Everyone has genes, which have been passed down from their great-great-great-great grandfather and beyond. Genes, made of DNA, contribute to the unique physical features of each individual, and determine the very way a body functions [1]. Genes influence valued traits such as eye color, body composition, height, etc, but also unwanted traits like diseases [2]. Hence, in the 1960s-70s, Theodore Friedmann and Richard Roblin began their research in gene therapy and engineering to ameliorate genetic diseases [2]. Today, genetic engineering, a process that uses laboratory-based technologies to alter the DNA makeup of an organism, assists in saving lives and serves as a mollifier to health issues. One area where genetic engineering has become increasingly popular in is oral health and dentistry due to recent advancements in diagnostics and preventative innovations [3]. This paves the path for a possible future where expensive surgeries and certain medicines can be avoided entirely [4].
Genetic makeup is a significant factor in determining one’s vulnerability to being infected by certain oral diseases [5]. By understanding conditions which are likely to occur in patients with certain genetics, healthcare and dental hygienists are given a key to assist in the prevention of problems through early detection, and resources to facilitate the process.
Cavities, or simply put, tooth decay, are permanent holes in teeth caused by bacteria from the mouth feeding of sugars and starches. These bacteria produce sticky acids called plaque that wear down tooth enamel and damage the gums [6]. People often associate tooth decay with poor oral hygiene and environmental influences, which to a certain degree, is true [5]. For instance, through the practice of brushing teeth twice a day with fluoride, or limiting the amount of sugary foods consumed, one can have a greater chance of protecting their teeth from an overproduction of harmful acidic byproducts made by the bacteria in the mouth [6]. Fluoride can assist in the repair of enamel and minerals, helping prevent tooth decay early on. However, as stated previously, it has been concluded that genes play a critical role in both how susceptible someone is to oral problems, as well as the aesthetics of their teeth and jaw [5]. Diseases like dental caries become a more severe issue for those who have abnormal tooth structure or weak tissue makeup, leading researchers to seek solutions in genetic engineering.
Gene therapy is a type of genetic engineering that can cure genetic dental diseases by targeting the genes responsible for heredity disorders. For example, gene therapy can help correct defects in the KLK4 gene that causes amelogenesis imperfecta, a genetic disorder causing defective tooth enamel formation [3]. Similarly, suicide gene therapy, where a gene encoding a toxin or enzyme is introduced to diseased cells, is used to target oral cancers. In this method, genes like HSV-TK, which convert inactive prodrugs into cytotoxic substances, destroy the DNA of cancer cells. This method is effective due to its format—a precise injection into the tumor or surgical area—as well as the way it performs the bystander effect, killing nearby cancer cells without causing harm to healthy tissue.
Another method of genetic engineering in dental care is regeneration. Regeneration is primarily used to grow the jaw/alveolar bone, since teeth are unable to naturally repair themselves due to their enamel and dentin makeup. Ex vivo or in vivo techniques are often used for patients who suffer from irregular jawbone growth. These include synthetic jawbone transplants or the injection of genetic material to instruct cells to build bone. Dental pulp has a natural ability to regenerate dentin and tooth injuries, but it can be enhanced through gene therapy and stem-cell applications [4].
Although genetic engineering in dentistry indisputably offers hope for beneficial outcomes in dental care and other fields, it is essential to understand its limitations. For instance, ONYX-015, an engineered adenovirus used for the treatment of head and neck cancers, showed limited efficacy in destroying p-53 deficient cancer cells when administered alone [4]. While it did cause cell death within tumors, the effect of it could not be connected in any way to the patient’s p-53 genetic mutations, as was expected, implying that a more sufficient design would be needed [4]. Additionally, despite the interests in using gene therapy, bioengineering, and cell sciences for improving dentistry, it is still not practical, as there are a lack of studies on gum disease treatment and repairment. Therefore, future research is still needed to make these approaches more common and reliable therapeutic treatments.
Today, various forms of gene therapy are continuing to improve as researchers explore more ways to integrate it into oral healthcare whilst maintaining ethicality [5]. For instance, not only is suicide gene therapy being practiced in killing cancer cells, researchers are attempting to expand its effectiveness in treating orofacial/chronic oral pain, dry mouth, and even jawbone regeneration [4]. Nanorobotics also holds great potential, as nanorobots could offer even more accurate and efficient solutions to dental problems, as they are primarily used for plaque removal and bacteria destruction as of today [3].
Ultimately, bioengineering in oral health provides great potential to expand beyond just traditional treatments, offering a hopeful future of oral health.