• Kayla Hui

Teeth Regeneration

The American College of Prosthodontists estimates that 178 million people in America have lost at least one tooth, with 40 million people having lost all their teeth. Tooth loss is extremely common due to the prevalence of gum disease or decay due to injuries or age. Edentulism, the total loss of all teeth, impacts the especially vulnerable populations such as the aging or those in poverty.

Losing a tooth often has several psychological or emotional impacts accompanied by this. A study showed that 58% of those with edentulism have experienced difficulty accepting their tooth loss, while 37% have felt unprepared. Those with difficulty accepting their tooth loss, have had a greater loss of self-esteem due to the loss. In these cases, dentures are often utilized as they are most often covered by insurance providers. There is also the option of implants which is more costly and not usually covered. However, both of these options generally cover the aesthetic and core functions of a tooth. Teeth regeneration is likely to be a costly procedure and likely not feasible for many of those with complete teeth loss. But it presents a solution to a multitude of problems that are caused by implants, such as swelling, infection, and pain.

Teeth regeneration is the use of stem cell-based therapies for the regeneration of natural teeth. There have been multiple animal studies on teeth regeneration that appear promising, however, more research is still needed before human trials can occur. In some innovations of tooth regeneration, it is proposed to use dental stem cells, a minor population of mesenchymal stem cells which only exist in specialized dental tissues. These specialized tissues include structures such as dental pulp, periodontium, apical papilla, dental follicle, and others. Dental stem cells have a differentiation potential, the ability of stem cells to mature to become a different embryonic cell, making them more promising for tooth repair.

For example, regenerating dental pulp tissue, a soft connective tissue that occupies the central most cavity of the tooth, has been a focus of researchers and clinical trials to replace conventional treatments. While pulp capping and root canal therapy can maintain the structure and function of the teeth, they are unable to sustain the vitality of the dental pulp. This causes complications such as the tooth being unable to form reparative dentin, creating problems during chewing, or causing discoloration.

The proposed solution for the regeneration of dental pulp is the usage of stem cells of human exfoliated deciduous teeth (SHED) and dental pulp stem cells (DPSC). DCSPs and SHEDs differ from each other, with SHEDs having a higher rate of proliferation than DCSPs and are reported to be able to double the population of a cell. SHED is also important in dental pulp tissue engineering, which is where the dental pulp is replaced with stem cells. DPSCs can differentiate into osteoblasts and have been used for dental pulp regeneration.

In an animal study, both DPSCs and SHEDs were seeded in biodegradable scaffolds, temporary “templates” used to engineer living tissues due to their properties similar to the extracellular matrix, to form vascularized pulp/dentin-like tissue. This tissue was then placed in an emptied human root canal which was transplanted into immunodeficient mice.

In an animal study with larger animals, reparative dentin was formed after autologous, meaning from the same individual, transplantation of DPSCs pellets was stimulated by bone morphogenetic protein 2 onto the amputated pulp of dog teeth. These animal studies have shown the great promise of DSPCs application in endodontic treatment for humans. Many innovations are being used to optimize the application of DPSCs in clinics for future studies.

Whole tooth regeneration is still far off in the future due to its complexity.

Currently, the treatment for the replacement of teeth are implants that screw a metal rod in the bone and caps it with a plastic or ceramic crown. As previously mentioned implants have their imperfections, especially with the surgery having the potential of infection, damaging surrounding structures, nerve damage, or sinus problems. The stem cells presented and many other types sourced from other parts of the body, such as periodontal ligament stem cells or root apical papilla stem cells, show promise in treating injuries and damage in the future.

Overall stem cells from dental tissues could be a major advancement in both tooth and periodontal tooth regeneration, due to their ability to generate osteogenic, adipogenic, and chondrogenic variations of stem cells. Teeth regeneration and dental stem cells also show potential for the future of translational medicine, a growing branch of biomedical research that aims to expedite the formation of new tools by using a “bench to bedside” approach. Like most innovations, teeth regeneration still has a far way to go and proper quality control and a better understanding of the underlying mechanisms for regulating dental stem cells are still needed.