The restoration of endodontically treated teeth often fails due to mechanical or restorative issues. Success depends on preserving tooth structure, with a 1.5 mm ‘ferrule effect’ being essential for stability. Posts can help in core retention and stress distribution but may also weaken the tooth and increase the risk of fracture. When a sufficient ferrule is present, digital technologies can be employed to rehabilitate teeth using high-load composites, while still achieving the aesthetic quality that is typically achievable only through analog techniques, such as stratified crowns.
Fig.1
A patient presented to the clinic for an emergency consultation after fracturing the crown of a central incisor. After confirming the absence of vertical fractures and mobility, the key question was whether the tooth could be restored or required extraction.
Clinically, the fractured crown exhibited a gingival margin distinct from that of the contralateral central incisor. The uneven gingival margins contributed to an asymmetrical smile, further influencing the treatment approach.
Fig.2
With 2 mm of sound tooth structure around all margins and sufficient space for a gingivectomy, we opted to restore the tooth with a new ceramic crown.
Fig.3
The endodontic retreatment was performed with absolute isolation (Credits: Frederico Morais).
Fig.4
A digital transparent template was fabricated with ideal dimensions to ensure adequate space for the crown. A high-mechanical-strength fluid composite was then injected.
Fig.5
Recent research also suggests that when these conditions are met, a post may not be necessary, as the ferrule provides a secure connection to the restorative material and ensures effective force dissipation.
Fig.6
The vertical preparation was performed using the BOPT technique, which is characterized by the absence of a defined finish line, allowing greater flexibility in designing the emergence profile. This method is particularly preferred in re-restoration cases.
Fig.7
An adapted provisional was provided and relined to adjust the gingival margin and emergence profile.
Fig.8
The provisional crown was relined with acrylic to refine the emergence profile. The gingival margin was marked, and the surface was polished for a smooth adaptation. The 45-degree angle aids in stabilizing the blood clot.
Fig.9
The provisional restoration was placed with chlorhexidine. Due to its strong retention, cement was not required.
Fig.10
After four weeks, the provisional restoration was removed to evaluate the gingival tissues, and the final impression was taken one week later.
Fig.11
The digital impression.
Fig.12
The crown was milled from a white CAD/CAM zirconia block, with feldspathic ceramic layered on the vestibular surface to enhance light transmission in the incisal area. (Credits: Invisible Art Dental Studio)
Fig.13
Before.
Fig.14
After 1 month.
Fig.15
Before and after treatment.
Fig.16
The periodontal tissue showed no inflammation or recession.
Conclusions
Endodontically treated teeth with a 2 mm circumferential ferrule, restored without a fiber post, can withstand fatigue loading similarly to those restored with a fiber post. Additionally, preserving tooth structure helps prevent catastrophic failures.
The injectable composite resin technique, using a transparent silicone index, provides a precise and predictable method for translating diagnostic wax-ups. Digital tools further enhance predictability, ensuring more reliable outcomes in restorative procedures.
Bibliography
- Zicari F, Van Meerbeek B, Scotti R, Naert I. Effect of ferrule and post placement on fracture resistance of endodontically treated teeth after fatigue loading. J Dent. 2013 Mar;41(3):207-15.
- Andrea T, Giolanta LM, Roberto PR. Biologically Oriented Preparation Technique Through a Digital Workflow, a Case Report. J Esthet Restor Dent. 2024 Dec;36(12):1657-1665.
- Loi I, Di Felice A. Biologically oriented preparation technique (BOPT): a new approach for prosthetic restoration of periodontically healthy teeth. Eur J Esthet Dent. 2013 Spring;8(1):10-23.
