Managing gingival levels in anterior prosthodontic rehabilitation

A clinical case by our Community member Dr. Stefano Conti

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.

In prosthodontics, when restoring fractured teeth in the anterior zone, a few clinical considerations must be taken into account. Esthetic success must involve management of gingival levels, which is especially challenging in the anterior area. Thus, orthodontic extrusion and/or modified crown lengthening are to be evaluated before starting treatment. When a fracture line locates in close proximity to or below the alveolar bone crest, the the junctional epithelium and the connective tissue attachment are likely to have been involved.

style italiano StyleItaliano subgingival fracture before orthodontic extrusion

Fig.1
This type of fracture constitutes a challenge as it involves biological, functional, and esthetic issues, especially when the fracture occurs in an esthetic area. This 21-year old patient was referred to our clinic to restore his fractured upper right lateral incisor. After clinical evaluation, we decided to proceed with a minimally invasive approach (orthodontic extrusion and modified crown lengthening, build-up and vertical preparation of the tooth).

style italiano StyleItaliano orthodontic extrusion and modified crown lengthening

Fig.2
In the first place, orthodontic extrusion and modified crown lengthening were performed.

style italiano StyleItaliano digital study of gingival levels

Fig.3
The gingival contour of the lateral incisors should lie more coronal to the central incisors and canines, and be bilaterally symmetrical. This ideal scenario represents the Class 1 gingival height. However, variations in the positioning of the gingival margin of the lateral incisors can occur. In this case, in order to achieve symmetrical gingival architecture of lateral incisors, upper right lateral incisor gingival zenith had to be relocated apically.

style italiano StyleItaliano apical repositioning of gingival level

Fig.4
The upper right lateral incisor gingival zenith was relocated apically and symmetrical to upper left lateral incisor. The new gingival architecture (right) was achieved by controlled invasion of sulcus while performing a vertical preparation. By positioning, with proper timing and design, a new crown margin along the finishing area, we can modify gingival architecture and create space for biotype conversion (soft tissue thickening).
The clinical and biological advantages to achieving a thick biotype include:
Stable soft tissue
Reduced gingival color changes
Better esthetics
Biodynamic soft tissue shaping, meaning the temporary crown’s margin becomes the new prosthetic cemento-enamel junction for new gingival forms and profiles

style italiano StyleItaliano lithium disilicate crown on model

Fig.5
A disilicate crown (Cameo Dental Glass Ceramic, Aidite) with super-polished margins was fabricated by the lab (DT Furlotti Gianluca, Parma, Italy).
The margin is the prosthetic cemento-enamel junction, and is located 0.5 mm apical to the new gingival margin.

aidite style italiano styleitaliano
aidite style italiano styleitaliano
style italiano StyleItaliano lithium disilicate CAM blocks and crown

Fig.6
The finishing line is the crown margin itself, which can be shortened or extended both in temporary or final restoration at different intra-sulcular levels, without harming the quality of fit and without invading the epithelial attachment.

style italiano StyleItaliano prepared abutment with teflon tape

Fig.7
The prepared abutment ready for cementation.

style italiano StyleItaliano cemented lithium disilicate crown on lateral incisor

Fig.8
Crown after cementation.

style italiano StyleItaliano final aspect with apically repositioned margin on upper right lateral incisor

Fig.9
The gingival contour of the lateral incisors is now bilaterally symmetrical.

Conclusions

For selected cases, vertical tooth preparation becomes a powerful tool in achieving esthetics. The finishing line is the crown margin itself, and right after tooth preparation we can manipulate soft tissues with a very minimally invasive approach.
Material choice for the crown restoration is also important since the margin of the final crown is the landing zone for soft tissue stability.
Final location of the crown margin is 0.5 mm apical to the free gingival margin. Although biocompatibility and long term stability seem higher when restoring with zirconia crowns, the response of soft tissues might not depend solely on the type of material, but also and even more importantly, on the polishing status of the material’s surface.

Bibliography

1. Loi I, di Fellice A.Biologically oriented preparation technique (BOPT): a new approach for prosthetic restoration of periodontically healthy teeth
2. Eur J Esthet Dent. Spring 2013;8(1):10-23.
3. Conrad HJ, Seong WJ, Pesun IJ. Current ceramic materials and systems with clinical recommendations: a systematic review. J Prosthetic Dent. 2007;98: 389–404
4. Silva NR, Thompson VP, Valverde GB, Coelho PG, Powers JM, Farah JW, Esquivel-Upshaw J. Comparative reliability analyses of zirconium oxide and lithium disilicate restorations in vitro and in vivo. J Am Dent Assoc. 2011;142(Suppl 2):4S–9S.
5. Kim JH, Lee SJ, Park JS, Ryu JJ. Fracture load of monolithic CAD/CAM lithium disilicate ceramic crowns and veneered zirconia crowns as a posterior implant restoration. Implant Dent. 2013;22(1):66–70.
6. Goodacre Cj, Campagni Wv And Aquilino Sa. Tooth Preparations For Complete Crowns: An Art Form Based On Scientific Principles. J Prosthet Dent 2001; 85:363-76
7. Kang CM, Peng TY. E!ect of thickness of different types of high-translucency monolithic multilayer precolored zirconia on color accuracy: an in vitro study. J Prrosthet dent. 2021 Oct;126(4):587

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