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ESSIX^TM TEMPORARY BRIDGES

Essix™ removable appliances snap into place and are retained, without clasps, by the natural undercuts gingival to the anterior contact point. These clear, thin cuspid-to-cuspid appliances are made from .030" Essix™ plastic sheets, which are reduced to .015" in thermoforming. Although Essix™ appliances are normally used as retainers¹ or for minor tooth movements, they can also be modified to serve as temporary anterior bridges.

It is sometimes necessary to incorporate anterior prostheses in the retainers of patients with congenitally missing lateral incisors or teeth lost due to trauma. The conventional method is to include a pontic in a Hawley-type framework, but such appliances are bulky and rather unaesthetic.

Essix™ technology provides a simpler, more efficient way to retain and replace missing anterior teeth. Exceptionally aesthetic temporary bridges can be fabricated quickly and inexpensively in the office.

TECHNIQUE 1. Obtain an accurate working cast of the anterior teeth. Place a separating medium in the edentulous alveolar ridge area (Fig.1).

Figure 1

2. Fit a pontic of appropriate size and color into the edentulous area. Trim the base of the pontic to approximate the edentulous alveolar ridge (Fig.2).

Figure 2

3. Cut a mesiodistal trench about 4mm wide and 3mm deep into the lingual surface of the pontic (Fig. 3).

Figure 3

4. Attach the pontic to the cast with quick-cure or light-cured acrylic. Pink acrylic can be used in the gingival area if desired. Do not use wax, which would melt in thermoforming.

5. With pontic in place, thermoform the Essix™ plastic sheet over the cast. The mesiodistal trench in the pontic will create a mechanical lock to the appliance (Fig. 4).

Figure 4

6. Trim the appliance with curved Mayo scissors as with an ordinary Essix™ retainer1 (Fig. 5).

PATIENT USE The Essix™ appliance is not only a prosthesis, but a retainer. To improve patient compliance with long-term retention², a duplicate appliance can be fabricated in a few minutes.

Because the pontic is held mechanically and not fused to the plastic, it can be popped out with a thin-bladed instrument (Fig. 6).

Figure 6

It is then replaced on the working cast, and another Essix™ bridge is thermoformed and trimmed as described above.

Both appliances are delivered to the patient, who will, of course, wear the one with the pontic (Fig.7). If the plastic becomes unduly worn, the patient can pop out the pontic and snap it into the spare framework. This demonstration should be given at the time of delivery.

Figure 7

We also give the working cast to the patient with instructions to keep it in a safe place. The patient is told that if both appliances should be lost or destroyed, the model can be brought to the office for immediate fabrication of a replacement.

Since an essix™ bridge will probably be worn while eating, it may wear faster than conventional Essix™ retainers, which are worn only at night. This kind of wear is usually localized in the cuspid region. The solution is to trim away the worn area with a scalpel. Ordinarily, the bridge will still be aesthetic and retentive.

The patient should be cautioned not to clean an Essix™ bridge with toothpaste, which dulls the brilliance of the plastic. Instead, a soapy cotton swab or the edge of a washcloth should be used.

The patient will usually be delighted with the stability, minimum bulk, and appearance of the appliances. For obvious reasons, the bridge is likely to be worn all day. Therefore, it may be advisable to reverse the usual retention protocol and have the patient leave the appliance out at night.

CASE REPORTS CASE 1. A patient with a congenitally missing upper right lateral incisor had been wearing an upper Hawley retainer with a pontic for two years after removal of fixed appliances. The retentive ball clasp of the retainer opened a 2mm space between the upper right second bicuspid and first molar (Fig. 8, Case 1A), and the patient was also concerned about a loose fit. An Essix™ bridge was fabricated (Fig. 8, Case 1B) with little, if any, disruption of the buccal occlusion (Fig. 8, Cases 1C and 1D).

Figure 8, Case 1, A and B top row, C and D bottom row.

CASE 2. An adolescent patient had congenitally missing upper lateral incisors (Fig. 9, Case 2A). After orthodontic treatment, the edentulous spaces were filled with pontics in an Essix™ bridge (Fig. 9, Case 2B).

Figure 9, Case 2A and B.

CASE 3. A preadolescent patient lost all her maxillary incisors when she bit into an electrical cord (Fig. 10, Case 3A). An Essix™ bridge incorporating both central and lateral incisor pontics was constructed (Fig. 10, Case 3B). Unlike most Essix™ bridges, this one was extended distal to the first molars for added stability and retention.

Figure 10, Case 3 A and B

CASE 4. An adult lost both maxillary central incisors in a car accident (Fig. 11, Case 4A). After orthodontic treatment, an Essix™ bridge was fabricated to replace the missing teeth. The patient wears a conventional Essix™ lower retainer.

Figure 11, Case 4 A and B.

CONCLUSION We have found the Essix™ temporary bridge to be superior in all respects to conventional devices. It is an inexpensive and aesthetic appliance that not only replaces missing anterior teeth, but also serves as an efficient retainer.

REFERENCES 1. Sheridan, J.J.; LeDoux, W.; and McMinn, R.; Essix™ retainer: Fabrication and supervision for permanent retention, J. Clin. Orthod. 27:37-45, 1993.

2. Sheridan, J.J.; Editor's Corner: The three keys of retention, J. Clin. Orthod. 25:717-718, 1991.