The document discusses several anomalies and abnormalities that can occur in tooth formation and eruption. Supernumerary teeth are extra teeth that develop in addition to the normal number. Hypodontia is a congenital absence of one or more teeth. Abnormalities can also occur in tooth size, shape, structure and formation. Some examples provided include taurodontism, dens invaginatus, amelogenesis imperfecta and dentin dysplasia. Many conditions are genetic or due to disruptions during tooth development and may require monitoring or treatments like extractions or root canals.