How we diagnose — your questions answered

The tapping test is called percussion. Your dentist gently taps the tooth, usually with the back end of a mirror handle, first from the top and then from the side, and compares it with neighbouring healthy teeth.

What it tells the dentist

Each tooth sits in its socket on a thin cushion called the periodontal ligament. When that cushion or the bone at the root tip is inflamed, a light tap feels surprisingly sore. Tenderness on tapping can mean:

• Infection at the root tip, often from a dying or dead pulp (the nerve and blood supply inside the tooth)
• A high filling or crown that takes too much of the bite
• Grinding or clenching, which bruises the ligament around several teeth
• Gum disease, when pain is more on side taps
• A crack, sometimes, though a bite test is better for this

Why it is never used alone

A sinus infection during the monsoon can make several upper back teeth tender to tapping at once, with nothing wrong with the teeth. So your dentist reads the tap together with a cold test, an X-ray and your symptoms before deciding anything. Pain on tapping does not automatically mean you need a root canal.

For more on how chairside tests fit together, see our clinical diagnosis page and the diagnosis hub.

That little air syringe your dentist keeps picking up is one of the most useful tools in the room, and it does two quite different jobs.

1. Seeing clearly

Wet enamel reflects light and hides detail. Once a tooth is dried, early decay shows up as a chalky white or brownish patch, the edges of old fillings become clear, and hairline cracks or acid wear stand out. Tartar under the gumline is also easier to spot. This is why your dentist dries each area before looking closely.

2. Testing sensitivity

A short puff aimed at a tooth or an exposed root is a quick sensitivity test. Your dentist watches how you react and asks how long the feeling lasts:

• A sharp twinge that stops as soon as the air stops usually means exposed dentine, from gum recession, brushing too hard or acid erosion. This is often managed with a sensitivity toothpaste, a varnish or a small filling.
• Pain that lingers after the air stops raises suspicion of deeper decay or an irritated pulp (the nerve and blood supply inside the tooth), and needs further tests.

It is uncomfortable for a second, but it gives real information. Please say so if it is too much; your dentist can cover neighbouring teeth with a finger or cotton. Read more on our tooth sensitivity page or the diagnosis hub.

This is the cold test, the most common form of pulp testing. The pulp is the nerve and blood supply inside the tooth, and the cold test is a quick way to ask it how it is doing.

How it is done

Your dentist dries the tooth, then touches it with a cotton pellet chilled with a refrigerant spray or a small stick of ice for a few seconds. A healthy neighbouring tooth, or the same tooth on the other side, is tested first so you know what normal feels like. You are asked to raise a hand when you feel it and again when the feeling goes.

What the responses mean

• Brief cold that fades within a few seconds: usually a healthy pulp.
• Sharp but short, stronger than the other teeth: the pulp is irritated but often recoverable, for example under a deep cavity.
• Pain that lingers well after the cold is removed: suggests irreversible inflammation, which often leads to root canal treatment.
• Nothing at all: the pulp may have died, though heavily filled or older teeth can also respond weakly.

Because results can mislead, your dentist reads them with an X-ray and tapping test. A short, deliberate sting is the price of a much better decision. See our dead tooth page and the diagnosis hub for more.

Your dentist's eyes and mirror are good at surfaces: enamel, the edges of fillings, gums, tongue and cheeks. An X-ray adds the third dimension, through and under those surfaces. Here is what typically shows up only on the image:

• Decay between teeth, where neighbouring teeth touch and the mirror cannot reach. See our page on decay between teeth.
• Decay under old fillings and crowns, which can spread a long way beneath a filling that looks fine from above.
• How close a cavity is to the pulp (the nerve and blood supply inside the tooth), which decides between a filling and a root canal.
• Infection, granulomas and cysts at the root tip, which show as dark areas in the bone and can be painless for years.
• Bone loss from gum disease, and the level of bone around implants.
• Root shape and number of canals, curved or extra roots, and old root fillings that are short or leaking.
• Impacted and unerupted teeth, extra teeth, and the development of children's teeth.
• Calcified canals and internal or external resorption, where the tooth is slowly dissolving from inside or outside.

What X-rays do not show well

A standard X-ray is a flat picture of a 3D object. Fine cracks, early gum inflammation, mouth ulcers and white patches are often invisible on it, which is why the eye examination, probing and bite tests still matter. When the flat picture is not enough, a CBCT scan may be advised. For more, see the diagnosis hub.

The honest answer is: as often as your mouth needs, and no more. Modern guidance moved away from "X-rays every visit" long ago. Your dentist decides based on what they find and how likely problems are in your mouth.

Things that mean more frequent X-rays

• New cavities in the last year or two, or many fillings
• A sweet tooth, frequent sugary chai or snacking between meals
• Dry mouth from medicines or health conditions
• Active gum disease, or a history of it
• Root canals, implants or crowns that need monitoring
• Children and teenagers with developing teeth
• Orthodontic treatment

Things that mean less frequent X-rays

• No new decay for several years
• Healthy gums and good home care
• Recent X-rays already available from another clinic

As a rough guide, check-up X-rays between teeth may be every 6 to 18 months for higher-risk patients and every 2 to 3 years or more for low-risk adults. Symptoms override any schedule: an X-ray to check a painful or swollen tooth is diagnostic, not routine.

Ask your dentist why each X-ray is being taken. If you are pregnant or might be, say so first. More on X-ray safety is on our diagnosis hub.

An X-ray is a tool, not a ritual. Plenty of dental problems are diagnosed perfectly well by looking, probing and asking questions.

Usually diagnosed without an X-ray

• Visible cavities on front teeth and biting surfaces
• Gingivitis (inflamed, bleeding gums) and plaque or tartar build-up
• Mouth ulcers, thrush, cold sores and many white or red patches
• Chipped teeth, broken or lost fillings
• Sensitivity from gum recession or worn enamel
• Pericoronitis, the swollen gum flap over a partly erupted wisdom tooth, though an X-ray helps plan its treatment

Usually needs an X-ray

• Decay between back teeth or under existing fillings
• Toothache where the cause is not obvious
• Swelling, an abscess or a gum boil
• Loose teeth and suspected bone loss
• Before root canal treatment, extractions and implants
• After an injury to the teeth or jaw

If your dentist suggests an X-ray, it is fair to ask what it will show. If a clinic diagnoses a deep problem and recommends a root canal without any X-ray, it is reasonable to ask why. See also our dental pain finder and the diagnosis hub.

In dentistry, as in medicine, there are often two stages to a diagnosis.

Provisional diagnosis

Based on your symptoms and the first examination, your dentist forms the most likely explanation. For example: "This looks like irreversible pulpitis in the lower left molar," or "This white patch is most likely due to friction from a sharp tooth." That working label decides what happens next: an X-ray, a cold test, smoothing the sharp tooth and reviewing in two weeks, or a referral.

Your dentist may also list a differential diagnosis: the other possibilities that have not yet been ruled out. A toothache, for instance, might be from the tooth, the gum, the sinus or even grinding.

Final or definitive diagnosis

This comes once the evidence is complete. It may be the same as the provisional diagnosis, or it may change. A biopsy report, a CBCT image, or how a tooth responds to a temporary dressing can all change the picture.

Why it matters to you

• Ask what the provisional diagnosis is and what else is possible.
• Ask what will confirm it.
• Be cautious about irreversible treatment, such as extraction, based only on a provisional diagnosis, unless it is an emergency.

For unusual patches, lumps or ulcers, the final diagnosis may involve our oral medicine department. More answers are on our diagnosis hub.

Disagreeing with a dentist is normal and healthy. A good dentist expects questions and will not take offence.

Step 1: Ask, calmly

• "Can you show me what you see on the X-ray?"
• "Which test told you that, and what did it show?"
• "What are my options, including the simplest one?"
• "What happens if I wait a few weeks?"

Sometimes a proper explanation resolves the disagreement. Sometimes it confirms your doubts.

Step 2: Ask for your records

Request copies of the X-rays, the written diagnosis with tooth numbers, and the treatment plan with costs. Patients are entitled to their records; clinics may charge a small fee or ask for a written request.

Step 3: Do not start irreversible treatment yet

Extractions, root canals and crowns cannot be undone. Unless you are in severe pain or have swelling, it is reasonable to take a few days to decide. If there is an infection, ask what temporary measure keeps you safe while you seek another opinion.

Step 4: Get a second opinion

Take your records to another dentist and ask for an independent view. Our diagnosis hub explains how to do this well. At AR 32 you can book a consultation; a booked consultation is ₹500, and an MDS specialist consultation is ₹1,500.

The better your records, the more useful the second opinion. Here is a checklist to carry, ideally in one folder or on your phone.

Clinical records

• X-rays, as digital files or prints, with the date taken. Photographs of a screen help but lose detail.
• The written diagnosis, naming each tooth by number.
• The treatment plan: each step, the options offered and the costs.
• Test results, such as cold or tapping tests, if they were noted.
• Previous dental work on the tooth in question, and when it was done.

Your health information

• Current medicines, especially blood thinners, diabetes and blood pressure medicines, and any bone-strengthening drugs.
• Allergies, pregnancy or breastfeeding, and major health conditions.
• Recent antibiotics or painkillers taken for this problem.

Your symptom timeline

Write a few lines: when it started, what triggers it, how long the pain lasts, whether it wakes you at night, and whether it is better or worse now.

What to hold back at first

Describe your symptoms and let the dentist examine you before handing over the first plan, so their view is truly independent.

At AR 32 your own X-rays, notes and prescriptions are in the patient portal, which makes collecting them easy. See our diagnosis hub for more.

When you describe a symptom, a careful dentist does not jump straight to one answer. They first make a mental list of everything that could cause it. That list is the differential diagnosis.

Take a dull ache in an upper back tooth. The possibilities include:

• a deep cavity irritating the pulp (the nerve and blood supply inside the tooth)
• a hairline crack that hurts on biting
• a gum pocket packed with food
• pressure from a blocked sinus during the monsoon cold season
• clenching or grinding at night

Each item is then tested and ruled in or out: cold tests, tapping, a bite test, gum probing and usually an X-ray. Whatever survives every test becomes the working diagnosis.

This matters to you because the wrong item on the list leads to the wrong treatment. A root canal will not fix sinus pain, and a filling will not fix a crack running down the root. If your dentist says "it could be one of two things", that is not uncertainty for its own sake; it is honest reasoning. Ask which possibilities they are considering and what will separate them. You can read more on how examinations work on our clinical diagnosis page and in the diagnosis questions hub.

Before major work on visible teeth, your dentist may take moulds or a scan of your mouth and send them to a dental laboratory. The technician pours models and then builds the planned result on them in tooth-coloured wax. That model is the diagnostic wax-up.

Why it helps

• You see the plan in 3D, not just as a drawing or description.
• Problems show up early. If teeth would end up too long, too bulky or out of line with your lips, it is cheap to change wax and expensive to change porcelain.
• It checks the bite. For worn teeth or full-mouth work, it shows whether the new shapes will let you chew comfortably.
• It guides the dentist. Guides made from the wax-up help shape the teeth only as much as needed, and help make temporaries that match the plan.

It is most useful for veneers, several front crowns, bridges, closing gaps and restoring worn teeth. For a single back-tooth crown it is usually unnecessary.

A wax-up can be turned into a trial version in your mouth, called a mock-up; see the next question in our diagnosis questions hub. Complex aesthetic and full-mouth cases are planned with our Prosthodontics department. Any lab cost for a wax-up is not in our published catalogue, so ask us for it at your consultation.

A wax-up shows the plan on a model. A mock-up puts that plan in your mouth. Your dentist fills a clear guide made from the wax-up with a temporary tooth-coloured material, presses it over your teeth, and lets it set. For a short while, you see roughly how your smile would look.

What you can judge from it

• Length and shape of the front teeth against your lips when you smile and talk
• Whether the result looks natural with your face, or too white or bulky
• How the teeth feel when you say "f", "v" and "s"
• The opinion of family, once you take photos home

Its limits

A mock-up is a preview, not the finished work. The colour and translucency are only approximate, and it can feel thicker than the final restorations. It is also not suitable for every case: where teeth need to be moved, shortened or have gum work, the mock-up can only show part of the change.

The value is simple: it is far easier to say "a little shorter" on a temporary than after porcelain is cemented. If you are planning veneers or several front crowns, ask whether a mock-up is possible before committing. See our crowns and bridges page and our Prosthodontics department.

Clinical photographs are a working tool, not a formality. A dentist sees your mouth for a short time in the chair; a photograph can be studied calmly afterwards, magnified and compared.

What they are used for

• Showing you what the dentist sees. A cracked filling, a worn edge or gum recession is far easier to understand on a screen than described in words.
• Planning cosmetic and crown work. Smile photos show how your teeth relate to your lips and face.
• Talking to the lab. Shade and surface details travel to the technician with the photographs.
• Tracking change. Wear, stains, ulcers or patches can be compared at the next visit to see whether they are growing.
• A record of the starting point, which protects both you and the dentist if there is ever a question later.

Your privacy

Photographs are part of your medical record. You can ask how they are stored and say no to any use outside your care, such as teaching or social media. Our privacy policy sets out how we handle records. Files uploaded to your record can appear in the X-Rays & Files section of your patient portal.

Lip retractors and cheek mirrors feel odd, but the photographs take only a few minutes.

Your mouth cannot travel to the dental laboratory, so a copy of it has to. That copy is made either with an impression (a soft putty in a tray that sets in a few minutes) or a digital scan (a small camera that builds a 3D image). Both aim for the same thing: an accurate model of your teeth, gums and bite.

Why it is needed

• Making something that fits. Crowns, bridges, onlays, dentures, night guards and retainers are made on these models. A poor copy means a poor fit, open margins and decay underneath later.
• Study models for planning. Before braces, full-mouth work or replacing missing teeth, models let the dentist look at the bite from angles impossible in the chair.
• Wax-ups and mock-ups. The planned result is built on these models.
• A baseline. Models show wear, shifting or bite changes over time.

Making it easier

If you gag easily, say so beforehand. Breathing slowly through your nose, leaning slightly forward and using a smaller tray help a lot. An impression usually needs only a few minutes to set.

Whether we take an impression or the case calls for a scan depends on the work planned; ask us at your consultation. Read more on our crowns and bridges page and our crown preparation basics.

If you have heard "3, 2, 3... 4, 5, 3" while lying back in the chair, you were listening to your gums being measured. This is called periodontal charting.

A thin probe marked in millimetres is placed gently into the groove between the tooth and gum, usually at six spots per tooth. Each depth is spoken aloud so the person assisting can write it down without the examiner putting down the instrument. You may also hear words like "bleeding", "recession" or a mobility grade.

A rough guide to what you heard

• 1 to 3: usually healthy
• 4: early warning, often with inflammation
• 5 and above: likely periodontitis, meaning some bone support has been lost

One deep number on a single tooth may be a local problem, such as food trapping or a wisdom tooth. Many 5s and 6s across the mouth point to generalised gum disease that needs a proper treatment plan.

It is perfectly fine to ask for your chart and to have the numbers explained. Ask which teeth worry the examiner most and when the chart will be repeated to check progress. More detail is in our answer on periodontal charting in the diagnosis questions hub and on our periodontitis page.

During a gum check, your dentist slides a blunt probe into the space between each tooth and gum. If a site bleeds within a few seconds, it is recorded as bleeding on probing. Healthy gum tissue is firm and does not bleed with this light pressure. Inflamed tissue is fragile and bleeds easily.

What it tells your dentist

• Inflammation is active. Bacteria in plaque and tartar are irritating the gum at that spot right now.
• Where to focus cleaning. The chart shows exactly which areas need attention, and where your brushing or flossing is missing.
• Whether treatment worked. Fewer bleeding sites at the review visit is one of the clearest signs of healing.

What it does not mean on its own

Bleeding alone does not mean bone loss. Bleeding with shallow pockets is often gingivitis, which is reversible. Bleeding together with deep pockets suggests periodontitis. Smokers and tobacco users sometimes bleed less despite serious disease, because nicotine narrows the blood vessels; so "my gums don't bleed" does not prove they are healthy.

Gums that also bleed when you brush, or leave pink froth in the basin, should be checked rather than ignored. Bleeding can also be affected by blood-thinning medicines, pregnancy and diabetes, so tell your dentist about these. Read more on our bleeding gums page and our gingivitis page.

Two people with the same number of fillings today can have very different futures. A caries risk assessment tries to predict yours, so that prevention is matched to your actual risk instead of being one-size-fits-all.

What is considered

• Your decay history: new cavities in the last few years are the strongest predictor of more.
• Diet and frequency: how often you have sugar matters more than how much. Several sweet chais, biscuits and mithai through the day keep teeth under attack.
• Saliva: dry mouth from medicines, diabetes, mouth-breathing or radiation raises risk sharply.
• Plaque and brushing, fluoride toothpaste use and access between teeth.
• Exposed roots, braces, partial dentures and deep grooves, which trap plaque.

What changes with the result

Low-risk patients may need only routine check-ups. Higher-risk patients may be advised more frequent reviews, bitewing X-rays more often, fluoride varnish, sealants on deep grooves, diet changes and, for dry mouth, saliva support. The aim is fewer drills in future, not more.

Ask your dentist which risk group you fall into and which one or two changes would make the biggest difference for you. See our why cavities form page and the diagnosis questions hub.

A diagnosis says what is wrong now. A prognosis says what is likely to happen next, with or without treatment. In dentistry it is often given for each tooth, and sometimes for the mouth as a whole.

Common terms

• Good: the tooth and its support are healthy enough that, with treatment and care, it should last well.
• Fair: some problems, but manageable with treatment and maintenance.
• Guarded or questionable: success is uncertain and depends on several factors going right.
• Poor: treatment may help for a while, but failure is likely.
• Hopeless: the tooth cannot be kept healthy and is usually best removed.

What shapes it

Remaining tooth structure, bone support, cracks, gum health, your bite, smoking or tobacco use, diabetes, and how well you can keep the area clean. A prognosis can improve, for example after successful gum treatment, or worsen if problems are left alone.

Prognosis is a judgement, not a guarantee. Ask your dentist to explain the reason behind the label, especially before expensive work like crowns or bridges on a tooth. More on how decisions are made is in our diagnosis questions hub and on our treatment planning page.

Some patients find it worrying when a dentist lists everything that might go wrong. It is meant to do the opposite: to replace vague fear with specific, manageable facts.

Why it is done

• Informed consent. You cannot truly agree to treatment without knowing its risks, benefits and alternatives. This is why a written consent form is signed before treatment.
• Realistic expectations. Some sensitivity after a filling, or swelling after a wisdom tooth removal, is normal. Knowing that in advance avoids panic.
• Early warning. If you know which signs are not normal, such as swelling that keeps increasing, bleeding that will not stop, or numbness that lasts, you will call us early.
• Honest choices. A risk that seems small to the dentist may matter to you; for example, a small chance of numbness near a nerve before an important event.

What a good explanation includes

The common, minor effects; the rare but serious ones; what can be done if each happens; and what would happen if you chose no treatment.

Ask questions until you understand. At our clinics the plan is written down so you can decide in your own time. Our working policies include pre- and post-operative instructions, and our emergency page explains what to do if something worries you after treatment.