Objective: This clinical study was conducted to assess the marginal bone level around two different types of implant abutment junctions which are the platform-switched connection and non-platform- switched connection used in cases of implants supporting mandibular overdentures following the immediate loading protocol. Materials and Methods: Twelve completely edentulous male patients were randomly divided into two equal groups: Group I: Each patient received two Legacy I Implants designed with internal bevel having 3.5mm implant platform diameter to which 3.5mm neck diameter healing collars were threaded creating a matching or non-platform switching mechanism at the implant abutment junction. Group II: Each patient received two Screw Plant Implants designed with external bevel having 3.7mm implant platform diameter to which 3.5mm neck diameter healing collars were threaded creating platform switching mechanism at the implant abutment junction. All implants were inserted bilaterally in the mandibular canine region following one stage surgical protocol. Ten days following the surgery all patients received mandibular overdentures and once patients were comfortable to the prosthesis, they were placed on a zero, six, and twelve months follow-up periods. Radiographic evaluation of peri-implant crestal bone height changes was taken using cone Beam Computed Tomography (CBCT). Results: Both groups showed reduction in the crestal bone height however, Group II with platform- switched implant abutment junction showed less crestal bone resorption than Group I with non-platform-switched implant abutment junction. Conclusion: Within the limitations of this study it could be concluded that the platform switching mechanism at the implant abutment junction preserves the crestal bone surrounding the implants that support mandibular overdentures.
Rizk, Fardos N. and Elrekaby, Eatmad, "Radiographic Evaluation of Marginal Bone Levels Around Platform-Switched Implants and Non-Platform-Switched Implants Immediately Loaded to Support Mandibular Overdenture" (2013). Dentistry. 90.