Title: 1301 - Fatigue Resistance of 1mm Thickness CAD/CAM Crowns
Anthony Randi, columbia universtiy
mohammad abumelha (Presenter)
Objectives: To investigate the fatigue resistance of CAD/CAM lithium disilicate , monolithic Leucite-based glass-ceramics and zirconia reinforced lithium silicate of 1 mm full contour crowns adhesively luted to composite resin abutments.
Methods: Eighty standardized maxillary molar crowns were CAD/CAM milled using three different materials; monolithic lithium disilicate [IPS e.max®CAD], monolithic Leucite-based glass-ceramics [IPS Empress®CAD] and zirconia reinforced lithium silicate [CELTRA® DUO (ZLS) Polished and Crystallized]. Crowns were adhesively luted on CAD/CAM milled [Lava™ Ultimate] abutments using dual cure cement . All specimens were stored at 37oC for 24h. Crowns were loaded applying an eccentric force in a Willytec chewing simulator (steel stylus, cusp to fossa movment) with stepwise decrease of the load (21.3 , 19.3 , 17.3 , 15.3, 13.3 and 11.3 kg, 200,000 cycles each, 0.8 Hz). A two-way ANOVA and Tukey’s post hoc test will be used, at the level of 0.05 significance to test the fatigue resistance of the materials.
Results: The fatigue resistance measurements revealed that the monolithic lithium disilicate was superior to zirconia reinforced lithium silicate (fired). Lithium silicate unfired-polished revealed fatigue resistance similar to Leucite-based glass-ceramics respectively.
Conclusions: Monolithic CAD/CAM lithium disilicate demonstrate improved fracture fatigue compared to ZrLiSi (fired and polished) and leucite reinforced ceramics.
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: NONE