Influence of orthodontic treatment with first premolar extraction on the angulation of the mandibular third molar

OBJECTIVE: To evaluate the influence of orthodontic treatment that involved first premolars extraction on the angulation of the developing mandibular third molars, and whether this will result in an improvement in it's path of eruption during tooth development.

METHODS: A cross-sectional radiographic study was conducted using 80 panoramic radiographs of 40 orthodontic patients previously treated at the College of Dentistry, King Saud University, Riyadh, Kingdom of Saudi Arabia. The sample consisted of 2 groups, extraction and non-extraction orthodontic therapy group with equal number of patients in each group. The orthodontic treatment of the extraction group involved the extraction of first premolars, whilst non-extraction group had received orthodontic therapy without teeth extraction. The angulation of the right and left third mandibular molars was measured in each patient separately, and the data was analyzed using the non-parametric Mann-Whitney Test.

RESULTS: The present data has shown significant improvement in the third molars angulation in the extraction orthodontic therapy group compared to non-extraction group, Although this finding was significant in both genders, females tend to show better response in the improvement of third molar angulation to extraction therapy than males (p=0.001, p=0.006).

CONCLUSION: Orthodontic treatment with first premolars extraction has improved the third molars angulation during their course of eruptions and consequently supports the decision of the orthodontic extraction therapy approach in borderline cases.