Can Application of Universal Primers Alone Be a Substitute for Airborne-Particle Abrasion to Improve Adhesion of Resin Cement to Zirconia?

Purpose: To determine whether universal primers alone can deliver similar levels of adhesion of resin cement to zirconia ceramic when compared to their application in conjunction with airborne-particle abrasion.Materials and Methods: Sintered zirconia blocks (N = 160) (Lava, 3M ESPE), (5.25 x 5.25 x 3 mm(3)) were embedded in acrylic resin, polished, and randomly distributed into 16 groups (n = 10 per group), according to the factors "universal primer" (8 levels) and "air-particle abrasion" (2 levels): 1. ctr: control, without application of a universal primer; 2. AP: Alloy Primer; 3. MP: Monobond Plus; 4. MZP: Metal Zirconia Primer; 5. MZ: MZ Primer; 6. Sg: Signum Zirconia Bond; 7. SbU: Singlebond Universal; 8. ZP: Z Prime Plus. The universal primers were also used after air abrasion (A) of zirconia to form the following 8 groups: Ctr-A, AP-A, MP-A, MZP-A, MZ-A, Sg-A, SbU-A, and ZP-A. After ultrasonic cleaning, air abrasion was performed using Al2O3 particles (110 mu m, 2.5 bar, 20 s at 10 mm) in a chairside air-abrasion device. After ultrasonic cleaning again, universal primers were applied according to each manufacturer's recommendation. The resin cement (RelyX ARC, 3M ESPE) was built up incrementally and photo-polymerized on the zirconia surface using a silicone mold (empty set = 3.5, height = 3 mm). All specimens were stored in distilled water (60 days at 37 degrees C) and then subjected to shear bond strength testing (SBS) in a universal testing machine (1 mm/min). On a separate set of zirconia specimens, contact angle measurements were made using the sessile drop technique with a goniometer after the application of universal primers on control and air-abraded zirconia surfaces. Data (MPa) were analyzed using one-way ANOVA, Tukey's test, and Student's t-test (alpha = 0.05).Results: When universal primers were used alone, SbU presented significantly higher mean SBS (19.5 +/- 5.8) that did the other primers (0 to 9.9 +/- 6.6) (p = 0.001). When air abraded, the groups AP-A (14.1 +/- 6.1), MP-A (15.9 +/- 5.4), ZP-A (16.9 +/- 7.3), SG-A (19.1 +/- 2.1), SbU-A (12 +/- 1.5) showed significant differences (p = 0.03). Adhesive performance of all universal primers was enhanced after air abrasion, with the exception of the SbU and MZ primers. After air abrasion, contact angle measurements were lower for the each primer (without air abrasion: 28.9 to 83.9; with air abrasion: 27.1 to 63.0), except for MZP.Conclusion: Air abrasion with 110 mu m Al2O3 followed by universal primer application increased the bond strength of tested resin cement to zirconia, with the exception of SbU and MZ.

Inlays Made From a Hybrid Material: Adaptation and Bond Strengths

The aim of this study was to evaluate the internal fit, marginal adaptation, and bond strengths of inlays made of computer-aided design/computer-aided manufacturing feldspathic ceramic and polymer-infiltrated ceramic. Twenty molars were randomly selected and prepared to receive inlays that were milled from both materials. Before cementation, internal fit was achieved using the replica technique by molding the internal surface with addition silicone and measuring the cement thicknesses of the pulpal and axial walls. Marginal adaptation was measured on the occlusal and proximal margins of the replica. The inlays were then cemented using resin cement (Panavia F2.0) and subjected to two million thermomechanical cycles in water (200 N load and 3.8-Hz frequency). The restored teeth were then cut into beams, using a lathe, for microtensile testing. The contact angles, marginal integrity, and surface patterns after etching were also observed. Statistical analysis was performed using two-way repeated measures analysis of variance (p<0.05), the Tukey test for internal fit and marginal adaptation, and the Student t-test for bond strength. The failure types (adhesive or cohesive) were classified on each fractured beam. The results showed that the misfit of the pulpal walls (p=0.0002) and the marginal adaptation (p=0.0001) of the feldspathic ceramic were significantly higher when compared to those of the polymer-infiltrated ceramic, while the bond strength values of the former were higher when compared to those of the latter. The contact angle of the polymer-infiltrated ceramic was also higher. In the present study, the hybrid ceramic presented improved internal and marginal adaptation, but the bond strengths were higher for the feldspathic ceramic.

Benzilaminopurina e ácido naftaleno acético na indução e multiplicação in vitro de gemas de abacaxizeiro da cultivar 'IAC Gomo-de-mel'

O objetivo deste trabalho foi avaliar os efeitos de BAP (6-benzilaminopurina) e NAA (ácido naftaleno acético) na indução, na multiplicação in vitro de gemas, nas brotações de Ananas comosus da cultivar 'IAC Gomo-de-mel' e a correlação desses efeitos com a atividade de peroxidase e o teor de proteína solúvel total. Foram utilizadas gemas axilares retiradas da coroa de frutos sadios, inoculadas em tubo de ensaio contendo meio de cultura MS solidificado com ágar a 5%, pH ajustado para 5,7, contendo os tratamentos que incluíam diferentes concentrações e combinações de BAP (0, 0,5, 1,0 e 1,5mg L-1) e NAA (0, 0,5 e 1,0mg L-1). Nessa fase, aos 65 dias, ocorreu a formação de 2,24 brotações, utilizando-se 1mg L-1 de BAP. Após o desenvolvimento, as gemas foram inoculadas em meio MS líquido associado a dois tratamentos (1,0mg L-1 BAP + 0,5mg L-1 NAA e 1,0mg L-1 BAP + 1,0mg L-1 NAA) e, aos 95 dias, o meio de cultura mais adequado foi aquele que continha 1,0mg L-1 BAP + 0,5mg L-1 NAA, proporcionando 7,42 brotações, menor porcentagem de hiper-hidricidade, maior número de brotações e indução de gemas. As proteínas solúveis apresentaram relação negativa com hiper-hidricidade e comprimento de brotações. A atividade da peroxidase foi maior em plantas com maior número de brotos e com maior porcentagem de hiper-hidricidade.

Preanesthetic assessment data do not influence the time for tracheal intubation with Airtraq (TM) video laryngoscope in obese patients

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)