OBJECTIVETo compare the treatment effect on the prominence of profile in borderline cases between extraction and non-extraction treatment.

METHODSThe sample consisting of 33 borderline cases based on the judgment of 5 orthodontic specialists was divided into three groups according to the treatment way selected by the doctor in charge of the case. Three groups comprised 12 non-extraction cases, 13 four first premolars extraction cases and 8 four second premolars extraction cases. Structure superimposition was used to measure landmarks displacements which reflect the change of profile prominence before and after orthodontic treatment using pretreatment FH plane as a frame of reference.

RESULTSOnly the prominence of upper and lower incisors showed statistically significance between the extraction and non-extraction treatments. There was no statistically significant difference between the extraction of four first premolars and second premolars.

CONCLUSIONThe main effect of extraction vs. non-extraction on profile of borderline cases is the prominence of upper and lower incisors, while their influences on upper and lower base bone and soft-tissue profile are not obvious.