Abstract
Objectives: This study compared the influence of occlusal anatomy on acrylic CAD/CAM crowns fracture load and stress distribution. The null hypothesis was that there would be no difference between the provisional crowns fracture load and stress according to different occlusal anatomy.Methods: A full-crown preparation was simulated using dentin analogue (G10, Protec, São Paulo, Brazil) totaling 20 identical preparations. Next, twenty acrylic crowns were milled using different occlusal design parameter (Young or Adult) available in the software database. The crowns were cemented (Temp-bond, NE Kerr Dental, Brea, CA, USA) and fractured using a compressive load (0.5 mm/min of cross-head speed). Data were analyzed by using one-way ANOVA and Tukey tests (p< 0.05). A similar geometry was modeled and exported to the analysis software to perform a static structural analysis. The maximum principal stress was calculated using the finite element method with 300 N chewing load simulation.Results: The occlusal anatomy significantly influenced the load-to-fracture (p<0.05). Young design showed lower fracture load (1139±132 N) than Adult design (2007±345 N). The tensile stress distribution showed a similar pattern for both groups however the highest stress peak was calculated for Young design (76 MPa) in the occlusal surface.Conclusion: The anatomy design with higher cusp angulation and occlusal sulcus more evident can increase the stress concentration and reduce the fracture load for acrylic resin CAD/CAM crowns.
Highlights
Temporary crowns are indicated to be used as an intermediate restoration between the time of tooth preparation and the final indirect restoration procedure [1,2]
Computer-aided design and computer-aided manufacturing (CAD-CAM) method allow the manufacture of acrylic crowns in pre-polymerized conditions, which improves mechanical properties, reduces discoloration, and increases the anatomy precision and reduces the marginal gap [3]
The null hypothesis was that there would be no difference between the provisional crowns fracture load and stress according to different occlusal anatomy
Summary
Temporary crowns are indicated to be used as an intermediate restoration between the time of tooth preparation and the final indirect restoration procedure [1,2]. Computer-aided design and computer-aided manufacturing (CAD-CAM) method allow the manufacture of acrylic crowns in pre-polymerized conditions, which improves mechanical properties, reduces discoloration, and increases the anatomy precision and reduces the marginal gap [3]. Another advantage of polymerbased CAD/CAM materials is their good machinability [4]. Crowns with thicker margins, smaller convergence angle and fully bonded are recommended for increasing fracture resistance final restorations [8] This can be justified because a greater crown thickness and cusp angle resulted in a higher crack initiation load [9]. The null hypothesis was that there would be no difference between the provisional crowns fracture load and stress according to different occlusal anatomy
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
