Download The Forsus™ Appliance: Characteristics and Clinical Case

The Forsus™ Appliance: Characteristics and Clinical Case
by Dr. Min-Ho Jung
Dr. Jung is a
clinical professor,
Department of
Orthodontics,
College of Dentistry,
Seoul National
University and Department of Orthodontics,
Samsung Medical Dental Center, and
is in private practice at SNU HONORS
Orthodontic Clinic, Seoul, South Korea. He
has published many articles in AJO/DO, JCO
and other journals. He is one of the directors
of the Korean Association of Orthodontists
and is also on the review board of the
Korean Journal of Orthodontics.
1.Is There an Evidence-Based Treatment Approach to
Treat Class II Malocclusions?
There are so many kinds of treatment options in treatment of Class II malocclusion.
When do you start to treat? Which appliance or mechanics do you prefer?
For children with a Class II malocclusion, the debate is not really whether or not it can
be corrected, because abundant evidence from clinical practice suggests it usually
can. The important questions are: (1) Does treatment started in mixed dentition, when
followed by a second phase during adolescence, provide superior results to singlephase treatment delayed until adolescence? (2) Is there enough additional gain for
patients, parents, and orthodontists to justify the greater burden of 2-stage treatment?
These questions can best be answered by following children with similar initial
malocclusions, who did or did not have early treatment, to late adolescence and
the completion of comprehensive treatment in the permanent dentition. For those
reasons, we should review randomized clinical trials (RCTs) to get answers about
these questions.
In 2007, the Cochrane Library released a systematic review of the efficiency of
2-phase treatment when initiated in patients between the ages of 7 and 9 years
to correct Class II.¹ The authors began their search of the literature by accessing
electronic databases available and then followed with a hand search of key
international orthodontic journals, with no restriction for language. To be included,
studies had to be randomized or controlled clinical trials.
The techniques used included various fixed or removable appliances or headgear, with
an untreated control group for comparison. The search strategy yielded 185 titles and
abstracts and from these, the authors obtained 105 reports for final investigation.
Significant differences were found in final overjet and ANB angle after phase I
treatment. But at the end of phase II, the authors found no significant differences in
overjet, final ANB, or peer assessment rating (PAR) scores between children who had
early treatment, with either headgear or functional appliances, and those who had
not received early treatment. Surprisingly, the authors also found that there was no
significant difference in the incidence of incisor trauma. According to Koroluk et al.,
orthodontic treatment should begin right after incisor eruption to reduce the possibility
of incisor trauma.²
The evidence suggests that early orthodontic treatment for children with Class II
malocclusion is no more effective than one course of treatment when the child is
in early adolescence. The only possible influence of early treatment would be the
temporary enhancement of self-esteem in early orthodontic treatment group.³
1A
compliance-free, fixed functional appliances have been
developed. Among those fixed functional appliances, I prefer to
use the Forsus™ Appliance in my office. It is compatible with
complete fixed orthodontic appliances and can be incorporated
into preexisting appliances. The Forsus appliance attaches at
the maxillary first molar and onto the mandibular archwire,
distal to either the canine or first premolar bracket. As the coil
is compressed, opposing forces are transmitted to the sites of
attachment.
1B
The action mechanism of Forsus appliance is shown in Figure
1A-C. Pushing force also causes an occlusal plane rotation
(Figure 1C) and the treatment result is very similar with Class II
elastics but the force could be given 24 hours per day, and the
treatment effect can be gained in relatively short time. Other
merits of Forsus appliances are as follows:
1C
•Forsus appliances did not show breakage in 5 million
compression cycle testing
Figure 1A-C: A. Action mechanism of Class II elastics. Upper and lower dentition
pulls each other so vertical vector may cause rotation of mandibular plane.
B. Action mechanism of fixed functional appliance. Pushing force would be helpful
to decrease the chances of clockwise rotation of the mandible. C. The Forsus™
Appliance’s action mechanism is similar with other fixed functional appliances.
Occlusal plane rotation might happen during Class II correction.
•Forsus showed consistent forces throughout 5 million
cycle testing
•It is very easy to use
•Fixed functional appliances show breakage problems during
treatment regardless of the appliance type.6,7,8 In case
of appliance breakage by biting or other reasons, Forsus
appliances can be easily repaired at chairside, which is an
advantage compared with other fixed functional appliances.
2.Characteristics of the Forsus™
Class II Appliance
If the best treatment timing for Class II patients is early
permanent dentition (or late mixed dentition if space is
required to solve some problems), it would be common to
use fixed appliances with or without other appliances such
as headgear, functional appliance or intermaxillary elastics to
correct Class II interarch relationship.
Today most adolescents, especially in Korea, are suffering
from extreme competition and a tight schedule of private
education. So it became more difficult to expect good
compliance to use headgear or Class II elastics. Poor
cooperation can lead to poor treatment results and increased
treatment time.4,5
For that reason, a compliance-free appliance is a good
treatment option for Class II treatment. A number of
2A-D
2G
Figure 2A-J: Pre-treatment.
2H
3. Clinical Case
History and Diagnosis
A 12-year-old female presented with the chief complaint of
an anterior crowding (Figure 2A-J). The length of her central
incisor root was little bit short. Her mother told me that she
frequently suffered from the common cold and inflammatory
tonsillar hypertrophy. She also showed a mild lip incompetency
and an open mouth posture while sleeping.
The diagnosis was Class II division 1 malocclusion with large
overbite and overjet (OB/OJ = 5.0/4.0 mm). She didn’t show
a noticeable facial asymmetry. Second molars were erupting.
Her profile was acceptable but showed a retrusive chin.
2E
2F
2I
2J
In model analysis, mild crowding (arch length discrepancy:
Mx 4.0 mm, Mn 2.5 mm) and Curve of Spee (2.5 mm) were
found. Bolton ratio was within normal range.
Because she did not want to use any additional appliance
that required cooperation, the Forsus™ Appliance was chosen
for her treatment.
3A
3B
Figure 3A-C: During leveling.
Treatment Progress
a. Leveling and alignment
•.022" × .028" Clarity™ Ceramic Brackets, MBT ™ System
prescription were bonded
3C
•.016" Ni-Ti wire
•.016", .018" Australian wire
•.019" × .025" Ni-Ti wire (Figure 3)
•.019" × .025" TMA wire with reverse Curve of Spee on
the lower arch
4A
•#17, 27 bracket bonding, #16, 26 band with tube
4B
Figure 4A-C: Using Forsus™
Appliances. Fractured spring can
be observed.
•Upper .018" × .025" Ni-Ti wire
•.019" × .025" stainless steel wire with soldered hook
b. The Forsus Appliance
•Use the Forsus appliance until achieving the proper
overbite and overjet (Figure 4A-C)
c. Finishing
•.019" × .025" stainless steel wire with steps
d. Retention
•Brackets were removed after bonding of fixed retainers
(Figure 5A-P)
Results Achieved
Her overbite, overjet and incisor irregularities were corrected.
In Figure 4A-C, you can see a fractured Forsus spring on the
left side and it was repaired easily.
During treatment, temporary acceleration of mandibular
growth and a small increase of nasal height made her profile
better. Because I wanted to minimize the distalization of the
upper arch, a full size rectangular stainless steel archwire
was engaged including upper second molar during Forsus
appliance treatment.
The Forsus appliance pushes the upper and lower dentition
reciprocally. But many reports show that in fixed functional
appliances, including Forsus appliances, the lower dentition
tends to move more than the upper dentition.9,10
4C
For those reasons, upper molars did not move distally as you
can see in superimposition tracing. Arch expansion and small
amount of stripping solved the upper arch crowding.
After debonding, an upper circumferential retainer and lower
Hawley retainer were used full time for 6 months. After 1 year
5 months, overbite, overjet and molar relationship were stable
(Figure 6A-I).
4.Conclusion
If you are not using the Forsus appliance in your practice, I
recommend you to try this easy and reliable appliance. The
Forsus appliance provides the compliance-free benefits to your
daily practice and its easily reparable feature minimizes clinical
problems during treatment.
Additional photos on next page
5A
5B
5C
5D
5I
5E-H
5J
5K
5M
5L
Figure 5A-P: Post-treatment.
5N
5O
5P
6A-D
6F
6E
6G
6H
6I
Figure 6A-K: 17 months after debonding.
6J
6K
References
1.Harrison JE, O’Brien KD, Worthington HV. Orthodontic treatment for prominent
upper front teeth in children. The Cochrane Library 2007, Issue 3. Art. No.:
CD003452. DOI: 10.1002/14651858. CD003452.pub2.
2.Koroluk LD, Tulloch JF, Phillips C. Incisor trauma and early treatment for Class II
division 1 malocclusion. Am J Orthod Dentofac Orthop 2003;123:117-26.
3.O’Brien K, Wright J, Conboy F, Chadwick S, Connolly I, Cook P, et al. Effectiveness
of early orthodontic treatment with the Twinblock appliance: a multicenter,
randomized, controlled trial. Part 2: Psychosocial effects. Am J Orthod Dentofac
Orthop. 2003;124:488-94.
4.Beckwith FR, Ackerman RJ Jr, Cobb CM, Tira DE. An evaluation of factors
affecting duration of orthodontic treatment. Am J Orthod Dentofacial Orthop.
1999;115:439-447.
5.Skidmore KJ, Brook KJ, Thomson WM, Harding WJ. Factors influencing
treatment time in orthodontic patients. Am J Orthod Dentofacial Orthop.
2006;129:230-238.
6.Schwindling FP. Jasper Jumper color atlas. Merzig:Schwindling;1997. p7-13.
7.Schiöth T, von Bremen J, Pancherz H, Ruf S. Complications during Herbst
appliance treatment with reduced mandibular cast splints: a prospective, clinical
multicenter study. J Orofac Orthop. 2007;68:321-7.
8.DeVincenzo JP. Treatment options for sagittal corrections in noncompliant
patients. In: Graber TM, Vanarsdall RLJr, Vig KWL editor. Orthodontics: Current
principles and techniques. St Louis: Elsevier Mosby; 2005. p. 888-96.
9.Jones G, Buschang PH, Kim KB, Ollver DR. Class II non-extraction patients
treated with the Forsus Fatigue Resistant Device versus intermaxillary elasitcs.
Angle Orthod 2008;78:332-8.
10.DeVincenzo J. The Eureka Spring: a new interarch force delivery system. J Clin
Orthod. 1997;31:454-67.
Photos provided by Dr. Min-Ho Jung. Permissions on file.
Reprinted from Orthodontic Perspectives Vol. XVI No. 1.
© 2009 3M. All rights reserved.