Investigating the maximum bite force and speech intelligibility in patients requiring prosthetic rehabilitation

Tooth loss leads to reduced occlusal contact area, altered jaw biomechanics, and diminished neuromuscular coordination, impairing both masticatory function and speech clarity. Edentulous patients often adapt by modifying food choices or swallowing behavior and may experience persistent phonetic disturbances. Maximum bite force affects masticatory performance, while speech intelligibility affects patient communication. This study aimed to objectively evaluate maximum bite force and speech intelligence among completely edentulous patients rehabilitated with different types of prostheses, compared with natural dentition.

A cross-sectional study (IRB #857207) was conducted with 50 participants divided into 5 groups: (A) implant-supported fixed dental prosthesis (IFDP); (B) implant-retained complete removable overdentures (IOD) in both arches; (C) maxillary complete removable dental prosthesis (CRDP) with mandibular IOD; (D) maxillary and mandibular CRDP; and (E) natural dentition (control). Maximum bite force was measured using a microelectromechanical (MEM) pressure sensor during three maximal-effort bites; unilateral values were also analyzed. Speech intelligence was assessed using a standardized articulation passage and analyzed with a speech intelligibility scorer; readings were taken three times per participant.

Group E had the highest masticatory bite force (752.03 N), followed by Groups A (522.97N), B (294.13 N), C (174.23 N), and D (72.13 N). Total bite force was 1.5-1.8× greater than unilateral values. Group E also had the highest speech score (85.67%) and outperformed Groups B, C, and D (p < 0.005). Fixed prostheses and natural dentition (Groups A and E) outperformed removable designs (Groups B, C, and D) in both maximum bite force and speech intelligibility. Males had higher bite force than females (p < 0.01); no statistically significant gender differences were found for speech.

This study underscores the need for individualized assessment strategies in prosthodontic rehabilitation by establishing an objective functional gradient across prosthetic designs. Complete removable dentures exhibited only one-tenth of the maximum bite force of natural dentition. Maximum bite force improved to 2.4× with a mandibular IOD and 4× with IOD in both arches. Fixed prostheses yielded superior speech intelligibility due to enhanced tongue space and palatal contours. Total bite force was consistently greater than unilateral values. While gender influenced bite force, it did not affect speech. Bite force sensors and intelligibility scorers offer efficient, evidence-based tools for long-term evaluation.