Cavities, also known as tooth decay or dental caries, are small holes that form in the hard outer surface (enamel) of the teeth. Cavities are caused by bacteria that produce acid that eats away at the enamel. If left untreated, cavities can grow larger and deeper, eventually reaching the inner layers of the tooth  called dentin and pulp. If the pulp becomes infected or damaged, it can lead to pain and may require root canal treatment to remove the infected tissue and save the tooth.

Signs and symptoms of a cavity vary depending on the extent and location.  If a cavity is at the initial stages/just beginning, there will be no symptoms at all.

If the cavity gets larger and involves deeper layers of tooth symptoms include :

• Food lodgement.
• Tooth sensitivity on consuming hot, cold, or sweet foods.
• Spontaneous tooth pain without any apparent cause.
• Pain in the tooth may increase on biting and chewing.
• Signs of a cavity are black, brown spots or visible holes on the tooth. 

If you are experiencing any of these symptoms, it is important to see a dentist for an evaluation.

During a filling, the dentist will numb the area around the tooth to minimize any discomfort. The dentist will then remove any decay or damaged tissue from the tooth and clean out the area. Once the tooth is clean, the dentist will fill the area with a filling material, such as composite resin, amalgam, or gold. The filling material is shaped and polished to match the contours of the tooth. 

You may feel little or no sensitivity after a tooth filling. If you feel sensitivity, it’s normal & usually subsides in a day or two.

There are several different types of filling materials that can be used, including:

Composite resin: This is a tooth-colored filling material made of a mixture of glass and plastic. Composite resin can be matched to the color of your teeth, so it is a good choice for filling cavities in visible areas of the mouth.

Amalgam: This is a filling material made of a mixture of metals, including silver, copper, and tin. Amalgam fillings are strong and durable, but they are not as aesthetically pleasing as composite resin fillings.

Gold: Gold fillings are made of a mixture of gold, copper, and other metals. Gold fillings are very strong and can last for many years, but they are also more expensive than other types of fillings.

Other materials: Other materials that may be used for fillings include porcelain, glass ionomer cement, and zinc oxide eugenol.

The lifespan of a filling can vary depending on the type of filling material used, the location of the filling, and the patient's oral hygiene habits. In general, composite resin and glass ionomer cement fillings last for about 5-10 years, while amalgam and gold fillings can last for 15-20 years or longer. It is important to maintain good oral hygiene and see your dentist regularly for check-ups and cleanings to help extend the lifespan of your fillings.