The Multipurpose Use of Essix�? Thermoformed Appliances
June 2004
By Ana-Maria Morris, DDS and Francis Abadie, DDS
Oral Health Journal
ABSTRACT: Thermoformed Essix appliances have multiple uses in general dentistry and orthodontics, which greatly expand the many treatment options currently available. In office fabrication presents an additional asset, and because Essix appliances are clear plastic, the result is esthetically pleasing to the eye.
This article describes the most common and important applications, indications, fabrication techniques and the distinct advantages of using Essix thermoformed appliances.
Essix�? plastics have been accepted worldwide for their strength, clarity, size and cost. They are proven, consistent and guaranteed; providing absolute stability and esthetics which, make teeth appear brilliant. They are used for retainers, Minor Tooth Movement (MTM), temporary bridges, stabilization and protection of the osteointegrating implant, whitening trays, temporary bridges and mouthguards. All applications put the clinician in control, not outside labs.
Essix Retainers are versatile; their flexibility and positioning capabilities make them an alternative to spring retainers in correcting minor tooth movements.1 They do not interfere with hygiene care, as opposed to fixed retainers which can interfere with proper care.
Essix thermoformed appliances for Minor Tooth Movement can be easily activated with the Hilliard Thermopliers. With the pliers one can create space, increase retention, close diastemas and increase force adjustments. In addition, bodily movement, rotation, tipping and torquing are easily achieved. Bite planes can be fabricated with the Hilliard Thermopliers without bonding or otherwise adding to the appliance. Essix whitening trays adapt well and cling to tooth surfaces - superior to EVA material -- without distortion.
Because the whitening trays are plastic they are practically invisible. The Essix temporary bridge is superior in all respects when compared with other temporary devices. They are inexpensive and esthetic appliances that not only replace missing anterior teeth, but also serve as an efficient retainer. Essix mouthguards provide excellent protection against dental injuries, fractures and concussions during sports; particularly when bodily contact is involved.
The purpose of this article is to alert generalists and orthodontists to some of the multiple applications and techniques of the Essix appliances and the multiple benefits and uses of the Hilliard Thermopliers.
ESSIX RETAINERS
Orthodontists' concept of retention is moving toward the idea that teeth will move unless retained indefinitely.7,8 However, permanent retention implies permanent supervision, and that is where reality clashes with practicality. An orthodontic practice basically consists of the treatment of active cases, which consume the most time and generate the most income, and supervision of retention cases, which takes less time and produces minimal, if any, income. This balance has been workable because, in due course, retention patients are either dismissed with wishes of good luck or simply fade away. When permanent retention is emphasized, the equilibrium is upset.
As an example, if 200 patients per year are given permanent retainers and seen twice a year, after 10 years this will add up to 4,000 retention appointments per year. At 10 minutes per visit, that would take up about three months' worth of appointments.
The cornerstone of Essix permanent retention is the complete delegation of responsibility to the patient. Essix retainers have nothing to adjust; the only thing that could be done on a recall visit would be to check the patient's compliance and listen to any comments. Telephone supervision is a time-and-money-saving service to our patients and is sincerely appreciated.4,5
ADVANTAGES OF ESSIX RETAINERS
The advantages include: The ability to supervise without office visits, absolute stability of the anterior teeth, durability, ease of cleaning, low cost, ease of fabrication and the brilliant appearance of the teeth caused by light reflecting through the appliance.4 The retainers are worn only at night, changing the rules of permanent retention.
FABRICATION OF ESSIX RETAINERS
1. Because accuracy of the impression is paramount, it is recommended that a polyvinyl siloxane (PVS) system be used (Fig. 1). This is especially true for accurately recording cuspid to cuspid retaining points. Since full arches have many retaining points alginate (Cavex) may also be used.
2. Use Debubblizer in both the impression and stone mix (Fig. 2).
3. Use die stone (Essix stone) for dimensional accuracy.
4. By placing a "cola" can tab into the distal extent of the impression a neat stone model can be poured (Fig. 3).
5. The resulting cast should be trimmed so that its height is no more than 3/4" (2cm) which aids vacuum adaptation of the Essix plastic (Figs. 4 & 5).
WHICH PLASTIC TO USE?
Essentially there are two types of Essix plastic used to fabricate appliances. Essix A+�? is crystal clear and stiff. In use it lasts approximately six months. It is used for:
ǃ� Cuspid to cuspid retainers.
ǃ� Temporary bridges.
ǃ� Interim replacement over "fresh" implants.
ǃ� Wherever bonding is indicated.
ǃ� Secondary choice for use with Hilliard Thermopliers.
Essix C+�? has a slightly cloudy appearance but in place has contact clarity. It is the most widely used Essix plastic. Its life is about two years when in use. It is used for:
ǃ� Cuspid to cuspid and full arch retainers;
ǃ� Plastic of choice to use with all of the Hilliard Thermopliers (Essix C+ does not bond). Essix C+ is stabilized by spraying a coolant (Essix Freeze Spray) immediately upon thermoforming to achieve optimal retentive points and prevent "lift" of the plastic from the model (Fig. 6).
Essix appliances can be cut out and finalized with mayo scissors (Fig. 7).
The Essix Vacuum Machine compliments the use of Essix plastics when used with its Essix vacuum maximizers. The thermoforming machine renders ideal adaptation and accuracy (Fig. 8).
Note: Have the patient seat the appliance and bite down on articulating paper. Grind through any spots on the retainer in order that the complete occlusion occurs.
MINOR TOOTH MOVEMENT
Some prospective patients consider full orthodontia too costly or too lengthy (or both). Therefore, they simply decline the treatment.
Yet many, perhaps most of these patients could get the smile they want with only minor tooth movement of up to 3mm. This can be accomplished with relative ease and minimal expense with an Essix appliance modified with the Hilliard Thermopliers.
Smile enhancement techniques essentially require rotation, bodily movement, tipping, torquing, intrusion, extrusion, lateral movement, and/or opening a bite. All of these...any tooth movement... requires three things: space, force, and time.
SPACE -- There must be room in the arch for the tooth to move. For MTM, effective ways to create space include:
ǃ� Interproximal Reduction (IPR), reducing enamel with stainless steel strips in a movement not unlike flossing or stripping away enamel with slow-speed discs or burs.
ǃ� Air-Rotor Stripping (ARS); high-speed burs in the reduction of the proximal surface of a tooth.1
There must also be an opening within the thermoplastic appliance through which the target tooth can move. For without this opening, the tooth will not achieve any movement. The opening can be obtained three ways.
1. Cutting an opening into the thermoplastic appliance with the Essix Window Bur (Fig. 10).
2. Creating space, a bubble with Triad Gel or Blockout Compound, inside the appliance into which the targeted tooth can move (Fig. 11).
3. Creating a bubble inside the appliance into which the targeted tooth can move with the Hilliard Bubble-forming Thermopliers (Fig. 12). Heat the bubble tip of the Thermoplier and slowly squeeze the pliers on the targeted area of the appliance starting near the interproximal. Work the pliers around the area that the tooth will be moving into, bellying out the plastic as much as needed. It will be necessary to re-heat the pliers with the ATP Dental burner with each application, as it will cool (Fig. 13).
FORCE -- Pressure must be applied in the direction of desired movement.
Hilliard Thermopliers position each bump (divot) with complete precision. When plier tips are heated to correct temperature, the plastic retains its shape and the bump maintains its force. The same pliers can then increase the bump (force).
TIME -- Movement must be incremental over a number of weeks.
The Essix approach simply increases the force by increasing the bump as the tooth moves incrementally over time. Every few weeks, the patient returns and the bump is extended further, chairside and in a matter of seconds, again using Hilliard Thermopliers. When the appliance is worn full-time except while eating, a tooth can be moved approximately 1mm per month.
Chair time is reduced. Laboratory "back and forth" is totally eliminated all resulting in an increase in productivity, a reduction in overhead and improved patient satisfaction.2
ESSIX TEMPORARY ANTERIOR BRIDGES
The basic Essix appliance can be modified to serve as a temporary anterior bridge. The Essix technology provides a simpler, more efficient way to retain and replace missing anterior teeth. Exceptionally esthetic bridges can be fabricated quickly and inexpensive in the office. The appliances are made from .030" Essix A+.6
Technique
1. Fit a pontic of appropriate size and color into the edentulous area. Trim the base of the pontic to approximate the ridge (Fig. 14).
2. Cut a mesial-distal trench into the lingual surface of the pontic with the Essix trimming bur (Fig. 15).
3. Secure the pontic to the cast with Triad Gel (Fig. 16). Do not use wax, it will melt during thermoforming.4 Thermoform the Essix plastic over the cast.
5. The pontic will dislodge
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