CASE REPORT |
https://doi.org/10.5005/jp-journals-10063-0154 |
Veneers on Devitalized Teeth: The Role of Adhesive Dentistry in Esthetic and Functional Therapies
1–3Department of Fixed Prosthodontics, Faculty of Dentistry, Mohammed V University, Rabat, Morocco; Dental Consultation and Treatment Center, Chis-Rabat, Morocco
Corresponding Author: Yassine Amrani Alaoui, Department of Fixed Prosthodontics, Faculty of Dentistry, Mohammed V University, Rabat, Morocco; Dental Consultation and Treatment Center, Chis-Rabat, Morocco, Phone: +212651763677, e-mail: dramranialaoui@gmail.com
Received: 12 January 2024; Accepted: 17 April 2024; Published on: 17 May 2024
ABSTRACT
Devitalized teeth pose a particular challenge in esthetic dentistry. While still functional, these teeth may exhibit esthetic alterations, such as variations in color, changes in shape, or structural fragilities. Faced with these challenges, dental veneers emerge as a promising solution to restore both the esthetics and functionality of devitalized teeth. Dental discolorations are a common esthetic concern. Chemical teeth whitening represents the primary treatment approach. However, some discolorations prove resistant to these techniques, occasionally necessitating prosthetic interventions. This article aims to examine the application of ceramic veneers as an esthetic and conservative solution to overcome the challenges associated with devitalized teeth. We will explore the procedural steps, technological advancements, and clinical considerations that guide this contemporary practice in esthetic dentistry.
How to cite this article: Alaoui YA, Hicham S, Amal EY. Veneers on Devitalized Teeth: The Role of Adhesive Dentistry in Esthetic and Functional Therapies. CODS J Dent 2023;15(2):59–63.
Source of support: Nil
Conflict of interest: None
Patient consent statement: The author(s) have obtained written informed consent from the patient for publication of the case report details and related images.
Keywords: Case report, Ceramic, Devitalized teeth, Veneers
INTRODUCTION
The adoption of ceramic veneers on devitalized teeth is a less common clinical procedure but is gaining popularity in esthetic dentistry. This approach becomes especially relevant due to the esthetic challenges often associated with devitalized teeth, including changes in color and shape over time. Ceramic veneers emerge as a promising esthetic solution, offering the advantage of preserving more of the dental structure compared to full coverage restorations.
Technological advancements and ongoing research in esthetic dentistry provide exciting prospects to enhance the performance of dental veneers. However, a comprehensive assessment of each case, considering esthetic, functional, and anatomical aspects, remains fundamental to ensure the longevity of the restoration and, consequently, patient satisfaction.
CASE DESCRIPTION
Clinical Examination
A 23-year-old patient (Fig. 1) presented at the Prosthodontic Department at the Dental Consultation and Treatment Center in Rabat due to severe discoloration of tooth 21 (Fig. 1). The patient revealed that he had received an endodontic treatment on the tooth due to a trauma that occurred 2 years ago. The patient’s general medical history and extraoral examination showed no particularities. The smile examination revealed limited visibility of the periodontium with an average smile line. Clinically, there was evidence of substance loss at the incisal angle due to both traumatic and therapeutic reasons related to the access cavity for the endodontic treatment. Radiological examination allowed for the assessment of overall tissue loss and the quality of the endodontic treatment, which was deemed unsatisfactory (Fig. 2).
Fig. 1: Initial state
Fig. 2: Radiograph of initial state
Treatment Plan
Due to the limited coronal damage on tooth 21 and the notable dental discoloration observed, the chosen treatment plan involves endodontic retreatment and implementing internal bleaching as a preprosthetic therapeutic measure. This will be followed by coronal restoration using a full zirconia veneer.
Clinical Protocol
Endodontic Retreatment
The protocol entails removing all canal obturation materials from the endodontic system and reperforming cleaning, shaping, and obturation of the canal in a hermetic three-dimensional manner. The primary directive is to ”aim for improvement” while being particularly cautious not to ”exacerbate the situation” (Fig. 3).
Fig. 3: Revision of the endodontic treatment on tooth 21
Internal Bleaching
The methods of bleaching all share the principle of the chemical breakdown of hydrogen peroxide molecules into nascent oxygen, capable of eliminating the main color agents. By lightening the substrate, it becomes more manageable for the prosthetist, and material choices can lean toward more translucent solutions, thereby providing a more natural result (Fig. 4).
Fig. 4: Final result after 2 weeks
Preparation
The current approach involves using the final restoration morphology as a reference for the preparation shape. This morphology is developed in the form of a provisional wax-up that aligns with the esthetic plan (Fig. 5). The study model modified by this wax-up serves as the foundation for creating silicone keys, enabling the fabrication of the esthetic mask and guiding the preparation.
Fig. 5: Wax-up
The preparation begins with a depth cutter bur. Two horizontal grooves, 0.4 mm deep, are prepared (Fig. 6). These grooves are made respecting the convexity of the tooth. The preparation continues with the cervical limit, which is achieved using a fine-diameter round bur, with the mandrel applied against the vestibular face. This round bur precisely establishes the cervical limit while maintaining very shallow depths in this area where enamel thickness is lowest. Due to the significant dental discoloration, the cervical limit has been slightly submerged at the intrasulcular level.
Fig. 6: Creation of horizontal grooves
To better visualize the depth of the preparation, the bottom of each groove can be outlined with a pencil before removing the mask (Fig. 6). Reduction of the involved tooth continues with a chamfer bur, allowing the elimination of persistent enamel substitute between the previously made grooves.
The proximal limit area is crucial as it determines the non-visibility of the restoration in lateral view. Below the contact surface, the limit is marked as close to the interdental papillae as possible by creating a gingival-proximal extension.
The reduction of the free edge, with a thickness of 2 mm, and the preparation of the palatal return are achieved using a chamfer bur. Special attention is given to the placement of the palatal return, aiming to avoid the most concave area of the palatal surface, which is prone to significant mechanical stress and an increased risk of fracture. The use of the reduction key also guides and controls our preparation (Figs 7 and 8).
Fig. 7: Control of the preparation from the proximal view
Fig. 8: Control of the preparation from occlusal view
Impression and Computer-aided Design/Computer-aided Manufacturing
The impression is taken using silicone A with the double-mix technique to accurately capture the cervical limit intrasulcularly. After disinfection, the impression is digitally recorded directly using a tabletop scanner (extraoral).
Prosthetic design begins with tracing the finish line and selecting the insertion axis. A virtual wax-up is then generated using a database of dental morphologies (Fig. 9), taking into account, the imposed criteria (minimum material thickness, cervical limit, antagonist, etc.). This is followed by the computer-aided manufacturing step, which has enabled the production of the entire prosthetic piece in full zirconia 5Y-TZP.
Fig. 9: Virtual modeling
Try-in and Bonding
Once the adaptation, occlusion, and esthetic aspects have been approved, the bonding of the veneer can be considered. The shade of the resin cement was selected using PANAVIA™ V5 Try-in Pastes.
The chosen bonding protocol is based on the APC concept. The APC concept is detailed in three steps:
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Step A involves air-abrading the entire surface of the zirconia to be bonded. It is done using either simple alumina particles or alumina particles coated with silica.
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Step P involves the application of a special zirconia primer containing phosphate monomers.
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Step C involves the use of a dual-cure adhesive composite to ensure adequate polymerization of the composite under the zirconia restoration.
Thus, veneer bonding is carried out after the placement of a rubber dam and etching of the prepared tooth surface. The bonding agent (Panavia F 2.0) is applied to the veneer’s intrados and on the tooth surface to avoid bubbles. A prepolymerization is performed to facilitate excess removal. Then, each surface is polymerized for 20 seconds (Fig. 10). Before a new polymerization cycle, a glycerin gel is applied to the margins. Indeed, during open-air curing, a layer approximately 50 µm thick does not polymerize due to contact with oxygen. The glycerin gel covers this inhibition layer, allowing for more complete polymerization.
Fig. 10: Final result
DISCUSSION
The creation of dental veneers for devitalized teeth is a less common clinical procedure. Devitalized teeth typically change color or shape over time. Currently, with advancements in preparation techniques and dental ceramics, dental veneers emerge as an esthetic solution to address discolorations in devitalized teeth. They provide an alternative to full-coverage restorations, avoiding aggressive preparation of the palatal surface and preserving the dental structure.1 Among the crucial criteria for the long-term success of veneers is the presence of significant bonding support.
A longitudinal study conducted by Zarow et al. assessed the clinical performance of ceramic veneers on both vital and nonvital teeth. The qualitative evaluation showed acceptable results for all restorations, although a ceramic veneer bonded to a vital tooth failed due to secondary caries. Overall, the survival rate of these restorations reached 97.9% after 8 years of clinical performance.2 This result aligns with other studies reporting survival rates ranging from 91 to 100%.3,4
Preserving the residual dental structure is crucial when preparing veneers for devitalized teeth. Minimizing dental substance loss while achieving esthetic and functional goals is a delicate balance that dentists aim to achieve. Various studies in the literature discuss the impact of preparation design on the survival rate of ceramic veneers. Although findings differ across studies, it appears that a palatal return preparation offers superior support for the restoration, distributing occlusal forces more effectively. In the case of fenestrated dental veneers, occlusal stresses tend to concentrate on the incisal third, increasing the risk of restoration fractures. Additionally, reducing the incisal edge can enhance incisal translucency.5-8
Various ceramic materials are recommended for veneer fabrication, including lithium disilicate, feldspathic ceramic, feldspathic ceramic reinforced with leucite, and lithium silicate reinforced with zirconia.9-12 These ceramics exhibit high translucency due to their high glass matrix content, providing satisfactory esthetics. They also demonstrate excellent bonding to the adhesive product through hydrofluoric acid (4–10%) conditioning followed by silanization.13 For these reasons, these ceramics have been chosen for veneer production.13 However, these ceramics have certain limitations, especially in terms of their limited ability to mask significant dental discolorations and increased fragility in reduced thicknesses.11
On the other hand, ceramics with high crystalline content, such as yttria-stabilized tetragonal zirconia polycrystals (Y-TZP), were initially considered only for framework fabrication due to their high fracture resistance and ability to mask substrate discolorations.13 However, in recent years, zirconia ceramics have undergone significant changes in their microstructure and composition14 to increase translucency without significantly compromising mechanical properties, expanding their clinical indications. Therefore, translucent zirconia is currently considered an esthetic material suitable for crafting monolithic crowns, both anterior and posterior, as well as fixed prostheses, including veneers and ultrathin veneers.15 Its primary challenge arises in situations with low mechanical retention of the preparation, given that polycrystalline zirconia is chemically inert and not susceptible to attack by hydrofluoric acid (4–10%), resulting in less effective adhesion compared to silica-based ceramics.14 Studies have reported instances of detachment of zirconia restorations.16 Consequently, various surface treatments have been proposed to alter the zirconia surface and enhance adhesion to resin cements. These include alumina sandblasting followed by methacryloyloxydecyl dihydrogen phosphate (MDP) application or the implementation of a tribochemical treatment followed by silane application.17,18
CONCLUSION
In conclusion, the application of dental veneers on devitalized teeth requires a meticulous and personalized approach. Maximizing the preservation of the remaining dental structure, particularly the enamel, is crucial to ensure durable adhesion. Ongoing technological advancements and research in the field of esthetic dentistry offer exciting opportunities to further enhance the performance of dental veneers. However, a thorough evaluation of each case, considering esthetic, functional, and anatomical aspects, remains fundamental to ensure the longevity of the restoration and, consequently, patient satisfaction. Close collaboration between the practitioner, dental prosthetist, and the patient is essential to define realistic expectations and achieve a balance between esthetics and tissue preservation.
ORCID
Yassine Amrani Alaoui https://orcid.org/0000-0003-2713-399X
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