Role of Palatal Rugae in Speech Rehabilitation of Complete Denture Patients: A Comparative Spectrographic Study

Abstract

Background:
Speech performance is an important determinant of functional success and patient satisfaction following  complete denture rehabilitation. Palatal rugae present in natural dentition serve as tactile and positional guides for the tongue placement during articulation of linguopalatal sounds. Conventional dentures often lack this anatomical reference, potentially impairing phonetics. Incorporation of reproduced palatal rugae into complete dentures may improve phonetic performance and speech adaptation.

Aim:
To evaluate and compare phonetic performance in completely edentulous patients wearing dentures with and without palatal rugae using spectrographic analysis and subjective assessment.

Materials and Methods:

This prospective clinical study was conducted on 21 completely edentulous patients rehabilitated with complete dentures. Each participant was evaluated under three conditions: (1) no denture, (2) complete denture with characterized palatal rugae, and (3) complete denture without rugae. Speech recordings were obtained in a controlled environment using a standardized microphone setup (44.1 kHz, 16-bit). Phonetic stimuli were derived from a validated Hindi articulation test, and linguopalatal phonemes /t/ and /d/ were assessed in different word positions. Acoustic analysis was performed using Praat software to evaluate spectrographic clarity and articulation duration. Additionally, perceptual speech assessment was conducted by two independent speech-language pathologists blinded to the study conditions. Subjective evaluation was also performed using a visual analogue scale (VAS) for speech clarity, ease, and satisfaction.

Results:
Dentures incorporating palatal rugae demonstrated significantly improved phonetic outcomes. Spectrographic clarity increased from 68 ± 12 to 92 ± 10 for /t/ and from 71 ± 14 to 95 ± 12 for /d/ (p < 0.001). Articulation duration was significantly reduced, and patient-reported speech outcomes were significantly improved. Perceptual evaluation revealed enhanced articulation accuracy and reduced slurring in the rugae group. VAS scores for speech clarity, ease, and overall satisfaction were also highest with rugae-incorporated dentures.

Conclusion:
Incorporation of palatal rugae in maxillary complete dentures was associated with improved phonetic outcomes, enhanced clarity and ease of speech, reduced slurring, and improved patient satisfaction. This simple modification should be considered an important adjunct in denture design to optimize speech performance.