Added by Michal Matusiak on | Reviewed by Marta Worona

What is a dental filling?

A dental filling is a material which is used by a dentist to fill the cavities (gaps and holes) in the enamel or tooth (dentin). A filling is used by dentists when the tooth has decay, has undergone root canal treatment, has cavities, or has been damaged. Its main purpose is to repair the surface of the tooth and restore its function, as well as to secure the tooth from bacteria, decay or physical damage.

A cavity filling is an alternative to dental crowns or veneers, which are used when the damage is too great to be amended by a filling or onlay. Often a filling is a relatively quick and simple procedure, which is used for small cavities in the teeth. Dental crowns and veneers are more durable, however the procedure tends to take longer and they are a more expensive option.
If there is a problem with the dental pulp of the tooth, root canal treatment may be necessary. This branch of dentistry is known as ‘endodontics’ – the dental speciality concerned with the study and treatment of dental pulp. This dental pulp consists of nerves, blood vessels and lymph vessels. It can become inflamed and/or infected by bacteria from tooth decay, however, there may be other reasons. irreversible pulpitis occurs when the inflammation and/or pain is so severe that the pulp cannot be saved. Root canal or endodontic treatment is then required
Tooth filling can be made of various materials. The most popular include composite resin in the colour of a natural tooth, porcelain, amalgam (a composition of silver, copper, mercury and other vestigial elements) and, up until recently, the most popular- gold. Since amalgam and gold contain some mercury, they are now viewed negatively by scientists as posing a potential threat to human health.

A filling is also termed an onlay/inlay, depending on the size of the restorative piece. Sometimes these can get confused, so here is a more in-depth explanation of the terms.

Lady during the dental treatment

Main purpose of dental filling is to fill the surface of the tooth which has a hole or cavity and restore its function. It is also securing the tooth from bacteria, decay or physical damage. It is one of the most popular dental procedure.

Dental Filling vs Inlay / Onlay

Inlays and onlays are only other terms for fillings and are used for bigger cavities – filling being the most basic dental restoration. In both cases, these ‘fillings’ require the removal of existing decay and part of a tooth. Smaller cavities require less work and may be completed during one visit using an amalgam or composite filling prepared on-the-spot.

If the cavity is larger the dentist will need to use inlays and the process may be prolonged because the filling piece (inlay) is created in a laboratory in order to perfectly fit the size and shape of the cavity.

Onlays are bigger and cover larger cavities together with the whole tooth cusps. However, they are smaller than dental crowns. Onlays are also produced in a laboratory and cemented onto the tooth in the same way as inlays.

When a filling is used:

You will need a filling in the following situations, when:

  • Your tooth or enamel is eroded, worn down
  • Your tooth or enamel is damaged, chipped slightly and lacks shape to function properly
  • Your temporary filling has fallen out
  • Your tooth has cavities
  • Your tooth is decaying which is producing cavities in the enamel
  • Root canal treatment has been performed to save a natural tooth

How do I know if I need a filling?

Even if you have any of the above-mentioned symptoms, only after a dental check-up will you know for certain that you a dental filling is required. Your mouth will be checked using a small mirror and any abnormalities in tooth surfaces will be examined closely, and , where necessary, x-rays will be taken for further clarification.

Then, if an NHS dentist, a treatment plan will be prepared, or if the work is being done privately the dentist may go on to complete the filling immediately.

What happens when you get a filling?

The first step in filling a tooth cavity is removing the decayed part of the tooth, usually by drilling and disinfecting it. The clean hole will then be filled with the recommended material type.

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Dental filling procedure


So, you might wonder what steps are involved in filling a tooth? It’s a very easy dental procedure.

Doctor dentist

A dental filling is a simple procedure and it starts from a dental checkup, then decay removing and finally placing the on a tooth, afterwards, there is a shaping and polishing

Dental check-up

Before the procedure can begin, you will require a check-up with your dentist.

During the check-up  you can discuss any issues with the dentist,  who will then take the necessary steps.

After inspecting the tooth, the dentist will choose the best type of dental filling. If root canal treatment is required, then the dentist will have to perform this procedure first. This may prolong the process, necessitating up to one or two more visits.

Decay removing

If the tooth is diagnosed with decay, the decayed part of the tooth is first removed by drilling. This may mean using the conventional rotary dental drills or , where appropriate,  newer systems like laser ablation systems and air abrasion devices. Next the cavity is cleansed of any bacteria and debris. Finally the affected area of the tooth is then cleaned, washed, and dried.

How does a local anaesthetic work?

If everything is OK, the dentist will numb your gums by injecting local anaesthetic into the appropriate place. This is painless. A general anaesthetic is not usually used because a local anaesthetic is much simpler and quicker. The numbness from the local anaesthetic can last up to a few hours after the procedure itself. Sometimes the patient may also experience problems with correct enunciation (saying words properly) after a local anaesthetic, so, if you plan anything requiring your verbal skills after the treatment, it may be  better to postpone it.

Less often used is intraligamentary anaesthesia where only the specific tooth is numbed – not the gums and surrounding area.  Not all dentists, however, will offer this procedure.

Tooth filling, shaping and polishing

In the case of so-called direct fillings – i.e. made on the spot – the doctor prepares the dental filling and inserts it into the hole, thus filling in the gap and restoring the tooth’s original shape and function. It’s cured with the use of a UV light to ensure that the filling bonds quickly and securely with the natural tooth structure.

A liner made of glass ionomer, composite resin, or other material may be necessary in some cases in order to secure the tooth’s nerve.

If the material is tooth-coloured then it will have to be built up in layers, with a special laser light hardening each layer. Using the laser light on these multi-layers may take time.

After that a check will be made that the new filling has not changed or inhibited in any way the natural bite pattern. If necessary, the dentist will trim down the filling to a perfect fit and then polish it again.

In the case of indirect fillings, the dentist will install only a temporary filling, most commonly a composite one, for the time being. Another visit is then required for the indirect filling to be placed, because the material is prepared off-site in a laboratory. What are indirect fillings?

Filling replacement

A patient who wants to replace an old filling will discover that the process is quick and painless. Staying with traditional fillings will require only one visit.

What are indirect fillings?

Composite resin and  tooth-coloured direct fillings are very similar to indirect fillings with just one exception: the indirect fillings are prepared in a laboratory and then trimmed by the dentist at the surgery. This requires at least two visits to the surgery  instead of one. However, they are more resistant to damage and last for a longer time.

Dentists use indirect fillings in cases of badly damaged teeth, requiring larger filling materials and sometimes constituting a large part of the tooth. However, if the tooth does not have enough tooth structure for support, then a dental crown will be recommended instead of an indirect filling. Indirect fillings are divided into inlays and onlays. Inlays are smaller, require less work and cover smaller tooth cavities, usually between the cusps of the tooth. Onlays sit on top of the teeth and  cover one or more of the tooth cusps. For this reason, onlays are sometimes called partial dental crowns.

Dental fillings should not be mistaken for dental veneers – which are cemented to the front of the tooth – or dental crowns, which are used when more than 30% of the tooth is missing and offer more resistance to bite pressure.

Sometimes only a small part of the tooth, at the front, is visibly chipped. Patients often think that this can be amended by just ‘sticking on’ a dental filling in the right size, especially as it is such a small defect. In most cases, however, despite its relatively insignificant size, a dental crown will be recommended because fillings do not offer a high enough resistance to biting, grinding and physical pressure produced during eating or drinking and may possibly fall off, thereby causing even more damage.

In the case of indirect fillings – inlays or onlays – the laboratory needs impressions of the teeth in order to prepare the filling with precision.


Inlay, onlay and overlay are cosmetic crown fillings that are used for large cavities when the tooth structure is very damaged, they are more durable and strong and they can last up to 30 years

In addition, a temporary dental filling (read about it below) will be necessary to keep the tooth protected from bacteria and food. At

the first visit, the patient receives a temporary filling which is exchanged for the permanent indirect filling at the second visit.

In comparison to common dental fillings, indirect fillings – inlays, onlays and overlays – offer more durability and strength. Sometimes they can last up to 30 years and in total are not that expensive. The materials used for preparing these fillings will be presented in depth below, but generally speaking, nowadays, tooth-coloured composite resin, porcelain, or gold are most often used.

Onlays vs dental crowns

Any larger tooth damage requires the application of a  bigger single-tooth restoration. Since inlays cover only the space between the tooth’s cusps, they cannot be used for major restorations, whereas onlays cover the cusps, so are a good repair option. A dental crown covers the whole upper part of a tooth, or just part of it, offering more protection and resilience. However, of the two – onlay and crown – dental onlays are the cheaper option.

How long does a dental filling take?

Direct dental fillings do not require a lot of time or complicated procedures to be inserted. So, if the dentist is using  a direct filling, often about one hour is required to complete the whole process. More precision and shaping, especially when it comes to tooth cusps, may take longer, especially if the dentist uses a dental or rubber dam to isolate the tooth.

Where there are several cavities to fill, indirect fillings are being used or  root canal treatment is required beforehand, multiple visits and longer appointments may be necessary. It will depend on the condition of your teeth.

What's a temporary filling and Why would I need one?

Temporary fillings are used under the following circumstances:

  • For any dental treatment that requires more than one visit to the dental office – for instance in the case of all indirect fillings
  • Following root canal treatment
  • After a tooth root and pulp irrigation (washing out with antiseptic and/or antibacterial solution) – which will help the nerves to heal
  • In cases of dental emergencies such as toothache
  • A temporary filling is not designed to last forever, so if, by chance, you forget to visit your dentist for the proper filling to be inserted, then your you will be reminded when your temporary filling falls out, fractures, or wears out within a month or two. Prolonged use of a temporary filling may cause tooth infection or other complications.

How to prevent cavities

Keep your teeth clean

To avoid cavities, which lead to a dental filling, it is important to keep your teeth clean. By brushing your teeth you can remove plaque or debris which is accumulated between teeth.

The most basic and rudimentary condition for avoiding cavities and thus need for dental fillings is, of course, keeping regular good oral hygiene. Brushing your teeth twice a day and flossing once per day should keep your teeth in good condition – providing you don’t smoke or e-smoke. Any plaque, debris and food particles, especially sugar, which has accumulated between your teeth can be easily removed in this way.

The brushing process should take at least several minutes. Avoiding the over-use of mouthwashes is also a good idea as chlorhexidine, which is a common ingredient of mouthwashes can cause discolouration of the teeth.

It is equally important to regularly visit your dentist for check-ups  and the hygienist for scraping, polishing and cleaning. This is the most effective way to prevent and quickly fight off caries and cavities.

If a cavity is left untreated, in time, the tooth will decay eventually lead to more problematic dental issues and diseases. Keep in mind that filling any dental cavity nowadays is a very quick and painless process, so there is no need to worry.

What types of filling materials are available?

Gold filling in a tooth

There are different types of dental fillings e.g. composite, porcelain, silver amalgam or gold filling, the last one can last 20 years or even longer

Several dental filling materials are currently available on the market. Teeth can be filled with gold, porcelain, silver amalgam (which consists of mercury mixed with silver, tin, zinc, and copper), or tooth-coloured composite resin fillings. There is also a material that contains glass particles and is known as glass ionomer, used in a similar way to composite resin.

The factors which have  the greatest influence on the type of dental filling most suitable in your particular case, include the condition of your teeth, insurance policy stipulations, specialist’s recommendation, and of course the cost of the procedure.

Types of dental fillings

Nowadays, there are several options on the market from which to choose. From the most established  materials to the newest the list looks like this:

  • gold – flexible and durable. Usually composed of gold (typically 75%), copper and some other minor metals, but still retaining their gold-colour look. They can last up to 20 years, but are quite conspicuous in the mouth, require multiple visits and are the most expensive
  • porcelain – are called inlays or onlay because they are used to fill larger cavities or gaps, need to be prepared in a lab before cementing to the tooth. Porcelain fillings aren’t easily stained by coffee or tea and can be matched to your natural teeth colour. Porcelain restoration usually covers most of the tooth and costs as much as gold fillings
  • silver amalgam – a newer and cheaper solution. Amalgam fillings are a composition of mercury, silver, tin, zinc, and copper. They look like silver and are durable, but have recently fallen out of favour because of the mercury content, which is both detrimental to human health and known to easily crack in temperatures
  • composite resin – have the advantage that they look very natural – blending in naturally with  the colour of the tooth. The newest resins contain quartz and glass and these in turn offer durability and protection for any medium-sized cavity. Currently they are the most commonly used fillings, despite the fact that they stain easily, chip2 and last only up to 10 years
    glass ionomer – materials like acrylic containing glass particles that are most often used for below gum fillings and dental fillings for children. However, acrylic glass is weaker than composite resin dental fillings and easily wears down and cracks. It costs are similar to composite resin fillings and usually last over 5 years.

Dental fillings comparison

Cast Gold


  • Durable – lasts from 10-20 years (and longer); no corrosion
  • Strong – strong enough to withstand chewing, biting etc.
  • Aesthetic – some people like the look of them


  • Expensive – gold cast fillings usually are the most expensive type of fillings. Up to 10 times higher than the cost of silver amalgam fillings.
  • Requires time – at least two surgery visits
  • So-called ‘galvanic shock’ – in rare cases, if the gold filling is placed immediately next to a silver amalgam filling you may experience a sharp pain (galvanic shock) due to the two metals electrical interaction
  • (Un)aesthetic – most patients dislike the difference in colour this type of dental filling creates in their mouth

Silver fillings (Amalgams)


  • Durability – last 10-15 years, but not as long as gold fillings
  • Strength – very strong and resilient to teeth pressure
  • Inexpensive – cheaper than gold and composite fillings


  • Aesthetics – silver doesn’t match natural teeth colour as composite fillings do
  • Destruction of tooth structure – often large healthy portions of a tooth need to be removed in order to insert silver fillings
  • Discolouration – overall impression of the nearby teeth receives a grey look to them because of the silver filling
  • Easily cracks – depending on the temperature of food and drinks your teeth expand and contract, amalgam in these situations is more prone to cracking and fractures than other filling types.
  • Allergies – despite the fact that silver isn’t a hypoallergenic metal, about one percent of people are allergic to mercury, which is a component of silver amalgams
  • Mercury – despite the fact that some studies proved no link between amalgam fillings and health issues, other studies show it is risky and detrimental to health, because it is released in a vapourized form into the organism of the patient over time, affecting the brain and kidneys. Nonetheless, the FDA considers silver (amalgam) fillings safe for adults and children over six years of age. So is it really dangerous? Let’s check it.

Are amalgam-type fillings safe?

Recently there have been growing concerns over amalgam dental fillings, due to the inclusion in them of the toxic substance –  mercury. Mercury is thought to be responsible for a number of diseases like Alzheimer’s, autism, or sclerosis. Public health organisations like ADA, FDA and others have not confirmed such claims, despite agreeing that mercury is detrimental to pregnant women and may have neurotoxic effects on the human nervous system. There is no scientific data to back up such claims, however, the retreat from silver fillings on the dental market continues. The shift in FDA and ADA’s stand on mercury use in dental fillings is due to lawsuits filed by consumer groups.

Tooth-coloured composite resin fillings


  • Aesthetic look – their colour and shade can be closely matched to the colour of your teeth. Best for the front teeth
  • Great bonding – they bond extremely well to dental structure of the tooth
  • Many uses – they can be used in the cases of tooth decay, or repair chipped, broken, or worn down tooth
  • Saves your natural teeth! – less tooth structure needs to be removed than in silver filling case


  • Impermanent – easily wear down sooner than silver or gold fillings and are fragile, last to 10 years
  • Increased chair time – because of the process to apply the composite material, these fillings can take up to 20 minutes longer than amalgam fillings to place
  • Additional visits – if composites are used for inlays or onlays, more than one office visit may be required
  • Chipping – depending on location, composite materials can chip off the tooth
  • Expensive – composite fillings can cost up to twice the cost of amalgam fillings

Which type of filling is best?

There is no single perfect solution that suits every dental case. It all depends on the condition of the cavities, extent of the damages, necessary treatments involved, aesthetic preferences, allergies to certain substances, and of course the cost of the procedure and materials employed by the dentist.

How long should dental fillings last?

Anytime you drink, eat, chew, bite your nails or even speak you’re possibly wearing down your dental filling, if it is in a place affected by the action. Depending on the area, filling size, health of tooth, or other dental problems, typically dental fillings last approximately:

  • Temporary fillings – about 2-3 months, but keeping them that long may cause dental complications, so remember to exchange them as soon as possible
  • Glass ionomer – usually last 1-5 years, with some exceptions
  • Composite resin – last from 5 to 10 years maximum
  • Porcelain – cost as much as gold but lasts only up to 15 years
  • Silver amalgam – can last from 10 to 15 years before they need replacing
  • Gold cast – last the longest, anywhere from 15 to 30 years

All of the above are, of course, average lifespans, which can be altered by good or bad oral habits.

Dental Filling Problems

Dental Filling Allergies and Deteriorating Fillings

There are many dental filling health problems and issues, though most of them are unlikely if the procedure is performed by a specialist. Risks and complications of having a dental filling are as follows:

  • Ongoing hypersensitivity to temperature, air and pressure should be investigated immediately
  • Pain while eating or speaking – this means that the filling is affecting your bite and should be trimmed down by the dentist.
  • Toothache after filling – may point to the need for root canal treatment at a dental surgery, or be just a typical response to a filling, and will subside in time. However, if it is constant and keeps you awake at night you must immediately go back to your dentist.  There could be other complications.
  • Itching and rashes –  if the patient is allergic to the filling material. Allergies to silver fillings are very few, less than 100 cases have been reported by ADA, and, if diagnosed, require filling replacement. Skin rashes and itching are the most common symptoms of allergic reactions to amalgam filling – the mercury or nickel contained in the composition are the usual culprits
  • Very occasionally marginal leakage can occur.  This is where fluids or bacteria get between the filling and the ‘wall’ of the tooth.  The bacteria may irritate the dental pulp and this can lead to the necessity for root canal treatment
  • Wearing down of a dental filling – regular check-ups allow the dentist to check whether a dental filling is wearing down. The patient is unlikely to discover this by himself.
  • Dental fillings falling out – often due to incorrect cavity preparation for the dental filling. Also due to a fracture of the filling or natural tooth.


Does Dental Insurance Cover the Cost of Composites?

Most dental insurance plans cover the cost of the composite fillings up to the price of the silver filling, then the patient may have to pay the difference.


Happy clean tooth

Good oral hygiene; teeth brushing, using antibacterial mouthwash and regular visits at the dentist is the key to healthy and strong teeth

How Should I Care for My Teeth With Fillings?

To maintain fillings, you should follow good oral hygiene — visiting your dentist regularly for cleaning, brush with a fluoride toothpaste, floss and use an antibacterial mouthwash at least once daily. If your dentist suspects that a filling might be cracked or is “leaking” (when the sides of the filling don’t fit tightly against the tooth) this means that debris and saliva can seep down between the filling and the tooth, and lead to decay.  X-rays are needed to assess the situation. If your tooth is extremely sensitive, if you feel a sharp edge, if you notice a crack in the filling, or if a piece of the filling is missing, call your dentist for an appointment.

Teeth fillings before and after

There are different kinds of dental fillings, there can be front teeth fillings, back teeth fillings, composite fillings, etc.

We present below dental fillings before and after photos of our previous patients.

Done in Magnadent

Done in Magnadent

Done in Magnadent


Dental fillings are a cheap alternative to dental veneers and crowns, especially if funded by the NHS or inserted abroad, where you can obtain fillings at less than half the price in the UK and USA. What’s also important, patients can get secured for their medical trip, which makes their travel and stay abroad much safer. Clinic Hunter & AXA Partners have created a health shield dedicated solely to medical tourists.

Get the insurance for treatment abroad:


Michal Matusiak

In 2014 Michal graduated from John Paul University of Lublin.
An English teacher with language skills that he can use to present selected topics in an attractive way. Translator and interpreter of publications for many academic clients, including conferences and press conferences. His achievements include book translations, operating instructions, professional documentation. Michal conducted almost 400 hours of classes at English levels A1, A2, B1, B2 in one semester. He also runs Business English for adults, companies , TELC (The European Language Certificate) courses and worked in different private language schools in Lublin, Poland since 2013.

He easily makes contacts and builds relationships, which results from the experience of the teacher. He is not afraid of technological innovations and he successfully used them in his work more than once. Organizer of academic and official events, presenter and educator. Fluent in education philological, pedagogical, and work experience as lector and coach in other fields of activity.

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