Evaluation of enamel roughness after the removal of brackets bonded with different materials: In vivo study

Abstract The aims of this in vivo study were to evaluate the effect of bonding with resin-modified glass ionomer cement (RMGIC) and to assess enamel surface roughness before and after the removal of brackets bonded with composite or RMGIC from the maxillary central incisors. Fifteen orthodontic patients were selected for the study. For each patient, the teeth were rinsed and dried, and brackets were bonded with composite (Transbond XT) and RMGIC (Vitremer Core Buildup/Restorative). At the conclusion of orthodontic treatment, their brackets were removed. Dental replicas were made of epoxy resin in initial conditions (before bonded) and after polishing with an aluminum oxide disc system. Adhesive remnant index (ARI) and surface roughness was measured on the dental replicas and data were evaluated statistically by Mann-Whitney and paired t-test, respectively. No bracket debonding occurred during patients' treatment periods. It was verified that the ARI values of the two maxillary central incisors were similar (p = 0.665). For both bonding materials, the ARI value of 3 was predominant. After polishing, surface roughness was similar in the composite and RMGIC groups (0.245 μm and 0.248 μm, respectively; p = 0.07). In both groups, enamel surface roughness values were significantly lower after polishing compared with the initial condition (p < 0.001). RMGIC promoted efficiency in cementing brackets without fail during treatment; the choice of composite or RMGIC materials was not a factor that influenced the roughness of the enamel surface, however, polishing led to smoother surfaces than those found at the beginning of the treatment.

Resumo Os objetivos deste estudo in vivo foram avaliar o efeito da colagem com cimento de ionômero de vidro modificado por resina (CIVMR) e a rugosidade da superfície do esmalte antes e após a remoção dos braquetes colados com compósito ou CIVMR em incisivos centrais superiores. Quinze pacientes ortodônticos foram selecionados para o estudo. Para cada paciente, os dentes foram lavados e secos, e os braquetes colados com compósito (Transbond XT) e CIVMR (Vitremer Core Buildup / Restorative). Ao término do tratamento ortodôntico, os braquetes foram removidos. As réplicas dentais foram confeccionadas em resina epóxica nas condições iniciais (antes da colagem) e após o polimento com sistema de discos de óxido de alumínio. O índice de remanescente adesivo (IRA) e a rugosidade da superfície foram mensurados nas réplicas dentais e os dados foram avaliados estatisticamente por Mann-Whitney e teste t pareado, respectivamente. Não ocorreu descolagem de braquetes durante os períodos de tratamento dos pacientes. Verificou-se que os valores do IRA dos dois incisivos centrais superiores foram semelhantes (p = 0,665). Para ambos os materiais de colagem, o valor de IRA predominante foi 3. Após o polimento, a rugosidade da superfície do esmalte foi semelhante nos grupos compósito (0,245 μm) e CIVMR (0,248 μm) (p = 0,07). Em ambos os grupos, os valores de rugosidade da superfície do esmalte foram significativamente menores após o polimento em comparação com a condição inicial (p <0,001). CIVMR promoveu eficiência na colagem de braquetes sem falhas durante o tratamento; a escolha dos materiais compósito ou CIVMR não foi um fator que influenciou na rugosidade da superfície do esmalte, porém, o polimento levou a superfícies mais lisas do que as encontradas no início do tratamento.

Bonding performance of self-etch adhesives to enamel bleached with different peroxide concentrations

Abstract The aim of this study was to evaluate the micro-shear bond strength (µSBS) of one and two steps self-etch adhesive systems after enamel bleaching with photo-activated bleaching systems of different hydrogen peroxide (HP) concentration. Occlusal enamel of forty intact human molars were flattened and assigned into four groups. GI Unbleached, GII, GIII, and GIV were bleached with Pyrenees (3.5% HP), GC TiON (20% HP), and Hi-Lite (35% HP) respectively. Enamel treatment with one and two steps self-etch adhesives (Clearfil S3 Bond- S3, and Clearfil SE Bond-SE) then micro-tubes were fixed on enamel and filled with AP-X composite (n=5). Bond was tested with the universal testing machine. Data were analyzed using two-way ANOVA and Tukey's tests at 5 % level of significance. The µSBS was significantly different between adhesives (F=154.46; p<0.05) and bleaching systems (F=77.33; p<0.05) with significant interaction. Specimens bonded with S3 shows a significantly lower μSBS than those bonded with SE (p<0.05) in all groups. For both adhesives the bleached groups demonstrate lower µSBS than unbleached except specimens bleached with Pyrenees and bonded with SE (p>0.05). A significant difference was observed between groups of the bleaching systems (p<0.05). Different peroxide concentrations photo-activated bleaching systems adversely affect μSBS of one and two steps self-etch adhesives. Low concentration system (Pyrenees) does not influence the bond strength of two steps adhesive.

Resumo O objetivo deste estudo foi avaliar a resistência ao cisalhamento (µSBS) de sistemas auto-adesivos de um e dois passos após clareamento do esmalte com sistemas de clareamento foto-ativados de diferentes concentrações de peróxido de hidrogênio (HP). O esmalte oclusal de quarenta molares humanos intactos foi aplainado e atribuído em quatro grupos. GI Unbleached, GII, GIII, e GIV foram branqueados com Pyrenees (3,5% HP), GC TiON (20% HP), e Hi-Lite (35% HP) respectivamente. Tratamento de esmalte com adesivos de um e dois passos auto-adesivos (Clearfil S3 Bond- S3, e Clearfil SE Bond-SE), depois os microtubos foram fixados no esmalte e preenchidos com composto AP-X (n=5). A resistência ao cisalhamento foi testada com a máquina universal de testes. Os dados foram analisados usando os testes de ANOVA e Tukey de duas vias a um nível de 5% de significância. O µSBS foi significativamente diferente entre adesivos (F=154,46; p<0,05) e sistemas de clareadores (F=77,33; p<0,05) com interação significativa. Os espécimes colados com S3 mostram um μSBS significativamente inferior aos colados com SE (p<0,05) em todos os grupos. Para ambos os adesivos, os grupos clareados demonstram µSBS inferiores aos não clareados exceto os espécimes clareados com Pyrenees e colados com SE (p>0,05). Foi observada uma diferença significativa entre os grupos dos sistemas de clareamento (p<0,05). Diferentes concentrações de peróxidos foto-ativados nos sistemas de clareamento afetam negativamente μSBS dos adesivos de uma e duas etapas de auto-colagem. O sistema de baixa concentração (Pyrenees) não influenciou a resistência ao cisalhamento do adesivo de duas etapas.

Durabilidade da união à dentina e liberação de cálcio promovidas por sistemas adesivos experimentais com adição de hidróxido de cálcio / Durability of the bond to dentin and calcium release promoted by experimental adhesive systems with the addition of calcium hydroxide

Objetivo: Este estudo investigou a liberação de cálcio (CaR) e estabilidade de adesão à dentina em longo prazo (DBS) de sistemas adesivos autocondicionantes experimentais contendo hidróxido de cálcio. Metodologia: Quatro sistemas adesivos foram formulados incluindo monômeros UDMA, HEMA, GDMA-P, TPO e difenil iodônio como sistema fotoiniciador, e etanol / água como solvente com diferentes frações de massa de hidróxido de cálcio: 0% (controle), 1%, 2% e 4%. O DBS foi medido pelo método de microtração de resistência de união em máquina de ensaio de microtração. O terço médio da dentina de 24 terceiros molares humanos (n = 6) foi usado para unir os sistemas adesivos a uma resina composta. Amostras em forma de palitos (1 mm2 ) foram obtidas após 24 horas de imersão em água destilada e testadas imediatamente e após 12 meses de armazenamento em água. Os dados foram avaliados estatisticamente por meio de ANOVA de dois fatores e pós-teste de Tukey (p <0,05). O CaR foi avaliado por meio de espectrofotômetro. Os espécimes em discos (6,0 mm de diâmetro x 0,3 mm de espessura) foram produzidos (n = 4) e imersos em água destilada. A concentração de cálcio foi medida após 3 h até 168 h. Resultados: Para DBS, os sistemas adesivos contendo 0%, 1% e 4% de hidróxido de cálcio apresentaram médias estatisticamente semelhantes entre os pontos de tempo imediato (24h) e 12 meses. O sistema adesivo contendo 2% de hidróxido de cálcio apresentou resistência de união estatisticamente maior em 12 meses (p = 0,001). Nenhum material liberou cálcio até 168 h após a fotoativação. Conclusão: A inclusão de hidróxido de cálcio a 2% resultou na melhora da durabilidade de união à dentina a longo prazo. No entanto, a inclusão de hidróxido de cálcio aos sistemas adesivos experimentais testados não foi capaz de liberar cálcio (AU).

Objective: This study investigated the calcium release (CaR) and long-term dentin bonding stability (DBS) of experimental self-etching adhesive systems containing calcium hydroxide. Methodology: Four adhesive systems were formulated including UDMA, HEMA, GDMA-P, TPO and diphenyl iodonium monomers as photoinitiator system, and ethanol/water as solvent with different mass fractions of calcium hydroxide: 0% (control), 1%, 2% and 4%. DBS was measured by the microtensile bond strength method in a microtensile testing machine. The middle third of dentin from 24 human third molars (n = 6) was used to bond the adhesive systems to a composite resin. Stick-shaped samples (1 mm2) were obtained after 24 hours of immersion in distilled water and tested immediately and after 12 months of storage in water. Data were statistically evaluated using two-way ANOVA and Tukey's post-test (p < 0.05). CaR was evaluated using a spectrophotometer. Disc specimens (6.0 mm in diameter x 0.3 mm thick) were produced (n = 4) and immersed in distilled water. Calcium concentration was measured after 3 h to 168 h. Results: For DBS, adhesive systems containing 0%, 1% and 4% calcium hydroxide had statistically similar means between the immediate time points (24h) and 12 months. The adhesive system containing 2% calcium hydroxide had a statistically higher bond strength in 12 months (p = 0.001). No material released calcium up to 168 h after photoactivation. Conclusion: The inclusion of 2% calcium hydroxide resulted in improved long-term bond strength to dentin. However, the inclusion of calcium hydroxide in the experimental adhesive systems tested was not able to release calcium (AU).

Effect of smear layer deproteinization on bonding of self-etch adhesives to dentin: a systematic review and meta-analysis

OBJECTIVES: The aim of this systematic review was to critically analyze previously published studies of the effects of dentin surface pretreatment with deproteinizing agents on the bonding of self-etch (SE) adhesives to dentin. Additionally, a meta-analysis was conducted to quantify the effects of the above-mentioned surface pretreatment methods on the bonding of SE adhesives to dentin. MATERIALS AND METHODS: An electronic search was performed using the following databases: Scopus, PubMed and ScienceDirect. The online search was performed using the following keywords: ‘dentin’ or ‘hypochlorous acid’ or ‘sodium hypochlorite’ and ‘self-etch adhesive.’ The following categories were excluded during the assessment process: non-English articles, randomized clinical trials, case reports, animal studies, and review articles. The reviewed studies were subjected to meta-analysis to quantify the effect of the application time and concentration of sodium hypochlorite (NaOCl) and hypochlorous acid (HOCl) deproteinizing agents on bonding to dentin. RESULTS: Only 9 laboratory studies fit the inclusion criteria of this systematic review. The results of the meta-analysis revealed that the pooled average microtensile bond strength values to dentin pre-treated with deproteinizing agents (15.71 MPa) was significantly lower than those of the non-treated control group (20.94 MPa). CONCLUSIONS: In light of the currently available scientific evidence, dentin surface pretreatment with deproteinizing agents does not enhance the bonding of SE adhesives to dentin. The HOCl deproteinizing agent exhibited minimal adverse effects on bonding to dentin in comparison with NaOCl solutions.

Evaluation of microshear bond strength and nanoleakage of etch‑and‑rinse and self‑etch adhesives to dentin pretreated with silver diamine fluoride/potassium iodide: An in vitro study.

Aims: The aim of this in vitro study was to comparatively evaluate the microshear bond strength (MSBS) of etch‑and‑rinse and self‑etch (ER and SE) bonding systems to dentin pretreated with silver diamine fluoride/potassium iodide (SDF/KI) and nanoleakage at the resin‑dentin interface using transmission electron microscope (TEM). Subjects and Methods: Seventy‑two dentin slabs of 3 mm thickness were prepared from extracted human permanent third molars and divided into four groups (n = 18) based on the dentin surface treatment as follows: (1) ER adhesive bonding without dentin pretreatment; (2) SDF/KI pretreatment of dentin followed by ER adhesive bonding; (3) SE adhesive bonding without dentin pretreatment; and (4) SDF/KI pretreatment of dentin followed by SE adhesive bonding. Resin composite was built on the dentin slabs to a height of 4 mm incrementally, and dentin‑composite beams of approximately 1 mm2 cross‑sectional area were prepared. The beams were subjected to MSBS analysis, and the fractured surface was observed under scanning electron microscope to determine the mode of failure. The resin‑dentin interface was examined under TEM for evaluation of nanoleakage. Statistical Analysis Used: One‑way ANOVA followed by Tukey’s post hoc multiple comparison tests. Results: Pretreatment of dentin with SDF/KI increased the MSBS of ER and SE adhesives, though not statistically significant, except between Groups 2 and 3. In all the groups, the predominant mode of failure was adhesive followed by cohesive in resin, mixed and cohesive in dentin. TEM examination of resin‑dentin interface showed that pretreatment with 38% SDF/KI reduced nanoleakage regardless of the type of bonding system used. Conclusions: Pretreatment of dentin with SDF/KI minimized nanoleakage at the resin‑dentin interface without adversely affecting the bond strength of resin composite to dentin.

Influence of Organic Acids from the Oral Biofilm on the Bond Strength of Self-Etch Adhesives to Dentin

Abstract: The aim of this study was to evaluate the microtensile bond strength of self-etch adhesive systems to dentin after storage in acids from oral biofilm. Three adhesive systems were used in the study: a two-step self-etch adhesive for use with a silorane-based resin composite (Filtek P90 adhesive system - P90), a two-step self-etch adhesive (Clearfil SE Bond - CSE) and a one-step self-etch adhesive (Adper Easy One - AEO). The bond strength of these products was evaluated by bonding resin composite (Filtek Z350 for CSE and AEO; and Filtek P90 for P90) to 90 bovine dentin tooth fragments, according to the manufacturer's instructions. After 24 h of water storage at 37 °C, the specimens were sectioned into beams (1 mm2) divided and stored in distilled water, lactic acid and propionic acid, for 7 and 30 days. After storage, the specimens were tested for microtensile bond strength. Data were analyzed by three-way ANOVA and Tukey´s test (α=0.05). CSE presented the highest microtensile bond strength after storage in distilled water for 7 and 30 days. The microtensile bond strength of all adhesive systems was lower after storage in lactic acid and propionic acid than after water storage. Significant difference was not found between storage times.

Resumo: O objetivo deste trabalho foi avaliar a resistência de união de sistemas adesivos autocondicionantes após estocagem em ácidos presentes no biofilme oral. Foram utilizados três sistemas adesivos: um autocondicionante de dois frascos indicado para uso com a resina composta à base de silorano (P90 System Adhesive- P90), um autocondicionante de dois frascos (Clearfil SE Bond - CSE) e um autocondicionante de frasco único (AdperEasyOne - AEO). Para avaliação da resistência de união à dentina, 90 fragmentos de dentes bovinos foram restaurados de acordo com as recomendações dos fabricantes. Após a confecção de blocos de resina composta (Filtek Z350 para os sistemas adesivos AEO e CSE; Filtek P90 para o sistema adesivo P90) e estocagem em água destilada por 24 h a 37 °C, os fragmentos foram seccionados para a obtenção de palitos (1 mm2) que foram divididos e estocados nos três diferentes meios de imersão (água destilada, ácido lático e ácido propiônico) por períodos de 7 dias e 30 dias (n=5). Em seguida, foi realizado o ensaio de resistência à microtração. Os dados foram submetidos à Análise de Variância (3 fatores) e ao Teste de Tukey (α=0,05). O sistema adesivo CSE apresentou maior resistência de união após imersão em água por 7 ou 30 dias. A resistência de união de todos os sistemas adesivos foi menor após imersão em ácido lático e propiônico do que após imersão em água. Não foi observada diferença significativa entre os tempos de imersão.

Rol del 10-metacriloxidecilfosfato dihidrogenado en el cambio de paradigma de los sistemas adhesivos integrados en la dentina / The Role of 10-methacryloyloxydecyl dihydrogen phosphate in the paradigm of change to adhesive systems integrated to dentin

La aplicación de adhesivos dentarios autograbantes que contienen 10-metacriloxidecilfosfato dihidrogenado supera la resistencia a la biodegradación de la interfase adhesiva de los sistemas tradicionales de grabado total. El mecanismo de acción se basa en la formación de múltiples nanocapas de calcio unido a 2 moléculas 10-metacriloxidecilfosfato dihidrogenado sobre la dentina; estas múltiples capas de 3,5 nm son las que protegerían las fibras colágenas del fenómeno de hidrólisis. Las nanocapas explicarían su alta estabilidad en el tiempo y la fortaleza de la unión, probadas tanto en estudios clínicos como de laboratorio. La interacción con la hidroxiapatita sucede con ácidos de pH bajos, pero mayores que los tradicionales, por lo que surge la necesidad de recomendar el grabado selectivo previo del esmalte. El uso de metacriloxidecilfosfato dihidrogenado permite el cambio de filosofía adhesiva desde el grabado total a la integración adhesiva de la dentina.

Applying self-etching dental adhesives containing 10-MDP overcomes the resistance to biodegradation of the adhesive interface of traditional total etch. The mechanism of action is based on the formation of multiple nano-layers of calcium and two molecules of 10-MDP on the dentin surface. These multiple layers of 3.5 nm protect the collagen fibers from hydrolysis phenomenon. The nano-layer explains its high stability and bond strength over time, tested both by clinical and laboratory studies. Hydroxyapatite interaction occurs with acids of low pH, but are higher than traditional, thus increasing the need to recommend the previous selective etching of the enamel. The use of MDP allows a change of philosophy from the total-etch adhesive to adhesive integration of the dentin.

"A Microleakage Study of Class V Restorations Uisng Thee Self- Etching Adhesives And Microfill Conposite Resin- An Vitro Stereo Microscopic Study.

AIM: This study evaluates marginal sealing ability of currently available three self-etching adhesives in class V micro fill composite restorations. Materials and methods: Forty five human central incisors, divided in to three groups and class V cavities were prepared on the facial surface of teeth with occlusal margin in enamel and gingival margin in dentin/cementum. The cavities were restored with microfill composite in two increments using three different adhesives, Ader prompt (3M Dental products), AdheSE (Ivolar Vicadent) and I-Bond (Heraeus Kulzer). Each group containing fifteen teeth were subjected to thermocycling and dye penetration. The teeth were mlunted and sectioned buccolingually with a hard tissue microtome, the two sections from earch tooth obtained from the both mesial and distal acute angles of the cavity preparation, examined under stereomicrscope. The values were analyzed with Chi-Square test and Fisher exact. Results: The results show less leakage in enamel and dentin margin for AdheSE. This is significantly less than Adper Prompt an IBond which showed no statistically significant difference. Conclusion: At enamel and dentin/ Cementum margins, two step self etch adhesive AdheSE performed better than one step self etch adhesives Adper Prompt and I-Bond.

Marginal microleakage of resin-modified glass-ionomer and composite resin restorations: Effect of using etch-and-rinse and self-etch adhesives.

Objectives: Previous studies have shown that dental adhesives increase the bond strength of resin-modified glass-ionomer (RMGI) restorative materials to dentin. This in vitro study has evaluated the effect of etch-and-rinse and self-etch bonding systems v/s cavity conditioner, and in comparison to similar composite resin restorations on maintaining the marginal sealing of RMGI restorations. Materials and Methods: 98 rectangular cavities (2.5×3×1.5 mm) were prepared on buccal and palatal aspects of 49 human maxillary premolars, randomly divided into 7 groups (N=14). The cavities in groups 1, 2 and 3 were restored using a composite resin (APX). The cavities in groups 4, 5, 6 and 7 were restored using a resin-modified glass-ionomer (Fuji II LC). Before restoring, adhesive systems (Optibond FL = OFL, three-step etch-and-rinse; One Step Plus = OSP, two-step etch-and-rinse; Clearfil Protect Bond = CPB, two-step self-etch) were used as bonding agents in groups 1-6 as follow: OFL in groups 1 and 4, OSP in groups 2 and 5, and CPB in groups 3 and 6, respectively. The specimens in group 7 were restored with GC cavity conditioner and Fuji II LC. All the specimens were thermo-cycled for 1000 cycles. Microleakage scores were determined using dye penetration method. Statistical analyzes were carried out with Kruskal-Wallis and Mann-Whitney U tests (α=0.05). Results: There were significant differences in microleakage scores at both enamel and dentinal margins between the study groups (P<0.05). The lowest microleakage scores at enamel and dentin margins of RMGI restorations were observed in group 6. Conclusion: Use of two-step self-etch adhesive, prior to restoring cervical cavities with RMGIC, seems to be more efficacious than the conventional cavity conditioner in decreasing marginal microleakage.

Adesivos Autocondicionantes: Efeito do Condicionamento Ácido e Proteolítico na Resistência de União / Self-etch Adhesive Systems: Effect of Acid and Proteolytic Etching on Bond Strength

Objetivo: Avaliar a resistência de união à dentina de quatro sistemas adesivos autocondicionantes empregando diferentes estratégias de união. Método: Sessenta molares humanos foram utilizados, sendo seccionados no sentido mésio-distal. As hemi-secções (V e L) foram distribuídas aleatoriamente em quatro grupos: G1: Clearfil SE Bond (Kuraray), G2: AdheSE (Dentsply), G3: Self Etch (Vigodent) e G4: Vitremer (3M/ESPE). Cada grupo foi dividido em três subgrupos (n=10), de acordo com a estratégia de união empregada: manutenção (a), remoção da smear layer (b) ou remoção do colágeno (c), respectivamente. Para confecção dos cilindros de resina composta foi utilizado uma matriz metálica bipartida, sendo o compósito inserido em incrementos e fotoativado por 40s. Em seguida, todos os corpos de prova foram armazenados em água destilada, por 24 horas, a 37ºC até a realização do ensaio de cisalhamento. Para a análise dos dados foram obtidas o valor mínimo e máximo, média, mediana, desvio padrão e coeficiente de variação e utilizados os testes F (ANOVA) para dois fatores com interação, F (ANOVA) para um fator e de comparações pareadas de Tukey, para um nível de significância de 5% (alfa = 0,05). Resultados: Independente da estratégia de união, os valores médios da resistência união foram mais elevados para o grupo G1. Comprovou-se diferença significante entre os adesivos Clearfil SE Bond e Self Etch Bond com cada um dos outros adesivos quando foi aplicado conforme o fabricante (sem remoção da smear layer); entre o Clearfil SE Bond com os demais adesivos quando utilizada a remoção da smear layer ou a remoção do colágeno. Conclusão: Não se justifica mudanças nas estratégias de união através do autocondicionamento destes sistemas adesivos quando aplicado conforme recomenda o fabricante.

Objective: To evaluate the bond strength to dentin of four self-etch adhesive systems using different bond strategies. Methods: Sixty human molars were sectioned in the mesiodistal direction. The hemi-sections (B and L) were randomly assigned to four groups: G1: Clearfil SE Bond (Kuraray), G2: AdheSE (Dentsply), G3: Self Etch (Vigodent) and G4: Vitremer (3M/ESPE). Each group was divided in 3 subgroups (n=10), according the bond strategy: maintenance (a), removal of smear layer (b) or removal of collagen (c), respectively. A split metallic matrix was used for fabrication of composite resin cylinders, the material being inserted in increments photoactivated during 40 seconds. All specimens were stored in distilled water at 37oC during 24 hours until the shear bond strength test. The minimum and maximum values, mean, median, standard deviation and variation coefficient were calculated and analyzed using two-way F test (ANOVA) with interaction, one-way F test (ANOVA) and Tukey's paired comparisons at a significance level of 5% (alpha = 0.05). Results: Regardless of the bond strategy, G1 presented the highest mean bond strength values. Clearfil SE Bond and Self Etch Bond differed significantly (p<0.05) from the other adhesive systems when used according to the manufacturers' instructions (no smear layer removal). Clearfil SE Bond differed significantly from the other adhesive systems when smear layer or collagen was removed. Conclusion: Changes in the bond strategies of self-etch adhesive systems are not justified when they are applied according to the manufacturers' instructions.

Adesivos autocondicionantes: efeito do condicionamento ácido e proteolítico na resistência de União / Self-etch adhesive systems: effect of acid and proteolytic etching on bond strength

Objetivo: Avaliar a resistência de união à dentina de quatro sistemas adesivos autocondicionantes empregando diferentes estratégias de união. Método: Sessenta molares humanos foram utilizados, sendo seccionados no sentido mésio-distal. As hemi-secções (V e L) foram distribuídas aleatoriamente em quatro grupos: G1: Clearfil SE Bond (Kuraray), G2: AdheSE (Dentsply), G3: Self Etch (Vigodent) e G4: Vitremer (3M/ESPE). Cada grupo foi dividido em três subgrupos (n=10), de acordo com a estratégia de união empregada: manutenção (a), remoção da smear layer (b) ou remoção do colágeno (c), respectivamente. Para confecção dos cilindros de resina composta foi utilizado uma matriz metálica bipartida, sendo o compósito inserido em incrementos e fotoativado por 40s. Em seguida, todos os corpos de prova foram armazenados em água destilada, por 24 horas, a 37ºC até a realização do ensaio de cisalhamento. Para a análise dos dados foram obtidas o valor mínimo e máximo, média, mediana, desvio padrão e coeficiente de variação e utilizados os testes F (ANOVA) para dois fatores com interação, F (ANOVA) para um fator e de comparações pareadas de Tukey, para um nível de significância de 5% (alfa = 0,05). Resultados: Independente da estratégia de união, os valores médios da resistência união foram mais elevados para o grupo G1. Comprovou-se diferença significante entre os adesivos Clearfil SE Bond e Self Etch Bond com cada um dos outros adesivos quando foi aplicado conforme o fabricante (sem remoção da smear layer); entre o Clearfil SE Bond com os demais adesivos quando utilizada a remoção da smear layer ou a remoção do colágeno. Conclusão: Não se justifica mudanças nas estratégias de união através do autocondicionamento destes sistemas adesivos quando aplicado conforme recomenda o fabricante.

Objective: To evaluate the bond strength to dentin of four self-etch adhesive systems using different bond strategies. Methods: Sixty human molars were sectioned in the mesiodistal direction. The hemi-sections (B and L) were randomly assigned to four groups: G1: Clearfil SE Bond (Kuraray), G2: AdheSE (Dentsply), G3: Self Etch (Vigodent) and G4: Vitremer (3M/ESPE). Each group was divided in 3 subgroups (n=10), according the bond strategy: maintenance (a), removal of smear layer (b) or removal of collagen (c), respectively. A split metallic matrix was used for fabrication of composite resin cylinders, the material being inserted in increments photoactivated during 40 seconds. All specimens were stored in distilled water at 37oC during 24 hours until the shear bond strength test. The minimum and maximum values, mean, median, standard deviation and variation coefficient were calculated and analyzed using two-way F test (ANOVA) with interaction, one-way F test (ANOVA) and Tukey's paired comparisons at a significance level of 5% (alpha = 0.05). Results: Regardless of the bond strategy, G1 presented the highest mean bond strength values. Clearfil SE Bond and Self Etch Bond differed significantly (p<0.05) from the other adhesive systems when used according to the manufacturers' instructions (no smear layer removal). Clearfil SE Bond differed significantly from the other adhesive systems when smear layer or collagen was removed. Conclusion: Changes in the bond strategies of self-etch adhesive systems are not justified when they are applied according to the manufacturers' instructions.

Enamel adhesion of light- and chemical-cured composites coupled by two step self-etch adhesives / 대한치과보존학회지

This study was to compare the microshear bond strength (microSBS) of light- and chemically cured composites to enamel coupled with four 2-step self-etch adhesives and also to evaluate the incompatibility between 2-step self-etch adhesives and chemically cured composite resin. Crown segments of extracted human molars were cut mesiodistally, and a 1 mm thickness of specimen was made. They were assigned to four groups by adhesives used: SE group (Clearfil SE Bond), AdheSE group (AdheSE), Tyrian group (Tyrian SPE/One-Step Plus), and Contax group (Contax). Each adhesive was applied to a cut enamel surface as per the manufacturer's instruction. Light-cured (Filtek Z250) or chemically cured composite (Luxacore Smartmix Dual) was bonded to the enamel of each specimen using a Tygon tube. After storage in distilled water for 24 hours, the bonded specimens were subjected to microSBS testing with a crosshead speed of 1 mm/minute. The mean microSBS (n=20 for each group) was statistically compared using two-way ANOVA, Tukey HSD, and t test at 95% level. Also the interface of enamel and composite was evaluated under FE-SEM. The results of this study were as follows; 1. The microSBS of the SE Bond group to the enamel was significantly higher than that of the AdheSE group, the Tyrian group, and the Contax group in both the light-cured and the chemically cured composite resin (p < 0.05). 2. There was not a significant difference among the AdheSE group, the Tyrian group, and the Contax group in both the light-cured and the chemically cured composite resin. 3. The microSBS of the light-cured composite resin was significantly higher than that of the chemically cured composite resin when same adhesive was applied to the enamel (p < 0.05). 4. The interface of enamel and all 2-step self-etch adhesives showed close adaptation, and so the incompatibility of the chemically cured composite resin did not show.

Enamel adhesion of light- and chemical-cured composites coupled by two step self-etch adhesives / 대한치과보존학회지

This study was to compare the microshear bond strength (microSBS) of light- and chemically cured composites to enamel coupled with four 2-step self-etch adhesives and also to evaluate the incompatibility between 2-step self-etch adhesives and chemically cured composite resin. Crown segments of extracted human molars were cut mesiodistally, and a 1 mm thickness of specimen was made. They were assigned to four groups by adhesives used: SE group (Clearfil SE Bond), AdheSE group (AdheSE), Tyrian group (Tyrian SPE/One-Step Plus), and Contax group (Contax). Each adhesive was applied to a cut enamel surface as per the manufacturer's instruction. Light-cured (Filtek Z250) or chemically cured composite (Luxacore Smartmix Dual) was bonded to the enamel of each specimen using a Tygon tube. After storage in distilled water for 24 hours, the bonded specimens were subjected to microSBS testing with a crosshead speed of 1 mm/minute. The mean microSBS (n=20 for each group) was statistically compared using two-way ANOVA, Tukey HSD, and t test at 95% level. Also the interface of enamel and composite was evaluated under FE-SEM. The results of this study were as follows; 1. The microSBS of the SE Bond group to the enamel was significantly higher than that of the AdheSE group, the Tyrian group, and the Contax group in both the light-cured and the chemically cured composite resin (p < 0.05). 2. There was not a significant difference among the AdheSE group, the Tyrian group, and the Contax group in both the light-cured and the chemically cured composite resin. 3. The microSBS of the light-cured composite resin was significantly higher than that of the chemically cured composite resin when same adhesive was applied to the enamel (p < 0.05). 4. The interface of enamel and all 2-step self-etch adhesives showed close adaptation, and so the incompatibility of the chemically cured composite resin did not show.

Microshear bond strength of adhesives according to the direction of enamel rods / 대한치과보존학회지

This study compared the microshear bond strength (microSBS) to end and side of enamel rod bonded by four adhesives including two total etch adhesives and two self-etch adhesives. Crown segments of extracted human molars were cut mesiodistally. The outer buccal or lingual surface was used as specimens cutting the ends of enamel rods, and inner slabs used as specimens cutting the sides of enamel rods. They were assigned to four groups by used adhesives: Group 1 (All-Bond 2), Group 2 (Single Bond), Group 3 (Tyrian SPE/One-Step Plus), Group 4 (Adper Prompt L-Pop). After each adhesive was applied to enamel surface, three composite cylinders were adhered to it of each specimen using Tygon tube. After storage in distilled water for 24 hours, the bonded specimens were subjected to microSBS testing with a crosshead speed of 1 mm/minute. The results of this study were as follows; 1. The microSBS of Group 2 (16.50 +/- 2.31 MPa) and Group 4 (15.83 +/- 2.33 MPa) to the end of enamel prism was significantly higher than that of Group 1 (11.93 +/- 2.25 MPa) and Group 3 (11.97 +/- 2.05 MPa) (p < 0.05). 2. The microSBS of Group 2 (13.43 +/- 2.93 MPa) to the side of enamel prism was significantly higher than that of Group 1 (8.64 +/- 1.53 MPa), Group 3 (9.69 +/- 1.80 MPa), and Group 4 (10.56 +/- 1.75 MPa) (p < 0.05). 3. The mean microSBS to the end of enamel rod was significantly higher than that to the side of enamel rod in all group (p < 0.05).