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

Semi-quantitative analysis of early microleakage around amalgam restorations by fluorescent spectrum method: a laboratory study.

Rhodamine B, a fluorescent substance, was used as a tracer to investigate in vitro early microleakage from around amalgam restorations in machinable m...
5MB Sizes 0 Downloads 0 Views