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KMID : 0362319990240010147
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Journal of Korean Academy of Operative Dentistry
1999 Volume.24 No. 1 p.147 ~ p.155
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EFFECT OF PHOSPHORIC ACID CONCENTRATION ON THE DIFFUSION OF HEMA THROUGH DENTIN
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1윤미란/1Mi Ran Yoon
1이광원/2/3박수정/1Kwang Won Lee/23Soo Joung Park
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Abstract
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The purpose of this study was to investigate the effect of phosphoric acid
concentration on the movement of 2-hydroxyethylmethacrylate(HEMA) from bonding
resin-resin composite combination through dentin in vitro. Freshly extracted human third
molar teeth were divided into four groups each of 10 teeth. A closed chamber with 1ml
distilled water was attached to the CEJ of each tooth. An occlusal cavity of 4mm
diameter & remaining dentin thickness of 1.0-1.5mm was prepared in each tooth. Dentin
was treated with 10% phosphoric acid gel for 15 seconds. 32% phosphoric acid gel for
15 seconds, or with 35% phosphoric acid gel for 15 seconds. A control group not treated
with acid gel was also prepared. The cavities were rinsed, dried and then treated with
the HEMA-containing All-Bond 2 primer & bonding resin which was light-cured for 10
seconds. The cavities were then restored with Z100 composite resin(shade:A3.5:3M Dent.
Prod. USA) & light cured for 30 seconds.
Water samples were retrieved from the chambers over a time course (4.32, 14.4, 43.2,
144 & 432 minutes ; 1, 3 & 10 days ) and analyzed by high performance liquid
chromatography.
The results were as follows. 1. HEMA was detected in the pulp chambers of all teeth
from 4.32 minutes after resin placement The highest rate of release was in the first
sample period(0-4.32 min) & rate of release declined exponentially thereafter.
2. No significant differences were found for mean release rate for HEMA over a time
course among the four groups (p>0.05).
3. The diffusion rate was significantly (p<0.05) less for 10% phosphoric acid gel than
32% phosphoric acid gel at the second sample period(4.32-14.4 min).
4. No significant differences were found for cumulative HEMA diffusion among the four
groups at 10 days(p>0.05) and mean total(cumulative) release at 10 days for all groups
was in the 9 - 16 nmol range.
5. The cumulative release was significantly (p<0.05) less for 10% phosphoric acid gel
than 32% phophoric acid gel at the third(14.4-43.2 min) & fourth(43.2-144 min) sample
period.
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