Low energy photon irradiation by light in the far red to near infrared spectral range(630~1000nm) using low energy lasers or light emitting diode arrays has been found to modulate various biological processes in cell culture and animal models. The purpose of this study was to examine the light emitting diode irradiation effect on activity of normal human osteoblast on titanium plate in vitro by various energy density, and to observe morphologic change of NHost on titanium plate and to analysis concentration of Ca++, IP and ALP. NHost were cultured in DMEM containing 10% FBS, and observed by inverted microscope for attatchment to the surface of titanium plate. Ca++, I.P., and alkaline phosphatase( ALP) concentration in medium was calculated during 4 weeks, which was treated with Wilcoxon rank, Anova test and linear regression. Morphologic changes showed LED produced in vitro increases of cell growth of 144~256% in NHost. During a culture period, Ca++ concentration was decreased. LED treatment(>3J/cm2) stimulate calcium consumption in NHost. Statistically, a significant difference was not found between LED power density. LED treated group(>3J/cm2) had higher total inorganic phosphate concentrations than control group in NHost. Statistically, a significant difference was not found between LED power density. No significant changes were observed between ALP acitivity and LED treatment. In spite of LED power density, there were rapid growth rate of NHost and no significant of Ca++, IP and P concentration but these concentration showed predominant change than that of control.

I. 서론
 II. 연구재료 및 방법
  1. Titanium판 제작
  2. 정상인 조골세포 배양
  3. LED 조사
  4. 형광현미경 관찰
  5. Ca++, I.P(inorganic phosphate), ALP(alka-line phosphatase) 농도측정
 III. 결과
  1. 형태학적 관찰
  2. 세포외 Ca++ I.P., ALP 정량분석
 IV. 총괄 및 고찰
 V. 결론
 VI. 참고문헌

• 최민철(단국대학교 치과대학 구강생리학교실) | Choi, Min Chol
• 오충훈(단국대학교 치과대학 구강생리학교실) | Chung Hun Oh
• 천재식(단국대학교 치과대학 구강생리학교실) | Gae Sig Chun correspondence