INFLUENCE OF DENTURE PALATAL CONTOURING ON THE OROPHARYNGEAL SPACE IN COMPLETE DENTURE WEARERS: A CROSS-OVER RADIOGRAPHIC STUDY

Objectives: The aim of this 2years cross-over study was to radiographically compare the influence of palatal contouring of maxillary denture on oro-pharyngeal airway space. Methods: The study was conducted on 20 healthy patients who were completely edentulous in the maxilla and mandible. All patients were randomly allocated in two equal groups to receive a mandibular denture opposed by a maxillary denture with either an arbitrary contoured palate (ACP) or a functional contoured palate (FCP) at the start of the study. The maxillary denture was exchanged after 1 year from insertion. The oropharyngeal volume (OPV) and minimum cross sectional area (CSA) were measured by using CBCT. Results: After 12 months of denture insertion, the mean OPV was more with FCP (29.9±3.1cm3) compared to ACP denture (24.9±2.2 cm3), also the mean CSA was more with FCP denture (363.7±67.3mm2) compared to ACP denture (286.5±65.8mm2). There was a high positive correlation between OPV and CSA with FCP denture ( r=0.90) and ACP denture (r= 0.61). Conclusion: Within this limited study, fabricating a complete denture with functionally contoured palatal surface may have a positive role in maintaining the oropharyngeal airway patency especially in old patients. (1598) Abdel-Khalek, et al. E.D. J. Vol. 64, No. 2 pharyngeal space may be reversible by complete denture insertion (5). Functionally, the genioglossus activity is well maintained in normal individuals during wakefulness as well as while asleep (4). Complete denture prosthesis restores an acceptable degree of masticatory function, improves phonetics, and provides esthetics by restoring both adequate support to orofacial musculatures and proper vertical dimension of the face (6). Additionally, wearing denture induces modifications in the position of the tongue and favors the patency of upper airway space especially in patients with sleep disorders (7). Indeed, insertion of an intraoral prosthesis would have an indirect effect on the tongue, soft palate, and the patency of the airway (8,9,10). The study of Gagnon et al. (11) on dentate patients, advocated that a bite elevation without a protrusive component might due to the risk of aggravating the upper airway obstruction for some patients. In this concern, Nayar and Knox (12) reported that complete dentures fabricated with an acceptable occlusal vertical dimension might not change the horizontal mandibular position in denture wearers. Emami et al. (2) found that edentulous elderly with poor sleep quality suffered from low oral health quality of life independent of nocturnal prosthesis wearing. Impaired function of the genioglossus muscles and pharyngeal inflammation was reported also with dentures wearing (6,13). Literatures stated that both the lingual flange and palatal plate are responsible for the encroachment of the tongue and reduction in upper airway volume (10,14). Furthermore, the shape of the palatal contour may affect the functions of the tongue and soft palate that will alter the pharyngeal airway volume (7). According to previous studies, the change in pharyngeal airway space may be a result of concentric collapse of the hypopharynx or collapsed lateral oropharyngeal walls, tongue, and soft palate against the posterior wall of the pharynx (5,15). Cephalometric radiography method that generates two-dimensional images may not valid for assessment of three-dimensional structures (16). Therefore, several studies assessed the airway volume by using 3D segmentation of Cone Beam Computed Tomography (CBCT) images (16,17,18). There was a limited data regarding the influence of palatal contouring of complete denture on these measurements in patients free from sleep disorders. The aim of this 2-years study was to compare the influence of palatal contouring of maxillary denture on oro-pharyngeal space volume (OPV) and minimal cross sectional area (CSA) using CBCT in normal healthy complete denture wearers. The null hypothesis of this study was that there is no significant difference in the oro-pharyngeal airway space regardless the palatal contour of the denture. MATERIALS AND METHODS