The phenomenon of<unk>  arises through union of two normally separated<unk>  germs, and depending upon the stage of development of the teeth at the time of union, it may be either complete or incomplete. On some occasions, two independent pulp chambers and root canals can be seen. However,<unk>  can also be the union of a normal<unk>  bud to a supernumerary<unk>  germ. In these cases, the number of teeth is also normal and differentiation from<unk>  gemination may be very difficult, if not impossible. In geminated teeth, division is usually incomplete and results in a large<unk>  crown that has a single root and a single canal. Both gemination and<unk>  are prevalent in primary dentition, with incisors being more affected.<unk>  gemination, in contrast to<unk> , arises when two teeth develop from one<unk>  bud and, as a result, the patient has a larger<unk>  but a normal number.
Tooth fusion
Labial fusion
Brain zap
Achondrogenesis
Sensory decussation
Decussation of the pyramids
Vascular ring
Hypoplasia