Among rare diseases, a fifth of them are associated with oral manifestations. The most frequent are: enamel dysplasia, cleft lip or palate and oligodontia. Beside the pathology, patients are eager of functional therapeutics which often needs prosthodontics. This oral rehabilitation aims to a better life quality.

Teeth absence management in the case of oligodontia necessitates critical analysis of the supporting tissues: the periodontium and the underlying bone. Deciduous teeth with resorbed roots and hypoplasic permanent teeth are often observed. Thus, some questions arise: can we use them as abutments or can we restore them knowing that they present an anomaly in their position and are more fragile? How do we replace many teeth when bone is lacking (clefts, agenesis)? Can we implant on a missing tooth site or can we use autograft? What do we expect for periodontal healing?

Adjacent teeth have often migrated, occlusion is unstable due to mixed dentition and patient’s disease. For example, in mandibular incisors agenesis cases, the remaining deciduous teeth are used when consultation happens at adolescence. This results in upper jaw incisors migration toward mandible and thus an anterior overbite. Orthodontic treatments will allow to recreate gap width and a normal occlusion in order to perform prosthodontics treatment in the best possible conditions. Giving the weak dental and periodontal supports, our attention will be focused on choosing the best option between tooth and implant supported prosthodontics. During the mixed dentition, orthodontic treatment and aesthetic rehabilitation have to be planed at the same time and to last until “definitive” implant and periodontal therapies are possible. In this article, we will present one oligodontia case report to illustrate a possible solution.