A 7-year-old Iranian boy was attended to private orthodontic office with mild HM. In clinical examination, an asymmetric face and slight chin deviation to left detected in addition to strain on lip closure on chin soft tissue. The maximum mouth opening was at normal range and both condyles showed proper translatory movement; however, a deviation to left was present in opening. There was a maxillary cant of occlusion due to vertical deficiency of the mandible on the left side. There were no signs or symptoms of tempromandibular joint disease (TMD). The left ear was severely malformed and the left external auditory canal was absent. A reconstructive ear surgery was performed previously before beginning school at age of six years. The patient’s profile was convex and a mild chin deficiency was present (
Figure 1A - C).
Intra-oral examination revealed an increased overjet. The upper and lower incisors and first molars were completely erupted. The upper incisors were flared and spaced and a 2-mm midline deviation to right in comparison to facial midline was present in the upper arch. There was a 5.5 mm midline deviation between maxillary and mandibular midlines. In the upper and lower arches, the left first deciduous molars had a history of pulpotomy and large restorations accompanied with increased clinical mobility (
Figure 1D - H).
The space analysis using dental casts and radiographic tooth size prediction revealed a +2 mm tooth size-arch length discrepancy (TSALD) in the upper and +3 TSALD in the lower arch, respectively. The inter-arch molar relationship was CL II Angle on the right and CL III Angle on the left side, respectively.
Radiographic evaluation showed normal TMJ configuration including normal condyles on both sides. Cephalometric measurements revealed an asymmetric mandible with deficiency in sagittal plane. Both jaws showed a clockwise rotation and the gonial angle and sum of posterior angles were slightly increased, indicating a tendency toward vertical growth pattern (
Figure 1I and H).
Figure 1. Extraoral and Intraoral Pretreatment Photographs, Panoramic View and Lateral Cephalogram.
2.2. Treatment Alternatives
According to clinical and radiographic findings the treatment alternatives were:
1. An early surgical intervention for placing distractors and performing distraction osteogenesis (DO) for correcting vertical and sagittal mandibular deficiency on the left side, followed by comprehensive orthodontic treatment.
2. Two phase orthopedic/orthodontic treatment including growth modification and redirection by hybrid functional appliance and head gear (HG) followed by comprehensive fixed orthodontic treatment. Hybrid functional appliances constructed from acrylic and wire elements provide a proper environment for dentoalveolar and skeletal correction by forcing the mandible to be positioned correctly in the three dimensions of space. The resultant soft tissue stretch would help this phenomenon.
2.3. Treatment Plan
Considering the mild severity of the mandibular asymmetry and proper translatory movement of the both condyles in the glenoid foss, the DO approach discluded. Therefore, the second treatment alternative was selected for patient including growth modification followed by comprehensive fixed orthodontic treatment.
2.4. Treatment Progress
The right upper and lower first deciduous molars could not be restored, therefore extracted. Band and loop space maintainers were placed on the both right upper and lower second deciduous molars. Then an alginate impression was taken and wax construction bite was obtained to construct a hybrid functional appliance to advance mandible, bring the chin to the midline and correct vertical height deficiency in the left side. The hybrid functional appliance included a bite block on the right side and lingual and buccal shields on the left in addition to labial bows and retentive elements.
The functional treatment with hybrid appliance remained for 13 months with perfect compliance and nearly full-time wearing of the appliance. After this period, the mandibular deviation and vertical deficiency almost totally resolved and the treatment continued for another four months instructing the patient to wear appliance only at night during sleep (
Figure 2A - H).
Figure 2. Extraoral and Intraoral Photographs After Phase I of Treatment.
After this short maintenance period, the functional hybrid appliance discontinued; upper first molars were banded and a high pull HG was applied for vertical control. The patient continued wearing HG for about 14 months until establishment of a full permanent dentition. Then a full bonded orthodontic edgewise appliance was placed (Roth 22) and the second phase of treatment initiated reserving the high pull HG wearing. After initial leveling and alignment by 0.0175 stainless steel (SS) arch wire, the conventional sequence of wires placed up to 0.018 SS wire. CL II and CL III 3/16 medium elastics were applied on the left and right sides respectively for obtaining bilateral CL I dental relationship and preventing jaw deviation. 18.25 SS arch wires were used in finishing stage and final occlusion settling obtained on 16 SS arch wires using bilateral box elastics. Finally, occlusal adjustment was performed for achieving a proper functional and mutually protected occlusion. The second phase of treatment with fixed orthodontic appliance lasted for about 45 months.
Removable modified Hawley retainers with lingual shields for maintaining jaw relationship were used for retention. Patient was instructed to wear the retainers full-time, except at the meals and brushing for the first 12 months. Then the retainer wearing time reduced to nights only during sleeping.
2.5. Treatment Results
After completion of the first phase of treatment by means of hybrid functional appliance following high pull HG for vertical control, the facial asymmetry and mandibular deficiency were largely resolved. However, a fixed appliance treatment was necessary to obtain optimum esthetic, functional and stable results. At the end of fixed orthodontic treatment, bilateral CL I occlusal relationship and normal overjet and overbite were achieved (
Figure 3A - J). Total treatment time was about 72 months. The cephalometric tracing super impositions are presented in Figure 4 and before and after completed treatment measurements are presented in Table 1, respectively.
Figure 3. Extraoral and Intraoral Post-Treatment Photographs, Panoramic View and Lateral Cephalogram.
Figure 4. Pretreatment and Post-treatment Tracing Superimpositions
Table 1. Analytical Measurements Before and After Treatment
Angle Value Before Tx Value After Tx Norm SNA 77 73.2 82 SNB 69.5 67.3 80.9 ANB 7.5 5.8 1.6 U1-SN 103.9 97.3 103.1 IMPA 102.6 94 95 FMA (MP-FH) 36.2 34.6 22.9 Gonial 130.3 121.6 120.8
a Abbreviations: A, Point A; B, Point B; Gonial, angle between mandibular plane and ramus plane; L-1, long axis of decidous mandibular central incisor; L-1 to mandibular plane, angle between L-1 and mandibular plane; Mandibular plane, angle between mandibular plane and FH plane; N, nasion; S, sella turcica; SNA, angle between SN and NA; SNB, angle between SN and NB; U-1, long axis of deciduous maxillary central incisor; U-1 to FH plane, angle between U-1 and FH (Frankfort horizontal) plane.