Sona Khan discusses how Diet Coke impacts dental enamel and why dental professionals should be concerned about the popular soft drink.
What is dental erosion?
Dental erosion is defined as the irreversible chemical dissolution of dental hard tissues, including enamel and dentine, through a chemical process. This erosion occurs independently of bacterial or biofilm factors and is associated with an acidic oral environment, characterised by a pH level below 4.0 (Reddy et al, 2016).
Unfortunately, this damage is irreversible. The acids responsible can be extrinsic, from sources like carbonated drinks or citrus juices, or intrinsic, originating from conditions like acid reflux or eating disorders.
When exposure is short, saliva plays a crucial role in remineralising the demineralised enamel and restoring the pH to neutral (around 7.0). However, prolonged or continuous acid exposure hampers saliva’s ability to remineralise enamel, leading to irreversible loss of tooth structure.
Saliva is a key player in buffering acids and aiding in the remineralisation of dental hard tissue, but its protective effects are limited when the acid attack persists (Cardoso et al, 2019).
What’s the deal with Diet Coke?
While Diet Coke is often marketed as a healthier alternative, research by Khamverdi et al (2013) shows that it actually causes more dental erosion than regular Coca Cola. This is due to its high content of acidic flavourings like phosphoric and citric acids, which significantly lower the pH in the oral environment, leading to demineralisation.
Under short-term acid exposure, saliva can neutralise the acidity and restore pH, allowing remineralisation to occur. However, with frequent consumption, such as regular sipping of Diet Coke, this natural defence mechanism becomes overwhelmed, resulting in cumulative damage to the teeth.
The impact of regular and Diet Cola on enamel
Tooth enamel, the hardest structure in the human body, is composed of highly organised crystals arranged in 3D prisms, extending from the amelodentinal junction to the outer surface. These prisms are formed by ameloblasts, with each prism being the product of a single ameloblast. The enamel surface, far from flat, features a wavy structure with shallow grooves called perikymata.
Acidic beverages, such as cola, can disrupt this highly organised structure. Within just five minutes of exposure, the enamel crystals show significant disorder. This erosion of enamel, often accompanied by sensitivity, is closely linked to regular consumption of cola.
Studies by Lutovac et al (2017) show that those consuming soft drinks more than twice daily are four times more likely to experience enamel loss – up to 1µm per day. Left unchecked, this can lead to dentinal hypersensitivity and discomfort (Alcântara et al, 2018).
The erosive effect of carbonated drinks is due to their low pH, typically between 2.7 and 3.0, driven by the presence of phosphoric acid and, in diet cola, additional citric acid. While phosphoric acid enhances flavour and shelf life, citric acid increases acidity further, making diet cola even more erosive than regular cola. This has been confirmed by studies, including one by Khamverdi et al, which highlights the higher erosive potential of diet cola due to citric acid.
The key risk for dental health arises when beverage pH falls below the critical threshold of 4.0, causing enamel to become more soluble and prone to erosion. Understanding the pH of these beverages empowers dentists to plan effective preventative strategies as part of treatment plans.
This knowledge allows them to address dental erosion implications and guide patients in making dietary choices that avoid substances with a pH below 4 while favouring options above this threshold.
The role of citric acid in eroding enamel
Citric acid is a weak acid found in various citrus fruits such as lemons, grapefruits, tangerines and oranges. It is commonly used in beverages to enhance flavour while also acting as a natural preservative.
Research by Khamverdi et al (2013) demonstrated that while regular cola contains phosphoric acid, the increased erosive potential of diet cola can be attributed to the additional presence of citric acid. This heightened erosive effect is due to citric acid’s role as a chelator, allowing it to bind effectively to calcium ions within the hydroxyapatite structure of enamel, weakening its integrity.
Why should dental professionals be concerned?
Given that Diet Coke, which is often seen as the ‘healthier’ option, actually causes more erosion, dental professionals have every reason to be concerned. Al-Omiri et al (2006) have observed that patients with enamel wear are nine times more likely to report discontent with their teeth when compared to the control group.
Furthermore, higher levels of enamel wear have also been associated with a lower oral health related quality of life and satisfaction (Mehta et al, 2020). As a result, it is vital that the dental team can appropriately manage tooth wear, particularly dental erosion. Through such efforts, they can help to minimise its extensive impact and prevent its progression.
Over the past few decades, the consumption of these beverages has significantly increased. In 2004, Public interests reports indicated that around 37 gallons of soft drinks were produced per person annually (Jacobson, 2004).
Additionally, studies show that nearly 66% of children and 77% of adolescents consume sugary beverages daily. This rise in soft drink consumption has become a leading cause of dental erosion. Moreover, the frequent intake of these beverages is also linked to weight gain, obesity, and type 2 diabetes, particularly among adults (Lutovac et al, 2017).
Informing patients
Understanding the erosive potential of diet cola enables individuals to make informed choices regarding their consumption of beverages, as awareness is necessary for prevention. Dental professionals can play a significant role by conducting dietary analysis, enabling them to promote preventive education and collaborate with patients in making informed choices. This approach empowers individuals to take control over their oral health.
By assisting patients in selecting beverages with a pH above 4 and advising them to gradually eliminate acid consumption, we can empower patients to make impactful dietary adjustments to help maintain the integrity of enamel. It is then essential that individuals use this information, consider making the required dietary changes and seek dental advice to protect their oral health.
Further research into dental erosion and its impact on enamel will help to discover more effective preventive measures. The erosive potential of diet cola is a topic of concern, and it serves as a reminder that an individual’s dietary choices can impact their oral health with significant consequences.
So, if you are a Diet Coke lover, it might be time to rethink your drink of choice. Your teeth will thank you!
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