Long-Term Antibacterial Effects and Physical - ResearchGate

16 Pages·2008·0.62 MB·English

Long-Term Antibacterial Effects and
Physical Properties of a Chlorhexidine-
Containing Glass Ionomer Cement
L. S¸EBNEM TÜRKÜN, DDS, PHD*
MURAT TÜRKÜN, DDS, PHD†
FAHINUR ERTUG˘RUL, DDS, PHD‡
MUSTAFA ATES¸, PHD§
STEFAN BRUGGER, PHD¶
ABSTRACT
Statement of the Problem: Many regions in the world do not have electricity, water, or access to
dental facilities that allows the treatment of caries with dental handpieces and rotary burs. For
restorative techniques used in these regions, an antibacterial self-adherent glass ionomer material
would contribute considerably.
Purpose: This study aimed to test if chlorhexidine diacetate (Fluka BioChemika, Buchs,
Switzerland)- or chlorhexidine digluconate (Sigma-Aldrich, Steinheim, Germany)-added ChemFil
Superior glass ionomer cement (Dentsply DeTrey, Konstanz, Germany) had any long-term
antibacterial effect against certain oral bacteria and to test the new formulation’s
physical properties.
Materials and Methods: ChemFil Superior was used as a control. Chlorhexidine diacetate (pow-
der) was added to the powder and chlorhexidine digluconate (liquid) was mixed with the powder
in order to obtain 0.5, 1.25, and 2.5% concentrations of the respective groups. Setting time,
compressive strength, and acid erosion were tested according to ISO 9917-1. Working time,
hardness, diametral tensile strength, and biaxial flexural strength were also determined. Long-
term antimicrobial activity against S. mutans, L. acidophilus, and C. albicanswere tested with
the agar diffusion method. Analysis of variance (ANOVA) was used for comparison (p <0.05).
Results: Regarding the immediate antibacterial effect for S. mutans, all the tested groups showed
inhibitions of the strain compared with the control group (p <0.05), with larger zones for the
higher concentration groups and all the diacetates. For L. acidophilus, all the groups were effec-
tive compared with the control, but the greatest antibacterial effect was observed with the 2.5%
diacetate group. The 2.5% group of chlorhexidine diacetate showed antibacterial activity up to
90 days against S. mutansand up to 60 days against L. acidophilus. The working and setting
time, acid erosion test, diametral tensile strength, and biaxial flexural strength of the tested
*Associate professor, Department of Restorative Dentistry and Endodontics, Ege University,
School of Dentistry, Izmir, Turkey
†Professor, Department of Restorative Dentistry and Endodontics, Ege University,
School of Dentistry, Izmir, Turkey
‡Associate professor, Department of Pedodontics, Ege University, School of Dentistry, Izmir, Turkey
§Associate professor, Department of Basic and Industrial Microbiology, Ege University,
Faculty of Science, Izmir, Turkey
¶Chemist, Dentsply DeTrey, Konstanz, Germany
© 2008, COPYRIGHT THE AUTHORS
JOURNAL COMPILATION © 2008, BLACKWELL PUBLISHING
DOI 10.1111/j.1708-8240.2008.00146.x VOLUME 20, NUMBER 1, 2008 29
ANTIBACTERIAL EFFECTS OF A CHLORHEXIDINE-CONTAINING GIC
groups were not different from the control ChemFil group. However, the 1.25 and 2.5% groups
of chlorhexidine diacetate had significantly lower compressive strengths than the control
group. Lower hardness values were obtained with the 0.5 and 2.5% chlorhexidine digluconate
groups in comparison with the control group.
CLINICAL SIGNIFICANCE
The results of this in vitro investigation demonstrated that chlorhexidine diacetate or digluconate
added to the ChemFil Superior glass ionomer material can exhibit long-term antibacterial
effects against S. mutansand L. acidophiluswithout compromising the physical properties
of the material.
(J Esthet Restor Dent20:29–45, 2008)
INTRODUCTION including adjacent pits and fissures, carious process, the restoration
Caries disease still remains a are restored with adhesive restora- could fail.8For that purpose, the
major public health problem tive materials.3Today, ART does improvement of filling materials to
despite the widespread use of fluo- not seem to be confined to places overcome the problems caused by
ride and the decline in caries preva- where electricity is absent. It is also incomplete removal of infected
lence observed in the majority of accepted by patients with dental dentin will be beneficial for
highly industrialized countries.1 anxiety and by children in modern increasing the success rate of
Caries epidemiology will still clinical settings, as the sound and ART further.
remain an indispensable part of pressure caused by rotary instru-
dental public health because chil- ments is omitted and local anesthe- The chemistry of the setting reac-
dren of low socioeconomic status sia is not needed.4At the beginning, tion of all versions of glass
generally have higher disease levels, conventional hand-mixed glass ionomers is essentially an acid/base
leading to an increase in caries ionomer cements (GICs) were used reaction, and the two major advan-
prevalence as well. Furthermore, with ART; later on, condensed glass tages of the material are an ion
many regions in the world do not ionomers with improved physical exchange adhesion and a continu-
have electricity, water, or access to strength were produced especially ing fluoride release. Recently, sev-
dental facilities that allows the for ART.2–4Early studies applied eral hand-mixed conventional GICs
treatment of caries with dental in the field revealed the success have been manufactured specifically
handpieces and rotary burs. For of ART.4 for the ART approach.9Reports
field treatment in these regions, a have shown that the newer, more
new technique based on manual However, dental hand instruments viscous GICs release substantially
instrumentation, atraumatic alone do not remove carious dentin less cumulative fluoride ions than
restorative treatment (ART), as effectively as rotary burs,5and less-viscous esthetic restorative
was developed.2 cariogenic bacteria can survive GICs and resin-modified GICs.10–13
incarceration under GIC restora- The effect of the lower fluoride ions
The ART is a minimal-intervention tions for up to 2 years.6,7Conse- release on the ability of the viscous
approach where demineralized quently, cavities treated by ART GICs to inhibit dental caries in
tooth tissues are removed using may have residual infected dentin, adjacent tooth tissues is not known.
hand instruments and the cavity, and if a GIC is unable to arrest the Moreover, the use of GIC as a
© 2008, COPYRIGHT THE AUTHORS
30 JOURNAL COMPILATION © 2008, BLACKWELL PUBLISHING
TÜRKÜN ET AL
restorative material for the sealing- antimicrobial effect without was mixed with 0.171g of CHX
in of caries is also questioned seriously compromising the diacetate to obtain a 0.5% formula-
because of the possible microleak- physical properties of the tion. For the 2.5% diacetate formu-
age and limitations associated with original material.15,16 lation, 29.148g of ChemFil powder
their physical properties.8 was mixed with 0.852g of CHX
Therapeutic benefit may therefore This study aimed to: (1) test if diacetate, and the half dose was
be gained by combining CHX diacetate- or CHX diglu- used in order to obtain the 1.25%
antibacterial agents with glass conate-added ChemFil Superior group. Three different GIC liquids,
ionomer materials. GIC had any long-term antibacter- containing different amounts of
ial effect, (2) test if these new for- CHX digluconate, were prepared.
Recently, researchers modified fill- mulations had similar physical The ChemFil powder was then
ing materials such as composite properties compared with the par- mixed with the undiluted CHX
resins, acrylic resins, and GICs ent material, and (3) determine the digluconate solution to obtain the
by adding chlorhexidine (CHX) optimal concentration of CHX 2.5% digluconate formulation. This
and quaternary ammonium incorporation for obtaining solution was diluted 50% with dis-
compounds.14Moreover, antiseptic antibacterial GICs for use with the tilled water to obtain the 1.25%
agents have the potential to be used ART approach. formulation. For the last group,
in combination with GICs to obtain 4.190g of CHX digluconate was
an antibacterial restorative mater- MATERIALS AND METHODS added to 95.810g of water to
ial. From the dental literature, it CHX diacetate monohydrate (Lot obtain the 0.5% CHX digluconate
appears that CHX has been incor- 37/4204/1 24999, Fluka Bio- formulation. The groups tested are
porated frequently into GIC materi- Chemika, Buchs, Switzerland), presented in Table 1.
als, and all of the studies have which is commercially available as
shown an increased antibacterial a solid substance, was added to a Agar-Diffusion Test
effect in vitro.15–17However, the conventional glass ionomer powder, The antibacterial activity was eval-
incorporation of antibacterial ChemFil Superior LY (Lot uated against S. mutansCCUG
agents in restorative materials fre- 0507001008, Dentsply DeTrey, 6519 (Culture Collection, Univer-
quently results in changes in the Konstanz, Germany) in order to sity of Göteborg, Sweden),
physical properties,14,15,18,19and it obtain three groups of 0.5, 1.25, L. acidophilusLA-CH-5DVS
is critical that the type of restora- and 2.5% concentrations (CHR.HANS, Copenhagen,
tive material show strong enough (=content) of CHX in the GIC Denmark), and C. albicansATCC
physical properties to resist occlusal formulation. The same procedure 10231 (American Type Culture
load. Therefore, antibacterial GICs was used with the CHX diglu- Collection, Rockville, MD, USA)
for use in the ART approach conate solution (Lot 084K0536, using the agar-diffusion test. These
require an optimum amount of Sigma-Aldrich, Steinheim, Ger- microorganisms were chosen
antibacterial agents, which should many), which is available as an because S. mutans is the main bac-
not jeopardize the basic properties aqueous solution. The original ratio teria responsible for caries forma-
of the parent materials.15–22It was of powder/liquid for ChemFil Supe- tion, L. acidophilus is the principle
shown that the incorporation of rior was 7.4g:1g and was used as bacteria related to caries progres-
CHX dihydrochloride and CHX a reference. For the CHX diacetate sion, and C. albicanswas recently
diacetate into GICs can increase the group, 29.829g of ChemFil powder isolated in 58 to 70% of the caries
VOLUME 20, NUMBER 1, 2008 31
ANTIBACTERIAL EFFECTS OF A CHLORHEXIDINE-CONTAINING GIC
TABLE 1. GROUPS TESTED IN THE STUDY. immediate antibacterial effect of the
Groups Materials tested groups (day 0), the plates
1 ChemFil Superior—control were incubated (Sanyo CO2incuba-
2 0.5% CHX diacetate +CF tor, MCO-17AIC, SANYO Electric
3 1.25% CHX diacetate +CF Biomedical Co., Ltd., Osaka,
4 2.5% CHX diacetate +CF Japan) at 37 ±1°C for 48 hours to
let the microorganisms grow, and
5 0.5% CHX digluconate +CF
then the diameters of the circular
6 1.25% CHX digluconate +CF
inhibition zones produced around
7 2.5% CHX digluconate +CF
the specimens (specimens +inhibi-
CF =ChemFil Superior; CHX =chlorhexidine. tion zones) were measured in mil-
limeters with a digital caliper
(Mitutoyo 0.02mm 505-646-50
in children23,24and in root carious broth culture was diluted and shockproof, Mitutoyo Corp.,
grown to a density of 107colony Tokyo, Japan) at three different
lesions in middle-aged and older
adults.25 forming units (cfu)/mL, confirmed points, and the mean was recorded
by viable cell count. as the “0”-day value. These speci-
mens were then left in the same
All procedures were carried out
Twenty-five milliliters of the respec- plates for five more days in the
under aseptic conditions in a lami-
tive culture mediums with agar incubator (total of 7 days after
nar airflow cabinet. Seventy speci-
(tryptic soy agar for S. mutans, insertion in the wells) and trans-
mens were prepared for the six
Lactobacilli MRS agar for L. ferred to freshly inoculated plates
antibacterial material-added groups
acidophilus, and Sabouraud dex- and left there for 48 hours more to
and the control (N =10) for the
trose agar for C. albicans) were obtain the inhibition zones for day
initial antibacterial effect, and 70
evenly distributed over the surface 7. The same initial procedure was
more for testing the 24-hour
of 15-cm-diameter petri dishes to a repeated, with the specimens being
antibacterial effect. For the
thickness of 5mm. For each petri left only for 24 hours in the incuba-
long-lasting procedure, only five
dish, seven standardized wells with tor to obtain day 1 values. The
specimens were used for the
a diameter of 4mm were punched specimens were then transferred to
tested groups.
into the agar with the blunt end of freshly inoculated plates and left for
a sterile Pasteur pipette. Bacterial 48 hours for the growth of the
All bacteria and yeast were culti-
inoculation was made by a bent microorganisms before the zone
vated overnight in specific culture
glass rod over the agar surfaces measurements of day 1.
mediums: tryptic soy broth for S.
with 0.5mL of the microorganism’s
mutans, Lactobacilli MRS broth for
suspension (107cfu/mL). The long-term antibacterial effect
L. acidophilus, and Sabouraud
was carried out at 7, 14, 21, 30, 40,
dextrose broth for C. albicans
The powder-liquid materials were 50, 60, 70, 80, and 90 days on only
(800.675.0908, Difco Laboratories,
mixed for 30 seconds with sterile the six tested groups because no
Detroit, MI, USA) at 37°C. The
metal spatulas to the given ratios antibacterial effect was observed in
incubation for S. mutansand L.
and inserted in the wells within the control group at day 0. After
acidophilushad a 5% CO addi-
2
1 minute with sterile dental the initial inhibition zone measure-
tion, whereas the one used for C.
instruments. For monitoring the ments (day 0 meaning immediate
albicanshad no additions. The
© 2008, COPYRIGHT THE AUTHORS
32 JOURNAL COMPILATION © 2008, BLACKWELL PUBLISHING
TÜRKÜN ET AL
effect), all the samples were an indentor (Gilmore needle) with a the GICs were packed into the split
incubated at 37 ±1°C in their initial mass of 400 ±5g, a needle having a molds and covered with the plates.
petri dishes until day 7. On that day, flat end that is plane and perpendic- One hour later, the specimens were
the respective culture mediums with ular to the long axis of the needle. ground with wet 500-grit silicon
fresh agar for the microorganisms Five specimens per group were pre- carbide paper and stored at
were placed in new petri dishes, six pared in stainless-steel blocks of 8 37 ±1°C in water for 24 hours.
standardized wells were punched mm ¥75mm ¥100mm positioned Prior to testing, the diameter of
into the agar, and new bacterial on aluminum foils and filled to a each specimen was determined
inoculation was made over the agar level surface with the mixed GICs. using a micrometer gauge, and the
surfaces with 0.5mL of the bacterial Sixty seconds after the end of mix- specimens were placed with the flat
suspension (107cfu/mL). The glass ing, the assembly, comprising mold, ends up between the plates of the
ionomer specimens were taken out foil, and cement, was placed in the universal testing machine (Zwick
of their previous petri dishes and cabinet. Ninety seconds after the machine, Z010, Zwick GmbH &
placed in the new wells. The plates end of mixing, the indentor was Co., Ulm, Germany). A compres-
were then incubated with active carefully lowered vertically onto the sive load along the long axis was
microorganisms at 37 ±1°C for 24 surface of the cement and remained applied at a crosshead speed of
hours, and the diameters of the inhi- there for 5 seconds. The process 1mm/min. The maximum force
bition zones around the specimens was repeated, starting the indenta- applied when the specimens frac-
were measured in millimeters with a tion at 30 seconds before the tured was recorded, and the com-
digital caliper the day after. This approximate setting time was pressive strength was calculated in
procedure was repeated with fresh determined, making indentations N/mm2(MPa) according to the
agar plates inoculated with fresh at 10-second intervals. The net equation CS=4F/ppd2, where Fis
microorganisms on all the setting time was recorded as the the failure load and dthe diameter
control days. time elapsed between the end of the specimen.
of mixing and the time when
For all seven groups, the setting the needle failed to make a Acid Erosion
time, compressive strength, and complete circular indentation in Five specimens per group were pre-
acid erosion were tested according the cement. pared in conditioned 5mm ¥30-
to ISO 9917-1 standards.26All mm-diameter polymethyl
specimens were mixed at a temper- Compressive Strength methacrylate (PMMA) disks with a
ature of 23 ±1°C and a relative Five specimens per group were pre- hole (5 ±0.5mm in diameter ¥2 ±
humidity of 50 ±10%. A fresh mix pared using a split stainless-steel 0.5-mm deep) in the center. The
was prepared for each specimen. mold with inner dimensions of PMMA disks were filled with the
6 ±0.1-mm height and 4 ±0.1-mm mixed cements and covered with
Net Setting Time diameter. The molds were treated separating sheets, pressed firmly
The net setting time is the period of with a 5% solution of beeswax in together, and clamped. At 180 sec-
time measured from the end of mix- volatile petroleum ether. The petro- onds after the end of mixing, the
ing until the material has set. The leum ether was given a few seconds whole assembly was transferred to
test was undertaken in a climatic to evaporate, and the residual the cabinet maintained at 37 ±1°C
cabinet capable of being maintained beeswax gave a very thin layer to and a relative humidity of 95 ±5%.
at a temperature of 37 ±1°C and a coat the surface of the mold. Within After 24 hours, the clamps and the
relative humidity of 95 ±5% using 60 seconds after the end of mixing, separating sheets were removed,
VOLUME 20, NUMBER 1, 2008 33
ANTIBACTERIAL EFFECTS OF A CHLORHEXIDINE-CONTAINING GIC
and the specimens were flattened stored at 37 ±1°C in water prior to calculated in N/mm2(MPa) accord-
wet with 1,200-grit abrasive paper. testing. After the storage time of 24
ing to the equation DTS=2F/pdt,
For each specimen, the initial depth hours and 10 days, the Vickers
where Fis the failure load, dthe
at the center of the specimen was hardness HV3 was measured by
diameter, and tthe thickness of
measured at five points using the applying a load of 29.42N on the
the specimen.
edge of the specimen holder as a samples for 30 seconds. Five
fixed reference plane. The height at indentation measurements were Biaxial Flexural Strength29
the center of the specimen was sub- carried out and averaged for
Six shell-like specimens per group
tracted from the average height of each specimen.
(20mm ¥1mm) were prepared in
the specimen holder to obtain the
Teflon molds. Within 60 seconds
Dovalue. The specimens were Diametral Tensile Strength28
after the end of mixing, the GICs
immersed horizontally into individ- Six cylindrical specimens (3mm ¥6 were packed into the ring molds
ual bottles containing 30mL of the mm) per group were prepared using
slightly in excess, covered with
eroding solution (0.1mol/L lactic split metal molds. Within 60 sec-
strips, and clamped. All the assem-
acid/sodium lactate buffer solution onds after the end of mixing, the
bly was then transferred into the
adjusted to pH 2.74 ±0.02) for 24 GICs were packed into the condi- climatic cabinet at 37 ±1°C and 95
hours at 37°C. After the immersion tioned split molds slightly in excess
±5% relative humidity. After 1
period, the specimens were and covered with strips. All the
hour, the specimens were ground
removed and rinsed with water. For assembly was then transferred into
with wet 500-grit silicon carbide
each specimen, the depth at the cen- the climatic cabinet at 37 ±1°C and paper to flatten the surfaces,
ter was measured again to obtain 95 ±5% relative humidity for removed from their molds, and
the depth of the GICs after erosion 1 hour. After that period, the speci-
stored at 37 ±1°C in water for 24
(Dt). The eroded depth, D(in mm), mens were ground with wet 500-
hours. Prior to testing, the thickness
at the center of each specimen grit silicon carbide paper to flatten
was determined for each specimen,
was calculated using the the surfaces, removed from their
which was then placed horizontally
following equation: molds, and stored at 37 ±1°C in on the universal testing machine
water for 24 hours. Prior to testing,
(Zwick machine, Z010). The speci-
D=Dt−Do the diameter and thickness of each
mens were then loaded with
specimen was determined using a
2N/min at a crosshead speed of
Hardness27 micrometer gauge. The specimens 1.5mm/min. The maximum force
A stainless-steel mold with inner were placed on the universal testing applied when the specimens frac-
dimensions of 6 ±0.1-mm height machine (Zwick machine, Z010) so tured was recorded, and the biaxial
and 3 ±0.1-mm diameter was used that the diameter of the specimen flexural strength was calculated in
for preparing the six samples per coincided with the direction of the N/mm2(MPa) according to the
group. Within 60 seconds after the compressive force. The specimens equation below:
end of mixing, the GICs were were then loaded in compression to
packed into the conditioned molds fail at a crosshead speed of 1
slightly in excess and covered with mm/min. The maximum force BiaxFS= 3F (1+n)lnds+
2pt2  dl
strips. One hour after the end of applied when the specimens frac-
d2+d2
mixing, the specimens were tured was recorded, and the (1−n) s l 
removed from their molds and diametral tensile strength was  2d2 
© 2008, COPYRIGHT THE AUTHORS
34 JOURNAL COMPILATION © 2008, BLACKWELL PUBLISHING
TÜRKÜN ET AL
where Fis the failure load, d the strains of the different groups “Day 0” results showed no antibac-
s
support ring diameter, tthe speci- were compared statistically with terial effect of the conventional
men’s thickness, d the loading ring each other. The zones were then ChemFil Superior against all the
l
diameter, dthe specimen’s diameter, checked for long-term antibacterial tested strains. For S. mutans, the
and nthe Poisson’s ratio. activity at 1, 7, 14, 21, 30, 40, difference between all the groups
50, 60, 70, 80, and 90 days and the control was significant
Working Time30
(Tables 2 and 3). (p <0.05). The greatest inhibition
The working time, which is under-
stood as the time at which it is pos-
sible to manipulate a dental material
TABLE 2. LONG-TERM INHIBITION ZONES (IN MILLIMETERS) OF THE TESTED
without an adverse effect on its GROUPS AGAINST S. MUTANS (N = 5).
Days
properties, was measured by deter-
S. mutans 0 1 7 14 21 30 40 50 60 70 80 90
mining the viscosity over the time
0.5% diacetate 23 16 14 13 13 13 12 11 10 8 0 0
using a cycloviscosimeter (Cyclo-
25 16 14 14 14 13 12 12 10 8 0 0
Viscos-E, Brabender, Duisburg, Ger- 27 17 16 16 15 15 14 12 10 9 0 0
many). The material was mixed for 24 17 16 15 15 14 13 12 10 8 0 0
30 seconds and then transferred on 26 16 15 14 14 13 12 11 10 9 0 0
the probe head, which was adjusted 1.25% diacetate 26 16 16 15 13 13 12 12 12 12 8 0
27 17 16 15 14 13 13 13 12 11 9 0
to 23°C. Exactly 60 seconds from
27 17 16 15 14 13 13 13 12 12 8 0
the beginning of mixing, the mea-
27 17 17 16 15 14 14 13 12 11 9 0
surement was started and the viscos-
26 17 16 15 15 14 13 12 12 12 9 0
ity was recorded. Five mixtures per
2.5% diacetate 28 16 16 15 14 14 14 13 12 12 11 10
group were tested.
28 17 16 15 15 14 14 14 13 13 11 9
27 17 17 16 14 14 14 14 14 12 10 9
Statistical analysis was carried out
28 18 17 16 15 15 14 13 12 12 11 9
by one-way analysis of variance 28 17 17 16 14 14 14 14 13 13 11 9
(ANOVA) and Dunnet-C test for the 0.5% digluconate 20 17 16 14 12 12 10 8 8 7 0 0
immediate inhibition zones of the 22 18 16 14 13 11 11 9 8 8 0 0
agar-diffusion test (day 0). One-way 20 17 17 15 11 11 10 10 8 0 0 0
22 18 17 15 13 11 11 9 8 0 0 0
ANOVA, Dunnet-C, and Tukey
21 17 16 14 13 13 12 11 9 7 0 0
posthoc test were carried out for all
1.25% digluconate 22 20 18 15 14 13 12 11 11 8 0 0
the physical properties except
23 22 19 16 13 13 13 12 10 8 0 0
hardness. The two-way ANOVA
22 18 18 15 13 13 12 11 11 8 0 0
with Tukey or Dunnet-C test was
23 19 19 16 13 12 11 10 9 7 0 0
used for hardness, and t-test was 22 21 18 15 14 13 12 11 10 8 0 0
used for comparing the different 2.5% digluconate 26 25 22 18 17 14 13 12 11 10 9 0
periods (p<0.05). 25 24 20 19 16 14 12 12 10 9 8 0
25 24 20 18 16 14 12 12 10 10 8 0
RESULTS 26 25 22 18 17 14 12 12 10 9 8 0
Agar-Diffusion Test 27 26 23 19 18 15 13 13 11 10 9 0
For this test, only the immediate “Day 0” means the immediate antibacterial effect, whereas “day 1” means the 24-hour effects.
inhibition zones (day 0) against the
VOLUME 20, NUMBER 1, 2008 35
ANTIBACTERIAL EFFECTS OF A CHLORHEXIDINE-CONTAINING GIC
TABLE 3. LONG-TERM INHIBITION ZONES (IN MILLIMETERS) OF THE TESTED As the control group of ChemFil
GROUPS AGAINST L. ACIDOPHILUS (N = 5). Superior had no effect on the tested
Days
microorganisms after 24 hours, it
L. acidophilus 0 1 7 14 21 30 40 50 60
was decided not to include this
0.5% diacetate 24 20 20 14 13 10 10 8 0
23 22 18 13 12 10 8 8 0 group in the long-term follow-up of
24 22 19 14 12 9 0 0 0 the antibacterial effect. Figures 2 and
23 22 19 14 12 9 8 0 0 3 show the antibacterial effects of
24 23 20 15 13 10 8 8 0
the effective groups after 1 week.
1.25% diacetate 26 24 20 16 14 10 10 8 0
26 24 22 14 13 11 10 9 8
For S. mutans, the inhibition zones’
25 23 20 14 14 12 11 8 0
diameters diminished after “day 1”
25 23 20 14 13 11 10 8 0
and stayed effective until the 70th
26 24 22 16 14 12 11 9 0
day for the 0.5% groups and the
2.5% diacetate 27 24 22 16 16 14 12 11 8
28 26 23 18 15 13 12 10 8 1.25% digluconate group. This
27 24 22 16 15 13 11 10 9 effectiveness lasted until the 80th
27 25 22 16 15 13 11 10 9 day for the 1.25% diacetate and the
28 26 23 17 16 14 12 11 8
2.5% digluconate groups, and up
0.5% digluconate 22 16 12 9 8 8 8 0 0 to the 90th day for the 2.5% diac-
20 15 13 10 9 8 8 0 0
etate groups (Table 2). For L. aci-
21 15 13 10 9 8 0 0 0
dophilus, the inhibition zones’
22 16 14 11 10 9 8 0 0
diameters were similar during the
20 15 12 9 9 8 0 0 0
first week for all the diacetate
1.25% digluconate 22 17 14 13 9 8 8 0 0
22 18 15 12 10 9 8 0 0 groups tested. The antibacterial
23 18 14 12 10 9 8 0 0 activity of the 0.5% and 1.25%
23 18 15 12 10 9 8 0 0 digluconate groups was effective
22 17 14 13 11 10 9 0 0
until the 40th day, whereas the
2.5% digluconate 26 20 16 12 11 10 9 8 0 2.5% digluconate group had some
26 22 18 14 12 10 8 8 0
inhibition effects until day 50. All
25 21 16 11 10 11 10 0 0
the samples of the 2.5% diacetate-
25 22 18 14 12 10 8 0 0
added ChemFil Superior group and
26 23 19 15 13 11 9 8 0
one of the 1.25% CHX diacetate
“Day 0”‘ means the immediate antibacterial effect, whereas “day 1” means the 24-hour effects.
showed effective antibacterial activ-
ity until the 60th day (Table 3). It
was observed that the more CHX
zones were observed in all the diac- diacetate-added ChemFil Superior concentration added to the GICs,
etate groups and the 2.5% diglu- group had the greatest inhibition the more the long-lasting antibacte-
conate-added ChemFil Superior zone against L. acidophilus, fol- rial effect against L. acidophilus.
(Figure 1A). For L. acidophilus, the lowed by the 2.5% digluconate- and
difference between the groups was 1.25% diacetate-added groups Hardness
also significant while compared with (Figure 1B). None of the tested The Vickers hardness was checked
the control (p <0.05). The 2.5% groups had an effect on C. albicans. after 24 hours and after a longer
© 2008, COPYRIGHT THE AUTHORS
36 JOURNAL COMPILATION © 2008, BLACKWELL PUBLISHING
TÜRKÜN ET AL
A Antibacterial effect of the tested groups on S.mutans (day 0) storing time (10 days) in order to
investigate if there was a leaching
2,5% digluconate 25,8 0,84 a process of the CHX, which takes
b
1,25% digluconate 22,4 0,55 place mainly at the surface of the
b
0,5% digluconate 21 1 specimens. If CHX was leached
0,45
2,5% diacetate 27,8 a out, this should have a negative
1,25% diacetate 26,6 0,55 a influence on the hardness and
0,5% diacetate 25 1,58 a, b would weaken the surface of the
ChemFil Sup 00 c specimens over time. Moreover, if a
substance is leached out of a dental
0 5 10 15 20 25 30
Mean
material (here CHX), it will always
Diameter of inhibition zone (mm)
SD
lead to the weakening of the struc-
ture, especially at the surface as
B Antibacterial effect of the tested groups on L.acidophillus (day 0)
there is a very high mobility of
b
2,5% digluconate 25,6 0,55 the substance.
c, d
1,25% digluconate 22,4 0,55
d
0,5% digluconate 21 1 The differences between the 0.5 and
0,55 a
2,5% diacetate 27,4
2.5% digluconate groups and the
1,25% diacetate 25,6 0,55 b
others were significant (p<0.05).
0,5% diacetate 23,6 0,55 c
At the 24-hour test, the 0.5 and
ChemFil Sup 00 e
2.5% digluconate-added ChemFil
0 5 10 15 20 25 30 Superior groups demonstrated sig-
Mean
Diameter of inhibition zone (mm)
SD nificantly lower hardness than the
control GIC (p<0.05). However,
Figure 1. A, Inhibition zones for S. mutans at baseline (n =10). B, Inhibition zones
at the 10-day test, all of the tested
for L. acidophilus at baseline (n =10).
groups, except the 2.5% diglu-
conate, demonstrated hardness
comparable to the original ChemFil
Superior group. While comparing
the first hardness value with that at
the 10 days, it can be seen clearly
that the hardness increased signifi-
0.5% digluconate 0.5% diacetate cantly with time for all the diglu-
conate groups except the 1.25%
1.25% digluconate 2.5% digluconate group (Figure 4). Furthermore,
because we did not see a difference
between the test groups and the
2.5% diacetate 1.25% diacetate
control in the hardness after 10
days, we could state that, if any
leaching of CHX took place on the
Figure 2. Inhibition zones observed for S. mutans after 1 week. surfaces of the CHX-added groups,
VOLUME 20, NUMBER 1, 2008 37
ANTIBACTERIAL EFFECTS OF A CHLORHEXIDINE-CONTAINING GIC
it was negligible and did not Diametral Tensile Strength original ChemFil Superior glass
influence the surface hardness of Both 2.5% diacetate- and ionomer group (Figure 7).
the specimens. digluconate-added groups tended
to have lower tensile values than Working Time
Compressive Strength the control GIC, but this difference The working time of all the CHX
In comparison with the control was not statistically different digluconate groups and the 2.5%
GIC, 1.25 and 2.5% diacetate- (Figure 6). CHX diacetate added ChemFil
added ChemFil Superior groups group was longer than the control
had significantly lower values Biaxial Flexural Strength material (p<0.05) (Figure 8).
(p<0.05), whereas the other groups All of the tested groups had biaxial
were not different (Figure 5). flexural strength comparable to the Setting Time
The setting time of all the experi-
mental GICs was not different from
0.5% digluconate the original ChemFil Superior
material (Figure 9).
Acid Erosion Test
0.5% diacetate
The conventional ChemFil Superior
1.25% diacetate
material and all the experimental
groups had the same acid erosion
value of 0.17 m.
2.5% diacetate
2.5% digluconate 1.25% digluconate
DISCUSSION
The ability of dental materials to
Figure 3. Inhibition zones observed for L. acidophilus after 1 week. inhibit recurrent caries formation is
Vickers Hardness HV3
70
63,86 63,8 62,75 63,83
60 57,23 60,43 56,2159,7 59,23 58,23 57,46
a a
a 50,46 a a a a b
es 50 a a a
u
al a 24 hours
s v 40 35,93 10 days
nes 30 b SD (24h)
d 23,55 SD (10 days)
r
Ha 20 b
10
0
ChemFil 0.5% 1.25% 2.5% 0.5% 1.25% 2.5%
Diacetate Diacetate Diacetate Digluconate Digluconate Digluconate
Materials
Figure 4. Mean and SD of the hardness of the different groups.
© 2008, COPYRIGHT THE AUTHORS
38 JOURNAL COMPILATION © 2008, BLACKWELL PUBLISHING