Mini-interfacial Fracture Toughness of a Multimode Adhesive Bonded to Plasma-treated Dentin.

PURPOSE: To investigate the bonding efficacy of a multimode adhesive to plasma-treated and -untreated (control) dentin using a mini-interfacial fracture toughness (mini-iFT) test. MATERIALS AND METHODS: Twenty human molars were used in a split-tooth design (n = 10). The adhesive Scotchbond Universal (SBU; 3M ESPE) was applied in etch-and-rinse (E&R) and self-etch (SE) modes. Mid-coronal dentin was exposed and covered with a standardized smear layer ground to 320 grit. One half of each dentin surface received 15 s of non-thermal atmospheric plasma (NTAP), while the other half was covered with a metallic barrier and kept untreated. Following the E&R mode, dentin was plasma treated immediately after phosphoric acid etching. SBU and a resin-based composite were applied to dentin following the manufacturer's instructions. Six mini-iFT specimens were prepared per tooth (1.5 x 2.0 x 16 to 18 mm), and a single notch was prepared at the adhesive-dentin interface using a 150-µm diamond blade under water cooling. Half of the mini-iFT specimens were immediately loaded until failure in a 4-point bending test, while the other half were first stored in distilled water for 6 months. After testing, the exact dimensions of the notch were measured with a measuring optical microscope, from which ΚIc was determined. RESULTS: Three-way ANOVA revealed higher mini-iFT for SBU applied in E&R than SE mode for both storage times, irrespective of NTAP treatment. CONCLUSION: Overall, mini-iFT did not decrease for any of the experimental groups upon 6-month aging, while plasma treatment did not show a direct beneficial effect on mini-iFT of SBU applied in either E&R or SE mode.

Effect of Silanization on Microtensile Bond Strength of Different Resin Cements to a Lithium Disilicate Glass Ceramic.

AIM: This study evaluated the influence of a silane-coupling agent on the bond strength of a self-adhesive cement and a conventional resin cement to a lithium disilicate glass ceramic. MATERIALS AND METHODS: A total of eight ceramic blocks were fabricated and divided into four groups (n = 2). In groups 1 and 3, ceramic surfaces were etched with hydrofluoric acid 10% for 20 seconds, rinsed for 30 seconds, and air-dried. One layer of a silane agent was applied onto all ceramic specimens and air-dried for 30 seconds. In groups 2 and 4, ceramic surfaces were etched with hydrofluoric acid, rinsed, and air-dried without application of the silane-coupling agent. The ceramic blocks were bonded to a block of composite with a self-adhesive resin cement or with a conventional resin cement, according to the manufacturer's instructions. After 24 hours in distilled water at 37°C, the specimens were sectioned perpendicular to the bonding interface area to obtain beams with a bonding area of 0.8 mm(2) and submitted to a microtensile bond strength test at a crosshead speed of 0.5 mm/min. Data were statistically analyzed with one-way analysis of variance and the Games-Howell post hoc test (p = 0.05). Fractured specimens were examined under optical microscopy at 40x magnification. RESULTS: Silanization resulted in higher microtensile bond strength compared to groups without silane. No significant differences were found between the conventional resin cement and the self-adhesive resin cement with silane agent (p = 0.983), and without silane agent (p = 0.877). CONCLUSION: Silanization appears to be crucial for resin bonding to a lithium disilicate-based ceramic, regardless of the resin cement used. The self-adhesive resin cement performed as well as the conventional resin cement. CLINICAL SIGNIFICANCE: Applying one layer of a silane-coupling agent after etching the ceramic surface with hydrofluoric acid 10% enhanced the bond strength between resin cements and a glass ceramic.

Compósitos em incisivos lateriais conoides: ciência e arte / Composite resin restorations in peg-shaped lateral incisors: science and art

A presença de incisivos laterais conoides compromete a harmonia do sorriso. O presente artigo tem como objetivo apresentar um relato de caso de reanatomização de laterais conoides, com consequente fechamento dos diastemas anterossuperiores e restabelecimento de guia canina. Entre as opções de tratamento optou-se pela restauração direta com resina composta por apresentar-se como o método que melhor se adaptou às expectativas e anseios da paciente. Ao final, o processo resultou em um sorriso esteticamente agradável não somente em termos dentais, mas também com relação à face da paciente, proporcionando um aspecto harmonioso e natural ao sorriso...

Diastema and peg-shaped teeth may compromise patient’s smile harmony. This article presents a case report of reshaping peg-shaped lateral incisors and subsequent closure of the maxillary anterior spacing and reestablishment of the canine guidance. Among the treatment options, direct resin composite restoration was selected because it was the treatment that best adapted to the expectations and desires of the patient. An excellent result was achieved with an aesthetically pleasing smile not only in dental terms, but also in relation to the face of the patient...

Microtensile bond strength of a universal adhesive to deepdentin / Resistência de união de um sistema adesivo universal aplicado em dentina profunda

This study evaluated the microtensile bond strength of a universal adhesive system applied to deep dentin under different bonding strategies.Material and Methods: Fifteen human third molar shad the coronal portion removed exposing deep dentin and were assigned into 3 groups according to the adhesive system: G1(control): 2-steps totaletch(Adper Single Bond 2, 3M ESPE); G2: 1-stepself-etch universal adhesive (Scotchbond Universal,3M ESPE); G3:2 steps total-etch universal adhesive(Scotchbond Universal, 3M ESPE). Composite build up swere performed on the dentin surfaces and after water storage for 24 h, teeth were sectioned to obtain40 bonded beams per group with sectional areaof 0.9 mm2. The specimens were submitted to the microtensile bond strength (μTBS) test until failure.Statistical analyses were computed using one-wayANOVA (p = 0.05). Results: The mean μTBS (inMPa) were G1 = 22.27, G2 = 22.85 and G3 = 20.3.After statistical analysis, no significant differences were observed among the groups. Conclusions:Universal adhesive system performed similarly tothe total-etch adhesive and was not affected by theadhesion strategy...

O estudo avaliou a resistência de união à microtração de um sistema adesivo universal aplicado em dentina profunda sob diferentes estratégias adesivas. Material e Métodos: 15 terceiros molares tiveram a porção coronária removida,expondo dentina profunda, sendo então divididos em 3 grupos de acordo com o sistema adesivo: G1 (controle) sistema adesivo convencional de 2 passos e condicionamento ácido total (Adper SingleBond 2, 3M ESPE); G2: sistema adesivo universal,1 passo, autocondicionante (Scotchbond Universal,3M ESPE); G3: sistema adesivo universal, 2 passos e condicionamento ácido total (Scotchbond Universal,3M ESPE). As porções coronárias foram reconstruídas em resina composta e após 24 h em água destilada os espécimes foram seccionados para obtenção de 40 filetes por grupo. Os filetes foram submetidos ao teste de microtração à velocidade de 0,5 mm/min e os dados analisados estatisticamente. Results:Não foram observadas diferenças estatísticas entre os grupos, sendo as médias de resistência de união(MPa): G1 = 22,27, G2 = 22,85 and G3 = 20,3.Conclusão: O sistema adesivo universal apresentou performance similar ao sistema adesivo convencional e seu desempenho não foi afetado pela estratégia adesiva utilizada...

Silanization effect on microtensile bond strength of a self-adhesive luting material to a disilicate-based glass ceramic

Introduction: The rehabilitation of teeth by means of ceramic indirect restorations has been widely performed. Previous studies has shown the effectiveness of silane coupling agents on improving the bond strength of the adhesion of resin cements to ceramics; however, some studies question the use of silane. Objective: To evaluate the effect of silane application on the microtensile bond strength of an auto-adhesive luting material to a lithium disilicate glass-ceramic. Material and methods: Two blocks (9x11x4mm) of lithium disilicate glass-ceramic had one of their surfaces polished (# 220, 360, 600 grit silicon-carbide abrasive papers) and cleaned ultrasonically. The ceramic blocks were then divided into two groups according to the surface treatment: G1 (control group): etched with 10% hydrofluoric acid for 20s and silane coated; G2: etched with 10% hydrofluoric acid for 20s. After building two blocks of composite resin (Filtek Z350) with the same dimensions of the ceramic blocks, the self-adhesive resin cement (SpeedCEM) was applied directly to the ceramic surface and the resin block was seated on the cement. After storage (24h, 37°C), the ceramic-cement-composite blocks were cut with an Isomet low-speed diamond saw machine producing sticks, which were loaded to failure at a crosshead speed of 0.5 mm/min. The type of fracture was analyzed under an optical microscope. The results were statistically analyzed using the Student t test. Results: The mean microtensile and standard deviations in megaPascals were: G1 = 21.32 (± 4.36) and G2 = 16.55 (± 4.92). Statistical analysis showed that the bond strength was not significantly affected by the surface treatment with silane. Most of the fractures occurred within the adhesion zone. Conclusion: The application of silane had no significant effect on the bond strength between lithium disilicate glass-ceramic and self-adhesive resin cement.