Table 1.

Prevalence of each type of malocclusion in Japanese children aged 4–6 years.

Occlusal Traits	4 Years Old	5 Years Old	6 Years Old	Total
	(n = 160)	(n = 217)	(n = 100)	(n = 477)
Sagittal relationship	28.8%	23.0%	36.0%	27.6%
Anterior crossbite	9.4%	6.9%	7.0%	7.7%
(mild/moderate)	(1.9%/7.5%)	(2.8%/4.1%)	(2.0%/5.0%)	(2.3%/5.5%)
Excessive overjet	19.4%	16.1%	29.0%	19.9%
Vertical relationship	26.9%	28.1%	28.0%	27.7%
Deep overbite	18.1%	22.1%	18.0%	19.9%
Anterior open bite	8.8%	6.0%	10.0%	7.8%
Transversal relationship	0%	0%	0%	0%
Posterior crossbite	0%	0%	0%	0%
Scissors bite	0%	0%	0%	0%
Space discrepancies
Crowding	10.0%	12.4%	9.0%	10.9%