[From translation by Rudolf Kronfeld.]
Caries results from a complex of various conditions among which environmental factors, and structural inferiorities due to diseases of infancy, seem to play decisive roles. Coarse consistency of the diet, requiring special mastication, greatly increases resistance to caries, as shown by nutritional experiments with hard bread on orphans over a two-year period; and development of the dental arches is very favorably influenced by the ensuing increased functional stimulation. Numerous investigations of identical and non-identical twins failed to reveal an essential influence of hereditary factors in caries.
Further studies are being carried out on twins to determine whether, after exclusion of the most commonly affected first permanent molars, caries of the less commonly affected teeth and in atypical areas is caused by constitutional and thus essentially hereditary factors.
References: D. Zahnetrz. Woch., 1929; Kampf d. Karies (Zahniirz. Mitteil.), 1937; D. Med. Woch., 1937; Ann. Clin. Odontoiat., 1938.