Effect of first premolar extraction on nasal airway dimension in adult bimaxillary dento-alveolar protrusion patients – a retrospective cephalometric study

Aim: First premolar extraction is the treatment option usually for bimaxillarydento-alveolar protrusion patients. Tongue space and length tends to be reduced after the retraction of anteriors and thus this study was done to determine the effects of first premolar extraction and retraction of the anteriors on the upper airway dimension. Materials and Methods: This retrospective study was carried out on the available pre- and post-orthodontic treatment records of adult patients who had bimaxillarydento-alveolar protrusion. The study material consisted of 31 patients with bimaxillarydento-alveolar protrusion and underwent fixed orthodontic treatment with extraction of upper and lower first premolar teeth. Digitized cephalometric radiographs were used to measure airway dimensions with the help of Dolphin 2d software. A paired t-test was used to compare the effects at p<0.5. Results: Results showed significant reduction in tongue length (p<0.5), Superior, middle and inferior airway space. SNA, SNB, ANB, Inter-incisal angle, Wits appraisal, Lower incisor Protrusion and Upper incisor – Palatal plane showed significant changes. Conclusion: Even though there is statistically significant airway reduction, it is clinically non-significant. Unless the airway is severely compromised, first premolar extraction and retraction of anteriors does not greatly affect the airway dimensions.