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Yuan X, Liu B, Cuevas P, Brunski J, Aellos F, Petersen J, Koehne T, Bröer S, Grüber R, LeBlanc A, Zhang X, Xu Q, Helms J. Linking the Mechanics of Chewing to Biology of the Junctional Epithelium. J Dent Res 2023; 102:1252-1260. [PMID: 37555395 PMCID: PMC10626588 DOI: 10.1177/00220345231185288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2023] Open
Abstract
The capacity of a tissue to continuously alter its phenotype lies at the heart of how an animal is able to quickly adapt to changes in environmental stimuli. Within tissues, differentiated cells are rigid and play a limited role in adapting to new environments; however, differentiated cells are replenished by stem cells that are defined by their phenotypic plasticity. Here we demonstrate that a Wnt-responsive stem cell niche in the junctional epithelium is responsible for the capability of this tissue to quickly adapt to changes in the physical consistency of a diet. Mechanical input from chewing is required to both establish and maintain this niche. Since the junctional epithelium directly attaches to the tooth surface via hemidesmosomes, a soft diet requires minimal mastication, and consequently, lower distortional strains are produced in the tissue. This reduced strain state is accompanied by reduced mitotic activity in both stem cells and their progeny, leading to tissue atrophy. The atrophied junctional epithelium exhibits suboptimal barrier functions, allowing the ingression of bacteria into the underlying connective tissues, which in turn trigger inflammation and mild alveolar bone loss. These data link the mechanics of chewing to the biology of tooth-supporting tissues, revealing how a stem cell niche is responsible for the remarkable adaptability of the junctional epithelium to different diets.
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Affiliation(s)
- X. Yuan
- Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
- Department of Otolaryngology-Head & Neck Surgery, School of Medicine, Indiana University, Indianapolis, IN, USA
| | - B. Liu
- Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - P. Cuevas
- Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - J. Brunski
- Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - F. Aellos
- Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - J. Petersen
- Department of Orthodontics, University of Leipzig Medical Center, Saxony, Germany
| | - T. Koehne
- Department of Orthodontics, University of Leipzig Medical Center, Saxony, Germany
| | - S. Bröer
- Institute of Pharmacology and Toxicology, School of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - R. Grüber
- Department of Oral Biology, University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria
| | - A. LeBlanc
- Centre for Oral, Clinical & Translational Sciences, Faculty of Dentistry, Oral & Craniofacial Sciences, King’s College London, London, UK
| | - X. Zhang
- Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Disease, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Q. Xu
- Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
- The Affiliated Hospital of Qingdao University, College of Stomatology, Qingdao University, Qingdao, China
| | - J.A. Helms
- Department of Surgery, Stanford University School of Medicine, Stanford, CA, USA
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Zhang X, Yuan X, Xu Q, Arioka M, Van Brunt LA, Shi Y, Brunski J, Helms JA. Molecular Basis for Periodontal Ligament Adaptation to In Vivo Loading. J Dent Res 2019; 98:331-338. [PMID: 30612508 DOI: 10.1177/0022034518817305] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
A soft food diet leads to changes in the periodontal ligament (PDL). These changes, which have been recognized for more than a century, are ascribed to alterations in mechanical loading. While these adaptive responses have been well characterized, the molecular, cellular, and mechanical mechanisms underlying the changes have not. Here, we implicate Wnt signaling in the pathoetiology of PDL responses to underloading. We show that Wnt-responsive cells and their progeny in the PDL space exhibit a burst in proliferation in response to mastication. If an animal is fed a soft diet from the time of weaning, then this burst in Wnt-responsive cell proliferation is quelled; as a consequence, both the PDL and the surrounding alveolar bone undergo atrophy. Returning these animals to a hard food diet restores the Wnt signaling in PDL. These data provide, for the first time, a molecular mechanism underlying the adaptive response of the PDL to loading.
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Affiliation(s)
- X Zhang
- 1 State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,2 Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - X Yuan
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Q Xu
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA.,3 The Affiliated Hospital of Qingdao University, College of Stomatology, Qingdao University, Qingdao, China
| | - M Arioka
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA.,4 Department of Clinical Pharmacology, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - L A Van Brunt
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Y Shi
- 5 Los Altos High School, Los Altos, CA, USA
| | - J Brunski
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - J A Helms
- 2 Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, Stanford University, Palo Alto, CA, USA
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Brunski J, Currey J, Helms J, Leucht P, Nanci A, Nicolella D, Wazen R. Mechanobiology at healing bone-implant interfaces: strain distribution and tissue response. J Biomech 2006. [DOI: 10.1016/s0021-9290(06)83725-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Rangert B, Sennerby L, Meredith N, Brunski J. Design, maintenance and biomechanical considerations in implant placement. Dent Update 1997; 24:416-20. [PMID: 9534417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Successful treatment using implants involves careful consideration of fixture placement and prosthesis design if the biomechanical conditions are to be optimized. These parameters may be related to the implant/tissue interface at the individual fixture level, and thence to the relationship between the components of a prosthesis. The influence of the nature and magnitude of occlusal forces can also be significant and should be carefully assessed before placement.
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Affiliation(s)
- B Rangert
- Department of Biomaterials/Handicap Research Institute for Surgical Sciences, Göteborg University, Medicinaregatan, Gothenburg, Sweden
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