OBJECTIVETo investigate the influence of bleaching technique on vital tooth pulp.

METHODSA total of 40 vital teeth extracted for orthodontics were selected, of which, 10 teeth without any treatment served as control, 15 teeth were extracted instantly after bleaching and 15 teeth were extracted 7 days after bleaching. Slides were made from all these three groups and subject to pathological examination under microscope.

RESULTSNo clinical symptoms were found in all the teeth before and after bleaching. All teeth in the three groups showed normal pulp on pathological examination.

CONCLUSIONSBleaching did not affect vital tooth pulp and is a safe technique.

Dental Pulp ; pathology ; Humans ; Tooth Bleaching ; methods

When a tooth shows discoloration and does not respond to the cold test or electric pulp test (EPT) after a traumatic injury, its diagnosis can be even more difficult due to the lack of proper diagnostic methods to evaluate its vitality. In these case reports, we hope to demonstrate that ultrasound Doppler might be successfully used to evaluate the vitality of the tooth after trauma, and help reduce unnecessary endodontic treatments. In all three of the present cases, the teeth were discolored after traumatic injuries and showed negative responses to the cold test and EPT. However, they showed distinctive vital reactions in the ultrasound Doppler test during the whole observation period. In the first case, the tooth color returned to normal, and the tooth showed a positive response to the cold test and EPT at 10 wk after the injury. In the second case, the tooth color had returned to its normal shade at 10 wk after the traumatic injury but remained insensitive to the cold test and EPT. In the third case, the discoloration was successfully treated with vital tooth bleaching.
Diagnosis ; Hope ; Methods ; Tooth Bleaching ; Tooth Discoloration ; Tooth* ; Ultrasonography*

The study aimed to compare the whitening efficacy of a strip and gel containing 2.9% hydrogen peroxide, using a tooth whitening light activator. The whitening effect was compared through in vitro and in vivo studies. In the in vitro study, we used stained hydroxyapatite (HAP) specimens as artificial teeth. HAP specimens were made using HAP powder and polyvinyl alcohol solution, and stained by modified Stookey's method. A whitening gel and whitening strip were applied to the respective specimens for 20 minutes, with a light activator. The color changes were measured using a colorimeter. In the in vivo study, one group (test 1) used the gel with a light activator and the other group (test 2) used a strip with the same activator for 15 minutes a day, for four consecutive days. An organoleptic evaluation using a Vita shade guide and instrumental evaluation using a Shade eye-NCC (Shofu Co., Japan) were performed. The color change values (ΔE*) in the in vitro study revealed the strip with the light activator to be more effective than the gel with the same activator (p<0.001). In the in vivo study, even though there was no significant difference between the groups with respect to the ΔE*, using either the Shade eye-NCC or the Vita shade guide, the change in yellowness (Δb*) was statistically significant (p=0.024). In conclusion, test 2 group that used 2.9% hydrogen peroxide strip with a light activator, showed a tendency towards increased whitening than test 1 group that used the gel with the same activator; however further studies are needed to validate the above finding.
Durapatite ; Hydrogen Peroxide ; In Vitro Techniques ; Methods ; Polyvinyl Alcohol ; Sensation ; Tooth Bleaching* ; Tooth* ; Tooth, Artificial

OBJECTIVES: This study aimed to observe the color rebound and rebound rates of non-pulp discolored teeth within 1 year after routine internal bleaching to guide clinical practice and prompt prognosis. METHODS: In this work, the efficacy of bleaching was observed in 20 patients. The color of discolored teeth was measured by using a computerized colorimeter before bleaching; immediately after bleaching; and at the 1st, 3rd, 6th, 9th, and 12th months after bleaching. The L*, a*, and b* values of the color of cervical, mesial, and incisal parts of the teeth were obtained, and the color change amounts ΔE*, ΔL*, Δa*, and Δb* were calculated. The overall rebound rate (P*) and the color rebound velocity (V*) were also analyzed over time. RESULTS: In 20 patients following treatment, the average ΔE* of tooth color change was 14.99. After bleaching, the neck and middle of the teeth ΔE* and ΔL* decreased in the 1st, 3rd, 6th, 9th, and 12th months, and the differences were statistically significant. Meanwhile, from the 9th month after bleaching, the rebound speed was lower than that in the 1st month, and the difference was statistically significant. The incisal end of the tooth ΔE* and ΔL* decreased in the 6th, 9th, and 12th months after bleaching, and the differences were statistically significant. No significant difference was found in the rebound speed between time points. However, this rate settled after the 9th month, with an average color rebound rate of 30.11% in 20 patients. CONCLUSIONS The results indicated that internal bleaching could cause a noticeable color change on pulpless teeth. The color rebound after bleaching was mainly caused by lightness (L*), which gradually decreased with time, and it was slightly related to a* and b*. The color of the teeth after internal bleaching rebounded to a certain extent with time, but the color rebound speed became stable from the 9th month. Clinically, secondary internal bleaching can be considered at this time according to whether the colors of the affected tooth and the adjacent tooth are coordinated and depending on the patient's needs.
Humans ; Tooth Bleaching/methods* ; Tooth, Nonvital/drug therapy* ; Color ; Tooth Discoloration/drug therapy* ; Tooth ; Hydrogen Peroxide/therapeutic use* ; Tooth Bleaching Agents/therapeutic use*

OBJECTIVETo investigate the mechanism of discoloration and the efficacy of bleaching in non-infected traumatically discolored teeth.

METHODSIn vitro model of discolored teeth: sample of fresh erythrocytes was placed in the pulp cavity of 20 extracted teeth and centrifuged for 3 consecutive days. These discolored teeth were divided equally and randomly into two groups: group A (control group); group B (bleaching group), bleached with 10% carbamide peroxide gel for 4 weeks. And then all teeth were prepared for histological examination and subjected to a series of histochemical tests to analyze some of the biochemical changes following haemorrhage into the pulp chamber and post-bleaching.

RESULTSHaemoglobin and haematin were detected in the dentinal tubules of discolored teeth from group A and no evidence of ferric or haemosiderin. Specimens from group B demonstrated a negative response to histochemical tests.

CONCLUSIONSIn the absence of bacterial invasive, haemoglobin and haematin could cause discoloration of non-infected traumatized teeth. Peroxide bleaching agent can effectively remove haemoglobin and haematin.

Adolescent ; Child ; Humans ; In Vitro Techniques ; Random Allocation ; Tooth Bleaching ; methods ; Tooth Discoloration ; etiology ; therapy

OBJECTIVEThe purposes of this study were to investigate effects of chloroqquine (CQ) on inhibiting the decomposition of hydrogen peroxides (HP), and to optimize composition of the tooth-bleaching agent.

METHODSAccording to the principle of the color-changing reaction between horse radish peroxidase and substrate, the tooth-bleaching agent made of HP was divided into four groups with different amounts of CQ. The stability of HP was observed using ELISA for 3 months.

RESULTSWith the prolongation of store time, the absorbance of HP solutions containing different concentrations of CQ declined at different degrees, which showed a dependent relation between absorbance values and concentrations of CQ. Within the range of experiment concentrations of CQ, the higher the concentration of CQ was, the stronger the stability of HP was. And the duration of tooth-bleaching effects in 150.0 mg/ml of CQ was prolonged 4 to 6 times compared to that without CQ.

CONCLUSIONThe data indicate that CQ can inhibit the decomposition of HP. The bleaching effect of the tooth-bleaching agent which is made of HP and proper amount of CQ is satisfactory.

Chloroquine ; chemistry ; Drug Combinations ; Drug Interactions ; Humans ; Hydrogen Peroxide ; chemistry ; Tooth Bleaching ; methods

There has been increasing use of the H₂O₂-based teeth bleaching agents. The purpose of this study was to evaluate the bleaching effectiveness of the laser irradiation combined with nitrogen doped-TiO₂ nanoparticles (NPs) on the stained resin. Nitrogen (N) doped-TiO₂ NPs were prepared under sol-gel method. Light absorbance, X-ray diffraction patterns of NPs, and bleaching of methylene blue and stained resins were evaluated. For bleaching of stained resin, NPs-containing gel was used. For irradiation, light of two different wavelengths was used. Unlike TiO₂, N-TiO₂ showed high absorbance after 400 nm. N-TiO₂, which have used TiN as a precursor, showed a new rutile phase at the TiN structure. For methylene blue solution, N-TiO₂ with 3% H₂O₂ resulted in the greatest absorbance decrease after laser irradiation regardless of wavelength. For stained resin test, N-TiO₂ with 3% H₂O₂ resulted in the greatest color difference after laser irradiation, followed by group that used N-TiO₂ without 3% H₂O₂.
Methods ; Methylene Blue ; Nanoparticles ; Nitrogen ; Tin ; Tooth Bleaching Agents ; X-Ray Diffraction

OBJECTIVETo investigate a method of designing an accurate and scientific shade guide, especially used for judging the effect of tooth whitening, by analyzing the colorimetric values of discolored teeth statistically.

METHODSOne hundred thirty-six pictures of patients who had been receiving the Beyond cold light whitening treatment from February 2009 to July 2014 were analyzed, including 25 tetracycline teeth, 61 mottled-enamel teeth, and 50 yellow teeth. The colorimetric values of discolored teeth were measured. The L* values of shade tabs were calculated by hierarchical clustering of those of discolored teeth. The a* and b* values of shade tabs were the mean of those observed for discolored teeth. Accordingly, different shade guides were designed for each type of discolored teeth, and the effects were evaluated.

RESULTSA statistically significant difference in colorimetric values was found among the three types of discolored teeth. Compared with the Vitapan Classical shade guide, the shade guides designed through the present method were more scientific and accurate in judging the effect of tooth whitening. Moreover, the arrangement of shade tabs was more logical, and the color difference between shade tabs and discolored teeth was smaller.

CONCLUSIONThe proposed designing method is theoretically feasible, although its clinical effect has yet to be proven.

Color ; Colorimetry ; Dental Enamel ; Fluorosis, Dental ; Humans ; Incisor ; Light ; Prosthesis Coloring ; Research ; Tooth Bleaching ; methods ; standards ; Tooth Discoloration

OBJECTIVETo investigate the effect of 30% hydrogen peroxide(HP) with different pH values on color, translucency and laser-induced fluorescence of human dentin.

METHODSSixty dentin specimens from crown of mandibular third molars were randomly assigned into four groups (n = 15) and treated with acidic 30% HP, neutral 30% HP, alkaline 30% HP and deionized water (control group), respectively. The bleaching process was 0.5 h×4 times, and time points for measuring were baseline (0), 0.5, 1 and 2 h. A colorimeter was employed to measure the L(*), a(*), b(*) coordinates of dentin against white, black and yellow background. Then the parameters of translucency, masking effects, chroma and whiteness were calculated. The dentinal laser-induced Raman/fluorescence spectra was recorded by a Raman spectrometer and the fluorescence intensity(FI) and FI% were calculated.

RESULTSΔFI of acidic, neutral, alkaline 30% HP at 2 h were 9960.03 ± 2037.74, 8502.09 ± 1413.86, 8554.29 ± 1986.19. And ΔFI% were 84.60 ± 3.43, 84.89 ± 5.19, 86.72 ± 2.65, respectively. Repeated measure of ANOVA revealed that all parameters in the bleaching groups were significantly influenced by time (P < 0.001). Compared with control group, bleaching resulted significant change of ΔTP, Δchroma, Δwhiteness, ΔL(*), Δa(*), Δb(*), ΔE, ΔFI and ΔFI% (P < 0.001). There was no significant difference between three bleaching groups on ΔTP, Δmasking effects, Δchroma, Δwhiteness, ΔL(*), Δb(*), ΔE, ΔFI and ΔFI%. Correlation analysis demonstrated that FI was associated with chroma, a(*), b(*) and whiteness, respectively, and ΔFI was associated with ΔTP, Δmasking effects, Δwhiteness, Δchroma, Δb(*) and ΔE.

CONCLUSIONS30% HP with different pH values could result in the same change of the color, translucency and laser-induced fluorescence of human dentin.Laser-induced fluorescence was associated with dentinal color and translucency, which might be a novel way to investigate the bleaching mechanism of dentin.

Color ; Colorimetry ; methods ; Crowns ; Dentin ; anatomy & histology ; drug effects ; Fluorescence ; Humans ; Hydrogen Peroxide ; chemistry ; pharmacology ; Hydrogen-Ion Concentration ; Molar, Third ; Random Allocation ; Spectrum Analysis, Raman ; Tooth Bleaching ; methods ; Tooth Bleaching Agents ; chemistry ; pharmacology

OBJECTIVETo study the effects of the cold-light bleaching technique on crystals and microstructure of the dental enamel.

METHODSThe human premolars extracted for orthodontic reasons were treated by a standard cold-light bleaching procedure. After the treatment, all samples were detected by high resolution micro-area X-ray diffractometer, Fourier transform infrared spectroscope and scanning electron microscope.

RESULTSAfter the permanent teeth were treated with cold-light bleaching technique, the enamels' crystal dimension, crystallinity decreased and irregular surfaces and shallow disk pits appeared.

CONCLUSIONThe cold-light bleaching technique could lead to the changes of crystals and microstructure in the surface layer of dental enamel.

Bicuspid ; Dental Enamel ; radiation effects ; ultrastructure ; Humans ; Light ; Microscopy, Electron, Scanning ; Spectroscopy, Fourier Transform Infrared ; Tooth Bleaching ; methods