Tooth is made of three layers - the outer layer is strong and hard and is made up of enamel, the intermediate layer is of tough dentin and the inner layer is of soft pulp that contains the nerve ending, blood vessels and others cells which retain the vitality of the tooth.
If dental decay is permitted to progress, it results in a deep cavity that may reach the pulp thereby exposing it to the outer environment. Severe erosion or trauma to the tooth can also cause pulp exposure. When the pulp is exposed to the exterior, it develops inflammation and infection leading to pain. There are two ways to get relief from the pain, either a root canal treatment, or tooth extraction. An endodontically treated tooth can function normally in the mouth. If left untreated the tooth develops pain, swelling, etc, and the infection can spread deeper into the underlying bone. We recommend removing teeth as a very last option because natural teeth are the ones best suited for your mouth.

X-ray of teeth before 
X-ray of teeth after
Rubber dam
Rubber dam is a device that is used to isolate a single tooth or a group of teeth from the rest of the oral cavity in order to keep the tooth (being treated) away from saliva and also to increase accessibility. It also prevents accidental swallowing of delicate instruments, solutions, etc. It is used usually in filling procedures and is a must in root canal treatment.

Rubber dam