Platform switching is one of them.

Abstract
Crestal bone loss has been documented as one of the important factors that affect the long term prognosis of a dental implant. Various factors responsible for crestal bone loss have been reviewed. The concept of platform switching has been described on a histological basis. Its clinical benefits are discussed. A finite element analysis was performed to assess the mechanical behaviour of platform switched implants, which shows reduced crestal stress values under occlusal loads.

Introduction
The success of dental implants is highly dependent upon the integration between the implant and the intraoral hard/soft tissue.The initial breakdown of the implant-tissue interface generally begins at the crestal region in successfully osseointegrated endosteal implants regardless of surgical approaches, with the potential to cause implant failure.
The first report quantifying early crestal bone loss was a 15 year retrospective study by Adell et al. He reported 1.2 mm marginal bone loss from the first thread during healing and in the first year after loading with average 0.1 mm bone loss annually thereafter.
The criteria for implant success as given by Smith and Zarb who stated that vertical bone loss (< 0.2 mm) annually following first year of implant function. A post-restorative remodeled crestal bone generally coincides with the level of the first thread on most standard diameter implants. The first thread changes the shear force of the crest module to a component of compressive force to which the bone is most resistant. FACTORS AFFECTING CRESTAL BONE LOSS 1. Surgical Trauma Surgical Trauma due to heat generated during drilling elevation of the periosteal flap and excessive pressure at the crestal region during implant placement may contribute to implant bone loss during the healing period. Wildermann et al reported that bone loss due to periosteal elevation was restricted to the area just adjacent to the implant, even though a larger surface area of the bone was exposed during surgery. Early implant bone loss is in the form of horizontal saucerization. However, bone loss after osseous surgery in natural teeth is more vertical. Signs of bone loss from surgical trauma and periosteal reflection are not commonly observed at the implant stage II surgery in successfully osseointegrated implants. Thus, surgical trauma is unlikely to cause early crestal bone loss. 2. Biological Width / Seal Biological width forms within the first six weeks after the implant/abutment junction has been exposed to the oral cavity. It is a barrier against bacterial invasion and food ingress implant-tissue interface. The ultimate location of epithelial attachment following phase 2 surgery in part, determines early post-surgical bone loss. Thus, implant bone loss is in part, a process of establishing the biological seal. 3. Microgap In most of the 2 stage implant systems, after abutment is connected, a microgap exists between the implant and the abutment at or below the alveolar crest. For all 2 stage implants, the crestal bone levels are dependent upon the location of the microgap ~ 2mm below it. The countersinking below the crest is done to minimize the risk of implant interface movement during bone remodeling, to prevent implant exposure during healing and also to enhance the emergence profile. Countersinking places the implant micro gap below the crestal bone. The microgap-crestal bone level relationship was studied radiographically by Hermann et al, who for the first time, demonstrated that the microgap between the implant/abutment has a direct effect on crestal bone loss, independent of surgical approaches. Epithelial proliferation to establish biological width could be responsible for crestal bone loss found about 2mm below the microgap. 4. Occlusal Overload Excessive stress on the immature implant bone interface in the early stage of prosthesis in function is likely to cause crestal bone loss. Cortical bone is least resistant to shear force, which is significantly increased in bending overload. However, bone loss from occlusal overload is considered to be progressive rather than limited to the first year of loading. 5. Crest Module The transosteal region of the implant receives crestal stresses after loading. The crest module design can transmit different types of forces onto the bone, which depends upon its surface texture and shape. A polished collar and a straight crest module design transmit shear force, whereas a rough surface with an angled collar transmits beneficial compressive force to the bone. Research on crestal bone loss around dental implants has largely focused on implant systems with matching diameter implant seating surfaces and restorative components. In 1991, the 3i wide diameter 5.0 and 6.0 mm implants were designed with a matching diameter seating surface to be used mainly for poor quality bones to achieve improved stability. However, when introduced, there were no matching diameter prosthetic components available, and as a result, most of the initially placed implants were restored with standard 4.1 mm diameter components, which created a 0.45mm or 0.95 mm circumferential horizontal difference in dimension. Radiographical reviews after the initial 5 year period revealed that when matching diameter implants and restorative components are used, the crestal bone contacting the implant normally remodelled to ~ 1.5-2 mm apically ~ to the first thread. In contrast, when smaller diameter components were placed on wider diameter platforms, the amount of crestal remodelling was reduced. Many platform switched restored implants exhibited no vertical loss in crestal bone height. Thus, the discovery of the concept was a serendipity!