Introduction: Improving masticatory and postural function is one of the primary
goals of orthodontic treatment. The assessment of the patient's occlusion throughout
the treatment permits the orthodontist to improve the functional occlusion through
interventional tooth movements when necessary, rendering the overall treatment to be
more efficient and decreasing the patient's discomfort. Aim: An in-vivo cross-sectional
study to evaluate the effect of upper first premolars extraction during orthodontic
treatment on bite force distribution. Methods: Ten patients (mean age=16.13±2.17
years), who would be treated orthodontically with upper first premolars extraction to
treat their upper anterior teeth proclination, were selected for this study. The T-scan
III system was utilized to measure the occlusal bite force of the patients before and
after treatment, and the findings were compared. Results: There was a statistically
significant increase in the occlusal bite force's mean in the arch's anterior segment from
5.96% (±6.57) to 14.48% (±8.81) after the orthodontic treatment. A non-statistically
significant increase in the occlusal bite force in the posterior right segment of the
arch from 36.94% (±15.60) to 42.36 % (±11.14) was found after the treatment. The
occlusal bite force in the posterior left segment of the arch decreased insignificantly
from 56.45% (±15.72) to 40.15% (±13.59). It was found that there was an increase in
the distribution of occlusal bite force on the right side and a subsequent decrease on the
left side after treatment. There was an even distribution of bite force on both sides of the
arch by the end of the treatment. Conclusions: Extraction of upper first premolar teeth
does not negatively impact the functional aspect of occlusion. The T-scan III system is
a key diagnostic tool utilized during orthodontic treatment to monitor occlusal changes.