Dental / Cavity Fillings


A dental filling is used to treat a small hole, or cavity, in a tooth caused by decay over a period of time. A dentist removes the entire decayed tooth material and then fills the cavity with an appropriate filling material. Suitable filling material is offered by the dentist based on the clinical condition. For example, if you need a filling for your anterior teeth he may suggest a tooth coloured filling but if the same is needed for your back or posterior teeth, she/he may suggest something that is strong to resist biting forces of the back teeth and not consider aesthetics. There are several types of filling materials currently available in the market to repair or fill the tooth cavities, including:

  • Composite filling
  • Amalgam fillings.
  • Gold fillings
  • Glass ionomer

Amalgam Fillings –

Amalgam fillings is the common type of filling used by dentists worldwide for around 150 years.. Amalgam fillings are made from a mixture of different metals like mercury and silver, tin. It is thus dark coloured and cannot be suggested for use in the front teeth. Amalgam is used most often for fillings in the back teeth. These fillings are very hard and strong usually lasting very long and resist the biting forces extremely well. Owing to its durability, strength, and cheaper cost, amalgam has long been considered and still is the material of choice, especially for certain types of restorations in posterior teeth. Since amalgam doesn’t adhere well to certain dental tissues and for good retention to the tooth by mechanical means, the dentist needs to prepare undercuts in the cavity, and thus requires him/her to remove larger quantities of tooth material. It takes longer time to harden after placement.

Composite fillings-

They are tooth-coloured materials made up of a mixture of plastic and fine glass particles, used to restore decayed teeth. Composites are also used by cosmetic dentists for smile improvements by changing the colour of the teeth or reshaping teeth. Since Composite fillings match the colour of the teeth they are most often suggested for use on the front or anterior teeth which are visible on mouth opening or smiling.

Composites offer some advantages over Amalgam fillings like less cutting of tooth structure by chemical bonding directly to the teeth, close resemblance to natural teeth colour. Composite fillings nicely allow a dentist to match the patient’s existing teeth to give a natural appearance.

Hence composite fillings have become popular for this exclusive reason of delivering a natural looking smile. The only disadvantage is the material that is not as strong as other options. Therefore it can be used as a small filling in teeth that experience only a moderate amount of pressure for chewing food.

Procedure-After careful tooth preparation and isolation to keep it clean and dry, the dentist typically adds the composite material in several layers and carves them with specialised instruments to the desired shape. Each layer is hardened with a blue light by a process called curing. Since the composite resin is rapidly cured with a light, a freshly restored tooth with composite material is immediately functional unlike those restored with Amalgam taking time to harden. The dentist lastly finishes and polishes the filling with a bur to prevent staining and early wear. Composite resin wears out more quickly and easily than amalgam especially if used inside large cavities or those put to strong biting force. But more recent Composites seem to be promising in durability factor. Nevertheless they seem to be a great choice for small restorations of anterior teeth and premolars with excellent outcomes.

Cons of Composite fillings-Some patients may experience postoperative sensitivity after restoration of tooth with Composite material. The shade of the composite can change slightly if the patient drinks tea, coffee or other teeth staining foods. If the patient is concerned about future change in the colour of the Composite our dentist can place a clear plastic coating over it to avoid that.Life of composite filling is lesser compared to Amalgam especially in larger restorations. Other challenges include polymerization shrinkage, and demand the dentist’s perfection and technique proficiency .

How much do Composite fillings cost? Generally speaking Composites are very expensive compared to Amalgam but each has its own advantage. Your dentist can help you decide based on your clinical status. Tooth coloured fillings are now preferred choice over amalgam or gold fillings, probably for their cosmetic benefit.

Gold Fillings –

Gold fillings also called Inlays or Onlays. They are indirect fillings made from a mixture of gold ,copper and other metals. Since they are indirect fillings need fabrication in a dental laboratory hence require more visits to the dental clinic. They are extremely durable and long lasting filling option that can last up to twenty years. This type of filling lasts longer than any other type of cavity fillings. Gold fillings are yellow coloured and do not match the natural white colour of your teeth .They are incredibly expensive, costing six to ten times more than amalgam and hence their durability comes at a steep cost. A gold foil involves placement of gold directly in a restoration. They are single sitting based restoration like the amalgam and composite fillings. Generally suggested for use in fillings that are small. Gold foil treatment is rarely performed by dentists.

Glass Ionomer –

They are made from addition of an acid and base like acrylic and fluoroaluminosilicate, a component of glass to form a salt called Glass Ionomer. Strong trait of Glass ionomers is that they are biocompatible, chemically bonding to the tooth. Also release fluoride that can heal caries lesions or prevent future decay. If a lesion is identified before it ends up in a cavity, a glass ionomer restoration can be placed next to it that could slowly release fluoride into that tooth, and therefore heal it, before a cavity develops. Glass ionomers expand and contract at the same rate as the tooth around them, hence they are compatible coefficient of thermal expansion. Glass ionomer restorations require less removal of tooth than conventional amalgam restorations. Unlike Composite resins they tend to work well in moist environments. Glass ionomer filling is most often used in people with a severe decay in the part of the tooth that extends below the gum line an area often not subjected to much stress from chewing or biting. Glass Ionomer restorations are ideal therapeutic restoration in children with high risk of caries. It is also used for filling baby or primary teeth where moisture management is difficult. Due to their opacity they can be used mostly on posterior teeth but also on anterior teeth. Glass Ionomer fillings are weaker and less resistant to breakage when compared to Composite and Amalgam fillings. So they are less durable and need replacement every few years.

What to Expect from a Cavity Filling Procedure-

  • A local anaesthetic injection like lidocaine is used to help minimize the pain associated with getting a filling.
  • Next, your dentist will carefully remove all the decay from the tooth, using a drill or laser.
  • Once all the decay is removed, your dentist will shape the space to prepare it for the filling. Different types of fillings require different shaping procedures to make sure they stay in place.
  • A base or a liner is placed inside the tooth to protect the nerves inside the pulp of the tooth.
  • Finally, after the filling is placed, your dentist will make sure the filling is properly contoured using burs to finish and polish the tooth surface

What to Expect after a Cavity Filling Procedure:

After a filling procedure, when the anaesthesia wears off patient may experience some of these symptoms occasionally.

  • Sensitivity to pressure, cold air or liquids or sweet foods.
  • Few people can experience numbness, tingling, and slight pain around the site of injection.

Often these symptoms disappear within a few days or weeks of the procedure.

Sensitivity may last for about one to two weeks. Avoid drinking anything hot or cold or eating sweet foods. In case the sensitivity is beyond tolerant levels or if it doesn’t subside after two weeks, schedule an appointment with your dentist.

Your filling may be too high, the commonest reason for the pain you may be experiencing .It can be easily relieved by the dentist checking the occlusal bite and removing the excess filling material. The other rare kind of discomfort experienced after a filling is a very sharp shock called galvanic shock that appears only when teeth in both jaws contact each other. An electric current is produced in your mouth when two metals (one in the freshly filled tooth and one in the tooth above) touch each other causing the sharp shock.

It can happen for instance if a metal crown is fitted in the bottom tooth and a new amalgam filling inserted in the tooth above.

Home Precautions to follow after the Cavity fillings:

  • Avoid eating on your fresh filling for at least an hour and until your mouth is no longer feeling numb.
  • Children should be supervised so that they don’t bite on their numb lips and tongue. If they accidentally bite they can inflict serious injury to their soft tissue.
  • Sensitivity to hot and cold drinks can be expected in some cases which generally goes away in few days. In other cases, prolonged sensitivity could be a sign of a more serious issue. See your dentist in such cases to rule out other issues.
  • Skip sticky and hard candy: Some fillings, particularly silver (amalgam) ones, take time to set at least 24 hrs after the filling procedure. It's best to avoid temporarily eating such sticky foods as they may cause the filling to dislodge easily from the tooth. Hard candy may cause cracks if chewed while the filling material is still setting.
  • One may experience a foreign body feeling in the mouth for few days.
  • To reduce discomfort and soreness try chewing your food slowly and bite lightly. Biting food exerts lot of pressure on the tooth, and this can make it very sore after you get a filling. When chewing your food, take your time to eat slowly. Biting food all the way through makes a forceful contact of teeth which will result in pain. Whenever possible try chewing on the opposite jaw away from the filled tooth.
  • Keep your mouth closed when chewing: Cold air can trigger pain in sensitive teeth in some patients. As such keeping your mouth closed while chewing food will decrease the chance of cold air entering your mouth and causing you pain in the tooth.

Myth buster:

Amalgam fillings are toxic or poisonous!

No. The kind of mercury in amalgam fillings is generally considered not risky for human health. The main exposure to mercury from dental amalgam occurs during placement or removal of restoration in the tooth but it is not of significant concern. Once the Amalgam is set very less quantity of mercury leaks, and that is far below the recommended toxicity levels.Compared to composite and amalgam fillings, glass ionomer fillings lack strength and wear resistance.

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