29 April 2020

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Crown lengthening from an esthetic point of (re)view

Edoardo Mancuso

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Crown lengthening is one of the most common surgical procedures in periodontal practice and it is used to reestablish the biologic width in a more apical position, to avoid its violation that may result in bone resorption, gingival recession, inflammation or hypertrophy.

Crown-lengthening procedures in posterior areas have been intensely investigated, while crown lengthening performed for esthetic  reasons in anterior areas is still a matter of debate.
 A paper written by Prof. Zucchelli  and his team, with the purpose of describing the surgical and restorative phases in the esthetic crown-lengthening procedure has been recently published on “Periodontology 2000”.

The first section described in the paper concerns the correct approach to the flap design, explaining how a valid placement of the primary incision must be based on the probing depth and on the amount of keratinized tissue available.
The article suggests that the papillae area should be elevated split-thickness in order to obtain a precise post-surgical adaptation, while, where the bone tissue has to be removed, a full-thickness elevation should be made in order to easily gain access to the bone and to preserve the periosteum. Once an adequate amount of bone has been exposed, it is advised to perform a split-thickness dissection to facilitate the apical anchorage of the flap in the desired position.
For the palatal region a thinned palatal flap approach is suggested, taking great care not to make the incision too far from the gingival margin in order to avoid excessive exposure of palatal bone, especially in the case of a shallow vault or a deep palatal vault with thick soft tissue. As of the ostectomy and osteoplasty the article suggests that for the removal of supporting bone, the amount of bone resected is determined by the extent of the crown lengthening required, preferably carrying out presurgical biologic width or supra-osseous gingiva measurements, in order to personalize the extent of bone removal.
Considering that the amount of nonsupporting bone required to be removed has not been quantified in the literature, a subjective clinical judgment it is recommended before deciding whether osteoplasty is needed. The management of the provisional prosthetic restoration is a fundamental step to achieve an optimal esthetic.

The paper recommends that the provisional prosthetic restoration phase should start 3 weeks after the surgery, in order not to interfere with the re-establishment of the biologic width and to condition the soft tissues during the period of maximal regrowth.
This approach offers also the advantages of a more conservative abutment preparation and the possibility to avoid the provisional relining at the end of the surgery. The goal of any esthetic surgery is to mimic, as much as possible, the natural aspect of soft tissues and to donate a harmonious aspect to the surgical area. t
Therefore, it's  fundamental for the clinicians, before performing a crown lengthening procedure, to carry out thorough pre-surgical analysis, especially regarding the tissue biotype and on the individual soft-tissue regrowth after the surgery.

For additional informations: Crown lengthening and restorative procedures in the esthetic zone