Nonvital tooth bleaching: a review of the literature and clinical procedures

Efficiency of Teeth Bleaching after Regenerative Endodontic Treatment: A Systematic Review

The aim of this review is to evaluate of effectiveness of bleaching procedures used to treat discolored teeth subsequent to regenerative endodontic procedures (REPs) based on the review of in vitro and in vivo studies. This literature review was carried out according to the PRISMA guidelines. Four databases (PubMed, Scopus, the Cochrane Library, and Web of Science databases) were searched electronically, until 30 January 2020 without a year limit. The quality of studies was assessed using a modified methodological index for non-randomized studies. After analyzing 1405 studies, 6 in vitro and 9 in vivo studies were eligible for this review. In in vitro studies, effectiveness of bleaching was assessed in teeth discolored by antibiotic pastes, blood, and barrier materials in various combinations. In all analyzed studies, bleaching was effective in teeth discolored by antibiotic pastes as well as by blood and barrier materials. Of 26 treated teeth in the in vivo studies, 17 teeth were bleached successfully. In six cases, there was improvement of the shade. In three cases, bleaching was not sufficient. Bleaching material, techniques, and times differed between studies. Whitening of discolored teeth after REPs is achievable. However, to establish precise guidelines, further long-term clinical studies should be performed.

Conservative esthetic management of post orthodontic treatment discolored tooth with calcified canal: a case report

A case of pulp canal obliteration (PCO) two years after the completion of orthodontic treatment is presented. Post orthodontic treatment PCO is a rare finding. A 23 years old female presented with the discoloration of clinical crown of maxillary right central incisor. Radiographic examination revealed the calcified canal and diffused periapical radiolucency. Vitality tests were negative. A decision was made to do root canal treatment followed by the walking bleaching. After the successful completion of the root canal treatment the internal bleaching was performed. The discolored tooth showed significant improvement in color. Internal bleaching is a viable conservative treatment for improving esthetics in single non vital discolored tooth.

Comparison of MTA, CEM Cement, and Biodentine as Coronal Plug during Internal Bleaching: An In Vitro Study

BACKGROUND

Internal bleaching is a choice of treatment in discolored endodontically treated teeth. Cervical root resorption is one of the important complications of this treatment. A suggested procedure to prevent this type of resorption is using a coronal barrier under the bleaching materials. The aim of the study was to compare the microleakage of mineral trioxide aggregate (MTA), calcium-enriched mixture (CEM) cement, and Biodentine.

MATERIALS AND METHODS

In this in vitro study, a total of 60 single canal incisors were included. They were randomly divided into three experimental groups (n = 16), one positive control group (n = 6), and one negative control group (n = 6). Coronal portion of the canals in the experimental groups was sealed with 3 mm of MTA, CEM cement, or Biodentine as a coronal barrier. After 3 days, specimens were bleached. A fresh Enterococcus faecalis suspension was added to the samples. The culture tubes were observed for 45 days, and the daily turbidity was recorded. Statistical analysis was accomplished by the Kaplan-Meier test and SPSS 22.

RESULTS

All positive samples showed turbidity, whereas none of the negative samples allowed bacterial leakage. Results showed no significant difference between MTA, CEM cement, and Biodentine groups. (P value = 0.304, 0.695, and 0.217). The bacterial microleakage for the two groups also did not show significant differences.

CONCLUSIONS

CEM cement and Biodentine showed promising results as coronal plug, and clinical studies are needed to test these materials with MTA for avoiding microleakage in internal bleaching treatment.

Coronal Tooth Discoloration After the Use of White Mineral Trioxide Aggregate

Mineral trioxide aggregate (MTA) has been used in regenerative procedures but observations have indicated that with its use there is dark staining of the tooth structure. This case report describes the treatment of tooth discoloration caused by white mineral trioxide aggregate (WMTA). Revascularization was performed with the use of WMTA in the upper left central incisor. Grayish discoloration appeared 9 months later, the tooth necessitating internal bleaching of the tooth. A significant improvement was observed in the crown after internal bleaching. The choice of material should not rely solely on biological and functional aspects, but aesthetic considerations should also be taken into account. The patient needs to be advised of risks, benefits, and alternatives to internal bleaching, eg, a veneer or a crown. Coronal discoloration is a significant distraction and embarrassment for many people in achieving an aesthetic smile; thus, it must be corrected at the earliest possible stage of discoloration.

Minimally invasive technique for non-vital tooth bleaching using traditional Japanese paper

The purpose of this case report is to describe a minimally invasive technique for non-vital tooth bleaching using traditional Japanese paper, known as washi. Non-vital tooth bleaching with a mixture of sodium perborate and 30% hydrogen peroxide rolled in Japanese paper for a traumatically injured tooth, and in-office vital-tooth bleaching for the upper front six teeth and first premolars, were performed. Five-year follow-up showed satisfactory stability in the bleaching effects and did not show any problems in the traumatically injured tooth. The use of Japanese paper for non-vital tooth bleaching may minimize damage to discolored non-vital teeth.

Novel in-office peroxide-free tooth-whitening gels: bleaching effectiveness, enamel surface alterations, and cell viability

To evaluate the bleaching ability, the effect on enamel surface and cytotoxicity of novel tooth-whitening formulations containing papain, ficin, or bromelain. Forty bovine dental discs (6 cm ×4 cm) were pigmentated and randomly allocated into the following groups (n = 10): Group 1, 20 wt% carbamide peroxide (control); group 2, 1% papain-based whitening; group 3, 1% ficin-based whitening; and group 4, 1% bromelain-based whitening. The whitening gels were prepared and applied on the enamel three times per day once a week, for 4 weeks. Color measurement was obtained by CIEDE2000. Enamel Knoop microhardness and roughness were evaluated. The WST-1 assay was used to evaluate the cell viability of mouse fibroblast cells (L929). Data were statistically analyzed by one-way analysis of variance (ANOVA) and Student Newman Keuls's post hoc test at α = 0.05 significance level. Bromelain, ficin-based, and carbamide peroxide bleaching gels showed a similar color change (p < 0.001). Higher enamel hardness decrease and higher enamel roughness were caused by the carbamide peroxide (p < 0.05). The experimental whitening gels did not affect cell viability. Tooth bleaching gels containing bromelain, papain, or ficin have substantial clinical potential to be used in the development of peroxide-free tooth whitening gels.

Bleaching of severely darkened nonvital tooth case report-48 months clinical control

OBJECTIVE

To record in detail, the long-term success of a bleaching treatment employing hydrogen peroxide in a severely darkened tooth.

CLINICAL CONSIDERATIONS

Tooth discoloration is an important aesthetic complain of patients. Because it is a relatively common condition, different materials and techniques capable of restoring the tooth color in a minimally invasive, conservative, and longstanding manner were developed. In this case, it was used the association between mediate (walking bleach) and immediate (internal/external) bleaching techniques using hydrogen peroxide as the main agent.

CONCLUSION

The association of techniques was a conservative therapeutic solution to restore the natural color of the right upper central incisor, which was darkened after an endodontic treatment performed more than twenty years ago. The bleaching protocol used presented no risk to the patient, such as cervical resorption and the color was stable over a 48 months period, showing the success of the protocol proposed for this case.

CLINICAL SIGNIFICANCE

There is a possibility to severely darkened teeth receive an adequate bleaching treatment protocol, which can successfully restore the aesthetics and natural color in a conservative and long lasting way.

Effects of Bioactive Agents on Dentin Mineralization Kinetics After Dentin Bleaching

Objectives:

This study evaluated effects of Bioglass 45S5 (BG) and Biosilicate (BS) remineralization on the chemical composition and bond strength of control dentin (CD) and bleached dentin (BD) surfaces.

Methods and Materials:

Dentin bleaching treatment was performed using the walking bleaching technique with 0.01 g of sodium perborate and 0.5 mL of 3% hydrogen peroxide for 14 days. Remineralization treatment was carried out by rubbing a remineralization solution (0.015 g of BG or BS diluted in 1.35 mL of distilled water) on the etched dentin surface for 30 seconds. Micro-Raman spectroscopy (MRS) was used to quantitatively analyze the mineral matrix ratios of CD and BD (n=5) after remineralization treatment with BG and BS over 15 days of incubation in artificial saliva. The CD and BD discs (n=10) with and without remineralization treatment with BG and BS were restored using a two-step etch-and-rinse adhesive system (Optibond S, Kerr) and five layers of 1-mm-thick composite resin (Filtek Z250, 3M ESPE). The restored dentin discs were sectioned into nine bonded beams with cross-sectional areas of approximately 0.9 mm2 and tested for microtensile bond strength (μTBS). The dentin surface of one fractured beam per tooth was submitted to MRS to characterize the physicochemical composition (n=10) at the interface. The data were analyzed using one-way analysis of variance and the Tukey-Kramer post hoc test (p&lt;0.005).

Results:

MRS bioactive analyses revealed that both BG and BS promoted increased mineral matrix ratios in the CD and BD. Significantly higher μTBS values were found after CD treatment with BG (CD: 57 MPa±11; CD-BG: 78 MPa±15) and when BG and BS were applied to the BD (BD: 42 MPa±5; BD-BG: 71 MPa±14; BD-BS: 64 MPa±11) (p&lt;0.005). The MRS analysis of the fractured dentin beam showed that the remineralization treatment significantly increased the dentin relative mineral concentration and promoted the appearance of new interface peaks, indicating a chemical interaction (p&lt;0.005).

Conclusion:

Remineralization of BD is an effective therapy to restore damage caused by dentin bleaching and acid conditioning. This approach not only increases dentin mineral compounds but also improves dentin's ability to interact chemically with the adhesive system.

The association of external cervical resorption with modern internal bleaching protocols: what is the current evidence?

Internal bleaching is an effective and minimally invasive way of bleaching non-vital teeth. A commonly cited risk associated with it is external cervical resorption (ECR), which is a potentially significant complication that could result in loss of the tooth. This is an important point of discussion with a patient during the consent process. Legally, patients are required to be made aware of material risks to which they would be likely to attach significance, such as the loss of a tooth. The risk of ECR is therefore a key component in the patient's decision-making process as they weigh it against the perceived benefits. Over the last ten years, both clinical and legal reasons have resulted in a number of changes in the materials and protocols used for internal bleaching. This leads to the question of what the current quality of evidence is regarding the association of ECR following internal bleaching with modern protocols. Other restorative options for discoloured teeth, such as veneers or crowns, involve the irreversible removal of tooth tissue and these may be chosen by patients over internal bleaching based on out-of-date evidence.

Effects of 16% Carbamide Peroxide Bleaching on the Surface Properties of Glazed Glassy Matrix Ceramics

Objective

To determine the influence of the home bleaching agent, Opalescence PF, on the surface roughness and microhardness of glazed glassy matrix CAD-CAM ceramics. Materials and Methods. The 28 sintered leucite- and lithium disilicate-reinforced ceramic specimens (IPS Empress CAD and IPS e.max CAD) were divided into control and bleached groups. The home bleaching agent was applied to specimens of bleached groups for 7 days. The surface roughness and microhardness of all specimens were measured. A scanning electron microscope was used to evaluate the surface properties. The data were statistically analyzed by two-way ANOVA.

Results

The control e.max CAD showed the lowest surface roughness values. For both Empress and e.max CAD, surface roughness was significantly higher for the bleached group (p < 0.05). No significant differences in microhardness were observed.

Conclusions

According to our study, patients should be careful when using home bleaching agents because whitening agents can affect the mechanical properties of full ceramic restorations like e.max CAD and Empress CAD. Ceramic polishing may be required in clinical situations where ceramic restorations are accidentally exposed to bleaching gels.

Tooth discoloration caused by endodontic treatment: A cross-sectional study

INTRODUCTION

This cross-sectional study evaluated the influence of endodontic filling material, cervical limit of root filling, and tooth location on the color variation (∆E₀₀ ) from 1 to 60 months of follow-up.

MATERIALS AND METHODS

Color records were obtained from 70 participants who received 83 endodontic treatments. CIEL*a*b* color coordinates were measured on the homologous tooth, which was considered as baseline, and on endodontic treated teeth with a spectrophotometer. ∆E₀₀ was calculated by the CIEDE2000 method at three conditions (condition 1: homologous tooth vs endodontically treated tooth after ≤1 month; condition 2: homologous tooth vs endodontically treated tooth after >1-12 months; condition 3: homologous tooth vs endodontically treated tooth after >12 months up to 5 years) for each variable. The zinc oxide and eugenol mineral trioxide aggregate or resin-based filling materials, dental cervix or ≥2 mm in the apical direction cervical limit of root filling and anterior or posterior tooth location were considered in the comparisons. Confidence intervals for the means (95% CI) were calculated, ∆E₀₀ values and CIEL*a*b* individual color coordinates were compared for each pair of variables using the Student t test or Welch test (α = .05).

RESULTS

Greater ∆E₀₀ values were generally observed in the condition 3 for cervical limit (∆E₀₀ = 10.7), use of zinc oxide and eugenol and mineral trioxide aggregate-based filling materials (∆E₀₀ = 10.7), and anterior teeth (∆E₀₀ = 12.4). Only in the condition 1, the ∆E₀₀ values of the filling materials did not show statistical differences (P = .198).

CONCLUSIONS

Higher ∆E₀₀ values were yielded from zinc oxide and eugenol and mineral trioxide aggregate-based filling materials, anterior teeth, and dental cervix cervical limit of root filling.

CLINICAL SIGNIFICANCE

Tooth discoloration yielded by endodontic materials and procedures is a challenge to clinical practice resulting in aesthetic problems and discomfort to both patient and professional, especially when it occurs in anterior teeth.

Six-month Follow-up of the Effect of Nonvital Bleaching on IL-1β and RANK-L: A Randomized Clinical Trial

Objectives:

It has been reported that bleaching generates an increase in the activity of osteoclasts in vitro. We quantified the RANK-L and IL-1β biomarkers in a double-blind, randomized clinical trial evaluating the in vivo effect of hydrogen peroxide (35%) and peroxide carbamide (37%) six months after whitening.

Methods and Materials:

Fifty volunteers participated, each with color change in a nonvital tooth. Fifty teeth were randomly divided into two groups (n=25), and the teeth were bleached using either 35% hydrogen peroxide (G1) or 37% carbamide peroxide (G2). Intracoronal bleaching was carried out by a technical “walking bleach” over four sessions. Gingival crevicular fluid samples were collected and used to quantify the IL-1β and RANK-L secreted levels. Samples of six periodontal sites (three vestibular and three palatal) were collected for up to six months (at the beginning of the study [baseline] and at one week, one month, and six months posttreatment). The color change was visually monitored using the Vita Bleached Guide (ΔSGU).

Results:

Comparing each time to baseline assessment, a significant increase in the levels of IL-1β and RANK-L across time points was detected (p&lt;0.05). The color change was 4 in G1 and G2, and a statistically significant difference (p&lt;0.05) was found at the month time point between the groups. Using the Spearman test, a strong correlation (&gt;0.8) between the IL-1β and RANK-L levels in both groups at all time points was detected.

Conclusions:

Nonvital bleaching using a technical walking bleach induces an increase in the IL-1β and RANKL production in periodontal tissues, which persists for six months after treatment. Both biomarkers were highly correlated in both groups and at all time points.

Effect of Bleaching and Ca(OH)2 Dressing on the Bond Strength of Fiberglass Posts to Root Dentine

Objective The purpose of this study was to evaluate the effect of the intracoronary bleaching and calcium hydroxide (Ca(OH) ₂ ) dressing use, on the bond strength (BS) of fiberglass posts to root dentine.

Materials and Methods After root canal filling of 40 bovine incisors, a 2-mm thick cervical plug was fabricated 2 mm below the cementum–enamel junction. Seven days later, teeth were randomly distributed into four groups ( n = 10), as follows: G1 no bleaching, followed by immediate post cementation; G2 bleaching and immediate post cementation; G3 bleaching, dressing with Ca(OH) ₂ for 7 days, and post cementation; and G4 bleaching, no dressing, and post cementation after 7 days. The roots were transversally cut into 1-mm thick slices to perform the push-out test (0.5 mm/min). Failure modes were assessed under scanning electron microscopy.

Statistical Analysis The analysis of variance (two-way ANOVA) was performed, followed by the supplementary Tukey multiple comparison test ( a = 5%).

Results No significant difference for BS was observed among groups. Considering the different root thirds, G1 had higher BS values for the cervical third in comparison with the apical one ( p < 0.05). The most frequent failure modes were adhesive between cement/dentine (G1); cohesive at the post (G2 and G3), and mixed (G4).

Conclusions The BS of the fiberglass posts to root dentine was not affected by the intracoronary bleaching and the use of Ca(OH) ₂ dressing.

The Use of Composite Layering Technique to Mask a Discolored Background: Color Analysis of Masking Ability After Aging—Part II

The aim of this study was to evaluate the effectiveness of the layering technique to mask a discolored background (C4) after one year of water aging. The technique was used with three resin composite restorative systems (IPS Empress Direct, Charisma Diamond, and Filtek Z350XT). Ninety 1.5-mm-thick specimens were divided into groups and subgroups according to the restorative system and resin composite shade combination used in the layering technique (enamel, body, and dentin). The color measurements were made by reflection spectrophotometer (SP60, EX-Rite) over the C4 substrate at two time points: after 24-hour water immersion (T0) and after one-year water aging (T1). The masking ability was evaluated by calculating the ΔE between an inherent color background and a C4 background at T0 and T1. CIELAB and CIEDE2000 formulas were used for comparative analysis between T0 and T1 color measurements. Analysis of variance and Turkey's post hoc test (a=0.05) were performed to analyze ΔEab and ΔE00 mean values. The Z350XT restorative system presented adequate masking ability in the combinations of 0.5 mm body + 1.0 mm dentin, 0.5 mm enamel + 1.0 mm dentin, and 1.5 mm dentin after 24-hour water immersion. The masking ability was affected negatively by water aging in most of the combinations. The IPS Empress Direct was the only system that remained stable after aging in the combinations of 0.5 mm enamel + 1.0 mm dentin and + 1.5 mm dentin (p=0.05 and p=0.47 for CIELAB; p=0.15 and p=0.51 for CIEDE2000), although it did not present adequate masking ability in both time points. None of the combinations of any system presented adequate masking ability after prolonged water aging.

Effect of sodium ascorbate on bond strength and metalloproteinases activity in bleached dentin

Aim

This study evaluated the effect of sodium ascorbate (SA) on the proteolytic activity of matrix metalloproteinases (MMPs) and investigated the related effects on the bond strength of bleached dentin.

Materials and methods

Eighty freshly extracted human third molars were randomly divided according to treatment (bleaching or SA application), type of analysis (microshear or measuring MMP activity), and post-bleaching time to assess bond strength (24 hrs or 30 days). Data from both analyses were subjected to one-way analysis of variance to detect differences among groups, followed by Tukey’s multiple comparison test (p≤0.05).

Results

Dental bleaching significantly reduced bond strength values when the adhesive strategy was performed after 24 hrs (despite the SA treatment) or 30 days after the bleaching procedure. However, after 30 days, the bond strength values of the groups who received bleaching or SA application were similar to those of the unbleached group. Dental bleaching caused the activation of MMPs, and SA did not influence this activity.

Conclusion

It was concluded that SA does not affect the activity of MMPs or the bond strength in bleached dentin immediately after the bleaching treatment.

Effect of Er: YAG Laser on Microtensile Bond Strength of Bleached Dentin to Composite

Introduction: In non-vital tooth bleaching, dentin is in direct contact with the bleaching agent, 1 to 3-week delay is needed to eliminate free radicals from tooth structure. The present study aimed to evaluate the effect of irradiation of Er: YAG laser on immediate microtensile bond strength of bleached dentin to composite. Methods: Sixty sounds human teeth were collected and randomly divided into 4 groups (n=15): no bleaching (NB), opalescence endo hydrogen peroxide (HP) gel bleaching, sodium perborate (SP) bleaching and laser bleaching with heydent gel (LB). The groups were divided into 3 subgroups (n=5): no surface treatment, Er: YAG laser irradiation and 10% sodium ascorbate (SA). All samples were restored and underwent microtensile bond strength testing. Statistical analysis was carried out using one-way and two-way ANOVA. Results: Bond strength in NB-SA group had a significant difference with the NB group (P<0.05) while no significant difference was noted between NB and NB-Er groups (P=0.55). Application of SA and Er: YAG laser after bleaching with SP did not enhance the bond strength (P=0.07). Conclusion: Application of SA and Er: YAG laser after HP gel bleaching significantly enhanced the bond strength. Application of Er: YAG laser after internal bleaching with HP gel could enhance the bond strength.

Congenital erythropoietic porphyria with erythrodontia: A case report

BACKGROUND

The causes for intrinsic tooth discoloration can be separated into two categories as systemic and local. Systemic causes are either genetic or drug-induced effects. The development of dentition can also be affected by a number of systemic factors and metabolic diseases such as porphyria. Congenital erythropoietic porphyria (CEP), also known as Gunther's disease, is a metabolic disease caused by a transformation in the gene that codifies uroporphyrinogen-3 synthesis, leading to porphyrin aggregation in urine, skin, bone, and dentin.

CASE REPORT

A 21-month-old girl with erythrodontia was referred to Paediatric Dentistry Department in September 2017. A physical examination revealed blisters on her face, nose, hands, and feet. Laboratory findings showed highly elevated urine total uroporphyrin and total coproporphyrin I and III levels. Next-generation sequencing multigene panel testing for porphyria demonstrated a homozygous c.10C>T (p.L4F) mutation in the UROS gene. For curative therapy, the patient was admitted to the allogeneic bone marrow transplantation program.

CONCLUSION

Congenital erythropoietic porphyria most commonly presents in the first few years of life. Manifestations can include reddish-colored urine, skin blistering, scarring, and erythrodontia. A timely diagnosis can prevent undesirable skin findings of the disease and death due to hematological involvement before a curative allogeneic bone marrow transplantation is performed.

Effects of endodontic irrigants on blood and blood-stained dentin

Objectives

This study aimed to investigate bleaching effects of common endodontic irrigants on human whole blood and blood-stained dentin. Specifically, it was assessed whether sodium hypochlorite at a clinically recommended concentration (2.5% NaOCl) would bleach with similar efficacy as a peroxide-based irrigant at higher molarity (5% H₂O₂). Furthermore, the effects of a NaOCl-compatible chelator with a high affinity to iron (Dual Rinse HEDP) were investigated.

Methods

Human whole blood was mixed at a 1:20 ratio with either phosphate-buffered saline, 9% HEDP, 2.5% NaOCl, 2.5% NaOCl containing 9% HEDP, or 5% H₂O₂. Effects were assessed spectrometrically and photographically. Human dentin specimens were prepared with a methacrylate reservoir for liquids and a polished assessment side over 1 mm dentin thickness. Dentin was stained using human whole blood for 3 weeks and subsequently exposed to the irrigants for 60 min. Measurements were performed in the CIELAB color space. Results were compared using parametric tests with the alpha-type error set to 5%.

Results

When directly exposed, the solutions containing NaOCl completely discolored the blood, while the 5% H₂O₂ exerted a bleaching effect without complete dissolution of dissolved matter, and the pure 9% HEDP had no effect at all. The NaOCl solutions bleached blood-stained dentin more efficiently than H₂O₂ (p < 0.05).

Conclusions

Under the current conditions, the 2.5% NaOCl solution had a stronger bleaching effect on blood and blood-stained dentin than 5% H₂O₂. HEDP did not have any direct impact on blood color or NaOCl-derived bleaching.

Deionized water can substitute common bleaching agents for nonvital tooth bleaching when treated with non-thermal atmospheric plasma

The bleaching efficacy of common bleaching agents and deionized water treated with non-thermal atmospheric pressure plasma in the pulp chamber for nonvital tooth bleaching was evaluated. A total of 120 extracted human maxillary first incisors were stained using human blood. Teeth were randomly divided into eight groups (n = 15). In the first four groups, teeth were bleached using 35% hydrogen peroxide gel, 37% carbamide peroxide gel, 2:1 (w/v) sodium perborate paste, and deionized water for 30 min. In the remaining groups, bleaching agents were treated with non-thermal atmospheric plasma for 5 min inside the pulp chamber. Overall color changes (∆E) were determined using Commission Internationale de L'Eclairage Lab Colour System. The plasma-assisted tooth bleaching has not increased tooth temperature beyond 37°C. Bleaching efficacies of bleaching agents were significantly improved when treated with non-thermal atmospheric plasma compared to their application (P < 0.05). A remarkable bleaching effect was obtained when bleaching agents were substituted with water and when treated with non-thermal atmospheric plasma. Non-thermal atmospheric plasma treatment could be a novel tool for activation of bleaching agents in the pulp chamber for nonvital tooth bleaching procedure. Moreover, water could be used as a novel bleaching agent when treated with the non-thermal atmospheric plasma to eliminate possible risks which might arise from peroxide-containing agents.

Effects of intracoronal bleaching agents on the surface properties of mineral trioxide aggregate

Bleaching agents may affect surface properties of mineral trioxide aggregate (MTA) as a coronal barrier. The purpose of this study was to investigate surface properties of MTA after exposure to intracoronal bleaching agents. MTA was set in acrylic molds with a 4 mm high central hole and a 6 mm diameter. Specimens were divided into four groups (n = 10); three groups were exposed to bleaching agents three times on every fourth day (carbamide peroxide-CP, hydrogen peroxide-HP, sodium perborate-SP) and a control group-C. The surface roughness and Vickers surface microhardness were measured. Differences between groups were analyzed using a Kruskal-Wallis test and intergroup comparisons were assessed with a Mann-Whitney U test with a Bonferroni correction (p < 0.0001). The microstructure and elemental composition were observed using a scanning electron microscope (SEM) and an energy-dispersive X-ray microanalysis (EDX) system. In terms of microhardness, the decrease in the HP group was significantly greater than that of the CP and SP groups; CP group significantly greater than that of the SP group, however, there was no significant difference between the SP and C groups. Surface roughness values were compared between groups, and no significant differences were observed between the CP and HP groups, and they exhibited significantly higher roughness values than the SP and C groups. SEM/EDX showed that the bleaching agents affected the elemental distribution. Bleaching agents adversely affected the surface roughness, surface microhardness and elemental distribution of MTA, with exposure to SP causing fewer changes on the surface properties than CP or HP.

Impact of Carbamide Peroxide Whitening Agent on Dentinal Collagen

Carbamide peroxide (CP) is widely used as a tooth-whitening agent in self-administered tooth-bleaching products. In this study, the effects of 5% and 10% CP on dentinal collagen structure and chemical properties were evaluated in vitro. Thirty-five intact teeth were exposed to 2 whitening protocols (2 or 4 h daily) with either 5% or 10% CP gel for 1 wk. Shade changes before and after the whitening protocol were captured colorimetrically using a spectroshade. Collagen scaffold models and demineralized dentine disc samples were prepared and exposed to CP droplets (5% or 10%). Structural changes were investigated using electron microscopy. Finally, mineralized dentine disc samples were prepared postbleaching to assess chemical changes resulting from CP exposure in dentinal collagen using Raman spectroscopy. Results showed a difference in tooth shade when exposed to 5% and 10% CP whitening protocols, with a significantly ( P ≤ 0.01) greater change reported for the 10% CP/4-h group. Imaging of the collagen scaffold model following exposure to CP showed a gelatinization process indicating that the free radical by-products from CP are able to disrupt the quaternary structure of noncrosslinked collagen. The most significant damage on the collagen scaffold was seen for the 10% CP exposure for 4 h. Imaging of the demineralized discs displayed the same glassy amorphous layer appearance as found in the collagen scaffold. Raman spectra of the mineralized dentine discs showed a significant decrease ( P ≤ 0.01) in the integrated area of amide I and amide III values in the 4 test groups following CP application. Amide I was more affected as both the exposure time and concentration of CP increased. Despite the claimed safety of whitening agents, this in vitro study concludes that even low concentrations of CP result in a deleterious change in dentinal collagen.

Molecular damage and responses of oral keratinocyte to hydrogen peroxide

BACKGROUND

Hydrogen peroxide (H₂O₂)-based tooth bleaching reagents have recently increased in popularity and controversy. H₂O₂ gel (3%) is used in a Nightguard for vital bleaching; transient tooth sensitivity and oral mucosa irritation have been reported. Genotoxicity and carcinogenicity have also been significant concerns.

METHODS

We used primary cultured normal human oral keratinocytes (NHOKs) as an in vitro model to investigate the pathological effects to mitochondria functions on human oral keratinocytes exposed to different doses of H₂O₂ for different durations.

RESULTS

An MTT assay showed compromised cell viability at a dose over 5 mM. The treatments induced nuclear DNA damage, measured using a single-cell gel electrophoresis assay. A real-time quantitative polymerase chain reaction showed H₂O₂ induced significant increase in mitochondrial 4977-bp deletion. Mitochondrial membrane potential and apoptosis assays suggested that oxidative damage defense mechanisms were activated after prolonged exposure to H₂O₂. Reduced intracellular glutathione was an effective defense against oxidative damage from 5 mM of H₂O₂.

CONCLUSION

Our study suggests the importance for keratinocyte damage of the dose and the duration of the exposure to H₂O₂ in at-home-bleaching. A treatment dose ≥100 mM directly causes severe cytotoxicity with as little as 15 min of exposure.

Evaluation of biochemical changes in dental tissues after different office bleaching methods

The color of the teeth is an important topic for many people and can be influenced by intrinsic and extrinsic stains. There is an increasing demand for whitening of the teeth year by year. The most popular way of whitening is "bleaching," which is the result of the breakdown of pigments located in the enamel and/or the dentin, caused by reactive oxygen species (ROS) released from bleaching agents. These bleaching agents could increase matrix metalloproteinase (MMP)-mediated collagen degradation in dentin. The aim of this study was to compare biochemical changes and oxidative stress levels of the human premolar dentin-pulp complex after three different bleaching methods containing hydrogen peroxide (H₂O₂) bleaching agents. Individuals, whose first four premolars were extracted for orthodontic purposes, included into the study. Group 1-Laser: bleaching gel containing 46% H₂O₂ (LaserWhite20 whitening gel, Biolase Technology Inc., San Clemente, CA, USA) and a diode laser activation (Ezlase 940 nm system). Group 2: 35% H₂O₂ containing whitening gel (Whiteness HP Maxx, FGM) and halogen light source activation (Optilux 501, Kerr, Orange, CA, USA). Group 3: 35% H₂O₂ containing whitening gel (Whiteness HP Maxx, FGM). Group 4-Control: No whitening treatment. According to the test results, there were no significant differences among groups in the values of cathepsin B and MMP proteolytic activities ( p > 0.05). The total ROS values released from the dentin tissue were higher than those obtained from the pulp tissue ( p < 0.05). There were significant differences among the bleaching groups in the ROS values released from the dentin tissue.

The effect of bleaching agents on the compressive strength of calcium silicate-based materials

The present study aimed to evaluate the effect of sodium perborate on the compressive strength of calcium silicate-based materials. ProRoot wMTA, MTA Plus, NeoMTA Plus and Biodentine discs with 5 mm thickness and 4 mm diameter were prepared. Thirty discs from each material were used for compressive strength testing and divided into two groups: control and bleaching (n = 15). The sodium perborate was mixed with 30% hydrogen peroxide in a creamy consistency and placed on the surface of the specimens. Specimens were tested in an Instron machine, and compressive strength values were recorded and compared. The data were analysed using one-way anova and post hoc Tukey tests. Compressive strength of all tested materials significantly decreased after bleaching (P < 0.05). SEM examination revealed deterioration on materials' surfaces after bleaching. Application of sodium perborate and hydrogen peroxide reduced the compressive strength of ProRoot wMTA, MTA Plus, NeoMTA Plus and Biodentine.

Effect of Different Intraorifice Barriers and Bleaching Agents on the Fracture Resistance of Endodontically Treated Anterior Teeth

INTRODUCTION

Intraorifice barriers (IOBs) are usually used before internal bleaching for coronal sealing and the prevention of cervical resorption. The aim of this study was to investigate the effect of different IOBs on the fracture resistance (FR) of endodontically treated anterior teeth bleached with various bleaching agents (BAs).

METHODS

After performing root canal treatment for 72 extracted bovine upper incisors, the coronal 3 mm of gutta-percha was removed, and samples were classified into 3 based on the type of IOB: calcium-enriched mixture, mineral trioxide aggregate, and resin-modified glass ionomer. After applying IOBs, samples of each group were subdivided into 4 based on the BA: carbamide peroxide 45% (CP), hydrogen peroxide 35% (HP), sodium perborate (PB), and distilled water as the control. At the end of bleaching, the access cavities were restored with composite resin. The FR was measured with a universal testing machine at a crosshead speed of 5 mm/min. The data were analyzed using 2-way analysis of variance and least significant difference post hoc tests (P < .05).

RESULTS

The effect of BAs on the FR was significant (P < .05); however, the effect of the IOB and the interactive effect of these variables were not significant (P > .05). The FR in the HP and PB groups was significantly different from the control (P < .05) but that of CP was not significantly different from the control (P > .05).

CONCLUSIONS

Mineral trioxide aggregate and calcium-enriched mixture act similarly to resin-modified glass ionomer as an IOB. CP, unlike HP and PB, did not significantly decrease the FR.

Quality of life and stability of tooth color change at three months after dental bleaching

PURPOSE

Intracoronary bleaching is a minimally invasive, alternative treatment that addresses aesthetic concerns related to non-vital teeth discoloration. However, to the best of our knowledge, no studies have assessed the psychosocial impacts of such procedures on patients' aesthetic perceptions. The aim of this study was to evaluate aesthetic perceptions and the psychosocial impact of patients up to 3 months after their teeth had been bleached with hydrogen peroxide (35%) and carbamide peroxide (37%) using the walking bleach technique.

METHODS

The patients were randomly divided into two groups according to the bleaching agent used: G1 = hydrogen peroxide 35% (n = 25) and G2 = carbamide peroxide 37% (n = 25). Non-vital bleaching was performed in four sessions. Color was objectively (ΔE) and subjectively (ΔSGU) evaluated. Aesthetic perception and psychosocial factors were evaluated before, 1 week and 1 month after the bleaching using the Oral Health Impact Profile (OHIP) and Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ) questionnaires.

RESULTS

The color change (ΔE) values at 1 month were G1 = 16.80 ± 6.07 and G2 = 14.09 ± 4.83. These values remained stable until the third month after treatment (p > 0.05). There was a decrease in the values of OHIP-aesthetics and PIDAQ after treatment versus baseline (p < 0.05). This status was maintained through the third month after treatment.

CONCLUSIONS

Both agents were highly effective and had a positive impact on the aesthetic perception and psychosocial impact of patients, values that also remained stable over time. Non-vital bleaching yields positive and stable impacts on aesthetic perception and psychosocial factors. ClinicalTrials.gov identifier NCT02718183.

Color Regression and Maintenance Effect of Intracoronal Whitening on the Quality of Life: RCT-A One-year Follow-up Study

OBJECTIVE:

This randomized clinical study evaluated two parameters: 1) the clinical color rebound of whitening patients' tooth discoloration using the walking bleaching technique and 2) the impact on psychological and aesthetic self-perception at the one-year follow-up of patients who underwent bleaching of nonvital teeth.

METHODS AND MATERIALS:

Fifty study participants with nonvital tooth discoloration were recruited. Teeth were assigned randomly into one of two groups: 1) 35% hydrogen peroxide (n=25) and 2) 37% carbamide peroxide (n=25). Intracoronal bleaching was carried out over the course of four sessions using the walking bleach technique. Tooth color was evaluated after each session in order to measure the total color variation (ΔE). The guide was arranged from highest (B1) to lowest values (C4) for evaluating color, and color changes using Vita Classical Shade (ΔSGUs) units were calculated. Subjective and objective assessments were compared with the counterpart of the tooth. Aesthetic perception and psychosocial factors were evaluated before and after treatment by the Oral Health Impact Profile (OHIP) and Psychological Impact of Dental Impact Questionnaire (PIDAQ) surveys.

RESULTS:

Color changes (ΔE) were 15.48 ± 5.17 and 14.02 ± 4.85 for carbamide and hydrogen peroxide groups, respectively. There were no significant differences ( p>0.05) between these two groups at the one-year follow-up. There was a decrease in the PIDAQ scores after treatment compared to baseline values ( p<0.05). The majority of OHIP values regressed to baseline values.

CONCLUSION:

The technique of walking bleaching was highly effective and showed minimal color rebound in nonvital teeth and had a positive effect on patients' psychological impact at the one-year follow-up.

Protocols for sodium ascorbate application on intracoronary dentin bleached with high-concentrated agent

Purpose:

Composite resin restorations are normally replaced after the internal bleaching of endodontically treated-teeth because the bleaching agent does not alter the color of the restorative material. This study evaluated the effect of 10% sodium ascorbate (SA) applied at different protocols on bleached dentin.

Materials and Methods:

One-hundred slabs of intracoronary bovine dentin were divided into 5 groups: 2 controls-GI without bleaching (positive), GII bleached with 35% hydrogen peroxide (HP) (negative); and 3 experimentals – GIII. 35% HP + SA at protocol 1 (dripping, washing and drying the solution), GIV. 35% HP + SA at protocol 2 (dripping and aspirating the solution) and GV. 35% HP + SA at protocol 3 (dripping, rubbing and aspirating the solution). Sixty fragments were restored and subjected to shear bond strength test (n = 12). Forty fragments (n = 8) were prepared for chemical analysis (energy dispersive X-ray spectrometry) and surface morphology (scanning electron microscopy). Data were analyzed by ANOVA and Tukey test (P < 0.05).

Results:

GI (3.169 ± 1.510a) had the highest means values, similar to GIV (2.752 ± 0.961a) and GV (2.981 ± 1.185a) (P < 0.05). Inferior values were obtained in GII (1.472 ± 0.342b) and GIII (2.037 ± 0.742ab) had intermediate values (P > 0.05). Oxygen concentration was reduced in groups treated with SA, and the surface exhibited residual granules of the solution.

Conclusion:

The 10% SA solution reestablishes the bond strength of restorative material to bleached dentin, especially if active protocols of application and aspiration were used.

Does the Use of a "Walking Bleaching" Technique Increase Bone Resorption Markers?

OBJECTIVE

This randomized clinical trial evaluated the effect of 35% hydrogen peroxide in comparison with 37% carbamide peroxide in a nonvital bleaching technique of "walking bleaching" (four sessions of treatment) on periodontal markers: nuclear factor kappa B-ligand (RANK-L-process of root resorption marker) and interleukin 1β (IL-1β-inflammatory response marker).

METHODS AND MATERIALS

Fifty volunteers presenting with discoloration of nonvital teeth and endodontic treatment in good condition participated. Fifty teeth were randomly divided into two study groups according to bleaching gel: HP = 35% hydrogen peroxide (n=25) and 37% carbamide peroxide (n=25). Nonvital bleaching was performed with a walking bleaching technique consisting of four sessions of bleach application. Gingival crevicular fluid samples were taken in order to quantify the RANK-L and IL-1β levels by enzyme-linked immunosorbent assay. Samples were obtained from six periodontal sites for each bleached tooth: three vestibular and three palatine (mesial, middle, and distal) at seven time periods: baseline, after each of the four sessions of nonvital bleaching, at one week, and at one month after nonvital bleaching. Tooth color variations were analyzed in each session by VITA Bleachedguide 3D-MASTER (ΔSGU).

RESULTS

Significant increments in the RANK-L and IL-1β levels were detected in each evaluated time compared with baseline ( p<0.05); however, no differences were detected between hydrogen peroxide and carbamide peroxide on increments of the biomarkers studied. The change of color was effective for both nonvital bleaching therapies ( p<0.05).

CONCLUSIONS

Nonvital bleaching induced a significant increment in the RANK-L and IL-1β levels in periodontal tissues around bleached, nonvital teeth.

A colourimetric evaluation of the effect of bacterial contamination on teeth stained with blood in vitro: Evaluation of the efficacy of two different bleaching regimes

BACKGROUND

Tooth discolouration could occur due to bacterial contamination in traumatized teeth. Hydrogen peroxide is the commonly used bleaching agent. However, due to concerns over safety, alternative bleaching regimes such as sodium perborate (S) and thiourea-hydrogen peroxide (T) have been investigated.

METHODS

Apices resected and pulp extirpated 99 premolars were divided into two groups. Group 1 and 2 was injected with blood and blood/bacteria, stored anaerobically for 35 days. The two groups were treated by bleaching with water, S or T. Teeth were rebleached after 7 days. Colourimetric evaluation was assessed using digital imaging, CasMatch standardization and CIE L*a*b colour system preoperatively, 35 days of staining and 7 and 14 of bleaching. A linear mixed model with fixed effects of time, group and bleach was used to examine colour difference.

RESULTS

Blood-stained teeth were significantly redder and darker on day 35 compared with blood/bacteria-stained teeth. After bleaching, blood-stained teeth retained significant redness compared with blood/bacteria-stained teeth using either S or T. T produced a significantly whiter shade in both the groups after 14 days.

CONCLUSIONS

Blood-stained teeth were significantly darker and red compared with blood/bacteria-stained teeth. T bleaching regime was more effective than S.

Effectiveness and effect of non-vital bleaching on the quality of life of patients up to 6 months post-treatment: a randomized clinical trial

OBJECTIVES

The aim of this study was to evaluate the esthetic perception of patients at 6 months after bleaching of non-vital teeth with 35% of hydrogen peroxide and 37% of carbamide peroxide using a walking bleach technique. We also assessed psychosocial impacts as well as the clinical effectiveness and stability of the color change.

MATERIALS AND METHODS

The teeth bleaching treatment was randomly assigned to two groups according to the bleaching agent used: G1 HP = 35% of hydrogen peroxide (n = 25) and G2 CP = 37% of carbamide peroxide (n = 25). The non-vital bleaching was performed in four sessions using the walking bleach technique. The color was objectively (ΔE) and subjectively (ΔSGU) evaluated. The esthetic perception and psychosocial factors were evaluated before treatment as well as one and 6 months post-treatment using Oral Health Impact Profile (OHIP) esthetics and Psychosocial Impact of Dental Esthetics Questionnaire (PIDAQ).

RESULTS

The color change (ΔE) at 6 months (G1 = 14.53 ± 5.07 and G2 = 14.09 ± 6.61) for both color groups remained stable until the 6-month post-treatment (p > 0.05). There was a decrease in the values of OHIP esthetics and PIDAQ after treatment compared to the baseline (p < 0.05), and this effect was maintained 6 months post-treatment.

CONCLUSIONS

Both agents were highly effective and maintained the color stability at 6 months; this positively affected the esthetic perception and psychosocial impact of patients who also remained stable over time.

CLINICAL RELEVANCE

Non-vital bleaching produces a positive and stable impact on the esthetic perception and psychosocial factors at medium-term follow-ups.

Impact of 35% Hydrogen Peroxide on Color and Translucency Changes in Enamel and Dentin

Abstract This study evaluated the effects of tooth bleaching with high-concentration of hydrogen peroxide on alterations of translucency parameter (TP) and color of dentin and enamel. The crown of five human molars was sectioned into four slices parallel to buccal surface. The dentin of external slices containing buccal/ lingual enamel was fully removed with diamond bur; while these slices were used to assess alterations on enamel. Alterations on dentin were assessed into the center of internal slices. The color of specimens was measured over white and black backgrounds using a spectrophotometer (CieL*a*b) at baseline, allowing to calculate the TP by difference between the color measured over each background. Specimens were submitted to three 15-min applications of 35% hydrogen peroxide followed by their storage in water for one-week. Afterwards, the color measurements were repeated at both backgrounds. Color (∆L, ∆a, ∆b and ∆E) and translucency (∆TP) changes were calculated and data individually analyzed by T-test (α = 0.05). Influence of hard tissue and assessment time on each color parameter was also analyzed by 2-way repeated measure ANOVA (α = 0.05). Tooth bleaching resulted in increased lightness for the enamel, whereas no alteration on this parameter occurred for dentin. No difference between the tooth hard tissues was observed regards the other color parameters and ∆E. A slightly reduction on TP was observed only for the enamel. In conclusion, 35% hydrogen peroxide caused similar color and translucency changes on dentin and enamel.

Influences of Light-emitting Diode Illumination Bleaching Technique on Nanohardness of Computer-aided Design and Computer-aided Manufacturing Ceramic Restorative Materials

AIM

This study evaluated the effect of light-emitting diode (LED) illumination bleaching technique on the surface nanohardness of various computer-aided design and computer-aided manufacturing (CAD/CAM) ceramic materials.

MATERIALS AND METHODS

Twenty disk-shaped samples (width, length, and thickness = 10, 15, and 2 mm) were prepared from each of the ceramic materials for CAD/CAM, including Lava™ Ultimate (L_V), Vita Enamic® (E_n) IPS e.max® CAD (M_e), inCoris® TZI (I_C), and Prettau® zirconia (P_r). The samples from each type of ceramic were randomly divided into two groups based on the different bleaching techniques to be used on them, using 35% hydrogen peroxide with and without LED illumination. The ceramic disk samples were bleached according to the manufacturer's instruction. Surface hardness test was performed before and after bleaching using nanohardness tester with a Berkovich diamond indenter.

RESULTS

The respective Vickers hardness number upon no bleaching and bleaching without or with LED illumination [mean ± standard deviation (SD)] for each type of ceramic were as follows: 102.52 ± 2.09, 101.04 ± 1.18, and 98.17 ± 1.15 for L_V groups; 274.96 ± 5.41, 271.29 ± 5.94, and 268.20 ± 7.02 for E_n groups; 640.74 ± 31.02, 631.70 ± 22.38, and 582.32 ± 33.88 for M_e groups; 1,442.09 ± 35.07, 1,431.32 ± 28.80, and 1,336.51 ± 34.03 for I_C groups; and 1,383.82 ± 33.87, 1,343.51 ± 38.75, and 1,295.96 ± 31.29 for P_r groups. The results indicated surface hardness reduction following the bleaching procedure of varying degrees for different ceramic materials. Analysis of variance (ANOVA) revealed a significant reduction in surface hardness due to the effect of bleaching technique, ceramic material, and the interaction between bleaching technique and ceramic material (p < 0.05).

CONCLUSION

Bleaching resulted in a diminution of the surface hardness of dental ceramic for CAD/CAM. Using 35% hydrogen peroxide bleaching agent with LED illumination exhibited more reduction in surface hardness of dental ceramic than what was observed without LED illumination.

CLINICAL SIGNIFICANCE

Clinicians should consider protection of the existing restoration while bleaching.

Effect of cleaning protocols on bond strength of etch-and-rinse adhesive system to dentin

Aim

This study aimed to evaluate the cleaning protocol of dentin impregnated with epoxy resin-based sealer (AH Plus) and the effects on the adhesive interface using 95% ethanol (E) or formamide solution (F) associated with microabrasion with glass microparticles (M).

Methodology

Forty dentin specimens were impregnated with sealer (AH Plus). Specimens were cleansed according to the following protocols (n = 10): G1 (E); G2 (F); G3 (E = M); and G4 (F = M). No treatment was performed in G5 (control). Specimens were subjected to standard error of the mean to evaluate the residues persistence (×500) and open dentinal tubules counting (×2000). Another fifty specimens were subjected to similar procedures and cleaning protocols. Seven days later, composite-resin-made specimens were performed on dentin using etch-and-rinse adhesive system, then submitted to microshear test.

Results

G2 and G4 showed higher residues' persistence and lower incidence of open dentinal tubules than G1 and G3 (P < 0.05). No difference was found between G1 and G3 or G2 and G4 (P > 0.05). Adhesive system bond strength was similar in all groups (P > 0.05).

Conclusions

Microabrasion negatively affected the epoxy resin-based sealer residues' removal protocols' action; all groups presented residues on the dentin surface. However, 7 days later, the protocols did not affect the bond strength of adhesive system to sealer-impregnated dentin.

Effects of Erbium Family Laser on Shear Bond Strength of Composite to Dentin After Internal Bleaching

Introduction: The aim of this study was to assess the effect of surface treatment with erbium: yttrium-aluminum-garnet (Er:YAG) and erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) lasers on shear bond strength of composite resin to recently bleached dentin. Methods: In this study, 40 extracted human premolars were selected. The teeth were cut 4 mm apical to the cusp tip and were randomly divided into four groups (n=10 in each group) for shear bond strength testing. For bleaching, 35% hydrogen peroxide (H2 o2 ) gel (Opalescence Endo, Ultradent, South Jordan, UT, USA) was applied to dentin surfaces of all specimens for 10 days. Before etching and bonding, in Er,Cr:YSGG and Er:YAG laser groups, dentin surfaces were irradiated with Er,Cr:YSGG and Er:YAG lasers, respectively. In Er,Cr:YSGG group, Er:YAG group and control group, composite restoration was performed immediately after bleaching while in common procedure group, composite restoration was performed after seven days. The teeth were then subjected to shear bond strength testing machine. The data were statistically analyzed using analysis of variance (ANOVA) and Tukey test. Results: The mean and standard deviation (SD) of shear bond strength was 4.3 ± 1.4 MPa for control group, 6.7 ± 2.0 Mpa for Er,Cr:YSGG group, 14.4 ± 3.7 Mpa for Er:YAG group and 19.4 ± 2.6 Mpa for common procedure group. Conclusion: The shear strength of composite to Er:YAG laser-treated bleached dentin was significantly higher than control group while significantly lower than common procedure.

Effectiveness and Impact of the Walking Bleach Technique on Esthetic Self-perception and Psychosocial Factors: A Randomized Double-blind Clinical Trial

OBJECTIVE

This trial evaluates the impact of psychosocial and esthetic self-perceptions of patients undergoing nonvital tooth bleaching using the walking bleach technique. We also assessed the clinical effectiveness of bleaching tooth discoloration.

METHODS

Fifty volunteers with nonvital tooth discoloration were enrolled. Teeth were randomized into two groups: 35% hydrogen peroxide (n=25) and 37% carbamide peroxide (n=25). Intracoronal bleaching was performed over four sessions using the walking bleach technique. Tooth color was evaluated at each session to measure total color variation. The shade guide was arranged from highest (B1) to lowest (C4) values to assess the color and calculate the color change in the number of shade guide units. Subjective and objective assessments were compared with the tooth counterpart. Esthetic self-perception and psychosocial factors were assessed before and after treatment.

RESULTS

Color change was 15.48<5.17 for hydrogen peroxide and 14.02<4.85 for carbamide peroxide. There was no significant difference at any time point (p>0.05) except at sessions 3 and 4 (p<0.05). Overall, whitened teeth values were similar to those of counterpart teeth (p>0.05). There was a decrease in Oral Health Impact Profile and Psychosocial Impact of Dental Esthetics questionnaire scores after treatment compared with baseline (p<0.05).

CONCLUSION

The walking bleach technique was highly effective on nonvital teeth and had a positive effect on self-esthetic perception and psychological impact for the patients.