1
|
Zhang Z, Cui Z, Zhang J, Zheng H, Zhou Z, Wu Z, Wang Z, Fu B. Remineralizing effects of hydroxypropyl methylcellulose film-loaded amorphous calcium phosphate nanoprecursors on enamel artificial caries lesions. J Mech Behav Biomed Mater 2024; 151:106408. [PMID: 38244421 DOI: 10.1016/j.jmbbm.2024.106408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 01/12/2024] [Accepted: 01/15/2024] [Indexed: 01/22/2024]
Abstract
OBJECTIVES This study was to investigate hydroxypropyl methylcellulose (HPMC) film as a carrier for amorphous fluorinated calcium phosphate (AFCP) nanoprecursors to continuously deliver biomimetic remineralization of enamel artificial caries lesions (ACL). MATERIALS AND METHODS The AFCP/HPMC films were comprised of 25 wt% AFCP nanoparticles and 75 wt% HPMC. They were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and biocompatibility tests. Forty enamel ACL were prepared and randomly divided into four groups (n = 10): The enamel surfaces were covered with a pure HPMC film, Tooth Mousse Plus (contains 10% CPP-ACP and 0.2% NaF), and AFCP/HPMC film, or without any things (serving as negative control). Subsequently, all samples were alternatively kept in artificial saliva and a modified pH-cycling before they were characterized by Micro-CT, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), attenuated total reflectance (ATR)-FTIR, XRD, and nanoindentation. RESULTS After the enamel ACL was challenged by pH cycling, Tooth Mousse Plus and AFCP/HPMC film groups exhibited less lesion depth and mineral loss than the negative control and pure HPMC film groups. Additionally, the AFCP/HPMC film group revealed a highest remineralization rate of 55.34 ± 3.10 % among the all groups (p < 0.001). The SEM findings showed that the enamel ACL were densely deposited with minerals in the AFCP/HPMC film group, and the EDX results suggested a higher content of fluorine in the remineralized tissues. In particular, the AFCP/HPMC film group exhibited the best nanomechanical performance after 2 weeks of pH cycling (p < 0.05), with the hardness (H) restored from 0.29 ± 0.19 to 2.69 ± 0.70 GPa, and elastic modulus (Er) restored from 10.77 ± 5.30 to 68.83 ± 12.72 GPa. CONCLUSION The AFCP/HPMC film might be used as a promising strategy for arresting or reversing incipient enamel caries lesions.
Collapse
Affiliation(s)
- Zhixin Zhang
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Zhejiang Provincial Clinical Research Center for Oral Diseases, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Engineering Research Center of Oral Biomaterials and Devices of Zhejiang Province, Hangzhou, 310000, China; Department of Stomatology, Quanzhou First Hospital Affiliated to Fujian Medical University, Quanzhou, 362000, Fujian, China.
| | - Zihan Cui
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Zhejiang Provincial Clinical Research Center for Oral Diseases, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Engineering Research Center of Oral Biomaterials and Devices of Zhejiang Province, Hangzhou, 310000, China
| | - Jianping Zhang
- Department of Orthopaedics, The 909th Hospital, School of Medicine, Xiamen University, Zhangzhou, 363000, Fujian, China
| | - Haiyan Zheng
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Zhejiang Provincial Clinical Research Center for Oral Diseases, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Engineering Research Center of Oral Biomaterials and Devices of Zhejiang Province, Hangzhou, 310000, China
| | - Zihuai Zhou
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Zhejiang Provincial Clinical Research Center for Oral Diseases, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Engineering Research Center of Oral Biomaterials and Devices of Zhejiang Province, Hangzhou, 310000, China
| | - Zhifang Wu
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Zhejiang Provincial Clinical Research Center for Oral Diseases, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Engineering Research Center of Oral Biomaterials and Devices of Zhejiang Province, Hangzhou, 310000, China
| | - Zhe Wang
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Zhejiang Provincial Clinical Research Center for Oral Diseases, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Engineering Research Center of Oral Biomaterials and Devices of Zhejiang Province, Hangzhou, 310000, China.
| | - Baiping Fu
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Zhejiang Provincial Clinical Research Center for Oral Diseases, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Engineering Research Center of Oral Biomaterials and Devices of Zhejiang Province, Hangzhou, 310000, China.
| |
Collapse
|
2
|
Bi R, Sun Y, Xiang L, Xu Z, Ye X, Tian Y, Lin Y, Yang C, Gao Y. TGF-β1/Smad3 Signaling Is Required to Alleviate Fluoride-Induced Enamel Hypomineralization. Biol Trace Elem Res 2024; 202:569-579. [PMID: 37140770 DOI: 10.1007/s12011-023-03688-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 04/28/2023] [Indexed: 05/05/2023]
Abstract
Excessive fluoride intake during enamel development can affect enamel mineralization, leading to dental fluorosis. However, its potential mechanisms remain largely unexplored. In the present study, we aimed to investigate the impact of fluoride on the expressions of RUNX2 and ALPL during mineralization and the effect of TGF-β1 administration on fluoride treatment. A dental fluorosis model of newborn mice and an ameloblast cell line ALC were both used in the present study. The mice of the NaF group, including the mothers and newborns, were fed with water containing 150 ppm NaF after delivery to induce dental fluorosis. The mandibular incisors and molars showed significant abrasion in the NaF group. Immunostaining, qRT-PCR, and Western blotting analysis indicated that exposure to fluoride markedly down-regulated RUNX2 and ALPL in mouse ameloblasts and ALCs. Besides, fluoride treatment significantly decreased the mineralization level detected by ALP staining. Furthermore, exogenous TGF-β1 up-regulated RUNX2 and ALPL and promoted mineralization, while the addition of SIS3 could block such TGF-β1-induced up-regulation. In TGF-β1 conditional knockout mice, the immunostaining of RUNX2 and ALPL was weaker compared with wild-type mice. Exposure to fluoride inhibited the expressions of TGF-β1 and Smad3. Co-treatment of TGF-β1 and fluoride up-regulated RUNX2 and ALPL compared with the fluoride alone treatment, promoting mineralization. Collectively, our data indicated that TGF-β1/Smad3 signaling pathway was necessary for the regulatory effects of fluoride on RUNX2 and ALPL, and the fluoride-induced suppression of ameloblast mineralization was mitigated by activating TGF-β1/Smad3 signaling pathway.
Collapse
Affiliation(s)
- Ruonan Bi
- Department of Pediatrics and Preventive Dentistry, Binzhou Medical University Hospital, Shandong, 256600, Binzhou, China
| | - Yiqun Sun
- Department of Pediatrics and Preventive Dentistry, Binzhou Medical University Hospital, Shandong, 256600, Binzhou, China
| | - Lili Xiang
- Department of Pediatrics and Preventive Dentistry, Binzhou Medical University Hospital, Shandong, 256600, Binzhou, China
| | - Zhenzhen Xu
- Department of Pediatrics and Preventive Dentistry, Binzhou Medical University Hospital, Shandong, 256600, Binzhou, China
| | - Xiaoyuan Ye
- Department of Pediatrics and Preventive Dentistry, Binzhou Medical University Hospital, Shandong, 256600, Binzhou, China
| | - Yanying Tian
- Department of Pediatrics and Preventive Dentistry, Binzhou Medical University Hospital, Shandong, 256600, Binzhou, China
| | - Yao Lin
- Department of Pediatrics and Preventive Dentistry, Binzhou Medical University Hospital, Shandong, 256600, Binzhou, China
| | - Chunyan Yang
- Institute of Stomatology, Binzhou Medical University, Shandong, 264003, Yantai, China.
| | - Yuguang Gao
- Department of Pediatrics and Preventive Dentistry, Binzhou Medical University Hospital, Shandong, 256600, Binzhou, China.
| |
Collapse
|
3
|
Yang J, Huang T, Zhang J, Bai G, Wang W, Yao J, Chen Z, Tu C. Sulphur dioxide and fluoride co-exposure cause enamel damage by disrupting the Cl -/HCO 3- ion transport. J Trace Elem Med Biol 2023; 77:127131. [PMID: 36630759 DOI: 10.1016/j.jtemb.2023.127131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 11/21/2022] [Accepted: 01/04/2023] [Indexed: 01/07/2023]
Abstract
OBJECTIVE Although there is growing evidence linking the exposure to sulphur dioxide (SO2) and fluoride to human diseases, there is little data on the co-exposure of SO2 and fluoride. Moreover, literature on SO2 and fluoride co-exposure to enamel damage is insufficient. In this work, we concentrate on the concurrent environmental issues of excessive SO2 and fluoride in several coal-consuming regions. METHOD To identify the toxicity of SO2 and fluoride exposure either separately or together, we used both ICR mice and LS8 cells, and factorial design was employed to assess the type of potential combined action. RESULT In this study, co-exposure to SO2 and fluoride exacerbated enamel damage, resulting in more severe enamel defects of incisor and the damage occurred earlier. Cl-/HCO3- exchanger expression is increased by SO2 and fluoride in mouse incisor. Consistent with in vivo results, co-exposure of SO2 and fluoride decreased pHi and increased [Cl-]i level by increasing the expression of the Cl-/HCO3- exchanger in LS8 cells. Furthermore, SO2 and F may increase merlin protein expression, and merlin deficiency causes AE2 expression to decrease in vitro. CONCLUSION Overall, these results indicate that co-exposure to SO2 and fluoride may result in more toxicity both in vitro and in vivo than a single exposure to SO2 and fluoride, suggesting that residents in areas contaminated with SO2 and fluoride may be more likely to suffer enamel damage.
Collapse
Affiliation(s)
- Junlin Yang
- School of Public Health, Guizhou Medical University, Guian New Region, China; The Affiliated Hospital of Guizhou Medical University, Guiyang, China
| | - Tongtong Huang
- School of Public Health, Guizhou Medical University, Guian New Region, China
| | - Jianghui Zhang
- School of Public Health, Guizhou Medical University, Guian New Region, China
| | - Guohui Bai
- Key Laboratory of Oral Disease Research, School of Stomatology, Zunyi Medical University, Zunyi, China
| | - Wentai Wang
- School of Public Health, Guizhou Medical University, Guian New Region, China
| | - Jie Yao
- School of Public Health, Guizhou Medical University, Guian New Region, China
| | - Zheng Chen
- School of Public Health, Guizhou Medical University, Guian New Region, China
| | - Chenglong Tu
- Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guian New Region, China; Toxicity Testing Center of Guizhou Medical University, Guiyang, China.
| |
Collapse
|
4
|
Ngu J, Bronckers ALJJ, Katsura K, Zhang Y, Den Besten PK. Na + and K + transport and maturation stage ameloblast modulation. Front Physiol 2023; 14:1124444. [PMID: 36814472 PMCID: PMC9939811 DOI: 10.3389/fphys.2023.1124444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 01/13/2023] [Indexed: 02/08/2023] Open
Abstract
Introduction: Enamel mineralization requires calcium transport into the extracellular matrix for the synthesis of hydroxyapatite (HA) crystals. Formation of HA releases protons into the matrix, which are then neutralized when ameloblasts modulate from cells with apical invaginations, the so-called ruffle-ended ameloblasts (RE), to smooth-ended ameloblasts (SE). Ameloblast modulation is associated with the translocation of the calcium exchanger Nckx4 to the apical border of RE, to remove Na+ from the enamel matrix in exchange for Ca2+ and K+. As enamel matures, Na+ and K+ in the matrix progressively decrease. However, the transporter to remove K+ from mineralizing enamel has not been identified. Methods: Expression of K+ exchangers and channels in secretory and maturation stage of enamel organs were compared following an RNA-seq analysis. Kcnj15, which encodes the Kir4.2 inwardly rectifying K+ channel, was found to be the most upregulated internalizing K+ transporter in maturation stage of enamel organs. Kir4.2 was immunolocalized in wt, Nckx4-/-, Wdr72-/-, and fluorosed ameloblasts. Regulation of Wdr72 expression by pH was characterized in vitro and in vivo. Results: Kir4.2 immunolocalized to the apical border of wild type (wt) mouse RE and cytosol of SE, a spatial distribution pattern shared by NCKX4. In Nckx4-/- ameloblasts, Kir4.2 also localized to the apical surface of RE and cytosol of SE. However, in fluorosed and Wdr72-/- ameloblasts, in which vesicle trafficking is disrupted, Kir4.2 remained in the cytosol. In vitro, Wdr72 was upregulated in LS8 cells cultured in medium with a pH 6.2, which is the pH of the enamel matrix underlying RE, as compared to pH 7.2 under SE. Conclusion: Taken together these results suggest that Kir4.2 participates in K+ uptake by maturation ameloblasts, and that K+ and Na+ uptake by Kir4.2 and Nckx4, respectively, may be regulated by pH through WDR72-mediated endocytosis and membrane trafficking.
Collapse
Affiliation(s)
- Jake Ngu
- Department of Orofacial Sciences, University of California, San Francisco, San Francisco, CA, United States
| | - Antonius L. J. J. Bronckers
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), MOVE Research Institute, University of Amsterdam and VU University, Amsterdam, Netherlands
| | - Kaitlin Katsura
- Department of Orofacial Sciences, University of California, San Francisco, San Francisco, CA, United States
| | - Yan Zhang
- Department of Orofacial Sciences, University of California, San Francisco, San Francisco, CA, United States
| | - Pamela K. Den Besten
- Department of Orofacial Sciences, University of California, San Francisco, San Francisco, CA, United States
| |
Collapse
|
5
|
Revelo-Mejía IA, Enríquez D, Espinosa D, Peña A, Bolaño I, Moná Y, Peña C, Prado D, Ardila L, López J, Cortes Y, Muñoz J, Muñoz J, Sánchez J, Erazo Y, López L, Mosquera A, Pérez D, Ordoñez Y, Torres JH, Hardisson A, Rubio C, Gutiérrez ÁJ, Paz S. Determination of the Fluoride Content in Water of Aqueducts of Cauca (Colombia) by Ion Exchange Chromatography. Biol Trace Elem Res 2021; 199:4867-4875. [PMID: 33405075 DOI: 10.1007/s12011-020-02569-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 12/27/2020] [Indexed: 11/29/2022]
Abstract
Water for human consumption is the main source of fluoride exposure. The concentration in water should not exceed 1 mg/L of fluoride since, at higher levels; it increases the risk of dental fluorosis, among other adverse effects. The fluoride content of 149 water samples from different aqueducts in Cauca (Colombia) has been determined by ion exchange chromatography with the aim of fluoride risk assessment. The rural area of the Municipality of Santander de Quilichao registered fluoride concentrations between 0.012 and 0.150 mg/L. The urban area of Santander de Quilichao recorded lower fluoride levels than the rural area (0.027-0.068 mg/L). The urban area of the Municipality of Cajibío registered fluoride levels of 0.082-0.186 mg/L. The highest levels of fluoride were found in Timbío (0.121-0.210 mg/L). The fluoride levels recorded in this study are not considered sufficient to trigger dental fluorosis. Likewise, optimal levels are not considered to protect the child population against dental caries. However, a monitoring plan of fluoride concentrations in water should be implemented to assure the quality and safe of the water.
Collapse
Affiliation(s)
| | - Daniela Enríquez
- Dentist Research Group of the Urban Zone, Municipality of Santander de Quilichao, Universidad Antonio Nariño, Popayán, Cauca, Colombia
| | - Deisy Espinosa
- Dentist Research Group of the Urban Zone, Municipality of Santander de Quilichao, Universidad Antonio Nariño, Popayán, Cauca, Colombia
| | - Andrés Peña
- Dentist Research Group of the Urban Zone, Municipality of Santander de Quilichao, Universidad Antonio Nariño, Popayán, Cauca, Colombia
| | - Ingrid Bolaño
- Dentist Research Group of the Rural Zone, Municipality of Santander de Quilichao, Universidad Antonio Nariño, Popayán, Cauca, Colombia
| | - Yobany Moná
- Dentist Research Group of the Rural Zone, Municipality of Santander de Quilichao, Universidad Antonio Nariño, Popayán, Cauca, Colombia
| | - Catherine Peña
- Dentist Research Group of the Rural Zone, Municipality of Santander de Quilichao, Universidad Antonio Nariño, Popayán, Cauca, Colombia
| | - Daniel Prado
- Dentist Research Group of the Rural Zone, Municipality of Santander de Quilichao, Universidad Antonio Nariño, Popayán, Cauca, Colombia
| | - Luisa Ardila
- Dentist Research Group, Vereda Pisojé, Municipality of Popayán, Universidad Antonio Nariño, Popayán, Cauca, Colombia
| | - Jennifer López
- Dentist Research Group, Vereda Pisojé, Municipality of Popayán, Universidad Antonio Nariño, Popayán, Cauca, Colombia
| | - Yoely Cortes
- Dentist Research Group, Municipality of Cajibío, Universidad Antonio Nariño, Popayán, Cauca, Colombia
| | - Jennifer Muñoz
- Dentist Research Group, Municipality of Cajibío, Universidad Antonio Nariño, Popayán, Cauca, Colombia
| | - Julieth Muñoz
- Dentist Research Group, Municipality of Cajibío, Universidad Antonio Nariño, Popayán, Cauca, Colombia
| | - Juan Sánchez
- Dentist Research Group, Municipality of Cajibío, Universidad Antonio Nariño, Popayán, Cauca, Colombia
| | - Yuliana Erazo
- Dentist Research Group, Municipality of Piendamó, Universidad Antonio Nariño, Popayán, Cauca, Colombia
| | - Luis López
- Dentist Research Group, Municipality of Piendamó, Universidad Antonio Nariño, Popayán, Cauca, Colombia
| | - Angie Mosquera
- Dentist Research Group, Municipality of Piendamó, Universidad Antonio Nariño, Popayán, Cauca, Colombia
| | - Daniela Pérez
- Dentist Research Group, Municipality of Piendamó, Universidad Antonio Nariño, Popayán, Cauca, Colombia
| | - Yamid Ordoñez
- Dentist Research Group, Municipality of Timbío, Universidad Antonio Nariño, Popayán, Cauca, Colombia
| | - Jhon H Torres
- Dentist Research Group, Municipality of Timbío, Universidad Antonio Nariño, Popayán, Cauca, Colombia
| | - Arturo Hardisson
- Department of Toxicology, Universidad de La Laguna, La Laguna, Tenerife, Canary Islands, Spain
| | - Carmen Rubio
- Department of Toxicology, Universidad de La Laguna, La Laguna, Tenerife, Canary Islands, Spain
| | - Ángel J Gutiérrez
- Department of Toxicology, Universidad de La Laguna, La Laguna, Tenerife, Canary Islands, Spain
| | - Soraya Paz
- Department of Toxicology, Universidad de La Laguna, La Laguna, Tenerife, Canary Islands, Spain.
| |
Collapse
|
6
|
Costiniti V, Bomfim GH, Mitaishvili E, Son GY, Li Y, Lacruz RS. Calcium Transport in Specialized Dental Epithelia and Its Modulation by Fluoride. Front Endocrinol (Lausanne) 2021; 12:730913. [PMID: 34456880 PMCID: PMC8385142 DOI: 10.3389/fendo.2021.730913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 07/26/2021] [Indexed: 11/25/2022] Open
Abstract
Most cells use calcium (Ca2+) as a second messenger to convey signals that affect a multitude of biological processes. The ability of Ca2+ to bind to proteins to alter their charge and conformation is essential to achieve its signaling role. Cytosolic Ca2+ (cCa2+) concentration is maintained low at ~100 nM so that the impact of elevations in cCa2+ is readily sensed and transduced by cells. However, such elevations in cCa2+ must be transient to prevent detrimental effects. Cells have developed a variety of systems to rapidly clear the excess of cCa2+ including Ca2+ pumps, exchangers and sequestering Ca2+ within intracellular organelles. This Ca2+ signaling toolkit is evolutionarily adapted so that each cell, tissue, and organ can fulfill its biological function optimally. One of the most specialized cells in mammals are the enamel forming cells, the ameloblasts, which also handle large quantities of Ca2+. The end goal of ameloblasts is to synthesize, secrete and mineralize a unique proteinaceous matrix without the benefit of remodeling or repair mechanisms. Ca2+ uptake into ameloblasts is mainly regulated by the store operated Ca2+ entry (SOCE) before it is transported across the polarized ameloblasts to reach the insulated enamel space. Here we review the ameloblasts Ca2+ signaling toolkit and address how the common electronegative non-metal fluoride can alter its function, potentially addressing the biology of dental fluorosis.
Collapse
Affiliation(s)
| | | | | | | | | | - Rodrigo S. Lacruz
- Department Molecular Pathobiology, College of Dentistry, New York University, New York, NY, United States
| |
Collapse
|
7
|
Revelo-Mejía IA, Hardisson A, Rubio C, Gutiérrez ÁJ, Paz S. Dental Fluorosis: the Risk of Misdiagnosis-a Review. Biol Trace Elem Res 2021; 199:1762-1770. [PMID: 32705431 DOI: 10.1007/s12011-020-02296-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 07/19/2020] [Indexed: 11/25/2022]
Abstract
Fluoride has been considered as the single factor most frequently responsible for causing enamel mottling. However, in humans, either endogenous and/or exogenous factors not related to fluoride exposure may also cause enamel mottling. In this sense, various studies in the international literature have reported severe mottling of the teeth that could not be attributed to fluoride exposure. Thus, misdiagnosis of non-fluoride-induced enamel defects may occur frequently. Reports of unexpectedly high population prevalence and individual cases of fluorosis, where such diagnoses are irreconcilable with the identified fluoride history, highlight the necessity for a more precise definition and diagnosis of dental fluorosis. Also, a more discriminating diagnostic procedure is suggested. Particularly, positive identification of environmental fluoride levels to which the communities and individuals are exposed shall be developed before the confirmation of a diagnosis of fluorosis. It is considered that a more critical methodology for the diagnosis of fluorosis will be helpful in the rational use and control of fluorides for dental health, and in the identification of factors that may induce enamel defects.
Collapse
Affiliation(s)
- Inés A Revelo-Mejía
- Faculty of Odontology, Universidad Antonio Nariño, Popayán, Bogotá D.C., Colombia
| | - Arturo Hardisson
- Department of Toxicology, Universidad de La Laguna, La Laguna, Tenerife, Canary Islands, Spain
| | - Carmen Rubio
- Department of Toxicology, Universidad de La Laguna, La Laguna, Tenerife, Canary Islands, Spain
| | - Ángel J Gutiérrez
- Department of Toxicology, Universidad de La Laguna, La Laguna, Tenerife, Canary Islands, Spain
| | - Soraya Paz
- Department of Toxicology, Universidad de La Laguna, La Laguna, Tenerife, Canary Islands, Spain.
| |
Collapse
|
8
|
Ji M, Duan X, Han X, Sun J, Zhang D. Exogenous transforming growth factor-β1 prevents the inflow of fluoride to ameleoblasts through regulation of voltage-gated chloride channels 5 and 7. Exp Ther Med 2021; 21:615. [PMID: 33936272 PMCID: PMC8082615 DOI: 10.3892/etm.2021.10047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 03/15/2021] [Indexed: 02/07/2023] Open
Abstract
Dental fluorosis is a global issue. Although there are multiple causes of dental fluorosis, the precise mechanism remains controversial. Previous studies have demonstrated that extracellular fluoride may promote an accumulation of fluoride ions in ameloblasts, which may induce oxidative and endoplasmic reticulum stresses, leading to dental fluorosis. However, the exact process by which fluoride ions enter cells has not been determined. In the present study, intracellular fluoride concentration was determined using a newly developed specific fluorescent probe called probe 1. Under high extracellular fluoride concentrations, the fluorescence intensity of the ameloblasts increased, however, exogenous transforming growth factor-β1 (TGF-β1) was able to inhibit the increase. Furthermore, changes in the expression of the voltage-gated chloride channels 5 and 7 (ClC5 and ClC-7), which are responsible for the transport of fluoride were investigated. The results indicated that fluoride reduced the expression of endogenous TGF-β1 and increased the expression of ClC-5 and ClC-7. Additionally, exogenous TGF-β1 reduced the expression of ClC-5 and ClC-7. The results of the present study indicate that exogenous TGF-β1 may prevent accumulation of fluoride in ameloblasts through the regulation of ClC-5 and ClC-7 under high extracellular fluoride concentrations.
Collapse
Affiliation(s)
- Mei Ji
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Xuejing Duan
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Xiaohui Han
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Jing Sun
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Dongsheng Zhang
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| |
Collapse
|
9
|
Ohki R, Matsuki-Fukushima M, Fujikawa K, Mayahara M, Matsuyama K, Nakamura M. In the absence of a basal lamina, ameloblasts absorb enamel in a serumless and chemically defined organ culture system. J Oral Biosci 2021; 63:66-73. [PMID: 33493674 DOI: 10.1016/j.job.2020.12.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 12/23/2020] [Accepted: 12/17/2020] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Tooth organ development was examined in a serumless, chemically defined organ culture system to determine whether morphological and functional development was identical to that in in vivo and serum-supplemented organ cultures. METHODS Mouse mandibular first molar tooth organs at 16 days of gestation were cultured for up to 28 days in a Tronwell culture system using a serum-supplemented or serumless, chemically defined medium. After culture, specimens were processed for assessing tooth development using ultrastructural, immunohistochemical, and mRNA expression analyses. RESULTS In serum-supplemented conditions, inner enamel epithelial cells differentiated into secretory-stage ameloblasts, which formed enamel and reached the maturation stage after 14 and 21 days of culture, respectively. Ameloblasts deposited a basal lamina on immature enamel. Conversely, in serumless conditions, ameloblasts formed enamel on mineralized dentin after 21 days. Moreover, maturation-stage ameloblasts did not form basal lamina and directly absorbed mineralized enamel after 28 days of culture. RT-PCR analysis indicated that tooth organs, cultured in serumless conditions for 28 days, had significantly reduced expression levels of ODAM, amelotin, and laminin-322. CONCLUSIONS These results indicate that several differences were detected compared to the development in serum-supplemented conditions, such as delayed enamel and dentin formation and the failure of maturation-stage ameloblasts to form basal laminae. Therefore, our results suggest that some factors might be required for the steady formation of mineralized dentin, enamel, and a basal lamina. Additionally, our results indicate that a basal lamina is necessary for enamel maturation.
Collapse
Affiliation(s)
- Retsu Ohki
- Department of Oral Anatomy and Developmental Biology, Showa University School of Dentistry, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 4142-8555, Japan
| | - M Matsuki-Fukushima
- Department of Oral Anatomy and Developmental Biology, Showa University School of Dentistry, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 4142-8555, Japan
| | - K Fujikawa
- Department of Oral Anatomy and Developmental Biology, Showa University School of Dentistry, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 4142-8555, Japan
| | - Mitsuori Mayahara
- Department of Oral Anatomy and Developmental Biology, Showa University School of Dentistry, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 4142-8555, Japan
| | - Kayo Matsuyama
- Department of Oral Anatomy and Developmental Biology, Showa University School of Dentistry, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 4142-8555, Japan
| | - Masanori Nakamura
- Department of Oral Anatomy and Developmental Biology, Showa University School of Dentistry, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 4142-8555, Japan.
| |
Collapse
|
10
|
Aulestia FJ, Groeling J, Bomfim GHS, Costiniti V, Manikandan V, Chaloemtoem A, Concepcion AR, Li Y, Wagner LE, Idaghdour Y, Yule DI, Lacruz RS. Fluoride exposure alters Ca 2+ signaling and mitochondrial function in enamel cells. Sci Signal 2020; 13:eaay0086. [PMID: 32071168 PMCID: PMC7173621 DOI: 10.1126/scisignal.aay0086] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Fluoride ions are highly reactive, and their incorporation in forming dental enamel at low concentrations promotes mineralization. In contrast, excessive fluoride intake causes dental fluorosis, visually recognizable enamel defects that can increase the risk of caries. To investigate the molecular bases of dental fluorosis, we analyzed the effects of fluoride exposure in enamel cells to assess its impact on Ca2+ signaling. Primary enamel cells and an enamel cell line (LS8) exposed to fluoride showed decreased internal Ca2+ stores and store-operated Ca2+ entry (SOCE). RNA-sequencing analysis revealed changes in gene expression suggestive of endoplasmic reticulum (ER) stress in fluoride-treated LS8 cells. Fluoride exposure did not alter Ca2+ homeostasis or increase the expression of ER stress-associated genes in HEK-293 cells. In enamel cells, fluoride exposure affected the functioning of the ER-localized Ca2+ channel IP3R and the activity of the sarco-endoplasmic reticulum Ca2+-ATPase (SERCA) pump during Ca2+ refilling of the ER. Fluoride negatively affected mitochondrial respiration, elicited mitochondrial membrane depolarization, and disrupted mitochondrial morphology. Together, these data provide a potential mechanism underlying dental fluorosis.
Collapse
Affiliation(s)
- Francisco J Aulestia
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY 10010, USA
| | - Johnny Groeling
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY 10010, USA
| | - Guilherme H S Bomfim
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY 10010, USA
| | - Veronica Costiniti
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY 10010, USA
| | - Vinu Manikandan
- Biology Program, Division of Science and Mathematics, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Ariya Chaloemtoem
- Biology Program, Division of Science and Mathematics, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Axel R Concepcion
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
| | - Yi Li
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY 10010, USA
| | - Larry E Wagner
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14526, USA
| | - Youssef Idaghdour
- Biology Program, Division of Science and Mathematics, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - David I Yule
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14526, USA
| | - Rodrigo S Lacruz
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY 10010, USA.
| |
Collapse
|
11
|
Racz R, Nagy A, Rakonczay Z, Dunavari EK, Gerber G, Varga G. Defense Mechanisms Against Acid Exposure by Dental Enamel Formation, Saliva and Pancreatic Juice Production. Curr Pharm Des 2019; 24:2012-2022. [PMID: 29769002 PMCID: PMC6225347 DOI: 10.2174/1381612824666180515125654] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 04/30/2018] [Accepted: 05/08/2018] [Indexed: 12/16/2022]
Abstract
The pancreas, the salivary glands and the dental enamel producing ameloblasts have marked developmental, structural and functional similarities. One of the most striking similarities is their bicarbonate-rich secretory product, serving acid neutralization. An important difference between them is that while pancreatic juice and saliva are delivered into a lumen where they can be collected and analyzed, ameloblasts produce locally precipitating hydroxyapatite which cannot be easily studied. Interestingly, the ion and protein secretion by the pancreas, the salivary glands, and maturation ameloblasts are all two-step processes, of course with significant differences too. As they all have to defend against acid exposure by producing extremely large quantities of bicarbonate, the failure of this function leads to deteriorating consequences. The aim of the present review is to describe and characterize the defense mechanisms of the pancreas, the salivary glands and enamel-producing ameloblasts against acid exposure and to compare their functional capabilities to do this by producing bicarbonate.
Collapse
Affiliation(s)
- Robert Racz
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
| | - Akos Nagy
- Department of Dentistry, Oral and Maxillofacial Surgery, University of Pecs, Pecs, Hungary
| | - Zoltan Rakonczay
- Department of Pathophysiology, University of Szeged, Szeged, Hungary
| | - Erika Katalin Dunavari
- Department of Dentistry, Oral and Maxillofacial Surgery, University of Pecs, Pecs, Hungary
| | - Gabor Gerber
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Gabor Varga
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
| |
Collapse
|
12
|
Gao X, Luo W, Luo X, Li C, Zhang X, Wang Y. Indigenous microbes induced fluoride release from aquifer sediments. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 252:580-590. [PMID: 31185346 DOI: 10.1016/j.envpol.2019.05.118] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 04/17/2019] [Accepted: 05/14/2019] [Indexed: 06/09/2023]
Abstract
Release of fluoride from Quaternary sediments produces F-contaminated groundwater which threatens the health of millions of people worldwide. Despite the mechanisms of fluoride release from sediments are documented by numerous studies, it remains poorly understood that whether indigenous microbes participate in or not for the formation of F-rich groundwater by releasing fluoride from aquifer sediments. A microcosm-based approach, geochemistry and techniques of microbiology and molecular ecology were conducted together to investigate these mechanisms. Results show that microbes are abundant in high [F] groundwater containing at least 1129 operational taxonomic units (OTUs), and indigenous microbes can have an essential role in the mobilization of fluoride in sediments collected from aquifers in a typical fluorosis area in China. It also shows that for the sediments in this study, fluoride release (ca. 2 mg/L) is coupled with elevated concentrations of Ca (△ = 75 mg/L), Mg (△ = 33 mg/L), Al (△ = 0.2 mg/L) and Mn (△ = 1.4 mg/L). This suggests that the fluoride may source from the dissolution of F-bearing carbonate minerals and/or Al-Mn hydroxides in a local acidic environment. The findings provide additional insights into the biogeochemical circulation of fluoride in natural environment, especially in groundwater system and the development of effective strategies for the management of F-contaminated groundwater worldwide.
Collapse
Affiliation(s)
- Xubo Gao
- State Key Laboratory of Biogeology and Environmental Geology & School of Environmental Studies, China University of Geosciences, Wuhan, 430074, PR China
| | - Wenting Luo
- State Key Laboratory of Biogeology and Environmental Geology & School of Environmental Studies, China University of Geosciences, Wuhan, 430074, PR China
| | - Xuesong Luo
- College of Resources and Environment, Huangzhong Agriculture University, Wuhan, 430070, PR China; State Key Laboratory of Biogeology and Environmental Geology & School of Environmental Studies, China University of Geosciences, Wuhan, 430074, PR China
| | - Chengcheng Li
- State Key Laboratory of Biogeology and Environmental Geology & School of Environmental Studies, China University of Geosciences, Wuhan, 430074, PR China.
| | - Xin Zhang
- State Key Laboratory of Biogeology and Environmental Geology & School of Environmental Studies, China University of Geosciences, Wuhan, 430074, PR China
| | - Yanxin Wang
- State Key Laboratory of Biogeology and Environmental Geology & School of Environmental Studies, China University of Geosciences, Wuhan, 430074, PR China
| |
Collapse
|
13
|
Davenport M, Welles AD, Angelopoulou MV, Gonzalez C, Okunseri C, Barbeau L, Bansal NK, Vergotine RJ, Hodgson BD. Prevalence of molar-incisor hypomineralization in Milwaukee, Wisconsin, USA: a pilot study. Clin Cosmet Investig Dent 2019; 11:109-117. [PMID: 31239785 PMCID: PMC6554526 DOI: 10.2147/ccide.s172736] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Accepted: 03/06/2019] [Indexed: 11/23/2022] Open
Abstract
Purpose: This pilot study investigated the prevalence of Molar-Incisor Hypomineralization (MIH) in third-grade school children in Milwaukee Wisconsin, USA. Methods: A convenience sample of third-grade school children in the Milwaukee Public School System (MPS) participated in the study. Calibrated examiners trained on the European Academy of Paediatric Dentistry (EAPD) MIH recommendations examined the children between December 1, 2014 and June 30, 2015. Children were examined at their schools using a flashlight and mirror after receiving consent from parents/caregivers and assent from each child. Findings were recorded onto a standardized form by one of five trained examiners. Summary statistics were calculated, and bivariate analysis were done to identify factors associated with MIH. Results: A total of 375 children (average age =8.66 years, range 7-12) were examined, 60% females and 41% Hispanics. Overall, 36 (9.6%) of the children demonstrated findings consistent with the diagnosis of MIH. Among the teeth with MIH defects, severe defects were higher in lower molars. There were no statistically significant differences between those with and without MIH by sex, race/ethnicity, and socioeconomic status in this study. Conclusion: The study revealed that 9.6% of the children examined were affected by MIH. Future studies should focus on statewide and/or nationwide surveys in the United States to ascertain the extent and severity of the condition.
Collapse
Affiliation(s)
- Megan Davenport
- Pediatric Dentistry Residency Program, Children’s Hospital of Wisconsin, Milwaukee, WI53201, USA
| | - Andrew D Welles
- Marquette University School of Dentistry, Milwaukee, WI53233, USA
| | | | - Cesar Gonzalez
- Predoctoral Program in Pediatric Dentistry, Marquette University School of Dentistry, Milwaukee, WI53233, USA
| | - Christopher Okunseri
- Predoctoral Program in Dental Public Health, Marquette University School of Dentistry, Milwaukee, WI53233, USA
| | - Lori Barbeau
- Pediatric Dentistry Residency Program, Children’s Hospital of Wisconsin, Milwaukee, WI53201, USA
| | - Naveen K Bansal
- Department of Mathematics, Statistics, and Computer Science, Marquette University, Milwaukee, WI, USA
| | - Rodney J Vergotine
- College of Dental Medicine – Illinois [CDMI], Midwestern University, Downers Grove, IL, USA
| | - Brian D Hodgson
- Pediatric Dentistry Residency Program, Children’s Hospital of Wisconsin, Marquette University School of Dentistry, Milwaukee, WI, USA
| |
Collapse
|
14
|
Li J, Wang P, Gao J, Fei X, Liu Y, Ruan J. NaF Reduces KLK4 Gene Expression by Decreasing Foxo1 in LS8 Cells. Biol Trace Elem Res 2018; 186:498-504. [PMID: 29633120 DOI: 10.1007/s12011-018-1325-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Accepted: 03/22/2018] [Indexed: 10/17/2022]
Abstract
Decreased expression and increased phosphorylation of Forkhead box o1 (Foxo1) in ameloblasts were observed both in vivo and in vitro when treated by fluoride. The present study aims to investigate the possible relationship between Foxo1 and enamel matrix proteinases, matrix metalloproteinase 20 (MMP20), and kallikrein 4 (KLK4), in NaF-treated ameloblasts. Ameloblast-like cells (LS8 cells) were exposed to NaF at selected concentration (0/2 mM) for 24 h. Gene overexpression and silencing experiments were used to up- and down-regulate Foxo1 expression. The expression levels of Foxo1, MMP20, and KLK4 were detected by quantitative real-time PCR and western blot. Dual luciferase reporter assay was performed to evaluate the regulation of Foxo1 on the transcriptional activity of KLK4 promoter. The results showed that KLK4 expression was decreased in LS8 cells treated by NaF, while MMP20 expression was not changed. Foxo1 activation led to significantly up-regulation of KLK4 in LS8 cells under NaF condition. Knockout of Foxo1 markedly decreased klk4 expression in mRNA level, and intensified inhibition occurred in LS8 cells when combined with NaF treatment. However, the variation trend of MMP20 was not clear. Dual luciferase reporter assay showed that Foxo1 activation enhanced the transcriptional activity of KLK4 promoter. These findings suggest that the decrease of Foxo1 expression induced by high fluoride was a cause for low KLK4 expression.
Collapse
Affiliation(s)
- Juedan Li
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an, 710004, People's Republic of China
- Department of General Dentistry, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an, 710004, People's Republic of China
| | - Peng Wang
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an, 710004, People's Republic of China
| | - Jianghong Gao
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an, 710004, People's Republic of China
- Department of Preventive Dentistry, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an, 710004, People's Republic of China
| | - Xiuzhi Fei
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an, 710004, People's Republic of China
- Department of Preventive Dentistry, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an, 710004, People's Republic of China
| | - Yan Liu
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an, 710004, People's Republic of China
- Department of Preventive Dentistry, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an, 710004, People's Republic of China
| | - Jianping Ruan
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an, 710004, People's Republic of China.
- Department of Preventive Dentistry, College of Stomatology, Xi'an Jiaotong University, 98 XiWu Road, Xi'an, 710004, People's Republic of China.
| |
Collapse
|
15
|
da Cunha Coelho ASE, Mata PCM, Lino CA, Macho VMP, Areias CMFGP, Norton APMAP, Augusto APCM. Dental hypomineralization treatment: A systematic review. J ESTHET RESTOR DENT 2018; 31:26-39. [PMID: 30284749 DOI: 10.1111/jerd.12420] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 06/08/2018] [Accepted: 08/05/2018] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Defects in the maturation stage of amelogenesis result in a normal volume of enamel but insufficient mineralization, called hypomineralization. Molar-incisor hypomineralization (MIH), amelogenesis imperfecta and dental fluorosis (DF) are examples of such defects. OBJECTIVE To evaluate the effectiveness of the treatments applied to the different forms of dental hypomineralization. MATERIALS AND METHODS PubMed, Scopus, Cochrane Library, Web of Science, and Embase were screened. The research was limited to studies published in English, Spanish, and Portuguese, until May 30, 2018. The research question was formulated following the Population, Intervention, Comparison, Outcome strategy. The quality of the methodology of each article was evaluated employing the Cochrane Handbook for Systematic Reviews. RESULTS From the initial research, 7895 references were obtained, of which 33 were included in the systematic review. The following treatments were reported: desensitizing and remineralizing products, resin infiltration, restorations, fissure sealants, tooth bleaching, enamel microabrasion and calcium, and vitamins supplements. CONCLUSIONS Although the results are suggestive, there is a clear need for a greater uniformity of the methodologies, thus allowing for the development of clinical guidelines. Nevertheless, it was possible to identify several effective treatments for teeth with MIH (arginine pastes or fluoride varnishes) and DF (tooth bleaching and/or enamel microabrasion). CLINICAL SIGNIFICANCE Because MIH, amelogenesis imperfecta, and DF are commonly seen in dental daily practice, it is extremely important to analyze the literature regarding its treatment.
Collapse
Affiliation(s)
- Ana Sofia Estima da Cunha Coelho
- Dentistry Area, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,iCBR, Coimbra Institute of Clinical and Biomedical Research, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | | | - Carolina Alves Lino
- Dentistry Area, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | | | | | | | | |
Collapse
|
16
|
Ji M, Xiao L, Xu L, Huang S, Zhang D. How pH is regulated during amelogenesis in dental fluorosis. Exp Ther Med 2018; 16:3759-3765. [PMID: 30402142 DOI: 10.3892/etm.2018.6728] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 12/01/2017] [Indexed: 12/14/2022] Open
Abstract
Amelogenesis is a complicated process that concerns the interaction between growing hydroxyapatite crystals and extracellular proteins, which requires the tight regulation of pH. In dental fluorosis, the balance of pH regulation is broken, leading to abnormal mineralization. The current review focuses on the electrolyte transport processes associated with pH homeostasis, particularly regarding the changes in ion transporters that occur during amelogenesis, following exposure to excessive fluoride. Furthermore, the possible mechanism of fluorosis is discussed on the basis of acid hypothesis. There are two main methods by which F- accelerates crystal formation in ameloblasts. Firstly, it induces the release of protons, lowering the pH of the cell microenvironment. The decreased pH stimulates the upregulation of ion transporters, which attenuates further declines in the pH. Secondly, F- triggers an unknown signaling pathway, causing changes in the transcription of ion transporters and upregulating the expression of bicarbonate transporters. This results in the release of a large amount of bicarbonate from ameloblasts, which may neutralize the pH to form a microenvironment that favors crystal nucleation. The decreased pH stimulates the diffusion of F- into the cytoplasm of amelobalsts along the concentration gradient formed by the release of protons. The retention of F- causes a series of pathological changes, including oxidative and endoplasmic reticulum stress. If the buffering capacity of ameloblasts facing F- toxicity holds, normal mineralization occurs; however, if F- levels are high enough to overwhelm the buffering capacity of ameloblasts, abnormal mineralization occurs, leading to dental fluorosis.
Collapse
Affiliation(s)
- Mei Ji
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Lili Xiao
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Le Xu
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Shengyun Huang
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Dongsheng Zhang
- Department of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| |
Collapse
|
17
|
Malyshev IY, Runova GS, Poduraev YV, Mironov VA. [Natural amelogenesis and rationale for enamel regeneration by means of robotic bioprinting of tissues in situ]. STOMATOLOGII︠A︡ 2018; 97:58-64. [PMID: 29795109 DOI: 10.17116/stomat201897258-64] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- I Yu Malyshev
- Moscow State University of Medicine and Dentistry named after A.I. Evdokimov, Moscow, Russia, 127473
| | - G S Runova
- Moscow State University of Medicine and Dentistry named after A.I. Evdokimov, Moscow, Russia, 127473
| | - Yu V Poduraev
- Moscow State Technological University STANKIN, Moscow, Russia, 127055
| | - V A Mironov
- Biotechnology Research Laboratory '3D Bioprinting Solutions', Moscow, Russia, 115409
| |
Collapse
|
18
|
Rácz R, Földes A, Bori E, Zsembery Á, Harada H, Steward MC, DenBesten P, Bronckers ALJJ, Gerber G, Varga G. No Change in Bicarbonate Transport but Tight-Junction Formation Is Delayed by Fluoride in a Novel Ameloblast Model. Front Physiol 2017; 8:940. [PMID: 29375389 PMCID: PMC5770627 DOI: 10.3389/fphys.2017.00940] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 11/06/2017] [Indexed: 01/17/2023] Open
Abstract
We have recently developed a novel in vitro model using HAT-7 rat ameloblast cells to functionally study epithelial ion transport during amelogenesis. Our present aims were to identify key transporters of bicarbonate in HAT-7 cells and also to examine the effects of fluoride exposure on vectorial bicarbonate transport, cell viability, and the development of transepithelial resistance. To obtain monolayers, the HAT-7 cells were cultured on Transwell permeable filters. We monitored transepithelial resistance (TER) as an indicator of tight junction formation and polarization. We evaluated intracellular pH changes by microfluorometry using the fluorescent indicator BCECF. Activities of ion transporters were tested by withdrawal of various ions from the bathing medium, by using transporter specific inhibitors, and by activation of transporters with forskolin and ATP. Cell survival was estimated by alamarBlue assay. Changes in gene expression were monitored by qPCR. We identified the activity of several ion transporters, NBCe1, NHE1, NKCC1, and AE2, which are involved in intracellular pH regulation and vectorial bicarbonate and chloride transport. Bicarbonate secretion by HAT-7 cells was not affected by acute fluoride exposure over a wide range of concentrations. However, tight-junction formation was inhibited by 1 mM fluoride, a concentration which did not substantially reduce cell viability, suggesting an effect of fluoride on paracellular permeability and tight-junction formation. Cell viability was only reduced by prolonged exposure to fluoride concentrations greater than 1 mM. In conclusion, cultured HAT-7 cells are functionally polarized and are able to transport bicarbonate ions from the basolateral to the apical fluid spaces. Exposure to 1 mM fluoride has little effect on bicarbonate secretion or cell viability but delays tight-junction formation, suggesting a novel mechanism that may contribute to dental fluorosis.
Collapse
Affiliation(s)
- Róbert Rácz
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
| | - Anna Földes
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
| | - Erzsébet Bori
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
| | - Ákos Zsembery
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
| | | | - Martin C Steward
- School of Medical Sciences, University of Manchester, Manchester, United Kingdom
| | - Pamela DenBesten
- Department of Orofacial Sciences, University of California, San Francisco, San Francisco, CA, United States
| | - Antonius L J J Bronckers
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam, Netherlands
| | - Gábor Gerber
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Gábor Varga
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
| |
Collapse
|
19
|
Jalali R, Lodder JC, Zandieh-Doulabi B, Micha D, Melvin JE, Catalan MA, Mansvelder HD, DenBesten P, Bronckers A. The Role of Na:K:2Cl Cotransporter 1 (NKCC1/SLC12A2) in Dental Epithelium during Enamel Formation in Mice. Front Physiol 2017; 8:924. [PMID: 29209227 PMCID: PMC5702478 DOI: 10.3389/fphys.2017.00924] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 10/31/2017] [Indexed: 12/21/2022] Open
Abstract
Na+:K+:2Cl− cotransporters (NKCCs) belong to the SLC12A family of cation-coupled Cl− transporters. We investigated whether enamel-producing mouse ameloblasts express NKCCs. Transcripts for Nkcc1 were identified in the mouse dental epithelium by RT-qPCR and NKCC1 protein was immunolocalized in outer enamel epithelium and in the papillary layer but not the ameloblast layer. In incisors of Nkcc1-null mice late maturation ameloblasts were disorganized, shorter and the mineral density of the enamel was reduced by 10% compared to wild-type controls. Protein levels of gap junction protein connexin 43, Na+-dependent bicarbonate cotransporter e1 (NBCe1), and the Cl−-dependent bicarbonate exchangers SLC26A3 and SLC26A6 were upregulated in Nkcc1-null enamel organs while the level of NCKX4/SLC24A4, the major K+, Na+ dependent Ca2+ transporter in maturation ameloblasts, was slightly downregulated. Whole-cell voltage clamp studies on rat ameloblast-like HAT-7 cells indicated that bumetanide increased ion-channel activity conducting outward currents. Bumetanide also reduced cell volume of HAT-7 cells. We concluded that non-ameloblast dental epithelium expresses NKCC1 to regulate cell volume in enamel organ and provide ameloblasts with Na+, K+ and Cl− ions required for the transport of mineral- and bicarbonate-ions into enamel. Absence of functional Nkcc1 likely is compensated by other types of ion channels and ion transporters. The increased amount of Cx43 in enamel organ cells in Nkcc1-null mice suggests that these cells display a higher number of gap junctions to increase intercellular communication.
Collapse
Affiliation(s)
- Rozita Jalali
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam Movement Sciences, University of Amsterdam, VU University Amsterdam, Amsterdam, Netherlands.,Department of Functional Anatomy, Academic Centre for Dentistry Amsterdam (ACTA), MOVE Research Institute Amsterdam, University of Amsterdam, VU University Amsterdam, Amsterdam, Netherlands
| | - Johannes C Lodder
- Department Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, Netherlands
| | - Behrouz Zandieh-Doulabi
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam Movement Sciences, University of Amsterdam, VU University Amsterdam, Amsterdam, Netherlands
| | - Dimitra Micha
- Department of Clinical Genetics, VU University Medical Center, Amsterdam Movement Sciences, Netherlands
| | - James E Melvin
- Secretory Mechanisms and Dysfunction Section, NIDCR/NIH, Bethesda, MD, United States
| | - Marcelo A Catalan
- Secretory Mechanisms and Dysfunction Section, NIDCR/NIH, Bethesda, MD, United States.,Departamento de Ciencias Químicas y Farmaceúticas, Facultad de Ciencias de la Salud, Universidad Arturo Prat, Iquique, Chile
| | - Huibert D Mansvelder
- Department Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, Netherlands
| | - Pamela DenBesten
- Department of Orofacial Sciences, School of Dentistry, University of California, San Francisco, San Francisco, CA, United States
| | - Antonius Bronckers
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam Movement Sciences, University of Amsterdam, VU University Amsterdam, Amsterdam, Netherlands
| |
Collapse
|
20
|
Varga G, DenBesten P, Rácz R, Zsembery Á. Importance of bicarbonate transport in pH control during amelogenesis - need for functional studies. Oral Dis 2017; 24:879-890. [PMID: 28834043 DOI: 10.1111/odi.12738] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 08/13/2017] [Indexed: 12/27/2022]
Abstract
Dental enamel, the hardest mammalian tissue, is produced by ameloblasts. Ameloblasts show many similarities to other transporting epithelia although their secretory product, the enamel matrix, is quite different. Ameloblasts direct the formation of hydroxyapatite crystals, which liberate large quantities of protons that then need to be buffered to allow mineralization to proceed. Buffering requires a tight pH regulation and secretion of bicarbonate by ameloblasts. Many investigations have used immunohistochemical and knockout studies to determine the effects of these genes on enamel formation, but up till recently very little functional data were available for mineral ion transport. To address this, we developed a novel 2D in vitro model using HAT-7 ameloblast cells. HAT-7 cells can be polarized and develop functional tight junctions. Furthermore, they are able to accumulate bicarbonate ions from the basolateral to the apical fluid spaces. We propose that in the future, the HAT-7 2D system along with similar cellular models will be useful to functionally model ion transport processes during amelogenesis. Additionally, we also suggest that similar approaches will allow a better understanding of the regulation of the cycling process in maturation-stage ameloblasts, and the pH sensory mechanisms, which are required to develop sound, healthy enamel.
Collapse
Affiliation(s)
- G Varga
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
| | - P DenBesten
- Department of Orofacial Sciences, University of California, San Francisco, CA, USA
| | - R Rácz
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
| | - Á Zsembery
- Department of Oral Biology, Semmelweis University, Budapest, Hungary
| |
Collapse
|
21
|
Lacruz RS, Habelitz S, Wright JT, Paine ML. DENTAL ENAMEL FORMATION AND IMPLICATIONS FOR ORAL HEALTH AND DISEASE. Physiol Rev 2017; 97:939-993. [PMID: 28468833 DOI: 10.1152/physrev.00030.2016] [Citation(s) in RCA: 223] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 01/10/2017] [Accepted: 01/10/2017] [Indexed: 12/16/2022] Open
Abstract
Dental enamel is the hardest and most mineralized tissue in extinct and extant vertebrate species and provides maximum durability that allows teeth to function as weapons and/or tools as well as for food processing. Enamel development and mineralization is an intricate process tightly regulated by cells of the enamel organ called ameloblasts. These heavily polarized cells form a monolayer around the developing enamel tissue and move as a single forming front in specified directions as they lay down a proteinaceous matrix that serves as a template for crystal growth. Ameloblasts maintain intercellular connections creating a semi-permeable barrier that at one end (basal/proximal) receives nutrients and ions from blood vessels, and at the opposite end (secretory/apical/distal) forms extracellular crystals within specified pH conditions. In this unique environment, ameloblasts orchestrate crystal growth via multiple cellular activities including modulating the transport of minerals and ions, pH regulation, proteolysis, and endocytosis. In many vertebrates, the bulk of the enamel tissue volume is first formed and subsequently mineralized by these same cells as they retransform their morphology and function. Cell death by apoptosis and regression are the fates of many ameloblasts following enamel maturation, and what cells remain of the enamel organ are shed during tooth eruption, or are incorporated into the tooth's epithelial attachment to the oral gingiva. In this review, we examine key aspects of dental enamel formation, from its developmental genesis to the ever-increasing wealth of data on the mechanisms mediating ionic transport, as well as the clinical outcomes resulting from abnormal ameloblast function.
Collapse
Affiliation(s)
- Rodrigo S Lacruz
- Department of Basic Science and Craniofacial Biology, College of Dentistry, New York University, New York, New York; Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California; Department of Pediatric Dentistry, School of Dentistry, University of North Carolina, Chapel Hill, North Carolina; Herman Ostrow School of Dentistry, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, California
| | - Stefan Habelitz
- Department of Basic Science and Craniofacial Biology, College of Dentistry, New York University, New York, New York; Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California; Department of Pediatric Dentistry, School of Dentistry, University of North Carolina, Chapel Hill, North Carolina; Herman Ostrow School of Dentistry, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, California
| | - J Timothy Wright
- Department of Basic Science and Craniofacial Biology, College of Dentistry, New York University, New York, New York; Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California; Department of Pediatric Dentistry, School of Dentistry, University of North Carolina, Chapel Hill, North Carolina; Herman Ostrow School of Dentistry, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, California
| | - Michael L Paine
- Department of Basic Science and Craniofacial Biology, College of Dentistry, New York University, New York, New York; Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, San Francisco, California; Department of Pediatric Dentistry, School of Dentistry, University of North Carolina, Chapel Hill, North Carolina; Herman Ostrow School of Dentistry, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, California
| |
Collapse
|
22
|
Jalali R, Guy F, Ghazanfari S, Lyaruu D, van Ruijven L, DenBesten P, Martignon S, Castiblanco G, Bronckers ALJJ. Mineralization-defects are comparable in fluorotic impacted human teeth and fluorotic mouse incisors. Arch Oral Biol 2017; 83:214-221. [PMID: 28806687 DOI: 10.1016/j.archoralbio.2017.07.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 07/14/2017] [Accepted: 07/25/2017] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Fluoride excess of 0.05-0.07mgF/kgbw/day in water or food additives like salt is the principal cause of endemic dental fluorosis. How fluoride causes these defects is not clear yet. Recent studies in rodents suggest that development of enamel fluorosis is associated with insufficient neutralization of protons released during the formation of hypermineralized lines. DESIGN Here we examined whether hypermineralization could also be assessed by MicroCT in developing molar enamel of humans exposed to fluoride. RESULT Micro-CT analysis of hypomineralized enamel from human fluorotic molars graded by the Thylstrup-Fejerskov (TF) Index as III-IV showed weak hypermineralized lines and hypermineralized patches not seen in TF-I/II grade enamel. The mesio-distal sides of these molar teeth were significantly smaller (∼18%, p=0.02) than in TF-I/II teeth. CONCLUSION The patterns of changes observed in human fluorotic teeth were similar to those in fluorotic rodent incisors. The data are consistent with the hypothesis that also in developing human teeth fluoride-stimulated local acidification of enamel could be a mechanism for developing fluorotic enamel.
Collapse
Affiliation(s)
- Rozita Jalali
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam, University of Amsterdam, and MOVE Research Institute, VU University Amsterdam, Amsterdam, Netherlands.
| | - Franck Guy
- CNRS INEE UMR 7262 - IPHEP, Institut de Paléoprimatologie et Paléontologie Humaine, Evolution et Paléoenvironnements, Université de Poitiers - Faculté des Sciences, Poitiers, Cedex 9, France
| | - Samaneh Ghazanfari
- Department of Orthopaedic Surgery - VU Medical Centre, MOVE Research Institute Amsterdam, Amsterdam, Netherlands and the Aachen-Maastricht Institute for Biobased Materials, Faculty of Humanities and Sciences, Maastricht University, Maastricht, Netherlands
| | - Don Lyaruu
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam, University of Amsterdam, and MOVE Research Institute, VU University Amsterdam, Amsterdam, Netherlands
| | - Leo van Ruijven
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam, University of Amsterdam, and MOVE Research Institute, VU University Amsterdam, Amsterdam, Netherlands
| | - Pamela DenBesten
- Department of Orofacial Sciences, School of Dentistry, University of California, San Francisco, CA, 94143-0422, USA
| | - Stefania Martignon
- UNICA - Caries Research Unit, Research Vice-rectory, Universidad El Bosque, Bogotá, Colombia
| | - Gina Castiblanco
- UNICA - Caries Research Unit, Research Vice-rectory, Universidad El Bosque, Bogotá, Colombia
| | - Antonius L J J Bronckers
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam, University of Amsterdam, and MOVE Research Institute, VU University Amsterdam, Amsterdam, Netherlands
| |
Collapse
|
23
|
Lelis IMP, Molina GF, Souza C, Perez WB, Laure HJ, Rosa JC, Gerlach RF. Peptide Characterization of Mature Fluorotic and Control Human Enamel. Braz Dent J 2017; 27:66-71. [PMID: 27007349 DOI: 10.1590/0103-6440201600424] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 01/25/2016] [Indexed: 11/22/2022] Open
Abstract
Exposure to high fluoride levels during amelogenesis causes enamel fluorosis. This study aimed to determine and compare the amino acid sequences in the enamel of fluorotic and control teeth. This investigation included enamel samples obtained from erupted and non-erupted third molars with either TF grade 4-6 (n=7) fluorosis or no sign of fluorosis (controls, n=7). The samples were kept frozen at -20 °C until protein extraction. Samples were etched and processed with a cocktail of proteinase inhibitors and immediately analyzed. Matrix Assisted Laser Desorption/Ionization-Time-Of-Flight/Time-of-Flight Mass Spectrometry (MALDI-TOF/TOF) followed by MASCOT search aided the peptides analysis. The more abundant peptides bore the N-terminal amelogenin sequences WYQSIRPPYP (which is specific for the X-encoded amelogenin) and MPLPPHPGHPGYINF (which does not show sexual dimorphism) were not different in control or fluorotic enamel. There was no missing proteolytic cleavage in the fluorotic samples, which suggested that the increased amount of protein described in fluorotic enamel did not stem from the decreased ability of proteinases to cleave the proteins in humans. This study showed how to successfully obtain peptide from superficial enamel. A relatively low number of teeth was sufficient to provide good data on the actual peptides found in mature enamel.
Collapse
Affiliation(s)
- Isabel Maria Porto Lelis
- Department of Morphology, Dental School of Piracicaba, Universidade Estadual de Campinas, Piracicaba, SP, Brazil
| | - Gabriela F Molina
- Departament of Morphology, Physiology and Basic Patology, Dental School of Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | | | - Walter B Perez
- Department of Stomatology, Health Sciences Center, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Helen J Laure
- Departament of Cellular and Molecular Biology and Bio-Agents Pathogens, Medical School of Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - José C Rosa
- Departament of Cellular and Molecular Biology and Bio-Agents Pathogens, Medical School of Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - Raquel F Gerlach
- Departament of Morphology, Physiology and Basic Patology, Dental School of Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| |
Collapse
|
24
|
Bronckers AL, Lyaruu DM. Magnesium, pH regulation and modulation by mouse ameloblasts exposed to fluoride. Bone 2017; 94:56-64. [PMID: 27744011 DOI: 10.1016/j.bone.2016.10.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 10/05/2016] [Accepted: 10/10/2016] [Indexed: 12/25/2022]
Abstract
Supraoptimal intake of fluoride (F) induces structural defects in forming enamel, dentin and bone and increases the risk of bone fractures. In comparison to bone and dentin is formation of enamel most sensitive to low levels of F and the degree of enamel fluorosis depends on the mouse strain. What molecular mechanism is responsible for these differences in sensitivity is unclear. Maturation ameloblasts transport bicarbonates into enamel in exchange for Cl- to buffer protons released by forming apatites. We proposed that F-enhanced mineral deposition releases excess of protons that will affect mineralization in forming enamel. In this study we tested the hypothesis that increased sensitivity to F is associated with a reduced capacity of ameloblasts to buffer acids. Quantified electron probe microanalysis showed that enamel of F-sensitive C57Bl mice contained the same levels of Cl- as enamel of F-resistant FVB mice. Enamel of C57Bl mice was less mineral dense, contained less Ca but more Mg and K. Ameloblast modulation was much more impaired than in FVB mice. In enamel of FVB mice the levels of Mg correlated negative with Ca (r=-0.57, p=0.01) and with the Ca/P molar ratio (r=-0.32, p=0.53). In moderate and high acidic enamel the correlations between Mg and Ca/P ratio were strong (r=-0.75, p=0.08) to very strong negative (r=-0.98, p=0.0020), respectively. Correlations in enamel between F and Ca were (weak) negative but between F and Ca/P very high positive (r=+0.95, p=0.003) in high acidic enamel and less positive (r=0.45, p=0.27) in moderate acidic fluorotic enamel (r=0.45, p=0.27). Similar correlations between Mg and Ca/P or F and Ca/P were found in dentin and bone of fluorotic and Cftr null mice. These data are consistent with the concept that Mg delays but F increases maturation of crystals particularly when enamel is acidic. The sensitivity of forming enamel to F likely is due to the sensitivity of pH cycling to acidification of enamel associated with F-induced release of protons.
Collapse
Affiliation(s)
- Antonius Ljj Bronckers
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, MOVE Research Institute, Amsterdam, The Netherlands.
| | - Donacian M Lyaruu
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, MOVE Research Institute, Amsterdam, The Netherlands
| |
Collapse
|
25
|
Bronckers ALJJ, Jalali R, Lytton J. Reduced Protein Expression of the Na +/Ca 2++K +-Exchanger (SLC24A4) in Apical Plasma Membranes of Maturation Ameloblasts of Fluorotic Mice. Calcif Tissue Int 2017; 100:80-86. [PMID: 27752731 PMCID: PMC5215084 DOI: 10.1007/s00223-016-0197-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Accepted: 10/03/2016] [Indexed: 02/07/2023]
Abstract
Exposure of forming enamel to fluoride results into formation of hypomineralized enamel. We tested whether enamel hypomineralization was caused by lower expression of the NCKX4/SLC24A4 Ca2+-transporter by ameloblasts. Three commercial antibodies against NCKX4 were tested on enamel organs of wild-type and Nckx4-null mice, one of which (a mouse monoclonal) was specific. This antibody gave a prominent staining of the apical plasma membranes of maturation ameloblasts, starting at early maturation. The layer of immuno-positive ameloblasts contained narrow gaps without immunostaining or with reduced staining. In fluorotic mouse incisors, the quantity of NCKX4 protein in ameloblasts as assessed by western blotting was not different from that in non-fluorotic ameloblasts. However, immunostaining of the apical plasma membranes of fluorotic ameloblasts was strongly reduced or absent suggesting that trafficking of NCKX4 to the apical membrane was strongly reduced. Exposure to fluoride may reduce NCKX4-mediated transport of Ca2+ by maturation stage ameloblasts which delays ameloblast modulation and reduces enamel mineralization.
Collapse
Affiliation(s)
- A L J J Bronckers
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), MOVE Research Institute, University of Amsterdam and VU University Amsterdam, Gustav Mahlerlaan 3004, 1081LA, Amsterdam, The Netherlands.
| | - R Jalali
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), MOVE Research Institute, University of Amsterdam and VU University Amsterdam, Gustav Mahlerlaan 3004, 1081LA, Amsterdam, The Netherlands
| | - J Lytton
- Department of Biochemistry and Molecular Biology, Hotchkiss Brain Institute and Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4Z6, Canada
| |
Collapse
|
26
|
Zhang Y, Zhang Y, Zheng X, Xu R, He H, Duan X. Grading and quantification of dental fluorosis in zebrafish larva. Arch Oral Biol 2016; 70:16-23. [DOI: 10.1016/j.archoralbio.2016.05.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 01/25/2016] [Accepted: 05/30/2016] [Indexed: 12/15/2022]
|
27
|
Bronckers ALJJ, Lyaruu DM, Jalali R, DenBesten PK. Buffering of protons released by mineral formation during amelogenesis in mice. Eur J Oral Sci 2016; 124:415-425. [PMID: 27422589 DOI: 10.1111/eos.12287] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/01/2016] [Indexed: 12/17/2022]
Abstract
Regulation of pH by ameloblasts during amelogenesis is critical for enamel mineralization. We examined the effects of reduced bicarbonate secretion and the presence or absence of amelogenins on ameloblast modulation and enamel mineralization. To that end, the composition of fluorotic and non-fluorotic enamel of several different mouse mutants, including enamel of cystic fibrosis transmembrane conductance regulator-deficient (Cftr null), anion exchanger-2-deficient (Ae2a,b null), and amelogenin-deficient (Amelx null) mice, was determined by quantitative X-ray microanalysis. Correlation analysis was carried out to compare the effects of changes in the levels of sulfated-matrix (S) and chlorine (Cl; for bicarbonate secretion) on mineralization and modulation. The chloride (Cl- ) levels in forming enamel determined the ability of ameloblasts to modulate, remove matrix, and mineralize enamel. In general, the lower the Cl- content, the stronger the negative effects. In Amelx-null mice, modulation was essentially normal and the calcium content was reduced least. Retention of amelogenins in enamel of kallikrein-4-deficient (Klk4-null) mice resulted in decreased mineralization and reduced the length of the first acid modulation band without changing the total length of all acidic bands. These data suggest that buffering by bicarbonates is critical for modulation, matrix removal and enamel mineralization. Amelogenins also act as a buffer but are not critical for modulation.
Collapse
Affiliation(s)
- Antonius L J J Bronckers
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam, Amsterdam, the Netherlands. .,VU University Amsterdam, MOVE Research Institute, Amsterdam, the Netherlands.
| | - Don M Lyaruu
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam, Amsterdam, the Netherlands
| | - Rozita Jalali
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam, Amsterdam, the Netherlands
| | - Pamela K DenBesten
- Department of Oral Sciences, University of California in San Francisco, CA, USA
| |
Collapse
|
28
|
Kierdorf U, Death C, Hufschmid J, Witzel C, Kierdorf H. Developmental and Post-Eruptive Defects in Molar Enamel of Free-Ranging Eastern Grey Kangaroos (Macropus giganteus) Exposed to High Environmental Levels of Fluoride. PLoS One 2016; 11:e0147427. [PMID: 26895178 PMCID: PMC4760926 DOI: 10.1371/journal.pone.0147427] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 01/04/2016] [Indexed: 11/18/2022] Open
Abstract
Dental fluorosis has recently been diagnosed in wild marsupials inhabiting a high-fluoride area in Victoria, Australia. Information on the histopathology of fluorotic marsupial enamel has thus far not been available. This study analyzed the developmental and post-eruptive defects in fluorotic molar enamel of eastern grey kangaroos (Macropus giganteus) from the same high-fluoride area using light microscopy and backscattered electron imaging in the scanning electron microscope. The fluorotic enamel exhibited a brownish to blackish discolouration due to post-eruptive infiltration of stains from the oral cavity and was less resistant to wear than normally mineralized enamel of kangaroos from low-fluoride areas. Developmental defects of enamel included enamel hypoplasia and a pronounced hypomineralization of the outer (sub-surface) enamel underneath a thin rim of well-mineralized surface enamel. While the hypoplastic defects denote a disturbance of ameloblast function during the secretory stage of amelogenesis, the hypomineralization is attributed to an impairment of enamel maturation. In addition to hypoplastic defects, the fluorotic molars also exhibited numerous post-eruptive enamel defects due to the flaking-off of portions of the outer, hypomineralized enamel layer during mastication. The macroscopic and histopathological lesions in fluorotic enamel of M. giganteus match those previously described for placental mammals. It is therefore concluded that there exist no principal differences in the pathogenic mechanisms of dental fluorosis between marsupial and placental mammals. The regular occurrence of hypomineralized, opaque outer enamel in the teeth of M. giganteus and other macropodids must be considered in the differential diagnosis of dental fluorosis in these species.
Collapse
Affiliation(s)
- Uwe Kierdorf
- Department of Biology, University of Hildesheim, Hildesheim, Germany
- * E-mail:
| | - Clare Death
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria, Australia
| | - Jasmin Hufschmid
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria, Australia
| | - Carsten Witzel
- Department of Biology, University of Hildesheim, Hildesheim, Germany
| | - Horst Kierdorf
- Department of Biology, University of Hildesheim, Hildesheim, Germany
| |
Collapse
|
29
|
Escobar-García D, Mejía-Saavedra J, Jarquín-Yáñez L, Molina-Frechero N, Pozos-Guillén A. Collagenase 1A2 (COL1A2) gene A/C polymorphism in relation to severity of dental fluorosis. Community Dent Oral Epidemiol 2015; 44:162-8. [DOI: 10.1111/cdoe.12201] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 10/09/2015] [Indexed: 01/11/2023]
Affiliation(s)
- Diana Escobar-García
- Laboratorio de Ciencias Básicas; Facultad de Estomatología; Universidad Autónoma de San Luis Potosí; San Luis Potosí México
| | - Jesús Mejía-Saavedra
- Centro de Investigación Aplicada en Ambiente y Salud (CIACYT-Facultad de Medicina) Universidad Autónoma de San Luis Potosí; San Luis Potosí México
| | - Lizet Jarquín-Yáñez
- Centro de Investigación Aplicada en Ambiente y Salud (CIACYT-Facultad de Medicina) Universidad Autónoma de San Luis Potosí; San Luis Potosí México
| | - Nelly Molina-Frechero
- División de Ciencias Biológicas y de la Salud; Universidad Autónoma Metropolitana; México D.F. México
| | - Amaury Pozos-Guillén
- Laboratorio de Ciencias Básicas; Facultad de Estomatología; Universidad Autónoma de San Luis Potosí; San Luis Potosí México
| |
Collapse
|
30
|
Bronckers ALJJ, Lyaruu D, Jalali R, Medina JF, Zandieh-Doulabi B, DenBesten PK. Ameloblast Modulation and Transport of Cl⁻, Na⁺, and K⁺ during Amelogenesis. J Dent Res 2015; 94:1740-7. [PMID: 26403673 DOI: 10.1177/0022034515606900] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Ameloblasts express transmembrane proteins for transport of mineral ions and regulation of pH in the enamel space. Two major transporters recently identified in ameloblasts are the Na(+)K(+)-dependent calcium transporter NCKX4 and the Na(+)-dependent HPO4 (2-) (Pi) cotransporter NaPi-2b. To regulate pH, ameloblasts express anion exchanger 2 (Ae2a,b), chloride channel Cftr, and amelogenins that can bind protons. Exposure to fluoride or null mutation of Cftr, Ae2a,b, or Amelx each results in formation of hypomineralized enamel. We hypothesized that enamel hypomineralization associated with disturbed pH regulation results from reduced ion transport by NCKX4 and NaPi-2b. This was tested by correlation analyses among the levels of Ca, Pi, Cl, Na, and K in forming enamel of mice with null mutation of Cftr, Ae2a,b, and Amelx, according to quantitative x-ray electron probe microanalysis. Immunohistochemistry, polymerase chain reaction analysis, and Western blotting confirmed the presence of apical NaPi-2b and Nckx4 in maturation-stage ameloblasts. In wild-type mice, K levels in enamel were negatively correlated with Ca and Cl but less negatively or even positively in fluorotic enamel. Na did not correlate with P or Ca in enamel of wild-type mice but showed strong positive correlation in fluorotic and nonfluorotic Ae2a,b- and Cftr-null enamel. In hypomineralizing enamel of all models tested, 1) Cl(-) was strongly reduced; 2) K(+) and Na(+) accumulated (Na(+) not in Amelx-null enamel); and 3) modulation was delayed or blocked. These results suggest that a Na(+)K(+)-dependent calcium transporter (likely NCKX4) and a Na(+)-dependent Pi transporter (potentially NaPi-2b) located in ruffle-ended ameloblasts operate in a coordinated way with the pH-regulating machinery to transport Ca(2+), Pi, and bicarbonate into maturation-stage enamel. Acidification and/or associated physicochemical/electrochemical changes in ion levels in enamel fluid near the apical ameloblast membrane may reduce the transport activity of mineral transporters, which results in hypomineralization.
Collapse
Affiliation(s)
- A L J J Bronckers
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam, University of Amsterdam, and MOVE Research Institute, VU University Amsterdam, Amsterdam, Netherlands
| | - D Lyaruu
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam, University of Amsterdam, and MOVE Research Institute, VU University Amsterdam, Amsterdam, Netherlands
| | - R Jalali
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam, University of Amsterdam, and MOVE Research Institute, VU University Amsterdam, Amsterdam, Netherlands
| | - J F Medina
- Division of Gene Therapy and Hepatology, School of Medicine/CIMA, University of Navarra, and CIBERehd, Pamplona, Spain
| | - B Zandieh-Doulabi
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam, University of Amsterdam, and MOVE Research Institute, VU University Amsterdam, Amsterdam, Netherlands
| | - P K DenBesten
- Department of Oral Sciences, University of California, San Francisco, CA, USA
| |
Collapse
|
31
|
Abstract
Enamel is unique. It is the only epithelial-derived mineralized tissue in mammals and has a distinct micro- and nanostructure with nanofibrous apatite crystals as building blocks. It is synthesized by a highly specialized cell, the ameloblast, which secretes matrix proteins with little homology to any other known amino acid sequence, but which is composed of a primary structure that makes it competent to self-assemble and control apatite crystal growth at the nanometer scale. The end-product of ameloblast activity is a marvel of structural engineering: a material optimized to provide the tooth with maximum biting force, withstanding millions of cycles of loads without catastrophic failure, while also protecting the dental pulp from bacterial attack. This review attempts to bring into context the mechanical behavior of enamel with the developmental process of amelogenesis and structural development, since they are linked to tissue function, and the importance of controlling calcium phosphate mineralization at the nanometer scale. The origins of apatite nanofibers, the development of a stiffness gradient, and the biological processes responsible for the synthesis of a hard and fracture-resistant dental tissue are discussed with reference to the evolution of enamel from a fibrous composite to a complex, tough, and damage-tolerant coating on dentin.
Collapse
Affiliation(s)
- S Habelitz
- Preventive and Restorative Dental Sciences, University of California, San Francisco, CA, USA
| |
Collapse
|
32
|
Nakayama Y, Holcroft J, Ganss B. Enamel Hypomineralization and Structural Defects in Amelotin-deficient Mice. J Dent Res 2015; 94:697-705. [PMID: 25715379 DOI: 10.1177/0022034514566214] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Amelotin (AMTN) is a relatively recently discovered enamel protein that is predominantly expressed by ameloblasts during the maturation stage of amelogenesis and is present at lower levels in the junctional epithelium of erupted teeth. Previous studies have suggested a function of this protein in enamel mineralization and cell attachment. Genetic mouse models have been instrumental in defining the role of many enamel-related proteins, but a genetic mouse model lacking the Amtn gene has not been reported. Here, we describe the generation of amelotin-deficient mice and the analysis of their enamel phenotype in comparison with that of wild-type animals. Ablation of AMTN expression resulted in mechanically inferior enamel of mandibular incisors that showed chipping and fractures at the incisal edge. Enamel mineralization was delayed, resulting in hypomineralized inner enamel and structural defects in the outer enamel. Erupted enamel close to the gingival margin showed increased surface roughness. The expression levels of the enamel matrix proteins AMEL, AMBN, ENAM, and ODAM and the enamel proteases MMP-20 and KLK-4 were not significantly altered, although the expression of KLK-4 was delayed. The morphology of ameloblasts showing prominent Tomes' processes during the secretory stage was not altered, and there was no indication of disruption of cell structures or activities, but a residual layer, presumably consisting of organic material, remained at the enamel surface close to the gingival margin. The integrity of the dentogingival attachment at the junctional epithelium appeared unaffected by AMTN deficiency. These observations indicate that AMTN plays a subtle yet critical role in enamel biomineralization, particularly during the establishment of the outer and surface enamel layers. This role appears to be largely independent of other enamel proteins.
Collapse
Affiliation(s)
- Y Nakayama
- Department of Periodontology, Nihon University School of Dentistry at Matsudo, Chiba, Japan Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
| | - J Holcroft
- Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
| | - B Ganss
- Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
33
|
Abstract
In this chapter the basic premises, the recent findings and the future challenges in the use of amelogenin for enamel tissue engineering are being discoursed on. Results emerging from the experiments performed to assess the fundamental physicochemical mechanisms of the interaction of amelogenin, the main protein of the enamel matrix, and the growing crystals of apatite, are mentioned, alongside a moderately comprehensive literature review of the subject at hand. The clinical importance of understanding this protein/mineral interaction at the nanoscale are highlighted as well as the potential for tooth enamel to act as an excellent model system for studying some of the essential aspects of biomineralization processes in general. The dominant paradigm stating that amelogenin directs the uniaxial growth of apatite crystals in enamel by slowing down the growth of (hk0) faces on which it adheres is being questioned based on the results demonstrating the ability of amelogenin to promote the nucleation and crystal growth of apatite under constant titration conditions designed to mimic those present in the developing enamel matrix. The role of numerous minor components of the enamel matrix is being highlighted as essential and impossible to compensate for by utilizing its more abundant ingredients only. It is concluded that the three major aspects of amelogenesis outlined hereby--(1) the assembly of amelogenin and other enamel matrix proteins, (2) the proteolytic activity, and (3) crystallization--need to be in precise synergy with each other in order for the grounds for the proper imitation of amelogenesis in the lab to be created.
Collapse
Affiliation(s)
- Vuk Uskoković
- Advanced Materials and Nanobiotechnology Laboratory, Department of Bioengineering, University of Illinois, Chicago, IL, USA.
| |
Collapse
|
34
|
Bronckers ALJJ, Lyaruu DM, Guo J, Bijvelds MJC, Bervoets TJM, Zandieh-Doulabi B, Medina JF, Li Z, Zhang Y, DenBesten PK. Composition of mineralizing incisor enamel in cystic fibrosis transmembrane conductance regulator-deficient mice. Eur J Oral Sci 2014; 123:9-16. [PMID: 25557910 DOI: 10.1111/eos.12163] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/28/2014] [Indexed: 12/25/2022]
Abstract
Formation of crystals in the enamel space releases protons that need to be buffered to sustain mineral accretion. We hypothesized that apical cystic fibrosis transmembrane conductance regulator (CFTR) in maturation ameloblasts transduces chloride into forming enamel as a critical step to secrete bicarbonates. We tested this by determining the calcium, chloride, and fluoride levels in developing enamel of Cftr-null mice by quantitative electron probe microanalysis. Maturation-stage enamel from Cftr-null mice contained less chloride and calcium than did wild-type enamel, was more acidic when stained with pH dyes ex vivo, and formed no fluorescent modulation bands after in vivo injection of the mice with calcein. To acidify the enamel further we exposed Cftr-null mice to fluoride in drinking water to stimulate proton release during formation of hypermineralized lines. In Cftr-deficient mice, fluoride further lowered enamel calcium without further reducing chloride levels. The data support the view that apical CFTR in maturation ameloblasts tranduces chloride into developing enamel as part of the machinery to buffer protons released during mineral accretion.
Collapse
Affiliation(s)
- Antonius L J J Bronckers
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), MOVE Research Institute, University of Amsterdam and VU University Amsterdam, Amsterdam, the Netherlands
| | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Guo J, Lyaruu DM, Takano Y, Gibson CW, DenBesten PK, Bronckers ALJJ. Amelogenins as potential buffers during secretory-stage amelogenesis. J Dent Res 2014; 94:412-20. [PMID: 25535204 DOI: 10.1177/0022034514564186] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Amelogenins are the most abundant protein species in forming dental enamel, taken to regulate crystal shape and crystal growth. Unprotonated amelogenins can bind protons, suggesting that amelogenins could regulate the pH in enamel in situ. We hypothesized that without amelogenins the enamel would acidify unless ameloblasts were buffered by alternative ways. To investigate this, we measured the mineral and chloride content in incisor enamel of amelogenin-knockout (AmelX(-/-)) mice and determined the pH of enamel by staining with methyl-red. Ameloblasts were immunostained for anion exchanger-2 (Ae2), a transmembrane pH regulator sensitive for acid that secretes bicarbonate in exchange for chloride. The enamel of AmelX(-/-) mice was 10-fold thinner, mineralized in the secretory stage 1.8-fold more than wild-type enamel and containing less chloride (suggesting more bicarbonate secretion). Enamel of AmelX(-/-) mice stained with methyl-red contained no acidic bands in the maturation stage as seen in wild-type enamel. Secretory ameloblasts of AmelX(-/-) mice, but not wild-type mice, were immunopositive for Ae2, and stained more intensely in the maturation stage compared with wild-type mice. Exposure of AmelX(-/-) mice to fluoride enhanced the mineral content in the secretory stage, lowered chloride, and intensified Ae2 immunostaining in the enamel organ in comparison with non-fluorotic mutant teeth. The results suggest that unprotonated amelogenins may regulate the pH of forming enamel in situ. Without amelogenins, Ae2 could compensate for the pH drop associated with crystal formation.
Collapse
Affiliation(s)
- J Guo
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, MOVE Research Institute, Amsterdam, the Netherlands
| | - D M Lyaruu
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, MOVE Research Institute, Amsterdam, the Netherlands
| | - Y Takano
- Section of Biostructural Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - C W Gibson
- Department of Anatomy and Cell Biology, University of Pennsylvania School of Dental Medicine, Philadelphia, PA, USA
| | - P K DenBesten
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of California in San Francisco, CA, USA
| | - A L J J Bronckers
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, MOVE Research Institute, Amsterdam, the Netherlands
| |
Collapse
|
36
|
Ganss B, Abbarin N. Maturation and beyond: proteins in the developmental continuum from enamel epithelium to junctional epithelium. Front Physiol 2014; 5:371. [PMID: 25309457 PMCID: PMC4174742 DOI: 10.3389/fphys.2014.00371] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 09/08/2014] [Indexed: 12/23/2022] Open
Abstract
Enamel, covering the surface of teeth, is the hardest substance in mammals. It is designed to last a lifetime in spite of severe environmental challenges. Enamel is formed in a biomineralization process that is essentially divided into secretory and maturation stages. While the molecular events of enamel formation during the secretory stage have been elucidated to some extent, the mechanisms of enamel maturation are less defined, and little is known about the molecules present beyond the maturation stage. Several genes, all located within the secreted calcium-binding phosphoprotein (SCPP) gene cluster, were recently shown to be expressed during the developmental continuum from maturation stage ameloblasts to junctional epithelium (JE). This review introduces four such genes and their protein products, and presents our current state of knowledge on their roles, primarily in enamel formation and JE biology. The discovery of these proteins, and a more detailed analysis of their biological functions, will likely contribute to a more thorough understanding of the molecular mechanisms of enamel maturation and dentogingival attachment.
Collapse
Affiliation(s)
- Bernhard Ganss
- Matrix Dynamics Group, Mineralized Tissue Lab, Faculty of Dentistry, University of Toronto Toronto, ON, Canada
| | - Nastaran Abbarin
- Matrix Dynamics Group, Mineralized Tissue Lab, Faculty of Dentistry, University of Toronto Toronto, ON, Canada
| |
Collapse
|
37
|
Pugach MK, Gibson CW. Analysis of enamel development using murine model systems: approaches and limitations. Front Physiol 2014; 5:313. [PMID: 25278900 PMCID: PMC4166228 DOI: 10.3389/fphys.2014.00313] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 08/01/2014] [Indexed: 11/24/2022] Open
Abstract
A primary goal of enamel research is to understand and potentially treat or prevent enamel defects related to amelogenesis imperfecta (AI). Rodents are ideal models to assist our understanding of how enamel is formed because they are easily genetically modified, and their continuously erupting incisors display all stages of enamel development and mineralization. While numerous methods have been developed to generate and analyze genetically modified rodent enamel, it is crucial to understand the limitations and challenges associated with these methods in order to draw appropriate conclusions that can be applied translationally, to AI patient care. We have highlighted methods involved in generating and analyzing rodent enamel and potential approaches to overcoming limitations of these methods: (1) generating transgenic, knockout, and knockin mouse models, and (2) analyzing rodent enamel mineral density and functional properties (structure and mechanics) of mature enamel. There is a need for a standardized workflow to analyze enamel phenotypes in rodent models so that investigators can compare data from different studies. These methods include analyses of gene and protein expression, developing enamel histology, enamel pigment, degree of mineralization, enamel structure, and mechanical properties. Standardization of these methods with regard to stage of enamel development and sample preparation is crucial, and ideally investigators can use correlative and complementary techniques with the understanding that developing mouse enamel is dynamic and complex.
Collapse
Affiliation(s)
- Megan K Pugach
- Department of Mineralized Tissue Biology, The Forsyth Institute, Harvard School of Dental Medicine, Harvard University Cambridge, MA, USA
| | - Carolyn W Gibson
- Department of Anatomy and Cell Biology, School of Dental Medicine, University of Pennsylvania Philadelphia, PA, USA
| |
Collapse
|
38
|
Jalali R, Guo J, Zandieh-Doulabi B, Bervoets TJM, Paine ML, Boron WF, Parker MD, Bijvelds MJC, Medina JF, DenBesten PK, Bronckers ALJJ. NBCe1 (SLC4A4) a potential pH regulator in enamel organ cells during enamel development in the mouse. Cell Tissue Res 2014; 358:433-42. [PMID: 25012520 DOI: 10.1007/s00441-014-1935-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 05/23/2014] [Indexed: 12/11/2022]
Abstract
During the formation of dental enamel, maturation-stage ameloblasts express ion-transporting transmembrane proteins. The SLC4 family of ion-transporters regulates intra- and extracellular pH in eukaryotic cells by cotransporting HCO3 (-) with Na(+). Mutation in SLC4A4 (coding for the sodium-bicarbonate cotransporter NBCe1) induces developmental defects in human and murine enamel. We have hypothesized that NBCe1 in dental epithelium is engaged in neutralizing protons released during crystal formation in the enamel space. We immunolocalized NBCe1 protein in wild-type dental epithelium and examined the effect of the NBCe1-null mutation on enamel formation in mice. Ameloblasts expressed gene transcripts for NBCe1 isoforms B/D/C/E. In wild-type mice, weak to moderate immunostaining for NBCe1 with antibodies that recognized isoforms A/B/D/E and isoform C was seen in ameloblasts at the secretory stage, with no or low staining in the early maturation stage but moderate to high staining in the late maturation stage. The papillary layer showed the opposite pattern being immunostained prominently at the early maturation stage but with gradually less staining at the mid- and late maturation stages. In NBCe1 (-/-) mice, the ameloblasts were disorganized, the enamel being thin and severely hypomineralized. Enamel organs of CFTR (-/-) and AE2a,b (-/-) mice (CFTR and AE2 are believed to be pH regulators in ameloblasts) contained higher levels of NBCe1 protein than wild-type mice. Thus, the expression of NBCe1 in ameloblasts and the papillary layer cell depends on the developmental stage and possibly responds to pH changes.
Collapse
Affiliation(s)
- R Jalali
- Department of Oral Cell Biology, Academic Centre for Dentistry at Amsterdam (ACTA), Vrije Universiteit, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands,
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|