Effect of violet LED light on in-office bleaching protocols: a randomized controlled clinical trial.

Objective This study evaluated the clinical effect of violet LED light on in-office bleaching used alone or combined with 37% carbamide peroxide (CP) or 35% hydrogen peroxide (HP). Methodology A total of 100 patients were divided into five groups (n=20): LED, LED/CP, CP, LED/HP and HP. Colorimetric evaluation was performed using a spectrophotometer (ΔE, ΔL, Δa, Δb) and a visual shade guide (ΔSGU). Calcium (Ca)/phosphorous (P) ratio was quantified in the enamel microbiopsies. Measurements were performed at baseline (T 0 ), after bleaching (T B ) and in the 14-day follow-up (T 14 ). At each bleaching session, a visual scale determined the absolute risk (AR) and intensity of tooth sensitivity (TS). Data were evaluated by one-way (ΔE, Δa, ΔL, Δb), two-way repeated measures ANOVA (Ca/P ratio), and Tukey post-hoc tests. ΔSGU and TS were evaluated by Kruskal-Wallis and Mann-Whitney, and AR by Chi-Squared tests (a=5%). Results LED produced the lowest ΔE (p<0.05), but LED/HP promoted greater ΔE, ΔSGU and Δb (T 14 ) than HP (p<0.05). No differences were observed in ΔE and ΔSGU for LED/CP and HP groups (p>0.05). ΔL and Δa were not influenced by LED activation. After bleaching, LED/CP exhibited greater Δb than CP (p>0.05), but no differences were found between these groups at T 14 (p>0.05). LED treatment promoted the lowest risk of TS (16%), while HP promoted the highest (94.4%) (p<0.05). No statistical differences of risk of TS were found for CP (44%), LED/CP (61%) and LED/HP (88%) groups (p>0.05). No differences were found in enamel Ca/P ratio among treatments, regardless of evaluation times. Conclusions Violet LED alone produced the lowest bleaching effect, but enhanced HP bleaching results. Patients treated with LED/CP reached the same efficacy of HP, with reduced risk and intensity of tooth sensitivity and none of the bleaching protocols adversely affected enamel mineral content.

Clinical Evaluation of In-Office Dental Bleaching Using a Violet Light-Emitted Diode.

Objective: To clinically evaluate the effect of the violet light-emitted diode (LED) light (405-410 nm) associated to in-office dental bleaching with 35% carbamide peroxide, on tooth color change and sensitivity. Participant's satisfaction after treatment was also evaluated. Materials and methods: A total of 50 participants were selected and randomized into a treatment group (n = 25): G1-two bleaching sessions of 30 min each, with 7-day interval (D0 and D7); G2-two bleaching sessions (same protocol as G1) associated with violet LED light, 30 min each session. The color evaluation was performed before and after 7 days of the second session (D0 and D14); the medium third of buccal surface of canine and central incisor teeth were evaluated under VITA Shade Guide and spectrophotometry (subjective and objective). Tooth sensitivity was evaluated immediately after the treatment and after 48 h of each bleaching session (D0, D2, D7, and D9), and a self-perception questionnaire was applied on D14. Results: Data were subjected to nonparametric Mann-Whitney test and both canine and central incisor teeth presented color change. Group G2 showed significantly more change than G1. Fisher's exact test showed no statistically significant dental sensitivity differences between groups. Both groups reported a high level of satisfaction but chi-square test showed statistically higher satisfied patients with dental bleaching in G2 than G1. Conclusions: The violet LED light (405-410 nm) could improve dental bleaching effectiveness, without sensitivity increase.

Conhecendo a terapia clareadora: efeito do local de aplicação e do volume de gel clareador na alteração cromática e sensibilidade pós-operatória: estudo clínico randomizado / Knowing the whitening therapy: effect of the application site and the volume of whitening gel on the chromatic alteration and postoperative sensitivity: randomized clinical trial

Embora o sucesso do clareamento dental tenha sido considerado dependente da dosagem utilizada, este procedimento ainda é cercado de importantes lacunas no que se refere à posologia utilizada e a forma de aplicação dos produtos clareadores. O objetivo deste estudo foi avaliar clinicamente o efeito do posicionamento do gel clareador e a influência de seu volume na alteração cromática e sensibilidade pósoperatória. Para o estudo referente ao posicionamento do gel clareador, trinta pacientes foram selecionados e alocados em três grupos (n=10): GI-aplicação na metade cervical, GII- aplicação na metade incisal, GIII- aplicação em toda a face vestibular. A quantidade e o tempo de aplicação do gel Peróxido de Hidrogênio a 35% foram padronizados. A análise de cor foi realizada pelo ΔE e WID (índice de clareamento), utilizando os valores obtidos pelas leituras realizadas em espectrofotômetro digital. As leituras foram realizadas nas regiões cervical e incisal dos dentes. A sensibilidade espontânea foi avaliada por questionário e a sensibilidade provocada através da análise termosensorial (TSA). As análises foram realizadas em 5 tempos: baseline, após 1º sessão clareadora (S), 2ºS e 3ºS e 14 dias após o término do clareamento. Os dados foram analisados pelo modelo de regressão linear com efeitos mistos e pós-teste por contrastes ortogonais (p< 0,05). Pode-se observar que, em relação à alteração cromática, apesar da região incisal ser momentaneamente favorecida pela aplicação do gel, ao final do tratamento, a restrição do local de aplicação à região cervical ou incisal proporcionaram resultados semelhantes aos obtidos quando o gel foi aplicado em toda a face vestibular. Quanto à sensibilidade, apenas o grupo que recebeu gel clareador na porção cervical apresentou sensibilidade espontânea. Já na análise termosensorial, o grupo que recebeu gel na face vestibular exerceu menor influência no limiar de sensação térmica. Paralelamente, no segundo estudo, em que se avaliou a influência do volume de gel clareador, os trinta pacientes foram alocados em três grupos: GI- 0,025mL, GII-0,05mL, GIII-0,10mL, e receberam o produto apenas nos caninos inferiores (n=10). A análise da alteração cromática foi realizada utilizando um espectrofotômetro digital portátil, sendo calculados os valores de ΔE, ΔL*, Δa*, Δb*, bem como o índice de clareamento (WID). A sensibilidade espontânea foi avaliada por aplicação de questionário e a sensibilidade provocada através da análise termosensorial. As análises foram realizadas em 5 tempos: baseline, após 1º, 2º e 3º sessões clareadoras e 14 dias após o término. Os dados foram analisados pelos testes Anova dois fatores com medidas repetidas e pós-teste de Tukey (p< 0,05). Observouse que o ΔE e o ΔL* foram semelhantes entre os grupos ao final da terapia clareadora. Os valores de Δa*, Δb*, bem com o WID foram mais intensos no grupo que recebeu 0,10mL, que também apresentou a maior sensibilidade espontânea e estimulada. Assim, através dos dois estudos realizados, pode-se concluir que ao final do tratamento, a alteração cromática independe do local de aplicação do gel clareador, entretanto, a região incisal, apresenta saturação cromática mais rápida que a região cervical. Constatou-se também que quanto maior o volume, maior a resposta clareadora nas coordenadas especificas e no índice de clareamento, entretanto, não apresentando diferença na alteração cromática e na luminosidade analisada. Já a sensibilidade dental foi mais intensa quando a aplicação do gel foi concentrada na região cervical, sendo também marcadamente proporcional ao volume empregado. Com isso, em relação ao grupo dental analisado, a redução do posicionamento do gel clareador para a incisal e a utilização de um volume intermediário (0,05mL), proporcionaram efeitos positivos para a alteração cromática e redução da resposta de sensibilidade(AU)

Although the success of tooth whitening was considered to be dependent on the dosage used, this procedure still has important gaps with regard to the dosage used and the form of application of the whitening products. The aim of this study was to evaluate clinically the effect of the positioning of the bleaching gel and the influence of its volume on the chromatic alteration and on the postoperative sensitivity. For the study of the positioning of the bleaching gel, thirty patients were selected and allocated into three groups (n = 10): GI- application on the cervical half, GII- application on the incisal half, GIII- application on the entire buccal surface. The amount and time of application of the 35% hydrogen peroxide gel were standardized. The color analysis was performed by ΔE and WID (lightening index), using the values obtained in the readings performed on a digital spectrophotometer. The readings were made in the cervical and incisal regions of the teeth. Spontaneous sensitivity was assessed using a questionnaire and the sensitivity caused by thermo-sensory analysis (TSA). The analyzes were carried out in 5 stages: baseline, after the 1st whitening session (S), 2ºS and 3ºS and 14 days after the end of the whitening. The data were analyzed using the linear regression model with mixed effects and post-test using orthogonal contrasts (p < 0.05). It can be seen that, regarding the chromatic alteration, although the incisal region is momentarily favored by the application of the gel, at the end of the treatment the restriction of the application site to the cervical or incisal region provided results similar to those obtained when the gel was applied throughout the vestibular face. As for sensitivity, only the group that received whitening gel in the cervical portion had spontaneous sensitivity. In the thermosensory analysis, the group that received gel on the vestibular face had less influence on the threshold of thermal sensation. In parallel, in the second study, in which the influence of the volume of the bleaching gel was evaluated, the thirty patients were allocated into three groups: GI-0.025mL, GII0.05mL, GIII-0.10mL, and received the product only in lower canines (n = 10). The chromatic alteration analysis was performed using a portable digital spectrophotometer, being calculated the values of ΔE, ΔL *, Δa *, Δb *, as well as the bleaching index (WID). Spontaneous sensitivity was assessed by applying a questionnaire and sensitivity by thermo-sensory analysis. The analyzes were carried out in 5 stages: baseline, after 1st, 2nd and 3rd whitening sessions and 14 days after the end. Data were analyzed using two-way ANOVA tests with repeated measures and Tukey's post-test (p < 0.05). It was observed that ΔE and ΔL * were similar between the groups at the end of the bleaching therapy. The values of Δa *, Δb *, as well as the WID were more intense in the group that received 0.10mL, which also showed the highest spontaneous and stimulated sensitivity. Thus, through the two studies carried out, it can be concluded that at the end of the treatment the chromatic alteration does not depend on the application site of the whitening gel, however, the incisal region, presents chromatic saturation faster than the cervical region. It was also found that the greater the volume, the greater the bleaching response in the specific coordinates and in the bleaching index, however, showing no difference in the chromatic alteration and in the analyzed luminosity. The tooth sensitivity was more intense when the application of the gel was concentrated in the cervical region, being also markedly proportional to the volume used. Thus, in relation to the analyzed dental group, the reduction of the positioning of the bleaching gel to the incisal and the use of an intermediate volume (0.05mL), provided positive effects for the chromatic alteration and reduction of the sensitivity response(AU)

Effect of violet LED light on in-office bleaching protocols: a randomized controlled clinical trial

Abstract Objective This study evaluated the clinical effect of violet LED light on in-office bleaching used alone or combined with 37% carbamide peroxide (CP) or 35% hydrogen peroxide (HP). Methodology A total of 100 patients were divided into five groups (n=20): LED, LED/CP, CP, LED/HP and HP. Colorimetric evaluation was performed using a spectrophotometer (ΔE, ΔL, Δa, Δb) and a visual shade guide (ΔSGU). Calcium (Ca)/phosphorous (P) ratio was quantified in the enamel microbiopsies. Measurements were performed at baseline (T 0 ), after bleaching (T B ) and in the 14-day follow-up (T 14 ). At each bleaching session, a visual scale determined the absolute risk (AR) and intensity of tooth sensitivity (TS). Data were evaluated by one-way (ΔE, Δa, ΔL, Δb), two-way repeated measures ANOVA (Ca/P ratio), and Tukey post-hoc tests. ΔSGU and TS were evaluated by Kruskal-Wallis and Mann-Whitney, and AR by Chi-Squared tests (a=5%). Results LED produced the lowest ΔE (p<0.05), but LED/HP promoted greater ΔE, ΔSGU and Δb (T 14 ) than HP (p<0.05). No differences were observed in ΔE and ΔSGU for LED/CP and HP groups (p>0.05). ΔL and Δa were not influenced by LED activation. After bleaching, LED/CP exhibited greater Δb than CP (p>0.05), but no differences were found between these groups at T 14 (p>0.05). LED treatment promoted the lowest risk of TS (16%), while HP promoted the highest (94.4%) (p<0.05). No statistical differences of risk of TS were found for CP (44%), LED/CP (61%) and LED/HP (88%) groups (p>0.05). No differences were found in enamel Ca/P ratio among treatments, regardless of evaluation times. Conclusions Violet LED alone produced the lowest bleaching effect, but enhanced HP bleaching results. Patients treated with LED/CP reached the same efficacy of HP, with reduced risk and intensity of tooth sensitivity and none of the bleaching protocols adversely affected enamel mineral content.

In-office tooth bleaching with 38% hydrogen peroxide promotes moderate/severe pulp inflammation and production of ll-1ß, TNF-ß, GPX, FGF-2 and osteocalcin in rats.

OBJECTIVES: To study the intensity of inflammatory infiltrate and production of interleukin-1ß (ll-1ß), tumor necrosis factor-ß (TNF-ß), fibroblast growth factor-2 (FGF-2), glutathione peroxidase (GPX), and osteocalcin in response to in-office tooth bleaching in rats. MATERIAL AND METHODS: Twenty male Wistar rats were randomized into four groups (n=5) according to the received treatment (tooth bleaching or no treatment - control) and the period of euthanasia after treatment (24 h or 10 days). We performed tooth bleaching using a 38% hydrogen peroxide gel on maxillary and mandibular incisors. After euthanasia, incisors (20 per group) were processed for histological analysis, immunohistochemistry staining of ll-1ß, TNF-ß, FGF-2 and GPX and osteocalcin by immunofluorescence. We analyzed data using the Mann-Whitney and Kruskal-Wallis/Dunn tests (p<0.05). RESULTS: The bleached groups presented statistically significant differences regarding the pulp inflammation stage compared with the control groups. Bleached teeth showed moderate/severe inflammatory infiltrate and control groups presented absent inflammatory cells or a negligible number of mononuclear cells (p<0.001) at two times (24 h and 10 days). There was strong staining for ll-1ß, TNF-ß, and GPX in bleached groups at 24 h and strong staining for ll-1ß, TNF-ß, GPX and FGF-2 at 10 days. After 10 days of tooth bleaching, the bleached group showed a statistically superior amount of osteocalcin than the other groups (p<0.01). CONCLUSIONS: Tooth bleaching with 38% hydrogen peroxide causes severe pulp inflammation, but characteristics of tissue repair after 10 days.

Evaluation of several clinical parameters after bleaching with hydrogen peroxide at different concentrations: A randomized clinical trial.

OBJECTIVE: This randomized double-blind clinical trial compared tooth sensitivity (TS), bleaching efficacy, and cytokine levels after applying in-office bleaching treatments containing 15% and 35% hydrogen peroxide (HP15% and HP35%, respectively). METHODS: Twenty-five volunteers were randomly assigned to receive HP15% or HP35% treatment. The bleaching agent was applied in three 15-min applications per session. Two bleaching sessions were separated by a 1-week interval. The participants scored TS using a visual analog scale and numerical rating scale. Bleaching efficacy was determined by subjective and objective methods. Gingival crevicular fluid was collected from three jaws sites per patient for the analysis of fluid volume. Flow cytometry was used to analyze gingival crevicular fluid levels of interleukin (IL)-1ß, IL-2, IL-4, IL-6, IL-10, tumor necrosis factor, and interferon-gamma. All measurements were obtained before and after bleaching. All data were statistically analyzed (α=0.05). RESULTS: The absolute risk and intensity of TS was higher for HP35% than for HP15% (p>0.002). One month post-bleaching, HP35% produced more bleaching than HP15% (p=0.02). However patient perception (p=0.06) and patient satisfaction (p=0.53) with regard to bleaching were not significantly different. No significant differences existed in the gingival fluid volume (p>0.38) or in any cytokine level (p>0.05) for either HP concentration. CONCLUSION: Treatment: with HP35% is more effective than HP15%, but generates a greater risk and intensity of TS. No inflammatory changes occurred despite the difference in the HP concentrations. CLINICAL SIGNIFICANCE: Hydrogen peroxide at a lower concentration (e.g., 15%) should be considered a good treatment alternative for in-office bleaching because the higher concentration for in-office bleaching generates a greater risk and intensity of TS for patients.

Effectiveness of LED/Laser Irradiation on In-Office Dental Bleaching after Three Years.

The present in vivo randomized, triple-blinded, and split-mouth clinical study evaluated the effectiveness of a hybrid light (HL) source on the color change, stability, and tooth sensitivity in patients submitted to different in-office bleaching techniques. Twenty volunteers were divided into two groups and four subgroups. A split-mouth design was conducted to compare two in-office bleaching techniques (with and without light activation): 35% Lase Peroxide Sensy (LPS) + HL: 35% hydrogen peroxide (HP) + HL; 35% LPS: 35% HP; 25% LPS + HL: 25% HP + HL; and 35% Whiteness HP (WHP): 35% HP. For the groups activated with HL, the HP was applied on the enamel surface three consecutive times using a 3 × 2-minute protocol (three HL activations for two minutes each, with a 30-second interval for a total of seven minutes and 30 seconds) for each gel application, totaling 22 minutes and 30 seconds. For the other groups, HP was applied 3 × 15 minutes, totaling 45 minutes. A spectrophotometer was used to measure the color change (ΔE) before the treatment and 24 hours, one week, and one, 12, and 36 months after. A visual analog scale was used to evaluate the tooth sensitivity before the treatment, immediately following treatment, 24 hours, and one week after. Analysis of variance, Tukey's, Kruskall-Wallis, and Wilcoxon tests, all with α = 0.05 were performed. Statistical analysis did not reveal any significant differences (ΔE) between the in-office bleaching techniques with or without HL in the periods evaluated; the activation with HL required 50% less time to achieve such results. The groups without HL presented statistical differences for ΔE when comparing 24 hours with the other follow-up times (intergroup) and an increase in tooth sensitivity in the initial periods. All techniques and bleaching agents were effective on bleaching during a 36-month evaluation of color stability. The groups activated with HL presented lower sensitivity and required a lower activation time.

High-concentration carbamide peroxide can reduce the sensitivity caused by in-office tooth bleaching: a single-blinded randomized controlled trial

Abstract Objectives A single-blinded, randomized, parallel clinical trial evaluated the use of 37% carbamide peroxide (CP) on bleaching effectiveness and tooth sensitivity reported by patients undergoing in-office tooth bleaching, in comparison with the results of using 35% hydrogen peroxide. Material and Methods Forty patients were allocated to receive two sessions of in-office tooth bleaching using either 35% hydrogen peroxide (HP) or 37% CP. Each patient's sensitivity level was evaluated during and up to 24 h after bleaching. The effectiveness of the bleaching procedures was evaluated with a spectrophotometer one week after each session and 30 days after the last session. The impact of tooth bleaching on the patients' perceptions regarding smile changes, in addition to the bleaching procedures and their results, were also recorded. Absolute and relative sensitivity risks were calculated. Data on sensitivity level were analyzed using the Mann-Whitney or T-test, and data from the color evaluation were subjected to 2-way repeated measures ANOVA. Results The use of CP reduced the risk and level of tooth sensitivity to values close to zero, whereas the difference between the bleaching agents disappeared after 24 h. An increased bleaching effect was observed for HP, mainly due to an improved reduction of redness and yellowness. Participants perceived improved tooth bleaching for HP and reduced sensitivity for CP, but no differences regarding the comfort of the techniques were noted. Conclusions In our study, 37% CP resulted in reduced tooth sensitivity but decreased the tooth bleaching effectiveness. However, both bleaching agents resulted in high levels of patient satisfaction.

In-office tooth bleaching with 38% hydrogen peroxide promotes moderate/severe pulp inflammation and production of ll-1ß, TNF-ß, GPX, FGF-2 and osteocalcin in rats

Abstract Objectives: To study the intensity of inflammatory infiltrate and production of interleukin-1β (ll-1β), tumor necrosis factor-β (TNF-β), fibroblast growth factor-2 (FGF-2), glutathione peroxidase (GPX), and osteocalcin in response to in-office tooth bleaching in rats. Material and Methods: Twenty male Wistar rats were randomized into four groups (n=5) according to the received treatment (tooth bleaching or no treatment - control) and the period of euthanasia after treatment (24 h or 10 days). We performed tooth bleaching using a 38% hydrogen peroxide gel on maxillary and mandibular incisors. After euthanasia, incisors (20 per group) were processed for histological analysis, immunohistochemistry staining of ll-1β, TNF-β, FGF-2 and GPX and osteocalcin by immunofluorescence. We analyzed data using the Mann-Whitney and Kruskal-Wallis/Dunn tests (p<0.05). Results: The bleached groups presented statistically significant differences regarding the pulp inflammation stage compared with the control groups. Bleached teeth showed moderate/severe inflammatory infiltrate and control groups presented absent inflammatory cells or a negligible number of mononuclear cells (p<0.001) at two times (24 h and 10 days). There was strong staining for ll-1β, TNF-β, and GPX in bleached groups at 24 h and strong staining for ll-1β, TNF-β, GPX and FGF-2 at 10 days. After 10 days of tooth bleaching, the bleached group showed a statistically superior amount of osteocalcin than the other groups (p<0.01). Conclusions: Tooth bleaching with 38% hydrogen peroxide causes severe pulp inflammation, but characteristics of tissue repair after 10 days.

Evaluation of an experimental rat model for comparative studies of bleaching agents

ABSTRACT Dental materials in general are tested in different animal models prior to the clinical use in humans, except for bleaching agents. Objectives To evaluate an experimental rat model for comparative studies of bleaching agents, by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats’ vital teeth. Material and Methods The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals were untreated (control). The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated through histomorphometric analysis with inflammatory cell count in the coronal and radicular thirds of the pulp. Fibroblasts were also counted. Scores were attributed to odontoblastic layer and vascular changes. Tertiary dentin area and pulp chamber central area were measured histomorphometrically. Data were compared by analysis of variance and Kruskal-Wallis test (p<0.05). Results After 2 days, the amount of inflammatory cells increased in the coronal pulp occlusal third up to the 15-min application groups of each bleaching gel. In the groups exposed to each concentration for 30 and 45 min, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, reduction on the pulp chamber central area and enlargement of the tertiary dentin area were observed, without the detection of inflammation areas. Conclusion The rat model of extracoronal bleaching showed to be adequate for studies of bleaching protocols, as it was possible to observe alterations in the pulp tissues and tooth structure caused by different concentrations and application periods of bleaching agents.

Evaluation of an experimental rat model for comparative studies of bleaching agents

ABSTRACT Dental materials, in general, are tested in different animal models prior to their clinical use in humans, except for bleaching agents. Objectives To evaluate an experimental rat model for comparative studies of bleaching agents by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats’ vital teeth. Material and methods The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals (control) were untreated. The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated by histomorphometric analysis with inflammatory cell counting in the coronal and radicular thirds of the pulp. The counting of fibroblasts was also performed. Scores were attributed to the odontoblastic layer and to vascular changes. The tertiary dentin area and the pulp chamber central area were histomorphometrically measured. Data were compared by the analysis of variance and the Kruskal-Wallis test (p<0.05). Results After 2 days, the amount of inflammatory cells increased in the occlusal third of the coronal pulp until the time of 15 min for both concentrations of bleaching gels. In 30 and 45 min groups of each concentration, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, a reduction in the pulp chamber central area and an enlargement of tertiary dentin area were observed without the detection of inflammation areas. Conclusion The rat model of extra coronal bleaching showed to be adequate for bleaching protocols studies, as it was possible to observe alterations in the pulp tissues and in the tooth structure caused by different concentrations and periods of application of bleaching agents.

Insight in the chemistry of laser-activated dental bleaching.

The use of optical radiation for the activation of bleaching products has not yet been completely elucidated. Laser light is suggested to enhance the oxidizing effect of hydrogen peroxide. Different methods of enhancing hydrogen peroxide based bleaching are possible. They can be classified into six groups: alkaline pH environment, thermal enhancement and photothermal effect, photooxidation effect and direct photobleaching, photolysis effect and photodissociation, Fenton reaction and photocatalysis, and photodynamic effect.

Evaluation of genotoxicity and efficacy of at-home bleaching in smokers: a single-blind controlled clinical trial.

OBJECTIVE: This single-blind controlled study evaluated the genotoxicity and efficacy of at-home bleaching in smokers and nonsmokers. METHODS: We selected 60 patients with central incisors A2 or darker: 30 smokers (experimental group) and 30 nonsmokers (control group). The bleaching was carried out with 10% carbamide peroxide for three hours a day for three weeks. The color was evaluated using a shade guide, Vita Bleachedguide 3D-Master, at baseline, during bleaching (first, second, and third weeks), and one week and one month after bleaching. Smears were obtained with a moistened wooden spatula from marginal gingiva. All the cytologic smears were stained with Giemsa solution. From each slide, 1000 cells were examined under 40× magnification and where micronuclei (MN) were located, they were examined under 100× magnification. The change in shade guide units at the different assessment periods and the frequency of MN were subjected to a two-way repeated measures analysis of variance and Tukey test (α=0.05). RESULTS: In both groups we detected a whitening of approximately 4 to 5 shade guide units, without color rebound after one month (p>0.05). The frequency of MN was significantly higher in the experimental group than in the control group, regardless of the bleaching treatment (p>0.001). CONCLUSION: The efficacy of bleaching does not appear to be affected by the smoking habit. Additionally, at-home bleaching did not induce DNA damage to the gingival tissue during the bleaching period.

Effectiveness of nano-calcium phosphate paste on sensitivity during and after bleaching: a randomized clinical trial

The study aimed to evaluate the effectiveness of in-office bleaching and associated tooth sensitivity on application of nano-calcium phosphate paste as desensitizing agent. Bleaching was performed with 35% hydrogen peroxide gel in 40 patients who were randomly divided into placebo and nano-calcium phosphate paste groups. Bleaching efficacy (BE) was evaluated using a value-oriented Vita shade guide. Tooth sensitivity was recorded using a numeric rating scale (0–4) during bleaching and up to 48 h after each session. The primary outcome of absolute risk of tooth sensitivity was compared using the Fisher’s exact test (α = 0.05). The intensity of tooth sensitivity and the efficacy of in-office bleaching were also statistically evaluated. No significant differences in absolute risk and intensity of tooth sensitivity were detected between the groups (p = 1.0 and p = 0.53, respectively). BE was also found to be similar between the groups (p = 0.67). Although the use of a nano-calcium phosphate paste associated with fluoride and potassium nitrate did not influence the whitening outcome, but it also did not reduce bleaching-induced tooth sensitivity.

Influência do perborato de sódio na desadaptação marginal de tampões cervicais confeccionados com diferentes materiais / Influence of sodium perborate on marginal misfit in cervical barrier made by different materials

Frente aos efeitos deletérios da reabsorção cervical externa, é de grande importância a confecção do tampão cervical quando do clareamento de dentes despolpados. Objetivo: este estudo avaliou a influência do perborato de sódio (PS) e o número de aplicações na desadaptação marginal do tampão cervical. Metodologia: Vinte e quatro pré-molares inferiores foram divididos em três grupos (n=8), de acordo com o material utilizado na confecção do tampão: Cimento de Ionômero de Vidro (CIV), Bioplic (BP) e Agregado de Trióxido Mineral branco (MTA B). Após a aplicação dos materiais, os espécimes foram aplainados e registrados por uma câmera fotográfica acoplada ao Esteromicroscópio. O PS diluído em soro fisiológico foi acomodado sobre os tampões e em seguida selados por 15 dias. Em seguida, o PS foi removido e novas imagens realizadas no Estereomicroscópio. Este ciclo foi repetido, determinando três períodos de avaliação. A desadaptação marginal foi calculada por meio do Software Image J, e os dados submetidos ao teste estatístico de Kruskal-wallis com post-hoc de Dunn para comparação intergrupos (α menor ou igual a 0,05), e teste de Friedman para comparação intragrupos (α menor ou igual a 0,05). Resultados: Verificou-se um aumento significativo na desadaptação marginal do BP e CIV entre os períodos controle e 2ª sessão. Na comparação intergrupos, o MTA B apresentou maior desadaptação quando comparado ao BP em todos os períodos. Conclusão: o PS foi capaz de aumentar a desadaptação marginal de dois materiais após 30 dias, e o MTA B seria o material menos indicado para confecção do tampão cervical...

Due to the deleterious effects of the external cervical resorption, it is extremely important the use of an appropriate cervical barrier in non-vital bleaching. Objective: this study evaluated the influence of sodium perborate (SP) and the number of its application on cervical barrier marginal misfit. Methods: twenty- four human premolars were divided into 3 groups (n=8) according to the material used in manufacture of barrier: Glass Ionomer cement (GIC), Bioplic (BP) and white Mineral Trioxide aggregate (W MTA). After the application of the materials, specimens were planed and registered with a camera mounted in a stereomicroscope. SP diluted in saline was accommodated on the barrier and then sealed for 15 days. Afterwards SP was removed and images were again obtained with stereomicroscope. This cycle was repeated once more, determine three periods of evaluation. Marginal misfit was obtained through Image J software, and the data was subjected to two-way analysis of variance, followed by Tukey post-hoc test (α or less 0,05). Results: there was a significant increase in the marginal misfit of BP and CIV between periods control and 2nd session. In the intergroup comparison, the MTA B showed larger marginal misfit when compared to BP in all periods. Conclusion: the PS was able to increase marginal misfit of 2 materials after 30 days, and the MTA B would be less suitable for making the cervical barrier...

High-efficiency tooth bleaching using non-thermal atmospheric pressure plasma with low concentration of hydrogen peroxide.

UNLABELLED: Light-activated tooth bleaching with a high hydrogen peroxide (HP; H2O2) concentration has risks and the actual role of the light source is doubtful. The use of conventional light might result in an increase in the temperature and cause thermal damage to the health of the tooth tissue. OBJECTIVE: This study investigated the efficacy of tooth bleaching using non-thermal atmospheric pressure plasma (NAPP) with 15% carbamide peroxide (CP; CH6N2O3) including 5.4% HP, as compared with conventional light sources. MATERIAL AND METHODS: Forty human teeth were randomly divided into four groups: Group I (CP+NAPP), Group II (CP+plasma arc lamp; PAC), Group III (CP+diode laser), and Group IV (CP alone). Color changes (∆E) of the tooth and tooth surface temperatures were measured. Data were evaluated by one-way analysis of variance (ANOVA) and post-hoc Tukey's tests. RESULTS: Group I showed the highest bleaching efficacy, with a ∆E value of 1.92-, 2.61 and 2.97-fold greater than those of Groups II, III and IV, respectively (P<0.05). The tooth surface temperature was maintained around 37°C in Group I, but it reached 43°C in Groups II and III. CONCLUSIONS: The NAPP has a greater capability for effective tooth bleaching than conventional light sources with a low concentration of HP without causing thermal damage. Tooth bleaching using NAPP can become a major technique for in-office bleaching in the near future.

High-efficiency tooth bleaching using non-thermal atmospheric pressure plasma with low concentration of hydrogen peroxide

Light-activated tooth bleaching with a high hydrogen peroxide (HP; H2O2) concentration has risks and the actual role of the light source is doubtful. The use of conventional light might result in an increase in the temperature and cause thermal damage to the health of the tooth tissue. Objective This study investigated the efficacy of tooth bleaching using non-thermal atmospheric pressure plasma (NAPP) with 15% carbamide peroxide (CP; CH6N2O3) including 5.4% HP, as compared with conventional light sources. Material and Methods Forty human teeth were randomly divided into four groups: Group I (CP+NAPP), Group II (CP+plasma arc lamp; PAC), Group III (CP+diode laser), and Group IV (CP alone). Color changes (∆E) of the tooth and tooth surface temperatures were measured. Data were evaluated by one-way analysis of variance (ANOVA) and post-hoc Tukey's tests. Results Group I showed the highest bleaching efficacy, with a ∆E value of 1.92-, 2.61 and 2.97-fold greater than those of Groups II, III and IV, respectively (P<0.05). The tooth surface temperature was maintained around 37°C in Group I, but it reached 43°C in Groups II and III. Conclusions The NAPP has a greater capability for effective tooth bleaching than conventional light sources with a low concentration of HP without causing thermal damage. Tooth bleaching using NAPP can become a major technique for in-office bleaching in the near future. .

A clinical study comparing the efficacy of light activated in-surgery whitening versus in-surgery whitening without light activation.

OBJECTIVES: This randomised controlled clinical trial assessed the efficacy of color change and sensitivity after in surgery whitening with and without light activation. METHODS: Twenty two patients were randomly assigned to one of two different groups: Group A--in-surgery bleaching with light activated 25% hydrogen peroxide gel followed by 2 weeks at home, night time bleaching with 10% carbamide peroxide gel in a customised bleaching tray. Group B--in-surgery bleaching with 25% hydrogen peroxide without light activation followed by 2 weeks at home, night time bleaching with 10% carbamide peroxide gel in a customised bleaching tray. The efficacy of tooth whitening was assessed by determining the color change associated with the six maxillary anterior teeth. Sensitivity was self-assessed with the use of a visual analogue scale (VAS). RESULTS: Overall, there was no significant difference in shade change between the two groups immediately after the in surgery whitening phase, and at one or two weeks post in surgery treatment. With regard to sensitivity immediately following the in surgery whitening participants in Group B reported a significantly higher level of sensitivity in comparison to Group A (p=0.03). CONCLUSIONS: There was no significant difference between the shade improvements achieved by the two whitening protocols tested throughout the 2-week period of the study (p>0.05). There was no statistical significant difference in sensitivity at the one and two week review periods, however, immediately after treatment participants in Group B reported a significantly higher level of sensitivity than participants in Group A (p=0.03).

Safety and efficacy of a high-adhesion whitening strip under extended wear regimen.

OBJECTIVES: This randomized, parallel group, single centre clinical trial was conducted to evaluate the safety and compare the whitening efficacy for an extended wear of an experimental 9.5% H2O2 high-adhesion whitening strip, relative to a marketed 10% H2O2 control strip. METHODS: Twenty-nine eligible adult volunteers were randomly assigned to either a treatment series with an experimental 9.5% H2O2 high-adhesion whitening strip at home for 2h, once a day, for 8 days; or a marketed 10% H2O2 whitening strip for 30 min, on a similar daily regimen. Tooth color/whitening progression was recorded under standardized lighting conditions at baseline, day 3, day 5, and day 9, via digital imaging. Outcomes were reported using the CIELAB system. Usage safety was also assessed at each follow-up visit. Whitening efficacy for each group was investigated using a paired-difference t-test. The treatment groups were compared among each other using the analysis of covariance, with the baseline value and age as the covariates. RESULTS: Both treatment groups demonstrated statistically significant mean color improvement from baseline for b* (yellow ness) and L* (lightness) at each post-baseline visit. In addition, the 2-h high-adhesion strips demonstrated significantly greater improvement in b* and L* relative to the 30-min strip group at each follow-up visit. CONCLUSIONS: The 2-h regimen for the 9.5% H2O2 high-adhesion whitening strip was more efficient for tooth whitening than the 30-min regimen of 10% H2O2 whitening strip. Both treatments were well tolerated and the use of the test products during the study time frame was considered safe. CLINICAL RELEVANCE: Extending the daily wear time of whitening strips can improve the efficacy of the treatment and ultimately shorten the length of the treatment without any significant adverse effects.

The effects of light on bleaching and tooth sensitivity during in-office vital bleaching: a systematic review and meta-analysis.

OBJECTIVE: To evaluate the influence of light on bleaching efficacy and tooth sensitivity during in-office vital bleaching. DATA SOURCES: We performed a literature search using Medline, EMBASE and Cochrane Central up to September 2011. STUDY SELECTION: All randomised controlled trials (RCTs) or quasi-RCTs comparing the light-activated bleaching system with non-activation bleaching system were included. Reports without clinical data concerning bleaching efficacy or tooth sensitivity were excluded. RESULTS: Eleven studies were included in the meta-analysis. A light-activated system produced better immediate bleaching effects than a non-light system when lower concentrations of hydrogen peroxide (15-20% HP) were used (mean difference [MD], -1.78; 95% confidence interval [CI]: [-2.30, -1.26]; P<0.00001). When high concentrations of HP (25-35%) were employed, there was no difference in the immediate bleaching effect (MD, -0.39; 95% CI: [-1.15, 0.37]; P=0.32) or short-term bleaching effect (MD, 0.25; 95% CI: [-0.47, 0.96]; P=0.50) between the light-activated system and the non-light system. However, the light-activated system produced a higher percentage of tooth sensitivity (odds ratio [OR], 3.53; 95% CI: [1.37, 9.10]; P=0.009) than the non-light system during in-office bleaching. CONCLUSIONS: Light increases the risk of tooth sensitivity during in-office bleaching, and light may not improve the bleaching effect when high concentrations of HP (25-35%) are employed. Therefore, dentists should use the light-activated system with great caution or avoid its use altogether. Further rigorous studies are, however, needed to explore the advantages of this light-activated system when lower concentrations of HP (15-20%) are used.