Statement Of Problem: Various computer-aided design and computer-aided manufacturing (CAD/CAM) materials are available to fabricate complete crowns. The type of material may have an effect on the longevity of these restorations.
Purpose: To evaluate the fatigue resistance, load-to-failure, failure mode, and antagonistic wear of complete molar computer-aided design and computer-aided manufacturing (CAD/CAM) crowns made of resin nanoceramic (RNC), feldspathic glass ceramic (FEL), or lithium disilicate (LD) placed with a simplified cementation process.
Material And Methods: Forty-five molars received a standardized complete crown preparation and were restored with CAD/CAM crowns (1.5-mm thickness, n=15) made of RNC, FEL, and LD. After cementation, the restorations were submitted to cyclic isometric loading: 200 (×5000), 400, 600, 800, 1000, 1200, and 1400 N at a maximum of 30 000 cycles each. Surviving specimens were axially loaded until failure or to a maximum load of 4500 N. The specimens were analyzed as to failure mode: catastrophic, possibly repairable, and repairable. The groups were compared by using the life table survival analysis and the t test (α=.05).
Results: All the specimens survived the fatigue process until the 800-N step. The survival rate of RNC was 80%, LD 93.3%, and FEL 6.6%. The survival of RNC and LD crowns did not differ from each other but exceeded that of FEL. Postfatigue load-to-failure test was 2500 N (FEL), 3122 N (RNC), and 3237 N (LD). No catastrophic failure occurred in the fatigue test, whereas all of the specimens in the load-to-failure test exhibited catastrophic fractures. Crowns made of RNC seemed to generate the least amount of antagonistic wear.
Conclusions: Posterior crowns made of RNC and LD were not statistically different, and both had significantly higher fatigue resistance than FEL. All materials survived beyond the normal range of masticatory forces, and all failures were possibly re-restorable except those in the load-to-failure test. RNC crowns seemed to cause less wear of the antagonist.
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http://dx.doi.org/10.1016/j.prosdent.2013.09.020 | DOI Listing |
Am J Sports Med
January 2025
Mayo Clinic Arizona Department of Orthopedic Surgery, Phoenix, Arizona, USA.
Background: The Latarjet and other bony augmentation procedures are commonly used to treat anterior shoulder instability in the setting of significant glenoid bone loss. Although several fixation strategies have been reported, the biomechanical strength of these techniques remains poorly understood.
Purpose: To perform a systematic review of the biomechanical strength of glenoid bony augmentation procedures for anterior shoulder instability.
Am J Sports Med
January 2025
Department of Orthopedics and Rehabilitation, University of Vermont, Burlington, Vermont, USA.
Background: A lateral extra-articular tenodesis (LET) is increasingly being utilized to augment an anterior cruciate ligament reconstruction because it has been shown to reduce the risk of postreconstruction graft failure or recurrent rotatory instability. Various femoral fixation techniques are available, including the use of an interference screw, staple, or suture anchor.
Purpose: To determine and compare the biomechanical properties of an LET graft when using an interference screw, staple, or suture anchor for the femoral fixation for a modified Lemaire LET.
Sci Rep
December 2024
Department of Orthopedic Surgery, Yonsei University College of Medicine, Seoul, South Korea.
The unique saddle articulation of the trapeziometacarpal joint allows for a wide range of motion necessary for routine function of the thumb. Inherently unstable characteristics of the joint can lead painful instability. In this study, we modified a surgical dorsal ligament reconstruction technique for restoring trapeziometacarpal joint stability.
View Article and Find Full Text PDFJ Hand Surg Glob Online
November 2024
Florida Orthopaedic Institute, Tampa, FL.
Purpose: The purpose of this study was to evaluate the biomechanical properties of SutureTape as an alternative technique for arthrodesis of the metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joint arthrodesis when compared with surgical steel wire.
Methods: A total of 32 fingers (index, long, ring, and small) from two matched pair cadaveric hands were used. K-wire and surgical steel wire were used for MCP and PIP joint arthrodesis of the control group (group I), whereas K-wire and SutureTape were used for the experimental group (group II).
J Prosthodont
December 2024
Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Bern, Switzerland.
Purpose: To evaluate the effect of material type on dimensional stability, occlusal surface wear, fracture resistance, and failure behavior of resin-based onlay restorations.
Material And Methods: A mandibular right first molar typodont was prepared and digitized using an intraoral scanner to virtually design an onlay restoration with the minimum occlusal thickness of 1.5 mm.
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