Influence Of The Concentration Of Hydrogen Peroxide And Titanium Dioxide And Different Anti-sensitive Agents And Light Source On The Tooth Bleaching Effect

BackgroundBleaching methods to whiten teeth without reducing the surface have been studied, and new bleaching agents have been developed. Bleaching methods to improve the color of teeth without reducing the surface are selected based on the cause of the pigmentation and the amount of discoloration. Although slight exogenous pigmentation due to food and drink can be removed by mechanical cleaning of the tooth surface, office and home bleaching methods are selected in cases of slight tetracycline tooth staining, discoloration due to aging, and exogenous pigmentation that cannot be improved by mechanical tooth surface cleaning.We evalvated increases in the concentration of hydrogen per oxide and a titanium dioxide catalyst influenced the efficacy of the TION in Office bleaching system(TION, GC,). Bovine teeth were immersed for7days in a pigmentation liquid produced by boiling black tea, to discolor the specimens. Before bleaching treatment, the discolored specimens was measured using a colorimeter. Bleaching treatment was then done using the TION in office system. The color was measured again after the bleaching,and for three more times. Thereafter, then every7days for three more times, in addition,the bleaching agent of the TION gel was mixed with an equal volume of35%hydrogen peroxide, and bleaching was performed in the same way as for the controls (H2O2-added group). Using an experimentally produced reactor in which the volume of the titanium dioxide V-CAT contained in the reactor was doubled, bleaching was performed using the mixed gel of TION in the same way as for the controls (TiO2-added group). Measurements were converted to CIE L*a*b*, using color analysis software, and ΔE*ab, which represents color differences before and after bleaching.The4color differences before and after each bleaching treatment, and color changes between the first measurement before bleaching and fourth measurement after bleaching were calculated. Measurements were tested using one-way layout analysis of variance and Tukey’s test (p<0.01). Changes in the color difference value AE*ab before and after treatment were significantly greater after the first treatment under each condition. Although changes in the value were less than6.0after the second, third, and fourth treatments in the controls, changes in the value were greater than6.0up to the second treatment in the H2O2-and TiO2-added groups.ObjectivesTitanium dioxide has been used as a photocatalyst for bleaching. Nonami discovered that a mixture of titanium dioxide and a low concentration of hydrogen peroxide is effective for tooth bleaching, and reported that bleaching of the enamel surface is possible. It has been revealed that these titanium dioxide-containing bleaching agents can have a marked bleaching effect equivalent to that of conventional bleaching agents whose main component is a high concentration of hydrogen peroxide, The effect of titanium dioxide is the result of its,even when there is a low concentration of hydrogen peroxide.Office bleaching products with a reduced concentration of hydrogen peroxide using titanium dioxide as a catalyst are now commercially available3,4). Generally, titanium dioxide photocatalysts strongly react with ultraviolet rays which are harmful to humans, but have essentially no reaction with visible light. However, a visible light activative type of photocatalyst (V-CAT), which is in TiON in Office system, reacts adequately not only with ultraviolet, but also with visible light, and can be used for whitening with a dental irradiation apparatus for bleaching. We evaluated now increases in the hydrogen per oxide and titanium dioxide catalyst in TiON, which contains the titanium dioxide V-CAT, influenced bleaching of the teeth. The probability of the occurrence of dentin hypersensitivity after bleaching and bleaching of, with mild allergic conditions have reached55%and75%, the existence of enamel enamel leaves and tiny chap is associated with the phenomenon of closely related, for pulp tooth bleaching, in recent years, concentration of titanium dioxide as catalyst to reduce hydrogen peroxide, products thereby inhibiting the irritation to pulp are emerging in the market. On the other hand, when fluoride aluminosilicate glass ion using nanoparticles have an effect on the hydroxyapatite was nanoseal in the manufacturer’s instructions under coating its effect on the bleaching effect was the review.Materials and methodsPart1 We were studied bleaching using a discolored bovine tooth model. All experiments were performed in accordance with the Guidelines for Animal Experiments of Osaka Dental University (apporoval number:13-03021).part21.Frozen bovine teeth were defrosted, and after removing the roots and dental pulp, the inside of the dental pulp cavity was treated using5%hypochlorous acid solution for1minute. After washing with water and drying, the teeth were treated with37%phosphate gel (K-echant, Kuraray Noritake Dental, Tokyo, Japan) for1minute, washed with water, and dried. The teeth were then immersed for7days in a pigmentation liquid produced by boiling black tea, to produce the discolored specimens.2. Before bleaching treatment, the color of the center of the coronal area of the discolored specimens was measured using a colorimeter (ShadeEye, Shofu,Kyoto, Japan). Thereafter, bleaching treatment was performed using TiON, according to the manufacturer instructions. After applying the TiON reactor and drying, the mixed gel from syringes A and B was applied, and the teeth irradiated using an LED apparatus for bleaching (Cosomo Blue, GC,Tokyo, Japan) for10minutes. This was done three times.3. in the same area, followed by measurement of the color (first measurement after bleaching treatment). Color measurement was performed three times per specimen, and the mean was set as the measurement value. Thereafter, the specimens were preserved in saline solution, and bleaching treatment was performed every7days for a total of four times, followed by measurement of the color each time. These four measurements represent the control group.4. Inaddition, bleaching was performed in the same way as for the controls using a bleaching agent in which the mixed gel of TiON was mixed with the same volume of35%hydrogen peroxide,(H2O2-added group).5. An experimentally produced reactor was made in which the volume of the titanium dioxide V-CAT contained in the reactor was doubled, The reactor was applied and the teeth were dried, and bleaching treatment was performed using the mixed gel of TiON in the same way as for the controls (TiO2-added group). Bleaching treatment was performed four times as in the controls.part3Measurements were converted to CIE L*a*b*, using color analysis software (Sai-check ver.4.0, Konica Minolta.), and L*a*b*was calculated. The reference value before treatment was set as L*0,a*0,b*0, the value after the first second,third and forth treatments were set as L*l,a*1,b*1, L*2,a*2,b*2, L*3,a*3,b*3, and L*4,a*4,b*4respectively. Furthermore, ΔE*ab, which represents the color differences before and after bleaching, was calculated using the equation ΔE*ab=[(AL*)2+(Δa*)2+(Δb*)2]1/2.The color change between the first measurement before treatment and fourth measurement after treatment were calculated to judge the effect of bleaching.Results1、Figures1-5show the results of L*a*b*obtained from the experiments. L*markedly increased after the first bleaching under each condition in comparison with before treatment, and gradually increased after the second, third, and fourth bleachings.2、The value a*markedly decreased after the first bleaching in comparison with before treatment, but showed no changes after the second, third, or fourth bleachings. The value b*gradually decreased under each condition.3、Compared with before treatment, color difference value ΔE*ab after treatment was significantly greater after the first treatment under each condition. Although changes in the value were less than6.0after the second, third, and fourth treatments in the control group, changes in the value were greater than6.0until the second treatment in the H2O2-and TiO2-added groups.4、The change in the color difference ΔE*ab between the first measurement before treatment and the fourth measurement after treatment was42.8in the H2O2-added group, showing the greatest value while that in the control group was36.6, and that in the TiO2-added group was35.3. No significant differences were noted among the different conditions.ConclusionsAlthough the experimental results showed no significant differences, increases in the concentration of hydrogen peroxide raised the color difference value△E. However, bleaching using a high concentration of hydrogen peroxide should be avoided, because it may penetrate soft tissue on contact, and frequently causes hypersensitivity. Furthermore, although we doubled the content of titanium oxide contained in the reactor, no significant differences in the color difference value ΔE were confirmed, in comparison with the control. We think that this was because, even though the amount of the catalyst was increased, the bleaching effect was not affected when the amount of activated hydrogen peroxide remained the same. However, because the standard deviation of the color difference value AE markedly decreased, in comparison with other conditions, it was thought that increasing the catalyst was effective in stabilizing the bleaching effects. Furthermore, although the irradiation time was set at10minutes as in the control in this study, because it is possible to decrease the irradiation time when the amount of photocatalyst is increased, we would like to evaluate this in the future.Regarding color differences, Ruyter reported that marked color changes are clinically noted when ΔE*ab is greater than3.3. Toukou classified the value of ΔE*ab into6grades and evaluated the results of bleaching.They found that resulted when the value was6.0-12.0, marked differences were noted when the value is3.0-6.0, extreme differences are present.When this evaluation was applied to the present results, both the H2O2-and TiO2-added groups showed changes greater than6.0up to the second treatment, which corresponds to the range of3.0-6.0. Therefore, effects producing marked differences were achieved. Our experimental results verified that the bleaching effects of TiON can usually be obtained with a single treatment.