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Clarification on Maxillary Expansion Objective and Appliances
by Lewis Klapper, D.M.D., MScD, DSc*

The purpose of this article is to summarize the problems addressed by maxillary expansion and to show how all treatment objectives can be met by an appropriately designed appliance. Biological issues and clinical management are addressed. Also discussed is the rationale for developing a new type of expander. The SUPERscrewTM, to improve the process for the patient and the doctor.

Orthopedic maxillary expansion has two basic goals. The first and most obvious is to correct the existing cross-bite and/or widen the maxilla and the maxillary dental arch. The second and less obvious goal is to improve the airway to allow nasal respiration.

The maxillary constricted patient is most commonly affected by allergies which create engorgement of nasal mucosa, enlargement of the adenoids and tonsils, depressed mandibular posture, forward resting tongue position, and mouth breathing. These patients have been shown to have less facial depth than average. The nasal respiratory obstruction and mouth breathing affect the musculature and produce a more vertical facial growth pattern and maxillary constriction. A high-vaulted palate is the result of the excess vertical maxillary growth at the aveolus and lack of lateral growth of the maxilla and aveolus due to the lack of lateral pressure from the tongue which is depressed and forward to facilitate oral breathing instead of resting against the maxilla (palate).

Therapy to correct the problems should be directed first at the most common causative factors. Adenoidal obstruction, when suspected, should be referred to an ENT for evaluation. Allergies should be diagnosed and managed by a Pediatrician or Allergist.

Orthopedic treatment should be directed at the maxilla with the goal of gaining as much airway expansion as possible to facilitate change from oral to nasal respiration. The nasal cavity expands less than half of the dental expansion achieved. It is desirable to over- correct the dental expansion during orthopedic treatment to gain as much expansion of the airway as possible even producing a buccal-cross-bite during expansion as recommended by Haas. It is also desirable, in an orthopedic appliance, to have as rigid an appliance as possible to allow more parallel translation of the maxillary halves, producing the most nasal enlargement.

Appliances currently on the market for expanding the maxillary dentition vary from simple tooth tipping devices to rigid orthopedic expanders. Among the tooth tipping devices are the removable Schwartz plate and "W" or spring types of stainless steel wire or nickel titanium. These are basically tooth tipping appliances due to their lack of rigidity either structurally or in their attachment to the teeth. They will not produce the desired airway expansion.

The orthopedic devices include various Hygienic, HAAS, and Bonded type appliances which have rigid screws attached to the maxillary teeth by bands or rigid acrylic (with or without acrylic against the palatal sides). These devices are designed to translate the maxillary halves outward. They enlarge the nasal airway space by translating the turbinates laterally with the maxillary halves, causing lowering of the vaulted palate and straightening of the nasal septum. This allows more airflow through the nasal cavity resulting in shrinkage of the mucosa and a decreasing nasal resistance. Air flow increases exponentially as the cross section is expanded. Conversion of oral to nasal respiration occurs if the resistance to airflow is adequately reduced. The resulting improvement in the direction of facial growth has be reported by Linder Aronson.

WHY WE SAW A NEED AND DEVELOPED A NEW TYPE
OF MAXILLARY EXPANDER!

Background of the Design Problem:

The orthodontic dilemma is that maxillas with the narrowest transverse dimension require the greatest expansion. This can require, at times, more than one expansion operation, i.e. two expansion appliances per patient. Even in the less constricted maxillas there is a problem fitting the expanders into the maxilla due to its narrow size. In addition to expanding the dentition, it is often necessary to over expand the maxilla widely to increase the dimension of the nasal cavity which improves the airway and nasal respiration as noted above. Failure to improve the airway impairment will compromise the long term success of the maxillary orthopedic expansion. In addition, over expansion is necessary because there is some relapse of expansion later on due to other biological factors.

Other Expander Solutions:

All other orthopedic expanders currently on the market are of the same basic design. They have a screw mechanism with a housing on each end attached to the teeth in some manner. Turning of the screw with a pin pushes the housings apart and expands the maxilla. When a greater expansion is required a longer screw is used. This is an inadequate solution as the longer screw is needed in the narrower cases where there is less room available to fit the expander.

Impact on Orthodontic Procedures:

Current practice of orthodontics frequently produces a compromised result. The orthodontist is forced to compromise the expansion in a significant number of cases because of the limited expansion that one can get with the expander that can fit in the narrow maxilla. This limits the over-expansion that can be achieved, compromises the airway improvement and creates a situation in which the orthodontist tries to correct the resulting problem with orthodontic wires. The alternative is to perform the expansion twice. This is disruptive to the orthodontic practice and the patient and requires multiple visits and complicated procedures. Usually the orthodontist will compromise the result and finish with one expander.

The SUPERscrewTM Solution:

The SUPERscrewTM is a nesting telescopic screw in which all the elements overlap. This provides the greatest possible expansion in the smallest space. Additionally, the transverse mounting of the attachment wires also reduces the amount of space needed to fit The SUPERscrewTM in the maxilla versus competing expanders.

Front Activation with a Hex Wrench:

This eliminates the conventional pin which is difficult for the parent to use and has been swallowed or inhaled by patients.

The use of the hex wrench eliminates this stress simplifying activation for the patient.

Greater Expansion:

The SUPERscrewTM expands a full 18 mm (12 mm for the new mixed dentition version). Most expanders currently come apart at 11 mm. These most often do not fit easily in the narrower maxillas because their wires are parallel to the screw.

Effective length of SUPERscrewTM
compared with traditional expander.

The Orthodontist being aware that it will come apart will stop short of their expansion capabilities and often achieve 8-9 mm. The SUPERscrewTM, either size, fits narrower cases. It offers maximum expansion and the orthodontist never worries about it coming apart or not having enough expansion.

Graduated Scale:

Current practice is to ask parents to keep track of the number of activations between office visits. Appliances are usually activated daily. This places the responsibility on the parent to remember both to perform the activation and to remember to record the activation. Any one with a household with a few children in today's busy schedule can appreciate that a few recordings or activations can be missed.

The parents have no visual way of knowing how much they have activated without this accurate record. As a result the orthodontists don't generally trust the parent's record and will see the patient frequently even worse the parents know they are inaccurate which causes anxiety over the expansion process. The orthodontist also can only guess as to expansion accomplished. Most often it is just a matter of "eye-balling" to decide the amount. The SUPERscrewTM has a graduated scale which shows the exact amount of expansion achieved at any time.

This reassures the parent that she/he is expanding appropriately. There is no recording necessary. The orthodontist also has control of the expansion outside of his office. This is very important, as most orthodontists have experienced expanders coming apart during treatment through over expansion by the parent who may have missed an appointment and continued activation. Consequently, most orthodontists with whom we speak try to see the patient frequently. They also limit their expansion to 8 mm or 9mm because of the uncertainty about the expansion achieved, distrusting the parent's record and their own measurement of expansion (most are not even sure which expander they are using as the outside lab or inside lab person does the ordering and tends to use the least expensive device). The graduated scale allows the parent to have confidence that expansion is on track and allows the orthodontist to expand maximally for the needs of the case. The scale forms the basis of this communication and can reduce patient visits because the orthodontist has better control over the expansion process. The parent's resulting confidence is an excellent practice image enhancer.

Friction Coating:

The SUPERscrewTM is friction coated to prevent back-turning during use. All other expanders will back-turn in a small but significant percentage. When an expander back- turns under tongue influence, the orthodontist has to remake the appliance from scratch an start over again. This is frustrating to the orthodontist and patient, and an added expense for the orthodontist. The SUPERscrewTM has a unique friction coating inside the hex sleeve. Thus prevention of back-turning can be guaranteed as the coating is in the hex sleeve portion which is an interchangeable part of any fabricated expander. It can be replaced if necessary with another one if it should fail to activate. The orthodontist can be assured that he will never have to remake an appliance due to back-turning.

Hygienic:

The SUPERscrewTM is the most hygienic expander on the market. Its rounded contours prevent the trapping of chunks of food between the palate and the expander. In addition the expander stays clean with tooth brushing. This feature is appreciated by the orthodontist and staff because hygiene is an important issue with braces.

Optional Locking Nut:

Orthodontists have traditionally been accustomed to fixating the appliance at the end of expansion to prevent back-turning. Fifty percent of the SUPERscrewTM users still prefer the locking feature even though the friction coating is present. No other expander offers this feature. To fixate other appliances the orthodontist must either place acrylic on the screw or tie a ligature wire through the holes in the screw.

Smallest Size for expansion amount:

The design of The SUPERscrewTM makes it effectively the smallest expander on the market for the greatest amount of expansion. The traverse wires enable the lab technician to fit The SUPERscrewTM either deeper in the palate or make it fit the narrowest of cases. The SUPERscrewTM, due to its telescoping design, gives the most expansion for its size. The 12 mm expands an additional 12 mm. The 16 mm expands and additional 18 mm. (Both expanders come apart 4 mm past their stated expansion.)

Major competitors cannot match smallness of size for expansion capability. Some examples are:

Hyrax/Palex 16 mm screw for 11 mm expansion
Leone 18 mm screw for 13 mm expansion
15 mm screw for 11 mm expansion
14 mm screw for 9 mm expansion
Forestadent 13 mm screw for 10 mm expansion
15 mm screw for 12 mm expansion
Lewa 22 mm screw for 10 mm expansion
15 mm screw for 8 mm expansion

Versatile:

There are several appliance techniques used today, Hygienic, HAAS type or bonded. The SUPERscrewTM can be fabricated in any of these techniques.

Materials used:

The best materials are used in the manufacture of The SUPERscrewTM; 316 stainless steel and special alloys along with laser welding techniques make The SUPERscrewTM a state of the art product and of the highest quality. Quality control is also of the highest level.

Pricing:

The SUPERscrewTM is competitively priced and price varies with quantity ordered. Priced from a low of $15.00 to $19.90 each. This includes the activating wrench. Pricing for competitive products vary from $10.50 to $18.90. But is there really any comparison?

Ordering Information:

*Technical information by: Dr. Lewis Klapper, D.M.D., MScD, DSc President, ORTHOdesign, Inc. Former Faculty and Chair, Orthodontics, Loyola School of Dentistry (Chicago 1978- 1993) Editor/Advisor to The Orthodontic CYBERjournal Private Practitioner

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