Vibration perception thresholds of human vital and nonvital maxillary incisors

Vibrations applied to human teeth have been shown to induce vibrotactile sensations although the location of the mechanoreceptors responsible for encoding vibrations is unclear. The aim of this study is to test the hypothesis that vibrotactile tooth sensations depend on afferent input from intradental mechanoreceptors.

Vibration perception thresholds were determined for a vital (control) and a contralateral nonvital (endodontically treated) maxillary incisor in 11 healthy human participants using an adaptive psychophysical procedure. An electromechanical vibrator was used to deliver sinusoidal vibrations at 10 frequencies between 40 and 315 Hz.

The median force thresholds ranged between 41 and 215 mN for vital and 71 and 507 mN for nonvital incisors. Nonvital median force thresholds were significantly higher than vital thresholds at all frequencies between 40 and 315 Hz. A linear regression analysis revealed a significant increase in vibrotactile thresholds with increasing frequency for only the vital incisors.

The results support the hypothesis that mechanoreceptors located within the tooth contribute to vibrotactile tooth sensations and that mechanosensory information from both periodontal ligament and intradental mechanoreceptors facilitates the accurate assessment of food textures during mastication.