Table 4.
Findings from brain neuroimaging studies related to chewing published in the past five years
| Search criteria: 1. Key word combination: (chewing OR masticat* OR “tooth loss” OR “teeth loss”) AND MRI AND brain 2. Language: English 3. Publication date: 2012.10.15–2017.10.15 | ||
|---|---|---|
| Reference | Task | MRI findings |
| Inamochi et al. 2017 [78] | Chewing, before (Day 0) and after (Day 1/Day 7) inserting a palatal plate | Decreased activation in the bilateral face S1/M1, putamen, left ACC, and right medial posterior frontal cortex on Day 1 vs. Day 0. Activation in the right S1/M1 and putamen recovered to Day 0 level by Day 7. |
| Choi et al. 2017 [65] | Gum chewing | Brain activations at the entorhinal cortex and the parahippocampal cortex, based on an region-of-interest analysis |
| Lotze et al. 2017 [67] | Rubberdam chewing | Increased activation at bilateral S1, S2, M1, PMC, SMA and CG, anterior CB, INS, OFC, THA and left pallidum |
| Lin et al. 2017 [74] | Resting (task-free) condition | The older subjects presented a different functional network associated with masticatory performance, compared to the younger subjects |
| Lin et al. 2015 [72] | Resting (task-free) condition | Grey matter volume in the motor and frontal regions, and the functional connectivity of the cerebellum, was associated with masticatory performance |
| Viggiano et al. 2015 [71] | After vs. before a mastication exercise (gum chewing) | Increased perfusion at the principal trigeminal nucleus but not in the dorsolateral-midbrain |
| Jiang et al. 2015 [66] | Rhythmic chewing | Increased activation at sensorimotor cortex contralateral to the chewing side of preference (CSP), midbrain and brainstem for left CSP, and CB for right CSP |
| Shoi et al. 2014 [70] | Gum chewing; full arch (with a removable partial denture, RPD) vs. short-dental arch (SDR) | Increased activation at middle FG, S1/M1, SMA, putamen, INS and CB for RPD group; no activation at middle FG in SDR group |
| Luraschi et al. 2013 [68] | Three taska, patients with a complete denture | (Across all three functional tasks) increased activation at bilateral pre (M1) and post (S1) central gyrus |
| Hirano et al. 2013 [81] | Two back-to-back ANT sessions with or without gum chewing | (During chewing) increased activation at anterior CG and left FG for the executive network; motor-related regions for attentional networks |
| Quintero et al. 2013a [69] | Gum chewing | Increased activation at CB, motor cortex, caudate nucleus, CG, and brainstem |
| Quintero et al. 2013b [73] | Gum chewing | Increased FC between bilateral M1 and S1, CB, CG and precuneus; increased FC between CB and contralateral CB, bilateral sensorimotor cortex, left superior temporal gyrus, and left CG |
| Yu et al. 2013 [82] | Stress induced by loud noise; gum-chewing | Anterior INS – dACC FC was increased by noise to a lesser extent during gum-chewing (vs. no gum-chewing) |
CB the cerebellum, CG the cingulate gyrus, dACC the dorsal anterior cingulate cortex, FC functional connectivity, FG the frontal gyrus, INS the insula, M1 the primary motor cortex, OFC orbitofrontal cortex, PMC the premotor cortex, S1/S2 primary/secondary somatosensory cortex, SMA supplementary motor area, THA thalamus
aThe tasks included lip pursing, jaw tapping and jaw clenching