Failure of Hertwig's epithelial sheath diaphragm to investigate the proper horizontal level leads to:
Taurodontism.
Dentin dysplasia.
Pulp polyp.
Amelogenesis imperfecta.
TAURODONTISM

Also called Bull-like teeth.
Originally described by Sir Arthur Keith in 1913 to describe a condition in which the body of the tooth is enlarged at the expense of roots.
Caused by the failure of Hertwig’s epithelial sheath diaphragm to investigate the proper horizontal level.