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Introduction:Accumulated and compacted ear wax or cerumen can cause conductive hearing loss, discomfort and vertigo, and infection. This study investigates the effect of Carbamide peroxide (CP) compared with Phenol glycerin (PG) ear drops on cerumen.Materials and Methods:This experimental study investigated the effect of PG and CP ear drops on cerumen in ex vivo and in vivo phases. In the ex vivo phase cerumen degredation was scored following PG and CP treatments. In the in vivo phase, 29 patients with bilateral cerumen impaction were randomly entered the study. PG and CP were applied 3 times a day (each time 5 drops) for 4 days by patients. After treatments, the time of cerumen removal was measured.Results:Instant changes showing degredation of cerumen (grade 1) was evident when it was exposed to CP, on the other hand degredation changes (grade 1) in cerumen treated with PG was only evident after 20 min incubation at 37 oC, while grade 3 degredation was evident in cerumen treated with CP after the same time incubation. Although the time needed for removal of cerumen was lower in CP treatment (54.10±31.77) compared to PG treatment (67.10±35.54), the difference was not statistically significant.Conclusion:Based on the literature and our results, carbamide peroxide is suggested as a proper treatment for patients with EAC obstruction caused by cerumen compaction, because not only it is significantly effective in cerumen degredation, but also no side effects have been reported.

ABSTRACT Objectives This study assessed the effects of 15% and 20% carbamide peroxide (CP) on color, surface roughness, and hardness of computer‐aided design/computer‐aided manufacturing (CAD/CAM) dental ceramics. Materials and Methods This in vitro study was conducted on 120 Vita Mark II, Celtra Duo, and Suprinity CAD/CAM ceramic specimens. The ceramic specimens in each group (n = 40) were randomly assigned to two subgroups (n = 20) for polishing and glazing, and their baseline color, surface roughness (Ra), and hardness were assessed. In each subgroup, half of the specimens were exposed to 15% CP, while the other half were exposed to 20% CP. Their color change (ΔE), surface roughness, and hardness were then measured again. Surface roughness, hardness, and color were analyzed sequentially by profilometer, Vickers hardness tester, and spectrophotometer, respectively. Data were analyzed by repeated measures ANOVA, one‐way ANOVA, and post hoc Bonferroni test (α = 0.05). Results The surface roughness of all groups significantly increased after bleaching treatment (p

IntroductionTraditionally, internal tooth bleaching was performed using sodium perborate slurries. These are banned in some areas for potential carcinogenic effects. More recently, highly concentrated hydrogen peroxide gels have been used, which may cause dentin degradation. Consequently, the search for ideal internal tooth bleaching agents is still on. This study compared pure ROS-releasing granules regarding their liberation of oxidizing species, pH induction, bleaching of blood-stained dentin, and effects on mechanical dentin properties.Materials and methodsThe ROS-releasing granules under investigation were sodium perborate, carbamide peroxide, and sodium percarbonate in aqueous suspension (4:3, wt/wt). The bleaching efficacy of these suspensions was compared in blood-stained human dentin (n = 6) ex vivo. In addition, effects on mechanical dentin integrity were tested using bovine dentin beams (n = 9) exposed to a 3-point bending test (ISO 4049) after immersion in test suspensions or control solutions (35% H2O2 and physiological saline) for 1 week.ResultsGranules release between 21.5% and 35.2% (wt/wt) of H2O2 equivalent. The sodium-containing granules (perborate and percarbonate) caused an alkaline pH of 10.3 and 10.6, respectively. The carbamide peroxide suspension was acidic (pH 3.9), as was the 35% H2O2 solution used as a control (pH 2.2). All the suspensions bleached the blood-stained dentin, albeit with a lesser overall effect by sodium percarbonate (one-way ANOVA and Tukey's HSD, p

Objectives: This study aimed to compare changes in oral health-related quality of life (OHRQoL) resulting from three vital tooth bleaching protocols. Methods: The participants (n = 105) were randomly assigned to one of three vital bleaching treatment groups: home bleaching (HB), in-office bleaching (IOB), or combined bleaching (CB). HB involved the use of custom-made trays and 10% carbamide peroxide for a 14-day treatment period. IOB utilized 37.5% hydrogen peroxide applied in three cycles. CB treatment involved the use of IOB followed by HB. Tooth colour change was evaluated using a shade guide (ΔVS) and a digital spectrophotometry device (ΔES). The Oral Health Impact Profile-14 (OHIP-14) and Oral Impact on Daily Performance-22 (OIDP-22) instruments were used to assess changes in OHRQoL at baseline, 15-days and 6-month recalls. Linear mixed models were used to estimate between- and within-group differences. Results: All bleaching protocols led to significant improvements in overall OHIP-14 scores at the 6-month recall (p ≤ 0.037). CB and IOB treatments were associated with more substantial positive impacts on overall scores, psychological discomfort, physical disability (CB only), and psychological disability (CB only) compared to HB (p ≤ 0.011). Significant enhancements in OIDP-22 scores were observed in the CB and HB groups at the 6-month recall compared to baseline (p ≤ 0.006), with evidence indicating that these improvements were greater in the CB group compared to the IOB group (p = 0.007). Conclusion: All bleaching treatments demonstrated a positive impact on OHRQoL. However, the positive impact was most consistent across domains and age groups in the CB group. The positive impact was less pronounced in older age groups.

Abstract Objective This study assessed whether combining photobiomodulation therapy (PBMT) with casein phosphopeptide‐amorphous calcium phosphate fluoride (CPP‐ACPF) paste can effectively reduce post‐home whitening tooth sensitivity (TS) without compromising shade change. Methods Fifty participants were selected and assigned to one of four groups: (1) PLACEBO group—received a placebo paste and PBMT simulation; (2) PBMT group—received a placebo paste + PBMT; (3) CPP‐ACPF group—received CPP‐ACPF paste and PBMT simulation; (4) CPP‐ACPF + PBMT group—received both CPP‐ACPF paste and PBMT. The participants used whitening trays containing 22% carbamide peroxide for 2 h a day for 21 days. TS was measured daily using a visual analog scale, while shade change was assessed using a spectrophotometer: before bleaching treatment (T0), after the first (T1), second (T2), and third (T3) weeks of treatment, and 30 days (T4) after completing the whitening treatment. Results Intragroup analysis revealed that the PLACEBO group had the highest increase in sensitivity during the whitening treatment. The CPP‐ACPF and PBMT groups showed no significant difference tooth whitening (TW) between weeks regarding aesthetic change. The CPP‐ACPF and PBMT group exhibited a significant reduction in TS between the first and third and between the second and third weeks TW, but not between the first and second. Conversely, the PLACEBO group showed a higher sensitivity than the other groups (p .05). Conclusion Therefore, PBMT associated with CPP‐ACPF paste can reduce TS without compromising the efficacy of TW.

Abstract Objectives This study aimed to analyze the cost-effectiveness of whitening toothpastes and at-home bleaching for the treatment of tooth discoloration. Methodology A cost-effectiveness economic analysis was conducted, and eight randomized clinical trials were selected based on the whitening agent product used: blue covarine dentifrices (BCD), hydrogen peroxide dentifrices (HPD), dentifrices without bleaching agents (CD, negative control), and 10% carbamide peroxide (CP10, positive control) for at-home bleaching. The consumer/patient perspective was adopted, macro-costing techniques were used and a decision tree model was performed considering the costs in the American and Brazilian markets. The color change evaluation (ΔE*ab) was used to calculate the effectiveness of tooth bleaching. A probabilistic analysis was performed using a Monte Carlo simulation and incremental cost-effectiveness ratios were obtained. Results CP10 resulted in the highest cost-effectiveness compared to the use of dentifrices in both markets. In Brazil, HPD was more cost-effective than BCD and CD. In the US, the increased costs of HPD and BCD did not generate any whitening benefit compared to CD. Conclusions CP10 was more cost-effective than BCD and HPD for tooth bleaching from the perspectives of the Brazilian and American markets. Decision-making should consider the use of CP10 for treating tooth discoloration.

Objective To study the influence of procyanidins on the bonding strength of dentin bleached by carbamide peroxide to composite resin. Methods By applying different treatments to dentin bonding interfaces, 120 human third molars were randomly divided into 12 groups (n = 10): W group (no bleaching+deionized water), Wa group (no bleaching+deionized water+aging), WT1 group (no bleaching+5% procyanidins for 1 min), WT1a group (no bleaching+5% procyanidins for 1 min+aging), WT2 group (no bleaching+5% procyanidins for 5 min), WT2a group (no bleaching+5% procyanidins for 5 min+aging), C group (carbamide peroxide+deionized water), Ca group (carbamide peroxide+deionized water+aging), CT1 group (carbamide peroxide+5% procyanidins for 1 min), CT1a group (carbamide peroxide+5% procyanidins for 1 min+aging), CT2 group (carbamide peroxide+5% procyanidins for 5 min), and CT2a group (carbamide peroxide+5% procyanidins for 5 min+aging). The bond strength to composite resin was measured by universal mechanical testing machine, microstructure and the nanoleakages were measured by scanning electron microscope immediately or after the thermal cycling aging test. Results The immediate bond strength of the bleached groups pretreated with procyanidins for 1 min (P

Background: This study investigated the contact between adult dental pulp stem cells (DPSCs) and carbamide peroxide (CP), a bleaching agent that is a popular choice for at-home whitening products, using an in vitro model. Objectives: The aim of this study was to evaluate the impact of exposure to different concentrations and timings of a commonly used peroxide-based home tooth-whitening product on DPSCs. Materials and methods: Human DPSCs obtained from impacted third molars were cultured and exposed to various concentrations of carbamide peroxide (0.1%, 0.5%, and 1%). The effects of CP on DPSC proliferation and apoptosis were investigated by MTT assay and flow cytometry. Migration was investigated by micrographs of wound healing. An enzyme-linked immunosorbent assay (IL-6 and IL-8) was used to investigate the CP-stimulated cytokine production of DPSCs. Each experiment was performed three times with independent batches of DPSCs. Statistical analysis of the collected data was performed using one-way and two-way ANOVAs with the significance threshold set at p < 0.05. Tukey’s post hoc multiple comparison test was used to identify differences between groups. Results: Cell viability and adherence were lower in the CP-exposed cells compared to the non-stimulated cells, probably due to increased cell death (** p ≤ 0.01, **** p ≤ 0.0001). CP-stimulated DPSCs exhibited a dose-dependent release of IL-6 and IL-8 (**** p ≤ 0.0001). CP did not affect wound healing at any concentration tested. Conclusions: Human DPSCs were able to sense CP. Consequently, CP contributed significantly to cell apoptosis and local inflammatory responses through cytokine release.

Abstract The effectiveness of at-home dental bleaching treatments depends on the time that bleaching products are in contact with the teeth surface and, consequently, on the adequate use of associated custom acetate trays. Objective This randomized single-blinded trial aimed to analyze if the daily usage time of these products influences the patient’s compliance behavior when submitted to monitored at-home dental bleaching. Secondary outcomes were color change and tooth sensitivity. Methodology Sixty-six volunteers were randomly distributed into three groups (n=22): patients were instructed to use the trays for 2 (G2), 4 (G4), and 8 (G8) hours daily. The daily dental bleaching compliance behavior was measured using a microsensor inserted into the trays. Subjective and objective color evaluation assessments were adopted at baseline (T0), one (T1), two (T2), and three weeks (T3) after the beginning of the bleaching treatment, as well as two weeks after the treatment (T4). Tooth sensitivity was analyzed using the VAS scale, ranging from T1 to T4. Results G2 showed a greater degree of cooperation than G8 and cooperation was inversely proportional to the recommended usage time. Significantly higher color change was observed in the upper arch for G8 when compared to G2 in subjective analysis, from T1 to T4. There were no statistical differences between the groups in objective analysis. Conclusion Shorter recommended usage time of the bleaching product may improve the patient's compliance with at-home dental bleaching treatments. However, increased daily usage time may promote better subjective color change. Bleaching sensitivity was more significant in the first week for a longer time of use.

Background and Aim: Discoloration is an unfavorable side effect of regenerative endodontic procedures using mineral trioxide aggregate (MTA). The efficacy of home bleaching of discolored teeth with carbamide peroxide has not been well investigated, and the minimum required duration of home bleaching is still unclear. This study aimed to compare the effects of different durations of home bleaching on tooth discoloration caused by MTA. Materials and Methods: This in vitro, experimental study used 16 tooth blocks of bovine central incisors. To cause discoloration, white MTA was applied for 40 days in cavities drilled in blocks. The color parameters were measured at baseline and at 14, 28, and 42 days after the application of 20% carbamide peroxide using a spectrophotometer. Data were analyzed by repeated measures ANOVA and Tukey’s post-hoc test. Results: The color change (∆E) value was 22.9±10, 26.3±10.9, and 27.03±11 at 14, 28, and 42 days after bleaching, respectively. Significant color change occurred at 2, 4, and 6 weeks after the application of carbamide peroxide (P

Abstract Background The aim of this study was to evaluate the effect of bioactive glass (BAG) 45S5 paste on colour change and tooth sensitivity (TS) when used in combination with 20% carbamide peroxide (CP) during at-home vital tooth bleaching. Methods Twenty-four patients were selected and assigned into two experimental groups (n = 12) in a double-blind study design. Each patient received 20% CP followed by the application of either BAG paste or non-active placebo paste. The shade evaluation was performed using a digital spectrophotometer based on the CIE L*a*b* colour space system at different time points and the overall colour changes ΔE were calculated. TS was evaluated using visual analogue scale (VAS). The values of ΔE and TS were statistically analysed using paired t-test. The level of statistical significance was established at p = 0.05. Results The overall colour changes (ΔE) between baseline and each time point showed no significant differences between BAG and placebo groups (p > 0.05). The use of BAG paste significantly decreased TS reported by the participants. Conclusions The association of BAG paste with at-home bleaching treatment presents a promising method as it decreased TS and did not deteriorate bleaching efficacy. Trial registration This study was approved and registered in the Australian New Zealand Clinical Trials Registry (ANZCTR) under Registration number: ACTRN12621001334897.

Aim: The present in vitro study was designed to determine the effect of different access cavity designs on intracoronal bleaching of endodontically treated teeth with two different agents. Materials and Methods: Fifty selected permanent maxillary central incisors were stained. Traditional and contracted access cavity designs and two types of bleaching agents, i.e., 35% carbamide peroxide and 35 percent hydrogen peroxide were used for the study. Color measurements were performed with a spectrophotometer: before staining (T1), after staining (T2), at 7 and 14 days (T3 and T4) post bleaching. The values were calculated and subjected to the statistical analysis. Results: The results of our study showed that teeth in which traditional access cavity (TAC) was prepared had statistically significant better bleaching results with both 35% carbamide peroxide and 35% hydrogen peroxide than contracted access cavity design. Carbamide peroxide showed better results than hydrogen peroxide irrespective of the access cavity design, but difference was statistically nonsignificant. Conclusion: The present study concluded that TAC design showed better results than contracted access with both carbamide peroxide and hydrogen peroxide. Whereas, when bleaching agents were compared 35% carbamide peroxide is better than 35% hydrogen peroxide irrespective of access cavity design used.

Changes in tooth form, texture and shade inevitably accompany the aging of the people. The desire of improving smile appearance leads to an increase in the request of esthetic dental procedures. Bleaching is now the most common and non-invasive esthetic dental treatment. Even if it is considered a cosmetic dental treatment, the dentist always should establish a diagnosis and treatment plan before initiate the procedure. This study aims to evaluate the Romanian dentists approach to vital and non-vital bleaching procedures and to assess if there are correlations between their options and the time of clinical practice or the postgraduate training. The cross-sectional study was undertaken using a closed questionnaire addressed to dentists by online method. The twenty questions focused on the following topics: time of clinical practice, self-perception on safety of the treatment, self-confidence in providing bleaching, postgraduate training, the main technique for vital and non-vital tooth bleaching therapies, first choice material, the use of light activation, the need for desensitizing agents and the attitude towards restorations.

Background: Dental aesthetic procedures aim to rectify flaws in dental elements’ shape, alignment, or overly dark color. One of the most common dental aesthetic procedures is tooth whitening. This study attempts to introduce key aspects of bleaching and describe the different techniques and the mechanism of action of bleaching agents, focusing on the clinical implications in orthodontic and on composite restorations. Methods: The research was performed on PubMed, Web of Science, and Science Direct databases for articles on our topic published between 2017 and 2023, and we found a total of 1512 studies. In total, 57 papers were considered for the qualitative analysis in the review. Results: This study found that both carbamide peroxide and hydrogen peroxide were clinically effective, although patients’ level of tooth sensitivity seemed to be lessened by the latter. However, the latter appears to be more effective at reducing patient-experienced tooth sensitivity. Conclusion: Carbamide and hydrogen peroxide based whitening techniques were shown to be equally successful at treating tooth discoloration after bracket composite removal, with no discernible differences between them. To increase the effectiveness of whitening on composites, more research is needed. To achieve the desired results and avoid the negative effects of whitening gels on teeth and soft tissue, a patient-specific approach is advised.

Background and Objective: Tooth bleaching changes the microhardness and mineral content and color of the tooth. The present study aimed to evaluate the effect of carbamide peroxide on microhardness, mineral content and color change in white spot lesions. Material and Methods: Thirty-two samples were selected without caries, cracks and stains, and immersed in 0.5% chloramine-T for one week. Then the tooth crowns were separated. The teeth were artificially decayed by pH cycling. For bleaching on the enamel, a coating of 10% carbamide peroxide gel with a thickness of 1 mm was used for 8 hours. Samples were stored in artificial saliva for 16 hours. Bleaching process lasted for 14 days. Microhardness, color changes, calcium and phosphorus levels were measured before and after bleaching. Paired t-test and one-sample test were used to analyze the data. Results: The microhardness test results were 338.02± 90.15 and 320.94±87.41 before and after bleaching, respectively. microhardness of the samples significantly decreased after bleaching compared to before bleaching (P0.05). The mean color change coefficient (∆E) after bleaching was 6.82±3.96. ∆E in the studied samples was significantly higher than the standard (∆E =3.3). Conclusion: Bleaching with 10% carbamide peroxide significantly reduced microhardness. There was no change in the mineral content of the enamel and color change was proper. It can be concluded from this study that bleaching with carbamide peroxide can be successful.

Aim: The aim of this study was to evaluate and compare the effect of 10% sodium ascorbate and propolis solution on the microtensile bond strength (MTBS) and resin tag penetration depth of composite after using 35% carbamide peroxide bleaching agent. Materials and Method: Sixty extracted human premolars were divided into five groups with 12 samples in each. Group I samples did not receive bleaching treatment and served as control. Group II samples were bonded with composite 2 weeks later, while those in Group III were bonded immediately after bleaching. The samples in Group IV and Group V were treated with antioxidants 10% SA and propolis solution at the rate of 1ml/min for 10 min, respectively, before composite bonding. The samples were then sectioned mesiodistally into two halves. One half was subjected to MTBS testing using a Universal Testing Machine. The other half was decalcified, sectioned, stained, and viewed under an optical light microscope to assess the resin tag penetration. The results obtained were statistically analyzed using a one-way analysis of variance followed by Post hoc test. Results: Group III showed significantly lower MTBS and resin tag penetration depth of composite compared to all other groups. Group V (propolis group) showed statistical significance with all groups except Group IV (SA group). Conclusion: Treatment with antioxidant propolis solution immediately following the bleaching will help to reverse the compromised bond strength which is comparable with sodium ascorbate.

Background: Home bleaching with carbamide peroxide is commonly used due to its high success rate and minimum side effects. Although home bleaching is safe, it causes structural changes in surface enamel, thereby facilitating Streptococcus mutans attachment on the enamel surface. Objectives: This study aimed to determine the effect of carbamide peroxide concentration on surface enamel structural changes and S. mutans attachment. Methods: Healthy, caries-free, and calculus-free upper first premolars were divided into 10%, 15%, and 35% carbamide peroxide concentration groups, with five samples in each group. Structural changes in the surface enamel of the teeth before and after the bleaching procedure were assessed subjectively based on observations using a stereomicroscope at × 40. The samples were inoculated in S. mutans culture and incubated for 24 h (37°C) in anaerobic conditions. The samples were then washed with phosphate-buffered saline, and bacterial attachment was released by vortexing for 1 min. Bacterial attachment was assessed using a turbidimetry test and total plate count test. Result: Structural changes in enamel were observed in the samples exposed to carbamide peroxide 35%. The results of an analysis of variance test revealed a significant difference (P < 0.05) in the bacterial attachment test. The samples exposed to carbamide peroxide 35% exhibited the highest amount of bacterial attachment (3 × 10[6] CFU/mL, optical density: 0.06). Conclusion: The concentration of carbamide peroxide plays a role in structural changes in enamel and S. mutans attachment.

Objective. The causes of internal posteruptive discoloration of teeth are bleeding, necroses, infections, and endodontic filling materials. The aim of this study was to establish the results of bleaching endodontically treated teeth using walking bleach, in-office, and combined techniques, using 30% carbamide peroxide and 35% hydrogen peroxide, as well as the effect of etiological factors, and the time elapsed after endodontic treatment on the success of bleaching. Materials and Methods. The research involved 30 endodontically treated teeth in healthy patients. Retroalveolar X-rays were taken to check the quality of root canal obturation. Endodontic treatment and obturation were carried out on the discolored non-vital teeth without any previous endodontic treatment. Before bleaching, two millimeters of the filling were removed from the root canal and the very entry into the canal was protected with glass ionomer cement. The teeth were divided into three groups, depending on the bleaching technique: walking bleach technique (10 patients), in-office technique (10 patients), and combined technique (10 patients). The teeth were bleached with 30% carbamide peroxide and 35% hydrogen peroxide. The bleaching procedure was repeated in all the patients three times. The color of all teeth was determined based on the Vita Classic guide before and after bleaching. The Χ2 square and Kruskal–Wallis tests were used to identify differences in teeth bleaching results. Results. A statistically significant difference (p < 0.05) was established between bleaching success and the time elapsed after endodontic treatment. There were no statistically significant differences observed between the bleaching success and etiological factors, bleaching techniques, or bleaching agents. Conclusions. The effectiveness of non-vital tooth bleaching is affected by the time elapsed after endodontic treatment.

Background: Activated charcoal is a nanocrystalline form of carbon with a large specific surface area and high porosity in the nanometer range, having consequently the capacity to absorb pigments, chromophores, and stains responsible for tooth color change, while carbamide peroxide is unstable and breaks down immediately upon contact with tissue and saliva, first dissociating into hydrogen peroxide and urea and subsequently into oxygen, water, and carbon dioxide. Therefore, the aim of the present study was to assess the effect of 16% carbamide peroxide and activated-charcoal-based whitening toothpaste on enamel surface roughness in bovine teeth. Materials and Methods: The present experimental in vitro, longitudinal, and prospective study consisted of 60 teeth randomly distributed in six groups: A: artificial saliva, B: conventional toothpaste (Colgate Maximum Protection), C: whitening toothpaste with activated charcoal (Oral-B 3D White Mineral Clear), D: 16% carbamide peroxide (Whiteness Perfect 16%), E: 16% carbamide peroxide plus conventional toothpaste (Whiteness Perfect 16% plus Colgate Maximum Protection), and F: 16% carbamide peroxide plus whitening toothpaste with activated charcoal (Whiteness Perfect 16% plus Oral-B 3D White Mineral Clear). Surface roughness was assessed with a digital roughness meter before and after each treatment. For the statistical analysis, Student’s t test for related samples was used, in addition to the ANOVA test for one intergroup factor, considering a significance level of p < 0.05. Results: The surface roughness variation of bovine tooth enamel, before and after application of bleaching agent, was higher in groups of whitening toothpaste with activated charcoal (0.200 µm, Confidence Interval (CI): 0.105; 0.296 µm) and 16% carbamide peroxide plus whitening toothpaste with activated charcoal (0.201 µm, (CI): 0.092; 0.309 µm). In addition, bovine teeth treated with conventional toothpaste (p = 0.041), whitening toothpaste with activated charcoal (p = 0.001), and 16% carbamide peroxide plus whitening toothpaste with activated charcoal (p = 0.002) significantly increased their surface roughness values. On the other hand, significant differences were observed when comparing the variation in surface roughness between the application of artificial saliva (control) and the whitening toothpaste with activated charcoal (p = 0.031), and the 16% carbamide peroxide plus whitening toothpaste with activated charcoal (p = 0.030). Conclusion: The use of whitening toothpaste with activated charcoal and in combination with 16% carbamide peroxide significantly increased enamel surface roughness in bovine teeth.

ABSTRACT Tooth bleaching is one of the most conservative aesthetic techniques. At-home and in-office bleaching may be performed, as well as the combination of both techniques. As this combination may be done in different manners, distinct orders of combinations were proposed in this report. A 24 years-old man, whose upper central incisor and canine shades were A2 and A3 respectively, was initially treated by chair-side with 40-min application of 40% hydrogen peroxide (HP) for two sessions. Afterwards, an two-week overnight at-home bleaching was performed with 10% carbamide peroxide (CP). The shade of upper central incisors changed to 1M1 and canine was B1. Conversely, a 30 years-old woman was firstly conducted with at-home bleaching (overnight 4-weeks 10% CP) and, subsequently, with a single appointment of in-office bleaching for 45 minutes (35% HP). The shade of her upper central incisor changed from A1 to 0.5M1 and the upper canine from A3 to B1. The VITA classical (A1-D4) shade guide and VITA Bleached guide 3D-MASTER were used to determine the tooth color during the treatments. In both bleaching treatments, patients reported no significant tooth sensitivity and the final outcomes met their expectation.

Abstract Objective Our study aims to compare the efficacy and tooth sensitivity following in-office (35% hydrogen peroxide) or at-home (10% carbamide peroxide) bleaching treatments both preceded by 2% potassium nitrate (2%KF) desensitizing gel. Methodology 130 volunteers were randomly allocated to a) in-office bleaching and a placebo at-home protocol; or b) in-office placebo and at-home bleaching treatment. 2% KF was applied for 10 min before both treatments. Objective color evaluation was performed (spectrophotometer CIEL*a*b* system and CIEDE2000) to calculate the color change (ΔE00). Subjective evaluation was performed using the VITA classical shade guide followed by shade variation (ΔSGU) at the beginning and end of bleaching treatment and 2 weeks post-bleaching. Tooth sensitivity was daily recorded using a Likert scale varying from 1 (no sensitivity) to 5 (severe sensitivity). Analysis was carried out using non-parametric tests. Results Regarding the color change, at-home bleaching resulted in significant color improvement compared to in-office treatment for the parameters Δb* (p=0.003) and Δa* (p=0.014). Two weeks post-bleaching, the at-home treatment resulted in significant color improvement compared to in-office treatment for the parameters Δb* (p=0.037) and ΔE00 (p=0.033). No differences were observed in either ΔSGU parameters. Concerning sensitivity, patients treated with in-office bleaching reported more tooth sensitivity than the at-home group only on the first day after bleaching started, without significant differences in the other periods evaluated (p>0.05). Conclusions At-home and in-office bleaching, preceded by a desensitizing agent, were effective for vital teeth bleaching and 10% carbamide peroxide produced a higher whitening effect than 35% hydrogen peroxide in the short time evaluation. Tooth sensitivity rates were similar for the two techniques tested.

The objective of this article was to systematically review the literature to determine how effective tooth whitening procedures are when carried out in tandem with orthodontic clear aligners. This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Online searches of PubMed, Medline via Ovid, Science Direct, the Cochrane database of systematic reviews via Ovid, Scopus, and Google Scholar as well as manual searches of the references of the selected articles were conducted. Clinical studies which assessed the efficacy of dental bleaching using orthodontic clear aligners were included in the present study. Data from the included studies were extracted and assessed for risk of bias using the Cochrane risk of bias tool. Three studies met the inclusion and exclusion criteria and were included in this study. One study compared the efficiency of tooth bleaching between clear aligners and conventional bleaching trays. One study evaluated the effectiveness of dental bleaching using clear aligners by comparing the tooth shade of those patients to a control group of patients who did not receive dental bleaching during orthodontic clear aligner treatment. One study evaluated the effectiveness of different concentrations of different bleaching agents using clear aligners. All the included studies showed an improved tooth shade when using clear aligners as bleaching trays.

Introduction: The success of intracavity bleaching in nonvital teeth is related to the ability of penetration or diffusion of the bleaching agent into dentin and enamel tissues. This manipulation can be done with some active ingredients as carbamide peroxide, hydrogen peroxide or sodium perborate. Some of the most popular techniques that can be used for this purpose are inside/outside bleaching technique, in-office bleaching, the walking bleaching technique, thermocatalytic technique. Тhe carbamide peroxide gel is used in different concentrations. Recently this whitening agent is more recommended for use in intracoronal bleaching. Purpose: The aim of this case report is to show the quick effect of intracavity bleaching of the discolorated crown of nonvital central incisor, using a 45% carbamide peroxide gel. Material and methods: A modified walking bleaching method is presented in bleaching of a single discolored nonvital central incisor (11). Results: The color of the tooth was changed to the aesthetic demands of the patient after 3 intracavity applications of bleaching agent. Conclusion: Carbamide peroxide gel is a secure option for fast and satisfying intracavity bleaching.

Background: Varieties of methods are available for more obstinate tooth discoloration such as crowns, veneer, and micro and macro abrasion of enamel, but tooth bleaching gained high patient acceptance. The aim of the present research was to estimate changes in surface enamel composition after bleaching 16% carbamide peroxide (CP) (home-use bleaching) with 38% hydrogen peroxide (HP) (in office bleaching). Materials and Methods: A total of 90 enamel slabs from 45 sound human third molars were randomly divided into three groups. Of three groups, per group had thirty samples (n = 30), of which samples of Group 1 were placed in artificial saliva at 37°C in incubator (Memart, Germany) during complete experiment. Sample of Groups 2 and 3 was treated with power whitening gel (White Smile 2011, Germany) and tooth whitening pen (white Smile 2011, Germany), respectively. Later on, after bleaching treatment, discs were thoroughly washed and stored in artificial saliva at 37°C in incubator. Chemical analysis was done with energy dispersive spectroscopy (Edx) detector to detect changes in surface composition. Results: Energy dispersive X-ray spectroscopy (Edx) analysis showed no significant difference between all the three groups for Ca% mass (P > 0.99) and Ca% atomic (P > 0.99), C% mass (P = 0.78) and C% atomic (P = 0.76), and O% mass (P > 0.99) and O% atomic (P = 0.28). Similar results were shown for Na, Mg, P, and F. Conclusion: Statistically insignificant effect was observed on enamel composition with both bleaching agents (38% HP and 16% CP).

Background: To evaluate the efficacy of new over-the-counter tooth-whitening products on enamel surface roughness and microhardness. Methods: A total of 120 enamel specimens were prepared and randomly allocated into six groups. Group A was treated with 10% carbamide peroxide; Group B was immersed in distilled water; Group C was treated with hydrated silica, sodium hexametaphosphate toothpaste; Group D was treated with sodium bicarbonate; Group E was treated with 0.25% citric acid; and Group F was treated with hydrated silica, charcoal powder. Results: A, B, and D demonstrated decreased Ra, whereas Groups C, E, and F showed an increased Ra after whitening. The changes in Ra from T0 to T1 in each group was statistically significant (p < 0.001) except for Group B (p = 0.85). The groups showed decreased KHN after whitening, except for specimens in Group B (distilled water). The KHN from T0 to T1 decreased significantly for groups A, C, E, and F (p = 0.001). Significant difference was observed at T1 (p < 0.0001). Conclusion: Within the limitations of this study, it could be demonstrated that surface roughness and enamel microhardness changes were influenced by the type, composition, and exposure time of the whitening product.

Abstract Objectives This randomized, split-mouth, single-blinded trial assessed whether the use of reservoirs in at-home bleaching trays is equivalent to non-reservoir trays. Our choice of an equivalence trial was based on the expectation that a non-reservoir tray is sufficient to produce a color change. Secondary outcomes such as tooth sensitivity (TS) and gingival irritation (GI) were also assessed. Methodology Forty-six patients were selected with canines shade A2 or darker. In half of the patient’s arch, bleaching trays were made with reservoirs and the other half, without reservoirs. At-home bleaching was performed with carbamide peroxide (CP) 10% (3 h daily; 21 days). Color change was evaluated with a digital spectrophotometer (ΔE, ΔE00, and Whiteness Index) and shade guide units (ΔSGU) at baseline, during and one-month post-bleaching. TS and GI were assessed with a numeric scale (NRS) and a visual analog scale (VAS). Results After one month, the equivalence of reservoir and non-reservoir groups were observed in all color instruments (p>0.05). Fifteen and sixteen patients presented pain (absolute risk: 33% and 35%, 95%, confidence interval (CI) 21-46% and 23-49%) in the reservoir and non-reservoir side, respectively. The odds ratio for pain was 0.8 (95%CI 0.2-3.0) and the p-value was non-significant (p=1.0). TS intensity was similar between both groups in any of the pain scales (p>0.05). No difference in the GI was observed (p>0.05). Conclusions The protocol with reservoirs is equivalent in color change to the non-reservoir, although no superiority of the latter was observed in terms of reduced TS and GI with at-home 10% carbamide peroxide bleaching. Clinical Relevance The presence of reservoirs in a bleaching tray did not improve color change or affect tooth sensitivity and gingival irritation.

Abstract Titanium dioxide nanotubes are nanostructures that can accelerate the oxidation reaction of bleaching procedures and promote a more effective whitening effect. Objective This study evaluated physicochemical properties of bleaching agents incorporated with titanium dioxide (TiO2) nanotubes, and the effects on tooth color change at different periods. Methodology 40 premolars were treated according to the following groups (n=10): CP - 10% carbamide peroxide (1 hour daily/21 days); CPN - CP incorporated into TiO2; HP - 40% hydrogen peroxide (three 40-minute sessions/7 days apart); HPN - HP incorporated into TiO2. Color shade was evaluated at five different periods (baseline, after 7, 14 and 21 days of bleaching, and 7 days after end of treatment) according to Vita Classical, CIELab and CIEDE2000 scales. Mean particle size (P), polydispersity (PO) and zeta potential (ZP) were evaluated using dynamic light scattering. Data on the different variables were analyzed by mixed model tests for measures repeated in time (ZP e L*), generalized linear models for measures repeated in time (P, PO, Vita Classical and b*), and Friedman and Mann-Whitney tests (a* and color change/ΔE and ΔE00). Results CP and CPN presented higher P, higher PO and lower ZP than HP and HPN (p≤0.05). All groups showed a significant decrease in Vita Classical color scores after 7 days of bleaching (p0.05) in bleaching time. A significant reduction occurred in the a* and b* values for all the groups, and HPN presented lower a* and b* values (p

In this research, the effect of three bleaching materials, 20% carbamide peroxide, 35% carbamide peroxide and 38% hydrogen peroxide on the solubility of enamel is examined. For this study, 30 premolar teeth extracted for orthodontic purpose were used. They were divided into three groups 10 teeth in each Crowns of the teeth were divided into 2 pieces longitudinally. One part of the tooth crown was used as control and the other part was used as experimental group. 20 percent carbamide peroxide was applied at 370 C during 6 hours for 8 days to the first test group (at-home bleaching), 35 percent carbamide peroxide was applied at 37 0C for 30 minutes for 8 days to the second test group (at-home bleaching) and 38 percent hydrogen peroxide was used 4 times for 15 minutes making a total 60 minutes on the remaining ten specimen (in-office bleaching). The solubility of the enamel was calculated by the determination of inorganic phosphorus using a spectrophotometer. Comparative analysis of the depths in the groups was carried out and its relation with mineral loss was evaluated. Paired t-test was used to compare the differences between the groups. A statistically significant difference was found between the control and the study groups for the 38% hydrogen peroxide. There was no statistically significant difference between the control and experimental groups in the other two groups. It is concluded that of these three bleaching materials, 38% hydrogen peroxide has the greatest effect on mineral loss from the enamel. [Med-Science 2017; 6(1.000): 57-61]

Aims and Objectives: This study aimed to evaluate the effects of at-home and in-office bleaching on the shear bond strength (SBS) of metal, ceramic, and composite orthodontic brackets and to compare their SBSs. Subjects and Methods: A total of 96 human lower premolar teeth were used for this study. Six teeth were used for scanning electron microscopic study while the remaining ninety were divided into three equal groups. Each group was further subdivided into three subgroups with ten samples each. Three protocols were used. In the at-home bleaching group (n = 30), opalescence non-PF (potassium nitrate and fluoride) bleaching agent (10% carbamide peroxide) was applied onto the teeth daily for 14 days and left for 8 h each day. Teeth in the in-office group (n = 30) were treated twice in consecutive days with Opalescence boost PF (40% hydrogen peroxide). After bleaching, the specimens were stored in distilled water for 1 day before bonding. SBS testing was performed on all teeth using Instron universal testing machine. Results: Analysis of variance indicated a significant difference (P < 0.005) among the groups. Maximum SBS was shown by ceramic brackets in control group (Ib) and minimum was shown by composite brackets of in-office bleached group (IIIc). Conclusions: The results showed that at-home bleaching did not affect the SBS significantly whereas in-office bleaching reduced SBS of metal, ceramic, and composite brackets significantly. It is preferable to use metal or ceramic brackets than composite brackets for bonding 24 h after bleaching.

Invisalign has improved periodontal health in comparison to traditional metal wire braces. Due to a growing interest in attaining better teeth esthetics, there are more adults seeking Invisalign treatment. Ten percent carbamide peroxide (CP) breaks down to 6.5% urea and 3.5% hydrogen peroxide, which elevates oral pH, removes stains, and diminishes caries by inhibiting plaque formation. The aim of this study is to investigate whether 10% CP use during Invisalign treatment can enhance tooth shade esthetics while decreasing plaque levels and improving gingival health indices. Twenty-eight patients at Western University dental center undergoing Invisalign were assigned to two groups where the experimental group applied daily bleaching material (10% CP, Ultradent Inc., South Jordan, UT, USA), while the control group did not for 4 weeks. Tooth shade, plaque index (PI), and gingival index (GI) were assessed at baseline and in 2-week intervals for 6 weeks. Results showed that 10% CP had significant change in tooth shade over the 2- and 4-weeks periods (p < 0.05) and significantly reduced plaque and gingival indices (p < 0.05), with minimal to no relapse after 2 weeks post-op. Thus, applying CP at 10% may be a useful application during Invisalign treatment in improving teeth shade and overall gingival health.

Carbamide peroxide (CP), a tooth whitening agent, is chemically unstable. The present study explores stability enhancement of CP by loading in a nanofibrous film (CP-F) composed of polyvinyl alcohol/polyvinylpyrrolidone/silica mixture, using an electrospinning technique. Kept at a temperature range of 60–80 °C for 6 h, CP in CP-F showed significantly higher stability than that in a polymer solution and in water, respectively. Degradation of CP in CP-F could be described by the first order kinetics with the predicted half-life by the Arrhenius equation of approximately 6.52 years. Physicochemical properties of CP-F after long-term storage for 12 months at different temperatures and relative humidity (RH) were investigated using scanning electron microscopy, X-ray diffractometry, differential scanning calorimetry, and Fourier transform infrared spectroscopy. It was found that high temperature and high humidity (45 °C/75% RH) could enhance water absorption and destruction of the nanofibrous structure of CP-F. Interestingly, kept at 25 °C/30% RH, the nanofibrous structure of CP-F was not damaged, and exhibited no water absorption. Moreover, the remaining CP, the mechanical properties, and the adhesive properties of CP-F were not significantly changed in this storage condition. It is concluded that the developed CP-F and a suitable storage condition can significantly improve CP stability.

Burst release of carbamide peroxide (CP) from traditional hydrogels causes severe inflammation to periodontal tissues. The present study explores the development of a novel CP nanoemulgel (CP-NG), an oil-in-water nanoemulsion-based gel in which CP was loaded with a view to controlling CP release. CP solid dispersions were prepared, using white soft paraffin or polyvinylpyrrolidone-white soft paraffin mixture as a carrier, prior to formulating nanoemulsions. It was found that carrier type and the ratio of CP to carrier affected drug crystallinity. Nanoemulsions formulated from the optimized CP solid dispersions were used to prepare CP-NG. It was found that the ratio of drug to carrier in CP solid dispersions affected the particle size and zeta potential of the nanoemulsions as well as drug release behavior and tooth bleaching efficacy of CP-NG. Drug release from CP-NG followed a first-order kinetic reaction and the release mechanism was an anomalous transport. Drug release rate decreased with an increase in solid dispersion carriers. CP-NG obtained from the solid dispersion with a 1:1 ratio of CP to the polymer mixture is suitable for sustaining drug release with high tooth bleaching efficacy and without reduction of enamel microhardness. The developed CP-NG is a promising potential tooth bleaching formulation.

Background. Since it is possible for carbamide peroxide (CP) bleaching agent to contact old amalgam restorations, the present in vitro study evaluated the amount of dissolved mercury released from amalgam restorations with various percent-ages of silver content subsequent to the use of 15% CP. Methods. Thirty ANA 2000 amalgam disks with 43.1% silver content and thirty ANA 70 amalgam disks with 69.3% silver content were prepared. In each group, 15 samples were randomly placed in glass tubes containing 15% CP (as experimental groups) and the remaining 15 samples were placed in buffered phosphate solution (as control groups) with the same 3-mL volume for 48 hours. Subsequently, the amount of mercury dissolved in each test tube was measured using Mercury Ana-lyzing System (Cold Vapor Atomic Absorption, MASLO, Shimadzu, Japan). Data was analyzed with two-way ANOVA and a post hoc Tukey test. (α = 0.05) Results. The amount of mercury released after exposure to CP was significantly higher than that released after exposure to buffered phosphate (P < 0.001). In addition, the amount of mercury released from dental amalgam with a silver content of 43% was significantly higher than that released from dental amalgam with a silver content of 69% (P < 0.001). Conclusion. The amount of mercury release is inversely proportional to the silver content of dental amalgam.

Introduction: Bleaching of discolored tooth may affect the tooth/composite interface. The aim of this study was to evaluate the effect of different concentrations of carbamide peroxide (CP) on the marginal seal of composite restorations bonded with a self-etch adhesive. Materials and Methods: In this experimental study Class V cavities were prepared on the buccal and lingual surfaces of 24 intact extracted human molar teeth with gingival margins in dentin and occlusal margins in enamel. The cavities were restored using the adhesive system Clearfil SE Bond and the composite Filtek Z250. Finally, they were randomly divided into four groups (1 control and 3 bleached groups). The control group was kept for two weeks in distilled water at 37° C. The bleached groups were bleached with 10%, 22% and 35% CP gel for 8 hours a day for 14 days. After that, the samples were immersed in 0.5% fuchsin solution and sectioned. Then gingival microleakage was graded. Data was analyzed using Kruskal Wallis and Mann Whitney U test (Pvalue≤0.05). Results: Microleakage was observed in the gingival wall of all groups. There was a significant difference between the control group and the bleached groups. Microleakage in the 22% bleached group was less than the other concentrations, but this difference was not significant. Conclusion: Bleaching with different concentrations of CP can increase the microleakage of the gingival wall of Composite restorations bonded with clearfil SE Bond self-etch adhesive and does not recommend.

Background: Bleaching has gradually became a popular procedure for people searching for aesthetic improvement. The aim of this in vitro study was to investigate the effect of bleaching with 45% carbamide peroxide on the level of mineralization of enamel, using laser fluorescence. Materials and methods: Sixty extracted human teeth were treated with 45% carbamid peroxide (Opalescence, Ultradent), 4 consecutive days for one hour each day. The effect of the bleaching agent on the level of mineralization of enamel was measured with DIAGNO dent pen. The statistical method we use was descriptive analysis. Results: The average values, measured before the applications of the carbamid peroxide were 6.33. On the first day they were 5.41, on the second 5.38, on the third 5.11 and 5.35 on the forth. Conclusion: There was observed a slight remineralization effect due to the incorporated Ca2+ and F- ions in the bleaching agent that we have used.

Objectives: To evaluate the effect of concentration and influence of reservoirs on the gingival mucosa of patients submitted to at-home bleaching with 10% and 35% carbamide peroxide (cp). Materials and Methods: A total of 20 patients were submitted to home bleaching with a 10% cp gel for 2 h/day for 3 weeks and 35% cp gel for 30 min/day for 3 weeks (n = 10). The custom-made mouth trays were made with a reservoir on only the left side and cut anatomically 1 mm beyond the gingival margin. Smears of the gingival mucosa were obtained by the exfoliation cytology in liquid media technique before (control), immediately after, and 30 and 45 days after the treatment. The samples were processed in the laboratory and evaluated for inflammation. Statistical analysis was carried out by McNemar test, two proportions test, independent paired t-test, and Wilcoxon test with a level of significance of 1%. Results: The presence of a reservoir in the custom tray resulted in an increase of inflammation immediately after the bleaching procedure. No significant differences were found in the degree of inflammation between the two groups at different period of observations. (P > 0.01). Conclusion: Ten percent and 35% cp bleaching gel caused gingival inflammation immediately after the procedure and persisted until 45 days after the bleaching treatment. The use of a reservoir in the custom tray for home bleaching resulted in higher rates and higher intensity of gingival inflammation.

Purpose: This in vitro study was done to evaluate the effect of a 10% carbamide peroxide bleaching agent on the micro hardness of three types of direct resin-based restorative materials. Materials and Methods: Fifteen disk-shaped specimens (5.0 mm diameter and 2.0 mm depth) of each material, including a micro hybrid resin composite (Z250), a nanofilled resin composite (Z350), a hybrid resin composite (Z100), were fabricated and then polished with medium, fine, and superfine polishing discs. After being polished, specimens were cleaned with distilled water for 2 min in an ultrasonic bath to remove any surface debris and then stored in distilled water at 37ΊC for 24 hours. Specimens from each material were divided into three groups (n=5). One group was selected as a control group (non treated with bleaching agent). The other two groups were treated with bleaching agent for 14 days (group A) and followed by immersion in artificial saliva for 14 days (group B). The top surfaces of the specimens in the different groups were also subjected to the Vickers hardness test with a load of 300 g and 15-second dwell time. Data were analyzed witha one-way analysis of variance and Turkey′s HSD test (α = 0.05). Results: There was a general reduction of Vickers hardness numbers (VHN) values of treated groups compared with the control group for each material used, but this reduction was minimal, with no significant difference between groups in Z250, whereas the other two materials (Z350, Z100) showed a significant reduction of VHN of treated groups compared with the control group. Conversely, the findings showed no significant difference between treated groups A and B in all materials used. Conclusion: A 10% carbamide peroxide bleaching agent had an adverse effect on the micro hardness of nanofilled and hybrid types of resin-based composite materials compared with the micro hybrid type.

In recent years, there has been an increased demand for improvement in the appearance of natural teeth. The conservative technique of tooth bleaching has gained attention and acceptance from both patients and clinicians. Despite increased popularity, there is controversy surrounding the adverse effects of bleaching on dental restorative materials. This article reviews the effects of bleaching agents on major categories of dental restorative materials and provides evidence-based recommendations to the clinicians and researchers. Current literature reveal that bleaching might have a detrimental effect on restorative materials. However, because of the variability in experimental design, there is a lack of consensus concerning the bleaching effects on restorative materials. A standardized and reproducible guideline for assessment of bleaching effects on restorative materials needs to be established and verified by future studies.

Carbamide peroxide (CP) possesses a strong tooth bleaching activity, however, its clinical application is limited because of its instability in aqueous formulations. This study explores the improvement of CP stability and bleaching activity by loading CP in electrospun nanofibrous film (ENF). Polyvinylalcohol, polyvinylpyrrolidone, and silica were used as components for core-based nanofibers of ENF. Electrospinning feed aqueous solutions (EFASs) were developed for preparing CP loaded ENF (CP-ENF). Stability of CP in EFASs is significantly higher than in pure water. The highest stability of CP is found in PPS-CP3, composed of 0.5% CP, 5.5% polyvinylalcohol, 3% polyvinylpyrrolidone, and 1% silica. The results from X-ray diffraction indicate that CP is dispersed as a non-crystalline form in CP-ENFs. CP and the compositions of EFASs play a major role on characteristics and bleaching efficiency of CP-ENFs. Drug release of CP-ENFs is the first order kinetics. CP-ENF obtained from PPS-CP3 shows the highest drug entrapment efficiency, high adhesion, and suitable sustained release. Drug release mechanism is along with anomalous transport according to Korsmeyer–Peppas model. In an ex vivo study using human teeth, it shows the highest bleaching efficiency among the others. Therefore, CP-ENF obtained from PPS-CP3 is a promising ENF for clinical use.

Background: Dental bleaching has become an everyday procedure for treating teeth presenting discoloration, as a therapy on its own or as a part of restorative dentistry. The most widely used bleaching products available for vital teeth are hydrogen peroxide and carbamide peroxide, marketed as a range of products adapted to different treatment modes. The purpose of the study was to evaluate the clinical whitening efficacy of four high-concentration bleaching products for vital teeth applied in single in-office sessions. Methods: This clinical trial included 40 patients divided into four groups according to the concentration of the hydrogen peroxide-based (HP) product used (Group 1: HP 35%; Group 2: HP 37.5%; Group 3: HP 38%; Group 4: HP 40%). Each patient received one in-office whitening treatment of maxillary and mandibular anterior teeth (incisors, canines, and premolars), making a total of 791 teeth. The color changes produced in central incisors and canines were measured. Results: All groups underwent significant color changes from initial to final evaluations for color parameters L*, a*, and b*. No significant differences between the four groups were found for either the L* or a* parameters. Analysis of the b* parameter found significant differences between the HP 38% group and the HP 35% group. No significant differences in ΔE were found between the four groups (ANOVA p = 0.174). HP 38% obtained the highest ΔE (4.63), while HP 40% obtained 4.01. Conclusions: A single in-office whitening session, regardless of the bleaching product used, modifies tooth color effectively. All four products achieved increases in the L* parameter and significant reductions in parameters a* and b*. The ΔE did not show significant differences between the four groups. In-office whitening with high concentration hydrogen-peroxide-based products was found to be an effective treatment for moderate and severe dental discoloration.

Background: In cases of moderate to severe dental discoloration, vital tooth whitening usually requires a prolonged treatment time if it is to obtain satisfactory outcomes. Variations in the clinical efficacy of whitening products in terms of their concentration and application time mean that we need to be aware of the real bleaching capacity of each whitening method and each product. This randomized clinical trial aimed to analyze with a spectrophotometer the effect of the number of in-office vital tooth whitening sessions (one or two) on the number of weeks of ensuing home whitening until color stability was obtained. Methods: Twenty patients with moderate/severe discoloration were treated with combined vital tooth whitening. Ten patients were treated with a single in-office session consisting of two applications of a product containing 40% hydrogen peroxide, followed by home treatment with individualized splints and a 16% carbamide peroxide gel (Group 1S). The other ten patients (Group 2S) were treated in two in-office sessions with two applications of the same product as Group 1S, followed in the same way by home treatment. Results: Comparing the two groups (1S and 2S), no significant differences in Euclidean distance (ΔE) were found after in-office whitening, or when color stabilization was obtained and home whitening ceased. Significant differences in the number of weeks of home whitening until color stabilization reached the same outcomes were found between 1S and 2S; 1S required a mean of 11.6 weeks home whitening, while 2S required 8.2 weeks. Conclusions: Combined tooth whitening with two in-office sessions significantly reduces the number of weeks (by three to four weeks) of subsequent home tooth whitening needed to reach color stabilization.

Carbamide peroxide as a whitening agent for teeth is very popular because the use of this agent is easy and inexpensive. There are two kinds of concentrations, i.e. 10%-15% and 35%. The methods are home bleaching and in office bleaching. For home bleaching, the duration of whitening application is 2-6 weeks, each day for 8 hours, whilst for in office bleaching, two hour application will be required. Whitening efficacy might be increased up to 2-5 levels and the color may sustain for 1-3 years, and this treatment could be reapplied. There is an effect on pulp system, but the effect is reversible, i.e. sensitivity which could be treated with fluoridation or application of potassium nitrate. The side effects on gingiva include inflammation which is caused by the buffer and is only temporary. Bleaching is safe to be use and the result will be satisfying if proper procedure is followed.

Background: Bleaching can affect the mechanical properties of enamel-dentin complex, such as flexural strength. Casein phosphopeptide-amorphus calcium phosphate (CPP-ACP) is often used following bleaching treatment to reduce hypersensitivity and to increase demineralization of tooth. Purpose: The purpose of the study was to investigate the effect of CPP-ACP on the flexural strength of enamel-dentin complex following extracoronal bleaching. Methods: Forty-eight enamel-dentin plates (size 8 x 2 x 3 mm) were randomly assigned into 6 groups, each consisted of 8 samples. Group 1, no bleaching and immersed in artificial saliva. Group 2, no bleaching, CPP-ACP application only. Group 3, bleaching using 15% carbamide peroxide. Group 4, similar to group 3, except application of CPP-ACP for the times between bleaching. Group 5, bleaching with 40% hydrogen peroxide. Group 6, similar to group 5, except application of CPP-ACP for the times between bleaching. Flexural strength of each enamel-dentin plate was tested by threepoint bending test using universal testing machine. Results: The results showed that 15% carbamide peroxide and 40% hydrogen peroxide significantly reduced flexural strength of enamel-dentin (216.25±26.44 MPa and 206.67±32.07 MPa respectively). Conversely, application of CPP-ACP following both bleachings increased flexural strength (266.75± 28.27MPa and 254.58±36.59 MPa respectively). A two-way Anova revealed that extracoronal bleaching agents significantly reduced flexural strength (pConclusion: Extracoronal bleaching agents reduce flexural strength, whereas application of CPP-ACP following bleaching either with 15% carbamide peroxide or 40% hydrogen peroxide can increase the flexural strength of enamel-dentin complex.

Objective: This study aimed to evaluate the effect of whitening toothpastes and mouthrinses on the color stability of teeth bleached with 16% carbamide peroxide (CP) after immersion in coffee solution. Materials and methods: Specimens obtained from bovine incisors were bleached with 16% CP for 14 days. After bleaching, the specimens were stained in coffee solution for 24 h and randomly divided into eight groups according to the following products (n = 10): distilled water (control group, DW), Scope White mouthrinse (SW), Crest 3D White mouthrinse (CWR), Crest 3D White toothpaste (CWT), Crest 3D White toothpaste and Crest 3D White mouthrinse (CWT + CWR), Listerine Whitening toothpaste (LWT), Listerine Whitening mouthrinse (LWR), and Listerine Whitening mouthrinse and Listerine Whitening toothpaste (LWR + LWT). Color measurements were conducted using a spectrophotometer. The data were assessed by analysis of variance for repeated measures and Tukey’s multiple comparison test (p 3.46). The whitening effect of CWR on teeth stained after bleaching was significantly greater than that in the other groups (p 0.05). The combination of mouthrinse and toothpaste did not increase the degree of tooth whitening. Conclusion: Whitening mouthrinse and toothpaste had similar effects on the control group in terms of whitening of teeth stained after bleaching. Nevertheless, Crest 3D White mouthrinse produced the greatest recovery whitening effect among all the products tested.

Aim : The aim of the study was to evaluate and compare the efficacy of commercially available three bleaching agents when used internally or by internal-external method in non-vital teeth. Materials and Methods: Seventy extracted single-rooted premolars were artificially stained with whole blood in centrifugal machine. Teeth were divided into six experimental groups (Group I-VI) and one control group (Group VII). Bleaching was carried out in all the experimental groups using either of three commercially available bleaching agents: In Group I and group IV, 35% carbamide peroxide was used. In group II and V, 21% carbamide peroxide was used. Teeth in Group III and VI were bleached using 35% hydrogen peroxide (H 2 O 2 ). In the first three experimental groups (Group I, II, III), internal bleaching was done and in other three groups (Group IV, V, VI), both internal and external application was done. The evaluation was done at 0, 7, and 14 days using VITA shade guide. Statistical Analysis: The results obtained were statistically analyzed using ANOVA, Paired t-test, and ANOVA with post hoc Tukey′s modification to evaluate the significant change and efficacy of the groups tested. Results: All bleaching agents showed effective shade reduction. The effects of 35% H 2 O 2 and 35% carbamide peroxide were statistically similar. The least reduction was seen with 21% carbamide peroxide groups. There was no difference between internal bleaching and internal-external methods. Conclusions: Within the limitation of the study, it could be concluded that 35% carbamide peroxide is an effective intracoronal bleaching agent similar to that of 35% H 2 O 2 .

Background and Aim: Tooth-colored restorations are the current strategy for treatment of aesthetically unpleasant brown spots (BSs). Considering the importance of conserva-tive dentistry, this study aimed to assess the effect of resin infiltrant (RI) and casein phosphopeptide amorphous calcium phosphate (CPP-ACP) after the application of 20% carbamide peroxide (CP) on BS color parameters in the esthetic zone. Materials and Methods: This experimental study was conducted on 70 extracted sound human teeth with BSs. The specimens were first subjected to the application of 20% CP and were then randomly divided into two groups of CPP-ACP and RI. Specimens were subjected to colorimetry before the intervention, after bleaching and after the application of RI or CPP-ACP using a spectrophotometer. Data were statistically analyzed using SPSS version 20, paired t-test, independent t-test and repeated measures ANOVA with P0.05) howev-er, the L* significantly increased (p0.05). Com-parison of the two groups revealed that only the color change (ΔE) during the bleaching procedure was significant (p0.05). Conclusion: Based on the results, aesthetically unpleasant BSs on teeth may be treated using a bleaching agent along with RI or CPP-ACP. RI seems to have a superior efficacy in increasing the translucency compared to CPP-ACP.

ObjectivesThe aim of this study was to verify the promoting effect of carbamide peroxide on dimethylbenzanthracene (DMBA)-induced carcinogenesis in the hamster buccal pouch, in order to reduce the period of latency for tumor formation.MethodsSixteen hamsters were randomized into two groups of eight animals each. The hamsters of the group I had their right buccal pouches treated with 0.5% DMBA and 10% carbamide peroxide teeth bleaching gel for 55 days. The animals of the group II had their right pouches treated only with DMBA. After, six animals of each group had their pouches prepared for light microscopy. Histomorphometry was performed to assess the presence of keratinization, nuclear polymorphism, pattern of invasion, number of blood vessels, and inflammatory infiltrate in the tumor front. Furthermore, the newly formed lesions were graded according the Bryne's grading system. The remaining animals had the vascular system of the pouches casted by Mercox and qualitatively analyzed by scanning electron microscopy.ResultsHistopathological analysis of the buccal pouches treated with DMBA and carbamide peroxide exhibited formation of squamous cell carcinoma well-differentiated with a high degree of malignancy in all pouches. The development of this neoplasm was associated with a significant increase in the number of blood vessels, presence of keratin pearls, and inflammatory infiltrate. The pouches of the group II showed inflammation, epithelial hyperplasia, dysplasia, and squamous cell carcinoma in only three right pouches. The analysis of the electron micrographs of the pouches chemically inducted with DBMA and carbamide peroxide reveled formation of a new vascular network characteristic of squamous cell carcinoma.ConclusionThe protocol presented here, using DMBA associated with carbamide peroxide, shortens the period of latency to produce squamous cell carcinoma in the hamster buccal pouch, decreasing the time and costs of the experiments.

Introduction. Bond between composite materials and bleached teeth depends on the change of micro-morphological structure of enamel and dentin after the application of bleaching agent. Bleaching procedure can weaken adhesion of composite materials to hard tissues, where even just a presence of hydrogen peroxide may affect their polymerization. The aim of this study was to determine bond strength of composite materials after internal teeth bleaching using 30% carbamide peroxide. Material and Methods. The study was conducted on 20 extracted, endodontically treated human teeth. After internal teeth bleaching with 30% carbamide peroxide a class V cavity was prepared and restored with Tetric EvoCeram nanocomposite material. Microleakage was determined using dye method (silver nitrate) and measured on the incisal and gingival walls using stereoloupes. Results. Linear dye penetration on the incisal wall (7.25 μm) of bleached teeth was greater than on the incisal wall in non-bleached (control group) teeth (5.75 μm) but with no statistically significant difference. Dye penetration on the gingival wall of bleached teeth (20.00 μm) was greater than on the gingival wall of the control group (14.25 μm). This difference was statistically significant (p

Discolouration of teeth, especially the anteriores, can result in considerably cosmetic impairment in person. Combine effects of intrinsic and extrinsic colour determines the appearance of teeth. Whitening of teeth with bleaching is a more conservative therapeutic method than full crowns, veneers or composite restorations which is more invasive and expensive. Among bleaching techniques, in office bleaching with carbamide peroxide provide superior aesthetic result in short period of time with no adverse effects. This paper presents case series of tooth discolouration in non-vital tooth which was successfully bleached using 35 % carbamide peroxide. After 1 year follow up the prognosis was good with no reversal of tooth discolouration. This case report allows the better understanding of the concept of nonvital tooth bleaching with carbamide peroxide which gives a non-invasive alternative for aesthetic purpose in preserving the natural tooth structure.

Teeth discoloration is mainly treated with dental bleaching. Use of chemical bleaching has side effects, so it is important to find an alternative natural dental bleaching agent. Averrhoa bilimbi contains peroxide and oxalate acid that possess tooth whitening properties. Objective: To determine the change in color of dental enamel after the application of Averrhoa bilimbi and 10% carbamide peroxide. Methods: Samples were 20 post-extracted of the two tested materials premolars (10 specimens each for Averrhoa bilimbi and carbamide peroxide application). After the application, the specimens were incubated at 37ºC for 2 hours, washed and soaked in aquadest before further incubated for another 14 days. The colour changed was observed by 5 independent observers using shade guide. Results: Quantitative and qualitative analyzes were performed. Qualitatively, A3 color has changed into C1, A2, D2, B2 and B1 in the Averrhoa bilimbi group. A more significant color change in the 10% carbamide peroxide group (p=0.005) compared to Averrhoa bilimbi group (p=0.005) were observed. The difference of resulted enamel colour change was statistically significant (p=0.002). Conclusion: Averrhoa bilimbi had a good prospect as dental bleaching agent since its application effectively resulted in a slight enamel colour change although its whitening properties was still lower than 10% carbamide peroxide.DOI: 10.14693/jdi.v19i3.134