[The dentition and jaw growth of 60 mono- and dizygotic twins between the ages of 10 and 18].

60 twins were investigated between the age of ten and 18 years to obtain information about inheritance of tooth-crown size and growth of alveolar bone. The results suggest genetically controlled interaction between tooth germs during their formation. The intrapair differences decrease between ten and 18 years for the alveolar bone diameters. This is an advise for stronger genetically influences in higher age and an etiological factor for relapse after orthodontic treatment.