Effectiveness of different orthodontic adhesives and a universal bonding resin on the bond strength of brackets to different ceramics / Eficácia de diferentes adesivos ortodônticos e uma resina de ligação universal na resistência adesiva de bráquetes à diferentes cerâmicas

Objective: The aim of this study was to evaluate the effectiveness of different adhesives on the shear bond strength (SBS) of brackets bonded to different ceramic materials. Material and Methods: Fifty disk-shaped specimens were produced from lithium disilicate (IPS e.max CAD) and monolithic zirconia (Cercon) materials. Each specimen was polished with a three-step diamond polishing system. The polished ceramic surfaces were conditioned with universal bonding resin (Assure Plus) without pre-treatment, except for two specimens. Central brackets were bonded onto different ceramic specimens with different adhesives as follows: group 1: conventional adhesive onto the lithium disilicate; group 2: one-step adhesive onto the lithium disilicate; group 3: conventional adhesive onto the monolithic zirconia; group 4: one-step adhesive onto the monolithic zirconia. After thermal cycling, the specimens were subjected to the SBS test. The adhesive remnant index (ARI) scores were also recorded to evaluate bond failure type. Kruskal­Wallis and Mann-Whitney U tests were used for statistical analysis. Results: There were statistically significant differences among the SBS values (p˂0.05). The monolithic zirconia group with universal bonding resin and conventional orthodontic adhesive demonstrated the highest SBS value (6.34 MPa) and ARI scores. The lithium disilicate group showed the lowest SBS value (2.17 MPa) with the same protocol. No adhesive remained on the lithium disilicate specimens. Conclusion: One-step adhesive and universal bonding resin combination should not be considered as an alternative for lithium disilicate and monolithic zirconia restorations. Conventional adhesive and universal bonding resin application can be effective on non-pretreated ceramic surfaces during orthodontic bonding (AU)

Objetivo: o objetivo deste estudo foi avaliar a eficácia de diferentes adesivos na resistência ao cisalhamento (SBS) de bráquetes colados a diferentes materiais cerâmicos. Material e métodos: Cinquenta espécimes em forma de disco foram produzidos a partir de materiais de dissilicato de lítio (IPS e.max CAD) e zircônia monolítica (Cercon). Cada amostra foi polida com um sistema de polimento de diamante de três passos. As superfícies cerâmicas polidas foram condicionadas com resina de ligação universal (Assure Plus) sem pré-tratamento, exceto para dois corpos-de-prova. Bráquetes centrais foram colados em diferentes corpos de prova cerâmicos com diferentes adesivos da seguinte forma: grupo 1: adesivo convencional sobre dissilicato de lítio; grupo 2: adesivo de uma etapa sobre o dissilicato de lítio; grupo 3: adesivo convencional sobre zircônia monolítica; grupo 4: adesivo de uma etapa sobre a zircônia monolítica. Após a ciclagem térmica, os corpos-de-prova foram submetidos ao teste SBS. Os escores do índice de remanescente adesivo (ARI) também foram registrados para avaliar o tipo de falha de adesão. Os testes U de Kruskal-Wallis e Mann-Whitney foram usados para análise estatística. Resultados: Houve diferenças estatisticamente significativas entre os valores de SBS (p˂0,05). O grupo de zircônia monolítica com resina de colagem universal e adesivo ortodôntico convencional demonstrou o maior valor de SBS (6,34 MPa) e escores de ARI. O grupo de dissilicato de lítio apresentou o menor valor de SBS (2,17 MPa) com o mesmo protocolo. Nenhum adesivo permaneceu nas amostras de dissilicato de lítio. Conclusão: A combinação de adesivo de uma etapa e resina de ligação universal não deve ser considerada como uma alternativa para restaurações de dissilicato de lítio e zircônia monolítica. A aplicação de adesivo convencional e resina de colagem universal podem ser eficazes em superfícies de cerâmica não pré-tratadas durante a colagem ortodôntica (AU)

Influence of rebonding procedures on microleakage of composite resin restorations / 대한치과보존학회지

During a composite resin restoration, an anticipating contraction gap is usually tried to seal with low-viscosity resin after successive polishing, etching, rinsing and drying steps, which as a whole is called rebonding procedure. However, the gap might already have been filled with water or debris before applying the sealing resin. We hypothesized that microleakage would decrease if the rebonding agent was applied before the polishing step, i.e., immediately after curing composite resin. On the buccal and lingual surfaces of 35 extracted human molar teeth, class V cavities were prepared withthe occlusal margin in enamel and the gingival margin in dentin. They were restored with a hybrid composite resin Z250 (3M ESPE, USA) using an adhesive AdperTM Single Bond 2 (3M ESPE). As rebonding agents, BisCover LV (Bisco, USA), ScotchBond Multi-Purpose adhesive (3M ESPE) and an experimental adhesive were applied on the restoration margins before polishing step or after successive polishing and etching steps. The infiltration depth of 2% methylene blue into the margin was measured using an optical stereomicroscope. The correlation between viscosity of rebonding agents and mciroleakage was also evaluated. There were no statistically significant differences in the microleakage within the rebonding procedures, within the rebonding agents, and within the margins. However, when the restorations were not rebonded, the microleakage at gingival margin was significantly higher than those groups rebonded with 3 agents (p < 0.05). The difference was not observed at the occlusal margin. No significant correlation was found between viscosity of rebonding agents and microleakage, except very weak correlation in case of rebonding after polishing and etching at gingival margin (r = -0.326, p = 0.041).

Effect of an intermediate bonding resin and flowable resin on the compatibility of two-step total etching adhesives with a self-curing composite resin / 대한치과보존학회지

This study compared the effect of an activator, intermediate bonding resin and low-viscosity flowable resin on the microtensile bond strength of a self-curing composite resin used with two-step total etching adhesives. Twenty extracted permanent molars were used. The teeth were assigned randomly to nine groups (n=10) according to the adhesive system and application of additional methods (activator, intermediate adhesive, flowable resin). The bonding agents and additional applications of each group were applied to the dentin surfaces. Self-curing composite resin buildups were made for each tooth to form a core, 5mm in height. The restored teeth were then stored in distilled water at room temperature for 24h before sectioning. The microtensile bond strength of all specimens was examined. The data was analyzed statistically by one-way ANOVA and a Scheffe's test. The application of an intermediate bonding resin (Optibond FL adhesive) and low-viscosity flowable resin (Tetric N-flow) produced higher bond strength than that with the activator in all groups. Regardless of the method selected, Optibond solo plus produced the lowest microTBS to dentin. The failure modes of the tested dentin bonding agents were mostly adhesive failure but there were some cases showed cohesive failure in the resin.

The effect of bonding resin on bond strength of dual-cure resin cements / 대한치과보존학회지

The objective of this study is to evaluate the effect of an additional application of bonding resin on the bond strength of resin luting cements in both the light-cure (LC) and self-cure (SC) modes by means of the microTBS tests. Three combinations of One-Step Plus with Choice, Single Bond with Rely X ARC, and One-Up Bond F with Bistite II were used. D/E resin and Pre-Bond resin were used for the additional application. Twelve experimental groups were made. Three mandibular 3rd molars were used in each group. Indirect composite blocks were cemented on the tooth surface. 1 x 1 mm2 dentin-composite beam for microTBS testing were made and tested. When total-etching dentin adhesives were used, an additional application of the bonding resin increased the bond strength (P 0.05). In conclusion, the results suggest that an additional application of the bonding resin increases bond strength and enhances quality of bonding when using total-etching dentin adhesives.

Self-adhesion of low-viscosity composites to dentin surface / 대한치과보존학회지

The objectiveness of this study was to evaluate whether low-viscosity composite can bond effectively to dentin surface without bonding resin. The low-viscosity composites being 50wt% filler content were made by the inclusion of bonding resin of two self-etching systems(Clearfil SE Bond, Unifil Bond) varied with contents as 0, 10, 20, 30, 40, 50wt%. Exposed dentin surfaces of extracted 3rd molars are used. Dentin bond strengths were measured. The tests were carried out with a micro-shear device placed testing machine at a CHS of 1mm/min after a low-viscosity composite was filled into an iris cut from micro tygon tubing with internal diameter approximately 0.8mm and height of 1.0mm. 1. Flexural strength and modulus was increased with the addition of bonding resin. 2. Micro-shear bond strength to dentin was improved according to content of bonding resin irrespective of applying or not bonding resin in bonding procedure, and that of Clearfil SE Bond groups was higher than Unifil Bond. 3. There were no significant difference whether use of each bonding resin in bonding procedure for S-40, S-50, U-50(p>0.05). 4. In SEM examination, resin was well infiltrated into dentin after primed with self-etching primer only for S-50 and U-50 in spite of the formation of thinner hybrid layer. Low viscosity composite including some functional monomer may be used as dentin bonding resin without an intermediary bonding agent. It makes a simplified bonding procedure and foresees the possibility of self-adhesive restorative material.