Dental twinning can result from the fusion of the developing dental germinal elements or the gemination of a single germ. In bilateral anterior and posterior dental twinning, problems such as poor esthetics, dental caries, arch-length problems, and periodontal disease often occur as a result of the irregular morphology. Several treatment methods have been described in the literature with respect to the different types and morphologic variations of twinned teeth, including endodontic, restorative, surgical, periodontal, and orthodontic treatment. This report documents the case of a young patient with an exceedingly rare phenomenon of permanent twinned teeth and multiple supernumerary teeth in both sides of the mandibular and maxillary arches, as a result of combined fusion and gemination. Palabras clave: fusion, gemination, supernumerary teeth, twinned teeth