Effect of medium or high concentrations of in-office dental bleaching gel on the human pulp response in the mandibular incisors.

Objectives: The present study evaluated the pulp response of human mandibular incisors subjected to in-office dental bleaching using gels with medium or high concentrations of hydrogen peroxide (HP). Materials and Methods: The following groups were compared: 35% HP (HP35; n = 5) or 20% HP (HP20; n = 4). In the control group (CONT; n = 2), no dental bleaching was performed. The color change (CC) was registered at baseline and after 2 days using the Vita Classical shade guide. Tooth sensitivity (TS) was also recorded for 2 days post-bleaching. The teeth were extracted 2 days after the clinical procedure and subjected to histological analysis. The CC and overall scores for histological evaluation were evaluated by the Kruskal-Wallis and Mann-Whitney tests. The percentage of patients with TS was evaluated by the Fisher exact test (α = 0.05). Results: The CC and TS of the HP35 group were significantly higher than those of the CONT group (p < 0.05) and the HP20 group showed an intermediate response, without significant differences from either the HP35 or CONT group (p > 0.05). In both experimental groups, the coronal pulp tissue exhibited partial necrosis associated with tertiary dentin deposition. Overall, the subjacent pulp tissue exhibited a mild inflammatory response. Conclusions: In-office bleaching therapies using bleaching gels with 20% or 35% HP caused similar pulp damage to the mandibular incisors, characterized by partial necrosis, tertiary dentin deposition, and mild inflammation.

Does simultaneous versus individual-arch at-home dental bleaching regimen influence patient satisfaction? A randomized clinical trial.

OBJECTIVE: Our randomized, parallel and single-blinded clinical trial evaluated patient level of discomfort during at-home bleaching testing the equivalence between two different protocols for the use of bleaching trays (simultaneous vs. single arch), as well as tooth sensitivity (TS), gingival irritation, (GI) and bleaching efficacy (BE). MATERIALS AND METHODS: We randomized 100 patients into: simultaneous (n = 50) and single arch (n = 50). At-home bleaching was performed with 10% hydrogen peroxide (HP) for 2 weeks for simultaneous group and 4 weeks for single arch group. We assessed patient level of discomfort using 9-item questionnaire. The TS and GI, as well as BE using spectrophotometer and color guide were assessed using the visual analog scale (0-10). Data from level of discomfort and BE were evaluated by Student's t test. The TS and GI were compared using the relative risk and confidence interval (α = 0.05). RESULTS: Only tray adaptation showed a significant effect after the second week (p < 0.002). There was equivalence between groups for level of discomfort (p < 0.01). We found no significant intergroup differences for the risk of TS or GI, nor for intensity. We observed no significant differences between them regarding bleaching efficacy (p > 0.21). CONCLUSIONS: A simultaneous-use protocol for customized at-home dental bleaching trays proved to be equivalent to using single arch for patient level of discomfort and bleaching efficacy, with no significant increase in adverse effects. CLINICAL SIGNIFICANCE: Clinicians may decide whether to use a simultaneous or single arch protocol for tray usage; however, bleaching was achieved more quickly when the trays were worn simultaneously.

Bleaching sensitivity with a desensitizing in-office bleaching gel: a randomized double-blind clinical trial.

OBJECTIVES: This split-mouth study assessed the bleaching sensitivity (risk and intensity) and color change after in-office bleaching using a desensitizing-containing (5% potassium nitrate) and a desensitizing-free 35% hydrogen peroxide gel. The null hypothesis was that there would be no differences between study groups regarding bleaching sensitivity. METHOD AND MATERIALS: Sixty patients participated in this split-mouth study. The subjects received desensitizing-containing hydrogen peroxide in half of the maxillary arch, and the other half received a desensitizing-free hydrogen peroxide, defined by random sequence, in two dental bleaching sessions. The bleaching sensitivity was evaluated during bleaching and from 1 h to 48 h after each bleaching session using a visual analog scale and numeric rating scale; the McNemar test, the Wilcoxon signed-rank test, and the Student-Newman-Keuls test were used for statistical analysis. The color was measured at baseline and 30 days post-bleaching, evaluated with paired t tests (P = .05). RESULTS: Statistically similar risks of bleaching sensitivity were observed (P = 1.000), but the intensity of bleaching sensitivity was lower (P < .011) on average by 1.32 visual analog scale units in the group bleached with the desensitizer-containing gel during up to 24 h assessment times. No statistical difference in color change was observed between groups (P > .321). CONCLUSION: The incorporation of 5% potassium nitrate into in-office bleaching gels does not reduce the risk of bleaching sensitivity, but it reduces its intensity slightly without jeopardizing color change.

PROPOSTA DE TERMO DE CONSENTIMENTO LIVRE E ESCLARECIDO PARA USO DE PROTETORES BUCAIS PERSONALIZADOS / Proposed of informed consent for use of personalized mouthguards

Durante a prática de esportes, especialmente considerando as modalidades de luta, a cavidade oral fica vulnerável aos eventos traumáticos decorrentes do contato entre os esportistas, o que pode comprometer o bom desenvolvimento da atividade e o próprio desempenho do atleta. A utilização de protetores bucais é uma medida fundamental para reduzir a ocorrência dessas injúrias e, principalmente as suas gravidades, favorecendo uma recuperação mais eficaz e rápida. Contudo, é obrigação ética do profissional e prerrogativa legal dos pacientes receber as informações relacionadas ao seu tratamento da forma mais completa possível, bem como certificar-se que os pacientes compreenderam estas questões. Neste trabalho, é apresentada uma proposta de um modelo de Termo de Consentimento Livre e Esclarecido para uso de protetores bucais personalizados, o qual aborda as questões pertinentes à confecção destes dispositivos. Este documento traz inúmeros benefícios para a especialidade, pois apresenta características como o fortalecimento do vínculo de confiança entre o dentista e o paciente atleta, a determinação de benefícios apropriados, riscos e encargos, a compreensão das vulnerabilidades entre as partes e a obtenção de permissões e aprovações. A confecção e o uso de protetores bucais apresentam especificidades importantes e estas devem estar esclarecidas para o paciente.

Tooth sensitivity with a desensitizing-containing at-home bleaching gel-a randomized triple-blind clinical trial.

OBJECTIVES: Desensitizing agents are usually included in the composition of bleaching agents to reduce bleaching-induced tooth sensitivity (TS). This randomized clinical trial (RCT) evaluated the risk and intensity of TS and color change after at-home bleaching with a desensitizing-containing (3% potassium nitrate and 0.2% sodium fluoride) and desensitizing-free 10% carbamide peroxide (CP) gel (Whiteness Perfect, FGM). METHODS: A triple-blind, within-person RCT was conducted on 60 caries-free adult patients. Each participant used the gel in a bleaching tray for 3 h daily for 21 days in both the upper and lower dental arches. The absolute risk and intensity of TS were assessed daily through the 0-10 VAS and NRS scale for 21 days. Color change was recorded using shade guides (Vita Classical and Vita Bleachedguide) and the Easyshade spectrophotometer at baseline, weekly and 30 days after the end of the bleaching. The risk and intensity of TS were evaluated by the McNemar and Wilcoxon Signed Rank tests, respectively. Color change (ΔSGU and ΔE) were evaluated by the Mann-Whitney test and a paired t-test, respectively (α = 0.05). RESULTS: No difference in the TS and color change was observed (p > 0.05). CONCLUSIONS: The incorporation of potassium nitrate and sodium fluoride in 10% carbamide peroxide at-home bleaching gel tested in this study did not reduce the TS and did not affect color change (RBR-4M6YR2).

Multiple Adhesive Layering Influence on Dentin Bonding and Permeability.

The aim was to evaluate the effect of the number of layers on the microtensile bond strength (µTBS), permeability and nanoleakage of an etch-and-rinse adhesive (Adper Single Bond 2). Different numbers of layers (1, 2 and 4) were applied on dentin susbstrate. Specimens were obtained and tested for µTBS. Stick-shaped samples were analysed by scanning electron microscope, to observe silver nitrate penetration. One-way ANOVA and Tukey tests were applied (α=0.05) for µTBS values. The fracture mode was evaluated under a stereomicroscope and a scanning electron microscope (SEM). Groups with two and four layers of bond showed higher µTBS to dentin and they also showed lower adhesive permeability than ONE layer. The silver nitrate uptake occurred in the hybrid layer in practically all groups. Fracture occurred predominantly at the mixed interface. The authors recommend the application of more than one layer of Adper Single Bond 2, because a single layer showed lower µTBS and higher permeability values.

Acid Etching with Modified Phosphoric Acid to Increase the Longevity of the Bonded Interface.

PURPOSE: To evaluate the effect of three phosphoric acids modified with chlorhexidine (CHX), benzalkonium chloride (BAC), or proanthocyanidins (PRO) and one conventional phosphoric acid (CON) on the immediate (24 h; IM) and 1-year composite-dentin microtensile bond strength (µTBS) and nanoleakage (NL), using an etch-and-rinse adhesive. MATERIALS AND METHODS: A flat dentin surface was exposed on 28 caries-free extracted molars, which were then randomly assigned to four groups (n = 7). After etching and rinsing with one phosphoric acid per group, the adhesive (Adper Single Bond 2) was applied on a moist dentin surface. Composite buildups (Filtek Z350) were constructed incrementally and bonded stick specimens (0.8 mm2) were prepared and submitted to the microtensile test (0.5 mm/min) immediately (24 h) or after 1 year of water storage. For nanoleakage, 2 bonded sticks from each tooth at each storage period were immersed in 50 wt% ammoniacal silver nitrate, polished, and analyzed by SEM in backscattered mode. Data were submitted to a two-way ANOVA and Tukey's test (α = 0.05). RESULTS: After 1 year, stable µTBS values were observed only for the modified phosphoric acids (CHX, BAC, and PRO). Also, NL was more evident in the CON group than in the CHX, BAC and PRO groups (p < 0.05) after 1-year water storage. CONCLUSIONS: Compared to the control, the phosphoric acid etchants which contained protease inhibitors (CHX, BAC and PA) promoted the stability of composite-dentin microtensile bond strength and showed less nanoleakage after 1 year of water storage. They represent an effective way of prolonging the stability of the composite-dentin bonds without creating an additional bonding step.

Five-year Effects of Chlorhexidine on the In Vitro Durability of Resin/Dentin Interfaces.

PURPOSE: To evaluate the effect of an acid containing 2% chlorhexidine (Ac/CHX) or a 2% CHX aqueous solution (Aq/CHX) on the immediate and 5-year bonding properties of resin/dentin interfaces produced by two adhesives. The presence of CHX in these interfaces was also evaluated under micro-Raman spectroscopy. MATERIALS AND METHODS: Forty-two molars were ground to expose a flat dentin surface. In the control group, the surfaces were etched with conventional phosphoric acid, and Prime&Bond NT (PB) and Adper Single Bond 2 (SB) were applied. In Ac/CHX, an acid containing 2% CHX was applied after adhesive application. In the Aq/CHX group, an aqueous solution of 2% CHX was applied for 60 s after etching. After placing the restoration, specimens were prepared and tested using the microtensile bond strength test (µTBS, 0.5 mm/min) immediately or after 5 years. For nanoleakage (NL), specimens at each period were immersed in silver nitrate solution and examined by EDX-SEM. In addition, specimens at each period underwent examination for CHX using micro-Raman spectroscopy. Data were submitted to appropriate statistical analysis (a=0.05). RESULTS: After 5 years, NL was more pronounced in the control than in the Ac/CHX or Aq/CHX (p<0.001). Significant reductions in the µTBS were observed for all groups; however, they were more pronounced for the control (p<0.001). CHX was still present in the hybrid layers Ac/CHX or Aq/CHX groups after 5 years. CONCLUSION: The use of a 2% chlorhexidine-containing acid or the application of an aqueous CHX primer may increase the long-term stability of resin/dentin interfaces.

Response of human pulps to different in-office bleaching techniques: preliminary findings.

This study evaluated a whitening effect and the likely side effect (tooth sensitivity and pulp response) of human teeth subjected to different in-office bleaching (IOB) techniques and materials, mainly the presence of calcium in the IOB materials. A calcium-free (CF) and a calcium-containing (CC) 35% hydrogen peroxide (HP) gels were evaluated. The CF was refreshed every 15 minutes, three times (CF 3-15) or in a single 45-min application (CF 1-45) at one bleaching appointment. The CC was used only in a single 45-min application (CC 1-45). Each technique was applied in 5 mandibular incisors scheduled for extraction for different patients. In control group, no tooth bleaching was performed. The tooth colour (TC) and tooth sensitivity (TS) were recorded at baseline and after IOB. The teeth were extracted 2 days after the application of IOB and subjected to histological analysis. The data was submitted to appropriate statistical analysis (α=0.05). The changes of TC were similar between groups and statistically different from the control (p<0.05). However, TS of groups bleached with CF was statistically higher than that recorded for CC and the control (p<0.05). In CF 3-15 and CF 1-45 groups, the coronal pulp tissue exhibited partial necrosis associated with tertiary dentin deposition. In CC 1-45 group smaller area of necrosis occurred only in three bleached teeth in which tertiary dentin deposition was observed. The calcium-containing 35%HP gel could be preferable for in-office bleaching because it caused less tooth sensibility and pulp damage.

Response of Human Pulps to Different In-Office Bleaching Techniques: Preliminary Findings

This study evaluated a whitening effect and the likely side effect (tooth sensitivity and pulp response) of human teeth subjected to different in-office bleaching (IOB) techniques and materials, mainly the presence of calcium in the IOB materials. A calcium-free (CF) and a calcium-containing (CC) 35% hydrogen peroxide (HP) gels were evaluated. The CF was refreshed every 15 minutes, three times (CF 3-15) or in a single 45-min application (CF 1-45) at one bleaching appointment. The CC was used only in a single 45-min application (CC 1-45). Each technique was applied in 5 mandibular incisors scheduled for extraction for different patients. In control group, no tooth bleaching was performed. The tooth colour (TC) and tooth sensitivity (TS) were recorded at baseline and after IOB. The teeth were extracted 2 days after the application of IOB and subjected to histological analysis. The data was submitted to appropriate statistical analysis (α=0.05). The changes of TC were similar between groups and statistically different from the control (p<0.05). However, TS of groups bleached with CF was statistically higher than that recorded for CC and the control (p<0.05). In CF 3-15 and CF 1-45 groups, the coronal pulp tissue exhibited partial necrosis associated with tertiary dentin deposition. In CC 1-45 group smaller area of necrosis occurred only in three bleached teeth in which tertiary dentin deposition was observed. The calcium-containing 35%HP gel could be preferable for in-office bleaching because it caused less tooth sensibility and pulp damage.

O objetivo do estudo foi avaliar o efeito clareador e seus efeitos adversos (sensibilidade e resposta pulpar) de dentes humanos submetidos a diferentes técnicas e materiais para o clareamento em consultório (CLCO), principalmente a presença de cálcio nos materiais para CLCO. Um agente clareador a base de peróxido de hidrogênio (PH) a 35% sem cálcio (SC) e com cálcio (CC) foram avaliados. O agente clareador SC foi usado em duas técnicas de aplicação: o gel clareador foi reaplicado a cada 15 minutos, três vezes (SC 3-15) ou 1 x 45-min por aplicação (SC 1-45) em uma sessão clínica. O agente clareador CC foi usado apenas em 1 x 45-min por aplicação (CC 1-45). Cada técnica foi aplicada em 5 incisivos inferiores indicados para extração de pacientes diferentes. No grupo controle, o clareamento não foi realizado. O efeito clareador (EC) e a sensibilidade dental (SD) foram registrados inicialmente e após o CLCO. Os dentes foram extraídos após 2 dias da aplicação do CLCO e foram submetidos ao análise histológica. Os dados foram submetidos a análise estatística apropriada (α=0.05). As mudanças foram semelhantes entre os grupos e significativamente diferentes do controle (p<0.05). Entretanto, a SD nos grupos clareados com SC foi estatisticamente maior do que a registrada nos grupos CC e do grupo controle (p<0.05). Nos grupos SC 3-15 e SC CF 1-45, o tecido pulpar da região coronária exibia necrose parcial associada a deposição de dentina terciária. No grupo CC 1-45, pequenas áreas de necrose ocorreram somente em 3 dentes clareados, nos quais deposição de dentina terciária também foi observada. O gel CC de HP a 35%HP gel poderia ser preferível para a realização de CLCO devido ao fato de causar menos danos ao tecido pulpar.

Mechanical properties and modeling of drug release from chlorhexidine-containing etch-and-rinse adhesives.

OBJECTIVES: To evaluate the effects of chlorhexidine (CHX) addition in different concentrations into simplified etch-and-rinse adhesives on the ultimate tensile strength (UTS), water sorption (WS), solubility (SO) and the rate of CHX release over time. METHODS: We added CHX diacetate to Ambar [AM] (FGM) and XP Bond [XP] (Dentsply) in concentrations of 0, 0.01, 0.05, 0.1 and 0.2 wt%. For UTS (n=10 for each group), adhesive specimens were constructed in an hourglass shape metallic matrix with cross-sectional area of 0.8 mm(2). Half of specimens were tested after 24 h and the other half after 28 days of water storage in tension of 0.5 mm/min. For WS and SO (n=10 for each group), adhesive discs (5.8 mm×1.0 mm) were prepared into a mold. After desiccation, we weighed and stored the cured adhesive specimens in distilled water for evaluation of the WS, SO and the cumulative release of CHX over a 28-day period. For CHX release (n=10 for each group), spectrophotometric measurements of storage solution were performed to examine the release kinetics of CHX. We subjected data from each test to ANOVA and Tukey' test (α=0.05). RESULTS: XP Bond adhesive showed significantly more WS and SO and lower UTS than Ambar. In general, the addition of CHX did not alter WS, SO and UTS of the adhesives. XP showed a higher CHX release than AM (p<0.05) in all concentrations and the final amount of CHX release was directly proportional to the initial CHX concentration added to the adhesives. After 28 days of water storage, approximately 20% of CHX was released from XP and 8.0-12.0% from AM. CONCLUSIONS: Addition of CHX to commercial adhesive is a feasible method to provide a controlled release of CHX over time without jeopardizing WS, SO and UTS of the adhesives. SIGNIFICANCE: Manufacturers should consider adding CHX to commercial adhesives to provide a controlled release of CHX over time.

Effects of chlorhexidine-containing adhesives on the durability of resin-dentine interfaces.

OBJECTIVES: This study evaluated the effect of addition of diacetate CHX in different concentrations into two simplified etch-and-rinse (ER) adhesive systems (XP Bond [XP] and Ambar {AM}) on the ultimate tensile strength (UTS), degree of conversion (DC), 60-day cumulative water sorption (WS), solubility (SO) and CHX release (CR) as well as the immediate (IM) and 1-year (1Y) resin-dentine bond strength (µTBS) and nanoleakage (NL). METHODS: Ten experimental adhesive systems were formulated according to the addition of CHX diacetate (0 [control], 0.01, 0.05, 0.1 and 0.2%) in the two ER. For UTS and DC, specimens were constructed and tested after 24h. For WS, SO and CR, after specimens build-up, they were stored in water and the properties measured after 60 days. The occlusal enamel of fifty molars was removed and the adhesives were applied in dentine surface after 37% phosphoric acid etching. After composite resin build-ups, specimens were longitudinally sectioned to obtain resin-dentine bonded sticks (0.8mm(2)). Specimens were tested in tension at 0.5mm/min in the IM or 1Y. For NL, 2 bonded sticks from each tooth were prepared and analyzed under SEM. The data were submitted to appropriate statistical analysis (α=0.05). RESULTS: The addition of CHX did not influence UTS, DC, WS and SO (p<0.05). Higher CR was observed in adhesives with higher concentration of CHX (p<0.05). After 1Y, significant reductions of µTBS and increases of NL were observed in the control groups (p<0.05). Reductions of µTBS and increase of NL over time were not observed (AM) for CHX-containing adhesives or it was less pronounced than the control (XP) regardless of the CHX concentration. CONCLUSIONS: The addition of CHX diacetate in concentrations until 0.2% in the simplified ER adhesive systems may be an alternative to increase the long-term stability of resin-dentine interfaces, without jeopardizing the adhesives' mechanical properties evaluated.

Effects of diphenyliodonium salt addition on the adhesive and mechanical properties of an experimental adhesive.

OBJECTIVES: The aim of this study was to assess the microtensile bond strength (µTBS), nanoleakage (NL), nano-hardness (NH) and Young's modulus (YM) of resin-dentine bonding components formed by an experimental adhesive system with or without inclusion of diphenyliodonium salt (DPIH) in the camphorquinone-amine (CQ) system. METHODS: On 12 human molars, a flat superficial dentine surface was exposed by wet abrasion. A model simplified adhesive system was formulated (40 wt.% UDMA/MDP, 30 wt.% HEMA and 30 wt.% ethanol). Two initiator systems were investigated: 0.5 mol% CQ+1.0 mol% EDMAB and 0.5 mol% CQ+1.0 mol% EDMAB+0.2 mol% DPIH. Each adhesive was applied and light-cured (10s; 600 mW/cm(2)). Composite build-ups were constructed incrementally and resin-dentine specimens (0.8mm(2)) were prepared. For NL, 3 bonded sticks from each tooth were coated with nail varnish, placed in the silver nitrate, polished down with SiC papers and analysed by EDX-SEM. NH and YM were performed on the hybrid layer in 2 bonded sticks from each teeth. The remaining bonded sticks were tested on µTBS (0.5mm/min). The data from each test were submitted to a Student t-test (α=0.05). RESULTS: No significant difference was found for µTBS between groups (p>0.05). Significant lower NL and higher NH and YM were found in the hybrid layer and adhesive layer produced with the iodinium salt-containing adhesive (p<0.05). CONCLUSIONS: The inclusion of the DPIH to the traditional CQ is a good strategy to improve the adhesive and mechanical properties of a simplified etch-and-rinse adhesive system.

The role of dentin moisture in the degradation of resin-dentin interfaces under clinical and laboratory conditions.

BACKGROUND: The authors conducted a study to evaluate the influence of dentin moisture on the degradation of the resin-dentin interface in primary teeth under clinical and laboratory conditions. METHODS: The authors prepared 40 Class I restorations (five teeth per group) by using a cylindrical diamond bur, leaving a flat dentin surface on the pulpal floor. They vigorously rubbed two coats of a simplified etch-and-rinse adhesive on either dry or wet demineralized dentin under clinical or laboratory conditions. After performing restorative procedures, the authors extracted teeth prepared under clinical conditions after 20 minutes (immediately) or the teeth exfoliated after six months. The authors also tested the teeth prepared under laboratory conditions immediately or after six months of being stored in water. They sectioned the teeth to obtain resin-dentin bonded specimens for microtensile testing and for silver nitrate uptake (SNU) under scanning electron microscopy. They performed a three-way analysis of variance and Tukey test (α = .05) on the SNU bond strength data. RESULTS: Statistically higher bond strength values (megapascals [standard deviation]) were observed when bonding was performed under laboratory conditions (clinical = 25.2 [3.6] MPa versus laboratory = 28.5 [4.4] MPa; P < .05). Degradation occurred only in the wet dentin groups under both experimental conditions (immediately = 31.3 [4.5] MPa versus after six months = 21.3 [2.1] MPa; P < .05). SNU occurred in all groups and was statistically higher after six months of clinical function or water storage (immediately = 13.9 [4.9 SD] percent versus after six months = 34.1 [4.5 SD] percent; P < .05). CONCLUSIONS: The bonding of adhesives to dry demineralized dentin produces adhesive interfaces that are more resistant to degradation regardless of the bonding condition. CLINICAL IMPLICATIONS: Resin-dentin bond strengths produced under laboratory conditions in primary teeth may be higher than those obtained under clinical circumstances, although both conditions (clinical and laboratory) seemed to yield similar results. Bonding to dry demineralized primary tooth dentin produced resin-dentin interfaces that were more resistant to degradation.

Effect of tetracycline on the bond performance of etch-and-rinse adhesives to dentin.

This study evaluated the effect of modified tetracycline on the resin-dentin bond strength (µTBS), silver nitrate uptake (SNU) and solution homogeneity (SH) of two adhesives. Dentin surfaces were treated with phosphoric acid, rinsed off and either rewetted with water (control group - CO), 2% minocycline (MI), 2% doxycyline (DO) or 2% chlorhexidine (CH). Adhesive systems (Adper Single Bond 2 and Prime Bond NT) and composite were applied and light-polymerized. Specimens were sectioned to obtain bonded sticks (0.8 mm²) to test under tension at 0.5 mm/min. For SNU, specimens were immersed in silver nitrate and analyzed by EDX-SEM. SH was qualitatively analyzed after mixing the adhesives with different solvent-based solutions containing MI, DO and CH. Lower µTBS values were observed in the DO group compared with MI and CH (p = 0.01). Lower SNU was observed for MI and CH. The lowest µTBS for both adhesives was observed for the DO group (p = 0.01). Signs of phase separation were observed for DO with both adhesives. MI or CH used as rewetting solutions after acid etching did not affect the µTBS and hybrid layer quality.

Clinical versus laboratory adhesive performance to wet and dry demineralized primary dentin.

PURPOSE: To evaluate the influence of dentin moisture on bond strengths of an etch-and-rinse bonding agent to primary dentin clinically and in the laboratory. METHODS: The sample consisted of two groups of 20 caries-free primary second molars: molars in exfoliation period (clinical group) and extracted molars (laboratory group). Class I cavities were prepared in all specimens leaving a flat dentin surface on the pulpal floor. A two-step etch-and-rinse adhesive was vigorously rubbed on either dry (n = 5) or wet demineralized dentin (n = 5) under clinical or laboratory conditions. After restorative procedures, the teeth from the clinical group were extracted after 20 minutes. All samples were processed and underwent microtensile bond strength test and silver nitrate uptake evaluation under scanning electron microscopy. RESULTS: Statistically higher bond strength values were observed when the bonding was performed under laboratory conditions and on a wet demineralized dentin. Most of the failures were adhesive and mixed irrespective of the experimental condition. Silver nitrate uptake occurred in all groups irrespective of the experimental condition. Resin-dentin bond strengths produced in the laboratory in primary teeth may overestimate those produced under clinical circumstances.

The effect of 6-month water storage on the bond strength of self-etch adhesives bonded to dentin.

PURPOSE: To evaluate the microtensile bond strengths (microTBS) of 1-step vs. 2-step self-etch systems to dentin after 24 hours and after 6 months of water storage. METHODS: Resin composite buildups were bonded to occlusal dentin of third molars using the following adhesives: Xeno IV (XE, Dentsply), G-Bond (GB, GC Inc), Clearfil S3 Bond (CS3, Kuraray); Adper Prompt L-Pop (AD, 3M ESPE); Go (GO, SDI), All Bond SE (ABSE 1-step or ABSE 2-step, Bisco) and Clearfil SE Bond (CSE, Kuraray). The bonded sticks (cross-sectioned area of 0.8-0.9 mm2) originated from the same teeth were randomly divided to be tested after 24 hours or after 6 months of water storage. The data was submitted to two-way repeated measures ANOVA and Tukey's test with and without the inclusion of premature failures (PF) (alpha = 0.05). RESULTS: The inclusion of PF resulted in different statistically significant means for CS3, CSE and AD (P<0.05). Only the ABSE2 showed stable bonds after 6 months of water storage (P>0.05).

Effect of tetracycline on the bond performance of etch-and-rinse adhesives to dentin

This study evaluated the effect of modified tetracycline on the resin-dentin bond strength (µTBS), silver nitrate uptake (SNU) and solution homogeneity (SH) of two adhesives. Dentin surfaces were treated with phosphoric acid, rinsed off and either rewetted with water (control group - CO), 2 percent minocycline (MI), 2 percent doxycyline (DO) or 2 percent chlorhexidine (CH). Adhesive systems (Adper Single Bond 2 and Prime Bond NT) and composite were applied and light-polymerized. Specimens were sectioned to obtain bonded sticks (0.8 mm²) to test under tension at 0.5 mm/min. For SNU, specimens were immersed in silver nitrate and analyzed by EDX-SEM. SH was qualitatively analyzed after mixing the adhesives with different solvent-based solutions containing MI, DO and CH. Lower µTBS values were observed in the DO group compared with MI and CH (p = 0.01). Lower SNU was observed for MI and CH. The lowest µTBS for both adhesives was observed for the DO group (p = 0.01). Signs of phase separation were observed for DO with both adhesives. MI or CH used as rewetting solutions after acid etching did not affect the µTBS and hybrid layer quality.

Avaliação clínica de uma resina autoadesiva para a colagem de bráquetes ortodônticos / Clinical evaluation of a self-adhesive material to bonded orthodontic brackets

O objetivo desse estudo foi avaliar o tempo de aplicação e a taxa de retençãoapós seis meses de dois sistemas ortodônticos de colagem: um convencional (TransbondXT, 3M Unitek) e uma resina autoadesiva (Orthocem, FGM). Um operador, usando a técnicaStraight-Wire, colou 955 bráquetes metálicos em 60 pacientes com idade entre 12 e 39 anos.Os bráquetes foram colados de acordo com as instruções dos fabricantes e foram avaliadosmensalmente. O modo de fratura foi visualmente classificado como: resina/esmalte, resina/bráquete, fratura coesiva e mista. A taxa de retenção dos bráquetes foi estimada através decurvas de sobrevivência (Kaplan-Meier e teste Log-rank, p < 0,05). A taxa de retenção em seismeses do Transbond XT foi de 93,0% e do Orthocem, 92,7%. Nenhuma diferença estatística nastaxas de retenção foi observada entre os materiais (p > 0,05). A maioria das falhas foi mista. OOrthocem permitiu a colagem em tempo menor em comparação ao Transbond XT (p <0,05).Esses achados indicam que a resina autoadesiva para colagem de bráquetes Orthocem podeser usada satisfatoriamente para colagem de acessórios ortodônticos.

The aim of this study was to evaluate, time to bonding and the retention rate overa 6-month period of two orthodontic adhesives (Transbond XT, 3M Unitek and Ortnocem, FGM).One operator, using the straight-wire technique, bonded 955 metallic brackets to the teeth of 60patients (age range 12 - 39 years) in a way that patients acted as self-control. The brackets werebonded following the 'manufacturers' instructions. The failure modes were visually classified into:adhesive-enamel, adhesive-bracket, cohesive failure and mixed. The survival rates of the bracketswere estimated by survival curve (Kaplan-Meier and Log-rank test (p < 0.05). The retention rateat six months, Transbond XT and Orthocem was 93.0% and 92.7% respectively. No significantdifferences in the survival rate were observed between the materiais (p > 0.05). Most of thefailures were mixed and at the adhesive - enamel interface. Orthocem allowed brackett bondedin lower time than Transbond XT (p < 0.05). These findings indicate that simplified Orthocemfor orthodontic bonding can be safely used.

Effect of 3-year water storage on the performance of one-step self-etch adhesives applied actively on dentine.

OBJECTIVES: To evaluate the effect of the application method on the immediate and 3-year resin-dentine bond strength (µTBS) and nanoleakage (NL) for 3 one-step self-etch adhesives (Adper Prompt L-Pop; Clearfil S(3) Bond and Xeno III). METHODS: The occlusal enamel of 42 human molars were removed to expose a flat dentine surface. The adhesives were applied under inactive or active application. After light-curing (600mW/cm(2) for 10s), composite buildups were constructed incrementally and sectioned to obtain bonded sticks (0.8mm(2)) to be tested in tension immediately or after 3 years of water storage of water storage. For NL, 2 bonded sticks from each tooth at each time were coated with nail varnish, placed in silver nitrate and polished down with SiC paper. The µTBS data was submitted to a two-way repetead mesures ANOVA and Tukey's test for each adhesive (α=0.05). RESULTS: The active application showed higher immediate and 3-year µTBS than the inactive application (p<0.05). An increase in the silver nitrate deposition was seen for all conditions after 3 years; however this was more pronounced for all materials under inactive application (p<0.05). CONCLUSIONS: The active application improves the immediate bonding performance of the adhesive systems. Reductions of the bond strength were observed for all materials after 3 years, however reduced degradation rate was observed when the materials are applied actively in dentine.