Bite force displayed during assessment of hardness in various texture contexts

How people perceive food hardness remains unclear despite known adjustments in chewing behavior. Mastication patterns change with food texture, but the exact mechanisms are not fully understood. Prior research has shown that texture perception involves sensory feedback during chewing. However, the role of bite force in this process is still debated. This gap motivated a closer look at how bite force influences hardness perception. No prior work had resolved whether bite force directly correlates with perceived hardness. Different food types—elastic, plastic, and brittle—may trigger distinct sensory responses. This study aimed to clarify these relationships by testing various materials with known mechanical properties.

This research aimed to explore how bite force relates to perceived hardness in different material types. The specific problem addressed was the lack of clarity about sensory mechanisms in hardness assessment. The motivation came from the need to better understand oral sensory feedback during chewing. The study focused on three material categories: elastic, plastic, and brittle. Each material type was chosen for its distinct mechanical properties. The goal was to determine if bite force correlates with perceived hardness. The study also sought to compare sensory responses across different bite conditions. By measuring bite force and hardness thresholds, the researchers aimed to identify patterns in sensory perception.

The study used elastic, plastic, and brittle materials with known mechanical properties. These included silicone elastomers, waxes, and pharmaceutical tablets. Rheological characteristics of each material were measured to establish baseline properties. Ten individuals free of dental issues participated in the study. Bite forces were recorded using intraoral load cells placed under each sample. Participants assessed hardness thresholds at multiple points on a hardness scale. Bites were made either directly on the sample or through a metal disc placed between teeth and sample. This setup allowed comparison of sensory feedback under different force conditions.

Bite forces showed a strong correlation with perceived hardness in brittle materials (r = 0.99). For plastic materials, the correlation was also high (r = 0.96). Participants could stop biting during plastic deformation, yet bite force remained linked to hardness perception. Elastic materials did not show the same force correlation. Instead, hardness perception for elastic products occurred under constant bite force. Deformation of elastic materials may provide sensory feedback about hardness. The use of a metal disc altered bite force patterns but did not eliminate the correlation. These findings suggest that sensory feedback from bite force is critical for hardness perception in brittle and plastic materials.

The authors suggest that bite force directly influences hardness perception for brittle and plastic products. Sensory feedback from bite force appears to be essential for these materials. Elastic materials, however, may rely on deformation rather than bite force for hardness perception. The study supports the idea that sensory information about bite force is crucial in certain contexts. No prior work had resolved this distinction between material types. The results align with the hypothesis that sensory mechanisms vary by material type. The authors propose that further research should explore how deformation contributes to hardness perception. These findings may inform future studies on oral sensory processing and food texture perception.