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How to prevent tooth decay

The science behind tooth decay

Dental caries, commonly referred to as tooth decay, manifests as a gradual process and

progressive disease affecting the dental hard tissues, resulting in the breakdown of tooth

structure and the potential for pain and infection within the oral cavity. Understanding the

mechanisms behind tooth decay is crucial for adopting effective preventative measures, to

stop or reverse the carious process and prevent cavity formation.

Several factors contribute to dental caries, including bacteria, time, fermentable

carbohydrates, and a susceptible tooth surface. In the absence of regular toothbrushing, a

plaque biofilm is allowed to form on the tooth surface—a sticky, colourless film that serves

as a breeding ground for bacteria such as Streptococcus mutans and Lactobacillus species.

Once these bacterial species encounter fermentable carbohydrates and sugars from our

diet, they begin to metabolise them, producing acids as a by-product. These acids contribute to an acidic environment in the mouth. When enamel, the outermost layer of tooth structure, is exposed to an acidic pH below 5.5, its mineral structure weakens, initiating the dissociation of hydroxyapatite crystals. Frequent acid attacks from dietary sugars result in a net mineral loss in teeth, leading to cavity formation, dental pain, and potential infections.

The initial stage of decay involves the demineralisation of enamel. At this point, the damage

can be reversible with good oral hygiene practices and through remineralising agents. Saliva

has the capacity to remineralise initial carious lesions, and fluoride application through

fluoridated toothpaste can also aid in reversing the initial stages of dental caries. However,

if left untreated and allowed to progress, the decay can develop further into the tooth

structure reaching the softer dentine beneath enamel. Dentin decay occurs more rapidly

than enamel and can contribute to increased sensitivity and discomfort.

As the decay advances, it may reach the dental pulp, which is the nerve of the tooth.

Infection of the pulp can trigger severe pain and may necessitate root canal treatment in

attempt to save the tooth. Persistent infections can lead to abscess formation—a pocket of

pus causing swelling, pain, and systemic health issues, should the infection spread

throughout the body.

Tooth decay can be preventing through regular brushing with a fluoride toothpaste. The

consistent disturbance to the plaque biofilm formation through brushing it away will not

allow the caries process to continue, and hence prevent cavity formation. The fluoride

aspect will help to strengthen the enamel and remineralise any mineral loss found in early

lesions; this can stop and even reverse the carious process, thus preventing dental decay

A healthy diet with limited consumption of sugary foods and drinks can significantly reduce

the risk of tooth decay; with less sugars in the oral environment there is a lower rate of

bacterial metabolization to create the acids which contribute to the decay process.

Regular dental check up appointments enable early detection and intervention of any initial

lesions, preventing the progression of decay before reaching an irreversible status.

Tooth decay is a preventable yet prevalent oral health issue. Instigated by the action of oral

bacteria metabolising sugars in the mouth, our natural tooth structure can be destructed

and decayed if the plaque biofilm is not controlled. By understanding the causes and

progression of tooth decay, individuals can adopt proactive measures to maintain good oral

hygiene, preserve enamel, and safeguard their smiles for a lifetime. Regular dental check-

ups and a commitment to a healthy lifestyle play pivotal roles in preventing the onset and

progression of tooth decay.

Written by Isha Parmar


(Banerjee & Watson, 2015): Banerjee, A. and Watson, T.F. (2015) Pickard’s Guide to

Minimally Invasive Operative Dentistry, King’s College London.

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