Adults cannot naturally grow new teeth. Humans are limited to two sets of teeth during their lifetime. While natural regrowth isn’t possible, scientific research is exploring possibilities for tooth regeneration. This article explores the natural process of tooth replacement, the biological reasons adults do not regrow teeth, current solutions for tooth loss, and emerging research.
The Natural Process of Tooth Replacement
Human tooth development begins before birth. Primary, or deciduous, teeth start forming between the sixth and eighth week of prenatal development, with permanent teeth beginning around the twentieth week. Children have 20 primary teeth, emerging around six to twelve months of age and all present by three years.
These primary teeth act as placeholders, guiding alignment for the permanent teeth that follow. Around age six, children begin to lose primary teeth, making way for permanent teeth. This process continues into the teenage years, as primary teeth are shed and replaced. By approximately 21 years of age, an average person has 32 permanent teeth, including wisdom teeth.
Why Adults Don’t Naturally Regrow Teeth
The dental lamina, a band of epithelial tissue, is the initial evidence of tooth development in the embryo. This tissue helps form tooth buds for both primary and permanent teeth. During development, the dental lamina disintegrates, separating the developing tooth from the oral cavity epithelium.
Once adult teeth are formed, the cells that create enamel, called ameloblasts, are discarded by the body, meaning new complete teeth cannot be made without them. Dental stem cells, important for tooth development and repair, become dormant in adulthood, significantly limiting the body’s natural regenerative capacity for teeth. This contrasts with bones, which possess active stem cells and robust blood flow, enabling them to heal and remodel throughout life.
Current Solutions for Tooth Loss
Dental interventions address tooth loss. Dental implants are a solution, involving a titanium screw surgically placed into the jawbone as a replacement tooth root. A prosthetic tooth is then fixed on top, offering a natural look and function that can last for many years.
Dental bridges provide another option, bridging the gap created by one or more missing teeth. These consist of crowns placed on adjacent natural teeth, with artificial teeth suspended between them. For more extensive tooth loss, dentures, which can be full or partial, offer a removable solution for replacing multiple teeth. These solutions restore chewing function and aesthetics, but are artificial replacements, not biological regeneration.
Emerging Research on Tooth Regeneration
Research is advancing tooth regeneration. Stem cell therapy uses stem cells to grow new tooth structures. Scientists are exploring methods to coax these cells into forming the specific cell types needed for enamel, dentin, and pulp. This research includes creating tooth germs in a laboratory setting for transplantation.
Bioengineered teeth represent another promising avenue, focusing on creating living tooth tissues with properties similar to natural teeth. This involves seeding dental stem cells onto scaffolds that mimic the natural tooth structure, leading to functional replacement teeth. Researchers have successfully bioengineered human-like teeth in pigs, demonstrating the successful formation of tooth-like tissues. Additionally, gene editing techniques, such as CRISPR, are being investigated to activate dormant genes responsible for tooth development or to stimulate the growth of a “third dentition.” These approaches are experimental, but they offer hope for future biological solutions to tooth loss.