Objective To 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.Results There was statistical significance between digitsucking 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（PConclusionThe 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.
