RESUMO
<p><b>OBJECTIVE</b>To investigate the effect of different palatoplasty timing on the dental arch relationship between upper and lower jaws by a retrospective study.</p><p><b>METHODS</b>A total of 103 UCLP consecutive cases over 10 years of age were followed up after operation, which were divided into three groups according to the age of operation, group A: < or = 3.0-years-old, group B: < or = 6.0-years-old and group C: > 6.0-years-old above. Maxilla and mandible plaster casts were taken for each patient. Goslon Yardstick system was used for assessing the dental arch relationships between upper and lower jaws.</p><p><b>RESULTS</b>Goslon Yardstick assessing results showed that there was no significant difference between group A and group B (P>0.05), there was significant difference between group C and group A (P<0.05), and C was no significant difference between group B and group C (P=0.095).</p><p><b>CONCLUSIONS</b>Six-years-old was a boundary line on considering the influence of cleft palate operation age on the maxillary development. The Yardstick mean value became smaller along with increase of operation age.</p>