Tooth Formation: Are the Hardest Tissues of Human Body Hard to Regenerate?

Abstract

With increasing life expectancy, demands for dental tissue and whole-tooth regeneration are becoming more significant. Despite great progress in medicine, including regenerative therapies, the complex structure of dental tissues introduces several challenges to the field of regenerative dentistry. Interdisciplinary efforts from cellular biologists, material scientists, and clinical odontologists are being made to establish strategies and find the solutions for dental tissue regeneration and/or whole-tooth regeneration. In recent years, many significant discoveries were done regarding signaling pathways and factors shaping calcified tissue genesis, including those of tooth. Novel biocompatible scaffolds and polymer-based drug release systems are under development and may soon result in clinically applicable biomaterials with the potential to modulate signaling cascades involved in dental tissue genesis and regeneration. Approaches for whole-tooth regeneration utilizing adult stem cells, induced pluripotent stem cells, or tooth germ cells transplantation are emerging as promising alternatives to overcome existing in vitro tissue generation hurdles. In this interdisciplinary review, most recent advances in cellular signaling guiding dental tissue genesis, novel functionalized scaffolds and drug release material, various odontogenic cell sources, and methods for tooth regeneration are discussed thus providing a multi-faceted, up-to-date, and illustrative overview on the tooth regeneration matter, alongside hints for future directions in the challenging field of regenerative dentistry.

Tissue Engineering in Oral and Maxillofacial Rehabilitation - A New Perspective

“…The regeneration of a whole tooth is considered to be the ultimate goal of regenerative dentistry. It could be performed as a hybrid strategy, where biologically created tissue compartments such as the periodontal ligament or a tooth crown would be combined with a metallic or ceramic implant or where a biologically regenerated tooth root ("bio-root") would be combined with a prosthetic crown 11 . Efforts in creating a whole tooth from only cells and 612 tissues ("bio-tooth") will be very likely in the focus in the following years 11 .…”

“…For the lost tooth regeneration capacity, revitalizing the odontogenic potency may be an interesting approach to induce tooth formation in vivo in the adult.The existence of a successional dental lamina (SDL) carrying the capacity for inducing odontogenesis is the only prerequisite for tooth replacement 11 .…”

“…In classical tissue recombination experiments embryonic tooth germs can be dissociated from native site and later re-aggregated at an ectopic sites. Tooth-like organs with mineralized tissues (dentin and enamel) could be grown after temporary ectopic grafting of these cell aggregates, e.g., into the anterior eye chamber, subcutaneously, or under the renal capsule.The final goal of these experiments was to implant the constructs into the jaws of postnatal animals to generate a whole "bio-tooth" 11 .…”

“…When combined with mesenchymal cells, adult stem cells should have an odontogenic competence and should function as a "tooth inducer" 11 . Young et al were the first to successfully regenerate tooth structure containing enamel and dentin using tooth buds from the third molars of pigs.…”

“…Tooth formation including root occurred and the teeth erupted. In addition, bone was also induced 13 .Volponi Angelova and associates used human gingival epithelial cells combined with embryonic mouse tooth mesenchyme, which yielded an entire tooth outside of an embryo 14 .Research will presumably focus on using adult stem cells from dental and non-dental sources to test recombination or co-culturing for their effects on tooth development in the future 11 .…”