The Lip Bumper Alternative...
A Better Answer For Borderline Cases
by R. G. “Wick” Alexander, D.D.S., M.S.D.
In the years immediately following the birth of the Alexander Discipline in 1978, I was so pleased with treatment results that I anticipated only minor future refinements in appliance and technique. Similar to a modern language, however, the vitality of a growing orthodontic technique generates constant evolution through modifications brought about within the system and incorporation of elements of other techniques that enhance the discipline. Conversely, techniques in decline, like dead languages, stay the same. The Alexander Discipline has benefited from these growth dynamics while remaining true to its three goals: high quality result, ease and convenience for the patient, and minimized chair time.
With a Tweed background, I was taught and believed for many years that “expansion” was a bad word. My clinical experience and studies have taught me that, under proper conditions, many growing patients can accept an increase in the transverse dimension and remain stable. After having used lip bumpers in the past only to maintain molar anchorage, several years ago I took Dr. Norm Cetlin’s course. In studying his work, I realized that indeed there was another way to treat some patients with mandibular arch length discrepancies. Gaining space with lip bumpers in borderline cases can produce finished results with excellent non-extraction occlusion, nicely balanced profiles, and beautiful, broad smiles. Since then, with the benefit of years of clinical experience, I have developed my own criteria for determining appropriateness of lip bumper therapy as well as some ideas for lip bumper design improvement.
Based on my experiences, with the objective of maximizing appliance efficiency as well as patient comfort and acceptance, I designed a bumper with a modified plastic shield. I would like to describe the design advantages of the Alexander Lip Bumper, present an example of its effectiveness, discuss treatment considerations, and suggest how you can conveniently incorporate this technique into your practice.
I experimented initially with different designs, including those with plastic shrink tubing and those with plastic shields for the anterior section of the lip bumper. Included in my evaluation was participation in a study1 of lip bumper therapy response involving 40 patients. This study indicated a degree of clinical advantage with the plastic shields. There was no significant difference in the effect on incisor tipping no matter where the labial wire was positioned. Cases treated with plastic shield bumpers responded more favorable with distal movement of molar crowns and in gaining arch width in the molar and premolar areas.
Recognizing the advantages of shields, I designed one that would maximize efficiency while maintaining patient comfort and acceptance. The resulting Alexander Lip Bumper (Figure 1) has a hard plastic shield that provides the necessary surface area to transfer sufficient pressure from the lip to the molars while preventing the lips and the cheeks from applying pressure to the teeth. It is anatomically contoured to reduce anterior bulk, creating a comfortable as well as an efficient appliance. Three graduated sizes, built-in bayonet bends and an idealized arch form make fitting and adjustments quick and easy. A relatively flexible wire adds to comfort, and a gingival color for the plastic was selected to make the appliance less noticeable. Combined, the various small refinements of the Alexander Lip Bumper improve both clinical efficiency and patient acceptance of lip bumper therapy.
1Nevant, C.T., Buschang, P.H., Alexander, R.G., Steffen, J.M. Lip bumper therapy for gaining arch length. Am. J. Orthod. 1991; 100:330-336
Clinical Example :
Skeletal Class II Deep Bite, 12 year old female with End –on molar relationships, Overjet = 7 millimeters and Overbite 6 millimeters. (Figure 2 A-H Pre treatment Facial and Intraoral photos)
- Non extraction
- Rapid palatal expander
- Alexander Lip Bumper
- Cervical Face bow
Figure 3 is a pretreatment view of an illustrative case and reveals blocked out mandibular cuspids with a 6mm arch length discrepancy. In Figure 4 the discrepancy has been resolved by distal uprighting of the molars, slight advancement of the incisors, and only slight expansion of the intermolar width.
Lip bumper therapy was accomplished in 8 months; the second phase of full orthodontic treatment was then accomplished in 16 months for a total treatment time of 24 months. (Figure 5 A-H F Post treatment Facial and Intraoral photos.)
Another option for this case would have been extraction. It was felt, however, that the final occlusion, profile, and fullness of the smile would all be better with non-extraction treatment. Another alternative – interproximal stripping – is performed routinely in our office, but there was too great a discrepancy in this case.
Increase in the mandibular intermolar width should be attempted only after any needed maxillary intermolar expansion has been achieved (usually with an RPE).
Increasing the transverse dimension, along with the uprighting of molars and slight labial tipping of the incisors, can allow for a significant increase in mandibular arch length. After significant space has been gained using this “orthopedic” approach, the axial inclinations of the teeth are then efficiently positioned using the Alexander brackets and bands. This critical step, missing when using functional appliances, will provide improved artistic positioning of the teeth which will result not only in greater stability but also nicer esthetics.
Extraction vs. Nonextraction
In general, around 20% of our cases are definitely extraction cases and around 50% are definitely nonextraction. The remainder are what we call borderline cases, cases that we now treat using the transverse dimension to create space for the teeth and avoid extraction. Patients selected should have a normal or even concave profile, but not a bimaxillary protrustion which would probably call for extraction. We also have to be concerned about advancing incisors. Although the lip bumper will advance them approximately 3° in most of our cases, we are able to regain that and get the tooth upright by utilizing our archwire mechanics with the -5° mandibular incisor bracket torque.
Uprighting Mandibular 1st Molars
The lip bumper will upright the mandibular 1st molars, however, by placing a -6° angulation on the 1st molar bracket, this uprighting will improve the long term stability of the 1st molars.
Of the many advantages to this treatment technique, the biggest is the final occlusion obtained. The overall result is more beautiful, with a broad smile and, soft tissue wise, a pleasing profile that is not concave.
Acceptance is excellent. We are routinely using lip bumpers in early treatment (7, 8 and 9 year old patients). These patients are historically more cooperative anyway. The big motivator is that given a choice, most people prefer wearing a lip bumper to having teeth extracted. Patients realize that the lip bumper is only a six to twelve month requirement that makes the rest of the treatment go very easily. After adequate space has been gained with the lip bumper, a lingual arch is placed unless the arch is ready for complete bonding/banding.
Adjustments are made every four weeks in three dimensions: anterior-posteriorly, incisal-gingivally, and then buccal-lingually. The plastic shield should be 3-4mm away from the incisors and positioned right at the gingival line. It has been out experience that no matter where you position it, mandibular incisors will tip forward about 1.5° to 3°; this is confirmed in the previously mentioned study. If buccal-lingual expansion is wanted, the lip bumper is adjusted by expanding it approximately 5mm beyond the present intermolar width.
Cheek irritation is often the result of a patient’s sleeping position on the side of the face with a hand under the face. Once made aware of the problem, patients have little trouble changing their sleeping position and the problem usually disappears. When bad sores develop, patients are told to wear their lip bumpers only during the day until healing takes place. Loose bands can be a problem, so patients have to be cautioned against wiggling the lip bumper itself.
It is very easy to tell if lip bumpers are being worn. If the lip bumper has not moved at all from the previous month’s adjustment (when pulled out it still springs open and is still positioned 3-4mm in front of the mandibular incisors), it means that it has not moved, has not worked, and has not been worn. No debate.
Implementing Lip Bumper Treatment
A convenient way to begin this therapy is to start with a few lip bumpers and a small auxiliary kit of mandibular molar bands with prewelded lip bumper tubes must be used. With our technique, we order these tubes prewelded with a -6° tip.
The addition of lip bumper therapy to our practice has meant fewer extractions, better occlusion and more beautiful smiles. The advanced design of the Alexander Lip Bumper has brought additional efficiency and comfort to lip bumper mechanics. The lip bumper alternative has enabled us to achieve a better result in borderline cases in our practice.
Proper Timing with Class 2 Elastics
by R. G. “Wick” Alexander, D.D.S., M.S.D.
As in most things in life, “timing is everything.” Diagnostically, class II malocclusions can be classified as either skeletal or dental. In the Alexander Discipline, treatment of a skeletal class II case begins with headgear wear 8 – 10 hours each night. Almost every such case, however, class two elastics are worn toward the end of treatment to obtain final occlusion. If the case does not need orthopedic correction, this dental class II can be treated only with class two elastics.
Proper timing for elastic wear is critical during orthodontic treatment in the Alexander Discipline. It is very important that the final archwires in both arches, 17×25 stainless steel in an .018 slot, are fully engaged, tied back and have been in the mouth at least one month before class II elastics are initiated. At this point the minus 5 degree torque in the incisor brackets has been established. Also, the minus six degree tip in the lower first molars has uprighted these teeth allowing for additional anchorage. Therefore the posterior force of the class II elastics on the maxillary teeth and the anterior force on the mandibular teeth will not result in unwanted maxillary anterior retraction or mandibular anterior flaring.
It is also important to attach elastics to the appropriate teeth. Ideally, it is beneficial to maximize the horizontal component and minimize the vertical component while wearing these elastics. Most orthodontists attach class 2 elastics from the maxillary cuspids to the mandibular first molars. (Fig. 1) Consider the force vector. The vertical force component is significant. However in our approach, a more horizontal force component is used to achieve the sagital movement. This effect is obtained by attaching class 2 elastics to mandibular second molar brackets and to ball hooks attached to maxillary lateral incisor brackets. (Fig. 2) This more horizontal force vector reduces the bite opening tendencies of traditional Class II mechanics. If elastics attached in this manner are used for only a few months near the end of treatment, when heavier arch wires are in place and mandibular anchorage is preserved, little or no loss of torque or occlusal plane tipping will occur.
In the Alexander Discipline, class 2 elastics are not employed to open the bite. In a case with an extreme deep bite, the overbite will be corrected with reverse curve in the lower archwire and box elastics to the bicuspids. After the lower arch has leveled and the bite has opened, class 2 elastics will then be employed.
Occasionally, second molars are not fully erupted, yet elastics are required. In these instances, the elastics must be attached to the first molars. However, cases are not finished as a rule until the mandibular second molars have erupted and positioned properly.
In addition to skeletal class II correction, class 2 elastics are commonly used to correct the difference between centric occlusion (CO) and centric relation (CR). If early in treatment the patient has worn the extra oral appliance properly and has a good growth response, Class II elastics may not be required. Most often, however during the final stages of treatment, a slight CO/CR discrepancy remains.
There are a number of definitions of CO and CR. One version is as follows: Centric Occlusion- The occlusion of the mandibular and maxillary dentition when the patient bites down normally. Centric Relation- the occlusion created when the mandibular condyle is located in ideal position within the glenoid fossa.
Different clinicians may debate the location of this ideal position. In my thinking, the ideal position has the condyle being superiorly positioned while being centered within the fossa in the A-P dimension.
April 2013 Suggested Reading
Long-Term Stability in Orthodontics
With so many factors influencing long-term stability, such as the patient’s growth and habits, the treatment technique, the application of forces, and patient compliance, this book consolidates the 20 principles of the Alexander Discipline outlined in volume one into 6 guidelines for approaching long-term stability in orthodontics, focusing on the periodontium, torque control, skeletal and transverse control, occlusion, and the soft tissue profile.