A Partially Analog Approach by Dr. Emil M. Verban Jr.

A Partially Analog Approach 

Creating a fantastic implant-supported denture without the full digital suite


by Dr. Emil M. Verban Jr.


In my 46 years of practicing dentistry, no branch of dentistry has undergone such a significant change as implant dentistry.

In the late 1970s, teeth were extracted and the bone was allowed to heal for six months before implants were placed, then buried and allowed to heal for another six months before uncovering and loading. Today, with changes in digital technology, implant surfaces, drilling protocols and thread design, teeth can be extracted and implants can be placed and even loaded the same day.

Some studies have shown that digital treatment can be as successful as analog and reduce both time and cost of treatment. For single units or small bridges, I think the result will be the same, but I have reservations about the precision of digital methods for large prostheses and thus prefer an analog approach for them. The questions for me, after 30 years of implant experience, are if the newer technology is a necessity for excellent outcomes and if the cost of implementation is justified. Digital dentistry can be alluring, but we should keep in mind that the outcome is what matters most.


Most patients prefer implant-supported dentures

A review of the literature indicates that when compared with traditional dentures, implant-supported prostheses significantly improved the life of edentulous patients. From the patient perspective, two things have remained the same: A certain number of patients don’t want to wear removable dentures either during or at the end of treatment. This perspective has resulted in pushing the envelope, which results in patients having teeth removed and implants placed and receiving fixed implant-supported restorations the same day.

Today, we see an increasing number of patients whose dentition is terminal. Clinical treatments have involved maintaining nonrestorable teeth for as long as possible. Maintaining a terminal dentition has consequences on the bone and the fear of edentulism has forced many patients to ignore failing oral conditions. With tooth loss, changes occur over time, which leads to variability among those seeking full-arch maxillary implant-supported restorations. Careful treatment planning before implant placement is critical to determine which restorative option is best.

Key factors must be evaluated to determine which prosthetic design is used for optimal success. These include quantity and quality of bone, lip line, lip support and aesthetic demands. Prosthetic space should be evaluated before implant placement; lack of space can lead to increased rate of prosthetic failure through weak prosthetic substructure.

With minimal bone resorption, conventional crowns and bridgework on implants are feasible. With moderate resorption, there is missing hard and soft tissue; these patients require a prosthetic replacement with white as well as pink. When there’s a large discrepancy between implant position and the position of teeth for lip support, a prosthesis with contours is not conducive to good oral hygiene results. To establish good contours, bone reduction will be required to place implants more apically.


Case study

A 36-year-old patient with a history of tooth loss (Fig. 1) presented with pain. To address her chief complaint, I extracted Teeth #1, 2, 15 and 18, which then allowed for discussion of options for further treatment. Another appointment was scheduled for models (Fig. 2) and the CBCT imaging (Fig. 3) required for evaluation of the key factors mentioned above. After options were discussed, the patient decided on an all-on-X maxillary approach. (For budgetary reasons, her mandibular arch will be treated in the future, with a plan to place implants in #19 and 20 and crown #29 and 30.)

Implant Guided Prosthesis
FIG. 1
Implant Guided Prosthesis
FIG. 2
Implant Guided Prosthesis
FIG. 3

The models were mounted and the midline, vertical and the restorative space were marked (Fig. 4). Gingival margins also were marked before any teeth were removed. The model reduction and denture setup were completed, and a denture was fabricated for pickup the day of surgery (Fig. 5). A duplicate clear resin version (Fig. 6) also was made, to be used as a surgical guide and to evaluate restorative space. Windows were cut in the clear guide 5–6 mm from the position of the prosthetic-free gingival margin.

Implant Guided Prosthesis
FIG. 4
Implant Guided Prosthesis
FIG. 5
Implant Guided Prosthesis
FIG. 6


After the anterior teeth were extracted, I used the clear resin guide to evaluate restorative space and determined that a slight bone reduction would be required. Four Anyridge implants were placed, with 15-degree multiunit abutments (MUAs) in the anterior and 30-degree MUAs in the posterior. (I have found the thread design of Anyridge implants is very beneficial in establishing sufficient primary stability for immediate-loading protheses.) For closure, 5-0 chromic gut was used.

Temporary healing caps were placed and the denture lined, with bite registration to indicate where screw access holes needed to be made in the denture. Holes were drilled, temporary caps removed and a temporary titanium abutment placed to be picked up with the denture. The two anterior abutments were picked up first, and the palate was used to stabilize and position the provisional for incisal edge position before the palate was removed and the two posterior abutments were picked up.

The provisional was removed, its voids filled, and it was trimmed and polished (Figs. 7–11). The patient was given dietary restrictions and hygiene instruction, then dismissed with the provisional.

Implant Guided Prosthesis
FIG. 7
Implant Guided Prosthesis
FIG. 8
Implant Guided Prosthesis
FIG. 9
Implant Guided Prosthesis
FIG. 10
Implant Guided Prosthesis
FIG.11


After four months, the provisional was removed and an open-tray impression taken. Ligature wire (Fig. 12) between the impression coping with light-cured composite was added for ridged fixation of the copings (Fig. 13). From this impression, the master model was created.

Implant Guided Prosthesis
FIG. 12
Implant Guided Prosthesis
FIG.13


At the patient’s next appointment, the provisional was removed and placed on the master model for verification. The provisional seated perfectly, verifying the accuracy of the impression. The model with the provisional was used to mount against a lower model for the VDO centric bite (Figs. 14 and 15: I did not have a photo of my provisional, but instead used a copy of the provisional used for bar fabrication). After mounting, the provisional was then seated back into the patient’s mouth, and she was dismissed.

Implant Guided Prosthesis
FIG. 14
Implant Guided Prosthesis
FIG.15


At this point, I had a verified model mounted from which I could have a milled chrome cobalt bar fabricated. But to have the bar milled, I needed to provide a desired final setup that could be scanned and cut back.

In this case, I had a model of my denture setup, so I made a coping, filled it with resin and created a duplicate of my provisional. This was secured on my mounted master model with one titanium abutment and sent to Preat to design the bar. (A shout-out to Jeff for his design, Fig. 16)

Implant Guided Prosthesis
FIG. 16


I only needed to send the master model with the duplicated provision for bar construction. Exocad software was used to scan the model and setup and design the bar (Figs. 17–20). The design was sent for approval and the order was placed to mill the bar.
Implant Guided Prosthesis
FIG. 17
Implant Guided Prosthesis
FIG. 18
Implant Guided Prosthesis
FIG. 19
Implant Guided Prosthesis
FIG. 20


The bar was tried in (Fig. 21) to evaluate fit, then sent to Hiro along with a photo of the bar with midline and cant of maxilla (Fig. 22) to aid in addition of porcelain (Fig. 23). It is critical for long-term success to have a prothesis that allows for easy cleaning.

Implant Guided Prosthesis
FIG. 21
Implant Guided Prosthesis
FIG. 22
Implant Guided Prosthesis
FIG. 23


The final prothesis is seen in Figs. 24–28.
Implant Guided Prosthesis
FIG. 24
Implant Guided Prosthesis
FIG. 25
Implant Guided Prosthesis
FIG. 26
Implant Guided Prosthesis
FIG. 27
Implant Guided Prosthesis
FIG. 28

In conclusion, an analog approach can produce an aesthetic and functional full-arch prothesis, if key factors are evaluated and there is attention to detail.

Author Bio
Dr. Emil M. Verban Jr. Dr. Emil M. Verban Jr. earned his DDS from Loyola University School of Dentistry. He practices general dentistry full time in Bloomington, Illinois, with a special interest in cosmetic and implant dentistry. Verban is a nationally recognized leader, lecturer and educator in implant dentistry, and has developed and patented surgical products that increase safety and precision for implant surgery. He is a member of the American Dental Association, the Academy of General Dentistry, the International Team of Implantology and the American Academy of Implant Dentistry.
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