Dr. Alexander Declerck | Dr. Tommie Van de Velde
Case Report : Anterior Single Tooth Restoration
A new biomimetic approach for single tooth replacement with a long-term (semi-)temporary restoration
ALL CLINICAL CASES
Faced with the replacement of one single anterior tooth, the treatment goal is to reconstruct the previous functional and esthetic aspect of the lost tooth in harmony with the existing dentition. This however is only valid when the appearance of the remaining teeth is considered satisfactory for the patient. Trying to blend-in one lost tooth will always be a challenge given the complexity of the natural tissue and its evolution over time.
This case report describes an approach where a less demanding effort of the dental technician and a more predictable treatment by the dentist has lead to a very satisfying result for both the patient as the dentist and dental technician. A result in terms of esthetics and cost-benefit ratio.
A patient presents in the office with complaints about mobility and eruption of tooth 21. There is pain caused by an acute infection around tooth 21 (fig. 1).
Gender : Male
Ethnicity : Asian
Date of Birth : 29/07/1981
Smoker : Yes, 1p/d
Medication : No
Based on clinical and radiographical examination the diagnosis was general periodontitis with a severe acute infection around tooth 21 and peri-apical lesions around tooth 31 and 21. Oral hygiene was insufficient and a lot of sub -and supra gingival calculus was noticed (fig. 2).
Initial periodontal treatment with scaling and root planing in 2 sessions was proposed together with oral hygiene instructions. Tooth 31 responded negative on sensitivity tests, and the patient was referred for endodontic treatment. One and three month recall appointments were given to evaluate the resolution of the periodontitis.
After follow-up, tooth 21 was considered lost and oral hygiene was still insufficient. The patient was also unwilling to stop smoking. The periodontist referred the patient to the restorative dentist for extraction and esthetic provisionalisation of tooth 21.
Considering the intact crown of tooth 21, it was proposed to connect this to the neighboring teeth after extraction in order to provide adequate esthetics and function (fig 3-6).
The extracted tooth was reduced to the crown and a small part of the root. Followed by a retrograde extra-oral endodontic treatment to remove the pulp chamber in order to avoid future discoloration of the crown by necrotic tissue. The pulp chamber was sealed with flowable composite. After extraction and elimination of the granulated tissue from the socket, a suture was placed with a spongostan (Ethicon, Johnson & Johnson, Cincinatti, US) to cover the bloodcloth. Subsequently a dental dam (Isodam Heavy, Sigma Dental Systems, Fiensburg, Germany) was placed to create proper isolation in order to predictable bond the customized crown to tooth 11 and 22 using flowable and nanohybrid composite (Filtek Supreme XT, 3M Espe, St Paul, Minnesota, US). Final steps were finishing and polishing of the interdental embrasures to establish proper interdental cleaning (fig. 7).
Having resolved the acute problems for his specific oral situation, the patient was send back to the periodontist to follow-up the periodontal problems and discuss future treatment.
Recall showed improvement of oral hygiene, however far from perfect. The general periodontal condition was good, however there was a poor prognosis of tooth 21 because of the extent of the local bone defect. The bone loss around tooth 21 also compromised the periodontal situation and esthetics of tooth 11.
During discussion with the patient about the future treatment, he showed no interest in resolving other occlusal problems, nor improvement of the esthetic appearance.
The proposed final treatment concluded reconstruction of the bone defect and future implant placement upon motivation to reduce the smoking habit.
Six months after extraction, the bone defect was reconstructed using a combination of Platelet Rich Fibrin (PRF) and Deproteinised Bovine Bone Mineral (DBBM) (Bio-Oss, Geistlich, Switserland). A full-thickness mucoperiostal flap was raised to expose the bone. Cortical perforations were performed with a piezocision device (Piezosurgery, Mectron, Mectron s.p.a, Italy). Blood (80 ml) was collected from the patients arm and centrifuged into PRF membranes. Four membranes were cut to combine with the biomaterial. The mixture PRF-DBBM was moulded to augment the bone in a buccal dimension. A resorbable membrane (Osseoguard flex, BIOMET 3i, Palm Beach, USA) was used to cover the biomaterial and fixed with sutures. The remaining PRF membranes were used to cover the site to increase tissue thickness and to enhance wound healing. The surgical area was closed for primary intentional healing with non resorbable sutures. The buccal flaps were immobilised by periostal incisions and horizontal mattress sutures with resorbable vicryl sutures. Three months later an implant ( Biomet 3i, Palm Beach, USA) was placed (fig. 8-9) in a 2-stage approach. Extensive surgical augmentation, such as soft tissue grafting, was not performed due to the lack of motivation for further aesthetic improvement and the patients smoking habits. Once the implant was osseointegrated, the implant surgeon referred the patient for prosthetic reconstruction.
Given the natural aspect of the splinted crown 21 in harmony with the anterior dentition, a recently tested approach was used to restore the implant (Van de Velde, Inspyred 2015).
An impression of the implant was made to design a zirconia abutment (color VITA A3,5) together with a lithiumdisilicate coping (fig. 10-13). The zirconia abutment with the lithiumdisilicate coping was tried onto the implant.
The crown of tooth 21, already more than a year in place, was further reduced to a buccal veneer. Any problems related to space or fit could easily be detected on the model. The autologous buccal veneer was further adapted in the proper buco-cervical position to establish a nice harmony within the anterior arch and support the gingival tissue. When the size and volume of the veneer was found ideal, the bonding procedure could start (fig. 14-16).
Silica particles (Cojet, 3M Espe, St Paul, Minnesota, US) were blasted (2bar) on the zirconia abutment to prepare a bonding substrate following silanization (Monobond Plus, Ivoclar Vivadent, Liechtenstein) and adhesive application (Heliobond, Ivoclar Vivadent, Liechtenstein). The lithiumdisilicate coping was etched using 5% Hydrofuoridic acid for 20 seconds followed by ultrasonic cleaning and the application of silane (Monobond Plus, Ivoclar Vivadent, Liechtenstein) and adhesive (Heliobond, Ivoclar Vivadent, Liechtenstein). The lithiumdisilicate coping and zirconia abutment were connected using a dual cure composite cement (Variolink II, Ivoclar Vivadent, Liechtenstein). After removal of cement excess and intense polymerization, the bonding procedure to connect the veneer to the lithiumdisilicate coping was continued. The enamel was etched for 30 seconds, using 37% phosphoric acid and extensively rinsed and dried. Adhesive was applied (Heliobond, Ivoclar Vivadent, Liechtenstein), followed by a high chromatic dentin light cure composite cement (Variolink Veneer, Ivoclar Vivadent, Liechtenstein). The lithiumdisilicate veneer was again prepared as previously described. Both of the substrates got connected with the composite cement and light cured for 60 seconds on each side after removal of composite excess. Before try-in, the restoration was finished with addition of dentin composite to mimic the root-emergence and create an ideal emergence profile. The restoration was connected to the implant for try in and evaluation of tissue pressure and contactpoints(fig. 17-18).
After feedback and approval of the patient, the restoration was connected to the implant using a torquewrench to 30 Ncm2. The screw-acces-hole was sealed with teflon-tape and composite color A3,5 body shade (Filtek Supreme XT, 3M Espe, St Paul, Minnesota, US). A new appointment was scheduled for evaluation of the rehydration and proper tissue setting around the implant supported crown (fig. 19-20).
Discussion
The rationale behind this treatment philosophy is the experience that the restoration of a single tooth is a time-consuming treatment, especially when we consider the amount of lab time necessary to create a perfect blending-in of the restoration with the neighbouring teeth. Based on experience and in consultation with the dental technician, the lab time spend in this case was about 2 hours. Taken into account that there was a waiting time between creating the cast, designing the abutment and lithiumdisilicate coping and having the milled abutment and pressed lithiumdisilicate coping. If the technician would also need to create the ceramic crown, an extra time of 10 to 12 hours would be spend on color determination, try in, first bake, second bake and finishing procedures.
The idea to use a zirconia abutment and a lithiumdisilicate coping is the fact that long term sustainability of these type of restorations is still unknown considering bonding strength and strength of the natural veneer on the long term. As such, there are two levels where future intervention can take place. If degradation of the natural veneer would occur, a preparation procedure could be performed to the level of the lithiumdisilicate coping. Further treatment would then be a restorative procedure well known from ceramic veneers on natural teeth. If debonding or cracks of the lithiumdisilicate coping would occur, future treatment would be to take a new impression of the situation similar as we are dealing with a provisional implant supported restoration in the anterior aspect. Meaning to use an individualized impression coping to create a new abutment with a ceramic crown
The esthetic aspect of the black triangle caused by the bone loss around tooth 11 is for sure inadequate. The low smile line however can hide this defect almost completely (fig. 20).
It has to be identified that this approach is very case specific. In most of the cases, the crown of the patient is heavily damaged by trauma or old restorations. Nevertheless, there are still numerous cases where dentists have to deal with single tooth replacement in cervical root resorption cases with a history of dental trauma or acute periodontal infection. We believe that this approach can help to establish a predictable treatment on short term, midterm, or in this case maybe longterm as a temporization of other esthetic dental treatment.
Conclusion
The use of an autologous veneer of a natural tooth is a predictable treatment to create a new restoration mimicking the esthetics of the previous situation. However, many technical factors related to abutment design and bonding procedures need to be respected. Many of these technical factors are widely described in the literature and therefore can be defined as evidence based. The treatment outcome however needs long term follow-up before this approach as such can be considered as the golden standard when faced with these specific cases. The basic idea of ‘primum non nocere’ is respected and if any problem (e.g. debonding) would occur, there is always the possibility to return to the well known approach of creating an abutment with a ceramic crown.
Acknowledgement
This case was treated in co-operation with Faris Younes (periodontist), An Van Kerkhoven (endodontist), Dr. Tommie Van de Velde (implantologist) and Ben Vernaillen (dental technician).
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ALL CLINICAL CASES
