In vitro lifetime of zirconium dioxide‐based crowns veneered using Rapid Layer Technology

Abstract

Rapid Layer Technology (RLT) uses computer‐aided design/computer‐aided manufacturing (CAD/CAM) to manufacture a veneer layer that is adhesively bonded to the zirconia framework, avoiding firing steps during the fabrication process and thus preventing build‐up of residual stresses. This work studied, using sliding contact fatigue, the in vitro lifetime of restorations produced using RLT compared with restorations produced using conventional veneering techniques. Zirconia copings were veneered with a conventional hand‐layering method (VM9) using a fast (n = 16) or a slow (n = 16) cooling protocol, or with RLT. For the latter, the veneers were CAD/CAM fabricated using a feldspathic reinforced‐glass (Vitablocs Mark II; n = 16) or a polymer‐infiltrated reinforced‐glass network (Enamic; n = 16) and adhesively bonded to the zirconia frameworks. Crowns thus obtained were submitted to sliding contact fatigue against a steatite indenter in a chewing simulator until failure. A Kaplan–Meier survival analysis was conducted. None of the hand‐layered restorations survived after a 2 × 106‐cycle interval, whereas no fractures in the RLT groups were observed. Vitablocs Mark II veneers survived for a longer testing period (3.5 × 106 cycles) than their Enamic counterparts (2.5 × 106 cycles) owing to their superior wear behavior. The RLT represents an efficient method to veneer zirconia frameworks by reducing processing steps and, more importantly, increasing the lifetime of the restorations.

Aging and Fracture Resistance of Implant-Supported Molar Crowns with a CAD/CAM Resin Composite Veneer Structure

“…The Rapid Layer Technology (RLT) implies the CAD/CAM fabrication of a milled veneer structure that is adhesively bonded to a framework. Some in-vitro studies have already investigated the aging and/or fracture behavior of veneer structures from silica-based materials [ 9 , 10 , 11 , 12 ]; however, information on other esthetical tooth-colored materials for veneer structures in an RLT approach is scarce [ 8 , 13 ].…”

Effect of three different veneering techniques on the stress distribution and in vitro fatigue behavior of core-veneer all-ceramic fixed partial dentures

“…As an alternative, computer-aided design/computer-aided manufacture (CAD/CAM) workflow has been developed to fabricate both the veneer and framework structures from homogenous ceramic blocks that have been manufactured in optimized conditions. 17 The two CAD/CAM parts are subsequently joined using a composite resin layer (Rapid Layer Technique, VITA Zahnfabrik, VITA Zahnfabrik, Bad Säckingen, Germany) 18 or with a low fusing temperature glass-ceramic (IPS e.max CAD Veneering Solutions, CAD-on technique, Ivoclar Vivadent, Schaan, Liechtenstein). 19 The fracture resistance of the resulting ceramic bilayer will depend on many geometric, material, and processing variables, 18 , 19 and the interface between the two layers for core-veneer all-ceramic restorations has been identified to be important in determining the fracture behavior.…”

“… 17 The two CAD/CAM parts are subsequently joined using a composite resin layer (Rapid Layer Technique, VITA Zahnfabrik, VITA Zahnfabrik, Bad Säckingen, Germany) 18 or with a low fusing temperature glass-ceramic (IPS e.max CAD Veneering Solutions, CAD-on technique, Ivoclar Vivadent, Schaan, Liechtenstein). 19 The fracture resistance of the resulting ceramic bilayer will depend on many geometric, material, and processing variables, 18 , 19 and the interface between the two layers for core-veneer all-ceramic restorations has been identified to be important in determining the fracture behavior. 18 , 20 It is proposed that effective stress transfer mediated by a stable joint between layers promotes greater fracture resistance under masticatory forces.…”

“…19 The fracture resistance of the resulting ceramic bilayer will depend on many geometric, material, and processing variables, 18 , 19 and the interface between the two layers for core-veneer all-ceramic restorations has been identified to be important in determining the fracture behavior. 18 , 20 It is proposed that effective stress transfer mediated by a stable joint between layers promotes greater fracture resistance under masticatory forces. 21 - 28 However, these techniques have not been compared before regarding stress distribution and fatigue survival.…”