Examination with bitewing X-rays
Lesions between the back teeth cannot be seen directly. Small X-rays taken every two to three years, depending on your risk, show them while they are confined to the enamel.
About this treatmentDental condition · Wimpole Street, Marylebone
Early decay: the stage before a cavity, when the damage can still be undone
Decay is not an event but a process, and it starts long before there is a hole. Every time sugar reaches plaque, the bacteria in it produce acid that draws calcium and phosphate out of the enamel beneath. Saliva puts those minerals back over the following hour or two. When the balance tips towards loss, day after day, the enamel’s surface stays intact but the layer underneath becomes porous and chalky. This is early decay, sometimes called an incipient or white spot lesion. It has no nerve supply, so you will not feel it, and it does not show up as a hole because there is not one yet. The encouraging part is that at this stage the process can be halted and the enamel re-hardened without any drilling at all. Spotting it in time is the whole point of a regular examination, and it is where our Marylebone practice puts a great deal of its attention.
Recognising it
How it usually feels
Chalky white patches on the enamel
Most visible when the tooth is dried; they often sit close to the gum line or around old brace brackets.
A brownish shadow between two back teeth
Seen on X-ray or as a grey tinge through the enamel at the contact point.
Slight roughness the tongue notices
Porous enamel loses its glassy finish before it breaks down.
A brief twinge with something sweet
Suggests the softening has reached the dentine, where the tooth can feel.
Floss that catches or shreds at one spot
The surface has begun to cavitate microscopically.
Nothing at all
The great majority of early lesions are found by a dentist, not the patient.
Behind the symptoms
What's going on
- 01
Frequency of sugar, more than quantity
Each exposure triggers roughly half an hour of acid attack. Six small sugary snacks or sips across a day therefore do far more harm than the same amount eaten in one sitting. Sweetened coffee, energy drinks and mints are common hidden sources in busy working lives.
- 02
Plaque that stays put
Bacteria need time to organise into a mature, acid-producing film. Areas that are missed by the brush, such as the gum margin of back teeth, the grooves on molars and the surfaces between teeth, are exactly where early lesions appear.
- 03
Not enough fluoride reaching the enamel
Fluoride is incorporated into the repairing enamel and makes it more acid-resistant. Rinsing with water straight after brushing, using a low-fluoride paste or brushing only once a day all reduce the protective effect.
- 04
Reduced saliva
Medication, mouth breathing and some medical conditions cut the flow that would otherwise buffer acid and redeposit minerals. Patients with a dry mouth develop early decay on surfaces that would otherwise be safe.
- 05
Orthodontic appliances
Fixed braces create ledges where plaque collects, and white marks around where brackets sat are a well-recognised consequence of imperfect cleaning during treatment. Aligners can trap sugary drinks against the teeth if worn without rinsing first.
Before your appointment
What you can do today
- Brush twice a day with a toothpaste containing at least 1,350 ppm fluoride and spit without rinsing, so the fluoride stays on the teeth.
- Clean between the teeth every day with floss or interdental brushes; this is where most adult decay starts.
- Confine sugar to mealtimes and cut out grazing on sweets, biscuits and sweetened drinks between meals.
- Leave at least an hour after eating before brushing so softened enamel is not scrubbed away.
- Chew sugar-free gum after meals to raise saliva flow and speed up neutralisation.
- Photograph any white patches you can see so that change over time is easier to judge.
These are holding measures, not a substitute for an examination. Use any pain relief exactly as directed on the pack and check with a pharmacist if you take other medicines.
In the chair
How we treat it at Wimpole Street
Fluoride varnish
A concentrated fluoride coating painted onto the affected areas and repeated at intervals. It slows further mineral loss and encourages the enamel to re-harden.
About this treatmentFissure sealants
A thin resin flowed into the grooves of molars and premolars seals plaque out of the deepest crevices. Used in adults as well as children where the fissures are deep and stained.
About this treatmentTargeted hygiene and diet coaching
Our hygienists remove mature plaque, show you exactly where it is collecting and help you find realistic changes to snacking habits that make the difference.
About this treatmentMinimal fillings where needed
If a lesion has broken through into the dentine, a small tooth-coloured filling removes only the softened tissue and seals the tooth.
About this treatmentCosmetic options for white marks
Stable white patches on front teeth that have healed but remain visible can be blended using resin infiltration or micro-abrasion, or masked with bonding.
About this treatmentFees
Costs to expect
An examination at Wimpole Street is expected to be £95, with bitewing X-rays at £20 each where they are due. Fluoride varnish is £40 per visit and a hygiene appointment is from £89. Fissure sealants are quoted per tooth after we have checked that the grooves are sound.
Should a lesion have progressed into the dentine, white fillings start from £185 and are kept as small as the decay allows. Monitoring a stable early lesion costs nothing beyond your routine check-ups, which is one of the strongest arguments for keeping them regular.
Figures are indicative prices for Wimpole Street and are confirmed in a written plan once a dentist has examined you. Fees match our South Kensington and St Paul's clinics.
Don't wait if
When to see a dentist
- You can see a chalky or brown mark that was not there a year ago.
- A tooth reacts briefly to sweet food or cold drinks.
- It has been more than a year since your last examination.
- You had braces and have noticed marks where the brackets were.
- You have a dry mouth or have started medication that causes one.
- Floss catches or frays in one particular place.
FAQ
Common questions
Dried enamel over a porous lesion looks chalky rather than translucent, and bitewing X-rays reveal a triangular shadow at the contact point between back teeth. Some practices, including ours, also use fibre-optic transillumination to shine light through the tooth and highlight the change in density.
The enamel crystals that have partly dissolved can regrow if calcium, phosphate and fluoride are available and the acid attacks stop. Fluoride varnish provides the fluoride, saliva provides the minerals, and your diet and brushing reduce the acid. Over months the lesion becomes harder and often less visible, though it may never look exactly like untouched enamel.
A filling replaces sound tooth structure with a material that will one day need replacing, and each replacement is larger than the last. Where the lesion is confined to enamel, arresting it preserves the whole tooth. We reserve fillings for lesions that have reached the dentine or are visibly cavitated.
Usually every six months for the first year, with a repeat X-ray at twelve to twenty-four months depending on the site. If the shadow has not grown and the surface remains hard, the interval can lengthen. If it has progressed, we treat it before it undermines the tooth.
They are demineralised enamel, so yes, though many are stable and pose no threat once the brackets are off and cleaning improves. Their appearance is the main concern. Options range from doing nothing, through resin infiltration to blend them, to a thin layer of bonding for the most noticeable ones.
Marylebone, W1
Wimpole Street opens 1 October 2026
Leave your details and we will be in touch when the Marylebone diary opens. If the problem cannot wait, the same clinicians are already seeing patients in South Kensington and at St Paul's.
Related conditions
Opening 1 October 2026
Wimpole Street is not yet seeing patients. Until then, please book or call our South Kensington clinic on 020 7183 2362 or our St Paul's clinic on 020 7183 3709. Questions about the new clinic: wimpolestreet@md.co.uk.
Until we open
Need an appointment before 1 October 2026?
The same clinical team already works from two other Medical & Dental clinics. Book at either one now and, if you prefer, move your ongoing care to Wimpole Street once the doors open.
South Kensington
- 20 Old Brompton Road, London SW7 3DL
- Open seven days a week
- 020 7183 2362
St Paul's, City of London
- 5 Ave Maria Lane, London EC4M 7AQ
- Open Monday to Friday
- 020 7183 3709
