Current Approaches and Challenges in Making a Bio-Tooth

Abstract

Tooth loss adversely affects not only mouth functions but also the esthetics of one's face. To repair these defects, current treatment methods mainly depend on nonbiological materials or artificial implants that also can, sometimes, reduce the quality of life because of their limited physiological function, or elicit an immunological rejection. Theoretically, a biological tooth (bio-tooth) that is made from the patient's own cells and grows in its intended location should be the best choice for treating tooth loss, although such bioengineered teeth have been nothing more than a dream for many centuries. Recently, significant advances in the fields of tissue engineering, stem cell biology, developmental biology, molecular genetics, and bionics have brought us close to the realization of a bio-tooth. However, issues involving in the reconstruction of a bio-tooth regarding the shape determination, size control, availability of dental epithelium, directional growth and eruption, and graft rejection in the jaws remain to be resolved. Here, this review outlines the current approaches toward the tooth regeneration, and focuses on several key challenges that must be met in the making of a bio-tooth.

Whole-organ engineering with natural extracellular materials

“…Bioengineering strategies have targeted tooth regeneration using various combinations of scaffolds, growth factors and cells [81][82][83][84]. Approaches using tissue recombinations, and pelleting cells in a scaffold-free environment, are also popular strategies for whole-tooth engineering [85,86]. In addition, groups have investigated the location of the implantation site for engineered implants as a morphogenetic means of developmental signaling.…”

“…The adult human gingival cells contributed to the formation of ameloblast-like cells and rests of Malassez [134]. Furthermore, chimeric teeth, generated from autologous dental mesenchyme combined with xenogenic dental epithelium, may eventually be used as a clinically relevant alternative approach [86,90].…”

Dental Pulp Stem Cell Niche

“…Thirdly, the acidic side-products of some scaffolds such as polyglycolic acid (PGA), poly(lactic-co-glycolic acid) (PLGA) and PLLA, may exert an adverse effect on the proliferation of stem cells in vivo. Finally, the nutrient delivery and metabolic waste removal inside the central scaffolds are often limited following the dentinogenesis, which may negatively affect the growth and differentiation of DPSCs [61].…”

A Journey from Dental Pulp Stem Cells to a Bio-tooth

“…Using the principle of epithelialmesenchymal interactions to guide the tooth regeneration has become a common strategy in dental tissue engineering. Many studies have demonstrated that the bio-tooth can be reconstructed by dental cells recombined with or without scaffolds, by pre/post-natal dental cells, and even by nondental cells [9,29,66,67,70,[82][83][84][85][86][87]. Nakao et al have demonstrated that bioengineered incisor tooth germs can be reconstituted using completely dissociated dental epithelial and mesenchymal cells in a three-dimensional collagen gel [88].…”