracers, both topically and systemically, since they are detectable in extremely dilute concentrations. In another recent study, Leinfelder et al.2) proposed the use of calcium hydroxide as an agent for monitoring microleakage and demonstrated that it can be used to detect microleakage in vivo. Isenberg et al.3) applied this method in vivo and reported a major difference from previous studies in that the detecting agent leaks from within to the outer environment. These studies gave rise to a new laboratory method for the testing of microleakage in amalgam restorations. The purpose of the present investigation is to describe a new in vitro method for measuring microleakage around amalgam restorations and report the results of its use in experiments
on low-copper
and high-copper
amalgam
alloys under thermal
cycle conditions.
46
J.Y. KIM, Y. TAKAHASHI,
M. KITO, Y. MORIMOTO
MATERIALS
AND
and J. HASEGAWA
METHODS
Materials Human
teeth
are
experiment
described
experiment,
however,
base
infiltrated
the
examined
of the
human First,
on
120•Ž.
of
Moreover,
Taira
have
preliminary
was
cutting
breakdown.
alloys
were
used
alloys
were
selected
particles
human
with
in
(spherical,
this
Cylindrical
cavities,
thickness
plates 0.25mm) These
only
were
test
to
reports,
and
this
property can
we
decided Three
2 lists
their
the
chemical
a potential in
machinable
used
for
were
amalgam
alloys
composition,
Finally,
glass-ceramic,
mica
also
from
without
teeth.
From
these
glass-ceramic
high-copper
used
but
range
easily
mica
six
A porosities
et al.4).
cut
typodont
and
for
expansion
the
Xu
it was
machinable
low-copper
no
thermal
by
the
measure therefore
microanalyzer@.
of
be
cavity
1.
within
of
the
the
replacement
There
that
of
to
Table
X-ray 1.
reported
use
in
We
as
found
to
preliminary
placed
shown
coefficient
teeth
and
sort
the
it difficult
10.4•~10-6/•Ž
human
the
restoration.
an
its was
material
study.
Table for
lathe-cut of
material
present
study.
not
of the
this
made
Photo
measured
that
the
using in
in
was
the
is
shown
obtained
of
that
in the
we
to
respect
and
teeth
Preparation
glass-ceramic
similar
material
material is
value
This and
for used
which
glass-ceramic*
this
Secondly,
property
experiments of
of
material were
paper
tooth
this
surface
average
demonstrated
instead
dried.
material.
value
of
cut
best teeth
tubules.
the mica
surface
this
The
the
et al.5)
cut of
the
filter
dentinal
between
a machinable
the
the
This
examined
gap
be human
the
composition
image
a dilatometer@@.
20 to we
of
within
through
the
to When
B
cavity in
observed
surface
report.
chemical
electron
the
using
The
we
secondary
pulp fluid
properties
teeth.
considered
this
rhodamine
the
exchange
generally in
amalgam
in
this
study.
for
the
shape
These of
their
admixed).
specimen 4.5mm
wide
measuring were
Table
3mm
deep
were
prepared
10mm•~10mm•~5mm.
immersed
placed
and
at
the
1
in
a
base
of
Chemical mica
1%
Filter
aqueous each
solution
cavity
composition glass-ceramic,
manufacturer
* MACOR , Ishihara Chem. Ltd., Tokyo, Japan ** Toyo Roshi Co . Ltd., Tokyo, Japan *** Wako Pure Chem . Ind. Ltd., Osaka Japan @JCMA-733, Jeol Co. Ltd., Tokyo, Japan @@ TMA -8140 , Rigaku Co. Ltd., Tokyo, Japan
(wt%)
before
of as
a
papers** of it
rhodamine was
machinable
specified
in
by
the
filled
machinable
mica
(diameter B*** with
4mm, and amalgam.
then
MICROLEAKAGE
Photo
1
Photomicrograph machinable
Table
#
2
Materials
Hi -Atomic
used
OF AMALGAM
mica
of
cut
surface
47
of
glass-ceramic.
in this study
M , GC Corporation., Tokyo, Japan Non Zinc Luna Alloy , GC Corporation., Tokyo, Japan ### Dong Myung , Dong Myung Dental Material Industrial Co., Kyung-KiDo, Korea #### Dispersalloy , Johnson & Johnson Dental Products Company, East Windsor, NJ, USA ##### Lumi Alloy , GC Corporation., Tokyo, Japan ###### Hi -Veraloy , Hankuk Engelhard Corp., Kyung-KiDo, Korea ####### Spherical -D , Shofu Dental Mfg. Co., Kyoto, Japan ######## Tytin , The S S White Company, South St., Holmdel, NJ, USA ######### Sybraloy , Kerr Manufacturing Company, Roumulus, MI, USA ##
48
J.Y. KIM, Y.TAKAHASHI,M.KITO,Y.MORIMOTOand J. HASEGAWA Table
Amalgam gam
3
Methods
pastes
were
specimens 2mm)
with
based
on
method
was at
the
removed 37•Ž
test
In
to
phous
cycling cycling
have
tures
of the
varied 4 and
We
necessary heating
of
temperature to
on
through to
increase
method.
immersion 60•Ž.
in Between
Each a
water
The
$
amount wave
of of
the
marginal not
The
24
hours
immersed
in
were
test
from
15
2500.
tube
consisted by
three
stored
be
of
at
to
ten
for
least
of
incubator
at
in
minutes,
the
current
However,
using
repetitions immersion
we
minutes an
three a
to
tempera-
three
60•Ž
was
restora-
two
60•Ž.
is
amor-
amalgams.
used to
used
4 and of
solution
an
to
to
minutes in
have seconds
interval
the
amalgam
a few
wall of
study
of
investigators
of
cavity
present
surface
from
conditions
an
and consisting
from
water
is
indirect minutes bath
at
with
an
37•Ž.
B
an
measured
using
a spectrofluorophotometer@@@
emission
wave
length
HIMIX VS-II , GC Corporation., Tokyo, Japan Van-Mix II-M , L.D. Caulk Company, Milford, DE, USA CAPMASTER , S.S. White Company, Philadelphia, PA, USA @@@ RF-540, Shimazu Co. Ltd., Kyoto, Japan
$$ $$$
was paste
for
were
the
the
temperatures that
thus
of
vary
the
the
Since on
ranges
using
followed
B was 525nm,
incubator
debris,
microleakage
majority
deciding
of
tubes
seal7).
used
employed
cycling
rhodamine
condenser
amalgam
restoration
This
performed
of
times
cyclings
4•Ž,
test
Amal-
pressure
specimens
the
process,
evaluation
temperature
at
hand
excess in an
the
a
3).
condensation
stored
between
experimentation
thermal
of
in
daily
rhodamine
length
the
the
studies
bath
cycling,
Measurement
excitation
the
space
study8-21).
preliminary
then
(Table
using
the
condensation,
this,
polishing
immersion
three
After were
was
cycles
these
settling
the
improve
to
The
cavities of
Following
the
for
study
60•Ž.
instructions
water.
polishing
or
referred
discovered
to
cylindrical
al.6)
100%.
from
conditions
from
58
number
experiment,
supposed
the
samples
restorations, debris
manufactures'
et
The of
the
Measurement
Lussi
distilled
microleakage,
Thermal
tions
of
with
Thermal
3.5kg.
by
humidity
is
pure
into to
blade.
5ml
filled
materials,
determine
and
a razor
amalgam
be
1.5
described
a relative
common
known
of
in this study
to
condensed
force
containing
used
according
then
a
using
with
tubes
mixed
were
(diam.
and equipment
of
575nm
and
a
spectrum
band
MICROLEAKAGE
OF AMALGAM
49
width of 5nm. As a control, samples of the machinable mica glass-ceramic and set amalgams alone were subjected to the same thermal cycling process as the test specimens to determine whether either contained other fluorescent material. No other spectrum in this region was detected. Measurement of rhodamine B was performed after one, three, five, seven, and ten days of the immersion period. Five samples of each alloy were tested. Averages and standard deviations were calculated. Observation of interface between restoration and cavity walls We observed the interface between the amalgam fillings and cavity walls in the machinable mica glass-ceramic by scanning electron microscopy to examine the relationship between the concentration of released rhodamine B and the size of the gap. The specimens which were employed to measure the concentration of rhodamine B were fixed to the machinable mica glass-ceramic with a small amount of adhesive and then sectioned longitudinally. The specimens were ground on 600 and 1000 grid silicon carbide papers under cold water. After polishing, the specimens were washed with distilled water in an ultrasonic cleaning machine for five minutes.
RESULTS The cumulative amounts of rhodamine B found dissolved in the distilled water from the immersion of various amalgams subjected to thermal stress are shown in Figs. 1 to 3. The results for low-copper amalgams are presented in Fig. 1. HAM showed marked microleakage on the first day, which levelled off thereafter. Although the microleakage from DM was smaller, this alloy showed a similar pattern to NAM. On the other hand, while microleakage
Fig. 1
from
Cumulative
LUNA
rhodamine
from low-copper thermal cycling Figures
was slight on the first day, but increased
show averages
deviations.
B dissolution
amalgams immersion
after test . and standard
Fig. 2
at a steady
pace
Cumulative rhodamine B dissolution from high-copper (admixed type) amalgams immersion
after test.
ages and standard
thermal Figures
cycling show aver-
deviations.
50
J.Y. KIM,Y.TAKAHASHI,M. KITO,Y.MORIMOTO and J. HASEGAWA
thereafter. The results for admixed high-copper amalgams are presented in Fig. 2. LUMI showed a pattern of microleakage similar to that of HAM, although the amount was smaller. On the other hand, DIS showed a small amount of microleakage in a pattern similar to that of LUNA. The microleakage from this amalgam after 10 days was the smallest of all the amalgam alloys used in this experiment. The results for single-composition high-copper
amalgams
are presented
in Fig. 3. TY
and SP-D showed almost the same pattern, and the amount of microleakage from these amalgams on the first day was marked. SY showed a pattern similar to those of TY and SP -D , but with a smaller amount. Although the microleakage from HV was slight on the first day, it increased after three days and leveled off thereafter. In Fig. 4, the total amount of microleakage from each amalgam after immersion in distilled water for ten days has been arranged according to copper content and particle shape. Table 4 shows a comparison of the total amount of microleakage from each amalgam alloy using the two-tailed t-test. Of the low-copper amalgams, HAM, which is composed of spherical particles, showed a greater microleakage than did alloys of lathe-cut particles (LUNA and DM); a highly significant difference was observed between HAM and both LUNA and DM (p