Numerical simulation and functional evaluation of upper airway before and after twin block treatment with different respiratory pathways.

OBJECTIVES

The aim of this study was to evaluate the changes of upper airway ventilation function in children with mandible retrognathia under different respiratory pathways after Twin Block (TB) using computational fluid dynamics (CFD).

MATERIALS AND

METHODS

This study included 20 patients with mandible retrognathia who underwent TB treatment, including 8 males and 12 females (age 10.67 ± 1.51 years). The airflow information obtained by using an oral and nasal thermistor was used as the boundary condition for CFD simulation to analyze the influence of different respiratory paths on upper airway flow.

RESULTS

After TB, the pressure drop, resistance, and shear force in the velopharynx (Vp) and glossopharynx (Gp) were significantly reduced during nasal breathing. Pearson correlation test showed that obstructive apnea index (OAI) was negatively correlated with the internal pressure of the upper airway, and positively correlated with the pressure drop, resistance, and maximum shear force of the upper airway, especially the velopharynx resistance, which showed a significant positive correlation. For patients with obvious oral breathing, the improvement of fluid dynamics parameters inside the glossopharyngeal region was more significant. The OAI was significantly positively correlated with the pressure drop and resistance in the glossopharynx region.

CONCLUSIONS

For different respiratory pathways, TB can improve the ventilation function of patients with mandible retrognathia.