Cementoblasts
The dental keepers
Credit: Art by Nelli Aghekyan. Set in motion by Dr. Emanuele Petretto. Words by Dr. Suruchi Poddar. Project Coordinator: Dr. Masia Maksymowicz. Series Director: Dr. Radhika Patnala
#Extraordinarycelltypes #sciart #lifescience
Cementoblasts: the tooth fairies
Just as the tooth fairy holds a special place in every child’s life encouraging them to take care of their teeth in exchange for a small reward, cementoblasts act as tooth fairies by serving as a shield and protecting the teeth throughout development and into adulthood (1). Cementoblasts arise from the mesenchymal dental follicles around the root of a tooth and produce the mineralized tissue called cementum via the process of cementogenesis (2). As the name suggests, cementum (predominantly collagen and hydroxyapatite) acts as the gluing substance that cements or connects the periodontal tissues (tissues surrounding the gum and teeth) to the tooth (3).
The process of cementogenesis majorly revolves around the distribution of cementum around the neck of the root of the tooth to the apex. Cementoblasts play a crucial role in the dispersal of cementum through different layers of a tooth. The organic matrix or the ground substance is disseminated by cementoblasts with the help of collagenous fibers. These fibers crystallize the hydroxyapatite, a naturally occurring calcium mineral, and initiate the mineralization of cementum. Cementum acts as a bridge between the dentin, the layer immediately below the enamel, and the bony alveolar layer. The collagen fibers connect cementum to dentin and the Sharpey’s fibers (connective tissue fibers) link the alveolar bone to cementum (4). The stunning orchestration of all the above elements helps in proper formation, development and maintenance of the tooth throughout the lifetime of an individual.
The rise of cementoblasts
Although the origin of cementoblasts is not fully understood, there are several hypotheses that attempt to explain it. The concept of classical mesenchymal hypothesis assumes the origination of cementoblasts from the mesenchymal dental follicle cells whereas in an alternative hypothesis of epithelial-mesenchymal transition (EMT) the epithelial sheath cells are believed to transdifferentiate into cementoblasts (5). The alternative EMT hypothesis was first proposed by a pediatric dentist, Huw Thomas, who discovered phenotypic changes in the shape of epithelial sheath cells into mesenchymal-like. Based on the fact that cells of both phenotypes co-expressed vimentin and keratin proteins, characteristic of epithelial and mesenchymal cells, Thomas suggested that epithelial sheath cells were transformed into mesenchymal cementoblasts (6). However, it was open to doubt that the cementoblasts (produce cementum) and cementocytes (maintain cementum) were misidentified as epithelial sheath cells and mesenchymal cementoblasts giving an impression of them undergoing EMT (7). On the other hand, there have been findings (8,9,10) that support the classical mesenchymal hypothesis and show no evidence of the alternative EMT. In conclusion, the classical mesenchymal theory is widely accepted by scientists.
Diseases associated with cementoblasts
Periodontal diseases (associated with teeth and their surrounding tissues) are amongst the most common diseases in the world. Although the reasons for their emergence are very common, such as poor brushing and flossing style or not maintaining proper dental hygiene, their consequences could be unusual, resulting in disruption of the enamel and eventual tooth loss. Cementoblastoma is one such uncommon disease of young adults that affects the dental machinery responsible for tooth formation and development (11). It is a benign odontogenic mesenchymal tumor associated with the roots of the teeth and composed of swollen cementoblasts in abundance. Clinical symptoms include swelling in the bone, expansion and pain. The only available treatment is removal of the lesion and extraction of the affected tooth (11). More prevalent dental problems include periodontitis and ankylosis. A person can be infected with periodontitis alone or as a comorbidity with other medical conditions. Periodontitis is a well-known comorbidity in patients suffering from chronic kidney disease (CKD), because of the changes in the ionic concentrations of saliva in CKD patients (12). Periodontitis is characterized by the dysfunction in alveolar bone, cementum and other connective tissues (13). Treatment of periodontitis is challenged by the regeneration capacity of the periodontal structures. Lack of blood vessels and cells in the cementum delays its mineralization process which can be overcome by elevating the capabilities of cementoblasts to further expedite the wound healing and regenerative quality of cementum mineralization (12).
Recognizing and appreciating the labs working in this space
- Ono and Ono Laboratory, The University of Texas Health Science Center at Houston, USA. https://dentistry.uth.edu/research/labs/sod-lab?id=e811089b-2c1c-4054-a6eb-2cc7e10f5a8a
- Sharpe Group, Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral & Craniofacial Sciences, King’s College London, UK https://www.kcl.ac.uk/research/sharpe-group
- Dr. Vivek Thumbigere Lab, Maryland University, USA https://www.dental.umaryland.edu/periodontics/research/dr-vivek-thumbigere-math-lab/
- Prof. Shinya Murakami, Philippine Society of Periodontology https://www.psp.org.ph/index.php/speaker/prof-shinya-murakami
- Dr. Jayakumar Rangasamy, Amrita Centre for Nanosciences and Molecular Medicine, Amrita Institute of Medical Sciences and Research Centre, Amrita Vishwa Vidyapeetham University, Kochi, India. https://www.amrita.edu/faculty/dr-jayakumar-rangasamy/
- Prof. Satoru Yamada, Periodontology and endodontology, Tohoku University Graduate School of Dentistry, Sendai, Japan. https://www.dent.tohoku.ac.jp/english/research/periodontology_and_endodontology.html
- D.D. Bosshardt, Department of Periodontology and Fixed Prosthodontics, School of Dental Medicine, University of Berne, Berne, Switzerland. https://www.researchgate.net/profile/Dieter-Bosshardt
- Department of Oral Pathology and Microbiology, Subharti Dental College and Hospital, Swami Vivekanand Subharti University, Meerut, Uttar Pradesh, India. http://dental.subharti.org/oral_pathology.html
- Shruti Bhargava, Institute of Molecular Cardiovascular Research, Medical Faculty, RWTH Aachen University, 52062 Aachen, Germany. https://www.researchgate.net/profile/Shruti-Bhargava-6
- Tsuneyuki Yamamoto, Department of Developmental Biology of Hard Tissue, Hokkaido University Graduate School of Dental Medicine, Sapporo, Japan. https://www.researchgate.net/profile/Tsuneyuki-Yamamoto
References
- G. Holan, and D. J. McTigue. “Introduction to Dental Trauma: Managing Traumatic Injuries in the Primary Dentition.” Pediatric Dentistry (Sixth Edition) (Eds.: A. J. Nowak, J. R. Christensen, T. R. Mabry, J. A. Townsend, M. H. Wells), Elsevier: Philadelphia, 227 (2019).
- C. L. B. Lavelle. “Gingiva and periodontal ligament.” Applied Oral Physiology (Second Edition) (Ed.: C. L. B. Lavelle), Butterworth-Heinemann, 33 (1988).
- Zhao, Jing et al. “Stem cell contributions to cementoblast differentiation in healthy periodontal ligament and periodontitis.” Stem cells (Dayton, Ohio) vol. 39,1 (2021): 92–102. doi:10.1002/stem.3288
- Eva, Matalová et al. “Development of Tooth and Associated Structures.” Stem Cell Biology and Tissue Engineering in Dental Sciences (Eds.: A. Vishwakarma, P. Sharpe, S. Shi, M. Ramalingam), Academic Press: Boston, 335 (2015).
- Yamamoto, Tsuneyuki et al. “Histology of human cementum: Its structure, function, and development.” The Japanese dental science review vol. 52,3 (2016): 63–74. doi:10.1016/j.jdsr.2016.04.002
- Thomas, H F. “Root formation.” The International journal of developmental biology vol. 39,1 (1995): 231–7.
- Webb, P P et al. “Changing expression of intermediate filaments in fibroblasts and cementoblasts of the developing periodontal ligament of the rat molar tooth.” Journal of anatomy vol. 188 ( Pt 3),Pt 3 (1996): 529–39.
- Yamamoto, Tsuneyuki, and Shigeru Takahashi. “Hertwig’s epithelial root sheath cells do not transform into cementoblasts in rat molar cementogenesis.” Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft vol. 191,6 (2009): 547–55. doi:10.1016/j.aanat.2009.07.004
- Yamamoto, Tsuneyuki et al. “Hertwig’s epithelial root sheath cell behavior during initial acellular cementogenesis in rat molars.” Histochemistry and cell biology vol. 142,5 (2014): 489–96. doi:10.1007/s00418–014–1230–1
- Yamamoto, Tsuneyuki et al. “Hertwig’s Epithelial Root Sheath Fate during Initial Cellular Cementogenesis in Rat Molars.” Acta histochemica et cytochemica vol. 48,3 (2015): 95–101. doi:10.1267/ahc.15006
- Suhasini, Gotur Palakshappa et al. “Cementoblastoma of a primary molar: A rare pediatric occurrence.” Journal of oral and maxillofacial pathology : JOMFP vol. 24,3 (2020): 548–553. doi:10.4103/jomfp.JOMFP_307_19
- Bhargava, Shruti et al. “Development, Establishment, and Validation of a Model for the Mineralization of Periodontium Remodelling Cells: Cementoblasts.” International journal of molecular sciences vol. 24,18 13829. 7 Sep. 2023, doi:10.3390/ijms241813829
- Jin, Q-M et al. “Cementum engineering with three-dimensional polymer scaffolds.” Journal of biomedical materials research. Part A vol. 67,1 (2003): 54–60. doi:10.1002/jbm.a.10058
About the author:
DR. SURUCHI PODDAR
Content Editor The League of Extraordinary Cell Types, Sci-Illustrate Stories
Dr. Poddar received a PhD in Biomedical Engineering from Indian Institute of Technology-Banaras Hindu University (IIT-BHU), Varanasi, India. She started her career as a postdoctoral researcher in 2020 with the Nanoscience Technology Center at the University of Central Florida, Orlando where she worked on a multi-organ human-on-a-chip system. Currently she is working on solid-state nanopore technology at Wake Forest University, North Carolina. When not working, she enjoys watching movies, cooking food and exploring new places, restaurants, attractions.
About the artist:
NELLY AGHEKYAN
Contributing Artist The League of Extraordinary Cell Types, Sci-Illustrate Stories
Nelli Aghekyan did a bachelor’s and master’s in Architecture in Armenia, after studying architecture and interior design for 6 years, she concentrated on her drawing skills and continued her path in the illustration world. She works mainly on children’s book illustrations, some of her books are now being published. Currently living in Italy, she works as a full-time freelance artist, collaborating with different companies and clients.
About the animator:
DR. EMANUELE PETRETTO
Animator The League of Extraordinary Cell Types, Sci-Illustrate Stories
Dr. Petretto received his Ph.D. in Biochemistry at the University of Fribourg, Switzerland, focusing on the behavior of matter at nanoscopic scales and the stability of colloidal systems. Using molecular dynamics simulations, he explored the delicate interaction among particles, interfaces, and solvents.
Currently, he is fully pursuing another delicate interaction: the intricate interplay between art and science. Through data visualization, motion design, and games, he wants to show the wonders of the complexity surrounding us.
About the series:
The League of Extraordinary Cell types
The team at Sci-Illustrate and Endosymbiont bring to you an exciting series where we dive deep into the wondrous cell types in our body, that make our hearts tick ❤.
