Today more and more dentists are choosing implant therapy over conventional method of tooth replacement, correspondingly a rise in the number of complications related to biology, technical and aesthetic have been reported. Methods of diagnosis, etiology and risk factors have been identified in a number of experimental and clinical studies done recently by many workers. In addition, a number of non-surgical, surgical, and regenerative therapies have been suggested in the management of peri-implantitis. The three clinical cases, presented in this chapter, cover the range of problems and complications that can occur. The first case is a case of peri-implantitis and tissue destruction after immediate implantation due to elastomeric impression material inadvertently left behind. The second case is due to overheating of bone due to placement of implant at high speed. The third case is related to an aesthetic problem due to labial placement of an implant in the anterior maxilla.