Platform switching on wide-diameter external hex implants a finite element analysis

Objectives: The objective of this work was to use finite element analysis to compare the effect of forces coming to bear on abutments 4.1 or 5.0 mm in diameter connected to a 5.0 mm implant (i.e. with or without platform swit - ching). Study design: A 3D CAD model of a 5 x 11.5 mm external hex implant was developed, complete with a connection screw and either of two abutments, one 4.1 and the other 5 mm in diameter, to assess the influence of two loading conditions, i.e. 200 N loaded either axially or off center on the top of the abutment. Results and conclusions: In the symmetrically loaded models, greater stresses were transmitted to the bone in the area below the neck of the implant in the case of the wider-diameter abutment. When the narrower abutment was considered, the stress lines remained confined to the metal and were transferred to the bone in a more distal position. When the stresses in the bone where compared under non-symmetrical loading of the larger- and smaller-diameter abutments, the stresses reached lower values in the latter case. These findings indicate that platform switching (i.e. coupling a 4.1 mm abutment with a 5 mm implant) achieves a better, more even distribution of the peri-implant stresses deriving from simulated occlusal loads on the bone margins

Biopolymers for Hard and Soft Engineered Tissues: Application in Odontoiatric and Plastic Surgery Field

The goal of modern dentistry and plastic surgery is to restore the patient to normal function, health and aesthetics, regardless of the disease or injury to the stomatognathic and cutaneous system respectively. In recent years tissue engineering and regenerative medicine have yielded many novel tissue replacements and implementation strategies. Scientific advances in biomaterials, stem cell isolation, growth and differentiation factors and biomimetic environments have created unique opportunities to fabricate tissues in the laboratory. Repairing of bone and skin is likely to become of clinical interest when three dimensional tissue reconstructive procedures and the appropriate supporting biomimetic materials are correctly assembled. In the present review, we provide an overview of the most promising biopolymers that may find clinical application in dento-maxillo-facial and plastic surgery