Validation of cone-beam computed tomography and magnetic resonance imaging of the porcine spine: a comparative study with multidetector computed tomography and anatomical specimens

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

A method for chromosome preparations from large fish specimens using in vitro short-term treatment with colchicine

This paper describes a new technique for preparing mitotic fish chromosomes using short-term in vitro treatment with colchicine. The results show that a large number of good quality metaphases (many suitable for chromosome banding) can be obtained by this technique, which requires an average of 1 h and 30 min for all steps. The procedure considerably reduces the time normally required for chromosome preparations in fish.

Dentin bond strength: influence of Er:YAG and Nd:YAG lasers

The aim of this study was to investigate the effects of Er:YAG and Nd:YAG lasers on the shear bond strength of composite resin to dentin. The coronal portion of 56 human molars was divided into three parts, and the dentin thickness was standardized at 2 mm. A 3-mm hole was marked in the center of each tooth with sealing tape paper. The specimens (n = 14) were then divided into four groups: (1) acid etching + Single Bond (SB) (control), (2) acid etching + SB + Nd:YAG laser irradiation (before adhesive curing), (3) thermal etching with the Er:YAG laser + SB, and (4) thermal etching with the Er:YAG laser + SB + Nd:YAG laser irradiation (before adhesive curing). A composite resin cylinder was built into the delimited area for conducting the shear bond strength test on the universal testing machine. The means ± standard deviations were: group 1, 17.05 ± 4.15 MPa; group 2, 16.90 ± 3.36 MPa; group 3, 12.12 ± 3.85 MPa; and group 4, 12.92 ± 2.73 MPa. Groups 1 and 2 presented significantly higher values than groups 3 and 4. It was concluded that conventional etching with 37% phosphoric acid yielded significantly higher bond strength values compared to thermal etching with the Er:YAG laser. The Nd:YAG laser did not significantly influence the bond strength.

Avaliação in vitro da resistência de união de dois sistemas adesivos dentinários à dentina bovina antes e após a termociclagem: teste de cisalhamento e análise estereomicroscópia

Pós-graduação em Odontologia Restauradora - ICT

Pré tratamento dentinário influência do condicionamento ácido, irradiação laser e hipermineralização na resistência ao cisalhamento de sistema adesivo multi uso

The disadvantages generated by the acid etching of the dentin, such as an increase in its permeability, in the surface moisture and in the potential to denature the external dentinal collagen, the formation of a fragility zone and the citotoxicity of the adhesive monomers; which are all aggravated by the depth of the dentin, have stimulated new and different treatment philosophies of the dentin. The purpose of the present study, therefore, was to investigate the effects of three dentin treatments: laser irradiation, acid etching and hypermineralization, in the shear bond strength of the SMP Plus bonding system. Sixty bovine incisors were extracted and randomly selected immediatly alter the animal's death. They were kept frozen (-18°C) for no longer than 14 days. After buccal dentinal surface had been exposed, X-Rays were taken to control the dentin thickness. The specimens were separated into two groups: (1) Control, kept in distilled water at 4ºC; (2) Mineralized, kept in hypermineralized solution at 4°C for 14 days. Each group was divided into three sub-groups according to the type of dentin treatment used: group F - followed the manufacturer instructions (acid-etching + primer + bond), group AL (acid-etching + primer + bond + laser) and group LA (laser + (laser + acid-etching + primer + bond). A composite resin standard cylinder (Z100-3M) was bond to the dentinal surface and the shear bond strength performed on a Universal lnstron machine 4301, with 500 Kg load and at 0,5mm/min. speed. The analysis of variance (ANOVA) determined that the treatments influenced the shear bond strength values (p<0,05) with the following average shearing load at failure: AL (9,96 MPa), F (7,28MPa) e LA (4,87 MPa). The interaction between the two factors analyzed Group (control and mineralized) and treatment (F, AL, LA) also influenced the shear bond strength (p<0,05). The highest values were obtained...