Comparison of dental arch dimensions in children from southern and northern Finland.

The purpose of this survey was to determine whether children in northern Finland had different dental arch dimensions from children in southern Finland. Dental casts of 9-year-old healthy children from Helsinki (southern Finland) and from Oulu and Sodankylä (northern Finland) were measured. Each group contained 41 subjects who had received no orthodontic treatment. The children from Sodankylä and Oulu had narrower dental arches and greater palatal heights than those from Helsinki. The lengths and perimeters of dental arches were significantly shorter in the children from Sodankylä than in those from Helsinki. We suggest these differences could have resulted from adaptation to different climatic conditions, affecting modes of breathing.