Pain stopping is not the same as healing
An infected tooth can stop hurting while the infection continues. If your pain went away on its own, that is still a reason to be examined.
During treatment
A rubber dam is used during root canal treatment. This is standard practice, not an optional extra.
General dentistry
Fillings, scaling, extractions and paediatric dental care are part of general dentistry. Whether any treatment is needed can only be decided after an examination.