Nd-Yag 레이저 조사가 상아질의 내산성 및 레진의 전단결합강도에 미치는 영향
THE EFFECT OF ND-YAG LASER IRRADIATION ON ACID RESISTANCE OF DENTIN AND SHEAR BOND STRENGTH OF RESIN
정동진, 손흥규,
소속 상세정보
정동진 ( ) - 연세대학교 치과대학 소아치과학교실
손흥규 ( ) - 연세대학교 치과대학 소아치과학교실
KMID : 0358919960230010206
Abstract
결론
레이저조사에 의한 상아질의 내산성변화 및 레진과의 전단결합강도를 측정하기 위하여 펄
스형 Nd-Yag 레이저를 에너지밀도 10-50J/㎠으로 조사한 후 주사전자현미 경으로 관찰하
였으며, 칼슘과 인치 용출량을 측정하여 내산성을 평가하였고 산부식군과 레이저조사군에서
레진과의 전단결합강도를 측정하여 다음과 같은 결론을 얻었다.
1. 칼슘 용출량은 대조군보다 10, 20, 30 및 40J/cm2 조사군이 적었고, 인
용출량은 대조군보다 30J/cm2 조사군이 적게 나타났다(p<0.05).
2. 레진과의 전단결합강도는 대조군보다 10J/cm2 조사군에서 약간 높게 나
타났으나 통계학적 유의차가 없었으며(p<0.05), 대조군과 10J/cm2 조사군이
20, 30, 40 및 50J/cm2 조사군보다 높게 나타났다(p<0.05).
3. 레이저 조사시 20J/cm2 조사군부터 균열이 생겼으며, 조사 에너지밀도
증가에 따라 균열의 크기가 증가하는 양상을 보였다.
4. 레진과의 전단결합강도 측정후 주사전자현미경 관찰 결과, 40J 및
50J/cm2 조사군에서는 상아질내에서 파절이 발생했다.
이상의 결과로 상아질에 Nd-Yag 레이저 조사시에는 에너지밀도를 10J/cm2
하는 것이 효과적이라고 사료된다.
#초록#
The purpose of this study was to examine the acid resistance and resin shear bond
strength of Nd-Yag laser irradiated bovine dentin. To determine the most effective
energy density of laser for improving acid resistance of bovine dentin, 120 specimen
were divided into 6 groups consisting of unlaced control group and 5 experimental
groups. The 100 specimens in the 5 experimental groups were exposed to a pulsed
Nd-Yag laser under conditions ranging from 10 to 50J/cm2 at increments
of 10J/cm2.
All of the specimens were exposed to 0.5 N HCIO4, solution containing
0.5% LaCl3 for 30 seconds for demineralization. Dissolved calcium and
phosphate concentrations in the demineralizing solution were determined by vsing an
atomic absorption spectorphotometer and the UV spectrophotometer.
To determine the resin shear bond strength of a pulsed Nd-Yag irradiated bovine
dentin, the 60 specimens were divided into 6 groups. The Control group was etched
with 10% phosphoric acid for 15 seconds and rinsed thoroughly, mixture of primers A &
B was applied 5 times on the dentin surface, and adhesive bonding resin was applied
and light cured for 20 seconds, and composite cyliders were bonded to the dentin
surface. For 5 experimental groups, after the laser irradiation, other procedures were
same as control group except being not etched. All samples were measured for the
shear bond strength by using 0.2 mm crosshead speed. SEM observations were made to
examine the change of dentin surface after laser irradiation and to examine the fractured
interface after the shear bond test.
The results were as follows :
1. Th concentration of calcium dissolved from laser irradiated dentin at the energy
densities of 10, 20, 30, and 40J/cm2 were significantly lesser than that of
untreated control group(p<0.05).
2. The shear bond strength of 10J/cm2 group was higher than that of
the control group even though it was statistically insignificant(p>0.05).
The shear bond strength of the control and 10J/cm2 groups were
significantly higher than those of 20, 30, 40, and 50J/cm2 groups(p<0.05).
3. Laser irradiation of the dentin resulted in crack formation at above
20J/cm2 of energy density and cracks were wider and deeper according to
the increase of energy density as the energy density increases.
4. Following the shear bond strength test, bond failures occurred beneath the dentin
surface in the 40 and 50J/cm2 groups.
It could be concluded that it is most effective to use 10J/cm2 of energy
density during while irradiating the dentin using an Nd-Yag laser.
키워드
Laser; Dentin; Shear bond strength; Acid resistance; SEM;
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