The impact of genes on disease risk
Deborah Lyle considers the links between genetics and oral diseases.
It is well known that oral diseases cause pain and discomfort. As well as a loss of confidence and self-esteem and can seriously disrupt a person’s life.
Tooth decay or missing teeth can lead to social isolation. It has been reported by Public Health England (2017) that visibly decayed teeth or bad breath can disadvantage an individual. Particularly when it comes to gaining employment or being promoted at work.
In addition, there is growing evidence to link oral diseases with systemic conditions. For example: cardiovascular disease, bacterial pneumonia, diabetes mellitus and low birth weight (Xiaojing et al, 2000; Babu and Gomes, 2011).
These are the reasons dental professionals work tirelessly to help patients understand the importance of a good oral health and promote preventive strategies.
However, at least 3.58 billion people worldwide are affected by oral disease and, caries in the permanent teeth remain the most prevalent (GBD, 2017).
Dental decay susceptibility
A number of reasons have been suggested as to why individuals develop caries.
It is largely attributed to poor oral hygiene. Also, factors such as excessive consumption of sugar, snacking between meals and use of tobacco.
Nevertheless, in spite of diligently following an effective oral health routine with exposure to fluoride and good dietary habits, some people still develop dental decay; while others that are not so conscientious, remain caries free.
It has been suggested that some individuals have a kind of natural immunity to caries. Others have what is popularly known as ‘weak teeth’, which are less resistant to decay.
In the past these variances have been attributed to factors such as excessive milk consumption, infections and repetitive or prolonged use of antibiotics in childhood.
However, recent studies indicate that a genetic variation involved with the formation of tooth enamel could make this hard tissue more or less susceptible to demineralisation under acidic conditions, which is relevant to the development of dental caries (Vieira et al, 2015; Shimizu et al, 2012).
There is also substantial evidence that genetic factors are associated with an increased risk of developing periodontal disease (Tettamanti et al, 2017).
It has been suggested that the heritability of periodontitis seems to be biological rather than behavioural (Michalowia, 2000). Recent investigations into factors that may increase susceptibility to periodontitis have focused more strongly on genes.
Moreover, a recent systematic review of 13 studies with more than 71,500 participants revealed that seven interleukins namely IL-1A, IL-1B, IL-4, IL-6, IL-8, IL-10, and IL-18 (particularly important in stimulating immune responses, such as inflammation); three fcγreceptors, FCGR2A, FCGR3A, FCGR3B, which are involved in the stimulation of antibodies and regulation of immune responses; and five inflammatory mediators COX-2, MMP-2, MMP-3, MMP-8, MMP-8 and MMP-9, were significantly associated with risk of development of periodontal disease (da Silva et al, 2017).
This article merely scratches the surface. It has been established that some people may have a strong genetic predisposition to certain oral diseases. This would indicate that the detection of such genes could enable clinicians to better identify high-risk individuals. Targeted prevention and treatment could be implemented.
However, at present, it has been acknowledged that further studies are required to discover how the thousands of genes in the human genome and the large number of bacteria within the oral cavity interact within the environment to alter disease risk (Quazi et al, 2017).
Consequently, the fundamental messages and promotion of good oral health along with the reduction of sugary foods and drinks, alcohol and tobacco, exposure to fluoride and regular dental attendance remain significantly important.
Maintaining optimal oral hygiene should be the first and foremost concern for patients of all ages. This is regardless of whether a patient has ‘strong’ or ‘weak’ teeth, or an increased risk of periodontal disease.
The possibility of new diagnostic markers and gene-specific preventive strategies is on the horizon. It is important to stay abreast of the investigations into the genetic components. Especially where they may play a role in the risk, onset and progression of oral diseases.
Equally, clinical studies help dental professionals to make informed decisions about dental care and the recommendations they make to their patients.
This ultimately provides the best possible oral health outcomes.
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