Crown lengthening is a surgical procedure performed by a dentist, or more frequently a periodontist, where more tooth is exposed by removing some of the gingival margin (gum) and supporting bone.

[3] The remaining crown of the natural tooth needs to be sufficiently long to have adequate retention and resistance to withstand occlusal (biting) forces.

If a dental restoration invades the STA, chronic inflammation is likely to occur which then causes pain, gum recession, and unpredictable loss of alveolar bone.

[12][13][14] In dentistry, the ferrule effect is, a "360° collar of the crown surrounding the parallel walls of the dentin extending coronal to the shoulder of the preparation".

Recent studies suggest that, while adequate ferrule is desirable, it should not come at the expense of removing too much remaining tooth and root structure.

Removing bone for a crown lengthening procedure will effectively decrease the bony support available for surrounding teeth and unfavorably increase the crown-to-root ratio.

Thus, it would be prudent for patients to thoroughly discuss all of their treatment options with their dentist before undergoing an irreversible procedure such as crown lengthening.

[22][23][24][25][26] Crown lengthening is often done in conjunction with a few other expensive and time-consuming dental procedures (e.g. post and core, endodontic treatment) with the ultimate goal of saving the tooth.

Consequently, substantial amounts of attachment may have to be sacrificed when crown lengthening is accomplished with an apically positioned flap technique.

Difficult procedure for patients to tolerate, increased post-operative pain [28] Source:[27] Orthodontic tooth movement can be used to erupt teeth in adults.

As such, the units required must be extruded a distance equal to or slightly longer than the portion of sound tooth structure that will be exposed in the following surgical treatment.

Forced tooth eruption is indicated where crown lengthening is required, but attachment and bone from adjacent teeth must be preserved.

A scalpel is used to sever supracrestal connective tissue fibres, thereby preventing crystal bone from following the root in a coronal direction.