Introduction
Class III malocclusions are one of the less common type of malocclusion, yet they are often more complicated to treat.1 It may occur as a result of skeletal and dental discrepancies leading to esthetic and facial impairment.2 Underlying cause for Class III malocclusion may be : 1) retrognathic and/or small maxilla; 2) prognathic and/or large mandible; 3) combination of both jaw discrepencies.3, 4 It has a multifactorial etiology involving genetic and environmental reasons.5 Prevalance of Class III malocclusion in Asian population ranges between 4% to 13%.6 In Indian population prevalence reported of Class III malocclusion is 3.4%.7 During the early phase of growth skeletal Class III patients with maxillary deficiency facemask or reverse pull headgear can contribute to the correction by application of orthopedic forces. So, early intervention is needed to obtain a more normal jaw relationship.8
Face mask consists of a metal framework which sits in front of the patients face with the support from the forehead and chin. Elastics are connected to the metal bar and the teeth - directly through intraoral appliances in the patient. The elastics apply forward and downward forces on the maxilla. Thus the force direction is the opposite from a standard headgear which is why this appliance is also known as a reverse-pull-headgear.9 The facemask appliance needs to worn by the patient for 12 to 14 hours daily.10 It is recommended that the age for effective treatment was ranges between 6 to 8 years (early mixed dentition) or 9 to 12 years (late mixed dentition).11 Facemask along with rapid maxillary expansion (RME) to protract the maxilla has become a treatment protocol in cases with maxillary deficiency.12 This article presents a case report of 12 years old boy having skeletal Class III malocclusion treated with facemask appliance followed by fixed appliance therapy.
Case Report
A 12-year-old male patient visited the Department of Orthodontics and Dentofacial Orthopedics with the chief complaint of forwardly placed lower front teeth.
No relevant medical or dental history was reported.
Clinical findings
Extraoral
The patient had mesoprosopic facial form, mesocephalic head shape with a concave facial profile, anterior divergence with deficiency in maxillary projection, decreased clinical FMA, acute nasolabial angle, average mentolabial sulcus and a protuded chin. No gross facial asymmetry was noticed. (Figure 1)
Intraoral
All teeth were present except 17,27. Patient had Angle's Class III molar and canine relation, anterior and posterior crossbite, negative overjet of -2 mm and overbite of 4mm. Ankyloglossia was seen.(Figure 2)
Cephalometric findings
Skeletal
Class III jaw base due to retrognathic maxilla and prognathic mandible, horizontal growth pattern.
Panoramic radiograph
Showed erupting second molars in upper quadrant and unerupted third molars in all quadrants except fourth quadrant and incomplete root formation of canines, premolars of all quadrant and second molars of lower quadrant. (Figure 3)
Treatment Objectives
To correct the skeletal discrepencies.
To achieve normal incisor axial inclination.
To achieve Class I molar, canine and incisor relation.
To achieve ideal alignment of upper and lower teeth.
To achieve ideal overjet and overbite.
To achieve an esthetic and pleasing facial profile.
Treatment plan
Based on the clinical examination and cephalometric evaluation showing skeletal Class III due to maxillary deficiency and the growth remaining it was decided to treat this case the by using orthopedic appliance. It was decided to use facemask to correct anteroposterior maxillary deficiency by protracting the maxilla and using expansion appliance as it disrupts the maxillary suture system and promotes maxillary protraction and to correct posterior crossbite simultaneously. After achievement of normal skeletal relationship followed by second phase of treatment with fixed orthodontic appliance for finishing and detailing
The treatment was carried out in two phases:
Phase I- Orthopedic correction with facemask and RME
Phase II - Dental correction and finishing and detailing with MBT prescription.
Treatment Progress
Phase I
The patient was given appliance which included protraction facemask and bonded maxillary splint (Haas type) with Hyrax screw (Leone, Italy). The expansion appliance was cemented and activation schedule of 1 turn in the morning was maintained for 3 weeks. In the expansion appliance hooks were incorporated on the buccal aspect near the permanent canines to engage the elastics for the facemask. After achieving the desired transverse dimension patient was asked to wear the facemask and the elastics. After a week facemask therapy was intiated with appliance worn for 12-14 hours a day. Initially force level was started at 200 g on each side which was later increased to 400 g after 2 weeks. The patient was asked to remove the appliance during eating and playing sports. The direction of the pull was downward and forward at an angle of around 30˚ to the maxillary occlusal plane. (Figure 4) The treatment duration of this phase was of 8 months. Appreciable clinical and radiographic changes were observed after phase I therapy. There was marked improvement in the profile of the patient (Figure 5, Figure 6) After the completion of active phase chin- cup was given for the retentive phase and subsequently during the fixed orthodontic treatment. (Figure 7)
Phase II
Post orthopedic traction fixed orthodontic treatment was started. Preadjusted edgewise appliances 0.022" slot MBT prescription was used (Figure 8). Initial levelling and aligning was done using niti wires 0.014, 0.016 x 0.022", 0.017x 0.025 followed by stainless steel wire 0.019 x 0.025. Finishing and detailing with 0.016 ss wire and light Class III elastics were given to maintain the overjet correction. Patient was asked to wear chin cup during the entire fixed orthodontic phase. Active treatment duration was about 1 year and 2 months. After debonding, lingual bonded retainer was given in lower arch and wrap-on retainer in the upper arch and the patient was asked to wear it for 1 year. (Figure 9).
Treatment Results
Post orthopedic and orthodontic treatment, improvement in facial profile was seen. Class I molar and canine relation was achieved with well aligned dental arches, normal overjet, overbite and matching midlines. Appreciable changes in the cephalometrics parameter of skeletal, dental and soft tissue was observed, evidenced by changes in ANB and Witts appraisal with increase in SNA angle. Improvement in the vertical skeletal measurements were also noted. (Figure 10). The comparision of pre-treatment, post-functional and post-treatment values are evident in Table 1, Table 2, Table 3. The cephalometric superimposition of the pre- and post-treatment radiographs were done which indicated favourable direction of patient growth towards class I skeletal and dental pattern. (Figure 11) After one year of follow-up the treatment changes and the profile of the patient was were found to be stable. (Figure 12).
Table 1
Comparison of skeletal changes in sagittal plane
|
Variable |
Pre-treatment |
Post-functional |
Post-treatment |
|
SNA |
83⁰ |
87⁰ |
87⁰ |
|
SNB |
92⁰ |
87⁰ |
88⁰ |
|
ANB |
-9⁰ |
0⁰ |
-1⁰ |
|
Wits |
-9mm |
-2⁰ |
-2⁰ |
|
Beta Angle |
39⁰ |
30⁰ |
31⁰ |
Table 2
Comparison of skeletal changes in Vertical Plane
|
Variable |
Pre-treatment |
Post-functional |
Post-treatment |
|
Go-Gn to SN |
26⁰ |
28⁰ |
28⁰ |
|
Y-Axis |
58° |
60⁰ |
60⁰ |
|
Basal plane angle |
26° |
27⁰ |
27⁰ |
|
Jaraback Ratio |
72.8% |
70% |
70% |
|
FMA |
24° |
25⁰ |
26⁰ |
Table 3
Comparison ofdento-alveolar and soft tissue changes
Discussion
While diagnosing the patient with skeletal imbalance age and growth stage is of utmost importance as the type and outcome of the treatment is dependent on it. When the patient is in the growth phase the intervention can be done using orthopedic or myofunctional appliances and desirable results can be seen. 12, 13 Various studies has been reported on Class III malocclusion treatment during early growing phase where facemask with RME therapy has been used to correct maxillary deficiency and redirect mandibular growth. 14 A long term study stated the effects of maxillary expansion during facemask therapy, concluded that average anterior movement of point A post treatment was 1.54 mm, and that of maxillary teeth were 2.73 mm. 15
In the present case, treatment was done in two phase therapy – in the first phase RME followed by facemask therapy to protract maxilla and later fixed orthodontic treatment for occlusal settling in the second phase. The skeletal growth pattern, age, appliance design and patient co-operation played a major role in correcting Class III malocclusion successfully.
Conclusion
Proper diagnosis and treatment mechanics is important to ensure better and long-term results in cases of skeletal discrepencies. If the predictable approach is done for a growing child, then effective skeletal dental and soft tissue outcome can be seen. Facemask with RME therapy given in cases of skeletal Class III patients during growth period modulates the active stages of craniofacial growth as well as dental development as shown in the case report.
Declaration of Patient Consent
The author certifies that he has obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that her name and initials will not be published, and due efforts will be made to conceal their identity.
