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Class II malocclusion correction: An American Board of Orhodontics case
ABO CASE REPORT Class II malocclusion correction: An American Board of Orthodontics case Ronald J. Snyder, DDSa Apple Valley, Minn A Class II open bite malocclusion with a narrowed maxilla, an increased lower anterior facial height, and a tooth size discrepancy are presented. The malocclusion was treated nonextraction in 2 phases. The mixed dentition phase of treatment was maxillary molar uprighting followed by a bonded rapid palatal expander. The vertical dimension was managed with a vertical pull chincup. The full appliance phase included buildups of the maxillary lateral incisors and mechanics to control lower incisor position. (Am J Orthod Dentofacial Orthop 1999;116:424-9)
A
9-year 3-month old female presented with her parent’s complaint that “her teeth are not fitting together properly and she has poor eating habits.” She was a nocturnal bruxer as a toddler, and then a nocturnal thumb sucker until treatment began. A history of intermittent nasal obstruction and frequent tonsillitis was present throughout her development. Evaluations by an ear, nose, and throat specialist revealed an adequate nasopharyngeal airway with mild intermittent nasal obstruction as a result of allergies. The symptoms were mild enough that no medical treatment was recommended. DIAGNOSIS
The facial photographs (Fig 1) show a straight facial profile with a suggestion of an increased lower anterior facial height. The lips close without mentalis strain. On smiling, maxillary constriction is evident, as negative space is present in the buccal corridors. The dental casts (Fig 2) show Class II molar and canine relationships with an anterior openbite in the late mixed dentition. Wear facets are present on the primary canines and on the posterior primary and permanent teeth. Maxillary constriction is confirmed by the lack of buccal overjet and an end-to-end relationship between the maxillary primary canines and permanent mandibular canines. The transpalatal width (mesial gingival margins of the maxillary first molars) measured 30.5 mm, and the maxillary first molars were buccally inclined. The palatal vault was tall and tapering. The maxillary lateral incisors were small, creating a tooth aIn private practice. Reprint requests to: Ronald Snyder, DDS, 14065 Essex Ave, Apple Valley, MN 55124 Copyright © 1999 by the American Association of Orthodontists. 0889-5406/99/$8.00 + 0 8/4/93424
424
size discrepancy. Bolton’s tooth size analysis revealed a maxillary anterior deficiency of 2.7 mm. The panoramic radiograph (Fig 3) revealed a full complement of teeth with mesial eruption paths of the impacted maxillary canines. The canines partially overlapped the distally inclined maxillary lateral roots. The pretreatment cephalogram and its tracing (Fig 4) illustrate an increased mandibular plane angle of 37° and an increased lower anterior facial height percentage relative to the upper facial height. The SNA and SNB angles were both retrusive, and the ANB angle was within normal limits at 3°. Maxillary and mandibular incisors were felt to be well positioned over their respective bases with slight procumbency to the mandibular incisor. The nasiolabial angle was balanced. TREATMENT OBJECTIVES 1. Correct the Class II dental relationship and close the openbite. 2. Widen the maxillary base and increase the palatal volume; avoid excessive vertical descent of the maxillary dentition and of the maxilla during expansion. 3. Avoid excessive mandibular molar vertical eruption and avoid advancement of the mandibular incisor. 4. Control the lower anterior facial height and close the mandibular plane angle. 5. Balance the interarch tooth mass.
Attainment of these treatment objectives was dependent on controlling the vertical dimension during the expansion and during the full appliance stage of treatment. TREATMENT PLAN
To create fullness in the maxillary width and reduce the possibility of interrupting the balanced nasiolabial
Snyder 425
American Journal of Orthodontics and Dentofacial Orthopedics Volume 116, Number 4
Fig 1. Pretreatment facial photographs.
B
A
C Fig 2. Pretreatment dental casts.
angle, a nonextraction plan was chosen. Mechanics were designed to control mandibular incisor position. Build-up of the maxillary lateral incisors would balance dental relationships and aid malocclusion correction by balancing interarch tooth mass.
TREATMENT PROGRESS
In an effort to minimize dental side effects (vertical and transverse) of the rapid palatal expansion, the maxillary first molar buccal inclinations were first corrected. The molars were uprighted with a round,
426 Snyder
American Journal of Orthodontics and Dentofacial Orthopedics October 1999
Fig 3. Pretreatment panoramic radiograph. Fig 5. Progress mandibular cast.
constricted (0.032), transpalatal arch placed in precision lingual arch sheaths for 4 months. Once the molars were uprighted, rapid palatal expansion commenced with a bonded Hyrax appliance. The appliance was turned daily for 7 weeks and left in place for 8 weeks during the resting phase. A vertical pull chincup was worn throughout treatment, 10 to 12 hours per day. A palatal retainer and the vertical pull chincup held changes until the permanent dentition erupted and the family was ready to begin Phase II treatment (19 months). Edgewise treatment (0.022 × 0.028 preadjusted) involved a maxillary combi headgear and vertical pull chincup to a fully banded/bonded maxillary arch (with precision TPA) that supported a partially banded mandibular arch (laterals and second molars only) via Class III elastics to a 0.018 × 0.018 stopped and advanced mandibular arch wire (Fig 5). The elastics were only worn when the headgear was worn. The mandibular arch was aligned and level in 7 months (Class III elastics discontinued) when the remainder of the lower edgewise appliance was placed (including a precision lingual wire). Coil springs created space for 1.1 mm indirectly bonded buildups for each of the maxillary laterals (orthodontic bonding resin was used for the buildups). Finishing included 6 months of 5 oz Class II elastics and 4 months of headgear and chincup during retention (22 months, edgewise treatment). TREATMENT RESULTS
Fig 4. Pretreatment cephalogram (A) and tracing (B).
The facial photographs (Fig 6) show a marked improvement in the maxillary width as revealed by the full smile and the lack of negative space in the buccal corridors. Initiation of treatment in the mixed dentition interrupted the thumb habit and broadened the maxilla. The anterior open bite closed during the eruption of the
Snyder 427
American Journal of Orthodontics and Dentofacial Orthopedics Volume 116, Number 4
Fig 6. Posttreatment facial photographs.
B
A
Fig 7. Posttreatment dental casts.
permanent dentition. Increasing maxillary lateral tooth size helped the occlusal relationships and the esthetics (temporary buildups are present). The posttreatment dental casts (Fig 7) illustrate a
Class I occlusion with normal overjet and overbite. The buccal overjet has been improved. The mandibular canines, originally lingually inclined, were uprighted during treatment, resulting in 1.4 mm of expansion.
428 Snyder
American Journal of Orthodontics and Dentofacial Orthopedics October 1999
Fig 8. Posttreatment panoramic radiograph.
Fig 9. Posttreatment cephalogram (A) and tracing (B).
Fig 10. Pretreatment (solid lines) and posttreatment (dashed lines) superimpositions.
Snyder 429
American Journal of Orthodontics and Dentofacial Orthopedics Volume 116, Number 4
The panoramic radiograph (Fig 8) confirms that all roots are parallel and that minimal apical root loss occurred on the maxillary central incisors. The final cephalogram and its tracing (Fig 9) reveal that the mandibular plane angle closed 4°. The percentage of the lower anterior facial height to upper anterior facial height was reduced. The maxillary and mandibular molar vertical positions were controlled. Superimpositions (Fig 10) of the pretreatment and posttreatment cephalometric tracings show a vertical
pattern of facial growth with a significant increase in posterior lower facial height aiding the closure of the mandibular plane angle. The mandibular superimposition illustrates anchorage control of the mandibular dentition. This case report illustrates the esthetic benefits of maxillary expansion and maxillary lateral buildups. Further, it underscores the importance of controlling both the vertical dimension and mandibular anchorage to skeletally close an open bite while creating balanced dental relationships.
BOUND VOLUMES AVAILABLE TO SUBSCRIBERS Bound volumes of the American Journal of Orthodontics and Dentofacial Orthopedics are available to subscribers (only) for the 1998 issues from the Publisher, at a cost of $96.00 ($115.56 Canada and $108.00 international) for Vol. 113 (January-June) and Vol. 114 (JulyDecember). Shipping charges are included. Each bound volume contains a subject and author index and all advertising is removed. Copies are shipped within 60 days after publication of the last issue of the volume. The binding is durable buckram with the journal name, volume number, and year stamped in gold on the spine. Payment must accompany all orders. Contact Mosby, Inc, Subscription Services, 11830 Westline Industrial Drive, St Louis, MO 631463318, USA; telephone (314)453-4351 or (800)325-4177. Subscriptions must be in force to qualify. Bound volumes are not available in place of a regular Journal subscription.
A
9-year 3-month old female presented with her parent’s complaint that “her teeth are not fitting together properly and she has poor eating habits.” She was a nocturnal bruxer as a toddler, and then a nocturnal thumb sucker until treatment began. A history of intermittent nasal obstruction and frequent tonsillitis was present throughout her development. Evaluations by an ear, nose, and throat specialist revealed an adequate nasopharyngeal airway with mild intermittent nasal obstruction as a result of allergies. The symptoms were mild enough that no medical treatment was recommended. DIAGNOSIS
The facial photographs (Fig 1) show a straight facial profile with a suggestion of an increased lower anterior facial height. The lips close without mentalis strain. On smiling, maxillary constriction is evident, as negative space is present in the buccal corridors. The dental casts (Fig 2) show Class II molar and canine relationships with an anterior openbite in the late mixed dentition. Wear facets are present on the primary canines and on the posterior primary and permanent teeth. Maxillary constriction is confirmed by the lack of buccal overjet and an end-to-end relationship between the maxillary primary canines and permanent mandibular canines. The transpalatal width (mesial gingival margins of the maxillary first molars) measured 30.5 mm, and the maxillary first molars were buccally inclined. The palatal vault was tall and tapering. The maxillary lateral incisors were small, creating a tooth aIn private practice. Reprint requests to: Ronald Snyder, DDS, 14065 Essex Ave, Apple Valley, MN 55124 Copyright © 1999 by the American Association of Orthodontists. 0889-5406/99/$8.00 + 0 8/4/93424
424
size discrepancy. Bolton’s tooth size analysis revealed a maxillary anterior deficiency of 2.7 mm. The panoramic radiograph (Fig 3) revealed a full complement of teeth with mesial eruption paths of the impacted maxillary canines. The canines partially overlapped the distally inclined maxillary lateral roots. The pretreatment cephalogram and its tracing (Fig 4) illustrate an increased mandibular plane angle of 37° and an increased lower anterior facial height percentage relative to the upper facial height. The SNA and SNB angles were both retrusive, and the ANB angle was within normal limits at 3°. Maxillary and mandibular incisors were felt to be well positioned over their respective bases with slight procumbency to the mandibular incisor. The nasiolabial angle was balanced. TREATMENT OBJECTIVES 1. Correct the Class II dental relationship and close the openbite. 2. Widen the maxillary base and increase the palatal volume; avoid excessive vertical descent of the maxillary dentition and of the maxilla during expansion. 3. Avoid excessive mandibular molar vertical eruption and avoid advancement of the mandibular incisor. 4. Control the lower anterior facial height and close the mandibular plane angle. 5. Balance the interarch tooth mass.
Attainment of these treatment objectives was dependent on controlling the vertical dimension during the expansion and during the full appliance stage of treatment. TREATMENT PLAN
To create fullness in the maxillary width and reduce the possibility of interrupting the balanced nasiolabial
Snyder 425
American Journal of Orthodontics and Dentofacial Orthopedics Volume 116, Number 4
Fig 1. Pretreatment facial photographs.
B
A
C Fig 2. Pretreatment dental casts.
angle, a nonextraction plan was chosen. Mechanics were designed to control mandibular incisor position. Build-up of the maxillary lateral incisors would balance dental relationships and aid malocclusion correction by balancing interarch tooth mass.
TREATMENT PROGRESS
In an effort to minimize dental side effects (vertical and transverse) of the rapid palatal expansion, the maxillary first molar buccal inclinations were first corrected. The molars were uprighted with a round,
426 Snyder
American Journal of Orthodontics and Dentofacial Orthopedics October 1999
Fig 3. Pretreatment panoramic radiograph. Fig 5. Progress mandibular cast.
constricted (0.032), transpalatal arch placed in precision lingual arch sheaths for 4 months. Once the molars were uprighted, rapid palatal expansion commenced with a bonded Hyrax appliance. The appliance was turned daily for 7 weeks and left in place for 8 weeks during the resting phase. A vertical pull chincup was worn throughout treatment, 10 to 12 hours per day. A palatal retainer and the vertical pull chincup held changes until the permanent dentition erupted and the family was ready to begin Phase II treatment (19 months). Edgewise treatment (0.022 × 0.028 preadjusted) involved a maxillary combi headgear and vertical pull chincup to a fully banded/bonded maxillary arch (with precision TPA) that supported a partially banded mandibular arch (laterals and second molars only) via Class III elastics to a 0.018 × 0.018 stopped and advanced mandibular arch wire (Fig 5). The elastics were only worn when the headgear was worn. The mandibular arch was aligned and level in 7 months (Class III elastics discontinued) when the remainder of the lower edgewise appliance was placed (including a precision lingual wire). Coil springs created space for 1.1 mm indirectly bonded buildups for each of the maxillary laterals (orthodontic bonding resin was used for the buildups). Finishing included 6 months of 5 oz Class II elastics and 4 months of headgear and chincup during retention (22 months, edgewise treatment). TREATMENT RESULTS
Fig 4. Pretreatment cephalogram (A) and tracing (B).
The facial photographs (Fig 6) show a marked improvement in the maxillary width as revealed by the full smile and the lack of negative space in the buccal corridors. Initiation of treatment in the mixed dentition interrupted the thumb habit and broadened the maxilla. The anterior open bite closed during the eruption of the
Snyder 427
American Journal of Orthodontics and Dentofacial Orthopedics Volume 116, Number 4
Fig 6. Posttreatment facial photographs.
B
A
Fig 7. Posttreatment dental casts.
permanent dentition. Increasing maxillary lateral tooth size helped the occlusal relationships and the esthetics (temporary buildups are present). The posttreatment dental casts (Fig 7) illustrate a
Class I occlusion with normal overjet and overbite. The buccal overjet has been improved. The mandibular canines, originally lingually inclined, were uprighted during treatment, resulting in 1.4 mm of expansion.
428 Snyder
American Journal of Orthodontics and Dentofacial Orthopedics October 1999
Fig 8. Posttreatment panoramic radiograph.
Fig 9. Posttreatment cephalogram (A) and tracing (B).
Fig 10. Pretreatment (solid lines) and posttreatment (dashed lines) superimpositions.
Snyder 429
American Journal of Orthodontics and Dentofacial Orthopedics Volume 116, Number 4
The panoramic radiograph (Fig 8) confirms that all roots are parallel and that minimal apical root loss occurred on the maxillary central incisors. The final cephalogram and its tracing (Fig 9) reveal that the mandibular plane angle closed 4°. The percentage of the lower anterior facial height to upper anterior facial height was reduced. The maxillary and mandibular molar vertical positions were controlled. Superimpositions (Fig 10) of the pretreatment and posttreatment cephalometric tracings show a vertical
pattern of facial growth with a significant increase in posterior lower facial height aiding the closure of the mandibular plane angle. The mandibular superimposition illustrates anchorage control of the mandibular dentition. This case report illustrates the esthetic benefits of maxillary expansion and maxillary lateral buildups. Further, it underscores the importance of controlling both the vertical dimension and mandibular anchorage to skeletally close an open bite while creating balanced dental relationships.
BOUND VOLUMES AVAILABLE TO SUBSCRIBERS Bound volumes of the American Journal of Orthodontics and Dentofacial Orthopedics are available to subscribers (only) for the 1998 issues from the Publisher, at a cost of $96.00 ($115.56 Canada and $108.00 international) for Vol. 113 (January-June) and Vol. 114 (JulyDecember). Shipping charges are included. Each bound volume contains a subject and author index and all advertising is removed. Copies are shipped within 60 days after publication of the last issue of the volume. The binding is durable buckram with the journal name, volume number, and year stamped in gold on the spine. Payment must accompany all orders. Contact Mosby, Inc, Subscription Services, 11830 Westline Industrial Drive, St Louis, MO 631463318, USA; telephone (314)453-4351 or (800)325-4177. Subscriptions must be in force to qualify. Bound volumes are not available in place of a regular Journal subscription.