In short
Tooth decay is an infectious bacterial disease that progressively destroys the hard tissues of the tooth (enamel, then dentine, then pulp). It affects more than 90% of adults at least once in their lives and remains, alongside periodontal disease, the leading cause of tooth loss. Caught early, it can be treated in a single painless session. Left unchecked, it can lead to a root canal or even extraction.
At Chantepoulet Dental Clinic in Geneva, cavity screening is a built-in part of every check-up, using a protocol that combines clinical examination, low-dose X-rays and, where needed, a high-definition intraoral camera.
What exactly is tooth decay?
A cavity is not a “hole” that appears spontaneously in the tooth. It is the visible end point of a long biological process, sometimes stretching over months or years.
The mouth is permanently home to several hundred bacterial species grouped together in a biofilm called dental plaque. Some of these bacteria, mainly Streptococcus mutans and Lactobacillus, metabolise dietary sugars and produce organic acids. These acids lower the pH at the surface of the tooth and gradually dissolve the minerals in the enamel. This is the process of demineralisation.
As long as the acid attacks stay occasional, saliva (rich in calcium, phosphate and bicarbonates) is able to remineralise the enamel. But when the imbalance becomes chronic, for example through frequent snacking, insufficient brushing or poor-quality saliva, demineralisation wins out. The enamel eventually gives way, the lesion progresses into the softer dentine, then reaches the pulp, where the nerves and blood vessels sit.
That is usually the moment when pain appears. And it is also the moment when things are already well advanced.
The different stages of decay
Understanding the stages of a cavity makes it easier to see why early detection matters so much.
Stage 1: the white spot (early caries). The enamel is starting to demineralise but remains intact. A dull white spot appears on the tooth surface. At this stage, the lesion is fully reversible with a remineralisation protocol (fluoride, reinforced hygiene, sometimes resin infiltration).
Stage 2: enamel caries. The cavity has formed but is still confined to the enamel. No pain, no sensitivity. Only a professional examination or an X-ray can detect it. Treatment consists of a simple composite filling.
Stage 3: dentinal caries. The lesion has crossed the enamel-dentine junction. The tooth becomes sensitive to cold, heat and sweetness. Because dentine is much softer than enamel, progression speeds up noticeably. Treatment is still a filling, but a more extensive one.
Stage 4: pulpal caries. The bacteria reach the pulp. Pain becomes spontaneous, throbbing, sometimes unbearable at night. At this point, saving the tooth almost always requires a root canal treatment.
Stage 5: abscess and necrosis. The pulp dies and the infection spreads into the bone around the root. An abscess can form, with swelling, fever and a risk of general complications. The tooth is sometimes still salvageable, sometimes doomed to extraction.
The message is simple: the earlier a cavity is treated, the shorter, more painless and more affordable the treatment. An early-stage cavity can be fixed in 15 minutes. An abscess takes several sessions and a much heavier financial commitment.
Causes and risk factors
Cavities are not genetic fate. They are a multifactorial disease, which means they result from the combination of several elements.
The central role of diet
Not all sugars are equal. What matters is not so much the total amount of sugar consumed as the frequency of exposure. A can of soda downed in one go at midday is far less cariogenic than a sugary coffee sipped over two hours. With each intake of sugar, the oral pH drops for roughly 20 to 40 minutes. Frequent snacking keeps the mouth in a near-permanent state of acid attack.
Acidic drinks (sodas, fruit juices, flavoured waters, white wine) add a direct attack on the enamel, independent of bacterial action.
Oral hygiene
Inadequate brushing, in duration, technique or frequency, lets dental plaque build up. Without mechanical intervention, the biofilm thickens, becomes more pathogenic and eventually mineralises into tartar, which in turn promotes new cavities and inflamed gums.
Skipping floss or interdental brushes is a very underestimated factor: the majority of adult cavities form between the teeth, where a toothbrush never reaches.
Saliva
Saliva is the most powerful natural ally against decay. It dilutes acids, provides the minerals needed for remineralisation and contains antibacterial proteins. Anything that reduces salivary flow therefore increases the risk of decay: certain medications (antidepressants, antihistamines, blood pressure treatments), mouth breathing, dehydration, radiotherapy of the head and neck, Sjögren’s syndrome.
Anatomical and genetic factors
Some people have very deep grooves in their teeth where plaque accumulates easily. Others have enamel that is naturally less mineralised. Tooth position also plays a role: crowding complicates hygiene and encourages contact cavities.
Lifestyle
Smoking, alcohol, chronic stress (which dries the mouth and encourages bruxism), lack of sleep and certain general conditions such as poorly controlled diabetes significantly increase the risk of decay.
How do you recognise a cavity?
The catch is that an early cavity does not hurt. By the time pain arrives, the lesion has already progressed well. Here are the warning signs, in order of appearance.
A white, brown or black spot on a tooth, especially in a groove or near the gum, always deserves professional attention. Sensitivity to cold, heat or sweetness that lasts a few seconds after the stimulus is a classic signal. Pain when chewing, persistent bad breath despite good hygiene, or the feeling that floss keeps fraying in the same spot are all clues not to ignore.
And of course, spontaneous pain, especially at night, radiating to the ear or jaw, should prompt a quick consultation: this is usually a sign that the pulp is affected.
That said, the only reliable way to diagnose a cavity is a professional examination, supplemented if needed by bitewing X-rays that reveal interdental cavities invisible to the naked eye. That is exactly what a check-up visit is for: finding cavities before they make themselves felt.
Modern cavity treatments
Dentistry has evolved enormously over the past twenty years. We have moved from a “drill and amalgam” approach to minimally invasive dentistry, which aims to preserve as much healthy tissue as possible.
Remineralisation (very early stage)
For an initial cavity (white spot), it is now possible to avoid the drill entirely. High-concentration fluoride varnish, infiltration of a fluid resin that seals the micro-porosities of the enamel (ICON technique), adjustments to hygiene and diet: the lesion stops, sometimes even disappears visually.
Composite fillings (enamel/dentine stage)
This is the most common treatment. The dentist removes only the infected part of the tooth, disinfects the cavity, then fills it with a tooth-coloured composite resin. The composite is cured with an LED lamp, sculpted to recreate the natural anatomy, and polished. One session, usually painless (local anaesthetic if needed), with an invisible cosmetic result. The grey amalgam fillings of the past have almost entirely disappeared from modern practice.
Ceramic inlays/onlays (extensive decay)
When the cavity is too large for a direct composite but the tooth can still be preserved, a custom ceramic piece is made and bonded into the cavity. Stronger than a bulky composite, more conservative than a crown. Digital dentistry (optical impression, CAD/CAM design, in-office milling) now makes it possible to complete an inlay in a single session in the best-equipped practices.
Root canal treatment (pulpal decay)
If the pulp is affected, the dentist removes the infected pulp tissue, disinfects the root canal system and seals it hermetically. The tooth, now “dead”, is then restored and usually protected with a crown to prevent fracture. Performed under an operating microscope and with modern rotary instrumentation, this treatment has nothing to do with its painful reputation of the past.
Extraction (last resort)
When the tooth can no longer be saved, extraction becomes necessary. It is ideally followed by a replacement option (implant, bridge) to prevent neighbouring teeth from shifting and bone from being lost.
How to prevent cavities effectively
Prevention rests on four pillars, all of them essential. None can make up for the absence of the others.
Brushing. Twice a day, two minutes minimum, with a soft brush and a fluoride toothpaste (1,450 ppm for adults). Technique matters more than force: gentle movements from the gum towards the tooth, systematically covering every surface. An electric brush with oscillating-rotating or sonic action measurably improves effectiveness for most patients.
Interdental cleaning. Floss or interdental brushes, once a day, in the evening. Non-negotiable. This is the only way to act on the areas where most adult cavities form.
Diet. Limit the frequency of sugar intake even more than the quantity. Drink water rather than sodas, finish a meal with a neutral food (cheese, water), avoid snacking. Xylitol (sugar-free chewing gum after meals) has demonstrated a genuine anti-caries effect.
Professional check-ups. A visit every 6 to 12 months depending on risk profile, with scaling and a full examination. This is the only way to spot a cavity at a stage where it can still be stopped without invasive intervention.
Alongside these four pillars, targeted measures may be added on a case-by-case basis: fissure sealants in children and teenagers, professional fluoride applications for high-risk patients, dry-mouth treatments for patients on drying medication, short-course fluoride mouthwashes.
Cavities in children: the specifics
Baby teeth are more vulnerable than adult teeth: their enamel is thinner, their dentine more porous, and cavity progression is significantly faster. A cavity on a baby tooth can reach the pulp within a few weeks.
Contrary to a stubborn belief, treating cavities in baby teeth is essential. An infection on a temporary tooth can damage the germ of the adult tooth sitting below it, cause an early loss that disrupts the eruption of permanent teeth, and plant in the child a lasting fear of the dentist.
The first visit is recommended around one year of age, or as soon as the first teeth appear. Its main purpose is to educate parents: no bottles of milk or juice at night, assisted brushing until age 7 or 8 (a child does not have the dexterity before then), age-appropriate fluoride toothpaste.
The role of regular screening at Chantepoulet Dental Clinic
In Geneva, Chantepoulet Dental Clinic has built its care protocol around a simple idea: it is better to catch ten cavities at stage 1 than to treat a single one at stage 4. In practice, that translates into a systematic clinical examination at every visit, control bitewing X-rays at intervals tailored to each patient’s risk profile, and the use of modern diagnostic tools (intraoral cameras) to visualise early lesions.
The team also offers personalised hygiene coaching sessions, which are especially useful for patients with a high caries risk (people undergoing orthodontic treatment, patients on drying medication, parents supporting their children). When treatments are needed, the team consistently favours minimally invasive and aesthetic approaches: latest-generation composites, ceramic inlays, microscope-assisted dentistry for complex cases.
Located on rue de Chantepoulet, at the heart of Geneva and a short walk from Cornavin railway station, the clinic welcomes adult patients and families alike, and charges fees in line with the Swiss Tarmed/SSO tariffs.
