Dental cavities are notorious and most common disease experienced by humans. Enamel is the most hardest substance and there is no man made material or no technique available which can replace or give back the 100% strength of enamel. Unfortunately since enamel does not have nay nerve supply or blood supply thats why caries isolated to that structures goes unnoticed specially in back teeth. If it occurs in front tooth region and if patient is conscious of his/her looks then they visit dentist for early intervention. Very initial effect of caries on enamel can be stopped by applying remineralising agents or by Fluoride releasing materials. But this seldom happens. 

Once there is loss of continuity in structure of enamel the caries progresses and reaches inner layer called Dentine. This Dentine gives response to caries, temperature change and pressure change inform of sensitivity. If the patient pays heed to the warning signals now, the chances of saving tooth by simple restoration/fillings can be done. The filling will take care of the lost tooth structure.

Negligence and severe pain occurs when cavities become bigger and reaches the blood and nerve supply of the tooth called pulp. If Pain is present only when cold or hot beverages or food taken but subsides immediately the tooth can still be saved but if pain continues ever after cessation of stimuli that means the vitality of tooth cannot be saved and Alas the only option left for patient is Root canal treatment or Extraction.

Early and regular visit to dentist assures successful treatment and maintenance of teeth for long run. But the facts are different most of the patients only report when they have pain or unbearable sensitivity. The treatment protocol and success rate becomes unpredictable. Expenditure also increases in saving or replacing the damaged tooth. Make yearly visit to dentist a habit and enforce it on you family members too. 

Keep smiling and live health.