ABSTRACT
Magnetostrictive Co77Fe23 films are fully suspended to produce free-standing, clamped-clamped, microbeam resonators. A negative or positive shift in the resonant frequency is observed for magnetic fields applied parallel or perpendicular to the length of the beam, respectively, confirming the magnetoelastic nature of the shift. Notably, the resonance shifts linearly with higher-bias fields oriented perpendicular to the beam's length. Domain imaging elucidates the distinction in the reversal processes along the easy and hard axes. Together, these results suggest that through modification of the magnetic anisotropy, the frequency shift and angular dependence can be tuned, producing highly magnetic-field-sensitive resonators.
ABSTRACT
The present study investigated the effect of three high-viscosity bulk-fill resin-based composite materials on cuspal deflection in natural teeth. Thirty-two sound maxillary premolar teeth with large slot mesio-occlusal-distal cavities were distributed into four groups (n=8). Three groups were restored with bulk-fill resin composite materials (Tetric EvoCeram Bulk Fill, Ivoclar Vivadent, Schaan, Liechtenstein; x-tra fil, VOCO, Cuxhaven, Germany; and SonicFill, Kerr, Orange, CA, USA) in a single 4-mm increment. The conventional composite group, Filtek Z100 (3M ESPE, St Paul, MN, USA), was used to restore the cavities in 2-mm increments. Cusp deflection was recorded postirradiation using a Nikon measurescope UM-2 (Nikon, Tokyo, Japan) by measuring the changes in the bucco-palatal widths of the teeth at five minutes, 24 hours, and 48 hours after completion of the restorations. Cuspal deflection was significantly higher in the conventional composite than in the Tetric EvoCeram Bulk Fill ( p=0.0031), x-tra fil ( p=0.0029), and SonicFill Bulk ( p=0.0002) groups. There were no significant differences in cuspal deflection among the three bulk-fill materials (all p<0.05). In conclusion, all the investigated bulk-fill resin composites exhibited cuspal deflection values that were smaller than those associated with a conventional incrementally placed resin composite.
Subject(s)
Bicuspid/surgery , Composite Resins/therapeutic use , Dental Restoration, Permanent/adverse effects , Composite Resins/adverse effects , Dental Caries/surgery , Dental Restoration, Permanent/methods , Humans , Polymerization , Waxes/adverse effects , Waxes/therapeutic useABSTRACT
Exfoliation of two-dimensional phosphorene from bulk black phosphorous through chemical means is demonstrated where the solvent system of choice (choline chloride urea diluted with ethanol) has the ability to successfully exfoliate large-area multi-layer phosphorene sheets and further protect the flakes from ambient degradation. The intercalant solvent molecules, aided by low-powered sonication, diffuse between the layers of the bulk black phosphorus, allowing for the exfoliation of the multi-layer phosphorene through breaking of the interlayer van der Waals bonds. Through viscosity tuning, the optimal parameters (1:1 ratio between the intercalant and the diluting solvent) at which the exfoliation takes place is determined. Our exfoliation technique is shown to produce multi-layer phosphorene flakes with surface areas greater than 3 µm2 (a factor of three larger than what has previously been reported for a similar exfoliation method) while limiting exposure to the ambient environment, thereby protecting the flakes from degradation. Characterization techniques such as optical microscopy, Raman spectroscopy, ultraviolet-visible spectroscopy, and (scanning) transmission electron microscopy are used to investigate the quality, quantity, and thickness of the exfoliated flakes.
ABSTRACT
Patients are sometimes blamed for a reduced effect of bleaching when they do not adhere to a dentist's prescribed white diet. This study aimed to determine whether a white diet is necessary by evaluating the effects of coffee, tea, wine, and dark fruits on the potential tooth whitening during the bleaching process. Each of the effects of discoloration was categorized as "yes" or "no" based on a patient questionnaire. Data from five published studies were included in the analyses. Outcomes were based on the color change between baseline and the end of bleaching. The relationships between color changes were measured subjectively and objectively. A nonwhite diet was not significantly associated with less tooth whitening, and there was only a weak positive association between tooth whitening and diet for subjects who drank large amounts of coffee/tea.
Subject(s)
Diet/adverse effects , Tooth Bleaching/methods , Coffee/adverse effects , Fruit/adverse effects , Humans , Surveys and Questionnaires , Tea/adverse effects , Tooth Discoloration/etiology , Tooth Discoloration/prevention & control , Wine/adverse effectsABSTRACT
The purpose of this study was to determine if the actual concentration of bleaching agents available in four different countries were the same as the label indicated and within the recommendations of the International Standard on Tooth Whitening. The method recommended for assaying peroxide by the United States Pharmacopeia was used to determine concentrations. All products in the United States and China were within the standard when products were tested immediately upon delivery at testing sites. One product in Saudi Arabia and three products in Brazil had greater than 30% concentration loss. Three of 24 products in the United States did not meet the International Standard when they were tested at month of expiration.
Subject(s)
Drug Labeling/standards , Peroxides/analysis , Tooth Bleaching Agents/analysis , Brazil , Carbamide Peroxide , China , Drug Storage , Humans , Hydrogen Peroxide/administration & dosage , Hydrogen Peroxide/analysis , Hydrogen Peroxide/standards , Materials Testing , Peroxides/administration & dosage , Peroxides/standards , Pharmacopoeias as Topic , Reference Standards , Saudi Arabia , Time Factors , Tooth Bleaching Agents/administration & dosage , Tooth Bleaching Agents/standards , United States , Urea/administration & dosage , Urea/analogs & derivatives , Urea/analysis , Urea/standardsABSTRACT
UNLABELLED: Aged resin composites have a limited number of carbon-carbon double bonds to adhere to a new layer of resin. Study objectives were to 1) evaluate various surface treatments on repaired shear bond strength between aged and new resin composites and 2) to assess the influence of a silane coupling agent after surface treatments. METHODS: Eighty disk-shape resin composite specimens were fabricated and thermocycled 5000 times prior to surface treatment. Specimens were randomly assigned to one of the three surface treatment groups (n=20): 1) air abrasion with 50-µm aluminum oxide, 2) tribochemical silica coating (CoJet), or 3) Er,Cr:YSGG (erbium, chromium: yttrium-scandium-gallium-garnet) laser or to a no-treatment control group (n=20). Specimens were etched with 35% phosphoric acid, rinsed, and dried. Each group was divided into two subgroups (n=10): A) no silanization and B) with silanization. The adhesive agent was applied and new resin composite was bonded to each conditioned surface. Shear bond strength was evaluated and data analyzed using two-way analysis of variance (ANOVA). RESULTS: Air abrasion with 50-µm aluminum oxide showed significantly higher repair bond strength than the Er,Cr:YSGG laser and control groups. Air abrasion with 50-µm aluminum oxide was not significantly different from tribochemical silica coating. Tribochemical silica coating had significantly higher repair bond strength than Er,Cr:YSGG laser and the control. Er,Cr:YSGG laser and the control did not have significantly different repair bond strengths. Silanization had no influence on repair bond strength for any of the surface treatment methods. CONCLUSION: Air abrasion with 50-µm aluminum oxide and tribochemical silica followed by the application of bonding agent provided the highest repair shear bond strength values, suggesting that they might be adequate methods to improve the quality of repairs of resin composites.
Subject(s)
Composite Resins/chemistry , Dental Bonding , Dental Etching/methods , Lasers, Solid-State , Silanes/chemistry , Acid Etching, Dental/methods , Acrylic Resins/chemistry , Aluminum Oxide/chemistry , Dental Restoration Repair , Dental Stress Analysis/instrumentation , Humans , Materials Testing , Phosphoric Acids/chemistry , Resin Cements/chemistry , Shear Strength , Stress, Mechanical , Surface Properties , Temperature , Time FactorsABSTRACT
We demonstrate the first successful growth of large-area (200 × 200 µm(2)) bilayer, Bernal stacked, epitaxial graphene (EG) on atomically flat, 4H-SiC (0001) step-free mesas (SFMs) . The use of SFMs for the growth of graphene resulted in the complete elimination of surface step-bunching typically found after EG growth on conventional nominally on-axis SiC (0001) substrates. As a result heights of EG surface features are reduced by at least a factor of 50 from the heights found on conventional substrates. Evaluation of the EG across the SFM using the Raman 2D mode indicates Bernal stacking with low and uniform compressive lattice strain of only 0.05%. The uniformity of this strain is significantly improved, which is about 13-fold decrease of strain found for EG grown on conventional nominally on-axis substrates. The magnitude of the strain approaches values for stress-free exfoliated graphene flakes. Hall transport measurements on large area bilayer samples taken as a function of temperature from 4.3 to 300 K revealed an n-type carrier mobility that increased from 1170 to 1730 cm(2) V(-1) s(-1), and a corresponding sheet carrier density that decreased from 5.0 × 10(12) cm(-2) to 3.26 × 10(12) cm(-2). The transport is believed to occur predominantly through the top EG layer with the bottom layer screening the top layer from the substrate. These results demonstrate that EG synthesized on large area, perfectly flat on-axis mesa surfaces can be used to produce Bernal-stacked bilayer EG having excellent uniformity and reduced strain and provides the perfect opportunity for significant advancement of epitaxial graphene electronics technology.
ABSTRACT
This paper describes a technique of placing a semi-rigid cervical matrix slightly past the cervical border of a lesion that extends below (apical to) the gingival crest and inserting the glass ionomer cement through an opening cut in the matrix above the soft tissue level.
Subject(s)
Dental Restoration, Permanent/instrumentation , Tooth Abrasion/therapy , Tooth Cervix , Gingival Pocket/etiology , Glass Ionomer Cements , Humans , Matrix Bands , Tooth Abrasion/complicationsABSTRACT
This study determined the degradation of nine bleaching agents with different concentrations after two hours in vivo following the manufacturers' recommendations. The nine carbamide peroxide products are 10%, 15% and 20% Opalescence, 10%, 15% and 22% Rembrandt and 10%, 16% and 22% Nite White Excel 2. Each subject wore the tray with the bleaching agent for two hours on three separate occasions. The amount of remaining carbamide peroxide was determined after each use. Evaluation of remaining amount of carbamide peroxide was calculated by the US Pharmacopeia method. The study showed that the total carbamide peroxide percent recovered was significantly higher for Opalescence products (47% to 54%) compared to Nite White (22% to 25%) and Rembrandt bleaching gels (15% to 16%). It concluded that this difference was mostly due to the use of facial reservoirs with Opalescence products, and also that whitening gel in trays with reservoirs and trays without reservoirs degraded at the same rate.
Subject(s)
Peroxides/administration & dosage , Peroxides/chemistry , Tooth Bleaching , Urea/analogs & derivatives , Urea/administration & dosage , Urea/chemistry , Adult , Aged , Aged, 80 and over , Analysis of Variance , Carbamide Peroxide , Cross-Over Studies , Drug Combinations , Female , Humans , Kinetics , Male , Middle Aged , Statistics, Nonparametric , Tooth Bleaching/instrumentation , Tooth Bleaching/methodsABSTRACT
This in vivo study evaluated the variation of tray fabrication (trays constructed with or without reservoirs) on the degree of color change of teeth and sensitivities associated with using a 15% carbamide peroxide bleaching agent for two hours once daily for 14 days. Patients returned in one, two, three, six and 12 weeks. Color changes were evaluated by subjective shade matching, comparing clinical photographs and through measurements obtained using a color-measuring device. Subjects were asked to keep a daily record of any tooth and gingival sensitivity on the right and left side of their maxillary dental arch for three weeks. Colorimeter data showed that teeth lightened with agent with reservoirs were significantly lighter than teeth lightened with the same agent without reservoirs. However, the amount of lightening was below the threshold of visual differentiation. Shade guide and slide photography data showed no significant differences between teeth lightened with agent with reservoirs compared to teeth lightened with the same agent without reservoirs. In addition, no significant differences in tooth and gingival sensitivity were found between the tray side with reservoirs and those without reservoirs.
Subject(s)
Dental Devices, Home Care , Tooth Bleaching/instrumentation , Urea/analogs & derivatives , Adult , Aged , Analysis of Variance , Carbamide Peroxide , Colorimetry , Dentin Sensitivity/etiology , Double-Blind Method , Drug Combinations , Female , Humans , Male , Middle Aged , Peroxides/adverse effects , Statistics, Nonparametric , Surveys and Questionnaires , Tooth Bleaching/methods , Urea/adverse effectsABSTRACT
The use of flowable composites as liners in Class II packable composites has been suggested by some manufacturers. However, the contributions of this technique are unproven. This study evaluated marginal microleakage in Class II packable composite restorations with and without the use of a flowable composite liner. A conventional microhybrid composite was used as a control. Microleakage at occlusal and gingival margins of Class II cavities was evaluated using 45Ca and autoradiographs. Fifty non-carious, restoration-free human molar teeth were used. Separate mesio-occlusal and disto-occlusal Class II cavity preparations were made in each tooth. Gingival margins of all cavities were placed 1 mm apical to the cementoenamel junction (CEJ). Four Packable composites (Alert, Surefil, Pyramid and Solitaire) and one conventional microhybrid composite (Renew) with their respective manufacturer's bonding agents were used to restore the cavities. One side of each tooth was restored with composite alone, while the other side was restored with the composite lined with that manufacturer's flowable liner. The restored teeth were thermally stressed and 45Ca was used to evaluate microleakage. Two independent evaluators scored leakage based on the autoradiographs. The results showed flowable composites helped reduce microleakage at gingival margins of Class II restorations (p < 0.05). Gingival margins had higher microleakage than occlusal margins (p < 0.05). Without flowable liners, three packable composites (Alert, Pyramid and Surefil) showed higher leakage (p < 0.05) than the microhybrid control. Only Solitaire packable composite without liner showed no significant difference in microleakage to the control (p > 0.05). Although the flowable liners help reduce microleakage, Alert and Pyramid packable composites with liners still showed higher leakage than the control (p < 0.05). Surefil and Solitaire packable composites with flowable liners showed no significant difference in microleakage (p > 0.05) to the control.
Subject(s)
Composite Resins , Dental Cavity Lining , Dental Leakage/prevention & control , Analysis of Variance , Calcium Hydroxide , Dental Cavity Preparation , Dental Materials , Humans , Methacrylates , MolarABSTRACT
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.
Subject(s)
Dental Devices, Home Care , Hydrogen Peroxide/administration & dosage , Peroxides/administration & dosage , Tooth Bleaching/methods , Urea/analogs & derivatives , Adult , Carbamide Peroxide , Color/standards , Colorimetry , Dentin Sensitivity/chemically induced , Double-Blind Method , Drug Combinations , Gingival Diseases/chemically induced , Humans , Middle Aged , Tooth Bleaching/adverse effects , Urea/administration & dosageABSTRACT
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.
Subject(s)
Peroxides/administration & dosage , Tooth Bleaching/methods , Urea/analogs & derivatives , Urea/administration & dosage , Adult , Aged , Analysis of Variance , Carbamide Peroxide , Color , Colorimetry , Dental Enamel/drug effects , Dental Enamel/pathology , Dental Prophylaxis , Double-Blind Method , Drug Combinations , Female , Follow-Up Studies , Gingiva/drug effects , Humans , Male , Maxilla , Middle Aged , Nitrates/therapeutic use , Periodontal Index , Peroxides/adverse effects , Photography , Potassium Compounds/therapeutic use , Tooth Discoloration/drug therapy , Tooth Discoloration/therapy , Toothache/chemically induced , Toothache/prevention & control , Urea/adverse effectsABSTRACT
This article will address the breakdown or lowering of active bleaching agent concentration during use in the mouth. A greater than expected degradation occurs during the first 5 minutes followed by an exponential rate loss. Subjects have a large variation in degradation rates. After 2 and 6 hours there was 52% and 24% respectively, of the active agent present in a carbamide peroxide gel. The presence or absence of the pellicle did not affect the rate of degradation. The relationship of gel degradation to the whitening capability of a gel is yet to be determined.
Subject(s)
Oxidants/pharmacokinetics , Peroxides/pharmacokinetics , Tooth Bleaching/methods , Biodegradation, Environmental , Dental Deposits , Dental Devices, Home Care , Dental Pellicle , Dose-Response Relationship, Drug , Gels/pharmacokinetics , Humans , Hydrogen-Ion Concentration , Oxidants/administration & dosage , Oxidants/chemistry , Peroxides/administration & dosage , Peroxides/chemistry , Saliva/chemistry , Saliva/metabolism , Tooth Bleaching/instrumentationABSTRACT
BACKGROUND: The purpose of the study described here was to determine the in vivo degradation rate of 10 percent carbamide peroxide, or CP, gel in bleaching trays. The degradation rate indicates the remaining concentration of the active agent on the facial surfaces at various intervals. METHODS: The researchers fabricated bleaching trays with 0.5-millimeter reservoirs and loaded them with a 10 percent CP whitening gel. The tray was seated in place in 15 patients for six different intervals that ranged from 15 seconds to 10 hours. When the tray was removed, three samples were collected from each patient: the gel remaining in the tray; the adherent gel scraped from the teeth; and a "grab" sample from the reservoir of tooth no. 8. The researchers analyzed these samples for CP according to the method specified by the U.S. Pharmacopeial Convention. RESULTS: The percentage of CP recovered decreased as the intervals increased: 87 percent at 15 seconds, 10 percent at 10 hours. Log of tray, teeth and grab samples, respectively, at 15 seconds were 0.94, 0.98 and 0.96 and at 10 hours were -0.13, -0.38 and 0.11. The first-hour degradation rate for tray, teeth and grab samples, respectively, was 2.0 times, 3.6 times and one time the rate during the next nine hours. The within-subject repeatability of the samples was excellent. CONCLUSIONS: The degradation rate of CP during the bleaching process is biexponential. In the tray and teeth samples, the degradation rate was accelerated during the first hour. Further research is needed to determine the cause of this acceleration. CLINICAL IMPLICATIONS: The active agent in CP bleaching gel is available in bleaching trays for more than 10 hours. After two hours, more than 50 percent of the active agent is available, and 10 percent is available after 10 hours.
Subject(s)
Peroxides/chemistry , Tooth Bleaching/instrumentation , Urea/analogs & derivatives , Adult , Aged , Aged, 80 and over , Analysis of Variance , Carbamide Peroxide , Dental Devices, Home Care , Drug Combinations , Drug Stability , Female , Gels/chemistry , Humans , Male , Middle Aged , Regression Analysis , Reproducibility of Results , Statistics, Nonparametric , Time Factors , Urea/chemistryABSTRACT
The viewing of oral structures with an adequate level of illumination is necessary to make accurate diagnoses of normalities and abnormalities in the oral cavity. The purpose of this study is to determine if a device with an illuminated mirror is heat sterilizable, easy to use, and compares in illumination potential to a traditional overhead dental operating light. We sterilized the Denlite in both chemical vapor and autoclave units (including a group that was cleaned ultrasonically prior to autoclave), testing the illuminance level every 10 cycles, for 100 cycles. We installed devices in the Graduate Operative Dentistry Clinic and requested those operators assigned to the units to rate the devices. Their acceptance rate was high in visibility, ease of use, acceptable temperature of handle, and lack of problems with the device. The device had an illuminance level of 14,200 lux, which is just below the maximum level of illuminance required by the American Dental Association's Specification on Dental Operating Lights.
Subject(s)
Dental Instruments , Diagnosis, Oral/instrumentation , Lighting , Humans , Photometry , SterilizationABSTRACT
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.
Subject(s)
Peroxides/chemistry , Saliva/chemistry , Tooth Bleaching , Urea/analogs & derivatives , Analysis of Variance , Carbamide Peroxide , Dental Deposits/chemistry , Dental Pellicle , Drug Combinations , Humans , Time Factors , Urea/chemistryABSTRACT
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.
Subject(s)
Peroxides/therapeutic use , Tooth Bleaching/methods , Tooth Discoloration/therapy , Urea/analogs & derivatives , Adult , Analysis of Variance , Carbamide Peroxide , Chi-Square Distribution , Colorimetry , Cuspid/chemistry , Double-Blind Method , Drug Combinations , Female , Gels/therapeutic use , Humans , Incisor/chemistry , Longitudinal Studies , Male , Middle Aged , Periodontal Index , Urea/therapeutic useABSTRACT
Thirty patients whose teeth had been bleached were given one of two toothpastes. One half of the group brushed with a toothpaste containing 10% carbamide peroxide (DW) and the other half with a toothpaste containing 3% hydrogen peroxide (HP) for three months. Color change from baseline was evaluated after 4 weeks and again after 12 weeks, using a shade guide and measured with a colorimeter at baseline. The DW toothpaste was able to stabilize the tooth-lightening effect of the bleaching gel better than the HP toothpaste. The HP product had a lower tooth sensitivity rating.