Abstract:

Objective To compare the treatment effect on the prominence of profile in borderline cases between extraction and non-extraction treatment. Methods The sample consisting of 33 borderline cases based on the judgment of 5 orthodontic special ists was divided into three groups according to the treatment way selected 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. Stricture superimposition was used to measure landmarks displacements which reflect the change of profile prominence before and after orth odontic treatment using pretreatment mplane as a frame of reference. Results Only the prominence of upper and lower incisors showed statistically significance between the extraction and non-extraction treatments. There~no statistically significant differ- ence between the extraction of four first premolars and second premolars. Conclusion The main effect of extraction vs. non-ex- traction 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.

Key words: borderline cases, extraction treatment, non-extraction treatment, prominence of profile