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UBC Theses and Dissertations

Surface preparation effect on bonding to e.max cad : a fracture mechanics approach Zaeimdar, Faranak


Objective: To assess the effect of surface preconditioning on the short and long term interfacial fracture toughness (KIC) of IPS e.max CAD and an adhesive resin luting cement. Material and Methods: The materials selected for this study were from Ivoclar-Vivadent, Liechtenstein: e.max CAD blocks, Multilink implant, Mono Bond Plus, and IPS Ceramic Etching Gel. Eighty (4x4x4x4 mm) triangular prisms were cut from IPS e.max CAD blocks, crystallized and then randomly assigned to two different surface treatment groups: a) machined, using a 60 µm diamond bur (Henry Schein, Germany) and b) machined, as in group a followed by 20 s 5 % HF acid-etching. After surface treatment, all specimens were silane-treated for 60 s and the cement was used to bond two identical specimens of each group, following the manufacturer’s instructions. All 40 specimens were stored in water at 37 °C until testing. After 24 hours storage, 10 specimens from each group were tested to determine interfacial KIC using a universal testing machine (Instron 4311, Instron Canada, Canada); the other 10 specimens were tested after 60 days water storage. SEM fractographic analysis was performed on representative fractured KIC samples from each group to assess the type of failure, i.e. adhesive, cohesive, or mixed. To determine ARC KIC, twenty (4x4x4x8 mm) triangular prisms were prepared using a mould. Half of the specimens were tested after 24 hours storage in water at 37 °C and the other half were tested after 60 days. The KIC results were analyzed using univariate ANOVA followed, if warranted, by Scheffé multiple means comparisons. The statistical analysis was conducted at =0.05, using SPSS (SPSS for Windows, version 12.0; Chicago, IL). Results: The machined/etched group had a significantly higher interfacial KIC at 24 hours. Crack propagation occurred through the adhesive resin and the resin-ceramic interface. Conclusions: The higher KIC was achieved with HF acid etching. Storage in 37 °C water for 60 days led to a deterioration of both cement KIC and cement-mediated interfacial KIC. Clinical significance: IPS e.max CAD/CAM crowns should be etched with HF acid prior to cementation. However, the durability of the bond decreased upon ageing.

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Attribution-NoDerivs 2.5 Canada