Book excerpt: The goal of modern dentistry is to restore the patient function, comfort, esthetics speech & health, which can be done by removing caries from a tooth and restoring it, or by replacing missing teeth. What makes implant dentistry unique is the ability to achieve this goal, regardless of atrophy, disease, or any injury of the stomatognathic system. As a result of latest researches, diagnostic tools, treatment planning, implant designs, materials and techniques, predictable success is now a reality for the rehabilitation of many challenging clinical situations. Dental implants are the treatment of choice for the replacement of missing teeth nowadays. However, placement of the implant in alveolar bone remains a challenge for most of the clinicians due to the resorption of the residual alveolar ridge, resulting in insufficient bone volume in one or more dimensions. The purpose of this book is to discuss and elaborate the review various complications and failures in implantology before and after the placement of a dental implant.