Influence of daily usage times on patients' compliance during at-home bleaching: a randomized clinical trial.

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.

Biomechanical performance of three fiberglass post cementation techniques: Imaging, in vitro, and in silico analysis.

PURPOSE: The structural integrity of the resin cement layer, the bond strength, and the biomechanical behavior of different fiberglass post cementation techniques were evaluated. METHODS: Thirty-three bovine incisors were divided into three groups (n = 11): conventional fiberglass post (CFP), conventional fiberglass post in flared root canals (CFL), and relined fiberglass post (RFP). Six specimens from each group were submitted for high-resolution microcomputed tomography (µCT) to evaluate the integrity and presence/volume of voids at the resin cement layer. Finite element analysis (FEA) of two three-dimensional (3D) models of each group were conducted, one considered ideal (without interface defects) and another containing the conditions identified in the µCT analysis. Push-out bond strength tests were conducted for all specimens. RESULTS: The CFL group had the greatest mean values of void (Thirds cervical: 73.67; middle: 95.67; apical: 47.33) and gap concentration (Thirds cervical: 14.67; middle: 15.83; apical: 8.33) compared with CFP and RFP. A significant difference in bond strength was observed between the cervical (1.33 MPa) and middle thirds (1.85 MPa) compared with the apical third (4.85 MPa) of the CFL. A significant difference was observed in the bond strength in the CFL (1.33 MPa) and RFP (3.29 MPa) in the cervical third, which were statistically similar to the bond strength of the CFP. The tensile stress distributions were similar in most structures, localized in the cervical region on the lingual surface. CONCLUSIONS: Structural defects in the interface layer might influence the bond strength and biomechanical behavior under the different fiberglass post cementations.

Influence of daily usage times on patients' compliance during at-home bleaching: a randomized clinical trial

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.

Use of auxiliary devices during retreatment of direct resin composite veneers.

The removal of direct composite veneers, when the retreatment is necessary, represents a challenge to the clinician, since the healthy dental structure must be preserved. Thus, the aim of this study was to compare the accuracy provided by different auxiliary devices during retreatment of direct composite veneers. Seventy-five bovine teeth were prepared for direct composite veneers, scanned (T1), and restored. Specimens were divided into 5 groups for retreatment: conventional high-speed handpiece without auxiliary device (WD); high-speed handpiece with a white LED (WL); high-speed handpiece with an UV light (UL); electric motor and multiplier 1/5 handpiece (EM); and conventional high-speed handpiece using magnifying loupe (ML). After retreatments, other scanning was performed (T2). Changes on dental wear or composite residues areas, as well as, the average between wear and presence of residues were measured. Data were submitted to Kruskal-Wallis and Dunn's post-test (p≤ 0.05). There were greater areas of wear for ML, being statistically superior to WD and EM groups. The ML presented smaller residues areas, being statistically lower than the WD and EM groups. Regarding the average between wear and the presence of resin residues, additional wear occurred after re-preparation, regardless of the group. Magnifying loupe promoted greater areas of wear and smaller areas of resin residues than conventional high-speed handpiece and electric motor. Both techniques using light accessories did not differ from other ones.

Repair bond strength and degradation of glass ionomer cements after mechanical and chemical challenges

Aim: Little is known about the reparability of glass ionomer cements (GICs) after storage in acid environments. The aim of this study was to evaluate the solubility and repairability of GICs immersed in acid solutions and subjected to brushing. Methods: Thirty discs of each GIC (Vitremer, VitroFil LC, VitroFil, and Maxxion R) were divided into three immersion groups: distilled water, Coca-Cola, or hydrochloric acid (HCl), then subjected to brushing. The weight of discs was measured before and after the immersions to determine mass alteration. Each disc was repaired, by adding the same brand of GIC over its surface. After immersing the repaired specimens in same solutions, shear bond strengths using universal testing machine were measured. Two-way ANOVA and Tukey's test was used (α=0.05). Results: Resin-modified GICs degrade after HCl immersion followed by brushing (p<0.05), while self-cured GICs were negatively affected by all challenges (p<0.05). The challenges decreased the repair strength for VitroFil LC (p<0.05), which had higher repair shear bond strength than the other GICs (p<0.05), exhibiting most cohesive failures. Conclusion: Self-cured GICs degraded when immersed in all acid solutions with brushing while resin-modified GICs only degraded following HCl immersion with brushing. Despite exhibiting the best repair results, VitroFil LC was the only GIC that was influenced by all the acid challenges

Esthetic recovery of teeth presenting fluorotic enamel stains using enamel microabrasion and home-monitored dental bleaching.

This clinical report describes the enamel microabrasion technique for removing maxillary and mandibular hard fluorotic enamel stains followed by home-monitored home dental bleaching. The removal of fluorotic enamel stains utilized macroabrasion with a water-cooled, fine-tapered 3195 FF diamond bur followed microabrasion with the application of Prema Compound (Premier Dental Products Co, Norristown, PA, USA). Home-monitored dental bleaching was performed 14 days after enamel microabrasion using a 10% carbamide peroxide gel for 2 h/day. The wearing time of the acetate tray/dental bleaching was quantified by a microsensor from TheraMon microelectronic system (Sales Agency Gschladt, Hargelsberg, Austria) that was completely embedded in the acetate trays. The teeth were bleached effectively during 23 days. The mean wearing time of the acetate trays/dental bleaching product was 1.54 h/day, for the upper and lower arches. The patient reported satisfaction with the treatment. The association of enamel microabrasion and home dental bleaching was an excellent clinical treatment for teeth affected with enamel fluorosis.

Auxiliary UV light devices for removal of fluorescent resin residues after bracket debonding.

OBJECTIVE: The purpose of this clinical report was to describe the detection of fluorescent resin residue after orthodontic bracket debonding with two UV light devices and analyze the surface morphology of enamel after 1 year. CLINICAL CONSIDERATIONS: A 22-year-old woman had orthodontic brackets removed by a previous dentist; however, resin residue was left on the enamel of the maxillary teeth. After confirming the fluorescent property of the resin, different protocols were used for each half of the maxillary arch. The first method, a black light lens was attached to a light-curing device to detect resin fluorescence, followed by polishing with silicone rubber tips. The second method used a light emitting diode light system attached to and activated by a high-speed handpiece, followed by polishing with discs. Both methods were completed with diamond polishing paste applied with felt discs. Polyvinyl siloxane impressions were made initially, after residue removal, after finishing and after polishing for morphologic analysis. The results were evaluated with photographs and the scanning electron microscope images made of resin casts from the impressions. A follow-up was made after 1 year. CONCLUSIONS: Both methods yielded a satisfactory clinical outcome, with a smooth surface, acceptable surface gloss and minimal tooth wear. The use of a UV device that excites fluorescence is recommended for the controlled removal of resin residue on enamel. CLINICAL SIGNIFICANCE: The controlled removal of resin residue from enamel after orthodontic treatment is challenging but can be improved with auxiliary methods for detecting resin residues. This clinical report describes two types of devices that excite fluorescent resins in a more rapid and precise technique to guide the practitioner in the controlled removal of residual resin on teeth.

Dental bleaching on teeth submitted to enamel microabrasion 30 years ago-a case report of patients' compliance during bleaching treatment.

OBJECTIVES: The present dental bleaching case report describes a new method that precisely quantifies the daily wearing-times of the bleaching product by inserting a microsensor in the acetate custom tray. The bleaching efficacy was also discussed since the patient was previously submitted to enamel microabrasion. METHODS: The patient was submitted to enamel microabrasion in 1987, and bleaching treatment was performed in 2005. In 2017, re-bleaching was executed using 10% peroxide carbamide. The electronic microsensor, TheraMon (TheraMon® microelectronic system; Sales Agency Gschladt, Hargelsberg, Austria), was embedded in the labial region of the upper and lower acetate trays to evaluate the wearing-times of the acetate trays/bleaching product. The patient was instructed to wear the tray for 6 to 8 h/day while sleeping. After 24 days of bleaching treatment, the data obtained from the TheraMon electronic devices was collected and interpreted. RESULTS: The patient did not entirely follow the bleaching treatment as recommended, as there was no evidence of use of the upper and lower trays for some days; additionally, the bleaching product was used for shorter and longer periods than was instructed. CONCLUSIONS: The TheraMon microeletronic device precisely measured the wearing-times of the acetate tray/bleaching product during the bleaching treatment. Teeth submitted to enamel microabrasion presented with a healthy clinical appearance after 30 years. CLINICAL SIGNIFICANCE: Measuring the length and frequency of use of an acetate tray/bleaching product can be important to clinicians and patients for obtaining a controlled and adequate bleaching treatment.

Microscopic evaluation of rotatory and handle caries removal on glass ionomer cement/dentin interface

Aim: This study evaluated the interface between glass ionomer cement (GIC) and dentin using the conventional and atraumatic restorative treatment (ART) techniques for removal of decayed tissue. Materials and Methods: After preparation of the cavities by the conventional (Group I ­ GI) and ART (Group II ­ GII) techniques, the specimens were divided into 3 subgroups according to the GIC used (n=10). The conventional GIC KETAC FILL (3M/ESPE) was used in the groups GI-1 and GII-1, the conventional GIC VIDRION R (SS WHITE) in the groups GI-2 and GII-2, and the modified GIC FUJI II LC (GC Corporation) in the groups GI-3 and GII-3. For the microscopic analysis, the teeth were decalcified in a solution containing equal portions of 50% formic acid and 20% sodium citrate, dehydrated and submitted to paraffin baths. The samples were sectioned (6m in thickness), stained by the Brown and Brenn method, and evaluated in a light microscope. Results: The microscopic analysis revealed interaction between the material and dentin structure only with the FUJI II LC. In addition, the behavior was superior for the conventional technique in comparison to the ART technique. Conclusion: It was concluded that the technique used for carious dentin removal does not seem to be determinant for the bonding of ionomeric materials to the dental structure, except for the resin-modified GIC in which the formed hybrid layer was higher using the conventional technique

Two-Year Clinical Evaluation of a Nanofilled Etch-and-Rinse and a Self-Etch Adhesive System Containing MDPB and Fluoride in Non-carious Cervical Lesions.

OBJECTIVES: The aim of this clinical study was to evaluate the performance of restorations for non-carious cervical lesions performed with a two-step etch-and-rinse or with a two-step self-etch adhesive. MATERIALS AND METHODS: The teeth to be restored (15 patients, N = 90 restorations) were randomly assigned into 3 groups (n = 30), according to the adhesive system: group 1 (G1): Peak LC Bond; group 2 (G2): Clearfil Protect Bond; and group 3 (G3): prior selective acid etching of the enamel margins before bonding with Clearfil Protect Bond. The NCCLs were restored with Amelogen Plus composite resin. Two calibrated examiners evaluated the restorations using modified US Public Health Service criteria. The data of retention, marginal integrity, and marginal discoloration were analyzed using the Kruskal-Wallis and Wilcoxon tests. RESULTS: There were no significant differences in clinical performance among the groups for the variables: retention, marginal integrity, and marginal discoloration after 1 year and 2 years. The alpha rates after 2 years were: 93.3% for G1 and 96.7% for G2 and G3 for retention; 93.3%, 100%, and 90% for G1, G2, and G3 for marginal discoloration; 86.7%, 96.7%, and 90% for G1, G2, and G3 for marginal integrity, respectively. CONCLUSIONS: The adhesives presented similar clinical performance at the end of 2 years. Also, the prior etching with phosphoric acid did not significantly improve the clinical performance of self-etch adhesive.

Efficacy of auxiliary devices for removal of fluorescent residue after bracket debonding.

OBJECTIVE: To evaluate four protocols for removal of fluorescent materials after bracket debonding. MATERIALS AND METHODS: Resin removal from 40 bovine enamel surfaces was performed according to groups (n = 10): conventional (C), white LED (W), LED that evidenced fluorescence (F), and fluorescent lens (FL). The following analyses were performed: sample thickness, superficial area of resin residue, and areas of resin residue or worn enamel in depth. ANOVA and Tukey tests were used to analyze sample thickness (P ≤ .05). Area measurements were analyzed by Kruskal-Wallis and Dunn's tests (P ≤ .05). RESULTS: The FL group showed the highest reduction in enamel thickness. F group final thickness was similar to that of other groups. The largest superficial areas of resin residue were found for the C and W groups, while the FL group had the greatest removal of resin residue. The C group exhibited the largest area in depth of resin residue. The FL and F groups exhibited the most loss of enamel with the least amount of resin residue; in contrast, the C and W groups presented the fewest areas of worn enamel and the most areas of resin residue. CONCLUSION: Auxiliary devices were useful for removal of fluorescent residue after bracket debonding.

Tooth enamel properties and morphology after microabrasion: an in situ study.

AIM: This study evaluated the effect of saliva on enamel after microabrasion with different microabrasive compounds under in situ conditions. METHODS: Enamel/dentin blocks (16 mm2 ) from bovine incisors were divided into nine groups (n = 19): one control group (no treatment), four groups treated with microabrasion using 35% phosphoric acid (H3 PO4 ) + pumice, and the last four groups treated with microabrasion using 6.6% hydrochloric acid (HCl) + silica. The treated groups were subdivided according to the in situ regimen: without salivary exposure, 1 h, 24 h, or 7 days of saliva exposure. Surface microhardness (SMH) and cross-sectional microhardness (CSMH) were tested. Scanning electron microscopy (SEM) was used to evaluate enamel morphology. Microhardness data were tested by analysis of variance, and Tukey's and Dunnett's tests (α = 0.05). RESULTS: The SMH analysis revealed that all the microabrasion-treated groups presented significantly-reduced SMH values when compared to the control group (P < 0.05). Treatment with HCl + silica was more prone to the effect of saliva than H3 PO4 + pumice, even for CSMH analysis, once the superficial layers reached the same microhardness of that of the control group (P > 0.05). These results were confirmed by SEM, which demonstrated the mineral recovery effect over time. CONCLUSION: Saliva was effective in promoting the rehardening of enamel after microabrasion, mainly for the surfaces treated with HCl + silica.

The Effect of Hydrofluoric Acid Concentration and Heat on the Bonding to Lithium Disilicate Glass Ceramic.

The aim of this study was to evaluate the effects of hydrofluoric acid (HF) concentration and previous heat treatment (PHT) on the surface morphology and micro-shear bond strength (mSBS) of a lithium disilicate glass ceramic (EMX) to resin cement. One hundred four EMX specimens were randomly assigned to two groups (n=52) according to the HF concentration: 5% and 10%. A new random distribution was made according to the PHTs (n=13): control (no PHT); previously heated HF (70 °C); previously heated EMX surface (85 °C); the combination of heated HF + heated EMX surface. The etching time was set at 20 s. All EMX blocks were silanated and received a thin layer of an unfilled resin. Five resin cement cylinders were made on each EMX surface using Tygon tubes as matrices, and then stored for 24 h at 37 °C. One random etched EMX sample from each group was analyzed using field-emission scanning electron microscopy (FE-SEM). The data were subjected to two-way ANOVA and multiple comparisons were performed using the Tukey post hoc test (a=0.05). For the control groups, 5% HF showed statistically lower mSBS values when compared to 10% HF (p<0.05). PHT increased the mSBS values for 5% HF, yielding statistically similar results to non-PHT 10% HF (p<0.05). FE-SEM images showed increased glassy matrix removal when PHT was applied to HF 5%, but not to the same degree as for 10% HF. PHT has the potential to improve the bond strength of 5% HF concentration on lithium disilicate glass ceramic.

The Effect of Hydrofluoric Acid Concentration and Heat on the Bonding to Lithium Disilicate Glass Ceramic

Abstract The aim of this study was to evaluate the effects of hydrofluoric acid (HF) concentration and previous heat treatment (PHT) on the surface morphology and micro-shear bond strength (mSBS) of a lithium disilicate glass ceramic (EMX) to resin cement. One hundred four EMX specimens were randomly assigned to two groups (n=52) according to the HF concentration: 5% and 10%. A new random distribution was made according to the PHTs (n=13): control (no PHT); previously heated HF (70 °C); previously heated EMX surface (85 °C); the combination of heated HF + heated EMX surface. The etching time was set at 20 s. All EMX blocks were silanated and received a thin layer of an unfilled resin. Five resin cement cylinders were made on each EMX surface using Tygon tubes as matrices, and then stored for 24 h at 37 °C. One random etched EMX sample from each group was analyzed using field-emission scanning electron microscopy (FE-SEM). The data were subjected to two-way ANOVA and multiple comparisons were performed using the Tukey post hoc test (a=0.05). For the control groups, 5% HF showed statistically lower mSBS values when compared to 10% HF (p<0.05). PHT increased the mSBS values for 5% HF, yielding statistically similar results to non-PHT 10% HF (p<0.05). FE-SEM images showed increased glassy matrix removal when PHT was applied to HF 5%, but not to the same degree as for 10% HF. PHT has the potential to improve the bond strength of 5% HF concentration on lithium disilicate glass ceramic.

Resumo O objetivo deste estudo foi avaliar os efeitos das concentrações de ácido fluorídrico (AF) e do prévio tratamento térmico (PTT) na morfologia da superfície e resistência de união ao microcisalhamento (mRUM) de uma cerâmica vítrea de dissilicato de lítio (EMX) ao cimento resinoso. Cento e quatro espécimes de EMX foram aleatoriamente distribuídos em dois grupos (n=52) de acordo com a concentração do AF: 5% e 10%. Os espécimes foram novamente distribuídos de forma aleatória de acordo com o PTT (n=13): controle (sem PTT); AF previamente aquecido (70 °C); superfície do EMX previamente aquecida (85 °C); combinação entre AF e EMX aquecidos. O tempo de condicionamento foi fixado em 20 s. Todos os espécimes de EMX foram silanizados e receberam a aplicação de uma fina camada de um adesivo sem carga. Cinco cilindros de cimento resinoso foram confeccionados usando tubos Tygon como matrizes e então armazenados por 24 h a 37 °C. Uma amostra condicionada de cada grupo foi aleatoriamente selecionada e analisada em um microscópio eletrônico de varredura em emissão de campo (MEVEC). Os dados foram submetidos ao teste ANOVA de dois fatores e múltiplas comparações foram feitas pelo teste de Tukey (a=0.05). Para os grupos controle, AF 5% mostrou valor de mRUM estatisticamente menor do que AF 10% (p<0.05). PTT aumentou os valores de mRUM para o AF 5%, proporcionando resultados estatisticamente similares ao grupo AF 10% controle (p<0.05). MEVEC mostrou um aumento na remoção da matriz vítrea quando o PTT foi aplicado ao grupo AF 5%, no entanto esse efeito não foi visto no grupo AF 10%. O PTT tem o potencial de melhorar a resistência de união do AF 5% na cerâmica vítrea reforçada por disilicato de lítio.

Three-Year Clinical Evaluation of Class I Restorations in Posterior Teeth. Effects of Two Adhesive Systems.

This longitudinal study evaluated the clinical performance of 97 direct class I resin composite restorations after 3 years. The restorations were performed using 2 types of adhesive systems: (1) Adper™ Single Bond Plus (SB) (3M ESPE, 3mespe.com), which is a two-step etch-and-rinse system, and (2) Adper Scotchbond™ SE (SE) (3M ESPE), which is a two-step self-etching system. Two calibrated examiners evaluated the restorations using modified US Public Health Service criteria. The materials were applied following the manufacturer's instructions, and 15 patients received at least one of the two adhesive systems. The restorations were evaluated 7 days after placement (baseline) and again after 3 years. Statistical analysis was performed using a proportion t-test at a significance level of 5% (P < .05). At baseline, all restorations received an Alpha score for the variable marginal discoloration and marginal integrity. After 3 years, marginal discoloration received an Alpha score for 53.19% of the restorations performed with SB and 52.08% with SE. Marginal integrity was rated as Alpha for 65.96% and 68.75% of the restorations with SB and SE systems, respectively. The remaining restorations received Bravo scores for all variables. Eight restored teeth presented postoperative sensitivity at baseline (5 SB; 3 SE), but no sensitivity was found after 3 years. No secondary caries was verified. No statistically significant differences were observed between the teeth restored with the SB and SE systems for marginal discoloration (P = .7880) and marginal integrity (P = .8132) after 3 years. Direct class I resin composite restorations performed with a two-step etch-and-rinse and a two-step self-etching adhesive system demonstrated satisfactory clinical performance after 3 years.

Effect of Fluoride-Releasing Adhesive Systems on the Mechanical Properties of Eroded Dentin.

The aim of the study was to evaluate the effect of erosive pH cycling with solutions that simulate dental erosion on Martens hardness (HMV) and elastic modulus (Eit) of dentin restored with fluoride-releasing adhesive systems. Twenty-seven bovine dentin slabs were restored with three adhesive systems: Adper Single Bond 2 total-etch adhesive system, One Up Bond F and Clearfil SE Protect fluoride-containing self-etching adhesive systems. The restorations were made with Filtek Z250. The HMV and Eit values at distances of 10, 30, 50 and 70 µm from the interface were evaluated using a dynamic ultra microhardness tester before and after immersion in deionized water, citric acid and hydrochloric acid (n=9). Data were submitted to repeated-measures ANOVA and Fisher's PLSD tests (=0.05). After erosive cycling, HMV values of dentin decreased in all groups. For dentin restored with Adper Single Bond 2, the lowest values were found closer to the hybrid layer, while for One Up Bond F and Clearfil SE Protect, the values remained unaltered at all distances. For dentin restored with fluoride-releasing adhesive systems, a decrease in Eit was found, but after 30 µm this difference was not significant. The acid substances were able to alter HMV and Eit of the underlying dentin. For fluoride-releasing adhesives, the greater the distance from bonded interface, the lower the Eit values. The fluoride in One Up Bond F and Clearfil SE Protect was able to protect the underlying dentin closer to the materials. In this way, the fluoride from adhesive systems could have some positive effect in the early stages of erosive lesions.

Effect of Fluoride-Releasing Adhesive Systems on the Mechanical Properties of Eroded Dentin

Abstract The aim of the study was to evaluate the effect of erosive pH cycling with solutions that simulate dental erosion on Martens hardness (HMV) and elastic modulus (Eit) of dentin restored with fluoride-releasing adhesive systems. Twenty-seven bovine dentin slabs were restored with three adhesive systems: Adper Single Bond 2 total-etch adhesive system, One Up Bond F and Clearfil SE Protect fluoride-containing self-etching adhesive systems. The restorations were made with Filtek Z250. The HMV and Eit values at distances of 10, 30, 50 and 70 µm from the interface were evaluated using a dynamic ultra microhardness tester before and after immersion in deionized water, citric acid and hydrochloric acid (n=9). Data were submitted to repeated-measures ANOVA and Fisher's PLSD tests (=0.05). After erosive cycling, HMV values of dentin decreased in all groups. For dentin restored with Adper Single Bond 2, the lowest values were found closer to the hybrid layer, while for One Up Bond F and Clearfil SE Protect, the values remained unaltered at all distances. For dentin restored with fluoride-releasing adhesive systems, a decrease in Eit was found, but after 30 µm this difference was not significant. The acid substances were able to alter HMV and Eit of the underlying dentin. For fluoride-releasing adhesives, the greater the distance from bonded interface, the lower the Eit values. The fluoride in One Up Bond F and Clearfil SE Protect was able to protect the underlying dentin closer to the materials. In this way, the fluoride from adhesive systems could have some positive effect in the early stages of erosive lesions.

Resumo O objetivo deste estudo foi avaliar o efeito da ciclagem de pH erosiva com soluções que simulam a erosão dental, na dureza Martens (HMV) e módulo de elasticidade (Eit) da dentina restaurada com sistemas adesivos contendo fluoretos. Vinte e sete blocos de dentina foram restaurados com três sistemas adesivos: sistema adesivo de condicionamento total Adper Single Bond 2 e sistemas adesivos autocondicionantes contendo fluoreto One Up Bond F e Clearfil SE Protect. As restaurações foram realizadas com resina Filtek Z250. Os valores de HMV e Eit nas distâncias de 10, 30, 50 e 70µm da interface foram avaliadas em ultramicrodurômetro dinâmico antes e após a imersão em água deionizada, ácido cítrico e ácido clorídrico (n=9). Dados foram submetidos à ANOVA para medidas repetidas e Fisher PLSD (α=0,05). Após a ciclagem erosiva, os valores de HMV da dentina diminuíram em todos os grupos. Para a dentina restaurada com Adper Single Bond 2, os menores valores foram encontrados próximo a camada híbrida enquanto que, para os sistemas adesivos One Up Bond F e Clearfil SE Protect, os valores permaneceram inalterados em todas as distâncias. Para a dentina restaurada com os materiais que liberam fluoretos, uma redução nos valores de Eit foi encontrada, mas após 30µm essa diferença não foi mais significante. As substâncias ácidas foram capazes de alterar a HMV e o Eit da dentina subjacente. Para os adesivos que liberam fluoretos, quanto maior a distância da interface adesiva, menor os valores de Eit. O fluoreto presente no One Up Bond F e Clearfil SE Protect foi capaz de proteger a dentina subjacente próxima aos materiais. Dessa maneira, a presença do flúor em sistemas adesivos pode ter algum efeito positivo em estágios iniciais de lesões erosivas.

Surface effects after a combination of dental bleaching and enamel microabrasion: An in vitro and in situ study.

This study evaluated the effects of combining enamel microabrasion and dental bleaching on the physical properties of enamel, using in vitro and in situ conditions and evaluating surface roughness, enamel microhardness and scanning electron microscopy images. One hundred sound bovine teeth were sectioned and cut into discs and randomly divided into 10 study groups (n=10). The results were submitted to Analysis of Variance (ANOVA) for repeated measures, followed by the Tukey test, with significance at 5%. Enamel surface roughness was significantly influenced by microabrasion, regardless of being combined with dental bleaching, for both HS (Human Saliva) or AS (Artificial Saliva) condition. Enamel microhardness was significantly decreased in the groups in which enamel microabrasion was performed, regardless its combination with dental bleaching; although storage in HS reestablished the initial enamel microhardness. It was concluded that dental bleaching does not cause major damage to microabraided enamel, and that only human saliva recovered the initial enamel microhardness.

Clinical Comparison of At-Home and In-Office Dental Bleaching Procedures: A Randomized Trial of a Split-Mouth Design.

The objective of this split-mouth clinical study was to compare a combination of in-office and at-home dental bleaching with at-home bleaching alone. Two applications of in-office bleaching were performed, with one appointment per week, using 38% hydrogen peroxide. At-home bleaching was performed with or without in-office bleaching using 10% carbamide peroxide in a custom-made tray every night for 2 weeks. The factor studied was the bleaching technique on two levels: Technique 1 (in-office bleaching combined with home bleaching) and Technique 2 (home bleaching only). The response variables were color change, dental sensitivity, morphology, and surface roughness. The maxillary right and left hemiarches of the participants were submitted to in-office placebo treatment and in-office bleaching, respectively (Phase 1), and at-home bleaching (Phase 2) treatment was performed on both hemiarches, characterizing a split-mouth design. Enamel surface changes and roughness were analyzed with scanning electron microscopy and optical interferometry using epoxy replicas. No statistically significant differences were observed between the bleaching techniques for either the visual or the digital analyses. There was a significant difference in dental sensitivity when both dental bleaching techniques were used, with in-office bleaching producing the highest levels of dental sensitivity after the baseline. Microscopic analysis of the morphology and roughness of the enamel surface showed no significant changes between the bleaching techniques. The two techniques produced similar results in color change, and the combination technique produced the highest levels of sensitivity. Neither technique promoted changes in morphology or surface roughness of enamel.

Enamel microabrasion: An overview of clinical and scientific considerations.

Superficial stains and irregularities of the enamel are generally what prompt patients to seek dental intervention to improve their smile. These stains or defects may be due to hypoplasia, amelogenesis imperfecta, mineralized white spots, or fluorosis, for which enamel microabrasion is primarily indicated. Enamel microabrasion involves the use of acidic and abrasive agents, such as with 37% phosphoric acid and pumice or 6% hydrochloric acid and silica, applied to the altered enamel surface with mechanical pressure from a rubber cup coupled to a rotatory mandrel of a low-rotation micromotor. If necessary, this treatment can be safely combined with bleaching for better esthetic results. Recent studies show that microabrasion is a conservative treatment when the enamel wear is minimal and clinically imperceptible. The most important factor contributing to the success of enamel microabrasion is the depth of the defect, as deeper, opaque stains, such as those resulting from hypoplasia, cannot be resolved with microabrasion, and require a restorative approach. Surface enamel alterations that result from microabrasion, such as roughness and microhardness, are easily restored by saliva. Clinical studies support the efficacy and longevity of this safe and minimally invasive treatment. The present article presents the clinical and scientific aspects concerning the microabrasion technique, and discusses the indications for and effects of the treatment, including recent works describing microscopic and clinical evaluations.