Dental Tribune United Kingdom Edition

15Implant TribuneMay 23-29, 2011United Kingdom Edition O ver the last decades, osseointegrated dental implants have proven to be highly predictable and large- ly accepted as treatment modality for the rehabilitation of partially and completely edentulous jaws. Being considered the most aes- theticalandfunctionalalternativeto missing teeth, dental implants are used as prosthetic supports and ex- pectedtowithstandcomplexocclu- sal load. However, they also have to confront the effects of additional factors such as oral microflora or elevated parafunctional forces. Several factors such as im- plant design and surface, im- plant abutment interface or connection, bone architecture, prosthodontic restoration type and loading conditions may have effect on bone modelling and re- modelling around the implants. The generally accepted cri- terion for implant success is that less than 0.2mm of alveolar bone loss per year should occur after the first year in function.1 What is overlooked, however, is that the implant therapy success is deter- mined after the first year of serv- ice because most of the bone loss occurs during the first 12 months following abutment connection.2 Therefore, the 2mm loss of crestal bone over the first year might be considered a normal characteristic of a healthily func- tioning implant and this change in bone height is merely due to re- modelling in response to loading. The questions that need to be redressed are whether this small amount of bone loss exerts any clinical significance and whether it can be considered acceptable. Dental implants have two goals to fulfil: an aesthetic one and func- tional one. The loss of crestal bone and soft tissue may have important implications for aesthetic implant restorations, which are reliant on healthy and constant soft tissue dimensions over time. The aes- thetic replacement of teeth has become an important standard for implant dentistry, leading to fur- ther research regarding the factors contributing to crestal bone loss around two stage implants (Fig. 1). Bone adaptation under load- ing conditions Bone is a tissue that changes its mass and internal architecture adapting itself to the loading con- ditions. According to Wolff’s law16 , every change in the form and function of bone is followed by modifications in its internal ar- chitecture and external conforma- tion. The dimensions and orienta- tion of trabeculae are adaptable in accordance with changes in load- ing trajectorial vectors and, when equilibrium is found, trabecular patterning represents the average regime experienced by the bone.17 Mechanical stimuli affect bone response and exert influence on the replication and differentiation of mesenchymal cells toward the osteoblast lineage. 18 Frost’s theory Frost stated that bone mass chang- es when absolute peak strains in- duced inside the bone fall either below or above the physiological window estimated between 200 and 1,500 microstrains. The concept of “platform switching” in im- plant dentistry: A literature review—Part I Virgil Koszegi Stoianov, Romania reviews the latest literature page 16DTà BioHorizons comprehensive Biologic product portfolio offers a wide range of evidence-based regeneration options to ensure ideal site development. Delivering optimal aesthetics and successful implant placement is the goal of our proven hard and soft tissue products. foundation for optimal aesthetics *Histologic Evaluation of Autogenous Connective Tissue and Acellular Dermal Matrix Grafts in Humans. Cummings LC, Kaldahl WB, Allen EP. J Periodontol 2005;76(2):178-186. MinerOss manufactured by Osteotech. Mem-Lok manufactured by Collagen Matrix, Inc. AlloDerm manufactured by LifeCell. SPMP09095 REV A APR 2009 Biologic Solutions • AlloDerm® – regenerative tissue matrix for use as an effective alternative to palatal tissue for soft tissue augmentation* • MinerOss™ – blend of mineralized allograft cancellous and cortical chips that provide an osteoconductive scaffold for bone regeneration • Mem-Lok™ – resorbable collagen membrane that is cell occlusive and slowly resorbing to promote clot maintenance and bone formation Gingival recession with root surface restorations. Case courtesy of Dr. Edward P. Allen AlloDerm graft placed in pouch and sutured. Complete root coverage at one year postoperatively. For more information, contact BioHorizons Customer Care: 01344 752560 Email: infouk@biohorizons.com visit us online at www.biohorizons.com