Failure of dental implant due to lack of attached gingivaFailure of dental implant due to occlusal trauma (caused by poor prosthetic design)Failure of dental implant due to parafunctional habitsFailure of dental implant due to periodontal infection (peri-implantitis)Failure of dental implant due to poor oral hygieneIatrogenic post-osseointegration failure of dental implantPost-osseointegration failure of dental implant due to complications of systemic disease