Digital crown lengthening and home bleaching

A clinical case by our Community member Dr. Elissa Nasr

This article and its content are published under the Author’s responsibility as an expression of the Author’s own ideas and practice. Styleitaliano denies any responsibility about the visual and written content of this work.

The harmony of a smile mainly depends on the balance of three anatomic components: the teeth, the gingiva, and the lips. Excessive gingival display (EGD) is defined as a gingival exposure larger than 2mm when a person smiles. EGD treatment depends on the associated factors and etiology Altered Passive Eruption (APE) is a common etiology of EGD. Crown lengthening surgery (CLS) is indicated for APE treatment, which consists of exposing sound tooth structure with or without removal of alveolar bone.
Fully digital protocols have been developed to increase the accuracy, predictability and success of crown lengthening surgery.

style italiano styleitaliano preoperative gummy smile situation

Fig.1
The patient’s chief complaints were the gummy smile, and the color of her teeth.
She presented excessive gingival display associated with APE from the upper left canine to the upper right canine and an hypermobile upper lip. The treatment plan for APE was one-stage crown lengthening surgery (CLS). In order to improve the esthetics, home bleaching was also performed. Later, botulinum toxin injection was planned to be performed to reduce the mobility of the upper lip, however the patient was satisfied with the results and decided to abstain from the Botox therapy.

style italiano styleitaliano digital smile design according to cbct data

Fig.2
Intra-oral scans, extra-oral Digital Smile Design (DSD) photographs, Cone Beam Computed Tomography (CBCT) were taken. All the data was superimposed.
A digital diagnostic wax-up design was performed. It should overlap the gingival margin to achieve less gingival display. The wax-up is designed according to the DSD and the anatomic crown measures extracted from the CBCT.
The shape and size of the teeth were discussed with the patient before finalizing the wax-up.

style italiano styleitaliano planning for crown lengthening

Fig.3
In the lateral cut view, it was verified that the new margin of the wax-up is coronal to the CEJ observed on the CBCT.

style italiano styleitaliano smile with wax up

Fig.4
The wax-up design cast was 3Dprinted (XFAB 2000; DWS) with cast resin (3D printable resin Invicta 915; DWS). A polyvinyl siloxane index (Aquasil Ultra+, Dentsply Sirona) was made on the printed cast. A mockup was performed to check the occlusion and esthetics (Protemp 4; 3M).

style italiano styleitaliano digitally designed surgical guide for crown lengthening

Fig.5
The crown lengthening surgical guide was designed according to the approved wax-up and mock-up. The surgical guide was printed with a 3D printer (XFAB 2000; DWS) and biocompatible resin (3D printable resin DS5000; DWS).
The crown lengthening procedure was performed by Dr Abdullah Ajili and Dr Lory Abrahamian. First, the gingivectomy was carried out with an electric tip following the inner shape of the windows of the guide. Then, a full thickness flap was made with papilla preservation to make the osteotomy at the level of the bone that corresponds to the upper part of the surgical guide. Finally, the needed osteoplasty was performed.

style italiano styleitaliano close up of surgical guide with open flap

Fig.6
A close up picture of the guide with the open flap.

style italiano styleitaliano check up 3 months after crown lengthening

Fig.7
3 months post-op control photograph exposing the stability of the results using the crown lengthening guide.

style italiano styleitaliano before and after whitening with white dental beauty

Fig.8
3 months after the surgery, home bleaching was performed for 14 days using 16% CP (Teeth whitening gels, White Dental Beauty).

style italiano styleitaliano white dental beauty teeth whitening gels
style italiano styleitaliano white dental beauty teeth whitening gels
style italiano styleitaliano before and after crown lengthening and whitening

Fig.9
Initial situation is on the left. 6 months post-crown lengthening surgery and 2 months post-bleaching on the right.

Conclusions

The treatment of EGD with a CLS is technique sensitive. Using a digital workflow helps the clinician to achieve predictable results.
Minimal invasive bleaching therapy could be used to ameliorate the aesthetics of the smile.

Bibliography

1. Silberberg N, Goldstein M, Smidt A. Excessive gingival display–etiology, diagnosis, and treatment modalities. Quintessence Int. 2009 Dec;40:809–18.
2. Peck S, Peck L, Kataja M. Some vertical lineaments of lip position. Am J Orthod Dentofacial Orthop. 1992 Jun;101:519–24.
3. Mele M, Felice P, Sharma P, Mazzotti C, Bellone P, Zucchelli G. Esthetic treatment of altered passive eruption. Periodontology 2000. 2018;77:65–83.
5. Dym H, Pierre R. Diagnosis and Treatment Approaches to a “Gummy Smile.” Dent Clin North Am. 2020;64:341–9.
6. Robbins JW RJ. Global Diagnosis: The Art and Science of Interdisciplinary Treatment Planning. In: Global Diagnosis: A New Vision of Dental Diagnosis and Treatment Planning. Quintessence Publishing Company; 2016.

style italiano styleitaliano Essential Dentistry kit online on demand course
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