Chewing with Co-Cr or PEEK denture frameworks: A randomized crossover clinical study

To compare masticatory function and patient satisfaction with removable partial dentures (RPDs) with cobalt-chromium (Co-Cr) and injected polyetheretherketone (PEEK) frameworks, respectively.

Twelve volunteers (7 women, 5 men; mean age, 56.6 years) with complete maxillary edentulism and partial mandibular edentulism (Kennedy Class I) first received new RPDs with PEEK (experimental group) or Co-Cr (control group) frameworks and used them for 2 months. Masticatory performance (MP) was evaluated using sieves and Optocal, with results expressed as the mean particle size (X₅₀); maximum bite force (MBF) was measured with a force transducer and pressure sensors; and self-reported satisfaction was assessed using a visual analog scale. After the initial evaluation, a 1-week washout period was followed by group crossover and reassessment after an additional 2 months. Data were analyzed using independent-samples t-tests (α = 5%).

X₅₀ values were lower for RPDs with Co-Cr frameworks than for those with PEEK frameworks (p = 0.007), indicating better MP. The MBF did not differ significantly between RPD framework types. Participants' satisfaction, in terms of prosthesis stability (p = 0.02) and chewing ability (p < 0.001), was greater for Co-Cr RPDs. Most participants preferred to continue using Co-Cr frameworks.

RPDs with injected PEEK frameworks were associated with reduced MP and patient satisfaction relative to Co-Cr frameworks.