The Use of the EastFlex Monodont® Bridge in
Potentially Long-Term Transitional Fixed Prosthodontics 

    One of the biggest professional challenges that dentists face on a daily basis is the balancing act between a patient’s desire for a fixed bridge (or an implant) to replace a missing tooth and the clinical and/or economic reality that may be significant enough to contraindicate “traditional” approaches to fixed prosthodontics–thus Monodont® technology (EastFlex® Corporation) was invented.
    There is little argument within the dental profession that, conditions permitting, fixed prosthodontics is preferred rather than removable appliances. The customization of a fixed appliance to suit each individual application and the level of clinical and laboratory skills needed to produce it is the primary factor that has kept this treatment option out of reach for an extra-ordinary number of patients.

THEORY
    The dentist must rethink the difference between “temporary” and “transitional.” All too often, these treatment modalities are assumed to be synonymous. In doing so, the dentist unwittingly limits the treatment options that are offered to the patient, especially to the patient for whom treatment options may already be limited by economic considerations.
     The Monodont® universal fixed bridge components (Dental Arts Laboratories, Inc. and EastFlex® are currently comarketing Monodont® technology) allow the dental laboratory to fabricate a cost-effective, structurally sound, esthetic, and fully functional fixed bridge appliance that can be used in a number of transitional applications–short or long term depending on the application. For the patient undergoing implant placement, the Monodont® bridge can effectively function as a short-term non-loading, tissue contouring, healing template. To relieve the patient of the burdens and discomfort of a flipper or an unreplaced missing tooth, the Monodont® bridge can be a long-term fixed solution.


Figure 1–The ideal preparation for the Monodont® bridge will "lock" the assembly into the undercuts (proximal view).


Figure 2–The incorrect divergent wall (inlay) preparation will subject the assembly to premature debonding (proximal view).


Figure 3–The stent was seated on the abutment teeth, and the base of the No. 38 inverted cone diamond was used to "spot" the preparation through the pilot hole in the laboratory fabricated preparation guide/pontic positioning stent.
Figure 4–The "scuff marks" were cut through the stent using the base of the No. 38 inverted cone diamond.


Figure 5 –The preparations were cut strictly from the proximal to ensure an adequate undercut and as conservative a preparation as possible.


Figure 6 –Conservative, deliberately undercut class III anterior retaining preparations.


Figure 7 –Ideal relationship between the patented Monodont® bridge bifid rententive talons and the undercuts in the retaining preparations. Note the unencumbered embrasures that will allow patients easy access for cleaning.


Figure 8 –The stent will be used a second time to position the Monodont® bridge assembly during the bonding procedures described in the text.


Figure 9 –The model, preparation guide/pontic positioning stent, the Monodont® bridge, and instructions as they would be delivered from the laboratory.

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 TREATMENT
    The signature of the Monodont® technique is the preparation for the retention being cut after the bridge has been fabricated in the laboratory. All of the anterior preparations for the Monodont® bridge are simple class III preparations with a deliberate undercut (Figures 1 and 2), lingual to the contact point; the posterior preparations are all class II boxes through the proximal marginal ridge. It is because of this uniformity in preparation size and location that the laboratory, which also has the luxury of unimpeded vantage points on a model, can predictably locate the preparations. The location f the preparations on the patient’s abutment teeth with be realized by using a multi-purpose stent fabricated by the laboratory. Stents are routinely used to locate penetration entry into bone for implant placement–arguably a much more invasive and technique sensitive procedure than cutting a couple of class II or class III preparations.
    The stent was placed on the abutment teeth, and the location was “spotted” through the holes in the stent using the base cutting surface of an undercut diamond bur (usually a No. 38 inverted cone)(Figures 3 and 4). After the locations were marked (scuffing the enamel is more than adequate), the remainder of the preparation must be cut strictly from the proximal (Figure 5). This ensured that the preparation was cut as conservatively as possible with a deliberate undercut. When cutting the preparation from the lingual or occlusal, the natural path of one’s hand (attached to a handpiece in this case) will almost always produce a larger than necessary preparation, usually without the desired degree of undercut. Undercut preparations are critical to the success of this treatment modality. Insufficient tooth structure having a preparation with adequate undercuts is a contraindication.
    After the preparations were cut (Figure 6), and the Monodont® bridge was successfully trial seated and fitted (Figure 7), the preparations were etched with the dentist’s material of choice. A small among of flowable composite was delivered into the most interior aspects of the preparations to ensure that the internal line angles as well as the bifid retentive talons of the Monodont® bridge were covered. The bridge was seated, and the stent was placed over the assembly and abutment teeth to position the bridge in exactly the same three-dimensional orientation in which it was fabricated on the model (Figure 8). The initial internal layer of flowable composite was light-cured from all aspects, “tacking” the bridge into the preparations. The stent was removed, and the remainder of the preparation was filled with a hybrid composite (dentist’s preference), then light-cured and polished in the usual manner. The use of self-cure or dual-cure additives is also up to the dentist. Group function is indicated for all applications, as it would be in any prosthetic case (Figure 9).

CONCLUSION
The Monodont® bridge can be considered the “fixed bridge of first choice, or the fixed bridge of last resort.” It is designed to be another tool in the dentist’s “toolbox.” Most dentists report receiving a fee equivalent to a single unit of porcelain-fused-to-metal plus the fee for the mesial and distal retaining composite surfaces, usually single surface in the anterior and two surface in the posterior with a delivery chair time ranging from 20 to 30 minutes.[1]

ACKNOWLEDGMENTS
The author of this article, Dr. Maris J. Lans, is co-inventor of Monodont® technology along with former classmate and life-long friend Dr. Daniel E. Purvis. Dr. Purvis owns and operates Indiana Dental Centers, of Indianapolis, Indiana. Dr. Lans is retired after 22 years of active practice and now devotes all of his time to hands-on training of dental laboratory technicians and presenting lectures and seminars to the dental profession throughout North America. All Monodont® Laboratory Fabrications used in this article are courtesy of Dental Arts Laboratories, Inc. Peoria, Illinois.

REFERENCE
[1] – Midwest Dental Evaluation Group–INTERFACE. Conservative single-tooth replacement options: the “spider” bridge and the EastFlex® bridge. 2001; 13(77)