By Brooke Blum
As the daughter of a dentist, I never really thought about the dangerous effects that dentistry can have on individuals. Therefore, I decided to investigate the range of materials and treatments that my dad’s patients encounter daily at his office as well as those that he is exposed to. Due to their genotoxicity and ability to produce cell mutations, a variety of chemicals and radiation in dental offices are dangerous to all those who enter their doors.
Numerous studies have been conducted to understand the negative consequences and health hazards of dental work. Some of these materials have proven to be potentially dangerous and damage DNA, which can result in chronic degenerative diseases like cancer. Despite the modest risk of cancer, these dangers nonetheless exist.
Many harmful compounds, including metals, adhesives, and composites, are placed in a patient’s mouth for extended periods of time, which can cause damage to the patient. For instance, mercury is present in amalgam fillings used to fill a tooth’s cavities, holes, or gaps. Mercury can destroy DNA when it enters the body due to its affinity for sulfhydryl groups and can possibly be released and dispersed into the oral cavity. Components of dental fillings can be released into the mouth by corrosion, salivary acidity, chewing/grinding, and brushing.
A study showed an increase in cellular damage from contact with amalgam fillings. Participants with amalgam and composite fillings had a buccal cell sample obtained close to their filling. When a micronucleus assay was conducted in buccal epithelial cells, the subjects with amalgam fillings exhibited the greatest degree of genotoxic changes in their buccal cells, while patients without fillings showed the least amount of genotoxic changes in their buccal cells. In comparison to the group without fillings, the participants with amalgam and composite fillings had a significantly higher number of micronuclei.
Orthodontic braces, another standard dental procedure, are often worn for one to three years and are composed of titanium, stainless steel, gold, and chrome. Nickel, chromium, and cobalt metallic ions may be released into the oral environment as part of this procedure and direct contact may damage DNA oxidatively or prevent DNA replication (Gangadharan et al., 2013). The micronuclei of individuals that were assessed and recorded during various stages of orthodontic treatment revealed that fixed orthodontic appliances induce increased micronuclei frequency, especially in the first weeks of treatment.
In addition, the composites utilized in gluing braces also release a variety of monomers. Plaque, acids, and inflated levels of oxygen in saliva, leading to DNA fragmentation in the buccal mucosa, can lead to this corrosion. These free monomers can have toxic effects on adjacent oral tissue. The residual monomers are ingested or absorbed into the digestive system through the saliva from the mucosa of the mouth or pharynx. Using human peripheral lymphocytes in the presence or absence of metabolic activation, the genotoxicity of three glass ionomer cements used in dentistry – produced by American (Vitrebond), Japanese (Fuji I), and European (Ketac Cem) companies – was investigated. Vitrebond caused genotoxicity directly. In vitro, eluates produced from commercially available resin-modified glass ionomer cements increased the rates of sister chromatid exchanges and chromosomal abnormalities in peripheral blood cells, resulting in significant genotoxic consequences.
Another substance used in many dental practices is nitrous oxide, also known as “laughing gas,” an inhaled anesthetic. Blood samples were taken from males and females who had been occupationally exposed to anesthetics for at least five years with nitrous oxide. The control group consisted of healthcare workers who had not been exposed and were matched based on age, gender, smoking behavior, and length of employment. It was found that occupational exposure to nitrous oxide is directly associated with increased DNA damage and the level of exposure plays a critical role.
X-rays are used in dentistry to detect diseases that can’t be found by a dental examination. Ionizing radiation is released by X-rays and has been found to induce micronuclei, single and double DNA strand breaks, and apoptosis (cell death). X-ray radiation emitted during panoramic dental radiography affects cells and increases the frequency of chromosomal damage and nuclear alterations . A procedure and analysis done with the epithelial gingival cells from 40 individuals found that following exposure, the frequency of micronuclei was significantly higher after exposure, and also the frequencies of nuclear alterations indicative of apoptosis (programmed cell death). This indicates that the radiation emitted from panoramic dental radiography has a genotoxic effect.
Additionally, some teeth-whitening chemicals can lead to the formation of micronuclei. Hydrogen peroxide, a common ingredient in whitening products, is an oxidizing agent in eukaryotic cells. Oxidative stress induces genetic damage and mutations in living cells, which are associated with the formation of micronuclei.
Toothpastes containing whitening products were also found to be genotoxic using human gingival cells in vitro. For example, in human oral mucosa cells exposed to bleaching treatment, the micronucleus frequency increased. An in vivo evaluation was done with one group using a whitening dental product containing 10% hydrogen peroxide concentration, while the other group did not. Samples of saliva and oral epithelial cells were extracted from each group at various times. The Buccal Micronucleus Cytome assay (BMCyt) was used to survey the cells. This assay tests for DNA damage, micronuclei, chromosomal instability, cell death, and the regenerative potential of human buccal mucosal tissue. Individuals exposed to the 10% hydrogen peroxide product exhibited more nuclear abnormalities in oral epithelial cells and 8-OHdG in saliva (8-Hydroxyguanosine), a marker of oxidative and nuclear DNA damage.
Knowledge is power. Being aware of and knowing about these risks enables dentists, dental staff members, and patients to take precautions against these hazards. Patients can discuss with their dentists their potential concerns and the ways in which they can be addressed. For example, while gold dental restorations are not aesthetic, gold is a noble metal, and a much safer alternative to dental fillings containing amalgam or composites. There are also aesthetic filing alternatives which can be considered, such as porcelain. Instead of using metal brackets in orthodontic treatment, newer ceramic brackets can be utilized. Additionally, patients can limit the usage of whitening products and laughing gas. When having x-rays, patients can also wear protective lead aprons with thyroid collars to minimize exposure while the dentist waits outside.