One of the challenges in restorative dentistry is replacing old restorations. These cases present a treatment-planning dilemma, as often we do not have all of the information about the health and condition of the teeth underneath the original materials. The questions revolve around the structural health of the teeth as well as the original prep design and restorative process. Ceramic veneers add a layer of complexity in that we hope to be able to utilize veneers again for the current treatment plan and need to understand the clinical situation. The original thickness of the ceramic, whether we will be adhering to dentin vs enamel, and the color of the preps are questions that we do not get the answer to until the original ceramic has been removed.
Diagnosis and Treatment Planning
A 64-year-old female, in very good overall health, presented as a new patient after relocating to Arizona. One of her initial concerns was the replacement of her existing anterior restorations. She shared with me that the original restorations were done in 1994. After placement, several of them came off, were recemented, and were ultimately replaced. This process happened over the initial 2 to 3 years and was accomplished by several dentists due to several household moves that occurred in that same period. Ultimately, the upper right canine was replaced with a crown due to trouble keeping a veneer in place, and the dentist advised her to wear a nightguard to protect her teeth and the restorations against damage while she was sleeping. After that, the restorations were stable for many years.
In the last few years, the previous dentist had advised her that 2 of the veneers had “cracks” (observed using loupes) and that they may be nearing the end of their lifespan. She had also noticed some staining and discoloration at the margins and had been wondering if the aesthetics of the restorations could be improved through replacement.
|Figure 1. Preoperative lab photography.||Figure 2. Pre-op lips, at repose.|
|Figure 3. Pre-op retracted view, teeth apart.||Figure 4. Pre-op retracted view, teeth together.|
|Figure 5. Pre-op smile.||Figure 6. Final preps, with labial reduction guide.|
An oral cancer screening and soft-tissue examination were completed. The patient exhibited visible signs of dry mouth, with a reddened appearance to her tongue and soft tissue, and a thick, almost bubbly, appearance to her saliva. She reported taking a low dose of Zoloft daily for anxiety for many years, experiencing some dry mouth as a result. She was not aware of symptom challenges but did say that she drinks a lot of water throughout the day.
She reported wearing a lower full-coverage occlusal guard appliance for many years. She was comfortable with the appliance and credited it as the reason her restorations had not broken after the initial challenges she had experienced. She had no recollection of ever having had any pain or functional issues that caused symptoms. The patient presented with no palpable joint sounds, and nothing was detected on doppler auscultation. Her muscle examination revealed slight tenderness on palpation in the medial pterygoid and lateral pterygoid regions. She demonstrated a normal range of motion and reported no muscle fatigue signs while eating. She presented with a deep overbite and a limited overjet and a Class II canine and molar relationship on the left and a Class I canine and Class II molar relationship on the right. She had moderate lower anterior tooth wear consistent with grinding her teeth.
The upper-right canine had a full-coverage, all-ceramic restoration, and the remainder of the anterior teeth all had existing ceramic veneers. Both canine restorations had visible cracks in the ceramic, as well as staining and the start of recurrent decay at the facial margins. The patient had a history of endodontic treatment on 2 maxillary left molars and had multiple posterior crowns. She reported that she had childhood tooth decay that resulted in having numerous large amalgam fillings. Over time, these teeth were then treated with crowns. The patient also had prior endodontic treatment on her lower anterior teeth, which was reportedly a result of a trauma when she was a child. Bite-wing radiographs and a panoramic (Panorex) radiograph were received upon request from her previous dentist, and, after review, there were no findings. Periapical radiographs of the anterior teeth were taken to confirm that there were no periapical lesions and to verify the integrity of the margins in the existing restorations.
The periodontal evaluation revealed all sulci depths were within normal limits with no mucogingival attachment loss. Her oral hygiene was excellent, and there was no bleeding or evidence of gingival inflammation.
A full set of aesthetic treatment planning photographs (Figures 1 to 5) was taken due to the patient’s expressed interest in replacing her restorations. She reported that, although she had been generally pleased with the appearance of the original ceramics, she was not happy with the discoloration that had occurred over time at the facial margins. She also noticed that spaces had opened up between the teeth toward the gumline that were sometimes trapping food. She shared with me that she originally had them done because she was not happy with the size and shape of her upper front teeth, but she recalled that the color of her teeth was fine.
Her upper central incisor display at repose was at the lower end of normal, and we discussed the option of lengthening her incisors for aesthetic improvement. However, there was a risk that this might present functional challenges as her bite was already deep. The patient had a midline cant to the left at the contact and the incisal edges of the centrals. The incisal edges on the left were shorter than on the right. There was a gentle curve to her smile line and a small step to the incisal edge of the laterals. She had a bilateral buccal corridor insufficiency that could possibly be managed by reducing the buccal prominence of the canine restorations or by including the premolars in the restorative treatment plan. The gingival margins were not level right to left of the midline, and she exhibited some discrepancy in the position of the free gingival margins; however, her gingival display was minimal. The existing veneers displayed some color disparity, possibly created when some of the units had been individually replaced. The patient was generally happy with the color and wanted a natural appearance. Incisal edge characteristics and a chroma gradient could be added to increase the aesthetic result.
|Figure 7. Final preps.||Figure 8. Incisal edge depth cuts.|
|Figure 9. Postoperative retracted view, teeth together.||Figure 10. Post-op smile.|
The patient wanted to have her 6 anterior restorations replaced to improve the aesthetics, replace the cracked veneers, and ensure that the new restorations would not fracture unexpectedly or prematurely. She was generally happy with her existing aesthetics but open to making some changes that could improve the natural appearance of her smile. There was evidence of moderate functional risk due to the presence of tooth wear, her anterior tooth relationship, and the history of challenges with the original veneers. It would be imperative to not restrict her anterior function and increase the risk of ceramic fracture. She was comfortable with her existing appliance and willing to continue to wear an appliance for the foreseeable future to moderate the functional risk. The patient was concerned that the 5 teeth with veneers would eventually need full-coverage crowns, and she wanted to preserve as much of her real tooth structure as possible.
All clinical findings and photographs were reviewed and discussed with the patient in the process of creating her treatment plan. The crown on tooth No. 6 would be replaced with a new all-ceramic crown. We planned to replace the ceramic veneers on teeth Nos. 7 to 11 with veneers, pending the health and color of the natural teeth underneath. Restoring the premolars to correct the flow of the buccal corridor was discussed, but the patient did not want to include them. We would attempt to reduce the visible difference with changes to the buccal tooth position of the canines, if possible. The first step was to work with the laboratory and obtain a wax-up that incorporated the aesthetic changes that we planned. The wax-up was used to create the provisional restorations, which functioned as an aesthetic and functional prototype. Once the provisionals were approved by the patient for their aesthetic appearance and we confirmed that they worked functionally and there were no occlusal or phonetic issues, the ceramics were fabricated to duplicate the customized provisionals. During and after the restorative phase, the patient would continue to wear her lower appliance. At the conclusion of the restorative phase, we evaluated the need for a new appliance vs continuing with her existing one.
Clinical and Laboratory Protocols
Upper and lower impressions were taken for diagnostic models. A Kois Dento-Facial Analyzer (Panadent) was used to mount the upper model and to reference the relationship to the hinge axis (for functional accuracy) and the aesthetic plane to the horizon. The mounted models and photographs were sent to Gold Dust Dental Lab (Tempe, Ariz) along with a proposed treatment plan and instructions to complete a wax-up kit. The wax-up kit was returned with the original models, the wax-up, silicone reduction and provisional matrices, an additive reductive clear matrix (to show the correction of the buccal position of the canines), and a solid model of the wax-up.
Approaching the replacement of existing restorations in the same way as much as possible, and by following the same steps as when preparing natural teeth, creates predictability. One of the places this becomes a challenge is in removing old restorations, then assessing the amount of reduction and ending up with the desired prep design that will meet current aesthetic and restorative outcomes. Having matrices that allow for the assessment of restorative space based upon the diagnostic wax-up is critical to ensuring success. Often, the first thing that we do is remove all of the existing restorative material. This leaves us without some of our visual landmarks and is often the only approach. When possible, it is best to follow the steps of doing a mock-up and reduction depth cuts as a way to control the preparation phase. Then the clinician can evaluate, after proper space has been created, if there is still remaining restorative material or cement that requires removal. The challenges with this approach are having a mock-up that will stick over ceramic well enough to prep through it and then having the ceramic de-bond during preparation.
In this case, the first step of the restorative process was to reduce the buccal contour of the existing canine restorations (using the clear matrix) until the matrix would seat passively. The incisal edge position and labial position of the new restorations would mirror the patient’s existing ceramics with only subtle changes, so a mock-up was not necessary, and depth cuts were done into the ceramic. The preparation protocol was identical to what is done when working on natural teeth. The first step was to place incisal edge depth cuts to ensure 2.0 mm of ceramic length at the incisal. The reduction was then completed using a KS6 diamond bur (Brasseler USA). Next, depth cuts were placed into the labial to create 3 separate planes of space and a curved labial contour; then the labial surface was reduced by connecting the depth cuts. The last step in initial preparation was to break contact. This phase of the preparation was done equi-gingivally for margin placement. Once the initial reduction was accomplished, restorative space was verified using the series of matrices that included an incisal edge reduction matrix and labial reduction guides. Additional reduction was completed as needed. Once adequate space for restorative material was verified, the teeth were checked for remaining ceramic or resin from the original restorations, and all material remnants were removed so that all the prepped surfaces were in natural teeth.
An initial cord (size 000) (Ultradent Products) was placed. The preps were then all polished with fine diamonds running at slow speed. The author utilizes a speed reduction friction grip attachment for use on Brasseler electric handpiece units. This attachment allows the handpiece to run at 20,000 rpm for fine polishing and margin finishing. A second cord (size 1) was then placed over the original 000 cord, and then the prepared teeth were cleaned with a 2% chlorhexidine rinse. A series of photographs was taken of the prepared teeth for the lab team (Figures 6 to 8). The prep shade was determined, and prep shade photos were also taken for the lab team. A final impression was taken (Flexitime Correct Flow/Flexitime [Kulzer]).
Once all of the records for the fabrication of the final restorations were confirmed and prepared to send to the lab, the teeth were provisionalized using a shrink-wrap technique. A 2-stage silicone matrix was used to create the provisional. The prepared teeth were spot-etched by applying phosphoric acid gel for 20 seconds, then rinsed and air-dried. Next, one coat of GLUMA (Kulzer) was applied to the prepared teeth, then blotted to remove any excess. The matrix was loaded with a bis-acryl provisional material and seated over the preps, allowed to set completely, and then removed. The provisionals were then wiped using a 2 x 2 gauze with rubbing alcohol to remove the air-inhibited layer. The small amount of excess material remaining beyond the margin came off easily due to the accuracy of the fit of the 2-stage matrix. A mosquito diamond was then used to finish the provisionals and to open the gingival embrasures well enough to allow for the use of a floss threader. Finally, occlusal adjustments were made, as needed, and the provisionals were polished.
The patient was brought back in 2 weeks to review the provisional restorations. Once the patient approved the aesthetics and functional success was verified, an impression and photos of the provisionals were taken for the laboratory team, and the fabrication of the final ceramic restorations was begun.
The dental laboratory team fabricated 6 restorations using a proven and aesthetic pressed all-ceramic (IPS Empress Esthetic [Ivoclar Vivadent]). The incisal edges were cut back and layered to create incisal aesthetic/characterization effects. Finally, the all-ceramic restorations were etched in the lab using hydrofluoric acid and then returned to the dental office for the delivery appointment.
The provisionals were removed and the preparations cleaned with 2% chlorhexidine, and then the restorations were tried-in to verify the fit and to adjust and polish the contacts. The last step of the try-in was to place the restorations with try-in paste and allow the patient to verify if we had achieved the final aesthetic result that she desired. Next, the intaglio surfaces of the restorations were cleaned using a universal cleaner (Ivoclean [Ivoclar Vivadent]) and then treated with a universal primer (Monobond Plus [Ivoclar Vivadent]). The restorations were seated with a light-cured resin cement (Variolink Esthetic LC [Ivoclar Vivadent]). Following cementation and removal of any excess cement, the occlusion was checked and adjusted as needed (Figures 9 and 10). The patient returned for a postoperative visit, in which some final occlusal adjustments were made to eliminate minor fremitus on the upper laterals.
By listening to and understanding the patient’s treatment goal, taking care to develop a detailed treatment plan after a thorough diagnosis, and working in close collaboration with the dental lab team, the desired functional and aesthetic results were realized.
In this case, functional risk was managed by copying the functional surfaces of the patient’s existing restorations, as that occlusal design had worked well for her for many years. Had we decided to change the lingual or incisal edge position of the new restorations, greater time would have been required to verify that a functional issue had not been created that would result in future challenges involving premature de-bonds and/or fracture of the new restorations.
When tooth preparation is approached in the same manner as with natural teeth, as demonstrated in this case report, the clinician is able to make adequate space for new restorations and to conserve the patient’s existing tooth structure, thus avoiding more aggressive full-coverage restorations.
The author would like to thank the talented team of dental technicians at Gold Dust Dental Lab (Tempe, Ariz).
Dr. Brady is in private practice in Glendale, Ariz. She is an internationally recognized educator, lecturer, and author. With an extensive history in leadership, she is currently director of education for the Pankey Institute. Dr. Brady has also developed a vast library of online instruction at the websites leeannbrady.com and restorativenation.com. She can be contacted via email at firstname.lastname@example.org.
Disclosure: Dr Brady has received honoraria from Ivoclar Vivadent, GC America, DMG America, and the Pankey Institute.