THE INCIDENCE OF ORAL CLEFTS - A REVIEW

We have reviewed epidemiological studies on the incidence of oral clef ts in several regions of the world, but mainly in Europe, The incidenc e ranges from 1.0/1000 to 2.21/1000, The highest incidence was in Czec hoslovakia (1.81/1000), followed by France (1.75/1000), Finland (1.74/ 1000), Denmark (1.69/1000), Belgium and the Netherlands (1.37/1000), I taly (1.33/1000), California (1.12/1000) and South America (1.0/1000), The data from Denmark and Finland appeared to be the most reliable. A ll studies showed a higher incidence of cleft lip and/or palate (CL(P) ) compared with cleft palate (CP). There was a predominance of girls i n the CP group, while the CL(P) group comprised mainly boys, The left side was affected twice as often as the right side, Black children had a lower incidence than white children, An attempt was made in several reports to clarify the cause of oral clefts, but opinions are contrad ictory.