Related Experiment Video
Updated: Feb 6, 2026

Ultrasound Images of the Tongue: A Tutorial for Assessment and Remediation of Speech Sound Errors
Published on: January 3, 2017
Influence of Oral Morphology on Speech Production in Subjects Wearing Maxillary Removable Partial Dentures with Major
Junichiro Wada1, Masayuki Hideshima2, Shusuke Inukai1
1Section of Removable Partial Prosthodontics, Department of Masticatory Function Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
Background/Aims:
Speech impairment during the initial phase of removable partial denture (RPD) treatment can prevent patient adaptation to RPDs. This study was undertaken to investigate the influence of oral morphology on speech production in subjects wearing RPDs with major connectors.
Methods:
Two types of connectors were fabricated for 17 subjects with normal dentitions: covering the middle palate (M-bar) and the anterior/posterior palate (AP-bar). Four target sounds ([∫i], [t∫i], [çi], and [ki]) were evaluated under 3 recording conditions: no connector, M-bar, and AP-bar. The mean appearance ratios of correct labels (MARCs) were calculated as parameters representing speech production accuracy with the speech evaluation system. Subgroup analysis was conducted based on palate height, dental arch width, and front space volume of the oral cavity.
Results:
Based on the multiple linear regression test, a significant association was found between the MARCs of [∫i] with M-bar and front space (p = 0.036). In the subgroup analysis, the AP-bar had a significant effect on the MARCs of [∫i] among subjects with high palate (p = 0.026), narrow arch (p = 0.004), and small front space (p = 0.014).
Conclusion:
RPDs with major connectors could disturb speech production among patients with high palates, narrow arches, and small front spaces.
Related Concept Videos
Biopharmaceutical Factors Influencing Drug Product Design: Overview
Partial Fractions
Major Organs of the Digestive System
Gastrointestinal tract:
Major Hormones and Their Functions
Oxytocin, produced in the hypothalamus and released by the pituitary gland, plays a role in social bonding, childbirth, and...
Major Losses in Pipes
Fluid flow can be classified as laminar or turbulent, primarily based on the Reynolds number. This dimensionless number reflects the relative influence of inertial to viscous...
Mixtures of Gases: Dalton's Law of Partial Pressures and Mole Fractions

