|Year : 2016 | Volume
| Issue : 2 | Page : 120-125
Indian Board of Orthodontics case report – Treatment of a severe Class II division 1 malocclusion with twin-block appliance and PEA
Professor and Head, Department of Orthodontics and Dentofacial Orthopaedics, K.L.E. Society's Institute of Dental Sciences, Bengaluru, Karnataka, India
|Date of Web Publication||8-Apr-2016|
Department of Orthodontics and Dentofacial Orthopaedics, K.L.E. Society's Institute of Dental Sciences, No 20, Yeshwanthpur Suburb, Bengaluru - 560 022, Karnataka
Source of Support: None, Conflict of Interest: None
This case was submitted to the board under category II for the Indian Board of Orthodontics examination, December 2008. The case summary, records, treatment progress, and critical appraisal are presented as submitted to the board. One-year posttreatment retention records were presented in the examination. The case report is updated with the long-term retention records of 7.5 years posttreatment to show excellent stability of the result.
Keywords: Class II division 1 malocclusion, Indian Board of Orthodontics case report, skeletal Class II malocclusion, twin-block appliance
|How to cite this article:|
Reddy S. Indian Board of Orthodontics case report – Treatment of a severe Class II division 1 malocclusion with twin-block appliance and PEA. J Indian Orthod Soc 2016;50:120-5
|How to cite this URL:|
Reddy S. Indian Board of Orthodontics case report – Treatment of a severe Class II division 1 malocclusion with twin-block appliance and PEA. J Indian Orthod Soc [serial online] 2016 [cited 2019 Feb 21];50:120-5. Available from: http://www.jios.in/text.asp?2016/50/2/120/179956
| Case Summary|| |
C.B.V, a 12-year-old female, presented with the chief complaint of forwardly placed upper front teeth. She had a Class II skeletal pattern with retrognathic mandible and Angle's Class II division 1 malocclusion with an overjet of 14 mm. A removable twin-block appliance with an expansion screw was used to reduce the amount of sagittal skeletal discrepancy. After the functional phase, nonextraction treatment was carried out with a preadjusted edgewise appliance – MBT prescription 0.022” slot. The duration of the treatment was 24 months. Maxillary circumferential retainer and mandibular bonded retainer from canine-to-canine were used for retention.
Section 1: Pretreatment assessment
Extraoral features: Profile – convex; clinical Frankfort mandibular angle – average; lip competence – incompetent; upper incisor exposure – 8 mm; nasolabial angle – obtuse; mentolabial sulcus – deep; size of nose and chin – normal [Figure 1][Figure 2].
Soft tissues: Frenal attachments – normal; oral hygiene: Fair
Erupted teeth present:
- General dental condition: Good
- Crowding/spacing – maxillary arch: Crowding of 3 mm; mandibular arch: Crowding of 7 mm.
General radiographic examination [Figure 3]
Pretreatment radiographs were taken using orthopantomogram (OPG) and lateral cephalogram.
- Teeth absent: None
- Teeth of poor prognosis: None.
Other relevant radiographic findings: Cervical vertebral maturation showed the deceleration phase of growth, CS4. Concavities in the bodies of CV 3, 4, and 5 were observed [Table 1].
Cephalometric interpretation – Rakosi Freiburg's analysis was also done.
Class II skeletal pattern with 7° ANB, Wits appraisal of 9 mm, and a unit length difference of 17 mm, orthognathic maxilla, retrognathic mandible, reduced mandibular corpus length, N-Se mandibular base – 20:18.5, maxillary base: Mandibular base – 2:2.8, normal lower facial height, average growth pattern, proclined maxillary incisors and mandibular incisors, protrusive lower lip, and an obtuse nasolabial angle were identified.
Skeletal Class II malocclusion with orthognathic maxilla, retrognathic mandible, a horizontal growth pattern, mesomorphic facial form, Angle's Class II division 1 malocclusion, narrow maxillary arch, crowding in both the arches, an increased overjet of 14 mm, and deep overbite of 6 mm were observed.
- Convex profile with retrognathic mandible
- Incompetent lips and lip trap
- Crowding in both the arches
- Class II molar and canine relationship
- Increased overjet
- Midline shifted to the left by 2 mm in the upper arch
- Midline shifted to the left by 4 mm in the lower arch
- Deep overbite.
Aims and objectives of treatment
- Reduction of sagittal skeletal discrepancy
- Achieving lip competency
- Expansion of the narrow maxillary arch
- Correction of crowding
- Correction of increased overjet
- Correction of Class II molar and canine relationship
- Correction of the shift in midlines
- Correction of deep overbite.
The treatment plan was growth modification therapy with a removable functional appliance, followed by nonextraction treatment with a fixed appliance.
- Removable twin-block appliance with an expansion screw and lower incisal capping [Figure 4]
- A preadjusted edgewise appliance – MBT prescription 0.022” slot.
Proposed retention strategy: Maxillary circumferential retainer and mandibular fixed retainer.
Additional notes on treatment plan
The prognosis for growth modification therapy was good in this case as the VTO (Visual Treatment Objective) was positive, the saddle angle was normal and mandibular retrognathism was due to the reduced corpus length. The patient had not attained menarche. The cervical vertebral maturation status showed the deceleration phase of growth CS4.
Randomized controlled trials have shown that favorable mandibular growth often occurs in adolescents and early treatment is not routinely superior in guiding growth. The best timing of treatment with twin-block appliance is at or slightly after the onset of peak in mandibular growth.
A systematic review, randomized, and prospective controlled trials have proved that the twin-block appliance is more efficient than the other removable functional appliances when used around the pubertal growth spurt.
A fixed appliance in conjunction with a fixed/removable functional appliance could have been used in this case. It is preferable to place a lower rigid wire with labial root torque in the anterior region to prevent incisor proclination while using functional appliances with a fixed appliance. Alignment and leveling in the lower arch would have delayed the placement of the functional appliance. Therefore, a removable twin-block appliance with an expansion screw and lower incisal capping was planned before the fixed appliance phase.
After the growth modification therapy, nonextraction treatment was planned with the preadjusted edgewise appliance, considering her increased nasolabial angle and the need for minimal retraction of the maxillary incisors.
Prognosis for stability: Good.
Section 2: Treatment
Postfunctional assessment [Table 2], [Figure 5] and [Figure 6]
- Maxillary arch spacing: 2.5 mm
- Mandibular arch crowding: 7 mm.
Postfunctional cephalometric interpretation [Figure 7]
- The sagittal skeletal discrepancy reduced. SNB angle increased by 2°; the Wit's value decreased by 4.5 mm
- The effective mandibular length increased by 9 mm
- The maxillary growth was not restricted
- The maxillary incisors retroclined by 4°
- The mandibular incisors proclined by 3°
- The mandibular and basal plane angles increased by 1° each
- The lower anterior facial height increased in relation to the upper face height
- The growth was expressed more horizontally as the Jarabak ratio increased by 1%.
Nonextraction treatment with MBT appliance was started. The sequence of wires used was 0.016” NiTi archwire, 0.018” AJW archwires, and 0.019”- 0.025” NiTi and stainless steel archwires. All these stages were documented with intraoral photographs [Figure 8].
Prefinishing photographs, study casts, and OPG and lateral cephalograms were taken and assessed with the prefinishing checklist for proper finishing of the occlusion.
Section 3: Posttreatment assessment
Posttreatment cephalometric interpretation [Figure 9]
- The sagittal skeletal discrepancy reduced as indicated by reduced ANB angle, Wits appraisal, and the increase in unit length difference
- The maxillary incisors were retracted by 9° in relation to SN plane
- The mandibular incisors proclined by 7° in relation to the mandibular plane
- Good vertical control was maintained during the treatment
- The nasolabial angle became more obtuse due to upward growth of the nose. The upper component of the nasolabial angle was 31° [Figure 10], [Figure 11], [Figure 12], [Figure 13], [Figure 14].
Section 4: Critical appraisal
The convexity of the profile and the interlabial gap at rest reduced. Lip trap was eliminated. The soft tissues adapted well to the changes in the hard tissues. Class I molar and canine relationship was achieved by a combination of skeletal and dentoalveolar changes. Although a slight relapse was observed after the functional phase, favorable intercuspation could be achieved at the end of treatment. Good cusp-fossa relationship could be observed from the lingual aspect of the posttreatment and retention study models.
|Figure 14: Comparison of pretreatment and long-term retention photographs|
Click here to view
Normal overjet and overbite were established. The midlines were coincident. The maxillary incisor inclination was almost ideal. The lower incisors proclined as expected. There was an increase in the incisor-mandibular plane angle from a pretreatment value of 99°–106° posttreatment. Considering the amount of sagittal skeletal discrepancy, increased nasolabial angle, and nonextraction treatment, moderately increased lower incisor inclination is acceptable. Appropriate root divergence was achieved for stability of the result in the lower anterior region.
Maxillary Hawley's retainer was given for 1 year. Bonded canine-to-canine retainer was used to prevent late mandibular incisor crowding.
The prognosis for stability was good. The result was stable 1-year posttreatment.
The photographs and study models made 7.5 years posttreatment showed excellent stability of the posttreatment occlusion.
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.
The author would like to express her gratitude to Dr. Arundhati P. Tandur for her valuable guidance to prepare for the IBO examination.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11], [Figure 12], [Figure 13], [Figure 14]
[Table 1], [Table 2]