CAD/CAM Preparation Design Effects on Endodontically Treated Molars
Abstract
To evaluate the static load fracture resistance of endodontically treated molars restored with lithium dislicate full coverage restorations using either the Endocrown technique or crowns based on preparations comprised of composite cores with various dentin axial wall heights. Materials and Methods: 48 recently extracted human molars were endodontically accessed, pulp chamber debrided and canals instrumented by a board-certified endodontist. Teeth were randomly assigned in four groups and embedded in acrylic. Groups were then randomly placed into four restoration schemes: Endocrown; and three composite core restored preparation designs consisting of two millimeters dentin axial wall height (AWH), one millimeter AWH, and a group containing minimal AWH. Resin composite cores restorations were placed according to assigned group with all manufacturer instructions followed. After 24 hours storage, specimens were prepared according to planned dentin AWH scheme. Endocrown preparation designs, consisted of a 2mm deep chamber retention. Preparation heights and surface area was measured using a digital microscope (Hirox).To simulate clinical conditions, an acrylic scanning jig was fabricated with an opening in the first molar position. Each specimen was inserted into the scanning jig and digitally captured with using a CAD/CAM device. Designed lithium disilicate crowns were milled, crystallized, intaglio surfaces prepared according to manufacturer instructions and cemented with a self-adhesive resin luting agent after preparations were cleansed with a pumice/water slurry and were stored in distilled water under dark conditions. After 24 hours, specimens were placed onto a universal testing machine at a 45-degree angle to the long axis and loaded to failure at a rate of 0.5 mm/min. Peak Force (Newtons) recorded with mean data analyzed with Kruskal-Wallis/Dunns post hoc at a 95 percent level of confidence (a=0.05) Results: The composite core group with a preparation at two
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 21, 2018
- Accession Number
- AD1128466
Entities
People
- Elizabeth M. Litman
Organizations
- Uniformed Services University of the Health Sciences