Restorative Interface in Esthetic Dentistry – Zirconia

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.

55 year-old patient came to the office complaining of his unpleasantly-looking crown (21) and gingival color changes. Luckily, gingival levels on 11 and 21 were optimal. An impression was taken to fabricate a provisional crown.
Treatment was planned as follows:
Vertical prep
Temporary crown (biodynamic soft tissue shaping)
Zirconia Crown

aidite style italiano styleitaliano
aidite style italiano styleitaliano
styleitaliano style italiano abutment after old crown removal

Fig.1
After crown removal, endodontic treatment and build up were needed in order to proceed with tooth preparation and prosthetics. In the picture you can see how the abutment looked after removing the old crown.

styleitaliano style italiano abutment after removing old crown

Fig.2
Although a chamfer preparation could still be performed on this tooth, since clinical and anatomical crown coincide, meaning previous tooth preparation is still supragingival and we could still prepare the chamfer juxta-gingival, a vertical preparation was chosen to better control soft tissue contour.

styleitaliano style italiano isolation of dental abutment

Fig.3
Isolation of the abutment right before build-up.

styleitaliano style italiano build up of dental abutment

Fig.4
Tooth abutment build-up.

styleitaliano style italiano vertical preparation of dental abutment

Fig.5
With deletion of the pre-existing finishing line and controlled invasion of the sulcus we can create space for biotype conversion (soft tissue thickening). The clinical and biological advantages in achieving a thick biotype are:
Stabilization of soft tissues
Reduction in gingival color changes
Better esthetics

styleitaliano style italiano relining of temporary crown

Fig.6
The temporary crown was relined following the biodynamic soft tissue shaping concept.

styleitaliano style italiano temporary crown for soft tissue conditioning

Fig.7
The temporary crown is key to achieving gingival thickness and gingival margin stability. The margin of the temporary crown becomes the new prosthetic CEJ for new gingival forms and profiles (biodynamic soft tissue shaping). After finishing of the margin, the provisional crown was cemented.

styleitaliano style italiano conditioning soft tissues with temporary crown

Fig.8
Temporary crown after cementation.

styleitaliano style italiano dental abutment at impression day

Fig.9
After 1 month tissue conditioning, we were ready for impression.

styleitaliano style italiano zirconia crown

Fig.10
Monolithic zirconia crown with super polished zirconia margins.

styleitaliano style italiano super polished zirconia crown

Fig.11
Monolithic zirconia crown with super polished zirconia margins.

styleitaliano style italiano final single zirconia crown

Fig.12
Final result.

styleitaliano style italiano before and after single zirconia crown

Fig.13
Before and after.

Conclusions

Vertical tooth preparation becomes a powerful tool in achieving esthetics. The finishing line is the crown margin itself, and, from day 0, right after tooth preparation, we can manipulate soft tissues with the temporary crown. After one month, soft tissues are thicker and ready for final impression and crown.
Moreover, choosing the right material for the dental crown is important, since the margin of the final crown is the landing zone for soft tissue stability. Although there are different opinions on optimal material choice, it cannot be denied that zirconia as a material offers substantial advantages over other choices, due to lower adhesion of bacteria, less inflammatory response in soft tissue and esthetics.
Final positioning of the crown margin is 0.5 mm apical to free gingival margin, and biocompatibility is higher when utilizing zirconia.
However, the response of the soft tissue might not only depend on the type of material, but also on the polish degree of the material’s surface. That’s why it is important to have a super polished margin for long term soft tissue stability.

Bibliography

Loi I, di Felice, A. Biologically oriented preparation technique (BOPT): a new approach for prosthetic restoration of periodontically healthy teeth Eur J Esthet Dent. Spring 2013;8(1):10-23.
Conrad HJ, Seong WJ, Pesun IJ. Current ceramic materials and systems with clinical recommendations: a systematic review. J Prosthetic Dent. 2007;98: 389–404
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.
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.
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

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