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At least 127 records · Page 7Linked to original sources

A safety study in vitro for the effects of an in-office bleaching system on the integrity of enamel and dentine.

OBJECTIVE: The aim of this study was to investigate safety concerns with bleaching procedures by studying the effects of a high concentration hydrogen peroxide (HP) in-surgery bleaching product on enamel and dentine. METHOD: Flat enamel and dentine samples embedded in epoxy resin were prepared from human third molar teeth. Erosion of enamel: groups of enamel samples were treated with 35% HP then citric acid (CA) or brushing with toothpaste or CA alone and water alone. Enamel Loss was measured using a profilometer. Abrasion/erosion of dentine: groups of dentine specimens were treated as follows: Group 1--brushed with water for 30 min. Group 2--brushed with 35% HP for 30 min. Group 3--power bleached for 30 min and then Group 4--brushed with toothpaste for 1 minute. Group 5--water soaked for 30 min followed by brushing with toothpaste for 1 min. Group 6--orange juice soaked for 30 min followed by brushing with toothpaste for 1 min. Treatment effects were measured using a profilometer. Hardness tests: enamel and dentine specimens were hardness tested using a Wallace indenter prior to and post bleaching. Scanning Electron Microscopy: enamel and dentine specimens were taped and the exposed tissue treated with 35% HP and then studied under scanning electronmicroscopy (SEM). RESULTS: Enamel erosion: bleaching enamel samples had no measurable effect on enamel. Pre-bleaching had no significant effect on subsequent CA erosion or brushing. Abrasion/erosion of dentine: no significant differences were found between treatments 1-5 with little change from baseline detected. Orange juice (Group 6) produced considerable and significantly more erosion than other treatments. Hardness tests: there were no significant changes in hardness values for enamel and dentine. SEM: there was no evidence of any topographical changes to either enamel or dentine. CONCLUSION: Using one of the highest concentrations of HP for tooth bleaching procedures and maximum likely peroxide exposure, there was no evidence of deleterious effects on enamel or dentine. It must be assumed that studies which reported adverse effects on enamel and or dentine of bleaches reflect not the bleach itself but the pH of the formulation used.

Beverages↗

Role of saliva and salivary components as modulators of bleaching agent toxicity to human gingival fibroblasts in vitro.

Mild oxygenating agents generating H2O2 are used for effective at-home tooth bleaching, but can cause gingival ulcers in some patients. There are concerns about the possible pathological effects of relatively long-term exposure of oral tissues to bleaching agents. Previous work in our laboratory showed that a bleaching agent, which generates approximately 3% H2O2 from carbamide peroxide, was toxic to human gingival fibroblasts in vitro, but that the toxicity was abolished by treatment with the H2O2-destroying enzyme catalase. The purpose of the present study was to determine if whole saliva, the salivary enzyme lactoperoxidase (LP) (which, like catalase, removes H2O2), or salivary mucin protected fibroblasts from bleaching agent toxicity. The cells were exposed to 0.05% agent with or without saliva, LP, mucin or catalase (as a positive control based on our previous study) and assessed for effect on viability/morphology (by microscopic observation), proliferation (by [3H]-thymidine incorporation), and the production of fibronectin (FN) and type I collagen (by ELISA). While the bleaching agent at 0.05% caused cell death, the cells appeared viable and morphologically normal when treated with the bleaching agent and LP (> or = 0.1 microM), saliva LP, and catalase from agent inhibition of proliferation (P < or = 0.04) and FN production (P < or = 0.01). Mucin had statistically insignificant or no protective effect as assessed by the above parameters. Treatment with saliva, LP, mucin, and catalase gave complete or partial protection from agent-inhibition of collagen production (P < or = 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

Catalase↗

Influence of the duration of treatment using a 10% carbamide peroxide bleaching gel on dentin surface microhardness: an in situ study.

This in situ study evaluated the influence of two home-use tooth bleaching regimes (1 hour/day and 7 hours/day) using 10% carbamide peroxide (Nite White Excel 2Z) on the surface microhardness of dentin over a 21-day period. Nine blocks of dentin derived from the teeth of subjects, each with at least two thirds molar in need of extraction, were obtained from the cervical region and submitted to surface-hardness analysis (Shimadsu HMV/2000), fixed to an intraoral palate device fabricated for each subject, and positioned (3 left side, 3 right side, 3 center) according to experimental group. During the bleaching period, casts bearing the whitening agent were applied to the blocks for 7, 1, and 0 hours, respectively (7 left side, 3 right side, 0 center). After the treatment period, the specimens were once again submitted to microhardness analysis, using the same equipment as before, and then analysis of variance and the Scheffé test were applied to the mean differences between the initial and final evaluations. The results demonstrated that the statistical difference between the 1-hour and 7-hour groups was not significant. However, the 7-hour group, when compared with the control group, demonstrated statistically significant differences with a reduction in microhardness. Despite the occurrence of mineral loss in the 1-hour and 7-hour groups, this difference was only 3.1% and 5.4%, respectively, which allows one to conclude that these values probably have no clinical significance.

Adolescent↗

Clinical trials on the use of whitening strips in children and adolescents.

Vital tooth bleaching is becoming increasingly popular. Both professionally supervised and over-the-counter tooth whitening systems are being utilized. Recently, a tooth whitening system became available where a gel containing hydrogen peroxide was delivered via a flexible polythene strip. Three clinical trials were conducted using whitening strips to treat tooth discoloration on 132 children and adolescents. Results indicated the strip bleaching system to be an effective means for tooth whitening. Minimal sensitivity was associated with this whitening system, with most of the reported sensitivity being noted as mild. All sensitivity was relieved upon discontinuance of the whitening agent.

Adolescent↗

Toxicity of two carbamide peroxide products used in nightguard vital bleaching.

This study evaluated the effects of two generic classes of 10% carbamide-peroxide (CP) oxygenating agents (currently under clinical assessment for nightguard vital tooth bleaching) for lethality and genetic mutation after oral administration to mice, and for cellular cytotoxicity to mouse fibroblasts in vitro. The single dose LD50 values for a non-carbopol-containing CP (Gly-Oxide) and a carbopol-containing CP (Proxigel) in mice were found to be 143.8 mg/kg and 87.2 mg/kg, respectively. Genotoxicity, as measured by the Mouse Micronucleus test for mutagenicity, was negative for both 10% CP agents in comparison with positive and negative controls. Cytotoxicity as measured in the L929 fibroblast lysis assay resulted in 50% killing of L929 fibroblasts at 0.62 for the non-carbopol-containing CP and 1.88 mmol/L for the carbopol-containing CP. Both 10% CP agents were compared with seven widely-used dental products in the L929 fibroblast lysis assay and found to be no more toxic than these products.

Analysis of Variance↗

The effect of artificial saliva on the rheological properties of tooth whitening systems.

This work was undertaken to explore the effect of saliva addition on the rheological properties of two contrasting tooth bleaching systems, one of which was a paste (Colgate Platinum) and the other a gel (Zaris, 3M ESPE). Using a dynamic stress rheometer with cone and plate geometry, it was shown that addition of artificial saliva reduced the apparent viscosity of each material. However, in some cases this was accompanied by an increase in elasticity. It is suggested that saliva may not have a deleterious effect on the ability of the materials to remain in the bleaching tray.

Dentifrices↗

The Food and Drug Administration and its influence on home bleaching.

The era of bleaching vital teeth has captured the attention of the dental profession, the public, the media, and the government. This method, using a custom-fitted mouthguard and a carbamide peroxide solution, is known as home bleaching, matrix bleaching, nightguard vital bleaching, passive bleaching, and dentist-prescribed-home-applied bleaching. Recent action of the US Food and Drug Administration and continued research and clinical experience in the area have provided favorable and unfavorable information about the variations of the technique. This article discusses these variations, with the general conclusion that the technique of vital tooth bleaching, when administered by a dentist using a custom-fitted mouthguard, is as safe as many other routinely performed dental procedures.

Carbamide Peroxide↗

Tooth whitening in children.

Although there are several case reports of vital tooth bleaching in children, there is limited clinical trial evidence of the safety or efficacy of this practice. Accordingly, a new clinical trial was conducted to evaluate the effects of 2 different bleaching systems, a 6.5% hydrogen peroxide strip system and a 10% carbamide peroxide tray system, in a population of preteens and teens. A total of 106 volunteers, aged 11 to 18 years, took part in this 8-week study. Patients were randomized by a ratio of 2:1 to the strip or tray groups, with each group treating the maxillary arch first and then the mandibular arch for 4 consecutive weeks each. Individuals assigned to the strip group used the system twice daily for 30 minutes (a total of 56 contact hours over the 8-week study). Those assigned to the tray group used that system overnight (approximately 448 contact hours). Digital images were obtained at baseline and after every 2-week treatment period. Average tooth color was determined in L*, a*, b* color space, where L* indicated lightness, a* indicated red-green, and b* indicated yellow-blue. Both systems significantly whitened teeth (P < 0.0001). While there were no significant differences between groups with respect to the primary whitening response (delta b*) on the maxillary teeth, 4 weeks of overnight treatment with the 10% carbamide peroxide tray (approximately 224 contact hours) yielded statistically significant whitening (P < 0.05) on the mandibular teeth compared with the 6.5% hydrogen peroxide strip used for 28 hours. Both tooth-whitening systems had similar sensitivity/irritation reported after instructed use. This research demonstrates that tooth whitening in teens may be safely accomplished using either the short-contact-time hydrogen peroxide bleaching strips or the overnight carbamide peroxide tray systems tested in this study.

Adolescent↗

State-of-the-art in restorative aesthetic dentistry - 1993: an overview.

Major changes have taken place in the profession of dentistry during the last three decades. In this overview, the author summarizes developments in vital tooth bleaching, resin bonding in the anterior and posterior Class II locations, veneers, inlays/onlays, all-ceramic crowns, and sonic cementation. An up-to-date knowledge of the state-of-the-art in the profession of dentistry is the learning objective of this overview.

Crowns↗

External cervical resorption after bleaching a pulpless tooth.

A tooth with cervical resorption possibly caused by an internal bleaching technique was treated with calcium hydroxide. This case had characteristics in common with the other seven cases that have been described in the literature. Several possible treatment methods are discussed, along with the speculation that internal bleaching of tetracycline-discolored teeth may lead to cervical resorption.

Adult↗

Comparative tooth whitening efficacy of 18% carbamide peroxide liquid whitening gel using three different regimens.

OBJECTIVE: Recently, a novel paint-on liquid whitening gel--Colgate Simply White Clear Whitening Gel--which contains 18% carbamide peroxide, has been developed as a self-administered tooth bleaching system. The purpose of the present study was to determine the efficacy and safety of this product using alternate exaggerated or simplified treatment regimens. METHODOLOGY: This was a three-week clinical trial using a parallel, double-blind, stratified protocol with three different instructions for application: 1) twice-daily, no air-drying, and 15 minutes without eating/drinking; 2) three times daily, 30-second air-drying and 30 minutes without eating/drinking; or 3) four times daily, 30-second air-drying and 30 minutes without eating/drinking. One-hundred and twenty (120) healthy volunteers were balanced into three equal groups based on shade scores (A3 or darker). Clinical evaluations (shade guide, oral tissue health, gingival index and visual analog sensitivity score) were performed on each group at baseline and weekly for the next 21 days. At the conclusion of the study, a survey of the subjects' opinions on their assigned product regimen was also conducted. RESULTS: Subjects who used Colgate Simply White Clear Whitening Gel three and four times daily achieved the greatest shade improvement (5.88 +/- 1.53 shades, and 5.57 +/- 1.54, respectively). However, these values were only about one shade better than the value observed for the more convenient, twice-daily, "no-dry" regimen (4.51 +/- 1.77 shades), though they were statistically significant (p < 0.05). The result for the four-times daily protocol was not statistically different from the three-times group. Also, no differences were observed between the groups concerning oral tissue health, gingival index or tooth sensitivity, and no adverse effects were observed or reported regardless of the regimen used. Surveys completed by the subjects showed that those who used the twice-daily, "no-dry" regimen found the product to be the easiest to use, the most comfortable and the most pleasant tasting. CONCLUSION: It can be concluded from the clinical data that three or four applications of Colgate Simply White Clear Whitening Gel per day provided better efficacy. In addition, the use of the whitening gel twice daily, even without "dry time" and only 15 minutes without eating/drinking, yielded results that were comparable to previously reported results using the original on-label directions. The potential additional benefit to the "simplified regimen" is that it was perceived to be the most convenient and comfortable. The use of Colgate Simply White Clear Whitening Gel up to four times daily for up to three weeks is also safe, and the tendency of abusing the product with more frequent daily use may be deterred by the inconvenience reported by the study subjects.

Adult↗

Influence of dental biofilm on release of mercury from amalgam exposed to carbamide peroxide.

Tooth bleaching is a popular procedure in modern aesthetic dentistry. Bleaching agents may affect amalgam restorations by altering the release of mercury. The aim of this study was to explore the effect of biofilm-coated amalgam restorations on the release of mercury in the presence of carbamide peroxide. Samples of SDI and Valliant amalgams were submerged for either 14 days or 7 months in buffered KCl after which they were coated with saliva, bacteria, and polysaccharides. The samples were exposed to 10% carbamide peroxide (CP) for 24 h. The amount of mercury released was examined for 120 h. Results showed that most of mercury release occurred within the first 24 h, after which the release rate decreased sharply. After 120 h the release of mercury from the tested samples was minimal and similar to the control group. The presence of biofilm coating on the amalgam samples did not induce the release of mercury but tended to reduce mercury release into the surrounding environment. CP induces the release of mercury from amalgam samples. However, the presence of biofilm did not prevent large amounts of mercury release from amalgam coated with biofilms and exposed to CP. This study indicates that dental biofilm may retard the release of mercury from amalgam restorations.

Biofilms↗

A clinical study of nightguard vital bleaching.

This double-blind, randomized, controlled clinical trial was designed to evaluate the efficacy and soft tissue effects of nightguard (mouthguard) vital bleaching. Subjects were assigned to one of two treatment groups, overnight (insertion of mouthguard at bedtime) or 3-hour (replenishment of test solution at hourly intervals for a total of 3 hours exposure daily). The experimental solutions included two products that are specifically designed for tooth bleaching, one product that is marketed as an oral antiseptic, and a control solution (glycerin). Each subject participated for a 3-week period. Tooth color analysis (shade determination) was done at baseline and the end of the treatment. Gingival and Plaque Indices were recorded at baseline and at the end of each week of study. Results indicated that the bleaching treatment was effective in most cases and caused no tissue inflammation or significant tooth sensitivity. The mean Gingival and Plaque Indices were generally lower (denoting improvement) at the end of treatment. Patient satisfaction with the procedure was high.

Analysis of Variance↗

A clinical evaluation of carbamide peroxide and hydrogen peroxide whitening agents during daytime use.

BACKGROUND: Vital tooth bleaching for esthetic reasons has gained in popularity during the last few years. However, few studies have investigated the efficacy of daytime bleaching products. The purpose of this double-blind in vivo study was to evaluate the efficacy of 20 percent carbamide peroxide, or CP, and 7.5 percent hydrogen peroxide, or HP, during daytime use. The degree of color change, any color relapse, and tooth or gingival sensitivity were evaluated. METHODS: Twenty-four patients participated in this study. The bleaching gels were randomly applied to the right and left maxillary anterior teeth. Patients were shown how to place the two bleaching agents in a custom tray for one hour, twice a day for two weeks. Patients returned in one, two, three, six and 12 weeks for color evaluation with the colorimeter and shade guides as well as to have color slide photographs taken. The authors evaluated sensitivity by asking the patients to record daily for 21 days any tooth or gingival sensitivity they experienced. RESULTS: Use of the 20 percent CP resulted in significantly more lightness than the 7.5 percent HP during the first 14 days of the study, but at the end of the study, there was no significant difference between products with regard to tooth lightness. In addition, the authors found no statistically significant difference between products with regard to gingival or tooth sensitivity. CONCLUSIONS: Both CP and HP are effective at-home bleaching agents when daytime bleaching is preferred. CLINICAL IMPLICATIONS: Dentists who choose to use daytime bleaching can select either CP or HP.

Adult↗

In vitro tooth color change with repeated bleaching.

The interest of patients in vital tooth bleaching has created a demand for treatment. However, few objective data are available to help determine the number of bleaching appointments necessary and the lightening that can be expected. The purpose of this study was to measure color changes in bleached extracted teeth and compare these to control groups. Group A was etched and bleached with 35% stabilized hydrogen peroxide. Group B was treated the same as group A, but the bleaching solution was replaced with distilled water. Group C was not treated, but was stored in water. Mean color difference after one treatment was 3.33 for group A, 1.67 for group B, and 0.48 for group C. After six treatments, the overall color difference was 3.82, 2.41, and 1.38 for groups A, B, and C, respectively (P less than .01). Color changes beyond those found after the first treatment were small, suggesting that there was little benefit in repeated bleachings under the conditions of this study.

Acid Etching, Dental↗