Oral Implant-Prostheses: New Teeth for a Brighter Brain

PLoS One. 2016 Feb 26;11(2):e0148715. doi: 10.1371/journal.pone.0148715. eCollection 2016.


Several studies have demonstrated that chewing can be regarded as a preventive measure for cognitive impairment, whereas masticatory deficiency, associated with soft-diet feeding, is a risk factor for the development of dementia. At present the link between orofacial sensorimotor activity and cognitive functions is unknown. In subjects with unilateral molar loss we have shown asymmetries in both pupil size and masticatory muscles electromyographic (EMG) activity during clenching: the molar less side was characterized by a lower EMG activity and a smaller pupil. Since implant-prostheses, greatly reduced both the asymmetry in EMG activity and in pupil's size, trigeminal unbalance, leading to unbalance in the activity of the Locus Coeruleus (LC), may be responsible for the pupil's asymmetry. According to the findings obtained in animal models, we propose that the different activity of the right and left LC may induce an asymmetry in brain activity, thus leading to cognitive impairment. According to this hypothesis, prostheses improved the performance in a complex sensorimotor task and increased the mydriasis associated with haptic tasks. In conclusion, the present study indicates that the implant-prosthesis therapy, which reduces the unbalance of trigeminal proprioceptive afferents and the asymmetry in pupil's size, may improve arousal, boosting performance in a complex sensorimotor task.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Animals
  • Anisocoria / etiology
  • Anisocoria / physiopathology
  • Anisocoria / psychology
  • Case-Control Studies
  • Cognition / physiology*
  • Dental Implants*
  • Electromyography
  • Female
  • Humans
  • Male
  • Masseter Muscle / physiology
  • Mastication / physiology*
  • Middle Aged
  • Molar
  • Mydriasis / etiology
  • Mydriasis / physiopathology
  • Mydriasis / psychology
  • Psychomotor Performance / physiology
  • Tooth Loss / physiopathology
  • Tooth Loss / psychology
  • Tooth Loss / surgery


  • Dental Implants

Grants and funding

The research was supported by grants of the University of Pisa, Iacer Company and Implafavourite Company. The contribution of the GB Bietti Foundation, IRCCS, was supported by Italian Ministry of Health and by Fondazione Roma. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.