Effects of applying procyanidins on the bond strength of bleached dentin to composite resin / 口腔疾病防治

Objective@#To study the influence of procyanidins on the bonding strength of dentin bleached by carbamide peroxide to composite resin.@*Methods @#By applying different treatments to dentin bonding interfaces, 120 human third molars were randomly divided into 12 groups (n = 10): W group (no bleaching+deionized water), Wa group (no bleaching+deionized water+aging), WT1 group (no bleaching+5% procyanidins for 1 min), WT1a group (no bleaching+5% procyanidins for 1 min+aging), WT2 group (no bleaching+5% procyanidins for 5 min), WT2a group (no bleaching+5% procyanidins for 5 min+aging), C group (carbamide peroxide+deionized water), Ca group (carbamide peroxide+deionized water+aging), CT1 group (carbamide peroxide+5% procyanidins for 1 min), CT1a group (carbamide peroxide+5% procyanidins for 1 min+aging), CT2 group (carbamide peroxide+5% procyanidins for 5 min), and CT2a group (carbamide peroxide+5% procyanidins for 5 min+aging). The bond strength to composite resin was measured by universal mechanical testing machine, microstructure and the nanoleakages were measured by scanning electron microscope immediately or after the thermal cycling aging test.@*Results@#The immediate bond strength of the bleached groups pretreated with procyanidins for 1 min (P<0.001) and 5 min (P<0.001) was higher than that of Group C, and the difference was statistically significant. Meanwhile, there was no statistically significant difference between Group CT1 and Group CT2 (P = 1.000). After the thermal cycles, the bond strength of each group declined. The differences between Group W and Group Wa (P<0.001) and Group C and Group Ca (P<0.001) were statistically significant, but no significant differences between Group CT1 and Group CT1a (P = 0.052) or Group CT2 and Group CT2a (P = 0.053) were found. The main effects of “aging” (P<0.001), “bleaching” (P<0.001) and “procyanidins” (P<0.001) and the second-order interaction effects of “bleaching * procyanidins” (P = 0.008), “bleaching * aging” (P = 0.024), and “aging * procyanidins” (P<0.001) were statistically significant. SEM observations showed that the hybrid layers in Groups C, CT1 and CT2 were not clear, and the hybrid layers in Groups Ca, CT1a and CT2a were partially destroyed and disintegrated. Under backscattering mode, it was observed that there were a large number of silver nitrate particles in the hybrid layer of Group Ca, and the residual silver ions in the hybrid layer of Groups CT1a and CT2a were decreased. @*Conclusion@# Pretreatment with 5% procyanidins for 1 min can improve the immediate bond strength of dentin bleached by carbamide peroxide to composite resin and maintain bonding durability.

Randomized clinical trial of four adhesion strategies: A 42 month study

Context: The adhesives clinical effectiveness has been extensively reported for noncarious cervical lesions (NCCLs). However, there is a lack of information about the adhesive systems strategies and their effect on NCCL restoration longevity. Aims: This study aims to evaluate a 42-month performance of four dentin adhesive systems used for the restorative treatment of NCCLs. Settings and Design: NCCLs were randomly divided into four groups: (1) Scotchbond multi-purpose (MP); 2: Single bond plus (SB); 3: Scotchbond SE (SE); and 4: Easy bond (EB). Subjects and Methods: NCCLs (125) were randomly distributed: (1) MP; (2) SB; (3) SE; and (4) EB and were restored with a nanofilled resin-composite, evaluated along 18-36-42 months. Statistical Analysis Used: Kruskal–Wallis test: Comparison among the adhesive systems in each period. Friedman analysis: Comparison along the periods. Kaplan–Meier: Survival analysis. Results: Baseline and 42-month retention (RET) rates (%) were 100/100 for MP; 100/94.74 for SB; 100/87.5 for SE; and 100/100 for EB. The cumulative failure percentage was 9.52% for MP, 9.52% SB, 15.8% SE, and 10% EB. Restorations survival was not dependent on the used adhesive type. Marginal adaptation (MA) was similar to each group, but EB presented noticeable marginal deterioration. Wear was noticed in the 3-step etch-and-rinse (MP) restorations evaluated after 42 months. For the EB, baseline and 18-month wear evaluation were statistically similar. After 36 and 42 months, wear was also similar for EB. Conclusions: Adhesive systems showed similar performance within most important adhesive bonding efficiency achievement parameters: RET, MA, interfacial staining, recurrent caries, and postoperative sensitivity evaluated during 42 months.

In vitro evaluation of the antibacterial behavior of a self-etch adhesive associated with chlorhexidine / Avaliação in vitro da ação anti-bacteriana de um adesivo auto-condicionante acrescido de clorexidina

Abstract Introduction Adhesive technology has been developed quickly since its introduction about fifty years ago. Its goal is to produce a close contact within enamel and dentin. Failures in this process could result in microleakage, and allow the infiltration of bacteria, fluids and ions. Recent studies have been shown the use of chlorhexidine associated with adhesive systems can be able to inhibit the bacteria action. Objective The aim of this study was to evaluate the addiction of different percentages of chlorhexidine to a self-etch adhesive. Methodology The solution of digluconatechlorhexidine was increased to the primer of the two pass self etch adhesive to create a 0.5%, 1.0% and 2.0% chlorhexidine primer solution and after they were distributed in four groups (G1, G2, G3 and G4). Saliva samples (N=10) were used to test bacteria activity. Result They were spread in a blood medium with filter paper disks containing the different treatments. After the incubation, the inhibitions halos formation were evaluated. Conclusion This study demonstrated that, in vitro, the addition of different percentages of chlorhexidine digluconate to the self-etch adhesive induced inhibited halos at bacteria of saliva samples, independent from their concentration.

Resumo Introdução A tecnologia adesiva vem se desenvolvendo rapidamente desde que foi introduzida há mais de 50 anos. O principal objetivo da adesão é alcançar um íntimo contato entre a estrutura dental e o material restaurador e fornecer adequada união entre o esmalte e a dentina. Objetivo A proposta deste estudo foi avaliar o efeito antibacteriano de um adesivo auto-condicionante de dois passos associado a diferentes concentrações de solução de digluconato de clorexidina (DCHX). Metodologia A solução de digluconato de clorexidina a 20% foi adicionada ao primer do sistema adesivo nas concentrações de 0,5, 1,0 e 2,0% e distribuídas em quatro grupos (G1, G2, G3 e G4). Para o teste de atividade antibacteriana foram utilizadas amostras de saliva (N=10) semeadas em meio de ágar sangue e discos de papel filtro contendo os diferentes grupos. Após incubação, as amostras foram inspecionadas quanto à formação de halo de inibição dos microrganismos através da utilização do paquímetro digital de precisão (0,0001mm) (Mitutoyou Sul Americana Ltda/ Starret Tools ®). Resultado Halos de inibição foram encontrados ao redor de todos os discos de filtro em que foram aplicados o primer acrescido de clorexidina mais o adesivo, bem como ao redor dos discos do controle positivo. Ao redor dos discos do controle negativo e dos discos com primer e adesivo não modificado não foram observados halos de inibição. Conclusão Este trabalho demonstrou que, in vitro, a adição de diferentes concentrações de digluconato de clorexidina ao sistema adesivo produziu halo de inibição dos microrganismos presentes nas amostras de saliva, independente da concentração utilizada.

Shear Bond Strength Comparison of Different Adhesive Systems to Calcium Silicate-based Materials / 대한소아치과학회지

The aim of this study was to measure the shear bond strength (SBS) of different adhesive systems to calcium silicate-based materials (Biodentine and RetroMTA). Eighty cylindrical acrylic blocks, with a hole (5.0 mm diameter, 2.0 mm height) in each, were prepared. The holes were filled with Biodentine (BD) and RetroMTA (RMTA), and the specimens were divided into 2 groups. Each group was classified into 4 subgroups: Clearfil™ SE (CSE) ; AQ bond (AQ) ; All bond universal Self-etch (ABU-SE) ; and All bond universal Total-etch (ABU-TE). After the application of different adhesive systems, composite resin (Z350) was applied over BD and RMTA. The SBS was measured using a universal testing machine, and the data were compared using the Kruskal-Wallis test and the Mann-Whitney test. The highest and lowest values of SBS were observed for BD-ABU-SE and RMTA-AQ, respectively. No significant differences were found in the SBS between ABU-TE and ABU-SE and between ABU-TE and CSE to BD and RMTA. According to the data, BD showed a higher SBS than did RMTA when BD and RMTA are compared in the same adhesive agents. Further, among all groups, composite resin with ABU-SE showed better bond strength to BD and RMTA.

The influence of dentin depths on the shear bond strenghth of different adhesives under simulated pulpal pressure / 实用口腔医学杂志

Objective: To determine the shear bond strength of different adhesive systems to superficial and deep dentin under simulated pulpal pressure. Methods: Occlusal surfaces of 72 sound extracted noncarious human molars were ground to obtain flat dentin surfaces(36 superficial and 36 deep dentin). Each dentin groups was randomly asssigned into 3 groups(n = 12): Clearfil SE Bond(SE), Clearfil S3 Bond(S3) and Prime&Bond NT(PB). All of samples were tested under simulated pulpal pressure. After bonding procedures with 3 adhesives respectively,all samples were covered with nail vanishi. The shear bond strength was tested after the samples stored for 24 h under simulated pulpal pressure. Results: The bond strength of PB to superficial and deep was (17. 11 ± 2. 71) and(11. 13 ± 3. 60) MPa(P ＜ 0. 05),that of SE (16. 53 ± 5. 29) and (14. 78 ± 4. 53) MPa(P＞ 0. 05),S3 (9. 08 ± 1. 74) and (8. 43 ± 1. 41) MPa(P＞ 0. 05). Conclusion: Bond strengths of phosphoric acid etching system decreases with an increase of dentin depth, that of two-step self-etch adhesive system is not affected by the depth.

Cytotoxicity of Universal, Self-Etching and Etch-and-Rinse Adhesive Systems According to the Polymerization Time

This in vitro study evaluated in fibroblast cultures the direct cytotoxicity of universal, self-etching and etch-and-rinse adhesive systems according to the polymerization time. Paper discs were impregnated with adhesives and light-cured (10, 20 or 40 s). The discs were then immersed in culture medium to obtain the eluates for the experimental groups (A1-Single Bond 2; A2-Scotchbond Multi-purpose; A3-Clearfil SE Bond; A4 Scotchbond Universal). As a negative control, paper discs were immersed in culture medium only. After 24 h or 7 days, the eluate obtained was applied on fibroblast culture. Cell viability, cell morphology, membrane damage and the presence of residual monomers were evaluated by MTT assay, SEM, flow cytometry and high-performance liquid chromatography (HPLC), respectively. Data were analyzed by Kruskal-Wallis and Mann-Whitney tests (=0.05). All adhesive systems significantly reduced 33-51% cell metabolism when compared to the negative control, regardless of polymerization time, storage period and adhesive system. Moreover, the adhesives caused intense morphological alterations and cell membrane damage. Toxicity was directly related to the presence of residual monomers in the eluates. Residual monomers and additional components are capable of reducing mitochondrial activity, causing morphological alterations and disruption of the cell membrane in fibroblasts, regardless of the polymerization time. This study highlights that despite the more complex composition of the universal adhesive system, its biological response was not more toxic when compared with other systems, even when the shortest polymerization time was tested in cell culture.

O presente estudo in vitro avaliou a citotoxicidade direta dos sistemas adesivos convencionais, autocondicionantes e universais de acordo com o tempo de polimerização em cultura de fibroblastos. Discos de papel foram impregnados com adesivos e fotoativados (10, 20 e 40 s). Os discos foram posteriormente imersos em meio de cultura para obtenção dos eluatos dos grupos experimentais (A1-Single Bond 2; A2-Scotchbond Multi-purpose; A3-Clearfil SE Bond; A4 Scotchbond Universal). Para o controle negativo, os discos de papel foram imersos somente em meio de cultura. Após 24 h ou 7 dias, o eluato obtido foi aplicado na cultura de fibroblastos. O metabolismo celular, morfologia, dano de membrana e presença de monômeros residuais foram avaliados por teste de MTT, MEV, citometria de fluxo e HPLC, respectivamente. Os dados foram analisados estatisticamente por Kruskal-Wallis e Mann-Whitney. Todos os sistemas adesivos reduziram significativamente o metabolismo celular em 33 a 51% quando comparados ao grupo controle, independente do tempo de polimerização, período de armazenamento e tipo de sistema adesivo. O eluato do adesivos causou ainda intensas alterações morfológicas e danos à membrana celular. A toxicidade foi diretamente relacionada à presença de monômeros residuais nos eluatos experimentais. Monômeros residuais e componentes adicionais dos sistemas adesivos foram capazes de reduzir a atividade mitocondrial, causar alterações morfológicas e danos à membrana citoplasmática de fibroblastos, independente do tempo de polimerização. Esse estudo evidencia que apesar de uma composição mais complexa do sistema adesivo universal, sua resposta biológica não apresentou maior toxicidade quando comparado aos demais sistemas, mesmo no menor tempo de polimerização quando testados em cultura celular.

Micro-CT evaluation of internal adaptation in resin fillings with different dentin adhesives

OBJECTIVES: The purpose of present study was to evaluate the internal adaptation of composite restorations using different adhesive systems. MATERIALS AND METHODS: Typical class I cavities were prepared in 32 human third molars. The teeth were divided into the following four groups: 3-step etch-and-rinse, 2-step etch-and-rinse, 2-step self-etch and 1-step self-etch system were used. After the dentin adhesives were applied, composite resins were filled and light-cured in two layers. Then, silver nitrate solution was infiltrated, and all of the samples were scanned by micro-CT before and after thermo-mechanical load cycling. For each image, the length to which silver nitrate infiltrated, as a percentage of the whole pulpal floor length, was calculated (%SP). To evaluate the internal adaptation using conventional method, the samples were cut into 3 pieces by two sectioning at an interval of 1 mm in the middle of the cavity and they were dyed with Rhodamine-B. The cross sections of the specimens were examined by stereomicroscope. The lengths of the parts where actual leakage was shown were measured and calculated as a percentage of real leakage (%RP). The values for %SP and %RP were compared. RESULTS: After thermo-mechanical loading, all specimens showed significantly increased %SP compared to before thermo-mechanical loading and 1-step self-etch system had the highest %SP (p < 0.05). There was a tendency for %SP and %RP to show similar microleakage percentage depending on its sectioning. CONCLUSIONS: After thermo-mechanical load cycling, there were differences in internal adaptation among the groups using different adhesive systems.

The Effect of Sodium Hypochlorite Treatment On The Shear Bond Strength of An Acetone - Based Adhesive System to Dentin - An In Vitro Study.

Aim: The aim of the present study was to evaluate the effects of different concentrations of sodium hypochlorite applied for 30 seconds on acid etched dentin on the shear bond strengths of an acetone-based adhesive. Materials and Methods: 40 freshly extracted molars were used as specimens to evaluate shear bond strength of composite to sodium hypochlorite (NaOCl)-treated dentin using Prime and Bond NT dentin bonding agent after 10% NaOCl (Group I), 5% NaOCl (Group II), 2.5% NaOCl (Group III) and No NaOCl (Control) treatment. Shear bond strengths of all specimens were measured using an Intron Universal Testing Machine. Results: Group II demonstrated higher bond strengths than Groups I, III and IV. Groups I, III and IV did not show any statistically significant differences in their bond strengths. Group III demonstrated the least bond strength. Group I showed similar bond strength as that of Group IV. Conclusion: Highest shear bond strength values were demonstrated by Group II i.e. 5% sodium hypochlorite treatment group. This could be because of partial decollagenation and formation of an optimum hybrid layer.

The effect of the strength and wetting characteristics of Bis-GMA/TEGDMA-based adhesives on the bond strength to dentin / 대한치과보존학회지

OBJECTIVES: This study investigated the effect of the strength and wetting characteristics of adhesives on the bond strength to dentin. The experimental adhesives containing various ratios of hydrophobic, low-viscosity Bis-M-GMA, with Bis-GMA and TEGDMA, were made and evaluated on the mechanical properties and bond strength to dentin. MATERIALS AND METHODS: Five experimental adhesives formulated with various Bis-GMA/Bis-M-GMA/TEGDMA ratios were evaluated on their viscosity, degree of conversion (DC), flexural strength (FS), and microtensile bond strength (MTBS). The bonded interfaces were evaluated with SEM and the solubility parameter was calculated to understand the wetting characteristics of the adhesives. RESULTS: Although there were no significant differences in the DC between the experimental adhesives at 48 hr after curing (p > 0.05), the experimental adhesives that did not contain Bis-GMA exhibited a lower FS than did those containing Bis-GMA (p < 0.05). The experimental adhesives that had very little to no TEGDMA showed significantly lower MTBS than did those containing a higher content of TEGDMA (p < 0.05). The formers exhibited gaps at the interface between the adhesive layer and the hybrid layer. The solubility parameter of TEGDMA approximated those of the components of the primed dentin, rather than Bis-GMA and Bis-M-GMA. CONCLUSIONS: To achieve a good dentin bond, a strong base monomer, such as Bis-GMA, cannot be completely replaced by Bis-M-GMA for maintaining mechanical strength. For compatible copolymerization between the adhesive and the primed dentin as well as dense cross-linking of the adhesive layer, at least 30% fraction of TEGDMA is also needed.

Bonding efficacy of cured or uncured dentin adhesives in indirect resin / 대한치과보존학회지

OBJECTIVES: This study examined the effect of the uncured dentin adhesives on the bond interface between the resin inlay and dentin. MATERIALS AND METHODS: Dentin surface was exposed in 24 extracted human molars and the teeth were assigned to indirect and direct resin restoration group. For indirect resin groups, exposed dentin surfaces were temporized with provisional resin. The provisional restoration was removed after 1 wk and the teeth were divided further into 4 groups which used dentin adhesives (OptiBond FL, Kerr; One-Step, Bisco) with or without light-curing, respectively (Group OB-C, OB-NC, OS-C and OS-NC). Pre-fabricated resin blocks were cemented on the entire surfaces with resin cement. For the direct resin restoration groups, the dentin surfaces were treated with dentin adhesives (Group OB-D and OS-D), followed by restoring composite resin. After 24 hr, the teeth were assigned to microtensile bond strength (microTBS) and confocal laser scanning microscopy (CLSM), respectively. RESULTS: The indirect resin restoration groups showed a lower microTBS than the direct resin restoration groups. The microTBS values of the light cured dentin adhesive groups were higher than those of the uncured dentin adhesive groups (p < 0.05). CLSM analysis of the light cured dentin adhesive groups revealed definite and homogenous hybrid layers. However, the uncured dentin adhesive groups showed uncertain or even no hybrid layer. CONCLUSIONS: Light-curing of the dentin adhesive prior to the application of the cementing material in luting a resin inlay to dentin resulted in definite, homogenous hybrid layer formation, which may improve the bond strength.

The effect of the removal of chondroitin sulfate on bond strength of dentin adhesives and collagen architecture / 대한치과보존학회지

Proteoglycan is highly hydrophilic and negatively charged which enable them attract the water. The objective of study was to investigate the effects of Proteoglycan on microtensile bond strength of dentin adhesives and on architecture of dentin collagen matrix of acid etched dentin by removing the chondroitin sulphate attached on Proteoglycan. A flat dentin surface in mid-coronal portion of tooth was prepared. After acid etching, half of the specimens were immersed in 0.1 U/mL chondroitinase ABC (C-ABC) for 48 h at 37degrees C, while the other half were stored in distilled water. Specimens were bonded with the dentin adhesive using three different bonding techniques (wet, dry and re-wet) followed by microtensile bond strength test. SEM examination was done with debonded specimen, resin-dentin interface and acid-etched dentin surface with/without C-ABC treatment. For the subgroups using wet-bonding or dry-bonding technique, microtensile bond strength showed no significant difference after C-ABC treatment (p > 0.05). Nevertheless, the subgroup using rewetting technique after air dry in the Single Bond 2 group demonstrated a significant decrease of microtensile bond strength after C-ABC treatment. Collagen architecture is loosely packed and some fibrils are aggregated together and relatively collapsed compared with normal acid-etched wet dentin after C-ABC treatment. Further studies are necessary for the contribution to the collagen architecture of noncollagenous protein under the various clinical situations and several dentin conditioners and are also needed about long-term effect on bond strength of dentin adhesive.

The effect of solvent evaporation of dentin adhesive on bonding efficacy / 대한치과보존학회지

OBJECTIVES: The purpose of this study is to evaluate bonding efficacy by means of measuring the effect of remained solvent on Degree of conversion(DC) and microTBS and FE-SEM examination. MATERIALS AND METHODS: Two 2-step total etching adhesives and two single-step self etching adhesives were used in this study. First, volume weight loss of 4 dentin adhesives were measured using weighting machine in process of time in normal conditions and calculate degree of evaporation (DE). Reaction/reference intensity ratio were measured using micro-Raman spectroscopy and calculate DC according to DE. Then 2 experimental groups were prepared according to air-drying methods (under, over) and control group was prepared to manufacturer's instruction. Total 12 groups were evaluated by means of micro tensile bond strength and FE-SEM examination. RESULTS: Degree of evaporation (DE) was increased as time elapsed but different features were observed according to the kind of solvents. Acetone based adhesive showed higher DE than ethanol and butanol based adhesive. Degree of conversion (DC) was increased according to DE except for S3 bond. In microTBS evaluation, bond strength was increased by additional air-drying. Large gaps and droplets were observed in acetone based adhesives by FE-SEM pictures. CONCLUSIONS: Additional air-drying is recommended for single-step self etching adhesive but careful consideration is required for 2-step total etching adhesive because of oxygen inhibition layer. Evaporation method is carefully chose and applied according to the solvent type.

Effect of the exponential curing of composite resin on the microtensile dentin bond strength of adhesives / 대한치과보존학회지

OBJECTIVES: Rapid polymerization of overlying composite resin causes high polymerization shrinkage stress at the adhesive layer. In order to alleviate the shrinkage stress, increasing the light intensity over the first 5 seconds was suggested as an exponential curing mode by an LED light curing unit (Elipar FreeLight2, 3M ESPE). In this study, the effectiveness of the exponential curing mode on reducing stress was evaluated with measuring microtensile bond strength of three adhesives after the overlying composite resin was polymerized with either continuous or exponential curing mode. METHODS: Scotchbond Multipurpose Plus (MP, 3M ESPE), Single Bond 2 (SB, 3M ESPE), and Adper Prompt (AP, 3M ESPE) were applied onto the flat occlusal dentin of extracted human molar. The overlying hybrid composite (Denfil, Vericom, Korea) was cured under one of two exposing modes of the curing unit. At 48h from bonding, microtensile bond strength was measured at a crosshead speed of 1.0 mm/min. The fractured surfaces were observed under FE-SEM. RESULTS: There was no statistically significant difference in the microtensile bond strengths of each adhesive between curing methods (Two-way ANOVA, p > 0.05). The microtensile bond strengths of MP and SB were significantly higher than that of AP (p < 0.05). Mixed failures were observed in most of the fractured surfaces, and differences in the failure mode were not observed among groups. CONCLUSION: The exponential curing method had no beneficial effect on the microtensile dentin bond strengths of three adhesives compared to continuous curing method.

The effect of priming etched dentin with solvent on the microtensile bond strength of hydrophobic dentin adhesive / 대한치과보존학회지

Deterioration of long-term dentin adhesion durability is thought to occur by hydrolytic degradation within hydrophilic domains of the adhesive and hybrid layers. This study investigated the hypothesis that priming the collagen network with an organic solvent displace water without collapse and thereby obtain good bond strength with an adhesive made of hydrophobic monomers and organic solvents. Three experimental adhesives were prepared by dissolving two hydrophobic monomers, bisphenol-A-glycidylmethacrylate (Bis-GMA) and triethyleneglycol dimethacrylate (TEGDMA), into acetone, ethanol or methanol. After an etching and rinsing procedure, the adhesives were applied onto either wet dentin surfaces (wet bonding) or dentin surfaces primed with the same solvent (solvent-primed bonding). Microtensile bond strength (MTBS) was measured at 48 hrs, 1 month and after 10,000 times of thermocycles. The bonded interfaces were evaluated using a scanning electron microscope (SEM). Regardless of bonding protocols, well-developed hybrid layers were observed at the bonded interface in most specimens. The highest mean MTBS was observed in the adhesive containing ethanol at 48 hrs. With solvent-primed bonding, increased MTBS tendencies were seen with thermocycling in the adhesives containing ethanol or methanol. However, in the case of wet bonding, no increase in MTBS was observed with aging.

Class I and Class V composite restorations: Influence of light-curing techniques on microleakage / Restaurações de Classes I e V: influência das técnicas de fotoativação na microinfiltração

Purpose: To evaluate the effect of light-curing techniques on in vitro microleakage of class I and class V composite restorations. Methods: Sixty human premolars were used to prepare 30 class I and 30 class V cavities, which were cleaned and treated with one step self-etching adhesive (Xeno III - Dentsply). A resin composite (TPH 3 - Dentsply) was inserted in two layers and light-cured using two protocols (n=15 each): conventional curing (500 mW/cm ² , 30 s each increment) and pulse delay technique (first increment similar to the conventional technique and the last increment initially cured with 200 mW/cm ² for 3s and after 5 min light-cured again with 500 W/cm² for 30 s). The specimens were polished, submitted to 800 thermal cycles, sealed, and immersed in a 2% basic fuchsin solution. The teeth were cleaned, sliced, and scored according to the dye penetration. Data were analyzed by Mann-Whitney U test. Results: In class I cavities the pulse delay light-curing technique showed statistically significant better sealing than the conventional technique. In class V restorations no difference was detected between the two techniques in enamel and dentin.Conclusion: Light-curing technique affected the microleakage in class I composite restorations but not in class V.

Objetivo: Avaliar o efeito da técnica de fotoativação na microinfiltração in vitro em cavidades de classes I e V restauradas com resina composta. Metodologia: Em 60 pré-molares humanos, foram confeccionadas cavidades de classe I em 30 dentes e de classe V nos demais 30 dentes. As cavidades foram limpas e tratadas com o sistema adesivo autocondicionante de um passo (Xeno III - Dentsply). A resina composta (TPH 3 - Dentsply) foi inserida em dois incrementos e fotoativada de dois modos (n=15 cada): A) Convencional, sendo cada incremento fotoativado com intensidade de 500mW/cm ² por 30 s; B) Pulso tardio, sendo o primeiro incremento fotoativado da mesma forma que o grupo convencional e o último incremento inicialmente fotoativado com 200mW/cm ² , durante 3 s, 5 min de espera e fotoativação final com 500 mW/cm ² por 30 s. Os espécimes foram polidos, submetidos a 800 ciclos térmicos, impermeabilizados e imersos em fucsina básica a 2%. Os dentes foram limpos, seccionados e avaliados quanto à penetração do corante usando-se escores de 0 a 5. Os dados foram analisados por teste U de Mann-Whitney. Resultados: Nas cavidades de classe I houve diferença estatisticamente significativa entre os grupos. Nas cavidades de classe V não houve diferença entre os dois métodos de fotoativação, tanto em margem de esmalte quanto em dentina. Conclusão: Em cavidades de classe I a fotoativação por pulso tardio proporcionou maior vedamento marginal que a fotoativação convencional. Em cavidades de classe V não houve diferença de penetração do corante.

Chemical stability of two dentin single-bottle adhesives as a function of solvent loss / Estabilidade química de dois adesivos dentinários de frasco único em função da perda de solvente

Purpose: Two single-bottle dentin adhesive systems, Single-Bond and Prime and Bond NT, containing ethanol-water or acetone as solvents, respectively, were investigated for their chemical stability regarding solvent loss. Methods: Stability was measured by the adhesive weight changes in accelerated degradation tests under higher room temperature and relative humidity (RH) than normal conditions over 15 days: 25±2ºC / 60±5% RH, 30±2ºC / 65±5% RH, 40±2ºC / 70±5% RH, and 50±2ºC / 75±5% RH. For each temperature the slope and the constant rate for weight loss were recorded to obtain the Arrhenius plot. Water content in Single Bond was determined by K Fisher Titration, and total solvent amount was obtained by subtraction from total weight. Results: The results for Single Bond indicated water content of 5.90±0.08% and alcohol content of 39.14±1.19%. For Prime and Bond NT the acetone percentage was 43.08±1.15%. Weight changes after the accelerated degradation tests revealed that solvent loss in Single-Bond adhesive was lower than in Prime and Bond NT adhesive. Conclusion: The results suggest that chemical stability of adhesives containing ethanolwater is greater than formulations containing acetone.

Objetivo: Dois sistemas adesivos de frasco único, Single-Bond e Prime and Bond NT, contendo etanol-água e acetona como solventes, respectivamente, foram avaliados quanto à sua estabilidade química devido à perda de solvente. Metodologia: A estabilidade foi medida pelas alterações de peso do adesivo em ensaios de degradação acelerada sob condições de temperatura e umidade acima das condições normais ao longo de 15 dias: 25±2ºC / 60±5% RH, 30±2ºC / 65±5% RH, 40±2ºC / 70±5% RH, e 50±2ºC / 75±5% RH. Para cada temperatura, a inclinação e a taxa constante de perda de peso foram registradas para obter o gráfico de Arrhenius. O conteúdo de água no adesivo Single Bond foi determinado por ensaio K Fisher e a quantidade total de solvente foi obtida pela diferença com o peso total. Resultados: Os resultados para Single Bond indicaram conteúdo de 5,90±0,08% de água e 39,14±1,19%de álcool. Para Prime and Bond NT a porcentagem de acetona foi de 43,08±1,15%. As alterações de peso depois dos ensaios de degradação acelerada mostraram que a perda de solvente no adesivo Single-Bond foi menor que no adesivo Prime and Bond NT. Conclusão: Os resultados sugerem que a estabilidade química do adesivo contendo etanolágua é maior que da formulação contendo acetona.

Influence of water storage time on the bond strength of etch-and-rinse and self-etching adhesive systems

The purpose of this study was to evaluate comparatively the shear bond strength (SBS) of etch-and-rinse (Adper Scotch Bond Multi Purpose - ASBMP and Adper Single Bond 2 - ASB2) and self-etching (AdheSe -AD and Adper Prompt - AP) adhesive systems after short- and long-term water storage. Eighty bovine teeth were randomly assigned to 4 groups (n=20, 10 teeth for 24 h and 10 for 6 months). After surface treatment, composite resin cylinders were made with Tetric Ceram using a bisected metallic matrix. The specimens were stored in distilled water at 37°C for either 24 h or 6 months. After these periods, shear strength was assessed in a universal testing machine (0.5 mm/min). Data were submitted to ANOVA and F test at 5 percent significance level. Mean SBSs (MPa) for ASBMP (10.03 ± 3.78) and ASB2 (6.10 ± 2.67) showed no statistically significant differences (p>0.05) between times. The self-etching systems did not differ significantly from each other within the 24-h period, but significant difference was found for AD (1.37 ± 0.64) after 6 months of water storage. In conclusion, the tested etch-and-rinse systems had a better performance in terms of bond durability over time than the self-etching systems.

O objetivo deste estudo foi avaliar, in vitro, a influência do armazenamento em meio degradante a curto e longo prazo sobre os sistemas adesivos: Adper Scotch Bond Multi Purpose (ASBMP); Adper Single Bond 2 (ASB2); AdheSe (AD) e Adper Prompt (AP). Oitenta dentes bovinos foram selecionados e aleatoriamente divididos em 8 grupos (n=10). Após o tratamento da superfície, cilindros de resina composta Tetric Ceram foram confeccionados utilizando uma matriz metálica bipartida. Os espécimes foram armazenados em água destilada a 37°C por 24 h ou 6 meses. Após estes períodos, o teste de cisalhamento foi realizado em uma máquina de ensaio universal (0,5 mm/min). Os resultados em MPa foram submetidos à ANOVA e ao teste F em nível de significância de 5 por cento. O ASBMP (10,03 ± 3,78) e ASB2 (6,10 ± 2,67) não apresentaram diferenças estatisticamente significativas entre os tempos de armazenamento. Os autocondicionantes não diferiram estatisticamente no período de 24 h, mas houve diferença para o AD (1,37 ± 0,64), quando armazenado por 6 meses. Esses adesivos obtiveram valores inferiores nos períodos de avaliação em relação aos convencionais. Os adesivos convencionais mostraram melhor desempenho laboratorial que os autocondicionantes em termos de durabilidade da adesão ao longo do tempo.

A comparative study of shear bond strength of flowable resin associated with dentin adhesive systems with thermocycling effect / 대한치과보철학회지

Statement of problem: Limited research on flowable resin has been undertaken on its application directly on dentin associated with the adhesive systems. Purpose: This study was to evaluate the shear bond strength and fracture aspect of flowable resin on human dentin with various types of dentin bonding adhesives with thermocycling effect. Materials and methods: Filtek-Flow(3M ESPE, USA) was used as flowable resin and Eighty human molars were randomly divided into 4 groups : three dentin bonding adhesives (Scotchbond-Multipurpose: 3-step conventional system, One-Step: One-bottle system, Prompt L-Pop: All-in-one, self-etching primer) and 32% etching treatment without bonding adhesive as a control group. For evaluating their durability of bonding, each group was subdivided : storaging in the water at 37 degree C(24 hours) and thermocycling (0degree C-55degree C, 30 seconds intervals, 1000 cycle). Shear bond strength tests were performed and resin-dentin interface and fracture mode were observed. Results were analysed by one-way ANOVA and Scheffe's multiple range test. Results and Conclusion: 1. At 0 cycle, the mean shear bond strength of One-Step exhibited the highest value of all groups(p0.05). After 1000 thermocycling, One-Step exhibited higher value than other groups(p0.05). 2. The shear bond strength of each group was significantly decreased after thermocycling except Scotchbond-Multipurpose(p>0.05). 3. The most common failure mode was adhesive type and mixed type, next in order.

Comparison of apical seal with or without the use of dentin adhesive system / 대한치과보존학회지

The purpose of this study was to compare the sealing ability of root canal obturation with or without the use of dentin adhesive system. Forty extracted human teeth with one canal were selected and decoronated. The teeth were divided into two Groups. The obturation procedure of Group 1 was the same as that of Group 2 with the exception of dentin adhesive system. Group 2 were obturated with dentin adhesive system, AH-26, and gutta-percha. After obturation, the teeth were immersed in methylene blue solution for 84 hours. The teeth were sectioned horizontally at 1.5 mm (Level 1), 2.0 mm (Level 2), 2.5 mm (Level 3) from the root apex using a low speed microtome. Distance of dye-penetrated surface and total dentinal surface were measured using SigmaScan Pro 5.0, and the ratio of dye-penetrated distance to the total dentinal distance was analyzed statistically by Mann-Whitney U-test. 1. In both groups, the mean leakage ratio was decreased cervically. 2. At level 1, there was no significant difference between group 1 and grpup 2 (p > 0.05). 3. At level 2 and 3, group 1 showed significantly higher mean leakage ratio than group 2 (p < 0.05). The results suggest that using dentin adhesive system in root canal obturation procedure reduces the apical microleakage.

Correlation between Linear polymerization shrinkage & tooth cuspal deflection / 대한치과보존학회지

The purpose of the present study was to evaluate the relationship between the amount of cuspal deflection and linear polymerization shrinkage in resin composite and polyacid modified resin composite. For cuspal defelction and shrinkage measurement, Dyract AP, Compoglass F, Z100, Surefil, Pyramid, Synergy Compact, Heliomolar and Heliomolar HB were used. For measuring polymerization shrinkage, a custom made linometer (R&B, Daejon, Korea) was used. The amount of shrinkage among materials was compared using One-way ANOVA analysis and Tukey's test at the 95% of confidence level. For measuring cuspal deflection of teeth, standardized MOD cavities were prepared in extracted maxillary premolars. After a self-etching adhesive was applied, cavities were bulk filled with one of the filling materials.Fifteen teeth were used for each material. Cuspal deflection was measured by a custom made cuspal-deflection measuring device. One-way ANOVA analysis and Tukey's test were used to determine differences between the materials at the 95% of confidence level. Correlation of polymerization shrinkage and cuspal deflection were analyzed by regression analysis. The amount of polymerization shrinkage from least to greatest was Heliomolar, Surefil < Heliomolar HB < Z100, Synergy Compact < Dyract AP < Pyramid, Compoglass F (p < 0.05). The amount of cuspal deflection from least to greatest was Z100, Heliomolar, Heliomolar HB, Synergy Compact Surefil < Compoglass F < Pyramid, Dyract AP (p < 0.05). The amount of polymerization shrinkage and cuspal deflection showed a correlation (p < 0.001).