|
Simultaneous Dual Arch Development with Low Continuous Forces Utilizing Series 2000® Expansion Appliances: Treating to the Longterm Cosmetics of the Adult Face Michael
Owen Williams, DDS |
Introduction:
Understanding the past often helps us to see the future
more clearly, but in some instances, our past experiences can inhibit our
ability to discern the possibility for change. Transverse development of the
mandibular arch is considered an obstacle that limits success in some non-extraction
treatment protocols. (1) With previous techniques and materials
available, many clinicians have decided that these movements were either impossible
or undesirable. This has become a barrier to innovative treatment and, unfortunately,
a paradigm for the orthodontic profession. (2) With advances in
biomaterials, especially the introduction of “superelastic” arch wires, these
previously held beliefs are being challenged. Understanding the biology of
osteoblastic recruitment has also influenced our concepts of orthodontic movements
and dentofacial orthopedics. (3) Starting with the premises that
a “normal” anterior-posterior mandibular incisor position is inviolate and
stable, (4) and that transverse development of the maxillary arch
is known to have long-term stability. (5) A natural corollary would
suggest that transverse development of the mandibular arch should not be attempted
in isolation but should be closely linked to that of the maxilla and the new
operating environmental functional matrix dynamics created. Also that mandibular
arch development should not advance mandibular incisors excessively. These
concepts have led to the development of this family of orthodontic/orthopedic
appliance designs known as Series 2000®.
Appliance Description:
The MSX 2000® appliance (FIG.1)
is a combination of rods and tubes that are soldered to either bands or stainless
steel crowns and makes efficient use of the special properties of nickel titanium
coil springs. (6) At first glance it might appear that these appliances
were intended for lower molar distalization. However, the appliance has actually
been constructed to take advantage of transverse arch development in the mandibular
first bicuspid area. This is achieved in an active manner that is similar
to the passive manner advocated with Frankel’s Functional Regulator. (7,8)
Figure 1: MSX 2000® appliance for
The MSX 2000® is a fixed lower expander with
an unobtrusive low profile that facilitates hygiene maintenance and is easily
tolerated by patients of any age. In some respects this design can be described
as an adjustable lingual holding arch as prescribed by those advocates of
leeway space maintenance. (9,10) The rods and tubes allow the unloading of the
compressed nickel titanium springs to express a constant linear force and
promotes higher efficiency with a continuous light force system. This rod
and tube sliding design is well suited for the mandibular arch as any deformation
of the exposed rod elements will not affect the internal workings nor increase
friction of the sliding elements that are at work within the protected lumen.
These tubular components on the mandibular molars have two other advantages.
First they facilitate initial seating of the appliance and repositioning
of a loose segment without the removal of the entire appliance. A second advantage
is that the archial movement in the molar area allows the mandibular dentition
to respond to alterations of the maxillary dentition thus reducing the discomfort
often found when patients develop hyper-occlusion of individual teeth.
The Max 2000® (FIG.2) appliance
is a banded appliance designed with an acrylic and metal framework similar
to that of the Haas palatal expander (11) with one major difference.
A dual rod/tube spring mechanism has been substituted for the original expansion
screw. The dual rod/tube spring mechanism allows for a low continuous force
of 300 grams promoting efficient expansion.
The concept of dual arch development is often difficult
for clinicians to conceive. Arch length
discrepancies often are not recognized in the maxillary arch until the space
required for the maxillary canine eruption is deficient and many clinicians
still are reluctant to expand the maxillary arch in the absence of a buccal
cross bite. The Series 2000® system as presented is a matched and
mated system which allows for similar force systems to be applied across both
the mandibular and maxillary arches simultaneously. The advantages of these designs are in patient
comfort and treatment efficiency. They do not require patient activation and
answer requirements of a modern day practice with the present challenges placed
on the clinician by a non-compliant patient population. When there is a need
for both maxillary expansion and molar distalization then the DMAX 2000®
(Fig.3) should be substituted for the MAX 2000® design.
Figure 3: the DMAX 2000® for distalization and expansion
Case Report:
Each clinician has their preferences in the extraction
non-extraction debate. It has been
suggested that less than three millimeters of crowding is routinely considered
a non-extraction treatment decision, that 4-9 millimeters is debatable and
that ten millimeter or more of crowding is usually an extraction case. (12)
The case presented is one where a majority of clinicians would select an extraction
method of treatment. The patient is an Asian female of 13 years 4 months in
age with a Class I molar relationship and a Class II canine relationship.
She has an excessive overbite and over jet with severe mandibular crowding.
(Fig. 4) Lateral cephalometric
analysis indicates a mild maxillary retrusion and moderate mandibular retrusion
with a resulting Class II anterior-posterior skeletal tendency.
Transverse analysis also indicates a maxillary deficiency. (Fig.
5)
Figure 4: facial and intra-oral photographs indicative of a Class I crowded malocclusion
A non-extraction treatment plan was initiated with simultaneous
transverse development of both the mandible and maxilla utilizing a MSX 2000®
and MAX 2000® appliances. In conjunction a full bonded edgewise appliance
was placed. The “straight-wire” brackets consisted of a .018 slot with a Roth
prescription. The exception to this prescription was in the molar areas where
a Ricketts Bioprogressive philosophy with zero degree torque was employed.
Figure 5:
Lateral and PA cephalometric analysis illustrates AP and transverse maxillary
deficiency
Once the brackets and Series 2000® appliances are in
place the initial leveling process is the same as with any full bonded strap-up.
Each clinician has their own preferred method and sequence of leveling
depending on materials, slot size and experience. The one used in this case
consisted of a series of three arch wires, 16-nickel titanium followed by
a 16x22 nickel titanium and finished with a 16x25 stainless. (Fig. 6)
The selected arch wire sequence, size and material however are of little
value without a discussion of the arch perimeter or form desired. When the
initial clinical determination is made as to whether mandibular incisor crowding
can be alleviated by mandibular transverse development the transverse dimension
of the opposing arch is evaluated, in particular the distance from the cemento-enamel
junction of right to the left maxillary permanent first molars. (13)
Our arch form preference is related to having a finished treatment result
with increased bicuspid prominence and maxillary first molar width of a minimum
of thirty-six millimeters.
In evaluating the effect of the Series 2000® appliances,
it is important to note that the appliances are designed purposefully to have
the greatest vectors of force on the first bicuspid area. The mandibular canine
area is the least stable area for expansion and the first bicuspid area has
been determined to have a greater potential for successful transverse development
and stability. (14,15) This is the exact area that these appliances
have been designed to influence.
It is important to notice that the spacing is developing
in the bicuspid area distal to the canines. (Fig. 7) Paradoxically the first bicuspid extraction regimen
is the most common orthodontic treatment plan for facilitating correction
of a Class I crowded malocclusion. The decision to extract the first bicuspids
or even the deciduous first molars in an early serial extraction regimen can
stymie the possibilities of non-extraction mandibular arch development. (16)
Although non-extraction therapy in and of itself is not a goal of treatment,
it is significant to note that there are often overall facial proportional
improvements that occur with the development of the transverse dimension.
(Fig. 8)
Figure 8: Facial changes
possible with simultaneous transverse arch development.
It is this aspect of non-extraction treatment that is
facilitated with the proper use of the Series 2000® appliances. Clinicians
who are looking for this cosmetic result will notice the disappearance of “dark buccal corridors” and experience the pleasure
of a bicuspid prominence in their patient’s smile. Class I crowded malocclusions
can be successfully treated through several means, distalization of molars,
advancement of lower incisors or expansion distal to the canines. (17)
Distalization of first molars in all four quadrants is most feasible for those
who prefer second molar extraction to first bicuspid extraction. Simply bracketing
with “straight wire” appliances and leveling and alignment with continuous
arch wires will routinely advance the lower incisors to an unacceptable position.
One of the most promising attributes found when treating the permanent dentition
with a combination of the MSX 2000® expander and a full bonded
bracketed setup is that the cases are finishing without crowding and without
advancing the lower incisor as would happen normally with a straight wire
setup alone. (Fig. 9)
Figure 9: Initial and final dental superimpositions illustrate maintenance
of lower incisor position.
Discussion:
Diagnosis and treatment planning are the keys to success.
Each clinician defines the problem areas and then plans a treatment
that address for the most part each of the determined problems. Likewise,
in designing a new mandibular appliance past treatment philosophies or techniques
must be examined as well as the level of success that has been achieved through
these methods. When identifying mandibular arch crowding it is important to
determine where the crowding routinely exists.
It is noted that the mandibular first molar rarely erupts ectopically
and is guided by the position of the distal surface of the deciduous second
molar. Since the mesial-distal dimension of the mandibular second bicuspid
is significantly smaller than that of the deciduous second molar, this advantage
in arch length has led many to maintain that the mere preserving of this “
leeway space” can prevent the need for bicuspid extraction.
Due to a perceived inability to develop the mandibular arch and the
success in those cases where “leeway space” has been preserved, there are
many who have maintained that lower arch development is unnecessary.
(18) Early crowding of the mandibular dentition is not found in the
first molar area nor in the area of the deciduous second molar, it appears
that it is located between the mesial contacts of the deciduous second molars
until the permanent second molar erupts. Therefore the stable areas to choose
for transverse development are the first bicuspids. (19) By developing
more space for the natural eruption of the lower incisors adequate interproximal
alveolar bone is developed and normal periodontal ligament attachment patterns
are supported. Overlapping root proximity
due to anterior arch constriction in conjunction with abnormal periodontal
ligament attachment positions in them is adequate justification for early
treatment. Understanding where crowding truly exists in the mandibular arch
and where potential areas for mandibular arch development are have influenced
the mandibular expansion designs presented with the Series 2000®
family of appliances.
Figure 10: Facial and
dental proportions as our patient grows out of adolescents.
Conclusion:
Today’s
criterion for a well-treated orthodontic case requires far more than basic
tooth movement mechanics. It is critical
that the modern orthodontist understand the mechanisms of cranial-facial development,
facial growth and aging. (20) It is imperative for the clinician
to be able to build smiles that will be right for the adult face and that
they be able to individually growth forecast into late adulthood for results
that will last a lifetime. (Fig. 10) Orthodontists will no longer
be asked to create smiles that are satisfactory for the late adolescent face.
This need will best be served by visiting the often neglected third dimension
in orthodontics through developing transverse dimension on our young patients
so that they have smiles to grow into instead of building smiles that fit
the adolescent face but often become deficient as the patient enters adult
maturity and continues into the geriatric generation. (21) Series
2000® appliances were designed with this futuristic understanding
in mind. It is now possible to give
more than mere lip service to these new challenges.
*Series 2000® is a registered Trademark and
the appliance designs are protected by U. S. patent numbers: #5645422, #5769631,
#5919042, #6036488, #6241517,
#6402510, #6520722, and #6719557. All patent and Trademark rights are reserved
by Michael O, Williams, D.D.S.
For further information contact Dr Williams at:
REFERENCES: 1.
Little RM,
Riedel RA, Stein A. Mandibular arch length increase during the mixed dentition:
postretention evaluation of stability and relapse. Am J Orthod Dentofacial
Orthop. 1990 May;97(5);393-404. 2.
Dugoni
SA, Lee JS, Varela J, Dugoni AA. Early mixed dentition treatment: postretention
evaluation of stability and relapse. Angle Orthod. 1995;65(5):311-20. 3.
Miura F.
Reflections on my involvement in orthodontic research: New standard in biology
for clinical orthodontics, osteoclast recruitment. Am J Orthod Dentofacial Orthop. 1993 Dec;104(6);531-38. 4.
Schulhof
RJ, Allen RW, Walters RD, Dreskin M. The mandibular dental arch: Part I, lower incisor position. Angle Orthod. 1977 Oct;47(4):280-7. 5.
Spillane
LM, McNamara JA. Maxillary adaptation to expansion in the mixed dentition.
Semin Orthod. 1995 Sep;1(3):176-87. 6.
von Fraunhofe
JA. Bonds PW, Johnson BE. Force generation by orthodontic coil springs. Angle
Orthod. 1993 Summer;63(2):145-48. 7.
Frankel R, Frankel C. Clinical implication
of Roux’s concept in orofacial orthopedics. J. Orofac Prthop. 2001 Jan;62(1):1-21. 8.
Frankel
R. Possibilities of a late basal development of the mandible through the rearrangement
of the bite by means of a functional regulator. Dtsch Stomatol. 1971 Mar;21(3):198-202.
9.
Gianelly
AA. Leeway space and the resolution of crowding in the mixed dentition. Semin
Orthod. 1995 Sep;1(3):188-94. 10. Bishara SE. JCO Interviews. Samir E. Bishara on growth
and orthodontic treatment. J Clin Orthod. 1998 Jun;32(6):361-7. 11. Haas AJ. The treatment of maxillary deficiency by opening
the midpalatal suture. Angle Orthod. 1965 Jul;35:200-217. 12.
Proffit
WR. Contemporary Orthodontics, Mosby 3rd ed., 2000, p.224. 13.
McNamara
JA. Early intervention in the transverse dimension: Is it worth the effort.
Am J Orthod Dentofacial Orthop. 2002 Jun;121(6);572-4. 14. Lee RT. Arch width and form: A review. Am J Orthod Dentofacial Orthop. 1999 March;115(3);305-13. 15. Hime DL, Owen AH 3rd. The stability of the
arch-expansion effects of Frankel appliance therapy. Am J Orthod Dentofacial Orthop. 1990 Nov;98(5);437-45. 16.
17.
18.
Bishara
SE, Hoppens BJ, Jakobsen JR, Kohout FJ. Changes in the molar relationship
between the deciduous and permanent dentition:a
longitudinal study. Am J Orthod Dentofacial Orthop. 1988 Jan;93(1);19-28.
19. Weinber M, Sadowsky C. Resolution of mandibular arch
crowding in growing patients with Class I malocclusions treated nonextraction.
Am J Orthod Dentofacial Orthop. 1996 Oct;110(4);359-64. 20. Behrents RG. Looking at the adult face. Orthod Fr. 1997;68(1);35-40. 21. Moss JP. 2D or not 2D? That is the question. Am J Orthod
Dentofacial Orthop. 2000 May;117(5);580-1.