RESUMO
Abstract The object of this study was to compare the clinical complications of 4 different appliances used in the early treatment of anterior open bite (AOB), and to test the null hypothesis that there is no difference in the number of complications among the appliances. Records from 99 Class I malocclusion patients with AOB treated using bonded spurs, BS, n = 25; chin cup, CC, n = 25; fixed palatal crib, FPC, n = 25; and removable palatal crib, RPC, n = 24) were examined. The total number and frequency of clinical complications that occurred over 12 months were described and compared by using chi-square and Kruskal-Wallis tests (Dunn's post-test) (α = 5%, CI = 95%). The incidence of clinical complications was 66.7%, comprising: breakage, bond failure, maladjustment, allergy, soft-tissue lesion, loss of removable appliance and abandonment. Eighteen patients gave up treatment; this occurred more frequently in the groups with removable appliances. Regarding the total number of complications per patient, Group BS exhibited a significantly higher number than the other groups (p < 0.0001). A low frequency of complications (1 to 3) was found in the groups, except for Group BS, in which 8% of the patients presented moderate frequency (4 to 6). In terms of appliance types (fixed or removable), there was no difference in the incidence of complications (p > 0.094). The null hypothesis was rejected, since the BS group exhibited the highest total number and frequency of complications. There was no difference between fixed and removable appliances in terms of incidence of clinical complications, although more patients using removable appliances abandoned their treatment.