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Wang X, Pang Q, Hu J, Luo B, Lu Y, Sun X, Meng S, Jiang Q. Cognitive decline in Sprague-Dawley rats induced by neuroplasticity changes after occlusal support loss. CNS Neurosci Ther 2024; 30:e14750. [PMID: 38898731 PMCID: PMC11187409 DOI: 10.1111/cns.14750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 02/28/2024] [Accepted: 04/20/2024] [Indexed: 06/21/2024] Open
Abstract
BACKGROUND Tooth loss is closely related to cognitive impairment, especially affecting cognitive functions involving hippocampus. The most well-known function of the hippocampus is learning and memory, and the mechanism behind is neuroplasticity, which strongly depends on the level of brain-derived neurotrophic factor (BDNF). While research has delved into the possible mechanisms behind the loss of teeth leading to cognitive dysfunction, there are few studies on the plasticity of sensory neural pathway after tooth loss, and the changes in related indicators of synaptic plasticity still need to be further explored. METHODS In this study, the bilateral maxillary molars were extracted in Sprague-Dawley rats of two age ranges (young and middle age) to establish occlusal support loss model; then, the spatial cognition was tested by Morris Water Maze (MWM). Quantitative real-time PCR (qPCR) and Western Blotting (WB) were used to detect BDNF, AKT, and functional proteins (viz., PSD95 and NMDAR) of hippocampal synapses. Golgi staining was used to observe changes in ascending nerve pathway. IF was used to confirm the location of BDNF and AKT expressed in hippocampus. RESULTS MWM showed that the spatial cognitive level of rats dropped after occlusal support loss. qPCR, WB, and IF suggested that the BDNF/AKT pathway was down-regulated in the hippocampus. Golgi staining showed the neurons of ascending sensory pathway decreased in numbers. CONCLUSION Occlusal support loss caused plastic changes in ascending nerve pathway and induced cognitive impairment in rats by down-regulating BDNF and synaptic plasticity.
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Affiliation(s)
- Xiaoyu Wang
- School of StomatologyCapital Medical UniversityBeijingChina
| | - Qian Pang
- Department of Prosthodontics, Beijing Stomatological HospitalCapital Medical UniversityBeijingChina
| | - Jiangqi Hu
- Department of Prosthodontics, Beijing Stomatological HospitalCapital Medical UniversityBeijingChina
| | - Bin Luo
- Department of Prosthodontics, Beijing Stomatological HospitalCapital Medical UniversityBeijingChina
| | - Yunping Lu
- Department of Prosthodontics, Beijing Stomatological HospitalCapital Medical UniversityBeijingChina
| | - Xu Sun
- School of StomatologyCapital Medical UniversityBeijingChina
| | - Shixiang Meng
- School of StomatologyCapital Medical UniversityBeijingChina
| | - Qingsong Jiang
- Department of Prosthodontics, Beijing Stomatological HospitalCapital Medical UniversityBeijingChina
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2
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Murray GM, Sessle BJ. Pain-sensorimotor interactions: New perspectives and a new model. NEUROBIOLOGY OF PAIN (CAMBRIDGE, MASS.) 2024; 15:100150. [PMID: 38327725 PMCID: PMC10847382 DOI: 10.1016/j.ynpai.2024.100150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 11/25/2023] [Accepted: 01/19/2024] [Indexed: 02/09/2024]
Abstract
How pain and sensorimotor behavior interact has been the subject of research and debate for many decades. This article reviews theories bearing on pain-sensorimotor interactions and considers their strengths and limitations in the light of findings from experimental and clinical studies of pain-sensorimotor interactions in the spinal and craniofacial sensorimotor systems. A strength of recent theories is that they have incorporated concepts and features missing from earlier theories to account for the role of the sensory-discriminative, motivational-affective, and cognitive-evaluative dimensions of pain in pain-sensorimotor interactions. Findings acquired since the formulation of these recent theories indicate that additional features need to be considered to provide a more comprehensive conceptualization of pain-sensorimotor interactions. These features include biopsychosocial influences that range from biological factors such as genetics and epigenetics to psychological factors and social factors encompassing environmental and cultural influences. Also needing consideration is a mechanistic framework that includes other biological factors reflecting nociceptive processes and glioplastic and neuroplastic changes in sensorimotor and related brain and spinal cord circuits in acute or chronic pain conditions. The literature reviewed and the limitations of previous theories bearing on pain-sensorimotor interactions have led us to provide new perspectives on these interactions, and this has prompted our development of a new concept, the Theory of Pain-Sensorimotor Interactions (TOPSMI) that we suggest gives a more comprehensive framework to consider the interactions and their complexity. This theory states that pain is associated with plastic changes in the central nervous system (CNS) that lead to an activation pattern of motor units that contributes to the individual's adaptive sensorimotor behavior. This activation pattern takes account of the biological, psychological, and social influences on the musculoskeletal tissues involved in sensorimotor behavior and on the plastic changes and the experience of pain in that individual. The pattern is normally optimized in terms of biomechanical advantage and metabolic cost related to the features of the individual's musculoskeletal tissues and aims to minimize pain and any associated sensorimotor changes, and thereby maintain homeostasis. However, adverse biopsychosocial factors and their interactions may result in plastic CNS changes leading to less optimal, even maladaptive, sensorimotor changes producing motor unit activation patterns associated with the development of further pain. This more comprehensive theory points towards customized treatment strategies, in line with the management approaches to pain proposed in the biopsychosocial model of pain.
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Affiliation(s)
- Greg M. Murray
- Discipline of Restorative and Reconstructive Dentistry, Sydney School of Dentistry, Faculty of Medicine and Health, The University of Sydney, Darcy Road, Westmead, NSW 2145, Australia
| | - Barry J. Sessle
- Faculty of Dentistry and Temerty Faculty of Medicine Department of Physiology, and Centre for the Study of Pain, University of Toronto, 124 Edward St, Toronto, ON M5G 1G6, Canada
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3
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Oue H, Hatakeyama R, Ishida E, Yokoi M, Tsuga K. Experimental tooth loss affects spatial learning function and blood-brain barrier of mice. Oral Dis 2023; 29:2907-2916. [PMID: 36114741 DOI: 10.1111/odi.14379] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/28/2022] [Accepted: 09/12/2022] [Indexed: 11/30/2022]
Abstract
OBJECTIVE This study aims to investigate how experimental tooth loss affected learning, memory function, and brain pathophysiology in mice. MATERIALS AND METHODS The mice (C57BL/6 J, 2-month-old, male) were divided into tooth loss and control groups. The behavioral test battery was performed at 6 and 12 months after tooth extraction. The protein levels of the tight junctions in the brains of the mice were analyzed. Hippocampal astrocyte was measured using immunohistochemical staining. RESULTS The results of behavioral tests and biochemical analysis performed during the 6 months observation period did not show significant differences between the groups. However, the escape latency in the tooth loss group was significantly longer than that in the control group at the 12 months after tooth extraction. The level of claudin-5 decreased in the tooth loss group. Additionally, hippocampal astrogliosis was found in the tooth loss group. CONCLUSIONS Experimental tooth loss reduced the level of claudin-5 and caused astrogliosis in the brains of mice, which was accompanied by deterioration of learning functions. This study may provide a new insight about the association between tooth loss and cognitive dysfunction.
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Affiliation(s)
- Hiroshi Oue
- Department of Advanced Prosthodontics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Rie Hatakeyama
- Department of Advanced Prosthodontics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Eri Ishida
- Department of Advanced Prosthodontics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Miyuki Yokoi
- Department of Advanced Prosthodontics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Kazuhiro Tsuga
- Department of Advanced Prosthodontics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
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Skallevold HE, Rokaya N, Wongsirichat N, Rokaya D. Importance of oral health in mental health disorders: An updated review. J Oral Biol Craniofac Res 2023; 13:544-552. [PMID: 37396968 PMCID: PMC10314291 DOI: 10.1016/j.jobcr.2023.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 06/05/2023] [Accepted: 06/14/2023] [Indexed: 07/04/2023] Open
Abstract
Background Mental disorders are indeed an expanding threat, which requires raised awareness, education, prevention, and treatment initiatives nationally and globally. This review presents an updated review on the relationships between oral health and mental health disorders and the importance of oral health in mental health disorders. Method A literature search was done regarding mental disorders and oral health approaches in Google Scholar and PubMed from the year 1995 until 2023. All the English-language papers were evaluated based on the inclusion criteria. Publications included original research papers, review articles and book chapters. Results Common mental disorders include depression, anxiety, bipolar disorder, Schizophrenia, dementia, and alcohol and drug use disorders. The interplay of oral health and mental disorders involves dysregulated microbiome, translocated bacteria, and systemic inflammation, among others. Conclusion There is a complex relationship between mental disorders and oral diseases. Various oral health problems are associated with mental health problems. The interplay of oral health and mental disorders involves dysregulated microbiome, translocated bacteria, and systemic inflammation, among others. Mental health nurses including physicians and dental professionals should be involved in the oral health care of mental health disorder patients. Therefore, multidisciplinary should be involved in the care of mental health disorders, and they should consider oral health care as an essential part of their care for patients with mental health disorders. Future investigations should strive to elucidate the exact biological relationships, to develop new directions for treatment.
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Affiliation(s)
- Hans Erling Skallevold
- Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Chulalongkorn University, Bangkok, 10330, Thailand
| | | | - Natthamet Wongsirichat
- Faculty of Dentistry, Bangkok Thonburi University, 16/10 Taweewatana, Bangkok, 10170, Thailand
| | - Dinesh Rokaya
- Department of Clinical Dentistry, Walailak University International College of Dentistry, Bangkok, 10400, Thailand
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Winning L, De Looze C, Knight SP, Carey D, Meaney JF, Kenny RA, O'Connell B. Tooth loss and regional grey matter volume. J Dent 2023; 129:104393. [PMID: 36563839 DOI: 10.1016/j.jdent.2022.104393] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 12/13/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022] Open
Abstract
OBJECTIVES To investigate whether tooth loss was associated with regional grey matter volume (GMV) in a group of community dwelling older men and women from Ireland. METHODS A group of 380 dementia-free men and women underwent a dental examination and had a Magnetic Resonance Imaging (MRI) scan as part of The Irish Longitudinal Study of Aging (TILDA). Cortical parcellation was conducted using Freesurfer utilities to produce volumetric measures of gyral based regions of interest. Analysis included multiple linear regression to investigate the association between tooth loss and regional GMVs with adjustment for various confounders. RESULTS The mean age of participants was 68.1 years (SD 7.3) and 51.6% of the group were female. 50 (13.2%) of the participants were edentulous, 148 (38.9%) had 1-19 teeth, and 182 (47.9%) had ≥20 teeth. Multiple liner regression analysis with adjustment for a range of potential confounders showed associations between the number of teeth and GMVs in the paracentral lobule and the cuneus cortex. In the paracentral lobule, comparing participants with 1-19 teeth versus edentates there was an increase in GMV of β=323.0mm3 (95% Confidence Interval [CI] 84.5, 561.6) and when comparing participants with ≥20 teeth to edentates there was an increase of β=382.3mm3 (95% CI 126.9, 637.7). In the cuneus cortex, comparing participants with ≥20 teeth to edentates there was an increase in GMV of β=380.5mm3 (95% CI 69.4, 691.5). CONCLUSIONS In this group of older men and women from Ireland, the number of teeth was associated with GMVs in the paracentral lobule and the cuneus cortex independent of various known confounders. CLINICAL SIGNIFICANCE Although not proof of causation, the finding that tooth loss was associated with regional reduced GMV in the brain may represent a potential explanatory link to the observed association between tooth loss and cognitive decline.
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Affiliation(s)
- Lewis Winning
- Dublin Dental University Hospital, Trinity College Dublin, Ireland.
| | - Céline De Looze
- The Irish Longitudinal Study on Ageing (TILDA), Trinity College Dublin, Ireland
| | - Silvin P Knight
- The Irish Longitudinal Study on Ageing (TILDA), Trinity College Dublin, Ireland
| | - Daniel Carey
- The Irish Longitudinal Study on Ageing (TILDA), Trinity College Dublin, Ireland; School of Medicine, Trinity College Dublin, Ireland
| | - James F Meaney
- School of Medicine, Trinity College Dublin, Ireland; The National Centre for Advanced Medical Imaging (CAMI), St. James's Hospital, Dublin, Ireland
| | - Rose Anne Kenny
- The Irish Longitudinal Study on Ageing (TILDA), Trinity College Dublin, Ireland; Mercer's Institute for Successful Ageing, St James's Hospital, Dublin, Ireland
| | - Brian O'Connell
- Dublin Dental University Hospital, Trinity College Dublin, Ireland; The Irish Longitudinal Study on Ageing (TILDA), Trinity College Dublin, Ireland
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6
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Matsuyama Y, Fujiwara T, Murayama H, Machida M, Inoue S, Shobugawa Y. Differences in Brain Volume by Tooth Loss and Cognitive Function in Older Japanese Adults. Am J Geriatr Psychiatry 2022; 30:1271-1279. [PMID: 35831211 DOI: 10.1016/j.jagp.2022.06.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 06/07/2022] [Accepted: 06/10/2022] [Indexed: 01/25/2023]
Abstract
BACKGROUND We investigated the association between tooth loss and structural brain volume and its mediating effect on the association between tooth loss and cognitive function in older Japanese. METHODS A cross-sectional study was conducted by using the data of 494 randomly sampled community-dwelling individuals aged 65-84 years living in Tokamachi City, Japan. Total brain volume (TBV), gray matter volume (GMV), white matter volume (WMV), and hippocampal volume (HV) were measured with magnetic resonance imaging. The association of self-reported number of teeth (≥20, 1-19, and 0) with cognitive function assessed with the Japanese version of the Quick Mild Cognitive Impairment screen and structural brain volume was examined. Causal mediation analysis was performed to evaluate the mediating effect of structural brain volume. Age, sex, socioeconomic status, health behavior, comorbid conditions, and total intracranial volume were adjusted. RESULTS Respondents with no teeth showed lower cognitive function (coefficient = -4.01; 95% confidence interval [CI]: -7.19, -0.82), lower TBV (coefficient = -10.34; 95% CI: -22.84, 2.17), and lower GMV (coefficient = -6.92; 95% CI: -14.84, 0.99) than those with ≥20 teeth (P for trends were 0.003, 0.035, and 0.047, respectively). The number of teeth was not significantly associated with WMV or HV. GMV showed a significant mediating effect on the association between the number of teeth and cognitive function (coefficient = -0.38; 95% CI: -1.14, -0.002, corresponding to 9.0% of the total effect), whereas TBV did not. CONCLUSIONS GMV was suggested to mediate the relationship between tooth loss and lower cognitive function.
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Affiliation(s)
- Yusuke Matsuyama
- Department of Global Health Promotion, Tokyo Medical and Dental University (YM, TF), Tokyo, Japan.
| | - Takeo Fujiwara
- Department of Global Health Promotion, Tokyo Medical and Dental University (YM, TF), Tokyo, Japan
| | - Hiroshi Murayama
- Research Team for Social participation and Community Health, Tokyo Metropolitan Institute of Gerontology (HM), Tokyo, Japan
| | - Masaki Machida
- Department of Preventive Medicine and Public Health, Tokyo Medical University (MM, SI), Tokyo, Japan; Department of Infection Prevention and Control, Tokyo Medical University Hospital (MM), Tokyo, Japan
| | - Shigeru Inoue
- Department of Preventive Medicine and Public Health, Tokyo Medical University (MM, SI), Tokyo, Japan
| | - Yugo Shobugawa
- Department of Active Ageing (donated by Tokamachi city, Niigata Japan), Niigata University Graduate School of Medical and Dental Sciences (YS), Niigata, Japan
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7
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Chronic Orofacial Pain: Models, Mechanisms, and Genetic and Related Environmental Influences. Int J Mol Sci 2021; 22:ijms22137112. [PMID: 34281164 PMCID: PMC8268972 DOI: 10.3390/ijms22137112] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 12/13/2022] Open
Abstract
Chronic orofacial pain conditions can be particularly difficult to diagnose and treat because of their complexity and limited understanding of the mechanisms underlying their aetiology and pathogenesis. Furthermore, there is considerable variability between individuals in their susceptibility to risk factors predisposing them to the development and maintenance of chronic pain as well as in their expression of chronic pain features such as allodynia, hyperalgesia and extraterritorial sensory spread. The variability suggests that genetic as well as environmental factors may contribute to the development and maintenance of chronic orofacial pain. This article reviews these features of chronic orofacial pain, and outlines findings from studies in animal models of the behavioural characteristics and underlying mechanisms related to the development and maintenance of chronic orofacial pain and trigeminal neuropathic pain in particular. The review also considers the role of environmental and especially genetic factors in these models, focussing on findings of differences between animal strains in the features and underlying mechanisms of chronic pain. These findings are not only relevant to understanding underlying mechanisms and the variability between patients in the development, expression and maintenance of chronic orofacial pain, but also underscore the importance for considering the strain of the animal to model and explore chronic orofacial pain processes.
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Patel S, Howard D, Chowdhury N, Derieux C, Wellslager B, Yilmaz Ö, French L. Characterization of Human Genes Modulated by Porphyromonas gingivalis Highlights the Ribosome, Hypothalamus, and Cholinergic Neurons. Front Immunol 2021; 12:646259. [PMID: 34194426 PMCID: PMC8236716 DOI: 10.3389/fimmu.2021.646259] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Accepted: 05/20/2021] [Indexed: 12/12/2022] Open
Abstract
Porphyromonas gingivalis, a bacterium associated with periodontal disease, is a suspected cause of Alzheimer's disease. This bacterium is reliant on gingipain proteases, which cleave host proteins after arginine and lysine residues. To characterize gingipain susceptibility, we performed enrichment analyses of arginine and lysine proportion proteome-wide. Genes differentially expressed in brain samples with detected P. gingivalis reads were also examined. Genes from these analyses were tested for functional enrichment and specific neuroanatomical expression patterns. Proteins in the SRP-dependent cotranslational protein targeting to membrane pathway were enriched for these residues and previously associated with periodontal and Alzheimer's disease. These ribosomal genes are up-regulated in prefrontal cortex samples with detected P. gingivalis sequences. Other differentially expressed genes have been previously associated with dementia (ITM2B, MAPT, ZNF267, and DHX37). For an anatomical perspective, we characterized the expression of the P. gingivalis associated genes in the mouse and human brain. This analysis highlighted the hypothalamus, cholinergic neurons, and the basal forebrain. Our results suggest markers of neural P. gingivalis infection and link the cholinergic and gingipain hypotheses of Alzheimer's disease.
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Affiliation(s)
- Sejal Patel
- Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Derek Howard
- Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Nityananda Chowdhury
- Department of Oral Health Sciences, Medical University of South Carolina, Charleston, SC, United States
| | - Casey Derieux
- Department of Oral Health Sciences, Medical University of South Carolina, Charleston, SC, United States
| | - Bridgette Wellslager
- Department of Oral Health Sciences, Medical University of South Carolina, Charleston, SC, United States
| | - Özlem Yilmaz
- Department of Oral Health Sciences, Medical University of South Carolina, Charleston, SC, United States
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, United States
| | - Leon French
- Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
- Institute for Medical Science, University of Toronto, Toronto, ON, Canada
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Lin CS, Lin HH, Fann SW, Lee WJ, Hsu ML, Wang SJ, Fuh JL. Association between tooth loss and gray matter volume in cognitive impairment. Brain Imaging Behav 2021; 14:396-407. [PMID: 32170642 DOI: 10.1007/s11682-020-00267-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Previous studies have reported an association between tooth loss and gray matter volume (GMV) in healthy adults. The study aims to elucidate the link between tooth loss, brain volume differences, and cognitive impairment by investigating the total and regional differences in GMV associated with tooth loss in older people with and without cognitive impairment. Forty older participants with mild cognitive impairment or Alzheimer's disease [the cognitive impairment (CI) group] and 30 age- and sex-matched healthy participants [the control (CON) group] received T1-weighted magnetic resonance imaging scans and assessments of oral functions, including masticatory performance (MP) and the number of missing teeth (NMT). Voxel-based morphometry was used to assess the total and regional GMV, including that of the medial temporal lobe and motor-related areas. (A) When the total intracranial volume and age were controlled for, an increased MP was associated with a larger GMV in the premotor cortex in the CON group. (B) In the CI group, an increased NMT was significantly correlated with smaller regional GMV of the bilateral primary motor cortex and the premotor cortex. (C) In the CI group, but not the CON group, an increased NMT was associated with both smaller total GMV and regional GMV of the left medial temporal lobe, including the left hippocampus and parahippocampus. Tooth loss may be preferentially related to the structural differences in the medial temporal lobe in cognitively impaired older people. Further research is required to understand the mechanisms of the relationships.
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Affiliation(s)
- Chia-Shu Lin
- Department of Dentistry, School of Dentistry, National Yang-Ming University, Taipei City, Taiwan.,Institute of Brain Science, National Yang-Ming University, Taipei City, Taiwan.,Brain Research Center, National Yang-Ming University, Taipei City, Taiwan
| | - Hsiao-Han Lin
- Department of Dentistry, School of Dentistry, National Yang-Ming University, Taipei City, Taiwan
| | - Shin-Woei Fann
- Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei City, Taiwan, 122
| | - Wei-Ju Lee
- Neurological Institute, Taichung Veterans General Hospital, Taichung, Taiwan.,Faculty of Medicine, National Yang-Ming University, Taipei City, Taiwan
| | - Ming-Lun Hsu
- Department of Dentistry, School of Dentistry, National Yang-Ming University, Taipei City, Taiwan
| | - Shuu-Jiun Wang
- Brain Research Center, National Yang-Ming University, Taipei City, Taiwan. .,Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei City, Taiwan, 122. .,Faculty of Medicine, National Yang-Ming University, Taipei City, Taiwan.
| | - Jong-Ling Fuh
- Brain Research Center, National Yang-Ming University, Taipei City, Taiwan. .,Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei City, Taiwan, 122. .,Faculty of Medicine, National Yang-Ming University, Taipei City, Taiwan.
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Lopez-Chaichio L, Padial-Molina M, O'Valle F, Gil-Montoya JA, Catena A, Galindo-Moreno P. Oral health and healthy chewing for healthy cognitive ageing: A comprehensive narrative review. Gerodontology 2020; 38:126-135. [PMID: 33179281 DOI: 10.1111/ger.12510] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 09/11/2020] [Accepted: 10/24/2020] [Indexed: 12/18/2022]
Abstract
INTRODUCTION Ageing leads to physiological cognitive decline that it is worsened in people with neurodegenerative diseases such as Alzheimer's disease. Despite the ongoing search for a solution to this cognitive decline, no effective remedies have been established. It has been determined that modifiable external factors, such as oral health and occlusal function, prevent cognitive decline. OBJECTIVE To analyse the primary interactions between occlusal function and cognitive functions. MAIN FINDINGS Masticatory function is related to cognitive functions. In particular, current evidence, from both animal and human studies, suggests that the activation of masticatory muscles and proper mastication, with natural teeth or dental prosthesis, induces the release of several mediators and the activation of specific brain areas. Together, they result in higher neuronal activity, neurotrophic support, blood flow and the prevention of amyloid-beta plaque formation. Thus, all the components of the masticatory system must work together in order to preserve cognitive function. CONCLUSIONS Available evidence suggests that oral and cognitive health are more interconnected than previously thought. Therefore, maintenance and adequate restoration of the whole masticatory system are important for the prevention of cognitive decline. In summary, oral and chewing health lead to healthy cognitive ageing.
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Affiliation(s)
- Lucia Lopez-Chaichio
- Department of Oral Surgery and Implant Dentistry, School of Dentistry, University of Granada, Granada, Spain
| | - Miguel Padial-Molina
- Department of Oral Surgery and Implant Dentistry, School of Dentistry, University of Granada, Granada, Spain
| | - Francisco O'Valle
- Department of Pathology and IBIMER, School of Medicine, University of Granada, Granada, Spain.,Biosanitary Institute of Granada (ibs.Granada), University of Granada, Granada, Spain
| | - Jose Antonio Gil-Montoya
- Biosanitary Institute of Granada (ibs.Granada), University of Granada, Granada, Spain.,Department of Gerodontology, School of Dentistry, University of Granada, Granada, Spain
| | - Andres Catena
- Mind, Brain and Behavior Research Center, University of Granada, Granada, Spain
| | - Pablo Galindo-Moreno
- Department of Oral Surgery and Implant Dentistry, School of Dentistry, University of Granada, Granada, Spain
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11
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Tan D, Foster S, Korgaonkar MS, Oxenham V, Whittle T, Klineberg I. The role of progressive oral implant rehabilitation in mastication, cognition and oral health‐related quality of life outcomes—A pilot to define the protocol. J Oral Rehabil 2020; 47:1368-1381. [DOI: 10.1111/joor.13085] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/10/2020] [Indexed: 12/23/2022]
Affiliation(s)
- Daniel Tan
- Department of Oral Rehabilitation School of Dentistry Faculty of Medicine and Health University of Sydney Sydney Australia
| | - Sheryl Foster
- School of Health Sciences Faculty of Medicine and Health University of Sydney Sydney Australia
- Radiology Department Westmead Hospital Sydney Australia
| | - Mayuresh S. Korgaonkar
- School of Health Sciences Faculty of Medicine and Health University of Sydney Sydney Australia
- Brain Dynamics Centre Westmead Institute for Medical Research, University of Sydney Sydney Australia
| | - Vincent Oxenham
- Department of Psychology Faculty of Medicine, Health and Human Sciences Macquarie University Sydney Australia
| | - Terry Whittle
- Department of Oral Rehabilitation School of Dentistry Faculty of Medicine and Health University of Sydney Sydney Australia
| | - Iven Klineberg
- Department of Oral Rehabilitation School of Dentistry Faculty of Medicine and Health University of Sydney Sydney Australia
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12
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Lin CS. Functional Adaptation of Oromotor Functions and Aging: A Focused Review of the Evidence From Brain Neuroimaging Research. Front Aging Neurosci 2020; 11:354. [PMID: 31998112 PMCID: PMC6962247 DOI: 10.3389/fnagi.2019.00354] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 12/05/2019] [Indexed: 12/11/2022] Open
Abstract
“Practice makes perfect” is a principle widely applied when one is acquiring a new sensorimotor skill to cope with challenges from a new environment. In terms of oral healthcare, the traditional view holds that restoring decayed structures is one of the primary aims of treatment. This assumes that the patient’s oromotor functions would be recovered back to normal levels after the restoration. However, in older patients, such a structural–functional coupling after dental treatment shows a great degree of individual variations. For example, after prosthodontic treatment, some patients would adapt themselves quickly to the new dentures, while others would not. In this Focused Review, I argue that the functional aspects of adaptation—which would be predominantly associated with the brain mechanisms of cognitive processing and motor learning—play a critical role in the individual differences in the adaptive behaviors of oromotor functions. This thesis is critical to geriatric oral healthcare since the variation in the capacity of cognitive processing and motor learning is critically associated with aging. In this review, (a) the association between aging and the brain-stomatognathic axis will be introduced; (b) the brain mechanisms underlying the association between aging, compensatory behavior, and motor learning will be briefly summarized; (c) the neuroimaging evidence that suggests the role of cognitive processing and motor learning in oromotor functions will be summarized, and critically, the brain mechanisms underlying mastication and swallowing in older people will be discussed; and (d) based on the current knowledge, an experimental framework for investigating the association between aging and the functional adaptation of oromotor functions will be proposed. Finally, I will comment on the practical implications of this framework and postulate questions open for future research.
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Affiliation(s)
- Chia-Shu Lin
- Department of Dentistry, School of Dentistry, National Yang-Ming University, Taipei, Taiwan.,Institute of Brain Science, School of Medicine, National Yang-Ming University, Taipei, Taiwan.,Brain Research Center, National Yang-Ming University, Taipei, Taiwan
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Mostafa S, Hakam HM, El-Motayam A. Gustatory dysfunction in relation to circumvallate papilla's taste buds structure upon unilateral maxillary molar extraction in Wistar rats: an in vivo study. F1000Res 2019; 8:1667. [PMID: 32089825 PMCID: PMC6947764 DOI: 10.12688/f1000research.19684.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/11/2019] [Indexed: 11/24/2022] Open
Abstract
Background: The interaction between taste sensation and dentoalveolar innervation is still under research. teeth loss can alter taste thresholds in humans, but the underlying mechanisms are still obscure. This study investigated the effect of unilateral maxillary molars extraction on the structure of circumvallate papilla in rats. Methods: Thirty-two male Wister rats, aged 3-4 months were randomly distributed into four groups (one control and 3 experimental ) each including 8 animals. The rats were euthanized 3, 6 or 9 weeks following the procedure. The changes in trough length and the taste buds structure and number of both sides of CVP were investigated using routine histological examination followed by statistical analysis. Results: the trough toward the extraction side was obviously shorter with a noticeable decrease of taste buds’ number than the non-extraction side. Taste buds were reduced in size and most of them showed signs of degeneration which was more evident in group II followed by group III, less deformity detected in group IV in comparison to the preceding 2 experimental groups. the non-extraction side of all experimental groups showed normal trough length and generally normal histology of taste buds.
Conclusions: Maxillary molars extraction has a degenerative effect on the structure of taste buds and gustatory epithelium which were more marked at the extraction side and showed improvement upon elongation of follow up period
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Affiliation(s)
- Sana Mostafa
- Department of Oral Biology, Faculty of Dentistry, Cairo University, Cairo, Egypt
| | - Heba M Hakam
- Department of Oral Biology, Faculty of Dentistry, Cairo University, Cairo, Egypt
| | - Amal El-Motayam
- Department of Oral Biology, Faculty of Dentistry, Cairo University, Cairo, Egypt
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Filippini HF, Scalzilli PA, Costa KM, Freitas RDS, Campos MM. Activation of trigeminal ganglion satellite glial cells in CFA-induced tooth pulp pain in rats. PLoS One 2018; 13:e0207411. [PMID: 30419075 PMCID: PMC6231674 DOI: 10.1371/journal.pone.0207411] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 10/30/2018] [Indexed: 02/07/2023] Open
Abstract
This study further investigated the mechanisms underlying the rat model of tooth pulp inflammatory pain elicited by complete Freund's adjuvant (CFA), in comparison to other pulpitis models. Pulps of the left maxillary first molars were accessed. In the CFA group, the pulps were exposed, and CFA application was followed by dental sealing. In the open group, the pulps were left exposed to the oral cavity. For the closed group, the pulps were exposed, and the teeth were immediately sealed. Naïve rats were used as negative controls. Several parameters were evaluated at 1, 2, 3 and 8 days. There was no statistical significant difference among the groups when body weight variation, food or water consumption were compared. Analysis of serum cytokines (IL-1β, TNF or IL-6) or differential blood cell counts did not reveal any evidence of systemic inflammation. The CFA group displayed a significant reduction in the locomotor activity (at 1 and 3 days), associated with an increased activation of satellite glial cells in the ipsilateral trigeminal ganglion (TG; for up to 8 days). Amygdala astrocyte activation was unaffected in any experimental groups. We provide novel evidence indicating that CFA-induced pulp inflammation impaired the locomotor activity, with persistent activation of ipsilateral TG satellite cells surrounding sensory neurons, without any evidence of systemic inflammation or amygdala astrogliosis.
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Affiliation(s)
- Helena F. Filippini
- Programa de Pós-graduação em Odontologia, Escola de Ciências da Saúde, PUCRS, Porto Alegre, RS, Brasil
| | - Paulo A. Scalzilli
- Laboratório de Patologia, Escola de Ciência da Saúde, PUCRS, Porto Alegre, RS, Brasil
- Centro de Pesquisa em Toxicologia e Farmacologia, Escola de Ciências da Saúde, PUCRS, Porto Alegre, RS, Brasil
| | - Kesiane M. Costa
- Programa de Pós-graduação em Medicina e Ciências da Saúde, Escola de Medicina, PUCRS, Porto Alegre, RS, Brasil
| | - Raquel D. S. Freitas
- Centro de Pesquisa em Toxicologia e Farmacologia, Escola de Ciências da Saúde, PUCRS, Porto Alegre, RS, Brasil
- Programa de Pós-graduação em Medicina e Ciências da Saúde, Escola de Medicina, PUCRS, Porto Alegre, RS, Brasil
| | - Maria M. Campos
- Programa de Pós-graduação em Odontologia, Escola de Ciências da Saúde, PUCRS, Porto Alegre, RS, Brasil
- Laboratório de Patologia, Escola de Ciência da Saúde, PUCRS, Porto Alegre, RS, Brasil
- Centro de Pesquisa em Toxicologia e Farmacologia, Escola de Ciências da Saúde, PUCRS, Porto Alegre, RS, Brasil
- Programa de Pós-graduação em Medicina e Ciências da Saúde, Escola de Medicina, PUCRS, Porto Alegre, RS, Brasil
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Leon M, Woo C. Environmental Enrichment and Successful Aging. Front Behav Neurosci 2018; 12:155. [PMID: 30083097 PMCID: PMC6065351 DOI: 10.3389/fnbeh.2018.00155] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 07/04/2018] [Indexed: 12/18/2022] Open
Abstract
The human brain sustains a slow but progressive decline in function as it ages and these changes are particularly profound in cognitive processing. A potential contributor to this deterioration is the gradual decline in the functioning of multiple sensory systems and the effects they have on areas of the brain that mediate cognitive function. In older adults, diminished capacity is typically observed in the visual, auditory, masticatory, olfactory, and motor systems, and these age-related declines are associated with both a decline in cognitive proficiency, and a loss of neurons in regions of the brain. We will review how the loss of hearing, vision, mastication skills, olfactory impairment, and motoric decline accompany cognitive loss, and how improved functioning of these systems may aid in the restoration of the cognitive abilities in older adults. The human brain appears to require a great deal of stimulation to maintain its cognitive efficacy as people age and environmental enrichment may aid in its maintenance and recovery.
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Affiliation(s)
- Michael Leon
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, United States
| | - Cynthia Woo
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, United States
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Tooth loss is associated with accelerated cognitive decline and volumetric brain differences: a population-based study. Neurobiol Aging 2018; 67:23-30. [PMID: 29609079 DOI: 10.1016/j.neurobiolaging.2018.03.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 03/01/2018] [Accepted: 03/01/2018] [Indexed: 01/07/2023]
Abstract
Tooth loss has been related to cognitive impairment; however, its relation to structural brain differences in humans is unknown. Dementia-free participants (n = 2715) of age ≥60 years were followed up for up to 9 years. A subsample (n = 394) underwent magnetic resonance imaging at baseline. Information on tooth loss was collected at baseline, and cognitive function was assessed using the Mini-Mental State Examination at baseline and at follow-ups. Data were analyzed using linear mixed effects models and linear regression models. At baseline, 404 (14.9%) participants had partial tooth loss, and 206 (7.6%) had complete tooth loss. Tooth loss was significantly associated with a steeper cognitive decline (β: -0.18, 95% confidence interval [CI]: -0.24 to -0.11) and remained significant after adjusting for or stratifying by potential confounders. In cross-sectional analyses, persons with complete or partial tooth loss had significantly lower total brain volume (β: -28.89, 95% CI: -49.33 to -8.45) and gray matter volume (β: -22.60, 95% CI: -38.26 to -6.94). Thus, tooth loss may be a risk factor for accelerated cognitive aging.
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Lin CS. Revisiting the link between cognitive decline and masticatory dysfunction. BMC Geriatr 2018; 18:5. [PMID: 29304748 PMCID: PMC5756393 DOI: 10.1186/s12877-017-0693-z] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 12/18/2017] [Indexed: 12/17/2022] Open
Abstract
Age-related decline in cognitive functions and dementia are major challenges in geriatric healthcare. Accumulating evidence from clinical, epidemiological and animal research suggests that tooth loss may be a risk factor for the decline of cognitive functions. This issue highlights the role of the brain-stomatognathic axis in geriatric medicine. Whether input from the stomatognathic apparatus can affect the brain remains an open debate. By revisiting the evidence published in the past five years, we argue that the hypothesis regarding the association between cognitive decline and masticatory dysfunction should be carefully interpreted. Most of the available clinical and epidemiological studies present only cross-sectional data. With respect to the prospective studies, important confounding factors, such as nutritional and physical conditions, were not fully controlled for. Animal research has revealed that hippocampal deficits may play key roles in the observed cognitive decline. However, experimental intervention and outcome assessments may not capture the condition of human subjects. Brain neuroimaging research may be suitable for bridging the gap between clinical and animal research, potentially contributing to (a) the clarification of the brain network associated with mastication, (b) the identification of brain imaging markers for exploring the mechanisms underlying long-term changes in masticatory functions, and (c) the elucidation of interactions between mastication and other cognitive-affective processing systems. Three potential models of the brain-stomatognathic axis and relevant hypotheses are summarized, focusing on the sensory feedback mechanisms, the compensation of motor control, and cerebellar deficits. Finally, we highlight four critical aspects of study and experimental design that should be considered in future research: (a) the refinement of the considered behavioral assessments, (b) the inclusion of baseline changes in mental and physical conditions,
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Affiliation(s)
- Chia-Shu Lin
- Department of Dentistry, School of Dentistry, National Yang-Ming University, No. 155, Sec. 2, Linong Street, Taipei, 11221, Taiwan.
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