Optimizing the fitting-surface preparation of zirconia restorations for bonding to dentin.

OBJECTIVES: The aim of this study was to identify the relative strengths and weaknesses of different interfaces within the multilayer structure of a zirconia crown restoration when applying different surface pretreatments. These include the influence on shear strengths of different air abrasion protocols, glaze-on techniques, zirconia primers and self-adhesive cements for either the complex structure: zirconia / self adhesive resin composite cement (RCC) / bovine dentin substrate (part 1) or the RCC / zirconia substrate (part 2). METHODS: In Part 1, zirconia discs, pretreated by either glaze-on techniques or air abrasion using Rocatec™ Soft, were bonded to bovine dentin substrates with different self-adhesive RCCs. In Part 2, steel-cylinders were bonded to zirconia cuboid substrates, pretreated by either different protocols for air-abrasion or a glaze-on-technique, with different self-adhesive RCCs. Shear bond strengths (SBS) were measured for all interfacial combinations. RESULTS: In part 1, application of air abrasion using Rocatec™ Soft significantly increased the SBS of zirconia to dentin compared to control specimens without pretreatment, while glaze-on techniques did not increase the SBS. Pretreatment of zirconia surfaces with two primers (either Clearfil Ceramic Primer, or Monobond S) showed significantly higher SBS than the controls. Cementations with RelyX Unicem 2 Automix showed significantly higher SBS than with MaxCem Elite. In Part 2, all air abrasion protocols increased the SBS, but there was no significant difference between these protocols. Again the glaze-on technique did not increase SBS. A significant difference between the two RCCs was again observed. When zirconia substrates were air abraded, regardless of which protocol was applied, the highest SBS were obtained by Calibra with P&B active followed by Panavia with or without Clearfil Ceramic Primer Plus. Calibra applied without P&B active exhibited the lowest SBS. SIGNIFICANCE: Pretreatment of zirconia substrates using air abrasion and/or ceramic primers increased the SBS of the zirconia cement interface. For all tested glaze-on treatments, in our experimental setting no effect was observed.

Anatomy of the deep venous system in vein of Galen malformation and its changes after endovascular treatment depicted by magnetic resonance venography.

BACKGROUND AND PURPOSE: It is classically thought that the internal cerebral veins (ICV) do not communicate with the venous pouch of vein of Galen malformations (VGM). We report on the anatomy of the deep venous system in VGM with special emphasis on the drainage of the ICV and possible changes after endovascular treatment. MATERIALS AND METHODS: We retrospectively analyzed DSA and 2D time-of-flight MR venograms of 55 children with VGM. We evaluated all pre- and post-operative images for the presence of the ICVs and determined their route of venous drainage. RESULTS: Of 55 children, pre-operative 2D MRV detected the ICVs in 19 cases (35%) compared with one case (2%) for pre-embolization DSA (2%) (P<0.0001). Of the cases in which the ICVs were seen preoperatively, in 15 cases (78.9%) the ICV drained directly into the VGM while in the other four cases, the ICV used alternative venous drainage routes. On post-operative MRV, the ICVs were seen in 17 cases (31%) on MRV and 10 cases (18.2%) on DSA with drainage into an adult-like vein of Galen in 13 cases (76%), respectively (P=0.08). In four cases normal ICV drainage into the vein of Galen was seen even when the venous sac was closed. In two cases there was a change in ICV drainage from the vein of Galen to the lateral mesencephalic vein. CONCLUSION: The communication of the ICV with the VGM is a common phenomenon. Different changes of venous drainage routes do occur after treatment and are best seen on MRV.