A dentist checks for far more than cavities. During a routine check-up they look for tooth decay, gum disease, and early signs of mouth cancer, and they also assess your existing fillings and crowns, cracks and wear, your bite, and any plaque or tartar buildup. They use their eyes, a small probe, and x-rays to spot problems you cannot see or feel yet. In short, a check-up is a quick, whole-mouth screening designed to catch trouble while it is still small.
Tooth decay and cavities
This is the classic one, but decay is sneakier than people think. The dentist looks for soft or discoloured spots on the biting surfaces, but a lot of decay starts between teeth or beneath old fillings where the eye cannot reach. That is what x-rays are for, they reveal hidden cavities early, while a small filling can still fix them.
The health of your gums
Your gums say a lot about your mouth. The dentist checks for redness, swelling, bleeding, and receding gumlines, and may gently measure the little pockets between your gums and teeth with a probe. Deeper pockets can signal gum disease, which is common, often painless, and a leading cause of tooth loss. Caught early, it is usually reversible, so this check genuinely protects your teeth.
Early signs of mouth cancer
This is the quiet, important part. While looking around your mouth, the dentist examines the soft tissues, your tongue, cheeks, the floor and roof of your mouth, and your throat, for anything unusual like an ulcer that has not healed, or a red or white patch. Your dentist is often the first person to notice these early signs, and early detection makes mouth cancer far more treatable. You would not think to look for it yourself, which is a big reason regular check-ups matter.
The condition of existing dental work
If you have fillings, crowns, veneers, or a bridge, the dentist checks that they are still sound. Old fillings can crack, wear down, or leak at the edges, letting decay creep in underneath. Spotting a failing restoration early means a simple repair rather than a bigger problem down the track.
Cracks, chips, and tooth wear
The dentist looks for cracked or chipped teeth and for signs of wear. Flattened or worn surfaces often point to grinding or clenching, frequently at night without you realising. Catching that early can save a tooth from fracturing and may lead to a simple fix like a night guard.
Your bite and jaw
How your teeth meet matters. The dentist checks your bite and how the upper and lower teeth line up, and may feel or listen to your jaw joint for clicking, tenderness, or restricted movement. Bite problems and jaw joint issues can cause headaches, worn teeth, and discomfort, so they are worth picking up.
Plaque, tartar, and your home care
Finally, they assess how much plaque and hardened tartar has built up and where. This shows the areas your brushing and flossing are missing, which is why the check-up is paired with a clean and often finishes with tailored advice for your routine. Simple habits, like those in our guide to preventive dentistry, keep that buildup down between visits.
For children, a few extras
With kids, the dentist checks the same things plus how the teeth and jaw are developing, whether baby teeth are making way for adult ones, spacing and crowding, and early habits like thumb-sucking. Catching a developing issue early can make later treatment simpler. Our guide on baby teeth and their care covers what to watch for at home.
The tools they use
Most of a check-up relies on a few simple things: a small angled mirror to see around each tooth, a fine probe to feel for soft spots and measure gum pockets, and good lighting. X-rays are added when needed to see between teeth and below the gum, and some clinics take photos to track changes over time. It is low-tech in the best way, quick and painless, but very effective at catching the things that hide.
Why a check-up finds what you cannot
The theme running through all of this is early, hidden detection. Decay between teeth, gum disease below the gumline, a leaking filling, early mouth cancer, none of these hurt or show at first. By the time they cause pain, they usually need bigger treatment. A trained eye and an x-ray find them while they are small, which is the whole point of going before anything feels wrong.
Frequently asked questions
What do dentists look for during a check-up? Dentists look for tooth decay, gum disease, and early signs of mouth cancer, and they also check your existing fillings and crowns, cracks and wear, your bite and jaw, and plaque or tartar buildup. They use a mirror, a probe, and x-rays to find problems you cannot see or feel yet.
Do dentists check for mouth cancer at a check-up? Yes. A routine exam includes looking over the soft tissues of your mouth, tongue, and throat for early signs such as a non-healing ulcer or a red or white patch. Dentists are often the first to spot these, and early detection greatly improves the outcome.
Do dentists always take x-rays at a check-up? No, not every time. X-rays are taken when they are needed to see between teeth or below the gumline, based on your risk and how long since your last set. They reveal decay and problems the eye cannot, but they are not part of every single visit.