AN EXPERIMENTAL STUDY ON THE EFFECT OF BLEACHING AGENTS

치아경조직(齒牙硬組織)에 있어 표백제(漂白劑)의 효과(效果)에 관(關)한 연구(硏究)

As widely known major cause of tooth discoloration is red blood cell in dentinal tubules after tooth trauma and extirpation. Hemoglobin in the red cells easily conbine with hydrogen sulfide and change natural tooth color into dark brown. To confirm and compare the effect of bleaching agents test material was made as fellows: No. 40 paper points were soaked in blood and put into the oven for 24 hours to dry. Dried paper points were again soaked in diluted yolk by distilled water for a minute and kept the points for a week to get fully sulfide. Hydrogen peroxide (25%), Sodium hypochlorite (2%), Sodium hyposulfate (2%), Sodium perborate and mixture of Hydrogen peroxide (25%) and Sodium perborate were employed as bleaching agents. About 0.2ml of each medicaments were put into the small test tubes and blood soaked paper points were gently placed vertically with the apex downward and kept 24 hours in the oven ($37^{\circ}C$). Every 24 hours the medicaments were renewed at 24 and 48 hours. Following are the results of the study: 1. Significant bleaching effect was found on the case of hydrogen peroxide (25%) after 24 hours. The area above 2mm from apex also fully bleached after 48 hours. 2. A mixture of hydrogen peroxide and sodium perborate treated case showed moderate effect at 24 hours and significant effect at 48 hours. High portion of the point (above 2mm) was bleached satisfactory at 72 hours. 3. The effect of sodium perborate at 48 hours showed moderate and significant at 72 hours. 4. Sodium hypochlorite and sodium hyposulfate were weak agent in bleaching. At 72 hours case revealed moderate effect and influenced on high portion of the point very weak effect.