Hi, since you have already consulted your dentist, the solutions have already been given for u. For your queries 1.there are so many reasons for which a root can be infected, but the most common one is decay. 2. One more thing I wanted to add here is there is no surgery for doing a root canal treatment. It's a chair side treatment done under local anaesthesia to save the tooth( preferably by root canal specialists) . 3. There is no remedies for pain until there is a treatment being rendered. 4. If replacement is needed u need to decide which material u r gona select and of course the ceramic the costliest is better ( u can discuss about different materials with your dentist) Take care of your mother .

Lower right end tooth ? (1) if it's a wisdom tooth (last molar, also called third molar): usually 3rd molars get infected because this tooth is difficult to brush as it is inaccessible. This tooth erupts after age of 20 to 30 years. After removal of this tooth there is no need of replacement . (2) if it's not a wisdom tooth, first molar or second molar then a root canal has to be done and get a crown (metal/ceramic/zirconia) Visit a dental clinic and ask for an oral diagnostician and an endodontist (specialist in root canal) (3) have a regular dental check up for every 6 months to avoid further tooth/oral disease. Thank u.

Hi the basis to all your questions would be better if we have an x-ray to see but since you are saying its a root canal treatment 1. Infection generally shows near the root tip in the periodontal ligament area as its the least resistant area 2. Avoiding depends n multiple factors mostly oral hygiene 3. Further measure can only be decided by the doctor based n your course of treatment as it varies from patient to patient. 4. Yes full ceramic is the best option available

Can't really comment without looking at the xray but a re-root canal treatment if rct already  done previously could solve the problem. A course of antibiotics should also be done. Ceramic crowns are very good options.