Full-Arch Implant-Retained Zirconia Prostheses: Balancing Technology and Human Touch

Dr. Justin Moody
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As clinicians, our job is to assess and provide the best treatment plan available to our patients, regardless of our initial thoughts or prejudgments. Asking the patient what his or her needs are and then taking the time to listen will ultimately play a major role in any treatment plan. There is an increased willingness to accept dental treatment from a practitioner when the patient perceives mutual benefits; when there are minimal barriers to care; and when an empathetic, caring approach is exhibited.1 Through technology, we can create value and beauty for our patients while utilizing our knowledge and that of our team along with the best and latest materials available. However, we must not forget, as we are closing cases and selling dentistry, to provide the human touch. Above all, we are here to serve and help our patients (Figures 1 and 2).

CASE REPORT
Consultation

When treatment planning full-arch restorations, we are usually faced with an already edentulous patient or someone who presents with a terminal dentition that requires removal of all their remaining teeth. We all reach an ethical decision when it comes to dealing with terminal dentition, but what we sometimes forget is that the patient has a say in his or her care as well. They are often fed up with temporary quick fixes and seemingly endless problems and appointments. They come to our offices seeking a better solution.2

Figure 1. The full-face, full-smile preoperative photo. Figure 2. The pre-op retracted view of the patient’s anterior maxillary and mandibular teeth.

When offering full-arch solutions to patients, it takes a total team of dedicated professionals who have has a solid understanding of the workflow, finances, and emotions involved to proceed with treatment. One of the biggest mistakes we make as a dental team is prejudging the patient. It is human nature to form an opinion of a person based upon an initial impression, which can be remarkably accurate, but it can also fail us. This process is called thin slicing.3 If we assume that patients cannot afford treatment or that they may not want or accept full-arch treatment, then we may have done the patient a disservice and, ultimately, the office will not do as many comprehensive cases.

The consultation should start with a cone beam computed tomography (CBCT) scan (i-Cat FLX V-Series 3D CBCT System) (Figure 3). It’s the most important initial piece of the puzzle. From this 3-D data, we can formulate a treatment plan based upon available bone volume and focus on treatment options that are possible instead of talking about procedures that may not be doable.

Figure 3. The pre-op CBCT scan (i-Cat FLX V-Series 3D CBCT System).
Figure 4. A face-bow (Kois Dento-Facial Analyzer System [Panadent]) was taken for accurate mounting of the case on a Panadent Articulator (Panadent). These records were sent to the laboratory team to determine the proper midline, the incisal edge position of teeth Nos. 8 and 9, and the plane of occlusion. Figure 5. The side profile of the Kois
face-bow in use.
Figure 6. The post-delivery retracted view of the upper and lower converted dentures (ProSmiles Signature Dentures [ProSmiles Dental Studio]).
Figure 7. A CBCT scan, showing the converted dentures in place as well as the implant positions.

Next is the patient interview, and it is here that we must ask questions and carefully listen to our patients’ desires and concerns prior to the delivery of any treatment plan. In the case example presented here, the patient was a younger female who was partially edentulous and had multiple decayed teeth. She stated that she was not interested in fixing these teeth as they never last. Instead, she wanted to see what was available for total tooth replacement. After discussing her treatment options, she was only interested in the non-removable, most tooth-like replacement, and, in this case, we decided upon a full-arch monolithic zirconia bridge as the final prosthetic choice.4

Workup
The key to creating a quality product that satisfies the patient’s and the doctor’s expectations is starting with good clinical records. High-quality, clinical photos, accurate impressions, a bite registration, and a face-bow record (Kois Dento-Facial Analyzer System [Panadent]) are all essential for effective lab communication (Figures 4 and 5). In addition, historical photos, if available, can be incredibly helpful. They can be used to determine if we can create a smile that the patient once had or one that they never had.5

Utilizing the TeethXpress (BioHorizons) protocol, a set of upper and lower injected Signature Dentures (ProSmiles Dental Studio) was fabricated from these records, along with a duplicated clear acrylic denture. The duplicated denture has a trough cut into the ideal screw-access hole sites that reside on the palatal/lingual side of the incisal edges of the denture and the central fossae of the posterior teeth. Due to the dimensional stability and strength of the SR Ivocap (Ivoclar Vivadent) acrylic, I’ve found that adding a metal mesh is no longer needed in most cases.6

The patient was given a drug protocol for surgery that included amoxicillin, Decadron, ibuprofen, and an alcohol-free chlorhexidine rinse (such as GUM Paroex Chlorhexidine Gluconate Oral Rinse USP, 0.12% [Sunstar Butler]).

Surgical Phase
The patient presented to our clinic, having taken the drug protocol as directed. The maxilla was anesthetized (4 carpules of 4% Septocaine [1:100,000 epinephrine]). The key to any case done under only local anesthetic is achieving profound anesthesia and, in addition, being able to maintain that level of local anesthesia for the entire duration of the procedure. A crestal incision was made from tuberosity to tuberosity, and then all remaining teeth were removed. Based upon the CBCT scan and the prosthetic plan, an alveoloplasty was done to a predetermined height on the ridge. A clear, duplicate maxillary denture was then placed in the mouth, and the pilot holes for the implants were prepared through the created opening of the denture to ensure that the screw access openings were in the appropriate positions. If the implant angle does not allow for screw access through these sites, then the use of a multi-unit abutment would be required to bring them into position; these come in either 17° or 30° corrections. The prosthetic plan called for 6 dental implants (Tapered Internal Plus [BioHorizons]) to be placed. All achieved at least 40 Ncm in initial stability, and all were able to be placed using straight multi-unit abutments at 30 Ncm in torque. The healing caps were placed, and then the arch was sutured with polyglycolic acid (PGA) sutures. It was at this time that the lower arch was anesthetized using a combination of lidocaine, mepivacaine, and Septocaine (Septodont). Also at this time, 3 carpules of Marcaine were administered in the maxillary arch to help maintain profound anesthesia there.

Figure 8. The mandibular arch, with multi-unit abutments in place. Figure 9. The maxillary arch, with multi-unit abutments in place.
Figure 10. The maxillary arch, with open-tray impression copings on the multi-units. Figure 11. The mandibular arch, with open-tray impression copings on the multi-units.
Figure 12. The mandibular
open-tray impression of the impression copings on the multi-unit abutments.
Figure 13. The retracted view of the PMMA prosthetic try-in, for the evaluation of the occlusion, midline, and gingival levels.
Figure 14. The full-face view of the PMMA prostheses at try-in, for the evaluation of the incisal edge positions of teeth Nos. 8 and 9 and the overall facial aesthetics. Figure 15. ProSmiles Dental Studio owner, Nick Herbert, hand-stacking pink gingival porcelain on the maxillary arch. Many of these cases can take 10 to 15 hours of craftsmanship to produce
high-end aesthetic outcomes.

Next, a thin layer of Blu-Mousse Classic (Parkell) was applied to the intaglio surface of the upper denture and placed in the mouth. This step allows the laboratory technician to see where the multi-unit abutments are and to create holes for the titanium cylinders to emerge from the multi-units. Titanium copings were seated on the multi-units, and then a small square of rubber dam material was placed over each cylinder and the access openings were sealed with a vinyl polysiloxane (VPS) impression material (Henry Schein). The denture was seated over these cylinders so that the fit against the palate was passive, and then the upper denture was luted to the cylinders using a pick-up material (SECURE Hard Pick-Up Material [3M]).7

While the onsite technician was working on the upper denture, the tissue on the lower arch was reflected and all the remaining teeth were removed. Appropriate alveoloplasty was done, and the clear lower denture was seated and used as the pilot drill guide to ensure proper screw-access position. Again, 6 dental implants (Tapered Internal Plus) were placed in positions that did not require the use of angle correction multi-units; only straight multi-units were used. The lower denture was lined with the Blu-Mousse Classic and given to the dental laboratory technician to create access while the upper converted denture was seated.8 The upper converted denture must be passive on the multi-unit abutments; the screws were torqued to 30 Ncm, and the access openings were sealed with VPS impression material.

Figure 16. The finished mandibular
monolithic full-arch zirconia restoration with hand-stacked pink gingival porcelain.
Figure 17. The intaglio surface of the
mandibular full-arch zirconia restoration.
Figure 18. The occlusal view of the mandibular full-arch zirconia restoration, showing the screw-access points located on the inside of the incisal edges of the anterior teeth and in the central fossae of the posterior teeth. Figure 19. The finished upper and lower full-arch zirconia restorations, ready for seating.

Next, the lower denture was picked up on the lower cylinders with the patient sitting up in the chair and in occlusion. The lower denture was then removed from the mouth and given to the lab technician to finish the conversion and to be polished. It was at this time that Marcaine was administered in the mandible to maintain anesthesia. The lower converted denture was seated and torqued, and the accesses was sealed (Figure 6). Occlusion and functional excursive movements were observed and adjusted to allow for bilateral simultaneous contact. A postoperative CBCT scan was taken (Figure 7).

Finally, the patient was given oral hygiene instructions and issued a Hydro Floss Oral Irrigator unit (Hydro Floss), along with a written booklet containing the post-op instructions. She was scheduled for a follow-up appointment in 2 weeks. (Note: I always call the patient the next day to find out how they are doing. This really helps to further build the doctor-patient relationship and creates another raving fan of the practice!)

Figure 20. The retracted view of the seated upper and lower full-arch zirconia restorations.
Figure 21. The patient’s full-face view, showing the final aesthetic outcome and her highest smile line.

As scheduled, the patient was seen again at 2 weeks post-op. The treatment prostheses were removed from the multi-units, the sutures were removed, and all areas were cleaned. After this appointment, the patient was seen 2 weeks later for a quick check of any symptoms, tissue health, and occlusion, then scheduled 3 months out for impressions.

Final Prosthetic Phase
At 3.5 to 4 months post-op, the patient returned for another CBCT scan and periapical (PA) radiographs (DEXIS X-ray Sensor ) of the implants to begin the assessment of integration prior to taking the final impressions. With the converted dentures off (Figures 8 and 9), open-tray impression copings were seated on the multi-unit abutments (Figures 10 and 11) and the final impressions were taken using implant impression trays (Miratray Implant Advanced Impression Tray [Hager Worldwide]) and a medium-bodied VPS (Henry Schein) impression material (Figure 12). Once the upper and lower impressions were taken, the healing caps were again placed on the abutments. Then a putty bite was taken to relate the 2 arches, as well as to mark the midline and the canine and incisal edge positions. The converted dentures were reseated, and the records were sent to ProSmiles Dental Studio (Rapid City, SD) for fabrication of PMMA full-arch prostheses for the try-in appointment set for 2 weeks later.

Figure 22. The post-prosthetic delivery CBCT scan, showing the upper and lower full-arch zirconia restorations in place. Figure 23. A periapical radiograph (DEXIS X-ray Sensor), showing that all the components were fully seated and providing a baseline image for the crest of bone around each implant.

When the patient returned a couple of weeks later, the converted dentures were again removed and the PMMA full-arch prostheses were seated (Figure 13). It is at this time that you must be aware of the need for passive fit of the restorations and to evaluate the facial aesthetics (the position of teeth Nos. 8 and 9 facially, gingival display, etc.) and occlusion (Figure 14). If no adjustments are needed, I will let the patient wear these prostheses for 2 to 4 weeks prior to making the final all-zirconia prostheses. If adjustments need to be made, I will make them to only one of the arches, if possible; mark the areas adjusted; and then remove and send them back to the laboratory, almost always with a new bite registration. If there is a problem with a cant or a large open bite, I will take a new Kois face-bow transfer and a bite record and ask for another PMMA try-in.

In this case, there were no adjustments needed to the PMMA prostheses, so the patient was allowed to wear them home and the mounted casts were sent back to the lab team for fabrication of the upper and lower full-arch (solid) zirconia restorations. From purely an aesthetic standpoint, it is my opinion that hand-stacked gingival shaded porcelain is far superior to that of (pink) stained zirconia (Figures 15 to 19).

When the final zirconia prostheses were returned from the laboratory team at the delivery appointment, they were first checked for passive fit on the multi-unit abutments. Once passive fit was verified, the occlusion and excursions were checked. Then the prosthetic screws were torqued to 30 Ncm, Teflon tape was placed over each hex, and the accesses were sealed with bonded composite resin9 (Figures 20 and 21). A post-prosthetic CBCT scan and PA radiographs (Figures 22 and 23) were taken. Finally, the patient was scheduled for an additional follow-up appointment one week later.

Maintenance Appointments
In our office, we schedule patients for a check-up appointment at 6 months post-delivery of the final prostheses. At this appointment, the occlusion and excursions are checked again, the prostheses are examined for any signs of wear, and the prostheses are removed to check the torque of the abutments and to evaluate the health of the soft tissues. The prostheses are then cleaned and reseated with new prosthetic screws. In addition, home care is reviewed again.

The next appointment is 6 months later (at one-year post-prosthetic delivery), at which PA radiographs will be taken. Unless there is an issue, the prostheses will not be removed again. Proper home care is emphasized, and patients are instructed to continue with the regular use of the Hydro Floss Oral Irrigator unit and toothbrush.10

CLOSING COMMENTS
The treatment of a terminal dentition, as it relates to the needs and desires of the patient, must align with the clinicians’ beliefs and skillsets. Having a well-trained dental office team who believes in the abilities of the treating dentist, as well as a thoughtful patient-centered treatment plan is vital to making cases, like the one presented in this article, a reality. Furthermore, finding and working with a skilled and dedicated dental laboratory team that understands this workflow is imperative for clinical efficiency, patient satisfaction, and ultimately, the success of any practice.

Acknowledgment
Dr. Moody wishes to express his heartfelt gratitude to the entire dental laboratory team at ProSmiles Dental Studio in Rapid City, SD.


References

  1. Chideka K, Klass C, Dunne S, et al. Listening to older adults: community consultation on a new dental service. Community Dent Health. 2015;32:231-236.
  2. Tischler M, Patch C. The Dental Turning Point for Baby Boomers. Austin, TX: Lioncrest Publishing; 2018.
  3. Winerman L. ‘Thin slices’ of life. Monitor on Psychology. 2005;36:54.
  4. Tischler M, Patch C, Bidra AS. Rehabilitation of edentulous jaws with zirconia complete-arch fixed implant-supported prostheses: an up to 4-year retrospective clinical study. J Prosthet Dent. 2018 Mar 17. [Epub ahead of print]
  5. Tak On T, Kois JC. Digital smile design meets the dento-facial analyzer: optimizing esthetics while preserving tooth structure. Compend Contin Educ Dent. 2016;37:46-50.
  6. Gharechahi J, Asadzadeh N, Shahabian F, et al. Dimensional changes of acrylic resin denture bases: conventional versus injection-molding technique. J Dent (Tehran). 2014;11:398-405.
  7. Moghadam M, Iyer S. Conversion prosthesis: fabricating chairside immediate complete denture. N Y State Dent J. 2011;77:28-29.
  8. Misch CM. Immediate loading of definitive implants in the edentulous mandible using a fixed provisional prosthesis: the denture conversion technique. J Oral Maxillofac Surg. 2004;62(9 suppl 2):106-115.
  9. Abdulmajeed AA, Lim KG, Närhi TO, et al. Complete-arch implant-supported monolithic zirconia fixed dental prostheses: a systematic review. J Prosthet Dent. 2016;115:672-677.
  10. Bidra AS, Daubert DM, Garcia LT, et al. Clinical practice guidelines for recall and maintenance of patients with tooth-borne and implant-borne dental restorations. J Prosthodont. 2016;25(suppl 1):S32-S40.

Dr. Moody, a graduate of the University of Oklahoma College of Dentistry, maintains a private practice in Rapid City, SD, where he has limited his practice to dental implant services. He is a Diplomate of the American Board of Oral Implantology; a Fellow and Associate Fellow with the American Academy of Implant Dentistry; and a Diplomate, Master, and Fellow with the International Congress of Oral Implantologists. Dr. Moody is an adjunct professor at the University of Nebraska Medical College and is a Mentor at the Kois Center in Seattle. Dr. Moody is a regular contributing author for Dentistry Today and is listed as one of Dentistry Today’s Leaders in CE. He is also an Advisory Board Member for the publication’s Implants Today section. In addition, he is the founder of Implant Pathway, one of the nation’s leading Implant CE providers. He can be reached via email at justin@justinmoodydds.com.

Disclosure: Dr. Moody is a paid consultant for BioHorizons Dental Implant Systems and a partner and consultant for ProSmiles Dental Studio.

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