Thank you for your question. A crown lengthening surgery is most commonly done to expose a tooth in order for a dentist to prepare a tooth properly for a crown. This can be necessary when the tooth exposed above the gum line is too short and will not have sufficient height to allow the crown to be retentive.
Another reason for a crown lengthening procedure is that the tooth has a pre-existing filling that lies under the gum and in order for a proper seal around the old filling, the crown preparation has to encase the pre-existing filling hence the gum level has to be altered and the crown lengthened.
Other less common reasons for a crown lengthening surgery could be dental decay that lies under the gum (e.g. due to an impacted wisdom tooth) and in order for the dentist to restore the tooth properly, the portion of the tooth with dental decay has to be exposed.
Another reason could be to facilitate root canal treatment and repair any perforations at the root level.
In some cases, a patient may have very thick and overgrown gums (i.e hyperplastic gums) and a crown lengthening procedure is done to expose more of the crown of the tooth to achieve a more balanced ratio of gum and tooth show.
A crown lengthening surgery is considered successful when it allows the dentist to achieve his/her aims. It is not uncommon for the gums to rebound after the crown lengthening surgery hence proper treatment timing will ensure greater success. This would mean not waiting too long after the crown lengthening surgery to proceed onto the next treatment of crown preparation.
Hope this helps, and all the very best.
