This will depend on at what stage the decay has been detected. If early on, reducing sugary foods and drinks and brushing regularly using a fluoride tooth paste may prevent the decay from developing.
If decay has been spotted later on and you have a hole in your tooth, further treatment may be required, such as a filling, crown; root canal treatment, or the removal of the tooth. The gap can then be either restored with a bridge, denture or dental implant. Our dentist in London would do a thorough assessment of your teeth to see which treatment would be best to help you.