In medicine, as a rule, a dentist’s opinion, behavior, and symptom assessment are distinguished by subjectivity. From this point of view, medical information is characterized by bimodal information, which is caused by the subjectivity of human thoughts. Information about diseases is usually imperfect, which is usually caused by probabilistic and fuzzy types of uncertainty. The accuracy of early data is crucial in determining the most appropriate treatment strategy for a dental illness. The Z-number-based approach is the most accurate technique to characterize bimodal data. In this study, we show the application of this approach in choosing the most effective therapy for periodontitis, a common dental illness. Depending on the illness's progression and symptoms, we assess several therapy options. States of illness and the related values of treatment methods are evaluated by a dentist using linguistic terms. The effectiveness of treatment methods is determined by using a Z-number-based calculation. The collected outcomes are compared based on the degree of optimality, and the most efficient treatment strategy is selected.