Replacing Teeth and Tissue Using a Mini Bar

Have you ever had a patient need not only a small section of teeth replaced but also tissue volume? If you've been practicing dentistry long enough you've probably seen a patient like this and, if not, you will at some point in your career. Most likely you'll recommend one of three basic solutions:

1. Removable Partial Dentures: Removable partial dentures will fit the bill but are a far cry from natural teeth. The good news is, if your patient is willing to accept the downfalls and compromises of partials, only strong teeth are needed to hold the dentures in place.
2. Implants: They're the next best thing to natural teeth. However, despite many advantages to tooth- or tissue-born prosthetics, for implants to be successful and function properly, they require quality bone that is ideally located.
   

   Remember, implants are just like teeth when it comes to cleaning. If the patient cannot clean the implant(s) there will be problems. Also, if the patient is missing tissue it often needs to be replaced by grafting or with a prosthetic. If tissue is being replaced prosthetically and a fixed-implant solution is desired, cleaning often becomes an issue.

3. Fixed Partial Dentures: For this option to be successful there must be teeth strong enough to hold the prosthesis. Also, like the implant option, missing tissue often needs to be replaced with grafting or prosthetics, and just like with implants if tissue is replaced prosthetically, cleaning can become an issue.

But what if none of the above options is a solution? For example, what if a patient who will be missing all six maxillary anterior teeth and has a massive amount of missing tissue? Well, you can do what I did when I treated this kind of case.

Treatment planning

As you can see from the patient's full-face smile, it's far from esthetic. (Fig. 1)

She has multiple problems such as overjet and overbite issues, missing lateral incisors, and her centrals will be lost (Fig.2). What's not as obvious is she'll lose the canines because they're not in the bone.

These dental issues came about when she was hit by a car and her maxillary anterior teeth were displaced and, as best as we can tell, the anterior portion of her maxilla was damaged and/or driven posteriorly.

The maxillary centrals were placed where they are in the images above by an ENT physician at a trauma center and, because of her severe injuries, the focus was to save her life first and her teeth a distant second. Treating this kind of dental patient and achieving highly functional, cleansable, natural-looking esthetics was not going to be simple.

Early on the patient indicated she did not want removable partial dentures. Instead, implants and a tooth-supported, fixed-partial denture were considered; however, the tooth-supported, fixed-partial denture would have had a very long span and tissue was not in the right place for the pontics. Her lack of tissue also proved to be a problem for an implant-supported, fixed-partial denture as well.

But could we get enough tissue there? Initially, we thought it would be possible with ortho, grafting, and perhaps a maxillary advancement. After an interdisciplinary discussion with the orthodontist, oral surgeon, and the patient, the final plan did not include maxillary advancement because the orthodontist believed it wasn’t needed to achieve ideal occlusion for the existing teeth and the patient wanted to avoid surgery if possible.

Treatment begins

With this plan in place we pressed forward with a plan to extract a lower incisor and retract the lower anterior teeth to help with the overjet issue. We also planned to level the occlusal plane to help with the overbite.

Toward the end of the orthodontics, the patient was ready for the extraction of #6, #7, #8, and #11 with simultaneous grafting of the ridge to gain as much hard tissue as possible. Although there still was an overjet issue, the occlusal planes were improved (Fig. 3).

Upon healing it was evident the amount of bone and arch form were still less than ideal but were improved (Fig. 4).

On top of the lack of ideal bone position, despite plenty of bone volume, there was also a lack of soft tissue volume. Given all this, there were just two options left: Graft more hard and soft tissue to get what was needed or devise another restorative option to meet the patient's goals.

Knowing additional grafting could not be guaranteed to result in an optimal outcome, or even an acceptable outcome for that matter, the decision was made to move in the direction of the backup option, which was worked into the case since grafting outcomes sometimes fall short of treatment goals.

It was during the workup when we asked ourselves, “What if we could combine the stability and esthetics of a fixed restoration with the cleanability of a removable restoration?” In a sense, the solution was an implant-supported fixed-removable partial denture.

In a nutshell, it was a mini bar supported by three implants with a prosthetic attached to the bar in a removable, but very secure, fashion.

The planning of the implant positions involved myself, a surgeon (Dr. Robert Wood of Arizona Oral and Maxillofacial Surgeons), and a lab technician (Arian Deutsch of Deutsch Dental Arts).

Once all three of us were satisfied with implant positions, a surgical guide was fabricated, designed, and printed (Fig. 6).

In the final surgical photo (Fig. 10), the implants may seem too far from the premolars; however, this was the ideal distance as requested by the lab technician. Comparing Fig. 10 with Figs. 6, 7 and 8, the implants are exactly where they were planned to be.

Restoration

Once healed, the restorative process began with an initial impression to create a custom impression tray, as opposed to a stock tray, to predictably get the accuracy needed for a case like this. The impression for the custom tray was also taken with open tray implant transfers to create a verification jig. Next, was to take a final impression with the verification jig that was looted together (Fig. 11).

From the final impressions master casts and a record base, a wax-rim was created. Just like a denture, the wax-rim was tried in and adjusted with the midline marked.

The next step was a teeth in wax try-in.

Once the tooth position was verified, a zero-degree taper bar was designed in resin.

This design was then scanned into exocad for further planning and prosthetic design.

After this, the zero-degree bar was milled in titanium.

The next step was to create an electroformed gold sleeve to provide the retention for the prosthesis via friction.

Next came the superstructure for the prosthetic. In this case, the substructure was designed with ideal tooth preparations on it to finish the case with individual cemented ceramic crowns on it rather than denture teeth.

The final prosthesis was completed after the ceramic crowns were fabricated and cemented in the lab and the tissue layered on with resin.

The final step was to deliver the prosthesis with a bar that can be easily flossed and cleaned (Fig. 20). The access holes are closed with Teflon and Primopattern gel.

The final prosthesis had massive retention. It takes a lot of effort for the patient to remove it, which is exactly what we wanted.

The result was great, and all involved were very happy with what was achieved. Of course there were other options for this case, like a traditional removable partial; however, as discussed and why we eliminated it was the fact it would not have been as retentive or provided the same level of function.

When it comes to a fully fixed nonremovable implant solution this would have provided either an unesthetic solution or an uncleansable prosthesis due to a lack of the same lip support and gingival esthetics with a flange.

John R. Carson, D.D.S., is a member of Spear Visiting Faculty and a contributor to Spear Digest.