The purpose of this study was to compare the flexure strength of zirconium dioxide materials designed for different sintering techniques before and after surface exposure to an acidic solution and to correlate the dissolution of the materials with strength data.

Determination of fracture strength of different all-ceramic dental crown systems is not straight forward. Most in vitrotest methods induce contact damage at the loading point (crunch the crown-tests). Clinical failures, on the other hand, usually originate from cracks in the cervical margins. The aim of this study was to compare three all-ceramic systems using a test method that mimic clinical failure modes.

Fracture strength measured in vitro indicates that most all-ceramic crowns should be able to withstand mastication forces. Nevertheless, fractures are one of the major clinical problems with all-ceramic restorations. Furthermore, the fracture mode of all-ceramic crowns observed in clinical use differs from that found in conventional fracture strength tests. The aim of the present study was to develop and investigate a method that simulates clinical fracture behavior in vitro

Svært mye har skjedd innen materialvalg for dentale kroner og broer de siste to tiår. Keramer har overtatt mye av metallenes plass. Fra de første aluminiumsoksidforsterkede porselener og det pene, men altfor skjøre glasskeramet Dicor (1), har det på kort tid blitt utviklet materialer og teknologi som har skjøvet tradisjonell tannteknikk til side. Faget har fått et helt nytt område å forholde seg til, nemlig avansert datateknologi med digitale, optiske 3D-skannere og numerisk styrte roboter for produksjon av individuelt tilpassede produkter (2).

Toxic elements may be released by corrosion of orthodontic appliances, contribute to adverse patient reactions. Previous studies have shown that the composition of orthodontic attachments is complex in that several different alloys are used in the same attachment. The close contact of alloys with different composition enhances the galvanic corrosion of the attachment in the oral cavity where saliva acts as an electrolyte.