Increasingly, modern periodontology and implantology face mistreatments, complications, failures, and even iatrogenic damages. It is therefore deemed valuable for colleagues and patients to share protocols, techniques, instruments, materials, and innovations developed to retreat these clinical cases with no room for error. All clinical cases described have only one parameter in common: a medical mistake. Retreating these "special patients" requires passion, ethics, and the willpower to help patients who present with very high expectations and an exacting psychological makeup. Variables such as periodontal biotype, biologic and anatomic potential for tissue regeneration, and the nature of the underlying osseous architecture surrounding the ailing teeth or endosseous implants will influence the clinical decision making toward achieving optimal "biomimetic" results. The decision to perform implant treatment is ideally driven by the latest evidence-based information, in addition to the educational background, clinical experience, and access to technology of the periodontist; patient and site risk assessment; predictors of disease; economic aspects; probabilities and uncertainties of treatment outcome; and long-term stability of the results.
