A clinical case by our Community member Dr. Elissa Nasr
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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.
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.
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.
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.
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).
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.
Fig.6
A close up picture of the guide with the open flap.
Fig.7
3 months post-op control photograph exposing the stability of the results using the crown lengthening guide.
Fig.8
3 months after the surgery, home bleaching was performed for 14 days using 16% CP (Teeth whitening gels, White Dental Beauty).
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
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