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Objective: The degree of color change and the dental sensitivity associated with the use of different concentrations (10%, 15%, and 20%) of carbamide peroxide every night for 6 months was evaluated in tetracycline-stained teeth., Method and Materials: Fifty-nine subjects were shown how to place two different concentrations of carbamide peroxide in the custom trays with reservoirs. For a period of 6 months, the patients were to insert the tray every evening before retiring. Patients returned in 1 and 2 weeks and at 1, 2, 3, 4, 5, 6, 7, 8, and 9 months for evaluation of the degree of color change by subjective shade matching and by photographic means. Sensitivity of hard or soft tissues was self-reported., Results: Fifty-two subjects attended more than 90% of the recalls. A colorimeter was used to convert shade guide tabs to Commission Internationale de l'Eclairage color spaces (CIELAB). The most rapid whitening occurred in the first month. At 3 and 9 months, 91% and 85% of the subjects, respectively, were at least "a little pleased" with the results of the bleaching. In the professional evaluation, 90% of the teeth were deemed to have an excellent or satisfactory esthetic result. The higher the concentration of carbamide peroxide, the more rapidly the lightness value and color difference changed. There was no difference among the three concentrations in resulting gingival sensitivity. Patients experienced less tooth sensitivity with 10% gel than they did with 15% and 20% gels., Conclusion: Bleaching with 10%, 15%, and 20% carbamide peroxide is effective for removing tooth staining caused by tetracycline. The 10% concentration has the most advantages and the fewest disadvantages.

Objective: The purpose of this study was to evaluate the degree of color change, any rebound effect, and sensitivities associated with using 2 different concentrations of carbamide peroxide in vivo., Method and Materials: Twenty-five subjects used 10% and 15% agents in trays for 14 days on different sides of their maxillary arches. Subjects returned in 3 days and at 1, 2, 3, and 6 weeks for evaluation of color change and rebound effect. Shade matching, photographic means, and a colorimeter were used for evaluation. Subjects self-reported gingival and tooth sensitivity on a scale of 1 (no sensitivity) to 5 (severe sensitivity)., Results: After 2 weeks, delta L*, delta a*, delta b*, delta E* and delta shade guide rank means for the 10% whitening agent were 6.50, -1.37, -4.63, 8.79, and -15.40, respectively; for the 15% agent, they were 8.72, -1.63, -5.90, 11.03, and -16.59, respectively. After 6 weeks, delta L*, delta a*, delta b*, delta E*, and delta shade guide rank means for the 10% whitening agent were 3.04, -0.99, -3.19, 5.13, and -13.13, respectively; for the 15% agent, they were 3.48, -1.01, -3.60, 5.58, and -13.65, respectively. Means for gingival sensitivity were 1.18 and 1.21 for the 10% and 15% agents, respectively; means for tooth sensitivity were 1.21 and 1.26 for the 10% and 15% agents, respectively., Conclusion: All 3 methods of evaluation revealed a significant difference in the tooth lightness achieved by 10% and 15% products at 2 weeks but no significant difference at 6 weeks. No statistically significant difference was found in gingival or tooth sensitivity.

Objective: The purpose of this study was to determine the degradation of 10% carbamide peroxide within the first hour of use and the effect of pellicle on the degradation of carbamide peroxide in vivo., Method and Materials: Fifteen subjects were assigned to wear nightguard trays filled with bleaching gel for 0.5, 2.5, 5.0, 10.0, 20.0, 40.0, and 60.0 minutes under 2 conditions: (1) subjects did not receive a prophylaxis before each bleaching treatment (pellicle was assumed to be present on the tooth surface); and (2) subjects received prophylaxis to remove pellicle from the tooth surface. At each evaluation time, 3 types of sample were collected: (1) a "grab sample," a sample of gel taken with a spatula from the reservoir of the tray on the maxillary right central incisor; (2) the remaining gel from the tray; and (3) the remaining gel scraped from the teeth. The collected gel samples were analyzed for the amount of peroxide using the United States Pharmacopeia-accepted method. Subjects were asked not to swallow the saliva during treatment but to expectorate into a beaker. The collected saliva was analyzed to determine the amount of peroxide. This sample represented the approximate amount of peroxide that subject would ingest during treatment., Results: Pellicle did not affect the degradation of carbamide peroxide for the teeth or grab samples. The degradation of carbamide peroxide was exponential, except during the first 5 minutes, when the degradation rate was much higher. The saliva collected from subjects during use of the bleaching tray revealed an average of 2.1 mg of carbamide peroxide for 1 hour of bleaching treatment., Conclusion: The degradation rate is not affected by the removal of the pellicle.

Objective: A 6-month, double-blind study was undertaken to assess the efficacy and safety of a 10% carbamide peroxide gel designed for at-home tooth bleaching., Method and Materials: Sixty patients were randomized into two equal subgroups balanced by age, gender, and oral health status. Shade guide measurements, color transparency photographs, and colorimeter readings were taken and evaluated at baseline and 1, 2, 3, 6, 12, and 24 weeks. The active phase of treatment lasted 14 days., Results: At 22 weeks postbleaching (week 24 of the study), patients receiving the active agent had a 14.1 rank order difference in the shade guide from baseline, and 66% had a clinically observable color change as determined by photographic assessment. They also had a measurable, statistically significant color change from baseline to 6 months of delta E* = 5.0. The tooth color of maxillary incisors stabilized at week 6 and maxillary canines at week 12. The mean color change lost from weeks 2 to 24 was 45% (in delta E*). Transient tissue and tooth sensitivity, noted in some patients, resolved after treatment was completed., Conclusion: The product tested is an effective and safe tooth-whitening agent.

Three restorative materials used for cervical erosion /abrasion lesions were evaluated clinically after 10 years. Thirty adult patients with at least four cervical lesions received one restoration of each of Ketac-Fil, finished immediately, Ketac-Fil, finished after a delay, Chelon-FIl (all glass-ionomer cements), and Cervident (a resin composite). Restorations were placed without any tooth preparations. Eighteen patients returned for their 10-year examinations. Two experienced examiners provided the periodic evaluations. Complete retention at 10 years was 83% for Ketac-Fil, finished immediately; 78% for Ketac-Fil, finished after a delay; 67% for Chelon-Fil; and 17% for Cervident. All three glass-ionomer restorative materials exhibited statistically significantly greater retention that did Cervident. When a noninvasive procedure is desired, glass-ionomer materials are the restorative material of choice for abrasion/erosion lesions because of their long-term retention values.