Although there are no published randomized clinical trials which directly prove crown design is linked to peri-implantitis, it has long been established that inadequate subgingival margins of crowns change the microflora and lead to inflammation around natural teeth. It is intuitive that the same principles should apply when considering crown design on dental implants to minimize the likelihood of peri-implant disease (Figure 4A, 4B, and 4C).26,27
Cone Beam CT prior to implant placement facilitates optimal placement of the soft tissue component of the fixture, i.e., the coronal most portion of the dental implant with a 1.8 mm polished collar, so that the implant shoulder and crown margin are located close to the mucosal surface. Non-submerged implant fixtures with passive fits to the other components, should minimize irritation to adjacent soft tissue.
Residual cement associated with temporary or permanent crown placement on a dental implant may irritate the surrounding soft tissues, contribute to poor plaque control directly or by creating a rough surface, and promote bacterial plaque formation.28 Accumulation of biofilm, in turn, triggers soft tissue inflammation, which if unchecked progresses to peri-implantitis.