Introduction: Cognitive biases affect perception, memory, thinking and judgment. Mostly, they are the result of heuristics, i.e. mental shortcuts accelerating the decision-making process. In medicine, several biases can be recognized in both patients and practitioners such as choosing between treatment options and making errors in diagnostics and therapy, respectively. Methods: In order to synthesize this review, the literature in psychology and medicine was analyzed for the purpose of elucidating various biases and describing their relevance in dental practice. Results: Several cognitive biases were found to be relevant for diagnostics, decision making, treatment and practice management: the tailored framing of the communication content changes the perception of risks and influences the placebo and nocebo effects. The status quo bias may explain why patients tend to avoid undergoing reasonable treatment due to loss aversion. Affect heuristics shows the dependence of decision making on current emotions, which are rarely beneficial for the patient. Both the confirmation bias and attribution error affect diagnostics; facts supporting the initial diagnosis are given preferential consideration and the symptoms of patients who are perceived as difficult characters may be ignored or conveniently classified as psycho-somatic. The anchoring effect demonstrates why initial information has a disproportionate influence on the diagnosis. The overconfidence bias results in the practitioner's distorted self-perception, which can result in errors in diagnostics and therapy. Priming can direct the patient's perception towards a more positive outcome. The peak-end rule states that the recollection of a treatment is mainly influenced by the most aversive and final stimulus. The hindsight and outcome biases illustrate the tendency to remember a past experience in a distorted manner after events occur, thus underlining the importance of detailed patient records. The perception of the dentist's competence depends not only on dental skills, but due to the halo and nocebo effects, also on the environment, circumstances and style of communication. Discussion and conclusion: Cognitive biases affect both patients and dentists and this leads to errors in diagnostics, decision making and treatment. Dentists can try to use debiasing strategies in order to reduce those effects. Visual images such as pie charts and bar graphs help to reduce the effects of framing, especially in patients who are not mathematically inclined. The strategic use of cognitive biases by practitioners can be used to direct patients' perceptions towards more positive treatment experiences. Schlagwörter: biases, decision making, diagnostics, heuristics, practice management, psychology, treatment