OBJECTIVETo investigate the influence of digit-sucking habit on palatal features in pre-school children by using a laser scanning system.

METHODSForty pre-school children were chosen according to the results of questionnaires, among which 20 with digit-sucking habit(digit-sucking group) and 20 without any oral habits(control group). Impression of the upper jaw was taken from each child. After laser scanning the plaster casts, and three-dimensional reconstruction by the computer, parameters of anterior and posterior palatal length, width and height were measured, ratios of height/width, length/width and width ratio of anterior and posterior palatal were analyzed. The differences of palatal features between two groups were analyzed by t test.

RESULTSThere was statistical significance between digit-sucking group and control group in posterior palatal width, anterior palatal length and anterior palatal height. The ratios of height/width and length/width in both posterior and anterior areas were statistically significant (P < 0.05). Compared to the control group, the results indicated that palatal features were relatively deeper, narrower and more protrusive in digit-sucking group.

CONCLUSIONThe digit-sucking habit may have some deleterious impacts on the palatal features in pre-school children with primary dentition. And it is practical to measure the spacial palatal features by using laser scanning system to some extent.