610 the journal of prosthetic dentistry volume 81 number 5

TOLEDANO ET AL
THE JOURNAL OF PROSTHETIC DENTISTRY
MAY 1999
611

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Teeth were prepared for microleakage evaluation by
coating the entire tooth with 1 application of nail var-
nish, except for 1 mm around the restoration margins.
These specimens were then subjected to 1000 temper-
ature cycles as suggested in a previous study.
27
Each
cycle consisted of 30 seconds at 6°C and 30 seconds at
60°C. After thermocycling, teeth were placed in a solu-
tion of 2% basic fuchsin dye (Fisher Scientific, Fair
Lawn, N.J.) for 24 hours at room temperature.
After removal of the specimens from the dye solu-
tion, the superficial dye was removed with a pumice
slurry and rubber cup. Teeth were then mounted in a
light-curing 1-component methacrylate-based resin
(Technovit 7200 VLC, Kulzer, Norderstedt, Germany)
to facilitate handling during sectioning. The resin was
cured for 24 hours (Histolux, EXAKT, Norderstedt,
Germany), then teeth were sectioned longitudinally
with a hard tissue microtome (Exakt-apparerteban,
Otto Herrman, Norderstedt, Germany) in 0.6-mm
thick sections to evaluate the dye penetration.
28
The
sections were then separated, and the cut surfaces cor-
responding to the most mesial, central (mesial and dis-
tal), and most distal portion of the tooth restoration
interface were examined at the occlusal and gingival
margins with a stereomicroscope (Olympus Co, Tokyo,
Japan) at 
×
16 magnification. Examination of the speci-
mens was undertaken at random, and the investigators
were unaware of the exact nature of the restorative
material.
Staining along the tooth restoration interface was
recorded by 2 evaluators, according to the following
criteria: 0 = no dye penetration; 1 = partial dye pene-
tration; 2 = dye penetration along the occlusal or
gingival wall, but not including the axial wall; and 3 =
dye penetration to and along the axial wall. If disagree-
ment occurred between the evaluators, a consensus was
obtained after reexamination of the specimen by both
investigators. Occlusal, gingival, and overall scores for
each group of restoration were compared with the
Kruskal-Wallis 1-way analysis of variance (ANOVA)
nonparametric statistical test to identify any statistical
significant differences between the materials, and the
Wilcoxon test was performed to compare each matched
pair of restorative materials. Significance was consid-
ered at the .05 level.
RESULTS
Microleakage scores for the occlusal, gingival, and
overall walls are presented in Table I. Kruskal-Wallis
1-way ANOVA indicated significant differences
between the restorative materials for overall, occlusal,
and gingival scores (P=.03; P=.01; P=.01, respectively).
Further matched analysis by Wilcoxon test was under-
taken to compare occlusal, gingival, and overall scores
of each material, which revealed statistically significant
differences between Fuji II LC glass ionomer cement
and Dyract resin composite, both for the occlusal
(P=.005) and gingival (P=.005) margins and also as an
overall evaluation (P=.01) (combining the occlusal and
gingival margins scores) with Fuji II LC demonstrating
the least dye penetration between these 2 products.
Vitremer glass ionomer cement revealed dye penetra-
tion scores between Fuji II LC glass ionomer cement
and Dyract resin composite, with no statistically signif-
icant differences between Vitremer glass ionomer
cement and the other 2 products.