Hello If the cap fits properly then you can go for the same if not then you have to go for a new one

yes some time it can be used but only after clinical check up it can be decided.

Same cap can be used

Yes sometimes we can use the same cap,but we can decide this after doing clinical evaluation

The most common reason for the cap to come off is the loss of integrity of the interface between the cap and the natural tooth. This usually occurs due to poor oral hygiene leading to plaque accumulation which leads to acid formation which further causes dissolution of the cement which bonds the cap to the tooth. If the cap is intact and so is the tooth on which the cap was fitted it can be cleaned and Re cemented. Otherwise the tooth will require some repair if it has got cavitated and in that case a new Crown will be fabricated based on a new impression. And the distinction between the two treatment options will lie on the clinical evaluation of the tooth and the cap. Regards.