OBJECTIVE: To verify the amount of patients who had to undergo extraction of permanent teeth (premolars) in a population of patients treated with extraction of deciduous teeth for correction of incisor crowding in the mixed dentition, as well as to analyze the possibly related variables. METHODS: The sample was composed of orthodontic records of 70 patients in the permanent dentition whose treatment included the serial extraction program (SEP) in the mixed dentition. All records were analyzed by a single examiner in order to verify whether the SEP had been carried out with extraction of either permanent teeth or deciduous teeth only. The association between extraction of permanent teeth and the variables lateral facial pattern, sagittal relationship between the dental arches, IMPA, proportion between size of the mandibular second molar/retromolar space, mechanics for spacing control and tooth-arch size discrepancy (exact test of Fisher for categorical variables and logistic regression for numeric variables, p<0.05) were investigated. RESULTS: Of the patients treated with extraction of deciduous teeth, 70% also needed extraction of the permanent teeth. The statistical analysis did not show any significant correlation between the variables analyzed and the need for extraction of permanent teeth, except for tooth-arch size discrepancy. CONCLUSION: Tooth-arch size discrepancy represented the main factor that determined premolar extraction in the SEP.
Dentition; Mixed; Malocclusion; Serial extraction
