Nasal function in patients with maxillectomy using various obturator designs

Maxillary obturators have been used to restore oral tissues, extending into the defective nose for sealing and retention. Although they markedly improve oral health-related quality of life, the effects of maxillectomy and obturators on nasal function have not been thoroughly investigated.

The purpose of this computational study was to evaluate the effect of a maxillectomy procedure for cancer on the nasal function by considering variables related to nasal physiology and clinical symptoms, including relative humidity and temperature.

The effects of a maxillectomy on nasal function were simulated by using computational fluid dynamics simulation, both without an obturator and with various obturator designs. The computed tomography data of 10 patients with a maxillectomy were used to create maxillectomy-without-obturator (MWO) airway models. Obturators were fabricated, and modified to align with copies of MWO models, creating maxillectomy-with-closed-bulb-obturator (MCO) and maxillectomy-with-open-bulb-obturator (MOO) models. Additionally, 10 models were created from 10 healthy individuals as a control. An inspiration cycle of 1.9 seconds was simulated. Statistical tests were used to evaluate the differences between groups (α=.05).

On the normal sides, airflow exhibited laminar flow comparable with that of the control group, whereas the defect sides displayed vortices of various sizes, depending on the obturator design. A maxillectomy significantly affected air properties at the nasopharynx, with a notable decrease in temperature (P=.007) and relative humidity (P<.001). The obturator groups exhibited a significant reduction in tidal volume (P=.007 for both groups) and airflow velocity (P=.009 for MCO and P=.007 for MOO). Additionally, inspired air temperature at the nasopharynx significantly increased (P=.005), and wall-shear stress contours were altered compared with the MWO group. However, no significant changes in relative humidity were observed (P>.05). The obturator groups showed no significant differences from the control group, except for relative humidity (P<.001).

A maxillectomy was found to significantly alter nasal airflow dynamics, leading to changes in temperature, relative humidity, and wall-shear stress. The use of obturators partially restored airflow characteristics, reducing velocity and tidal volume while increasing inspired air temperature. However, obturators did not fully normalize nasal humidity levels. These findings highlight the impact of maxillary defects and prosthetic interventions on nasal physiology, emphasizing the need to optimize obturator design to improve nasal function after a maxillectomy.