When a dental caries severely decayed. The nurve is removed and filled.
Next time core iscemented the tooth and the preparation for crown restration is done.This preparation is very difficult for dentist.The proper procedure shoud bedone for the correct treatment.
In case a crown does not fit on your tooth,gum desease (periodontitis)
occurs around the tooth.because dental plaque remains and you can not remove this dental diposit.
In other hand,if a dentist injure periodontal tissue, the inflamation occurs around the tissue.