Concepts for Designing and Fabricating Metal Implant Frameworks for Hybrid Implant Prostheses

Abstract

Edentulous patients have reported difficulties in managing complete dentures; they have also reported functional concerns and higher expectations regarding complete dentures than the dentists who have treated them. Some of the objectives of definitive fixed implant prosthodontic care include predictable, long-term prostheses, improved function, and maintenance of alveolar bone. One of the keys to long-term clinical success is the design and fabrication of metal frameworks that support implant prostheses. Multiple, diverse methods have been reported regarding framework design in implant prosthodontics. Original designs were developed empirically, without the benefit of laboratory testing. Prosthetic complications reported after occlusal loading included screw loosening, screw fracture, prosthesis fracture, crestal bone loss around implants, and implant loss. Numerous authors promoted accurately fitting frameworks; however, it has been noted that metal frameworks do not fit accurately. Passively fitting metal implant frameworks and implants have not been realized. Biologic consequences of ill-fitting frameworks were not well understood. Basic engineering principles were then incorporated into implant framework designs; however, laboratory testing was lacking. It has been reported that I- and L-beam designs were the best clinical option. With the advent of CAD/CAM protocols, milled titanium frameworks became quite popular in implant prosthodontics. The purpose of this article is to discuss current and past literature regarding implant-retained frameworks for full-arch, hybrid restorations. Benefits, limitations, and complications associated with this type of prosthesis will be reviewed. This discussion will include the relative inaccuracy of casting/implant fit and improved accuracy noted with CAD/CAM framework/implant fit; cantilever extensions relative to the A/P implant spread; and mechanical properties associated with implant frameworks including I- and L-beam designs. Guidelines will be proposed for use by clinicians and laboratory technicians in designing implant-retained frameworks.

Novel Bio-functional Magnesium Coating on Porous Ti6Al4V Orthopaedic Implants: In vitro and In vivo Study

“…Bone healing and growing into titanium implant is recognized to follow a sequential and overlapping series of events including osteoblastic lineage attachment and cell proliferation, differentiation which eventually lead to bone tissue regeneration47. Nevertheless, how to improve the osteointegration and osteogenesis properties of these porous titanium and its alloy is still a major concern for their clinical applications891011. Magnesium and its alloys have been considered as a revolutionary biodegradable implant material and are widely studied recently as a new type of biomedical materials due to the prominent advantages in mechanical property, biodegradability and biocompatibility484950.…”

“…Although titanium based medical devices have been used clinically for more than 30 years, there are still weaknesses for the implants that need to be resolved. The lack of osteo-conduction and integration into the bone for long-term survival often occur and lead to implant failure891011. Therefore the challenges for Ti-based implants are incorporating with osteo-integration, and also enhanced bioactivity with bone healing and regeneration, thus improving implant-host interactions so as to reduce biological related implant failure.…”

Use of intraoral digital scanning for a CAD/CAM-fabricated milled bar and superstructure framework for an implant-supported, removable complete dental prosthesis

“…The CAD/ CAM approach provided an accurate, cost-effective pathway for fabricating the definitive prostheses. 8,9 In this clinical report, a subtractive manufacturing process was used to fabricate the milled bar, and an additive manufacturing process with selective laser melting was used to fabricate the superstructure framework. This process may provide a more time-and cost-effective approach than conventional casting techniques.…”

The Evolution of Dental Materials for Hybrid Prosthesis

“…Frameworks were fabricated according to the following criteria: bulk for strength, adequate access for oral hygiene procedures, minimal display of metal on the facial and occlusal surfaces, and strategic thinning of implant frameworks to allow for retention of acrylic resin denture teeth and denture basses [28]. …”