The most common congenital developmental disorder of the dentition is tooth agenesis, which is classified as hypodontia, oligodontia or anodontia, depending on the number of missing teeth. This anomaly can occur as an isolated defect or as one of the symptoms of complex genetic syndromes. Prosthodontic treatment of adolescent patients with congenital absence of multiple permanent tooth germs requires multistage interdisciplinary management in cooperation with specialists from other dental disciplines like orthodontics, oral surgery and paedodontics. Prosthetic rehabilitation at each developmental stage should be carried out in such a way as to ensure the correct development and function of the stomatognathic system. Prosthetic restorations should be checked and replaced periodically so as not to inhibit growth processes. An additional difficulty when treating oligodontic patients is the condition of the prosthetic base: frequently significant underdevelopment of the alveolar processes in edentulous segments and the atypical structure of the retained teeth. The aim of this study is to present two cases of prosthetic treatment of patients with oligodontia at a developmental age: a 15-year-old patient with idiopathic congenital absence of permanent tooth germs and an 11-year-old diagnosed with ectodermal dysplasia. Due to the intensive development of the masticatory organ acrylic removable temporary overdentures were fabricated. The treatment significantly improved the patients’ masticatory and speech functions and overall facial aesthetics.