Improved Prefrontal Activity and Chewing Performance as Function of Wearing Denture in Partially Edentulous Elderly Individuals: Functional Near-Infrared Spectroscopy Study

Abstract

The purpose of this study was to elucidate the effects of wearing a denture on prefrontal activity during chewing performance. We specifically examined that activity in 12 elderly edentulous subjects [63.1±6.1 years old (mean ± SD)] and 12 young healthy controls (22.1±2.3 years old) using functional near-infrared spectroscopy (fNIRS) in order to evaluate the quality of prefrontal functionality during chewing performance under the conditions of wearing a denture and tooth loss, and then compared the findings with those of young healthy controls. fNIRS and electromyography were used simultaneously to detect prefrontal and masticatory muscle activities during chewing, while occlusal force and masticatory score were also examined by use of a food intake questionnaire. A significant increase in prefrontal activity was observed during chewing while wearing a denture, which was accompanied by increased masticatory muscle activity, occlusal force, and masticatory score, as compared with the tooth loss condition. Prefrontal activation during chewing while wearing a denture in the elderly subjects was not much different from that in the young controls. In contrast, tooth loss in the elderly group resulted in marked prefrontal deactivation, accompanied by decreased masticatory muscle activity, occlusal force, and masticatory score, as compared with the young controls. We concluded that intrinsic prefrontal activation during chewing with a denture may prevent prefrontal depression induced by tooth loss in elderly edentulous patients.

Mastication as a protective factor of the cognitive decline in adults: A qualitative systematic review

“…Other authors, such as Yokoyama et al ,. using near‐infrared spectroscopy, pointed out the relation between mastication and cerebral oxygenation, just as Kamiya et al . reported the effects of dental prostheses on the activity of the PFC during mastication.…”

“…Thus, a greater number of participants are needed to assess the importance of all variables. Activation of cerebral activity was found to increase significantly in the dorsal PFC during chewing while wearing a dental prosthesis, compared with controls without dentures, although experimental studies in animal models suggested that other cerebral zones are activated during mastication, not only the PFC. Furthermore, according to the study by Kamiya et al ., 12 prefrontal activation is not related to age, because little difference was found between elderly participants wearing dentures during mastication and young healthy controls.…”

“…Furthermore, according to the study by Kamiya et al ., 12 prefrontal activation is not related to age, because little difference was found between elderly participants wearing dentures during mastication and young healthy controls. Thus, it has been suggested that a compensatory mechanism allows the response to increasing masticatory cognitive demand, activating the same prefrontal region. Nevertheless, with the available evidence, it is estimated that early dental rehabilitation can contribute not only to chewing comfort and oral quality of life in aged people, but also with the prevention of cognitive deficiencies in adults.…”

Prefrontal modulation during chewing performance in occlusal dysesthesia patients: a functional near-infrared spectroscopy study

“…On the other hand, OD patients did not demonstrate any significant modifications of occlusal state or chewing activities as compared to HC subjects. It has been previously reported that prefrontal activity during chewing is involved in food preference [29], selfevaluation of chewing ability [35,40], food reward [35], food representation, and monitoring of eating behavior [52]. Furthermore, the DLPFC and m-PFC are also involved in multisensory sensory functioning as well as execution, attention, and working memory participations [25][26][27][28][29]32].…”

“…Several studies have been conducted to define prefrontal cognitive functioning in regard to food flavor [33], food hardness [34], and sensorimotor generation [35] during chewing. In the present study, we investigated specific behaviors that might be modulated by occlusal contact conditions in OD patients.…”