Clinical definition of dental decay
Dental decay is characterised by the loss of mineral ions from the tooth caused by the presence of bacteria in plaque and their acidic by-products.
The basic carious process can also be called an acid attack. Bacterial plaque builds up on the tooth surface. When sugars enter the mouth they are absorbed by this layer. Inside the bacterial cells the sugars are broken down (or metabolised) and acid is produced.
Why we need to address dental decay
Dental decay, also known as tooth decay or dental caries, is a widespread condition in the Western world and a particular problem in Scotland.
The National Dental Inspection Programme’s (NDIP) research in 2008 highlighted that 42 per cent of Scottish children have signs of dental decay and this figure is even higher in areas of deprivation.
For the first time in 2013, all P7 children in all communities reached the national target of 60% of children having no obvious decay experience, with the largest improvements seen in areas in the most deprived quintile.
From 2013 to 2019, the percentage of P7 children from the most deprived quintile with no obvious decay experience increased from 60.7 to 69.5. From 2014 to 2020, the percentage of P1 children from the most deprived quintile with no obvious decay experience increased from 52.9 to 58.1.
Significant improvements have occurred in the oral health of Scottish Children since the start of NDIP in the early 2000s. It is estimated that the latest inspection data suggests a plateau, and oral health inequalities persist. This should be the main focus of oral health improvement activities as the Childsmile Programme adapts and re-mobilises following the pandemic across all NHS boards.
Progression of caries
Caries is a progressive disease – it starts with a healthy tooth, and progresses through small lesions to large cavities. It is possible to interrupt the process and to repair damage caused by decay. However, other than in the earliest lesions, it is not possible to regain tooth tissue, once it has been lost.
The earliest manifestation of the disease is demineralisation of the enamel. This stage, as mentioned before, can be reversible with meticulous cleaning, change in diet and fluoride treatment.
If the demineralisation phase is not reversed it will progress to enamel decay. The enamel layer is a very hard layer of the tooth and is designed to protect the softer, inner dentine layer. This stage can be interrupted either by fluoride treatment, fissure sealants or tiny, shallow fillings. If the process is not stopped, the decay will progress through the enamel layer, as an established decay process, until it reaches the dentine.
Once it has reached the dentine, the enamel is undermined and the outer enamel layer collapses forming a cavity. The dentine is destroyed at a greater rate because dentine is not calcified. As the dentine is lost in the decay process, the cavity deepens. At this stage the tooth can be very painful on eating and the caries rapidly progresses into the underlying pulp (which contains the nerves and vessels). If a dentist or therapist intervenes at this stage, the decayed enamel and dentine must be excavated or drilled out and a filling placed.
Once the disease process reaches the pulp, an abscess may form. This can give the child a continuous toothache, as well as intermittent pain on eating. At this stage the tooth would either need a root treatment or an extraction (Mount and Hume 2005; Levine and Stillman-Lowe 2014, 7th edition).