Tooth decay

Early demineralisation confined to enamel, where the surface is still intact, can be arrested and partly remineralised with fluoride, reduced sugar frequency and better cleaning, which is why some areas are monitored, not drilled. Once the surface has broken down and a cavity has formed in dentine, that tissue cannot be restored biologically and needs removing and filling. The distinction is a clinical judgment from examination and radiographs, and it is entirely reasonable to ask which category yours is in.

Brushing cleans the surfaces a brush can reach, but most decay starts between teeth and in deep grooves where bristles do not go. Beyond cleaning, the biggest drivers are how often sugar is consumed and whether you have adequate saliva. Dry mouth from medication is a very common and under-recognized cause of decay in people with good brushing habits. Existing fillings, exposed roots and deep fissures also add risk independently of technique.

Not necessarily. Sugar-free products avoid the bacterial acid pathway, but many are themselves acidic: sugar-free fizzy drinks, sparkling water with citrus flavouring and some sugar-free sweets can erode enamel directly through their own acidity. That is a different process from decay but it also removes mineral. Products sweetened with xylitol are generally regarded more favorably. The useful question is whether something is both sugar-free and non-acidic.

The interval should be set by your individual decay risk instead of by a fixed schedule. Someone with active decay, many restorations, dry mouth or a high-sugar diet needs more frequent radiographic review than someone with a stable, low-risk mouth. The purpose is to find decay between teeth while it is still small enough to treat conservatively. If you are unsure why an interval has been chosen, asking what risk category you are in is a fair question.

It usually means early demineralisation that has not yet cavitated, where the clinician judges that arresting it with fluoride, diet change and cleaning is preferable to drilling. That is good practice instead of delay, because every restoration begins a cycle of eventual replacement. What matters is that it is genuinely monitored, recorded, reviewed and reassessed radiographically, not forgotten. Ask when it will be checked again and what would change the plan.

Yes, and it is one of the main reasons fillings are replaced. The junction between a restoration and the tooth is the vulnerable point, and decay starting there progresses under an opaque material where it is neither visible nor painful until it is well advanced. This is why radiographic review matters more on a heavily restored mouth, not less, and why cleaning right at the margins is worth the effort.

Very much so, and it is one of the most significant risk factors there is. Saliva buffers acid, clears food debris and carries the minerals that repair early damage: remove it and the recovery half of the decay cycle largely stops. Hundreds of common medications reduce saliva, as do some medical conditions and head and neck radiotherapy. If your mouth is dry, that should change your prevention plan, your fluoride regime and your recall interval.

No: frequency of sugar exposure matters more than total quantity, and other factors such as dry mouth, deep grooves in the biting surfaces, exposed root surfaces from recession, and existing restoration margins all contribute independently of diet. Someone with a modest sugar intake but significant dry mouth or several old fillings can have meaningfully higher risk than someone with a sweeter diet but good saliva flow and no restorations.

Yes, and in some ways adults face additional risk factors children generally don't: exposed root surfaces from gum recession, which decay faster than enamel, medication-related dry mouth, and the accumulated margins of years of restorations, each one a potential site for new decay to start. Decay is not a childhood condition that adults age out of; risk simply shifts to different sites and causes.

Decay is caused by bacterial plaque converting sugars into acid that attacks the tooth locally where plaque sits, typically between teeth and in grooves. Erosion is caused by acid contacting the tooth surface directly, from acidic foods and drinks, or from stomach acid in reflux or vomiting, and tends to affect broader smooth surfaces instead of the specific sites plaque favors. Both remove mineral, but they have different causes and need different prevention strategies.

Where the decay is confined to enamel and has not cavitated, arresting it with fluoride, reduced sugar frequency and better cleaning can be genuinely preferable to placing a filling, because every restoration begins a cycle that eventually needs redoing. This is a considered clinical decision based on where the lesion sits, not a failure to treat, and it should come with a defined review point to confirm the lesion is actually staying stable, not progressing unnoticed.

Decay itself does not physically jump between teeth, but the bacteria that cause it are shared throughout the mouth and the same conditions, frequent sugar exposure, plaque left undisturbed between teeth, reduced saliva, that caused decay on one tooth are equally present at the neighboring contact point, so it is common to see decay develop at a similar site on the adjacent tooth around the same time, which can look like it 'spread' even though the mechanism is really shared risk instead of direct transmission.