Many of the temporomandibular joint (TMJ) disorders occur during growth. An early treatment would improve the life of the patients and avoid later surgical treatment [1]. Nowadays, TMJ treatments are exclusively performed from a clinical point of view. Finite elements (FE) models are not used due to the complex geometry of the TMJ and because the properties of the soft tissues are unknown [2]. Thus, the purpose of this study is multiple: 1. To diagnose the TMJ disorder in a child patient using FE analysis. 2. To characterize the behaviour of the tissues of the TMJ using porous-fibrous material models. 3. To numerically design a non-invasive treatment. 4. To clinically perform the designed treatment.