Considering the known importance of other restrictions, e g alum

Considering the known importance of other restrictions, e.g. aluminium toxicity or iron nutrition, it is likely that these factors, together with N form preference, act

in concert. Our finding that species interaction impacts on such interrelations in an unexpected manner poses a future challenge to devise multi-factorial experiments on species occurrence along soil reaction gradients.”
“Statement of problem. Debonding is a common cause of failure encountered with fiber-reinforced composite (FRC) posts, and usually occurs along the post space-dentin adhesive interface. Surface conditioning of posts is expected to increase the chemical and mechanical bond between the luting composite resin and the post, but the best method has not been definitively determined.\n\nPurpose. The purpose of this in vitro study was to compare the effects of 3 surface-conditioning methods on the retentive bond strengths of FRC posts using 5 composite resin materials, and compare results to those of unconditioned FRC posts as well.\n\nMaterial and methods. Post space preparations (DentinPost ER root post system, length of 12 mm) were performed BAY 73-4506 purchase on 200 human anterior teeth. Groups of 50 FRC posts (ISO size 90) each were treated using I of the following conditioning methods: silanization, etching with 5% hydrofluoric

acid, tribochemical coating (CoJet system), or were left untreated (control group). FRC posts (n=10) in each group were placed using 1 of 5 composite resin materials (Calibra or RelyX Unicem resin cements or Build-It, MultiCore Flow, or Rebilda DC foundation composite resins). Following water storage (37 degrees C, 24 hours) and thermal cycling (5000 cycles, 5 degrees-55 degrees C, 30-second dwell time), tensile strength testing was performed. Fracture modes were assessed using a light microscope. Data were analyzed statistically (1-way and 2-way ANOVA, Bonferroni-Dunn correction, alpha=.05).\n\nResults. Retentive bond strengths

of FRC posts luted with MultiCore Flow in combination BKM120 chemical structure with the CoJet system, and of posts inserted with Rebilda DC in combination with hydrofluoric acid (HF) etching as well as with the CoJet system, were significantly higher than those of the corresponding unconditioned FRC posts (P<.001). No significant differences were noted between the bond strength values of RelyX Unicem with CoJet, MultiCore Flow with CoJet, and Rebilda DC with either CoJet or HF etching (P>.05). Retentive bond strengths were significantly lower for HF etching (Calibra, RelyX Unicem, Build-It), and for the treatment with the CoJet system in combination with Build-It compared to the corresponding control groups (P<.001). Fracture modes were primarily adhesive at the post surface or cohesive within the composite resin layer or within the FRC post.\n\nConclusions.

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