Hou G L, Tsai C C
Aust Dent J. 1989 Jun;34(3):219-22. doi: 10.1111/j.1834-7819.1989.tb00672.x.
Fusion of teeth is most commonly reported in the deciduous dentition, particularly in the anterior teeth. Recently, additional cases of fusion have also been reported in the mandibular molars of the permanent dentition, and are not considered uncommon. However, reports of the involvement of maxillary molars appear to be particularly rare in the literature. This case is another example of the quite rare phenomenon of fusion of maxillary third and supernumerary fourth molars.