INTRODUCTION
Despite our best efforts, teeth may not last forever. Many factors can elicit tooth loss, such as poor hygiene and certain foods or medications, but the process of aging is the most persistent and inescapable means of jeopardizing dental health. For this reason, edentulous patients are ubiquitous and will remain so since there is always a generation creeping towards seniority. There are a few options to treat edentulism in today’s market: conventional dentures, All-on-4s, and the small-diameter implant-retained overdenture (SDIRO). Among all the dental prostheses, none are as undervalued as the overdenture.
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| Figure 1. Preoperative full-face photo. | Figure 10. The final portrait photo at one week post-delivery. |
Conventional dentures are the longstanding option and widely used. They are removable prostheses that are designed to be supported by mucosal tissue, and they have a somewhat bulky feel with a tendency to shift during mastication. An arch fitted for a conventional denture has no teeth remaining to stimulate the jawbone, making bone resorption over time unavoidable. This gradual shrinkage of bone begets a perpetual string of chairside adjustments aimed at addressing the changing landscape of the patient’s mouth for the lifetime of the denture. The main advantages of conventional dentures are their detachability and affordability; they are easy for the patient to clean on a daily basis and the least expensive option available to treat complete or partial edentulism. However, they are functionally disadvantageous when compared to their modern counterparts.
Secure Alternatives
In 1998, Dr. Paulo Malo successfully treated the first patient with the All-on-4 implant concept using Nobel Biocare implants. These screw-retained overdentures are vastly superior to their predecessors in terms of clinical performance. All-on-4s are fixed prosthetics that screw onto 4 strategically placed regular diameter implants per arch, providing a technique with a 2-pronged resolution to the drawbacks of conventional dentures. First, the stability achieved with an All-on-4 is so substantial that it effectively restores the patient’s ability to chew as if he or she had natural teeth. Second, the implants secured in the jawbone ensure active bone stimulation, which forestalls shrinkage. The downsides of All-on-4s are their immovability and price. Cleaning must be scheduled because only a dentist can unscrew the fixture for prophylactic maintenance. As for the cost, many patients can’t afford to entertain the idea of an All-on-4, much less actualize the fabrication of one.
SDIROs embody the best of both worlds, combining the affordability and removability of conventional dentures with the stability and bone incitation of All-on-4s.1 SDIROs are removable prosthetics that deftly “snap” on and off of strategically placed implants. The biggest motivator/demotivator for patients faced with teeth replacement is the different costs involved in these treatment options. On average, the cost per arch of SDIROs are about one third the cost of an All-on-4. The snapping function of the SDIROs lend them a “temporary permanence” that can provide patient removability as well as the stability to closely match that of an All-on-4. Not only is cleaning an easier feat, which is an especially appealing option for patients making the transition from conventional dentures, but chewing is also dramatically improved, as it is with All-on-4s. Because SDIROs depend on implant support, stimulation of the bone is achieved and will actively prevent bone loss.
It should be noted that there are many brands of small-diameter implants with various benefits and limitations given the clinical indications. Some small-diameter implants are meant to be used in the short term to allow for healing, while others, such as the ones in the following case study, are indicated for long-term use. The ideal setup for SDIROs comprises 6 implants on the upper arch vs 4 implants on the lower arch.2 Note that individual patient circumstances may justify a variety of differing implant placement layouts within each arch. Care should be taken to maximize the number of implants used in each arch; however, if a lesser number of implants are used per arch than considered ideal, care should be taken when fabricating the prosthesis to consider limiting cantilever distance past the most distal implant and to distribute the occlusal forces over the implant abutments with the use of an internal bar.3
CASE REPORT
A 53-year-old male presented with embarrassment and frustration after enduring years of tooth loss, gum disease, a severe gag reflex, and fear of the dentist (Figure 1).
This patient’s upcoming marriage was his motivation to seek solutions to a problem that he thought would confine him to a life without teeth. His oral condition was poor with grade 3+ mobility, no bone support on the upper and lower arches (Figures 2 and 3), and infection throughout his mouth. Due to his severe gag reflex, he was worried that he would have no other option but to go without teeth for the rest of his life. He was disappointed after discussing his primary desire for an All-on-4 prosthesis, which he hoped would be his salvation, only to find out that an All-on-4 could not be a consideration because he could not afford the costs involved in that treatment option. However, when given the option of an SDIRO and upon discussing its affordability, his eyes lit up. He was all in.
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| Figure 2. Pre-op photo of the upper arch. The patient presented with periodontal disease and poor bone support. | Figure 3. Pre-op photo of the lower arch. Periodontal disease and poor bone support involving this arch were also noted. |
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| Figure 4. A 3-D lower CT scan (SIMPLANT) was used for planning the placement of Zest Dental Solutions’ LODI Implants (2.9 mm x 14 mm). | Figure 5. A 3-D Upper CT scan (SIMPLANT) was used for planning the placement of LODI Implants (2.9 mm x 14 mm). |
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| Figure 6. Upper implants were placed with 2.5-mm LOCATOR attachments (Zest Dental Solutions) in place. | Figure 7. Lower implants were placed with 2.5-mm LOCATOR attachments in place. |
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| Figure 8. Placement of the LOCATOR gaskets (Zest Dental Solutions) in the denture housing was done using a special housing placement tool. | Figure 9. Upper final housings in place. (Note the no-palate design and the reduced buccal flange.) |
Clinical Protocol
After tooth removal, bone grafting, and a 6-month healing period with interim upper/lower dentures (DAL Dental Lab, Peoria, Ill), a CT scan (conescan.com) (Figures 4 and 5) was ordered. The resulting plan was to place 4 small-diameter (2.9 mm x 14 mm) implants (LODI [Zest Dental Solutions]) in the upper arch, and 4 small-diameter (2.9 mm x 14 mm) implants (LODI) in the lower arch.
After the placement of the implants, LOCATOR abutments (Zest Dental Solutions) were placed (Figures 6 and 7). Integration of the implants into the upper and lower jaws was followed for 2 months prior to the start of fabrication of the final prosthesis. During integration, space was made in the interim dentures to allow the locator abutments to move freely without touching the temporary denture. A soft reline material (Mucopren [Kettenbach LP]) was used to aid in the soft-tissue healing process and for stabilization of the interim dentures around the implant abutments, especially on the upper interim prosthesis due to the necessity for a severe reduction in the palatal area.
When ready, the final prosthesis was fabricated following the same guidelines for traditional complete dentures, with some modifications for the implant support.
The master impression was taken with impression copings (Zest Dental Solutions) in place on top of the implant locator abutments. When the impression was removed, the impression copings were locked inside the master impression, thus recording the location of the implants. An analog (Zest Dental Solutions) was sent to the laboratory team for model fabrication. Corresponding denture housings (Zest Dental Solutions) were also sent at this time to the lab team to attach these housings to the analog in the model. This is needed in the base plate and wax rim record so that space evaluation can be considered during the entire fabrication process.
Bite records were taken in the same manner as for conventional complete dentures; however, the lab team should have fabricated the housings into the base plate so that the clinician could confirm the housings are in the correct positions during the records appointment. The lab team was instructed to minimize cantilever in the posterior area.
Try-in was done (as with conventional complete dentures), taking into consideration all functional, cosmetic, and phonetic parameters. It is also important during the try-in to take note of the bite. Care should be taken to ensure a balanced bite to avoid breakage of the final dentures.
After try-in was accepted by the patient, the lab team was instructed to process and finish the upper prosthesis without a palate and with minimal buccal and labial flange and with minimal cantilever in the posterior area of the lower denture.
When the finished case was delivered to the dental office, minimal pressure gaskets (Zest Dental Solutions) were placed into the housings with a special gasket instrument (Zest Dental Solutions) (Figure 8). If more hold is needed for denture support, a stronger gasket can be changed out during the delivery procedure (Figure 9). In this case, for more security, a stronger gasket was desired by the patient.
On delivery day, the denture should be evaluated for a precision fit. In some cases, because the housing shifted during processing, it is necessary to remove one or more of the housings and pick it/them back up chairside for the denture housings to properly fit the implant locators. This is easily accomplished with Quick Up (VOCO America). It is also important that upon delivery, the occlusion be fastidiously checked for a balanced bite.
The patient was overjoyed with his new smile (Figure 10). After his one-week postoperative bite check, he started hugging everyone in the office and said it was the best thing he had ever spent money on. He went on to say that he would not have teeth now if it was not for us suggesting this overdenture. He concluded by crediting us for changing his life and stated that he had a new and positive outlook on the profession of dentistry.
CLOSING COMMENTS
As humans, we are creatures of habit, but as dentists, we should strive to be the opposite. Allowing pre-set standards to dictate our paths of treatment options and choices is an injustice to our patients and to us. Every clinician must endeavor to have a fully stocked arsenal of treatment options on hand to address any clinical situation that arises. A given clinical scenario may very well require implementation of the more traditional approach or the most popular solution, but the next time a patient seeks treatment for edentulism, do not be the clinician who overlooks and undervalues the overdenture.
References
- Martínez-Lage-Azorín JF, Segura-Andrés G, Faus-López J, et al. Rehabilitation with implant-supported overdentures in total edentulous patients: a review. J Clin Exp Dent. 2013;5:e267-e272.
- Raghoebar GM, Meijer HJ, Slot W, et al. A systematic review of implant-supported overdentures in the edentulous maxilla, compared to the mandible: how many implants? Eur J Oral Implantol. 2014;7(suppl 2):S191-S201.
- Luthra R, Sharma A, Kaur P. Implant supported overdenture: a case report. Periodontics and Prosthodontics. 2016;2:1-5.
Dr. Simos received his DDS degree at Chicago’s Loyola University. He maintains private practices in Bolingbrook and Ottawa, Ill. He is the founder and president of the Allstar Smiles Learning Center and client facility in Bolingbrook, where he teaches postgraduate courses on a variety of clinical topics, including cosmetic dentistry, occlusion, and comprehensive restorative dentistry. Dr. Simos is an internationally recognized lecturer and leader in cosmetic and restorative dentistry and is listed as one of Dentistry Today’s Leaders in Continuing Education. He can be reached via email at cmesmile50@gmail.com, via the website allstarsmiles.com, or via the Twitter handle @allstarlc1.
Disclosures: Dr. Simos reports no disclosures.
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