American Journal of ORTHODONTICS and DENTOFACIAL ORTHOPEDICS Founded in 1915
Volume 99 Number 3
March 1991
Copyright © 1991 by Mosby-Year Book, Inc.
CASE REPORT
An American Board of Orthodontics case report Correction of a Class 111 mandibular prognathism and asymmetry through orthodontics and orthognathic surgery Robert W. Baker, Jr., DMD, J. Daniel Subtelny, DDS, MS, and Bejan Iranpour, DDS Rochester, N.Y. The Class III malocclusion with mandibular prognathism can involve many factors, among which are excessive mandibular growth, underdevelopment of the maxilla, environmental factors, and trauma to the jaws. The correction of this malocclusion can involve an orthodontic or a combined orthodontic-orthognathic approach. Skeletal asymmetries can complicate this situation, making treatment either more difficult, more complicated, or both. This case presentation involves treatment with a combined orthodontic-orthognathic approach. [This case was presented to the American Board of Orthodontics in partial fulfillment of the requirements for the certification process conducted by the Board.] (AM J ORTHOD DENTOFACORTHOP 1991 ;99:191-201.)
CASE HISTORY The patient, a healthy girl of 15 years 2 months, came to the Eastman Dental Center, Department of Orthodontics, with the chief complaint of "my teeth and jaw relationship do not appear to be correct." Her past medical history included premature birth (about 2 months premature), moderate allergies and asthma, and repeated trauma to the infraorbital area apparently caused by several bicycle accidents that required medical attention.
CLINICAL EXAMINATION The patient had a prognathic profile, with a protrusive lower lip, and her lips were parted at rest (Fig. 1). She had a "short" upper lip, and the circumoral musculature appeared strained on lip closure. The lower facial height appeared excessive, with a small mentolabial sulcus and no nasolabial sulcus. The frontal view showed apparent mandibular and maxillary asymmetry, with the chin deviated to the patient's left.
Fromthe EastmanDentalCenter,Departmentof Orthodontics. 814121837
The left eye, left nares, and left commissure of the lip appeared more cranially positioned than comparable structures on the fight side. The posterior occlus~ll plane was sloped, with the left side positioned more cranially than the fight side. A bilateral posterior cross bite was evident (Fig. 2). Molar and canine relationships were Class Ill on both sides. The upper left first molar was missing. Intraarch anteroposterior asymmetry was noted, with the upper right canine and buccal segment positioned anteriorly to the upper left counterparts; the lower right canine and buccal segment were positioned posteriorly relative to the left .canine and buccal segment (Fig. 3). The patient's upper midface was coincident with the midpalatal suture, and the lower midline was 2 mm to the right. A mandibular right lateral shift of 0.5 mm was noted from initial dental contact to achievement of full dental closure. Arch length deficiencies of 1.0 mm in the mandible and 1.5 mm in the maxilla were noted.
CEPHALOMETRIC ANALYSIS Analyses of the cranial base measurements according to the Michigan cephalometrie standards revealed an obtuse "saddle angle" (N-S-BA), a short anterior cranial base (S-N), and a long posterior cranial base (S-BA). Upper anterior facial height (N-ANS) and upper posterior facial height (SE-PNS)
191
192
Am. J. Orthod. Dentofac. Orthop. March 1991
Baker, Subtelny, and Iranpour
Fig. 1. Age 15 yr. 2 too. Pretreatrnent facial photographs.
Fig. 2. Age 15 yr. 2 mo. Pretreatment intraoral photographs.
were within normal limits. Both lower anterior facial height (ANS-ME) and lower posterior facial height (Ar-Go) were excessive, with the lower anterior facial height being larger. Total facial height (N-Me) was excessive and the upper facial height/total facial height ratio was 44.6% compared with an average of 43.9% (Fig. 4).
Cephalometric evaluation of the maxilla revealed total maxillary length was short, and the maxilla and maxillary denture bases were retruded as the NA-FH and SNA angles were 86.5 ° and 77.0 °, respectively, with respective means of 89.8 ° and 84.8 °. A negative angle of convexity of - 14" and an A-B-to-facial plane measurement of + 6.0 indicated a con-
Volume 99 Number 3
Case report
"
193
i
i
Fi3. 3. Age 15 yr. 2 mo. Pretreatment model photographs.
cave skeletal profile with prognathic mandible. The upper left central incisor was slightly retroclined relative to the palatal plane and approximately 1.5 mm ahead of the A-P line. The facial plane angle and SNB angle revealed the mandible and mandibular denture base (93.0 ° and 82°) were ahead of the forehead or skeletally prognathic. The lower left central incisor was severely retroclined and approximately 3 mm ahead of the A-P line. Vertical relationships (Y axis and mandibular plane) revealed a vertical mandibular growth tendency with measurements of 60 ° and 30°, respectively.
The lateral headptate also revealed possible partial airway obstruction with probable inferior turbinate enlargement. Maxillary asymmetry was also present, with two levels of the hard palate plane and vertical discrepancies in J point and occlusal levels observable on the frontal radiograph. Mandibular measurements revealed an excessive body length (Go-Me) of 70 mm. Two lower borders of the mandible were noted, and the mandibular asymmetry was confirmed as the oblique radiographs revealed that effective length, ramal height, and body length were 1 mm to 4 mm greater on the right side than on the left side. Vertical eruptive differences
194
Am. J. Orthod. Dentofac. Orthop. March 1991
Baker, Subtelny, and Iranpour
15yr
FH-NPG 93 NA-FH 86.5 N - A - P G -14 M A N D P L 30 Y-AXIS 60 UFH/TFH 44.6 U I - P P L 113
2mo
......
I
; Fig. 4. A, Age 16 yr. 7 mo. Occlusal plane asymmetry. B, Age 15 yr. 2 mo. Pretreatment cephalometric tracing.
f3
\
,
Fig. 5. Age 18 yr. 7 too. Presurgical facial photographs. were noted as the upper left first molar was erupted 4 mm more than the upper right second molar (the right first molar was congenitally absent). The lower left first molar was erupted 2 mm more than the lower right first molar. The upper left central incisor was overerupted by 1 mm, and the lower left central incisor was undererupted by 2 mm according to the Michigan cephalometric standards. The skeletal growth
maturational indicator revealed that 89.5% of the maxillary growth and 84.0.% of the mandibular growth was complete.
DIAGNOSIS AND TREATMENT PLAN The objectives of the treatment plan were to correct or modify (1) maxillary deficiency (laterally and anteroposteri-
Volume 99 Nu~aber 3
Case report
195
Fig. 6. Age 18 yr. 7 mo. Presurgical intraoral photographs.
orly), (2) vertical maxillary asymmetry, (3) mandibular prognathism and the mandibular asymmetry, (4) posterior maxillary cross bite, (5) Class III malocclusion, (6) dental crowding, (7) short upper lip appearance, and (8) lateral mandibular shift. The decision was that the most favorable result could be achieved by a combined orthodontie-orthognathic surgical approach.
TREATMENT PROGRESS
A Haas-type palatal expander was placed to help achieve some maxillary lateral expansion. A lower lip bumper worn during the day and lower headgear worn at night were used to upright and distalize the lower molars in an effort to gain the necessary arch length. A lower first premolar-to-first premolar lingual G wire retainer was placed to hold the lower
Am. J. Orthod. Dentofac. Orthop. March 1991
196 Baker, Subtelny, and Iranpour
Fig. 7. Age 18 yr. 7 too. Presurgical model photographs.
anterior segment when crowding was relieved. Upper sectional wires were used incorporating rotation ties in conjunction with open coils to rotate the upper first and second molars. A high-pull headgear was used to tip the upper molars distally and to augment rotation. The palatal expander was discontinued after a 2-month period, and an upper continuous edgewise wire was then placed. A recurved Nance holding arch was cemented to augment rotation of the upper molars (left first molars and right second molars) and to minimize eruption of these teeth. The lower G wire retainer was moved, and straight sectional wires were used to consolidate the buecal segments. At this point the upper arch was fully bonded and
banded, and anterior labial root torque was achieved in the maxillary anterior segment incorporating labial root torque in the arch wire and tying it forward. Subsequent to full lower bonding, arch wire therapy was used to advance the lower incisors. Maxillary spaces were closed and the maxillary headgear was discontinued. The upper midline was moved to the left, and the lower arch was consolidated, with a bilateral continuous-closing loop arch wire. After this procedure, a mandibular right unilateral bite block was used to intrude the upper right second molar; concomitantly, the lower arch wire was constructed to intrude and to constrict the lower second molars. Buccal root torque and expansion were placed in the
99
Volume Number 3
Case report
18yr 7mo FH-NPG 95 NA-FH 89 N - A - P G -I0 M A N D PL 30 Y-AXIS 58.5 U F H / T F H 42.9 U I - P P L 108 LI-MPL -8
~~
_ ~
A --~
15~,~2vo
Fig. 8. A, Age 18 yr. 7 mo. Presurgical cepahlometric tracing. B, Superimposition of pretreatment and presurgical tracing.
18yr llmo FH-NPG 96 NA-FH 96 N-A-PG 0 M A N D PL 27 Y-AXIS 55 U F H / T F H 43. 0 U I - P P L iii LI-MPL -6
Fig. 9. Age 18 yr. 11 mo. Immediate postsurgical cephalometric tracing.
197'
198
Am. J. Orthod. Dentofac. Orthop. March 1991
Baker, Subtehly, and lranpour
Fig. 10. Age 21 yr. 6 mo. Occlusion photographs at time of retention. maxillary posterior segments through an arch wire adjustment (Figs. 5 and 6). The patient was then sent for a further surgical consultation, and a total maxillary osteotomy was recommended to achieve intrusion, rotation, and advancement, as well as a mandibular ramus osteotomy with rotation and set-back to compensate for the asymmetrical mandibular prognathism (Figs. 7 and 8). Surgical wires were then placed, and the
surgery was performed. The maxilla was rotated 2 mm to the right, intruded 2 mm on the left side and 5 mm on the right side, and advanced.approximately 3 mm. The mandible was set back approximately 5 mm and rotated 3 mm to the right. Intermaxillary fixation was placed after surgery. Postsurgical orthodontic treatment was reinitiated 2 months later (Fig. 9). This included expansion of the maxillary posterior segments through arch wire therapy and clo-
Volume 99 Number 3
Case report
199
Fig. 11. Age 21 yr. 6 mo. Maxillary labial retainer used in conjunction with maxillary lingual retainer.
21yr
6mo
FH-NPG 92 NA-FH 92.5 N-A-PG 2 M A N D P L 30 Y-AXIS 60 UFH/TFH 42 0 U I - P P L 108 LI-MPL -8
Fig. 12. Age 21 yr. 6 mo. Retention cephalometric tracing.
sure of spaces incident to the surgical procedure. Retention involved the use of a lower 7-~ G wire to minimize eruption of the lower molars and an upper 717 G wire to allow for the tongue to position itself as high as possible and to aid in keeping expansion (Fig. 10). A nighttime maxillary labial snap-on retainer was also provided to prevent any spaces from reopening (Fig. 1I).
RESULTS ACHIEVED The goals and objectives of treatment were satisfactorily met with combined orthodontic and surgical therapy (Fig. 12). The changes accomplished with orthodontic-surgical therapy (Fig. 13) included the reduction of upper anterior
facial height of approximately 5 mm and a reduction of posterior upper facial height of apprxoximately 2 mm. Total facial height was decreased by approximately 3 mm, while lower posterior facial height was decreased by almost 8 ram. Posttreatment upper facial-to-total facial height approximated 42%. The anteroposterior relationship of the maxilla to the forehead improved as the NA-to-FH angle increased by 6° and the SNA angle by 3.5 °. The angle of convexity also changed from - 1 3 ° to + 2 °, and the A-B to facial plane measurement changed from + 5 to - 6 °, showing a more favorable relationship of denture bases to each other and to the facial profile. After treatment, the upper incisor was bodily ahead of
200
Am. J. Orthod. Dentofac. Orthop. March 1 9 9 1
Baker, Subtelny, and lraIwour
__ l~ 18Y~7~o ..... ~ 2 1 ~ 6Me
/?¢
p\o.
o...
Fig. 13. Cephalometrie superimpositions of treatment progression.
kk
i ........................................................................................
Fig. 14. Age 21 yr. 6 too. Retention facial photographs.
the A-P line, which helped provide a more pleasing profile. The Ricketts E line measurements improved from - 12.5 mm (upper lip) to - 10 mm after treatment; the lower lip measurement was unchanged. The asymmetry in the maxillary jaw improved, as the frontal posttreatment radiograph revealed a more symmetrical vertical relationship than the pretreatment radiograph. In the mandibular region, changes re-
suiting in improvement in symmetry were noted as the rightside effective mandibular length, ramal height, and body length were reduced. In the anteroposterior relationships, the mandibular chin position was decreased by I mm, and the facial angle and SNB measurements were decreased by 1.5 ° and 4.5 °, respectively. Mandibular plane measurement did not change throughout treatment.
Volume 99 Number 3
Case report
201
Fig. 15, Age 21 yr. 6 mo. Retention model photographs.
SUMMARY After 3V2 years of posttreatment retention, the occlusion remained stable, and a very satisfactory result had been achieved. The facial skeletal and dental structures appeared to be in a more balanced relationship as the asymmetries described are much less pronounced than before treatment (Fig. 15). The patient is now being fitted with a maxillary lateral incisor-to-lateral
incisor lingual bonded retainer; mandibular retention will be removed within 3 months, at which time the patient will be recalled z/t 6-month intervals to check the stability of the result. Reprint requests to:
Dr. Robert W. Baker 412 N. Tioga St. Ithaca, NY 14850
Volume 99 Number 3
March 1991
Copyright © 1991 by Mosby-Year Book, Inc.
CASE REPORT
An American Board of Orthodontics case report Correction of a Class 111 mandibular prognathism and asymmetry through orthodontics and orthognathic surgery Robert W. Baker, Jr., DMD, J. Daniel Subtelny, DDS, MS, and Bejan Iranpour, DDS Rochester, N.Y. The Class III malocclusion with mandibular prognathism can involve many factors, among which are excessive mandibular growth, underdevelopment of the maxilla, environmental factors, and trauma to the jaws. The correction of this malocclusion can involve an orthodontic or a combined orthodontic-orthognathic approach. Skeletal asymmetries can complicate this situation, making treatment either more difficult, more complicated, or both. This case presentation involves treatment with a combined orthodontic-orthognathic approach. [This case was presented to the American Board of Orthodontics in partial fulfillment of the requirements for the certification process conducted by the Board.] (AM J ORTHOD DENTOFACORTHOP 1991 ;99:191-201.)
CASE HISTORY The patient, a healthy girl of 15 years 2 months, came to the Eastman Dental Center, Department of Orthodontics, with the chief complaint of "my teeth and jaw relationship do not appear to be correct." Her past medical history included premature birth (about 2 months premature), moderate allergies and asthma, and repeated trauma to the infraorbital area apparently caused by several bicycle accidents that required medical attention.
CLINICAL EXAMINATION The patient had a prognathic profile, with a protrusive lower lip, and her lips were parted at rest (Fig. 1). She had a "short" upper lip, and the circumoral musculature appeared strained on lip closure. The lower facial height appeared excessive, with a small mentolabial sulcus and no nasolabial sulcus. The frontal view showed apparent mandibular and maxillary asymmetry, with the chin deviated to the patient's left.
Fromthe EastmanDentalCenter,Departmentof Orthodontics. 814121837
The left eye, left nares, and left commissure of the lip appeared more cranially positioned than comparable structures on the fight side. The posterior occlus~ll plane was sloped, with the left side positioned more cranially than the fight side. A bilateral posterior cross bite was evident (Fig. 2). Molar and canine relationships were Class Ill on both sides. The upper left first molar was missing. Intraarch anteroposterior asymmetry was noted, with the upper right canine and buccal segment positioned anteriorly to the upper left counterparts; the lower right canine and buccal segment were positioned posteriorly relative to the left .canine and buccal segment (Fig. 3). The patient's upper midface was coincident with the midpalatal suture, and the lower midline was 2 mm to the right. A mandibular right lateral shift of 0.5 mm was noted from initial dental contact to achievement of full dental closure. Arch length deficiencies of 1.0 mm in the mandible and 1.5 mm in the maxilla were noted.
CEPHALOMETRIC ANALYSIS Analyses of the cranial base measurements according to the Michigan cephalometrie standards revealed an obtuse "saddle angle" (N-S-BA), a short anterior cranial base (S-N), and a long posterior cranial base (S-BA). Upper anterior facial height (N-ANS) and upper posterior facial height (SE-PNS)
191
192
Am. J. Orthod. Dentofac. Orthop. March 1991
Baker, Subtelny, and Iranpour
Fig. 1. Age 15 yr. 2 too. Pretreatrnent facial photographs.
Fig. 2. Age 15 yr. 2 mo. Pretreatment intraoral photographs.
were within normal limits. Both lower anterior facial height (ANS-ME) and lower posterior facial height (Ar-Go) were excessive, with the lower anterior facial height being larger. Total facial height (N-Me) was excessive and the upper facial height/total facial height ratio was 44.6% compared with an average of 43.9% (Fig. 4).
Cephalometric evaluation of the maxilla revealed total maxillary length was short, and the maxilla and maxillary denture bases were retruded as the NA-FH and SNA angles were 86.5 ° and 77.0 °, respectively, with respective means of 89.8 ° and 84.8 °. A negative angle of convexity of - 14" and an A-B-to-facial plane measurement of + 6.0 indicated a con-
Volume 99 Number 3
Case report
"
193
i
i
Fi3. 3. Age 15 yr. 2 mo. Pretreatment model photographs.
cave skeletal profile with prognathic mandible. The upper left central incisor was slightly retroclined relative to the palatal plane and approximately 1.5 mm ahead of the A-P line. The facial plane angle and SNB angle revealed the mandible and mandibular denture base (93.0 ° and 82°) were ahead of the forehead or skeletally prognathic. The lower left central incisor was severely retroclined and approximately 3 mm ahead of the A-P line. Vertical relationships (Y axis and mandibular plane) revealed a vertical mandibular growth tendency with measurements of 60 ° and 30°, respectively.
The lateral headptate also revealed possible partial airway obstruction with probable inferior turbinate enlargement. Maxillary asymmetry was also present, with two levels of the hard palate plane and vertical discrepancies in J point and occlusal levels observable on the frontal radiograph. Mandibular measurements revealed an excessive body length (Go-Me) of 70 mm. Two lower borders of the mandible were noted, and the mandibular asymmetry was confirmed as the oblique radiographs revealed that effective length, ramal height, and body length were 1 mm to 4 mm greater on the right side than on the left side. Vertical eruptive differences
194
Am. J. Orthod. Dentofac. Orthop. March 1991
Baker, Subtelny, and Iranpour
15yr
FH-NPG 93 NA-FH 86.5 N - A - P G -14 M A N D P L 30 Y-AXIS 60 UFH/TFH 44.6 U I - P P L 113
2mo
......
I
; Fig. 4. A, Age 16 yr. 7 mo. Occlusal plane asymmetry. B, Age 15 yr. 2 mo. Pretreatment cephalometric tracing.
f3
\
,
Fig. 5. Age 18 yr. 7 too. Presurgical facial photographs. were noted as the upper left first molar was erupted 4 mm more than the upper right second molar (the right first molar was congenitally absent). The lower left first molar was erupted 2 mm more than the lower right first molar. The upper left central incisor was overerupted by 1 mm, and the lower left central incisor was undererupted by 2 mm according to the Michigan cephalometric standards. The skeletal growth
maturational indicator revealed that 89.5% of the maxillary growth and 84.0.% of the mandibular growth was complete.
DIAGNOSIS AND TREATMENT PLAN The objectives of the treatment plan were to correct or modify (1) maxillary deficiency (laterally and anteroposteri-
Volume 99 Nu~aber 3
Case report
195
Fig. 6. Age 18 yr. 7 mo. Presurgical intraoral photographs.
orly), (2) vertical maxillary asymmetry, (3) mandibular prognathism and the mandibular asymmetry, (4) posterior maxillary cross bite, (5) Class III malocclusion, (6) dental crowding, (7) short upper lip appearance, and (8) lateral mandibular shift. The decision was that the most favorable result could be achieved by a combined orthodontie-orthognathic surgical approach.
TREATMENT PROGRESS
A Haas-type palatal expander was placed to help achieve some maxillary lateral expansion. A lower lip bumper worn during the day and lower headgear worn at night were used to upright and distalize the lower molars in an effort to gain the necessary arch length. A lower first premolar-to-first premolar lingual G wire retainer was placed to hold the lower
Am. J. Orthod. Dentofac. Orthop. March 1991
196 Baker, Subtelny, and Iranpour
Fig. 7. Age 18 yr. 7 too. Presurgical model photographs.
anterior segment when crowding was relieved. Upper sectional wires were used incorporating rotation ties in conjunction with open coils to rotate the upper first and second molars. A high-pull headgear was used to tip the upper molars distally and to augment rotation. The palatal expander was discontinued after a 2-month period, and an upper continuous edgewise wire was then placed. A recurved Nance holding arch was cemented to augment rotation of the upper molars (left first molars and right second molars) and to minimize eruption of these teeth. The lower G wire retainer was moved, and straight sectional wires were used to consolidate the buecal segments. At this point the upper arch was fully bonded and
banded, and anterior labial root torque was achieved in the maxillary anterior segment incorporating labial root torque in the arch wire and tying it forward. Subsequent to full lower bonding, arch wire therapy was used to advance the lower incisors. Maxillary spaces were closed and the maxillary headgear was discontinued. The upper midline was moved to the left, and the lower arch was consolidated, with a bilateral continuous-closing loop arch wire. After this procedure, a mandibular right unilateral bite block was used to intrude the upper right second molar; concomitantly, the lower arch wire was constructed to intrude and to constrict the lower second molars. Buccal root torque and expansion were placed in the
99
Volume Number 3
Case report
18yr 7mo FH-NPG 95 NA-FH 89 N - A - P G -I0 M A N D PL 30 Y-AXIS 58.5 U F H / T F H 42.9 U I - P P L 108 LI-MPL -8
~~
_ ~
A --~
15~,~2vo
Fig. 8. A, Age 18 yr. 7 mo. Presurgical cepahlometric tracing. B, Superimposition of pretreatment and presurgical tracing.
18yr llmo FH-NPG 96 NA-FH 96 N-A-PG 0 M A N D PL 27 Y-AXIS 55 U F H / T F H 43. 0 U I - P P L iii LI-MPL -6
Fig. 9. Age 18 yr. 11 mo. Immediate postsurgical cephalometric tracing.
197'
198
Am. J. Orthod. Dentofac. Orthop. March 1991
Baker, Subtehly, and lranpour
Fig. 10. Age 21 yr. 6 mo. Occlusion photographs at time of retention. maxillary posterior segments through an arch wire adjustment (Figs. 5 and 6). The patient was then sent for a further surgical consultation, and a total maxillary osteotomy was recommended to achieve intrusion, rotation, and advancement, as well as a mandibular ramus osteotomy with rotation and set-back to compensate for the asymmetrical mandibular prognathism (Figs. 7 and 8). Surgical wires were then placed, and the
surgery was performed. The maxilla was rotated 2 mm to the right, intruded 2 mm on the left side and 5 mm on the right side, and advanced.approximately 3 mm. The mandible was set back approximately 5 mm and rotated 3 mm to the right. Intermaxillary fixation was placed after surgery. Postsurgical orthodontic treatment was reinitiated 2 months later (Fig. 9). This included expansion of the maxillary posterior segments through arch wire therapy and clo-
Volume 99 Number 3
Case report
199
Fig. 11. Age 21 yr. 6 mo. Maxillary labial retainer used in conjunction with maxillary lingual retainer.
21yr
6mo
FH-NPG 92 NA-FH 92.5 N-A-PG 2 M A N D P L 30 Y-AXIS 60 UFH/TFH 42 0 U I - P P L 108 LI-MPL -8
Fig. 12. Age 21 yr. 6 mo. Retention cephalometric tracing.
sure of spaces incident to the surgical procedure. Retention involved the use of a lower 7-~ G wire to minimize eruption of the lower molars and an upper 717 G wire to allow for the tongue to position itself as high as possible and to aid in keeping expansion (Fig. 10). A nighttime maxillary labial snap-on retainer was also provided to prevent any spaces from reopening (Fig. 1I).
RESULTS ACHIEVED The goals and objectives of treatment were satisfactorily met with combined orthodontic and surgical therapy (Fig. 12). The changes accomplished with orthodontic-surgical therapy (Fig. 13) included the reduction of upper anterior
facial height of approximately 5 mm and a reduction of posterior upper facial height of apprxoximately 2 mm. Total facial height was decreased by approximately 3 mm, while lower posterior facial height was decreased by almost 8 ram. Posttreatment upper facial-to-total facial height approximated 42%. The anteroposterior relationship of the maxilla to the forehead improved as the NA-to-FH angle increased by 6° and the SNA angle by 3.5 °. The angle of convexity also changed from - 1 3 ° to + 2 °, and the A-B to facial plane measurement changed from + 5 to - 6 °, showing a more favorable relationship of denture bases to each other and to the facial profile. After treatment, the upper incisor was bodily ahead of
200
Am. J. Orthod. Dentofac. Orthop. March 1 9 9 1
Baker, Subtelny, and lraIwour
__ l~ 18Y~7~o ..... ~ 2 1 ~ 6Me
/?¢
p\o.
o...
Fig. 13. Cephalometrie superimpositions of treatment progression.
kk
i ........................................................................................
Fig. 14. Age 21 yr. 6 too. Retention facial photographs.
the A-P line, which helped provide a more pleasing profile. The Ricketts E line measurements improved from - 12.5 mm (upper lip) to - 10 mm after treatment; the lower lip measurement was unchanged. The asymmetry in the maxillary jaw improved, as the frontal posttreatment radiograph revealed a more symmetrical vertical relationship than the pretreatment radiograph. In the mandibular region, changes re-
suiting in improvement in symmetry were noted as the rightside effective mandibular length, ramal height, and body length were reduced. In the anteroposterior relationships, the mandibular chin position was decreased by I mm, and the facial angle and SNB measurements were decreased by 1.5 ° and 4.5 °, respectively. Mandibular plane measurement did not change throughout treatment.
Volume 99 Number 3
Case report
201
Fig. 15, Age 21 yr. 6 mo. Retention model photographs.
SUMMARY After 3V2 years of posttreatment retention, the occlusion remained stable, and a very satisfactory result had been achieved. The facial skeletal and dental structures appeared to be in a more balanced relationship as the asymmetries described are much less pronounced than before treatment (Fig. 15). The patient is now being fitted with a maxillary lateral incisor-to-lateral
incisor lingual bonded retainer; mandibular retention will be removed within 3 months, at which time the patient will be recalled z/t 6-month intervals to check the stability of the result. Reprint requests to:
Dr. Robert W. Baker 412 N. Tioga St. Ithaca, NY 14850
