Overjet and overbite distribution and correlation: a comparative epidemiological English-Iraqi study

There have been no widely used criteria and methods of measurement for evaluating the incisor relationship in terms of overjet and overbite and, therefore, no widely accepted definition of their normal values. A simple, efficient, metric overbite and overjet gauge has been developed and used on 236 English and 250 Iraqi samples. The normal range of overjet and overbite is considered as 2-4 mm. The English variation tends towards increased overjet and overbite, while the Iraqi variation tends towards lower values for both parameters. Significant correlation is seen between overjet and overbite at 1 per cent level in both samples.