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At least 19 recordsLinked to original sources
PubMed2000

Rheological characteristics of tooth bleaching materials.

Tooth bleaching materials need to flow easily on insertion but should have high viscosity at low stresses to stay in place on the teeth. Some degree of elasticity may also aid retention on the teeth thereby maximizing efficacy. The present work was undertaken to study the comparative rheology of three tooth bleaching systems: two gels (Opalescence, Ultradent; Perfecta Trio, American Dental Hygienics) and a paste (Colgate Platinum, Colgate). A dynamic stress rheometer (Rheometrics Scientific) with cone and plate geometry was used, with the materials maintained at 37.0+/-0.1 degrees C with a vapour hood to minimize volatilization. Stress creep and recovery experiments were carried out. Steady shear viscosity for all three systems was high (>10(6) Pa s(-1)) for stresses <20 Pa. Between 100 and 200 Pa stress, all three materials showed a large drop in viscosity and flowed readily. The recovery portion of the data showed a marked difference where the elasticity of the gels was nearly two orders of magnitude higher than that of the paste. It was concluded that all materials would flow readily on insertion into the mouth and all have desirable high viscosity at low stress, but the paste material had the lowest elasticity. The effect of elasticity on performance needs to be determined clinically.

Carbamide Peroxide↗
PubMedDate not supplied

[Histological aspects of tooth bleaching technics].

The chemical principles of tooth bleaching are detailed in order to analyze scanning microscopy data obtained following internal and external bleaching tooth bleaching appears harmless to the enamel structure providing no etching is applied prior to bleaching. Previous enamel undermining appears to increase the porosity along preexisting cracks. Internal bleaching gives way to enamel and dentinal demineralization, which is of particular importance at the dento enamel junction. The biological effects of bleaching on dental hard tissues must be viewed in light of the clinical indications for these procedures.

Adult↗
PubMed1994

Considerations and variations of dentist-prescribed, home-applied vital tooth-bleaching techniques.

Tooth-bleaching procedures became widely available with the 1989 introduction of a dentist-home technique. Over-the-counter home systems were put on the market shortly thereafter, but safety concerns led to a sales ban by the Food and Drug Administration (FDA) in 1991. That ban has been lifted while companies continue to supply information to the FDA. Information on bleaching safety has often been skewed because the high 35% hydrogen peroxide concentration used in the dentist-office procedures has sometimes been compared out of context with dentist-home formulas with 10% to 15% carbamide peroxide or 1% to 10% hydrogen peroxide. Earlier studies have also failed to put the risk level of tooth bleaching into perspective with other routine dental procedures. More recent studies show that 10% carbamide peroxide is safe when appropriately administered. Haywood does state that there is a risk level in any type of bleaching, and that the dentist-home system provides the best way to minimize the risk because the dentist can: (1) diagnose any problems or special needs; (2) plan appropriate treatment; and (3) fabricate, fit, and adjust the prosthesis used to apply the formula. A success rate of 96% (excluding tetracycline stain) has been achieved. Currently, most marketed systems use a carbamide peroxide in a thickened glycerin base. A new product is being introduced with 10% carbamide peroxide, a peroxide stabilizer, a thickener, and tooth-cleansing technology ingredients.

Carbamide Peroxide↗
PubMed2003

Tooth bleaching--a critical review of the biological aspects.

Present tooth-bleaching techniques are based upon hydrogen peroxide as the active agent. It is applied directly, or produced in a chemical reaction from sodium perborate or carbamide peroxide. More than 90% immediate success has been reported for intracoronal bleaching of non-vital teeth, and in the period of 1-8 years' observation time, from 10 to 40% of the initially successfully treated teeth needed re-treatment. Cervical root resorption is a possible consequence of internal bleaching and is more frequently observed in teeth treated with the thermo-catalytic procedure. When the external tooth-bleaching technique is used, the first subjective change in tooth color may be observed after 2-4 nights of tooth bleaching, and more than 90% satisfactory results have been reported. Tooth sensitivity is a common side-effect of external tooth bleaching observed in 15%-78% of the patients, but clinical studies addressing the risk of other adverse effects are lacking. Direct contact with hydrogen peroxide induced genotoxic effects in bacteria and cultured cells, whereas the effect was reduced or abolished in the presence of metabolizing enzymes. Several tumor-promoting studies, including the hamster cheek pouch model, indicated that hydrogen peroxide might act as a promoter. Multiple exposures of hydrogen peroxide have resulted in localized effects on the gastric mucosa, decreased food consumption, reduced weight gain, and blood chemistry changes in mice and rats. Our risk assessment revealed that a sufficient safety level was not reached in certain clinical situations of external tooth bleaching, such as bleaching one tooth arch with 35% carbamide peroxide, using several applications per day of 22% carbamide peroxide, and bleaching both arches simultaneously with 22% carbamide peroxide. The recommendation is to avoid using concentrations higher than 10% carbamide peroxide when one performs external bleaching. We advocate a selective use of external tooth bleaching based on high ethical standards and professional judgment.

Animals↗
PubMed1992

Vital tooth bleaching: review and current status.

Vital tooth bleaching refers to the clinical application of a chemical solution to a tooth surface in order to achieve a lightening effect. This article reviews the available literature to address the following questions: What are the methods of vital bleaching? How does vital bleaching work and is it effective? What effects are there on the teeth, dental restorative materials, soft tissues and systemic health? The techniques used in the application of dentist-applied and patient-applied bleaching systems are described. Generally, vital tooth bleaching has been found to be effective, however, relapse does occur. The literature suggests that bleaching agents may have transient effects on the tooth itself, and may affect some dental materials. Soft tissues exposed to hydrogen peroxide for prolonged periods show changes consistent with inflammation or hyperplasia. Hydrogen peroxide may also potentiate the carcinogenic effect of known carcinogens. However, more clinically relevant studies are needed. Until long-term safety data becomes available, the dental practitioner should approach the use of in-home bleaches with caution. The U.S. Food and Drug Administration (FDA) recently classified these products as "new drug." However, dentist-applied bleaching gel systems are a viable alternative and deserve further consideration. They are simple to use, require little armamentarium, and limit the exposure of the bleaching agent to the teeth only. Vital tooth bleaching refers to the clinical application of a chemical solution to a tooth surface in order to achieve a lightening effect. There was a resurgence of interest in vital bleaching with the recent introduction of the in-home bleaching technique.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbamide Peroxide↗
PubMed1995

Acute toxicity of carbamide peroxide and a commercially available tooth-bleaching agent in rats.

Previous studies have indicated that tooth-bleaching agents contain potentially hazardous chemicals. The present study evaluates the acute toxicity of a commercially available tooth-bleaching agent and carbamide peroxide, which is the active bleaching ingredient. Rats were dosed by stomach gavage, i.e., via a stomach tube, with 5, 15, and 50 mg carbamide peroxide/kg body weight and 150 and 500 mg tooth-bleaching agent/kg body weight, corresponding to 15 and 50 mg carbamide peroxide/kg body weight. Animals were killed after either one or 24 h. Autopsies were performed, and the distal part of the esophagus and the stomach were removed and processed for light microscopy investigation. Liver and kidney were evaluated histologically in animals killed after 24 h. Carbamide peroxide gave dose-dependent ulcerations of the gastric mucosa, with the 15 mg/kg body weight as the lowest observed effect level. The lesions were clearly visible after one h and seemed to be healing after 24 h. The ulcerations of the gastric mucosa were more pronounced after exposure to the tooth-bleaching agent than those observed after a comparable dose of carbamide peroxide. This may be attributed to the hydrophobic gel and the content of a carbopol (which increases the tissue adherence and retards the release of oxygen) in the bleaching agent. No apparent injury was observed in livers and kidneys. An exposure limit based on the lowest observed effect level (15 mg carbamide peroxide/kg body weight) and a safety factor of 100 were established and utilized in a risk assessment which indicated that daily human exposure during a bleaching procedure may come close to or even exceed this limit.

Acrylic Resins↗
PubMed1998

Making a clinical decision for vital tooth bleaching: at-home or in-office?

The dramatic increase in public demand for esthetic dentistry and tooth bleaching has encouraged development and resulted in new products and eltasdeltaues. Vital tooth bleaching, including in-office bleaching and at-home bleaching, has been adopted as an effective and safe method for whitening natural dentition. Although most dentists prefer at-home bleaching, nearly one third use in-office bleaching. Continuous improvements in bleaching products and delivery systems have made in-office bleaching more practical and predictable. This article discusses the practical applications of vital tooth bleaching, as well as the advantages and disadvantages of each method.

Adult↗
PubMed1998

Tooth bleaching using peroxide-containing agents: current status of safety issues.

During the last 10 years, at-home tooth bleaching using peroxide-containing agents has quickly become well accepted. It is one of the most popular cosmetic dental procedures for whitening teeth. Although there are few disputes regarding their efficacy, concerns and debates have continued regarding the safety of peroxide-containing tooth bleaching agents. Potential carcinogenicity and genotoxicity of the peroxides used in bleaching agents are the two most persistent and controversial issues. This article reviews and discusses available information on carcinogenicity and genotoxicity of hydrogen peroxide and the potential risks associated with the use of peroxide-containing bleaching agents. Clinical studies reported after the 1996 international symposium on responses of oral tissues to peroxide-containing bleaching agents are also reviewed. Overall evidence supports the conclusion that the proper use of peroxide-containing at-home tooth bleaching agents is safe. However, potential adverse effects may occur in inappropriate applications, abuses, or the use of inappropriate products. At-home tooth bleaching should be monitored by dental professionals to maximize the benefits while minimizing potential risks.

Animals↗
PubMedDate not supplied

Is home tooth bleaching gel cytotoxic?

Tooth whitening systems are widely used clinically and for home usage. The aim of this study was to determine the effects of two bleaching gels, each containing 10 percent and 15 percent carbamide peroxide, respectively, a 'bleaching gel' without carbamide peroxide, and carbamide peroxide alone on the viability of human endothelial cells in vitro in comparison with culture medium that acted as a negative control. The incubation period used was 30 minutes. A colorimetric viability assay (MTT assay) was employed. The results showed that the gel without carbamide peroxide is not cytotoxic compared to the negative control, while carbamide peroxide on its own and 10 percent and 15 percent carbamide peroxide bleaching gels were cytotoxic, but there were no significant differences (p greater than 0.05) among these latter three test groups. These data indicate that 10 percent and 15 percent carbamide peroxide bleaching gels are cytotoxic and that carbamide peroxide is the component responsible for this cytotoxic effect. This paper also discusses why this in vitro cytotoxic effect appears not to be significant in vivo.

Analysis of Variance↗
PubMed2002

Effect of nonvital tooth bleaching on resin/enamel shear bond strength.

PURPOSE: This study evaluated the effect of nonvital tooth bleaching on shear bond strength (SBS) of the composite resin/bovine enamel interface at different periods of time after bleaching. MATERIALS AND METHODS: Three hundred twenty teeth were randomly divided into four groups according to bleaching agent: SPH: sodium perborate and 30% hydrogen peroxide; SPW: sodium perborate and distilled water; CP: 37% carbamide peroxide; and PLA: distilled water (placebo). The bleaching agents in the pulp chambers were replaced every 7 days for 4 weeks. For SBS testing, each of these groups was randomly divided into four subgroups (n = 20) according to the postbleaching periods of time: 0 (baseline), 7, 14, and 21 days. At the respective time, enamel slabs were embedded in polyester resin and flattened. Composite resin cylinders (Z100/Single bond, 3M) were bonded to the enamel surface and subjected to the SBS test using a universal testing machine. RESULTS: The ANOVA and Tukey's test (alpha = 0.05) showed statistically significant differences (expressed by different letters) among the bleaching agents only at follows: PLA (a), CP (ab), SPW (ab), and SPH (b). The SPH group, showing the lowest mean value, differed significantly from the control group. At 7, 14, and 21 days, no significant differences were observed. CONCLUSION: Nonvital tooth bleaching affected the resin/enamel SBS values when sodium perborate mixed with 30% hydrogen peroxide was used.

Analysis of Variance↗
PubMed1994

Tooth bleaching for children and teens: a protocol and examples.

Even though there has been much interest in dental bleaching in recent years, little has been reported about patient-applied carbamide peroxide tooth bleaching for children and adolescents. This technique article describes "at home" tooth bleaching for young patients and offers a proven protocol for the procedure. Representative cases are documented with pretreatment and posttreatment photographs. Bleaching in conjunction with enamel microabrasion is also reviewed.

Adolescent↗
PubMedDate not supplied

Vital tooth bleaching in dental practice: 2. Novel bleaching systems.

UNLABELLED: This paper describes some of the novel commercial approaches to tooth bleaching. Known as 'direct-to-consumer' products there are two main systems available, one employing coated, cellulose strips and the other a paint-on gel. A further development is the production of dentifrices that contain active hydrogen peroxide, made possible by the use of dual chambered tubes. Each of the systems is described and demonstrated and an overview of the research supporting their safe, effective use is presented in each case. It is likely that our patients have access to these products and, hence, it is important that we are aware of their strengths and weaknesses. CLINICAL RELEVANCE: The systems described within this paper are available for sale in Europe and over the internet. Patients may well be using, or planning to use, them and may ask for professional advice.

Age Factors↗
PubMed1997

Toxicological considerations of tooth bleaching using peroxide-containing agents.

Peroxides have been used for tooth bleaching for more than 100 years. Besides those administered in the dental office, agents for at-home bleaching have become popular. To date, there have been no published significant adverse effects caused by dentist-monitored, at-home bleaching agents. But potential risks, particularly those associated with abuses or the use of inappropriate products, need to be recognized. Using an ADA-accepted, at-home bleaching agent under a dentist's supervision is recommended to minimize risks while achieving desired benefits.

Animals↗
PubMed1991

Tooth bleaching: its effect on oral tissues.

After investigating the literature, we suggest these guidelines for tooth bleaching: If bleaching solutions of high concentration are used, prevent accidental exposure of gingival tissues to the solutions by use of a rubber dam. If using lower concentrations of bleaching solutions, avoid long-term exposures to gingival tissues. To maintain pulp vitality, keep bleaching time and temperatures to a minimum. Check teeth for exposed dentin and enamel fractures. Advise patients that thermal sensitivity may occur after the bleaching procedure and may persist for several days. Prescribe premedication with an anti-inflammatory drug, when necessary. Avoid bleaching the cervical area of the tooth by covering the area with a base to avoid cervical resorption. Avoid dentin exposure by noting that abrasive bleaching techniques can remove significant amounts of enamel. Take special care when bleaching enamel--especially near the cervix of the tooth, where the enamel is thin.

Dental Enamel↗
PubMedDate not supplied

Reaction characteristics of a tooth-bleaching agent containing H2O2 and NaF: in vitro study of crystal structure change in treated hydroxyapatite and chemical states of incorporated fluorine.

This in vitro study was performed to elucidate the reaction mechanism of sodium fluoride (NaF), which is added to tooth-bleaching agents to lessen the adverse effect of hydrogen peroxide (H2O2) on teeth. Both hydroxyapatite (HAP) and dihydrated dicalcium phosphate (DCPD), model substances for dental hard tissues, dissolved easily in a simple H2O2 solution. In the H2O2/NaF solutions, however, fluorine compounds that could not be identified by X-ray diffraction (XRD) due to the smallness of the products were formed on the surface of the HAP. X-ray photoelectron spectroscopy (XPS) studies demonstrated that fluoridated hydroxyapatite (FHAP) was formed on HAP, and that calcium fluoride (CaF2) formation was accelerated by increasing the concentrations of fluorine and H2O2 along with the partial dissolution of HAP. In H2O2/NaF solution, DCPD also transformed easily to FHAP and CaF2, which are favorable to the remineralization process on the tooth surface. Thus, the mechanism of NaF was elucidated, and its use together with H2O2 for tooth bleaching was proved to be effective. Methodologically, the XPS two-dimensional plot made it possible for the first time to directly estimate the ratio of FHAP and CaF2 in the reaction products, in contrast to the conventional wet-analytical method, which is simply based on the difference in solubility of the two components.

Crystallization↗
PubMed2003

Effect of non-vital tooth bleaching on microleakage of coronal access restorations.

This study evaluated the effect of non-vital tooth bleaching on microleakage of composite resin/bovine tooth interface at different post-bleaching times. A total of 320 teeth were cleaned. A pulp chamber access cavity was made at the lingual surface of each tooth. The teeth were randomly divided into four groups: SPH - sodium perborate + 30% hydrogen peroxide; SPW - sodium perborate + distilled water; CP-37% carbamide peroxide; and CON-distilled water (control). The bleaching agents were replaced every 7 days, over 4 weeks. Following bleaching procedures, the groups were divided into four subgroups (n = 20), according to the post-bleaching times: 0 (baseline), 7, 14 and 21 days. After that, the cavities were restored with an adhesive system (Single Bond; 3M Co., St Paul, MN, USA) and a composite resin (Z100/3M). The specimens were thermocycled, stained with 2% methylene blue solution (pH 7), and sectioned longitudinally. The teeth were evaluated blind and independently by three previously calibrated examiners, to provide representative scores. The data were submitted to Kruskal-Wallis and multiple comparison tests (alpha=0.05). At baseline and 7 days, the SPH group showed a higher degree of dye penetration than the CON (P=0.04). At 14 and 21 days, there were no differences among groups. The association of sodium perborate with 30% hydrogen peroxide or with water may affect the sealing ability of composite resin restorations performed up to 7 days after bleaching procedures.

Adhesiveness↗
PubMed2006

Surface and pulp chamber temperature rises during tooth bleaching using a diode laser: a study in vitro.

OBJECTIVE: To measure the surface and pulp chamber temperature increases in vitro on upper and lower anterior teeth during a tooth whitening procedure using a diode laser. METHOD: A thermocouple was used to measure the temperature increase on the surface of an extracted upper central incisor tooth. Pulp chamber temperature readings were made on upper and lower central incisors, lateral incisors and canines. A diode laser recommended for tooth bleaching was tested at three different power settings (1W, 2W, 3W). Temperature measurements were made with and without the bleaching agent present on the labial tooth surface. RESULTS: The increase in surface temperature readings ranged from 37 degrees C (1W) to 86.3 degrees C (3W) with no bleaching gel present. Pulp chamber temperature increases ranged from 4.3 degrees C (1W) to 16 degrees C (3W). The presence of the bleaching gel reduced temperature increases seen at the tooth surface and within the pulp. CONCLUSIONS: The increase in the pulp chamber temperature with the laser used at 1-2W was below the critical temperature increase of 5.5 degrees C thought to produce irreversible pulpal damage. However, a power setting of 3W produced a pulp chamber temperature increase above this threshold (16 degrees C) and caution is advised when using this setting.

Body Temperature↗
PubMed1997

ADA supports vital tooth bleaching--but look for the seal.

The ADA has lent its support to tooth bleaching by providing procedural codes, educational materials and product evaluation procedures. The author describes the elements of the ADA product evaluation process and the role they should play in product development.

American Dental Association↗