In the world of superhero powers few have as many real-world applications as the power of re-genesis. Take Marvel Comic's Wolverine character for example. Not only does he have powerful physical abilities, but he also has what's referred to as the "healing factor"—in other words, he can regenerate damaged tissues.
In the world of dentistry, bone loss is a perpetual and permanent complication of poor dental health. Recently, however, researchers have successfully made breakthroughs that might give patients a little of Wolverine’s powers for their own: dental stem cells.
Stem cells were the "hot-button" issue of the early 2000s, provoking excitement for their potential to re-grow nearly any tissue from a patient's own cells, and controversy over their source, which at the time was non-viable human embryos left over from in vitro fertilization. Searching for an alternate method, researchers devised new techniques that induced adult cells back into pluripotency, enabling them to differentiate into many cell types.
Since stem cells faded from the media's spotlight, a number of promising studies realized these possibilities, including re-growing large portions of a patient's jawbone. Many of these applications are in the field of dentistry, and range from simple dentin repair to regrowth of entire craniofacial structures. Take a look at some of the emerging treatments that dentists might offer in the future.
Regenerating Peripheral Nerves
Sometimes described as the biggest complication of dental surgery, damage to the nervous tissue of the mouth can cause patients a mixture of pain, numbness and discomfort that has the potential to last for years. Even routine procedures like root canals and extractions carry this risk, and while dentists are usually not held liable for this outcome, doing no harm to patients is a core value for all clinicians.
Many current treatments require autologous nerve grafts, in which nerve tissue is harvested from a location on the patient and transplanted to the affected area. This procedure is expensive, difficult and essentially exchanges one area of nerve damage for another. In October 2015, researchers in Japan announced that they had engineered a treatment for peripheral nerve damage using mobilized dental pulp stem cells (MDPSCs). These cells were easily obtained from extracted teeth, and were found to stimulate blood vessel growth and regeneration of nervous tissue when implanted at the site of damage.
Further study revealed that the MDPSCs secreted angiogenic and neurotrophic growth factors that could potentially be activated with stimulating agents to increase the efficacy of the treatment, or isolated to provide an injectable prophylaxis during dental surgery.
Often, a patient presents with such a severely compromised endodontic structure that there is no option but to extract the tooth and place an implant. Dental implants necessitate additional surgical intervention in approximately 12.4 percent of patients, whereas endodontic treatments only experience a 1.3 percent failure rate. A Harvard-led team has developed a new technique to increase the range of teeth appropriate for endodontic treatment in the interest of minimizing the chance of complications.
The researchers used low-power laser treatments to trigger human dental stem cells to form dentin, and through the use of animal models, were able to precisely describe the biochemical process. Low-intensity laser light has been of clinical interest since the 1960s, but results have been inconsistent without an understanding of the mechanism behind it. This study marks the first time the process of a cellular laser therapy has been discovered in a dental context.
Regrowing Manibular Bone
Bone loss is the biggest obstacle in dental implantology, and treating patients with severe orofacial injuries often carries a mixed prognosis. Autologous bone grafts can be successful, but require harvesting bone from the patient, and allografts most often come in a spongy paste. This paste is unsuitable for larger reconstructive work that must be rigid at the outset, as in the case of a 45-year-old female patient missing seven front teeth and 75 percent of the bone that once supported them.
Researchers at the University of Michigan School of Dentistry inoculated a b-tricalcium phosphate scaffold with bone marrow-derived multipotent stem cells, and implanted the fixture in a procedure that required only local anesthesia. In just four months, nearly all of the patient's missing mandibular bone had regenerated, allowing for the placement of implants. The patient left her final appointment with a perfect smile she hadn’t seen in five years.
Stem cell technology continues to offer the dental field new approaches to patient care, more efficacious treatment and minimally-invasive methods. Treatments derived from a patient's own cells will not provoke rejection and therefore maximize the potential of success, especially in those who are immuno-compromised or sensitive to foreign materials. The "hot button" of 2003 has become a big, blinking green one. Are you ready to push it?
Yamamoto, T.; Osako, Y.; Ito, M.; Murakami, M.; Hayashi, Y.; Horibe, H.; Iohara, K.; Takeuchi, N.; Okui, N.; Hirata, H.; Nakayama, H.; Kurita, K.; Nakashima, M. Trophic Effects of Dental Pulp Stem Cells on Schwann Cells in Peripheral Nerve Regeneration. Cell Transplant. Appeared or available on-line: April 22, 2015. http://www.eurekalert.org/pub_releases/2015-07/ctco-dpc070615.php
Narang, S., & Sehgal, N. (n.d.). Stem cells: A potential regenerative future in dentistry. Indian J Hum Genet Indian Journal of Human Genetics, 150-150. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3491285/
American Association of Endodontists. (n.d.). Retrieved November 17, 2015, from http://www.aae.org/about-aae/news-room/press-releases/new-research-shows-dental-implants-require-significantly-more-follow-up-treatment-than-root-canals.aspx
Researchers use light to coax stem cells to repair teeth. (n.d.). Retrieved November 17, 2015, from http://www.seas.harvard.edu/news/2014/05/researchers-use-light-to-coax-stem-cells-to-repair-teeth
Rajan, A., Eubanks, E., Edwards, S., Aronovich, S., Travan, S., Rudek, I., . . . Kaigler, D. (2014). Optimized Cell Survival and Seeding Efficiency for Craniofacial Tissue Engineering Using Clinical Stem Cell Therapy. Stem Cells Translational Medicine, 1495-1503.