What do we learn from brain imaging?—A primer for the dentists who want to know more about the association between the brain and human stomatognathic functions

Abstract

The number of neuroimaging studies on the brain and oral sensorimotor functions has increased recently. Behind the dazzling "brain maps," what does the neuroimaging evidence truly tell us? What can dentists learn from it to improve clinical practice?We summarise the pros and cons of applying magnetic resonance imaging (MRI)based neuroimaging to study oral behaviours of the dental patients. This is a narrative review of previous neuroimaging research of oral functions, focusing on MRI-related studies of human subjects. MRI has gained popularity in dental research due to its non-invasive nature, its approachability and its versatility in quantifying a variety of brain signatures. We argue that MRI-based neuroimaging is suitable for investigating the association between the between-individual variations in brain structure (eg grey matter volume)/brain functions (eg brain activation) and oral behaviours of the patients. Two specific topics of the daily dental practice, mastication and dental fear and anxiety, are discussed to exemplify the potential of neuroimaging methods. The methodological and interpretive limitations of MRI techniques are highlighted, and most importantly, we emphasise that the neuroimaging findings should be carefully interpreted given these limitations. MRI-based neuroimaging techniques can provide a better evaluation of the association between the brain and stomatognathic functions, which could be pivotal to the evidence-based clinical management of dental patients. K E Y W O R D Sbrain, magnetic resonance imaging, neuroimaging, oral medicine, stomatognathic system

Chewing function and related parameters as a function of the degree of dementia: Is there a link between the brain and the mouth?

“…The concept of the ‘brain‐stomatognathic axis’ assumes that both the stomatognathic system and the brain/cognitive conditions contribute collaboratively to oral sensorimotor function. 27 , 65 On the one hand, a top‐down control from the brain to the stomatognathic system (eg control of coordination of motions) has been established. A causal relationship between a decrease in cognition and a chewing dysfunction 66 has been demonstrated in animal research.…”

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

“…382 Twenty-two individuals with OSA (AHI 22 events/h) who were incomplete/nonresponders (residual AHI>5/h) on an initial split-night PSG with a novel MAD containing an oral airway completed an additional split-night PSG with MAD+oral EPAP valve and MAD+oral and nasal EPAP valves (in randomized order). Compared with MAD alone, MAD+oral EPAP significantly reduced the median total AHI, with further reductions with the MAD+oral/nasal EPAP combination (15 versus 10 [7-21] versus 7 [3][4][5][6][7][8][9][10][11][12][13] events/h, P<.01). OSA resolved (AHI<5/h) with MAD+oral/nasal EPAP in 9 participants and 13 had 50% reduction in AHI from baseline.…”

“…Associations between sleep characteristics (8 exposures) and measures of glucose metabolism (3 outcomes) were determined by using multivariate linear regression. Mean (SD) age of the participants was 63 (11) years; 581 (74%) were women; 198 (25%) had DM; and 158 (20%) were taking antihyperglycemic medication. After multivariate adjustment, including antihyperglycemic medication use, the betas (95% CI) for fasting glucose and A1c, respectively, for each SD higher level were 0.13 (0.02, 0.24) mmol/L and 1.11 (0.42, 1.79) mmol/mol for REI associated with 4% oxygen desaturation and 0.16 (0.05, 0.27) mmol/L and 0.77 (0.10, 1.43) mmol/mol for fragmented sleep indices.…”

“…In addition to articles selected for detailed review, a sizable number of excellent general reviews, systematic reviews, meta-analyses, and helpful clinical descriptive articles were also published addressing issues important to prosthodontics. Although it is impractical to provide detailed analysis on all these publications, they are listed here, by topic area, for the reader's convenience: anatomy and physiology, [9][10][11][12][13][14] bone augmentation, 15 bruxism, 16,17 caries, [18][19][20][21][22][23] conventional complete dentures, 24,25 conventional fixed prosthodontics, [26][27][28][29][30] conventional removable partial dentures, 31,32 COVID-19, 33,34 dental hygiene, [35][36][37] dental microbiology, [38][39][40][41][42][43][44] dental occlusion, 45,46 dental wear, 47 digital dentistry, [48][49][50][51][52][53] emerging technolo...…”

Cognitive changes and neural correlates after oral rehabilitation procedures in older adults: a protocol for an interventional study

“…Current research has emphasized the concept of a "brain-stomatognathic axis" in relation to geriatric healthcare. Accordingly, this axis is the complex communication network between the cortical and subcortical regions of the brain and the stomatognathic/masticatory system [7][8][9]. Oral conditions such as loss of teeth [10,11], chronic inflammatory disease such as periodontitis [12], and chewing difficulties [13] are commonly associated with the risk of neurodegenerative diseases [14][15][16][17][18].…”