Impact of Aesthetic Restoration on /s/ Acoustic Characteristics and Mandibular Speech Movements: A Case Series

Aim: This study aimed to evaluate the impact of different incisor overlaps on the acoustic characteristics of the /s/ sound and mandibular speech movement trajectory in patients undergoing anterior aesthetic restoration. Materials and Methods: Eight patients requiring bilateral upper incisor restorations were selected, all with normal occlusion and no other oral or speech-related conditions. Each patient received five different prostheses: (a) P0: Original overlap; (b) P1, P2, P3: Overjets of 1 mm, 2 mm, and 3 mm, respectively; (c) Pf: Final prosthesis designed for both aesthetics and function. Acoustic characteristics of the /s/ sound (fricative length, mean intensity, center of gravity, and noise peak) and mandibular speech movements were recorded and analyzed before and after restoration. Results: Restoration-induced overlap changes influenced /s/ acoustic features and mandibular speech movement. Notably, the noise peak decreased significantly by 11–23% and maximum closing speed reduced by 19–34% compared to individual normal occlusion (INO) values (P <.05). A correlation was observed between incisor overlaps and alterations in /s/ pronunciation and speech movement. Conclusions: Anterior aesthetic restorations can alter incisor overlaps, potentially affecting speech clarity by modifying /s/ acoustic characteristics and mandibular movements. Clinicians should carefully design overlaps to minimize speech disturbances, ensuring a balance between aesthetics, occlusion, and phonetics for optimal patient outcomes.