Influence of Er:YAG laser irradiation settings on dentin-adhesive interfacial ultramorphology and dentin bond strength.

This study evaluated the effects of Erbium-doped yttrium aluminium garnet (Er:YAG) laser settings and dentin bonding agents on ultramorphological characteristics of resin-laser-irradiated dentin interfaces and dentin bond strength (BS) of these adhesive systems. Additionally, dentin depth affected by Er:YAG laser irradiations was measured. The experiments were performed on occlusal dentin surfaces of third molars that were flattened with 600-grit SiC sandpaper. Treated-dentin with laser settings (250 mJ/4 Hz and 160 mJ/10 Hz) were the experimental groups, while SiC abraded dentin was the control. These three dentin treatments and three adhesives (two self-etchings and one etch-&-rinse adhesive) formed nine groups for the ultramorphology of laser-ablated dentin-adhesives interfacial analysis, using a transmission electron microscope (TEM). For BS (n = 8), the same nine groups were tested with addition of the two evaluation times (24 h after sample preparation or 1 year). The depths of Er:YAG laser effects into the dentin were measured using a TEM (n = 10). Ablated-dentin depth and BS data were analyzed by one- and three-way ANOVA, respectively, and Tukey's test (α = 0.05). Hybrid layer formation was only observed for controls, while for laser-treated dentin, adhesives were bonded to dentin with resin tags formation. Laser settings reduced the BS for all adhesives at 24 h, while at 1 year, etch-&-rinse adhesive presented the highest BS, regardless treatment (control or laser settings). Dentin depth affected by laser settings was similar. The laser irradiation altered the bonding mechanism of the adhesives to dentin and reduced the BS for self-etching adhesives. Etch-&-rinse adhesive yielded the highest BS at 1 year. Laser settings similarly affected the dentin in depth. HIGHLIGHTS: Er:YAG laser irradiation settings produced similar effects on depth and bond strength to dentin. The etch-&-rinse adhesive yielded the highest dentin bond strength regardless of the type of dentin treatment at 1 year.

Adhesion of multimode adhesives to enamel and dentin after one year of water storage.

OBJECTIVES: This study aimed to evaluate the ultramorphological characteristics of tooth-resin interfaces and the bond strength (BS) of multimode adhesive systems to enamel and dentin. METHODS: Multimode adhesives (Scotchbond Universal (SBU) and All-Bond Universal) were tested in both self-etch and etch-and-rinse modes and compared to control groups (Optibond FL and Clearfil SE Bond (CSB)). Adhesives were applied to human molars and composite blocks were incrementally built up. Teeth were sectioned to obtain specimens for microtensile BS and TEM analysis. Specimens were tested after storage for either 24 h or 1 year. SEM analyses were performed to classify the failure pattern of beam specimens after BS testing. RESULTS: Etching increased the enamel BS of multimode adhesives; however, BS decreased after storage for 1 year. No significant differences in dentin BS were noted between multimode and control in either evaluation period. Storage for 1 year only reduced the dentin BS for SBU in self-etch mode. TEM analysis identified hybridization and interaction zones in dentin and enamel for all adhesives. Silver impregnation was detected on dentin-resin interfaces after storage of specimens for 1 year only with the SBU and CSB. CONCLUSIONS: Storage for 1 year reduced enamel BS when adhesives are applied on etched surface; however, BS of multimode adhesives did not differ from those of the control group. In dentin, no significant difference was noted between the multimode and control group adhesives, regardless of etching mode. CLINICAL RELEVANCE: In general, multimode adhesives showed similar behavior when compared to traditional adhesive techniques. Multimode adhesives are one-step self-etching adhesives that can also be used after enamel/dentin phosphoric acid etching, but each product may work better in specific conditions.

Influence of resin coating on bond strength of self-adhesive resin cements to dentin.

This study evaluated the effect of resin coating (COA) on dentin bond strength (BS) of five resin cements (RC). Ten groups were tested, according to RC and COA combinations. RCs were applied onto prepolymerized resin discs, which were bonded to dentin surfaces. Teeth were stored in water for 24 h, subjected to 5,000 thermocycles and sectioned to obtain beams, which were tested in tension. The COA increased the BS for Panavia F2.0, RelyX Unicem, and RelyX Unicem 2, whereas no changes in BS were observed for two other RCs; Clearfil SA Cement, which showed the lowest BS among groups with COA and G-Cem, which showed the highest BS among RCs without COA. COA can increase the BS of RC depending on the type of RC.

Self-etch adhesive systems: a literature review.

This paper presents the state of the art of self-etch adhesive systems. Four topics are shown in this review and included: the historic of this category of bonding agents, bonding mechanism, characteristics/properties and the formation of acid-base resistant zone at enamel/dentin-adhesive interfaces. Also, advantages regarding etch-and-rinse systems and classifications of self-etch adhesive systems according to the number of steps and acidity are addressed. Finally, issues like the potential durability and clinical importance are discussed. Self-etch adhesive systems are promising materials because they are easy to use, bond chemically to tooth structure and maintain the dentin hydroxyapatite, which is important for the durability of the bonding.

Self-Etch Adhesive Systems: A Literature Review

This paper presents the state of the art of self-etch adhesive systems. Four topics are shown in this review and included: the historic of this category of bonding agents, bonding mechanism, characteristics/properties and the formation of acid-base resistant zone at enamel/dentin-adhesive interfaces. Also, advantages regarding etch-and-rinse systems and classifications of self-etch adhesive systems according to the number of steps and acidity are addressed. Finally, issues like the potential durability and clinical importance are discussed. Self-etch adhesive systems are promising materials because they are easy to use, bond chemically to tooth structure and maintain the dentin hydroxyapatite, which is important for the durability of the bonding.

Este artigo apresenta o estado da arte de sistemas adesivos autocondicionantes. Quatro temas são apresentados nesta revisão: o histórico desta categoria de agentes de união, o mecanismo de adesão, as características/propriedades, e a formação da zona ácido-base resistente nas interfaces esmalte/dentina-adesivo. Além disso, as vantagens relativas aos sistemas de condicionamento total ( etch-and-rinse ) e as classificações dos sistemas adesivos autocondicionantes de acordo com o número de passos e acidez são abordados. Por fim, são discutidas questões como a durabilidade potencial e a importância clínica. Sistemas adesivos autocondicionantes são materiais promissores porque são fáceis de usar, unem-se quimicamente à estrutura do dente e preservam a hidroxiapatita dentinária, o que é importante para a durabilidade da ligação.

Enamel and dentin bond strength, interfacial ultramorphology and fluoride ion release of self-etching adhesives during a pH-cycling regime.

PURPOSE: This study evaluated the effects of pH cycling on fluoride release and bond strength of two self-etching adhesive systems to both enamel and dentin. The ultramorphology of the interfaces produced by the adhesive systems were also analyzed. MATERIALS AND METHODS: The buccal surfaces of bovine incisors were flattened to expose enamel and dentin, which were bonded with either Clearfil Protect Bond (CPB) or One-Up Bond F Plus (OBP). The bonded samples were prepared for microtensile bond strength (µTBS) testing, fluoride ion release, and transmission electron microscopy. pH cycling comprised demineralization (8 h/day) and remineralization (16 h/day) cycles for 8 days. The µTBS data were analyzed by two-way ANOVA, while fluoride release was analyzed using the Friedman and Wilcoxon tests. RESULTS: The adhesives presented similar bond strengths to enamel. However, the dentin bond strength of CPB was higher than that of OBP. pH cycling did not influence enamel or dentin µTBS. The amount of fluoride released from the bonded enamel and dentin was low and varied among the groups. The morphological evaluation showed that the thickness of the dentin hybrid layers was similar for both adhesives. CONCLUSION: The pH-cycling regime did not affect enamel or dentin bond strengths. In enamel, both the self-etching adhesives tested presented similar bond strengths, but in dentin, Clearfil Protect Bond showed higher dentin bonding than One-Up Bond F Plus.

Interfacial ultramorphology evaluation of resin luting cements to dentin: a correlative scanning electron microscopy and transmission electron microscopy analysis.

The objective of this study was to analyze the dentin-resin cements interfacial ultramorphologies using two different methods: scanning (SEM) and transmission electron microscopy (TEM). Four commercial products were evaluated: two conventional cementing system (RelyX ARC/Adper™ Scotchbond™ Multi-Purpose Plus, 3M ESPE and Clearfil Esthetic Cement/DC Bond, Kuraray) and two self-adhesive resin cements (RelyX Unicem, 3M ESPE and Clearfil SA Cement, Kuraray). Prepolymerized resin disks (Sinfony, 3M ESPE) were cemented on oclusal dentin surfaces of 24 third human molars, simulating the indirect restorations. After 24 h, teeth were sectioned into 0.9-mm thick slabs and processed for microscopy analyses (SEM or TEM/ n = 3). Qualitative characterization of dentin-resin cement interface was performed. Hybrid layer formation with long and dense resin tags was observed only for RelyX ARC cementing system. Clearfil Esthetic Cement/DC Bond system revealed few and short resin tags formation, whereas no hybridization and resin tags were detected for self-adhesive resin cements. Some interfacial regions exhibited that the self-adhesive resin cements were not bonded to dentin, presenting bubbles or voids at the interfaces. In conclusion, TEM and SEM bonding interface analyses showed ultramorphological variations among resin cements, which are directly related to dental bonding strategies used for each resin cement tested.

Avaliação da resistência de união adesivo-dentina - Efeito do armazenamento em saliva artificial / Bond strength evaluation of adhesive-dentin - Effect of artificial saliva storage

Introdução - Os sistemas adesivos têm evoluído e a durabilidade da união resina-dentina é um assunto importante na Odontologia Restauradora, uma vez que está diretamente relacionada com a longevidade dos procedimentos restauradores. Este estudo avaliou o efeito do tempo de armazenamento em saliva artificial na resistência de união de 4 adesivos à dentina. Material e Métodos - Vinte terceiros molares foram utilizados e divididos em 4 grupos (n=5), que corresponderam aos adesivos testados: Adper Easy Bond (EB), AdperSE Plus (SP), Adper Single Bond 2 (SB) e Clearfil SE Bond (CS). Os adesivos foram aplicados na dentina oclusal planificada e em seguida, os dentes foram restaurados com incrementos de 2 mm de resina composta. Após armazenamento em água destilada por 24 horas, os dentes restaurados foram seccionados seguindo a metodologia de microtração. Metade dos espécimes obtidos de cada dente foi armazenada em saliva artificial a 37°C por 6 meses (6ME) e a outra metade (24H) submetida ao teste de microtração. Os dados foram analisados pela ANOVA (2 fatores) e teste de Tukey (p<0,05). Resultados - Os adesivos produziram similar resistência de união à dentina nos dois tempos avaliados (p=0,7860). A resistência de união de união dos adesivos não apresentou diferença significativa entre os tempos avaliados (p=0,8454). As médias de resistência de união (DP) para os adesivos foram (MPa): EB(24H): 57,8(17,4), EB(6ME): 57,7(18,5), SP(24H): 57,9(15,5), SP(6ME): 55,9(9,6), SB(24H): 48,9(8,1), SB(6ME): 49,7(7,9), CS(24H): 60,1(21,0) e CS(6ME): 59,0(9,5). Conclusão - A resistência da união adesivo-dentina não foi afetada pelo tempo do armazenamento.

Introduction – The adhesive systems have improved and the resin-dentin bond durability is an important subject within Restorative Dentistry, since it is related to longevity of composite restorations. This study evaluated the effect of artificial saliva storage on bond strength of 4 adhesives to dentin. Material and Methods - Twenty third molars were used in this study. They were divided into 4 groups (n=5), which corresponded to adhesives tested: Adper Easy Bond (EB), Adper SE Plus (SP), Adper Single Bond 2 (SB) and Clearfil SE Bond (CS). Bonding agents were applied to flat oclusal dentin surface and the teethwere incrementally restored with composite resin. After 24 hours of water storage, the restored teeth were sectioned according to the micro-tensile bond methodology. The half of bonded beam specimens were stored in artificial saliva at 37 oC for 6 months (6ME) andthe other half (24H) was tested in tension. Data were analyzed by two-way ANOVA and Tukey test (p<0.05). Results - The results suggested that the adhesives present similar bond strength mean values to dentin in both evaluation times. (p=0.7860). The bond strengthof adhesive systems was not different between the evaluation times (p=0.8454). The bond strength means (DP) for the adhesives were (MPa): EB(24H): 57.8(17.4), EB(6ME): 57.7(18.5), SP(24H): 57.9(15.5), SP(6ME): 55.9(9.6), SB(24H): 48.9(8.1), SB(6ME): 49.7(7.9), CS(24H): 60.1(21.0) and CS(6ME): 59.0(9.5). Conclusion - The resin-dentinbond strength of the adhesives tested was not affect by storage.

Adesivos autocondicionantes: uma realidade clínica / Self-etching adhesive systems: a clinical fact

No estudo da evolução dos sistemas adesivos autocondicionantes, observa-se que os avanços mais significativos foram obtidos a partir de 1994, com o desenvolvimento de adesivos à base de fenil-P, como monômero ácido. Os adesivos autocondicionantes podem ser classificados de acordo com a acidez do adesivo/monômero e os números de etapas clínicas para sua aplicação. Nessa técnica adesiva, não existe a remoção do ácido fosfórico com jatos de água e, portanto, nenhum controle de umidade pós-condicionamento ácido é necessário. Monômeros-ácidos derivados do ácido fosfórico e carboxílico são responsáveis pelo condicionamento e infiltração no esmalte e dentina. Outras vantagens podem ser obtidas, como a redução da sensibilidade pós-operatória e simplificação das etapas de aplicação do adesivo. Os adesivos de "dois passos", que apresentam um primer-autocondicionante e aplicação de uma camada de resina hidrofóbica sobre a superfície tratada com o primer, têm sido considerados os melhores sistemas, quando comparados aos adesivos autocondicionantes de um passo clínico.

Effects of the solvent evaporation technique on the degree of conversion of one-bottle adhesive systems.

This study evaluated the effect of four methods of solvent evaporation on the degree of conversion (DC) of seven one-bottle adhesive systems: Excite (EX), ONE-STEP (OS), Optibond Solo Plus (OB), Prime&Bond 2.1 (PB), Prime&Bond NT (NT), Single Bond (SB) and Single Bond Plus (SP) using Fourier Transform Infrared Analysis (FTIR). Adhesive resins were: 1) applied to KBr pellet surfaces and left undisturbed for 30 seconds (condition 1), 2) left undisturbed for 30 seconds and air-dried with an air stream for 10 seconds (condition 2), 3) left undisturbed for 60 seconds (condition 3) and 4) left undisturbed for 60 seconds and air-dried for 10 seconds (condition 4) before curing. FTIR spectra were obtained and the DC was calculated by comparing the ratio of aliphatic/aromatic double carbon bonds before and after light-activation for 10 seconds (XL 3000, 3M). The results of each product were analyzed by one-way repeated measure ANOVA and post-hoc Tukey's test (p<0.05). The DC of PB, NT, OB and SP adhesives was not affected by the four evaporation conditions, while the DC of EX, OS and SB changed according to the evaporation method. The results suggested that the DC of some adhesives was similar regardless of the evaporation method when no water from dentin or rinsing was involved. Other bonding agents showed higher DC after specific conditions of solvent evaporation.