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Clinical Section |
The Royal London Hospital, London, UK
S. Ismail, Department of Orthodontics, Royal London Hospital, London E1 1BB, UK. E-mail: shamiqueismail{at}yahoo.com
The inaugural sitting of the Intercollegiate Membership in Orthodontics examination took place in the summer of 2000 in London. As a part of this new examination, the candidate with the highest overall mark in Part II of the examination is awarded the Intercollegiate MOrth medal.
This medal replaces the previous BSSO MOrth Medal, which was awarded by the Royal College of Surgeons of England, and is only awarded if the examiners feel the candidate’s performance is of a sufficiently high standard.
Part II of the examination includes a long clinical case, diagnostic tests, oral examinations, and the presentation of five personally treated clinical cases. The examiners choose two of these five cases to question the candidate as to their clinical ability and understanding of mechanics. Details of two of the treated cases are presented in this paper.
Case report 1
A 15-year 4-month-old Caucasian male was referred by his general dental practitioner complaining of the crooked appearance of his upper teeth. He presented with a Class II malocclusion on a mild skeletal III base with an increased Frankfort-mandibular planes angle and increased lower face height. His lips were competent at rest and his nasolabial angle was obtuse.
Intra-oral examination revealed the presence of all permanent teeth excluding the third molars. There was a hypoplastic pit on the upper right first molar, but otherwise the oral hygiene was good and the remainder of the dentition healthy. The lower arch had mild crowding anteriorly with retroclined lower incisors and a disto-angular lower right canine. The lower left canine was upright and was mesiolingually displaced. The upper labial segment was severely crowded with the upper left lateral incisor being palatally excluded. Both upper canines were distally angulated and there was a 1 mm midline diastema with no fraenal involvement. The buccal segments in both arches were well aligned.
In occlusion the incisor relationship was Class II division 2, with a 2 mm overjet, and an increased and complete overbite. The upper centre line was 1.5 mm displaced to the left side, whilst the lower was coincident with the midline of the face. The molar relationship was three-quarters of a unit Class II on the left side and half a unit Class II on the right side. The first molars on both sides and the left lateral incisors were in crossbite, with no associated displacement (Figure 1a–h
). The functional occlusion indicated non-working side contacts on the first molars bilaterally.
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shows the cephalometric values before and after treatment.
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The classification of treatment need for this malocclusion was 4d, the weighted PAR score prior to treatment was 32.
The aims of treatment were to:
The treatment plan is outlined below:
The lower second premolars were extracted to allow resolution of the crowding and allow a degree of arch contraction, thus helping with correction of the bilateral first molar crossbites. The upper arch extractions allowed relief of crowding and subsequent incorporation of the upper left lateral into the arch.
The total treatment time was 24 months. Treatment commenced with ‘pre-stage 1’ expansion of the upper arch using a quadhelix activated by half a molar width on each side. Once adequate expansion had been achieved the respective premolar teeth were extracted and stage 1 Tip-edge commenced. Conventional Tip-edge mechanics were not adopted in stage 1 due to the absence of a significant overjet and the potential worsening of the Frankfort-mandibular planes angle and lower face height, which may result from the use of inter-maxillary traction. Hence, all of the upper and lower teeth were bonded with 0.022 x 0.028-inch Tip-edge brackets, and flat 0.016-inch stainless steel (ss) archwires with circle loops mesial to both canines were inserted. Once a degree of levelling had been achieved, space was created for the upper left lateral incisor and the lower left canine by the use of open coil spring combined with E-links to aid retraction, on 0.020-inch ss archwires. Stage 2 involved the use of ‘E-links’ on 0.020-inch ss archwires to close the residual spacing. When this was complete, the quadhelix was removed and stage 3 Tip-edge was commenced using 0.0215 x 0.028-inch ss archwires and ‘sidewinder springs’. A lateral cephalogram was taken 4 months into stage 3, which confirmed the improvement in inter-incisal angle subsequent to the torquing effect of the ‘sidewinder springs’. Finishing required the use of a lower sectional braided 0.021 x 0.025-inch ss archwire and inter-maxillary seating elastics to allow closure of the mild lateral open bites. The patient was debonded after 24 months of treatment (Figure 2a–h). Upper and lower 0.0175-inch multi-strand stainless steel bonded retainers were placed in the upper and lower labial segments after debond; the lower one extending to the lower left first premolar due to the initial rotation of the lower left canine. Upper and lower Hawley retainers were also fitted to maintain the transverse correction and space closure.
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) indicated an almost vertical growth pattern; even without the use of inter-maxillary elastics. The incisor angulations improved due to the expression of palatal and lingual root torque on the respective incisors from the effect of the sidewinder springs on the archwires. This resulted in the inter-incisal angle decreasing by 17 to 143 degrees, and the edge-centroid relationship correcting such that the lower incisor tip was anterior to the root centroid of the upper incisor. The lower incisor angulation was still reasonably upright in the progress cephalogram. The lower inter-canine width has increased by 3 mm with treatment; this is likely to be stable in this case due to the initial lingual displacement of the lower left canine. The buccal root torque on the upper left lateral incisor could have been improved further; however, there is a definitive overbite associated with this tooth and so relapse of the crossbite is unlikely. At the end of treatment the patient exhibited bilateral group function for lateral excursion in dynamic occlusion; there were no non-working side interferences and anterior guidance with gentle posterior disclusion was evident on protrusion.
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Case report 2
A 10-year-old Caucasian female was referred by her general dental practitioner and was unhappy that her upper front teeth were sticking out. She presented with a Class II division 1 malocclusion on a moderate skeletal II pattern with a slightly reduced lower face height and a normal Frankfort-mandibular planes angle, but a retrusive facial profile. Her lower lip was ‘trapped’ behind her upper incisors at rest and she had an increased labiomental fold associated with an active mentalis muscle.
She presented in the mixed dentition, with all incisors and first molars present, as well as both lower canines partially erupted. Oral hygiene was poor at initial presentation but improved with instruction. The lower labial segment was moderately crowded and the lower left buccal segment was spaced due to early loss of the first deciduous molar. The upper labial segment was mildly spaced and proclined, and it was noted that the upper lateral incisors appeared disproportionately large. The upper buccal segments and the lower right buccal segment were well aligned.
In static occlusion the incisor classification was Class II division 1 and the molar relationship was a half unit post-normal bilaterally. The overjet was 12 mm to the left central incisor and 9 mm to the right incisor. The overbite was increased and complete to the palatal mucosa, with occasional trauma to the tissues, and both centre-lines were coincident with the midline of the face (Figure 4a–h). The lateral excursions were guided, on both sides, by the working side lower lateral incisors and the upper deciduous canines.
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.
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The aims of treatment were to:
A two-phase treatment plan was adopted in order to correct the patient’s malocclusion:
Phase 1
Phase 2
The first phase of treatment was commenced with a Type 2 Function Regulator (Figure 5). The vertical opening was approximately 5 mm and the mandible was postured forwards by the same amount. The patient initially wore the appliance in the evenings after school and during the day at weekends. The duration of wear was gradually increased to full time over the following month. Eight months into treatment the appliance was reactivated to bring the incisors to a Class I relationship. The appliance was worn full time for a further 8 months during which time the overjet reduced to 3 mm on the right side and 4 mm on the left. Although an over-correction was not achieved, it was decided to commence fixed appliance treatment. The buccal segments were in a Class I relationship and the residual overjet was accepted due to the tooth size discrepancy. The amount of crowding in the lower arch was 4mm, which combined with the 5 degrees proclination of the lower labial segment from the functional appliance phase of treatment indicated that extraction of lower second premolars was appropriate. This was matched with the extraction of the upper second premolars, and the use of a transpalatal arch to enhance anchorage. Subsequent to cementation of the transpalatal arch, upper and lower fixed appliances were placed using the Andrew’s prescription 0.022 x 0.028-inch slot size. Initial alignment was undertaken using nickel-titanium archwires, prior to consolidating the labial segments on 0.018-inch ss archwires. Space closure was commenced in 19/25-inch ss archwires, with the transpalatal arch in situ, which was removed after two visits of intra-arch traction. This helped to ensure that anchorage was conserved and eliminated any need for Class II inter-maxillary traction, which may have resulted in further proclination of the lower labial segment. Total treatment time was 34 months and following debond (Figure 6a–h), upper and lower Hawley-style retainers, with close fitting labial acrylic, were provided.
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The degree of skeletal improvement was moderate, despite the good compliance of the patient. This was due to growth changes occurring primarily in a vertical direction, as is indicated in the cephalometric superimposition (Figure 7).
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Acknowledgments
I would like to thank the staff at The Royal London Hospital and Essex County Hospital for their help during the period of my postgraduate training, in particular Mr R. T. Lee, Mrs M. Collins, and Mr R. A. Chate.
Received September 28, 2001; accepted October 18, 2001
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