No abstract

In this study, we evaluate the influence of post surface pre-treatments on the bond strength of four different cements to glass fiber posts. Eighty extracted human maxillary central incisors and canines were endodontically treated and standardized post spaces were prepared. Four post pre-treatments were tested: (i) no pre-treatment (NS, control), (ii) sandblasting (SA), (iii) silanization (SI) and (iv) sandblasting followed by silanization (SS). Per pre-treatment, four dual-cure resin cements were used for luting posts: DMG LUXACORE Smartmix Dual, Multilink Automix, RelyX Unicem and Panavia F2.0. All the specimens were subjected to micro push-out test. Two-way analysis of variance and Tukey post hoc tests were performed (α=0.05) to analyze the data. Bond strength was significantly affected by the type of resin cement, and bond strengths of RelyX Unicem and Panavia F2.0 to the fiber posts were significantly higher than the other cement groups. Sandblasting significantly increased the bond strength of DMG group to the fiber posts.

This study was designed to evaluate the shear bond strength of an adhesive/composite system subjected to different pretreated polyetheretherketone (PEEK) surfaces using different thermocycling conditioning methods. A total of 128 specimens were equally divided into four main groups ( n = 32/group): control (no pretreatment), air abrasion, argon plasma pretreatment, and femtosecond laser groups. The surface topographies and surface roughness were observed by atomic force microscopy after different pretreatments. The specimens were bonded with SE Bond/Clearfil AP-X™. All bonded specimens were stored in distilled water at 37°C for 24 h. Afterward, each group was divided into three subgroups ( n = 8/group) as follows: (a) stored in water for 56 h (37°C); (b) thermal aging for 5000 cycles (5°C/55°C); and (c) thermal aging for 10,000 cycles (5°C/55°C). The shear bond strengths were measured. Air abrasion, argon plasma pretreatment, and femtosecond laser significantly strengthened the bond of SE Bond/Clearfil AP-X™ to PEEK composite compared with that without additional pretreatment. In the same surface pretreatment, the shear bond strengths of specimens conditioned using water storage were higher than that using thermocycles (TCs). Additionally, the specimens with 5000 TC showed significantly higher shear bond strength than that with 10000 TC.

This paper is intended to offer a theoretical basis for clinical appliance of preheating by comparing the properties of six different resin composites at room temperature and pre-heated temperature. The experiment is divided into two groups: one at room temperature (20 , the other at preheated temperature (60 ). At room temperature, the six resin composites were exposed to a LED light for 20 seconds. While in the other group, the resins were firstly put into an incubator which is elevated to 60 , and then taken out. After 60 seconds, they were exposed to LED light for 20 seconds. In each group, the compressive strength, micro Vickers hardness and the degree of conversion of six resin composites were tested. After being filled with resin composites, the extracted teeth were dyed and sliced. The microleakage of the restoration was observed and then recorded. All the data was analyzed by statistical analyses. Preheating has no apparent effect on compressive strength, hardness and degree of conversion of Filtek TM Z350, Surefil, Solitaire2, ESTELITE , BRILLIANT New Line, but significantly improved the compressive strength and the hardness of GRADIA DIRECT. And preheating also reduces the microleakage of resins, especially for Surefil and Solitaire2. Preheating has effect on the properties of resin composites, and different resins differ in the sensitivity to preheating due to their different components and contents. In clinical, we ought to fully consider the value of preheating according to requirement in order to obtain the benefit.