Palatogram Analysis of Complete Upper Denture Adaptation in Producing S and Z Sound: A Cohort Study

Introduction This study aimed to evaluate the contact area between the tongue and the intaglio surface of complete upper dentures during the production of the /s/ and /z/ phonemes using palatography. A secondary objective was to compare palatographic findings based on gender, age, and denture-wearing history. Methods A clinical cohort study was conducted on 40 subjects (20 males, 20 females) with complete upper dentures. Palatograms (zone A until X) were obtained by applying Pressure Indicator Paste to the dentures, instructing subjects to pronounce the ‘S’ and ‘Z’ phonemes, and photographing the resulting tongue-palate contact patterns over 60 days. Data were analyzed using t-tests. Results Significant differences in ‘S’ phonetics (zones B, C, F, and G) were observed across gender ( p = 0.003), age groups ( p = 0.024), and denture-wearing history ( p < 0.001). ‘Z’ phonetics (zones F, G, N, Q, T, and W) also showed significant differences in age groups ( p = 0.004) and denture-wearing history ( p < 0.001). Palatographic analysis identified specific contact zones for the /s/ and /z/ phonemes, with phonetic adaptation occurring predominantly between the second and third control visits. Discussion Phonetic disturbances, particularly involving the sibilant sounds /s/ and /z/, frequently occur following the insertion of complete upper dentures but typically improve within two weeks due to neuromotor tongue adaptation. This study found that female patients under 60 with prior denture experience adapted more effectively, and palatogram analysis revealed specific tongue-palate contact zones critical for accurate articulation. Conclusion Palatography proved to be a valuable clinical tool for assessing tongue–palate contact in complete upper denture wearers, particularly for the ‘S’ and ‘Z’ phonemes. The study highlights that optimal phonetic performance is influenced by gender, age, and prior denture experience, with adaptation occurring mainly between the second and third follow-up visits. This study highlights the importance of individualized denture adjustments in enhancing speech clarity and overall patient satisfaction.