|Year : 2017 | Volume
| Issue : 4 | Page : 150-153
Phase I correction of skeletal Class III malocclusion with a modified tandem appliance
J Mohamed Iqbal, MD Sofitha
Department of Orthodontics, Tamil Nadu Government Dental College, Chennai, Tamil Nadu, India
|Date of Web Publication||11-Oct-2017|
J Mohamed Iqbal
Room No. 12, Department of Orthodontics, Tamil Nadu Government Dental College, Chennai, Tamil Nadu
Source of Support: None, Conflict of Interest: None
with this article
Skeletal Class III malocclusion is considered a syndrome with presentation differing in phenotype as well as genotype and inheritance. Class III malocclusion with retrognathic maxilla has a good prognosis for early treatment and face mask therapy is the traditional appliance of choice. However, patient compliance is a major deterrent. Modified tandem appliance is an effective alternative to face mask in bringing about the requisite changes along with excellent patient compliance, attributed to its minimalist design.
Keywords: Early treatment, modified tandem appliance, prognosis, skeletal Class III
|How to cite this article:|
Iqbal J M, Sofitha M D. Phase I correction of skeletal Class III malocclusion with a modified tandem appliance. Int J Orthod Rehabil 2017;8:150-3
| Introduction|| |
Class III skeletal malocclusion is a syndrome involving a retrognathic maxilla with normal mandible, normal maxilla with prognathic mandible or a combination of both. Correction of skeletal Class III malocclusion due to retrognathic maxilla in a growing patient using orthopedic modality has a good prognosis. Face mask therapy has been the appliance of choice for this treatment but the extraoral framework results in poor patient compliance and a deterrent to routine wear., Modified tandem appliance (MTA) is an intraoral two component appliance that can be an effective alternative to Facemask. It provides good patient compliance, comfort, and esthetics.
| Case Report|| |
A 6-year-old female patient reported with complaints of her upper front teeth seating behind the lower front teeth and a jutting lower jaw.
On extraoral examination, the patient was a mesocephalic, mesoprosopic individual with a concave profile, hypodivergent pattern of growth, and a decreased lower facial height [Figure 1]. Intraoral examination revealed a Class III molar relationship, a reverse over jet with a closed bite [Figure 2].
Cephalometric analysis was indicative of a retrognathic maxilla (SNA 78), mildly prognathic mandible (SNB 83) causing a Class III skeletal base (ANB 5) with a horizontal growth pattern [Table 1].
The treatment plan was to protract the maxilla and open the mandibular angle by clockwise rotation.
The MTA was used to bring about this orthopedic change. It is a two component appliance with a fixed maxillary unit incorporating a hyrax screw and hooks bilaterally in the deciduous canine-deciduous first molar region [Figure 3]. The mandibular unit is a cemented acrylic plate with a posterior bite plane incorporating tubes in the permanent molar region to receive a labial bow having soldered hooks in the anterior region [Figure 4] and [Figure 5]. The positioning of maxillary and mandibular hooks facilitates the application of elastic force to pass through the center of resistance of maxilla.
The appliance was fitted and expansion protocol of 1 turn per day for a week was followed. Subsequently, the parent was educated to apply heavy intermaxillary elastics generating 300-500 gms of force. The patient/parent was educated to wear the appliance for 12-14 hrs/day. The review was done every month. At the end of 6 months, sagittal correction was achieved with the forward movement of point A and backward movement of point B [Figure 6].
| Discussion|| |
The outcome of early treatment with orthopedic or functional modality is dependent on various factors, namely, the type of jaw discrepancy, the magnitude of discrepancy, and the time of intervention.
Correction of Class III skeletal malocclusion with orthopedic modality is approached with trepidation owing to unpredictable mandibular growth. However, a Class III skeletal malocclusion with retrusive maxilla has been shown to give good outcomes when protracted orthopedically.,
Mild skeletal disharmony, no familial prognathism, hypodivergent facial type, and good compliance are indicators of favorable prognosis in the correction of Class III skeletal malocclusion. Mandibular prognathism with normal maxilla contributing to the skeletal discrepancy is a deterrent to early treatment and should be delayed as late as postadolescence. A 4-year follow-up of face mask treatment in mixed dentition showed 67% of patients with good stability. The 33% with relapse had mandible outgrowing maxilla by four times compared to twice in the stable group.
Several methods have been proposed to predict mandibular growth as an indicator of prognosis to early treatment. Growth treatment response vector is an effective tool to make a decision about early treatment. Based on the horizontal growth of A point divided by the horizontal growth of B point, a ratio of 0.77 favors early intervention whereas a ratio of 0.60 or less points to surgical treatment.
The other contentious issue is with respect to timing of intervention in a Class III skeletal malocclusion with retrusive maxilla. Present best evidence indicates protraction with orthopedic force is effective in patients below 10 years of age and progressively becomes ineffective beyond that period.
| Conclusion|| |
A skeletal Class III malocclusion progressively worsens with time. The goals of early Class III treatment are:
- To prevent worsening of discrepancy
- To minimize dental compensations
- To eliminate centric relation/centric occlusion discrepancies and improve occlusal function
- To simplify phase II treatment.
Skeletal changes following orthopedic protraction are a result of forward movement of maxilla, clockwise rotation of mandible and decompensation of incisors. MTA effectively brings about these changes and negates the disadvantages of conventional face mask therapy, compliance and esthetics.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]