In the present study, we evaluated the bleaching effect and the regression of the tooth color when 23% and 40% hydrogen peroxide vital bleaching agent were used.
Twenty patients attended in this study. TiON in Office （23 ％ H2O2, Ti） and Opalescence Boost PF40% （40% H2O2, Op） were used as bleaching agents according to the manufacturer’s instructions. L*, a*, b* were measured with a spectrophotometer before bleaching, immediately after bleaching, 14, 30, 90, 180 , and 360 days after bleaching. 1） The differences in L*, a*, and b* before and after bleaching at each measurement, 2）Δ E*ab value before bleaching as the baseline, and 3） daily changes in L*, a*, and b* from immediately after bleaching until after 360 days were calculated. The data was analyzed by Two-way ANOVA at P<0.05.
After bleaching by Ti and Op, L* was higher, and a* and b* were lower than before bleaching. There were no significant difference between Ti and Op. Regression of color occurred early after treatment, however, it was very gently. The E*ab value had no significant difference between after bleaching and after 360 days. The daily changes in L*, a*, and b* after bleaching showed differing in peaks from 0 to 14 days for Ti and 14 to 30 days for Op, but both agents remained stable at 30 days after bleaching.
The results suggest that Ti and Op have enough bleaching effects, while the stability of color after bleaching and the regression slightly differ.
In the initial periodontal therapy, SRP is performed on the subgingival root surface． Recently, Er:YAG lasers which are light in thermal denaturation of tissues and shows high absorption of water, are used for pathological root debridement.
By using the Er:YAG laser, we had a case in which the maxillary anterior teeth with severe bone resorption were preserved for one and half years.
An 81 - year - old man attended the clinic with complaints of discomfort in the maxillary anterior teeth part．A periodontal pocket exceeding 10 mm at 21 and remarkable bone resorption over the apex were observed and it was diagnosed as a periodontal hopeless tooth．However, since the patient strongly desired the preservation of a the 21 tooth, SRP was performed by using the Er:YAG laser for the tooth．As a result, an improvement of the deep periodontal pocket and a decrease of Bleeding On Probing （+） sites were observed．In this case, it was shown that the Er:YAG laser is effective for reducing inflammation even for periodontal hopeless teeth.