Phased Implant-Supported Full-Mouth Dentures

Figure 1. The preoperative retracted view of the patient’s anterior maxillary and mandibular teeth.

INTRODUCTION
Dental implants enable dentists to provide edentulous patients with more stable and secure full-arch overdentures.^1-3 Compared to conventional removable dentures, implant-retained overdentures allow edentulous individuals to enjoy many benefits, including a more comfortable and confident ability to eat the foods they love, better nutritional intake, improved self-confidence and self-esteem, and a more youthful facial appearance.^4,5

Of paramount importance to meeting a patient’s expectations for implant overdenture treatment is a thorough and accurate diagnosis, comprehensive treatment planning, and envisioning the final outcome before initiating any procedures (eg, extractions, grafting, implant placement, or overdenture attachment).^6-8 The appropriateness of any proposed treatment is predicated on the evaluation and assessment of the patient’s condition and characteristics. The patient’s needs, concerns, and desires are also important; these are valuable when planning treatment and should be addressed during the consultation and examination appointments. For example, when a patient who truly needs maxillary and mandibular overdentures presents, simultaneously planning and providing the options to him or her would be preferred in order to control occlusion and other treatment aspects.

Unfortunately, despite the comprehensiveness of dental implant treatment plans, many individuals still decline this option. Reasons may include finances, time constraints, and/or compliance concerns. Other factors may include healing times, multiple appointments, chair time, and other perceived inconveniences. However, if and when a patient is unable to undergo treatment according to the dentist’s ideal plan, determining a way to extend and/or sequence the requisite procedures and prostheses while establishing proper occlusion is of paramount importance.

Impact of Digital Technologies
Interestingly, digital-based technologies, techniques, and materials are transforming the way dentists plan and execute implant-retained overdenture treatments, including those involving multiple extractions and implants on both arches. Intraoral impression scanning, digital wax-ups and restoration design, implant-planning software, and in-office CAM milling or 3-D laboratory printing—among other technologies—provide the means to sequence, phase, perform, and complete implant treatments more predictably, efficiently, and cost-effectively.^9,10

Figure 2. Teeth Nos. 8 to 10 were extracted, followed by immediate bone grafting.	Figure 3. With the Snap-On Smile (DenMat) in place, implant placement planning for the lower jaw could commence.

Figures 4a and 4b. A combination of CBCT images (CS 9300 [Carestream Dental]) and image files created prior to the maxillary tooth extraction were used with planning software (coDiagnostiX Implant Planning Software [Dental Wings]) to determine mandibular implant placement. Implant position was designed to maximize the anterior-posterior spread.

For example, 3-D cone-beam computed tomography (CBCT) enables dentists to precisely determine the ideal location and angulation for implant placement, as well as the appropriate implant size, length, and diameter. When these scans are combined with other digital image files, computer-aided design (CAD) software can then be used in conjunction with implant-planning software and computer-assisted manufacturing (CAM) to fabricate precision surgical guides for accurate implant placement. These same CAD/CAM technologies can be exploited to streamline the processes involved with the design and fabrication of provisional, removable, and full-arch implant-retained overdentures.

Digital Dentures
In particular, digital dentures (Pala Digital Dentures [Kulzer]) that are created using CAD/CAM and 3-D printing eliminate the inefficiencies (eg, long and multiple appointments), challenges (eg, a porous composition prone to staining and odor or an unaesthetic tooth shape or arrangement), and inaccuracies (eg, poor fit or improper occlusal schemes) typical of conventional denture procedures.^11,12 The records required to design and fabricate a patient’s dentures are captured digitally during one appointment and, because they are stored electronically, can be applied as appropriate to future denture design and fabrication processes (eg, a spare or replacement denture).¹³

Figure 6. Potential abutments for the prosthesis were evaluated, including temporary sleeves on multi-unit abutments (2 in the center) (Performance Implant [OsteoReady]) and fixed detachable LOCATOR abutments (on the far left and far right) (LOCATOR F-Tx [Zest Dental Solutions]).	Figure 7. A view of the surgical guide pinned into place, revealing the position of the implants.
Figure 8. The fixed LOCATOR abutments (LOCATOR F-Tx) were immediately placed.	Figure 9. The provisional PMMA digital denture was tried in the mouth over the pinned guide.

By incorporating digital records and processes into the implant and overdenture treatment processes, an extended full-arch overdenture treatment plan can usually be developed and completed with less chair time, fewer appointments, and less frustration. The case presented in this article demonstrates the unique manner in which an extended treatment plan was developed and executed for a patient who required extractions, implants, and overdentures in both arches using digital technologies and digitally fabricated prostheses.

CASE REPORT
A 71-year-old man presented with swelling, infection, and pain in his anterior maxillary and mandibular teeth, leaving him unable to bite or chew (Figure 1). He and his wife were planning a period of extended travel, and she wanted him to be able to smile in photographs; this was the real motivating factor behind the patient seeking treatment at this time.

A thorough clinical examination was performed, during which digital photographs (EyeSpecial C-III [Shofu Dental] and Canon EOS 80D [Canon USA]), intraoral impression scans (CS 3600 [Carestream Dental]), and CBCT images (CS 9300 [Carestream Dental]) were obtained. Conventional impressions were also taken (Status Blue [DMG America]) in addition to a facebow transfer and centric relation bite registration.

Maxillary Provisionalization
In addition to his upcoming travel, other issues and considerations for this patient that affected treatment planning included his finances. Therefore, an extended and comprehensive phased treatment plan that envisioned the ultimate prosthetic outcome was developed, beginning with a virtual wax-up of the maxillary and mandibular arches.

Figure 10. Allograft bone graft material (BaseBone) was placed in the extraction sockets.	Figure 11. The tissue was sutured, and then the selected abutments were placed and blocked out.

Figure 13. A view of the denture attachment housings and black processing balls in the overdenture. The black processing balls were replaced with protective polishing caps.	Figure 14. A view of the mandibular PMMA provisional overdenture in the patient’s mouth.

Figure 15. A post-implant (OsteoReady) placement panoramic radiograph was taken.

It was determined that the severely compromised maxillary teeth that were causing him the most pain (teeth Nos. 8 to 10) would be extracted first and would include the placement of grafts (Figure 2). A removable smile prosthetic (Snap-On Smile [DenMat]) based on the virtual wax-up would be inserted to allow sufficient healing time in the maxillary arch to support subsequent implant placement and then restoration with a full-arch denture. The immediate use of this removable prosthetic would also help to extend the treatment plan while simultaneously enabling proper occlusion to be built into the mandibular arch.

The virtual wax-up helped to determine where the prosthetic teeth should be positioned in the removable provisional smile restoration (Snap-On Smile) (Figure 3). With the Snap-On Smile in place, implant placement planning and digital denture design for the lower jaw commenced.

Immediate Mandibular Implant Placement and Provisionalization
A combination of CBCT images (CS 9300) and image files created prior to the maxillary tooth extraction were then used with planning software (coDiagnostiX Implant Planning Software [Dental Wings]) to determine mandibular implant placement. Implant position was designed to maximize anterior/posterior spread (Figure 4). Because bone reduction would be required, a stackable bone reduction guide and pilot guides were constructed (Implant Concierge) and tried on a stereolithic model. A provisional polymethyl methacrylate (PMMA) acrylic digital denture was also constructed and tried on the stackable guide to confirm fit (Figure 5).

Potential abutments for the prosthesis were evaluated, including temporary sleeves on multi-unit abutments (Implant Solutions [OsteoReady]) and fixed detachable LOCATOR abutments (LOCATOR F-Tx [Zest Dental Solutions]) (Figure 6). This spherical attachment system—which is indicated for use with fixed, dentist-only removable partial and full-arch restorations on endosseous dental implants—was selected for several reasons.

=

Figure 17. A lingual view of the prosthesis, showing the CAD/CAM titanium frame with acrylic material.	Figure 18. The final LOCATOR F-Tx high retention balls were seated in the prosthesis.

First, using LOCATOR attachments represents a more cost-effective option compared to other alternatives.14 Considering this patient’s financial concerns, this was a significant benefit. Additionally, the LOCATOR F-Tx abutments accommodate a 20° divergence, which would be necessary in this case due to the angled placement of implants at site Nos. 26 and 28 and the need to ensure a secure yet passive fit at those positions.15,16 Finally, LOCATOR attachments require only efficient, simple, and cost-effective chairside processing of the overdenture, which further decreases the treatment costs associated with laboratory fees, in addition to reducing chair time and the number of appointments necessary.^14,17

All mandibular teeth were extracted, the bone reduction guide was pinned in, and an alveoplasty was performed. The pilot guide was pinned into place, after which the implants were placed (Figure 7). In particular, 3.75 mm x 13 mm coated, root-form implants (Performance Implant [OsteoReady]) were placed in site Nos. 21, 24, 26, and 28 (site Nos. 26 and 28, specifically, had 20° angles). Fortunately, the spherical attachment geometry allowed pivoting of the denture attachment housing in any direction on the angled implants,18,19 which would help in avoiding the alveolar nerve and ensuring as much anterior/posterior spread as possible.

Once the selected fixed LOCATOR attachments were torqued into place using a dedicated abutment driver (LOCATOR F-Tx Abutment Drivers [Zest Dental Solutions]) (Figure 8), the provisional PMMA digital denture was tried in the mouth and onto the abutments directly over the pinned guide (Figure 9). After confirming its fit, the PMMA provisional denture was removed, at which time an allograft bone graft material (BaseBone) was placed in the extraction sockets (Figure 10). The tissue was then sutured with microsutures to achieve primary closure.

Figure 20. The prosthesis was seated using the LOCATOR F-Tx seating tool (Zest Dental Solutions).	Figure 21. A view of the definitive lower fixed prosthesis seated in the mouth.

Next, the denture attachment housings and block out spacers were placed onto the LOCATOR F-Tx abutments and positioned at the correct angle (Figure 11). Characteristics of these attachment housings include aggressive grooves and flats that are picked up during the chairside processing procedure, as well as internal threads that accept PEEK retention balls and processing balls that simply snap into the abutment(s). Combined, these attributes contribute to significantly simplified techniques for preparing overdentures for secure retention with implants.²⁰

A dual-/light-cured syringeable acrylic material was then placed into the underside of the provisional PMMA overdenture base and onto the denture attachment housing for use in picking up the black processing balls. The overdenture was seated in the patient’s mouth and onto the abutments. The patient closed into light occlusion while the acrylic material set, after which the overdenture was removed by disengaging the black processing balls in the denture attachment housings that were picked up in the acrylic (Figure 12).

A hand driver was used to remove the black processing balls, which were replaced with protective polishing caps by using a dedicated retention ball hex driver. Acrylic material was placed around the denture attachment housing wherever any voids were present and then light cured. To create a smooth finish on the overdenture and remove any excess material, a chairside polishing bur was used, after which the polishing caps were removed. The dedicated retention ball hex driver was then used again to place high retention green ball attachments into the overdenture (Figure 13). The PMMA provisional overdenture was then placed in the patient’s mouth. In particular, the LOCATOR F-Tx attachments were engaged with the LOCATOR abutments to seat the provisional denture on the implants (Figure 14). A post-implant placement panoramic radiograph was taken (Figure 15). The patient was dismissed, appointed for a follow up, and allowed to heal while traveling.

Definitive Mandibular Denture
When the patient was financially ready to proceed with the treatment plan, closed-tray abutment level impression copings were seated, and an abutment level impression was made using a vinyl polysiloxane (VPS) impression material (Honigum Pro [DMG America]) (Figure 16). His lower final prosthesis (Pala Digital Dentures) was digitally designed with an occlusal scheme consistent with the maxillary removable provisional (Snap-On Smile). For the definitive overdenture, the decision was made to combine digital denture teeth (Pala Digital Dentures) with a titanium denture base framework (Figure 17). The framework would be processed chairside to accommodate the selected abutment attachment system (LOCATOR F-Tx) (Figure 18).

The dental laboratory team created a virtual wax-up and set and moved the proposed denture teeth according to that wax-up, and then proceeded to facilitate the CAM fabrication of the final mandibular overdenture. This meant only one patient appointment was necessary prior to delivery of the final implant overdenture, compared to the 5 or more appointments typically required for conventional dentures. At the delivery appointment, the titanium framework of the digital denture was processed for the LOCATOR F-Tx attachment housings. Final LOCATOR F-Tx abutments were seated in prosthesis (Figure 19). The prosthesis was seated using the LOCATOR F-Tx seating tool (Zest Dental Solutions) (Figure 20). After seating the restoration, the patient was given hygiene instructions for proper maintenance and scheduled for a postoperative evaluation (Figure 21).

CLOSING COMMENTS
Providing an extended phase treatment plan based on a thorough diagnosis is often necessary in order to ensure that patients receive the high-quality, state-of-the-art care that is warranted. This typically requires addressing a patient’s most immediate needs first, weighing clinical decisions against patient constraints (eg, schedule and financial), and considering unique approaches to providing the components of a phased plan. In the future, the patient in this case will return for the extraction of his remaining maxillary teeth, the immediate placement of 6 implants, and immediate loading with a provisional PMMA digital denture attached with LOCATOR F-Tx abutments.

References

1. Vogel RC. Implant overdentures: a new standard of care for edentulous patients—current concepts and techniques. Compend Contin Educ Dent. 2008;29:270-276.
2. Little D, Apparicio TP. Aesthetic denture rehabilitation. Dent Today. 2012;31:120-123.
3. DiMatteo AM. Dentures & implants: bringing them together for a winning combination. Inside Dentistry. 2009;5:96-104.
4. Morais JA, Heydecke G, Pawliuk J, et al. The effects of mandibular two-implant overdentures on nutrition in elderly edentulous individuals. J Dent Res. 2003;82:53-58.
5. Heydecke G, Thomason JM, Lund JP, et al. The impact of conventional and implant supported prostheses on social and sexual activities in edentulous adults. Results from a randomized trial 2 months after treatment. J Dent. 2005;33:649-657.
6. Tischler M. Treatment planning implant dentistry: an overview for the general dentist. Gen Dent. 2010;58:368-374.
7. Hochwald D, Arcan S, Farnad F. The team approach: simplifying complex care. J Calif Dent Assoc. 2008;36:609-614.
8. Jivraj SA, Corrado P, Chee WW. An interdisciplinary approach to treatment planning in implant dentistry. J Calif Dent Assoc. 2005;33:293-300.
9. Junnila T. Growing your practice in a down economy. Northwest Dent. 2010;89:49-51.
10. Levin RP. How dentistry weathers a slow economy. J Am Dent Assoc. 2007;138:391-392.
11. Li W, Yuan F, Lv P, et al. Evaluation of the quantitative accuracy of 3D reconstruction of edentulous jaw models with jaw relation based on reference point system alignment. PLoS One. 2015;10:e0117320.
12. Infante L, Yilmaz B, McGlumphy E, et al. Fabricating complete dentures with CAD/CAM technology. J Prosthet Dent. 2014;111:351-355.
13. Bidra AS, Taylor TD, Agar JR. Computer-aided technology for fabricating complete dentures: systematic review of historical background, current status, and future perspectives. J Prosthet Dent. 2013;109:361-366.
14. Priest G. Efficient placement of implant overdenture attachments. Dent Today. 2011;30:58-62.
15. Ferrare N, Leite AF, Caracas HC, et al. Cone-beam computed tomography and microtomography for alveolar bone measurements. Surg Radiol Anat. 2013;35:495-502.
16. Van Assche N, van Steenberghe D, Guerrero ME, et al. Accuracy of implant placement based on pre-surgical planning of three-dimensional cone-beam images: a pilot study. J Clin Periodontol. 2007;34:816-821.
17. Strong SM. The spare implant overdenture: retrofitting an existing denture to Locator attachments. Gen Dent. 2011;59:20-22.
18. Wilson TG Jr. The positive relationship between excess cement and peri-implant disease: a prospective clinical endoscopic study. J Periodontol. 2009;80:1388-1392.
19. Linkevicius T, Puisys A, Vindasiute E, et al. Does residual cement around implant-supported restorations cause peri-implant disease? A retrospective case analysis. Clin Oral Implants Res. 2013;24:1179-1184.
20. Zou D, Wu Y, Huang W, et al. A 3-year prospective clinical study of telescopic crown, bar, and locator attachments for removable four implant-supported maxillary overdentures. Int J Prosthodont. 2013;26:566-573.

Dr. Little, a graduate of the University of Texas Health Science Center at San Antonio School of Dentistry (UTHSCSA-Dental), maintains a state-of-the-art multidisciplinary general practice in San Antonio. He is an accomplished national and international speaker, a professor at UTHSCSA-Dental, and an author. Dr. Little is also a respected clinical researcher, focusing on implants and dental materials, as well as a consultant on emerging restorative techniques and materials. He is a regular contributing author for Dentistry Today and is one of Dentistry Today’s Leaders in CE. He can be reached via email at
dlittledds@professionalsindentistry.com.

Disclosure: Dr. Little serves as clinical director of OsteoReady.

Related Articles

Using an Integrated Digital Approach to Treatment Planning

Aesthetic Denture Rehabilitation

Fixed Implant-Supported Solution for a Failing Dentition