In clinical practice, dentists are faced with the dilemma of whether to treat, maintain, or extract a tooth. Of primary importance are the patient's desires and the restorability and periodontal condition of the tooth/teeth in question. Too often, clinicians extract teeth when endodontic therapy, crown-lengthening surgery, forced orthodontic eruption, or regenerative therapy can be used with predictable results. In addition, many clinicians do not consider the use of questionable teeth as provisional or transitional abutments. The aim of this article is to present a novel decision tree approach that will address the clinical deductive reasoning, based on the scientific literature and exemplified by selective case presentations, that may help clinicians make the right decision. Innovative decision tree algorithms will be proposed that consider endodontic, restorative, and periodontal assessments to improve and possibly eliminate erroneous decision making. Decision-based algorithms are dynamic and must be continually updated in accordance with new evidence-based studies. Schlagwörter: decision trees, periodontal prognosis, questionable teeth, treatment planning