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Superior repositioning of the maxilla: Stability and soft tissue osseous relations
Superior repositioning of the maxilla: Stability and soft tissue osseous relations Stephen William
A. Schendel, D.D.S.,* Jerome H. Eirenfeld, and Bruce N. Epker, H. Bell, D.D.S.,***
Ph.D.,** D.D.S., Ph.D.****
Dallas, Texas
T
here is a group of vertical dysplasias that would be optimally COPrected, esthetically and functionally, by superior repositioning of the maxilla.‘W7 When this surgery is properly executed and combined with orthodontic treatment, an excellent esthetic and functional correction of the basic dentoskeletal deformity is attained. 2 ,8, 9, lopI1 Despite the early promising clinical results, the stability and esthetic relationships of such surgery have been incompletely evaluated to date. In 1974, skeletal stability was shown after five simultaneous anterior and posterior maxillary osteotomies for superior movement of the maxilla.” In an analysis of 106 Le Fort I ostetotomies, Willmar demonstrated very little postoperative change in the position of the maxilla. Only three of these patients, however, were treated by superior repositioning of the maxilla. The purpose of the present study was to evaluate the stability and soft-tissucosseous relations associated with superior repositioning of the maxilla by total maxillary osteotomy or combined anterior and posterior maxillary osteotomies. A new computer morphometiic analysis was used to evaluate a group of patients who were treated in this manner. The research supported in part by HEW Grant versity of Texas at Arlington organized Research *Oral
Surgery
Resident,
Parkland
Memorial
**Associate Professor of Mathematics, The ing Associate Professor of Medical Computer western Medical School. ***Associate Professor, partment of Surgery, Facial Deformities. ***“Director, Dento-Facial
Oral and Deformities,
3794-04 681.
and
by The
Uni-
Hospital. University Science,
The University of Texas Division of Oral Surgery, Maxillo-Facial John Peter
No. DE0 Grant No.
of Texas at Arlington, The University of Texas
Southwestern Center for
Surgery and Smith Hospital.
Center
Medical Correction for
the
VisitSouth-
School, Deof DentoTreatment
of
663
664
Schendel et al.
Table
I. Patient
population Mean
Diagnosis
age fyr.1
No.
Am. J. Orthod.
December
summary
Age range hr.)
A vg. folio w-up (m0.l
Follow-up range (mo.)
Vertical 24 20 13-33 13.8 4-29 maxillary excess Bimaxillary 6 20 12-37 14.7 4-20 protrusion *Total maxillary osteotomy (Le Fort I osteotomy). tSimultaneous anterior and posterior maxillary osteotomies. Table
II.
Vertical
maxillary
Angular and linear measurements’
SNA (degrees) SNB (degrees) ANB (degrees) MP-SN (degrees) PP-SN (degrees) OP-SN (degrees) I-NA (degrees) I-MP (degrees) TFH (mm.) UFH (mm.) LFH (mm.) PFH (mm.) Overbite (mm.) Upper lip thickness, A-A’* *Al=Soft tissue equivalent Methods
and
1976
excess-cephalometric
Pre-or postop. ortho.
Total* max.
A-Pf max.
16
13
11
13
5
0
0
6
values
Preoperative Value
79.14 71.76 7.38 44.20 6.08 16.83 26.90 90.25 121.63 52.98 68.65 75.98 6.245 14.27 to A point.
Surgery
Preop. open bite
Postoperative S.D.
3.67 4.26 3.47 9.75 3.70 6.06 7.77 5.72 8.91 4.07 7.47 8.87 3.86 2.16
Value
76.10 73.71 2.39 39.85 7.12 18.01 26.22 93.24 116.395 49.60 66.78 73.71 3.59 15.57
S.D.
3.91 4.17 3.59 7.20 7.57 6.42 9.03 5.14 7.66 4.71 5.30 7.57 1.70 2.65
materials
Records of thirty patients treated by superior repositioning of the total maxilla were obtained from the dentofacial deformity records of Parkland and John Peter Smith hospitals. The patient population included six black patients with bimaxillary protrusion and twenty-four white patients who were classified as having vertical maxillary excess (VME) Table I), Mean recall follow-up was slightly in excess of 14 months. The longest postoperative follow-up was 29 months. Preoperative, immediate postoperative (within the first 10 days postoperative) , and recall cephalometric roentgenographs used for soft-tissue analysis were taken with the patient’s lips in repose.14 The computerized craniofacial model of Walker was altered and added to his separate soft-tissue profile model. 15-17This created a model of 180 points (Fig. 1) which was fed into a DEC Systems-10 computer by the following method. A tracing was made of each cephalometric lateral roentgenograph. The cephalometric tracing was placed on a flat grid and each point entered by a sonic digitizer pen
Superior
Fig. 1. A 180-point
craniofacial
repositioning
of maxilla
665
model.
connected to a CRT terminal.# The coordinates of each point were then computed with respect to a new set of axes (S-N being horizontal, nasion = origin) which was standard for all patients. The anatomic points could then be connected and displayed on a CRT unit and photographed or plotted on paper for each cephalometric roentgenograph entered .* Averaged faces created from the thirty individuals under study were plotted by averaging the X and Y axis of each of the 180 points and then plotting the face. Metric measurements derived from this by the computer were average measurements. For the purpose of analysis, the patients were divided into two separate groups : vertical maxillary excess and bimaxillary protrusion. Averaged faces were calculated preoperatively, immediately postoperatively, and according t,o the latest recall cephalometric roentgenograph. All cephalometric drawings were superimposed on S-N and the anterior cranial base. For soft-tissue changes occurring with dento-osseous surgery, the preoperative and recall averaged faces were compared. In analyzing stability, the immediate postoperative and recall averaged faces were compared. Stability in the vertical maxillary excess populace was also analyzed separately for patients with preoperative open-bite and without open-bite. Metric values and standard deviations were derived directly from the computer and were oriented parallel or perpendicular to the S-N plane. *Calcomp
digital
drum
plotter
with
an II-inch
bed.
666
Schendel et 01.
Am.
J. Orthod.
Decembm-1976
Fig. 2. Computerized
average
presurgical
Fig. 3. Computerized
average
postsurgical
vertical
maxillary
vertical
maxillary
excess
excess
face.
face.
Averaged faces were created preoperatively, immediately postoperatively, and at recall for the twenty-four VME patients (Figs. 2 to 6) .* The averaged preoperative VME face is shown in Fig. 2 together with the significant values in “All computer retrognathic.
faces Divisions
are oriented with S-N of the square represent
horizontal in 1 cm. each.
the
square,
thus
appearing
slightly
Volwne
Superior
70
Number 6
of maxilln
repositioning
667
,
t,ll~~,,~llilll~‘~‘~L -100 Fig. 4. Composite soft-tissue-osseous
of presurgical and recall averaged changes in the vertical maxillary
6 computerized excess group.
faces
showing
surgical
Table II. Esthetic changes were evaluated in twenty-two patients. Two patients were not used because additional cosmetic surgery was completed before longterm records were obtained. The averaged face and postoperative values are shown in Fig. 3 and Table II. Postoperatively, osseous-soft-tissue changes were determined by superimposition of the averaged face preoperatively and at recall time (Fig. 4). On the average, the molar was moved superiorly 5.5 mm. and the incisor 5.69 mm. Arcordingly, the lower face height was shortened 5.24 mm. On the average, the maxillary incisor was moved posteriorly 2.80 mm. As a consequence, the upper lip moved posteriorly 2.13 mm. and superiorly 2.18 mm. The ratio of posterior movement of the upper lip to posterior movement of the maxillary incisor was 0.76 ; the ratio of superior movement of the upper lip to superior movement of the upper incisor was 0.38. A very high correlation coefficient of r = 0.767 was found between horizontal movement of the maxillary incisor and the vermilion border of the upper lip. The maxillary incisor also showed a correlation of r = 0.428 (horizontal) and r = 0.527 (vertical) with the vermilion border of the lower lip. Analysis of the total lip profile showed that there was essentially no change in contour, but a rotation around S point of the nose. In addition, the nasal tip was slightly raised by surgery. Because some of the VME patients also underwent concomitant mandibular surgery, a special face was formed to evaluate autorotation that excluded mandibular surgery. Fourteen VME patients who had no mandibular surgery were averaged to study autorotation of the mandible (Fig. 5). All osseous mandibular structures rotated on an arc with their origin at the condylar summit. Soft-tissue pogonion also rotated in the same arc in a 1: 1 ratio with the osseous pogonion. On inspcction, the lower lip from the mental fold upward did not fall on the arc. The t,rue
648
ScheTldel
et al.
Am. J. Orthod. December 19’76
1
0 0 -i
0
-100 Fig. 5. Mandibular demonstrate the incisal
tip,
(c) pogonion,
Fig. 6. Composite demonstrating
autorotation rotational path and
(d)
with superior repositioning of (u) mesial cusp mandibular lower
of immediate postsurgical skeletal
lip vermilion
postsurgical stability
in
of maxilla. first molar,
Compass arcs (b) mandibular
border.
and recall averaged the vertical maxillary
computerized excess
faces group.
lower lip VB was posterior on the X axis in a 1: 1 ratio with maxillary incisor retraction from the calculated autorotated point. Stability was examined in eighteen VME patients with complete records over an average follow-up period of 13.8 months. Averaged immediate postoperative and recall faces were superimposed (Fig. 5). Graphically, there was little move-
Superior Table
III. Vertical
maxillary
Measurements (mm.)*
Maxillary incisor (152) Maxillary first molar (160) A point (123) ANS (122)
excess-stability
Immediate
Recall S.D.
Y
of maxi2Za
669
measurements,
postoperative
S.D.
X
repositioning
Change
postoperative
X
S.D.
Y
SD.
x
Y
10.75
5.97
-79.14
7.28
-11.11
6.25
-78.81
6.99
-0.36
0.33
-39.31
6.39
-69.87
5.90
-39.58
5.94
-69.60
5.41
-0.27
0.27
-12.37 - IO.28
3.70 4.14
-53.63 -48.52
1.42 6.12
- 13.57 3.12 -10.73 3.37
-53.37 -48.79
6.49 5.62
-1.2 0.26 -0.45 -0.27
*Points located on X and Y axis are measured perpendicular or parallel to the SN line where nasion is the origin on the graph. Points located to the left of nasion on the X axis or below nasion on the Y axis are negative. Table
IV. Bimaxillary
protrusion-cephalometric
Angular and linear measurements
SNA (degrees) SNB (degrees) ANB (degrees) MP-SN (degrees) PP-SN (degrees) OP-SN (degrees) I-NA (degrees) IMP (mm.) TFH (mm.) UFH (mm.) LFH (mm.) PFH (mm.) Overbite (mm.) Upper lip thickness, A-A’* *Al=soft tissue equivalent
Average Value
82 76.11 6.64 45.33 4.80 18.44 28.77 102.93 123.73 51.74 71.99 72.68 - 1.89 14.85 to A point.
values
preoperative
Average S.D.
Value
3.36 2.41 3.90 5.15 4.76 2.38 9.81 9.04 6.98 6.23 4.11 4.04 3.72 2.96
81.51 76.44 5.07 39.69 6.62 23.55 19.31 99.05 119.94 51.03 68.92 73.03 1.80 14.20
postoperative SD.
3.51 2.06 4.45 3.44 2.72 5.59 8.44 6.04 4.58 3.59 2.29 4.30 2.48 2.39
ment after surgery. On metric evaluation, the molar cusp tip and the incisor showed minimal change whereas points ANS and A moved somewhat more (Table III). Independent analysis of the eleven preoperative open-bite patienm in this group revealed virtually no skeletal change. The six black patients with bimaxillary protrusion were also studied independently. Each of these patients also had simultaneous mandibular subapical surgery. The individual averaged face and average values preoperatively and at recall are shown in Figs, 7 and 8 and Table IV, respectively. By superimposing the faces, the osseous-soft-tissue changes were analyzed (Fig. 9). On the average, the molar was moved superiorly 4 mm. and the incisor 2.67 mm. As a consequence, the total face height was shortened 3.79 mm. As the maxillary incisor was moved posteriorly 6.10 mm., there was a 4.02 mm. posterior movement of the upper lip (VB) (ratio 0.66). In addition, the lip shortened 1.36 mm., a ratio of 0.51 between superior movement of the upper lip and superior movement of the incisor. The lip profile did not change but merely rotated around the area of subnasale to S point. The lower incisor moved posteriorly 2.92 mm. as the lower lip moved an
670
Schendel et al.
Am.
J. Orthod.
December1976
Fig. 7. Computerized
average
presurgical
bimaxillary
protrusion
face.
o--
0 o--1 I
-
I/II
I1llIIlII
0
-100 Fig. 8. Computerized
average
II111
postsurgical
bimaxillary
protrusion
face.
average of 3.64 mm. The relationship shown by these ratios is oversimplified. The number of patients with bimaxillary protrusion was too small for correlation and regression analysis as done with the VME patients. Five bimaxillary protrusion patients had complete records for evaluation of stability. Each of these patients had a preoperative open-bite. The superimposed averaged immediate postoperative and recall faces are shown in Fig. 10. Over an
Superior
Fig. 9. surgical
Composite of soft-tissue-osseous
presurgical and recall averaged changes in the bimaxillary
Table
V.
protrusion-stability
Bimaxillary
Measurements (mm.)*
Immediate x
S.D.
repositioning
of maxilla
computerized faces protrusion group.
671
demonstrating
measurements Recall
postoperative Y
S.D.
X
S.D.
postoperative Y
Change S.D.
X
Y
Maxillary incisor -4.56 2.91 -15.36 2.69 -4.39 3.12 -14.33 3.15 0.17 1.03 (152) Maxillary first -28.42 2.84 -13.92 2.08 -28.05 2.76 -72.66 2.95 0.37 1.26 molar (160) A point (123) -5.67 3.86 -72.41 2.55 -5.96 3.51 -71.19 3.53 -0.29 1.22 ANS (122) -1.89 5.05 -57.88 4.16 -8.81 4.26 -56.80 4.10 -0.92 1.08 *Points located on X and Y axis are measured perpendicular or parallel to the SN line where nasion is the origin on the graph. Points located to the left of nasion on the X axis or below nasion on the Y axis are negative.
average postoperative follow-up period of 14.7 months, there was virtually no change in the position of the maxilla. During the postoperative period the molar tip moved superiorly 1.26 mm. and the incisor tip 1.03 mm. (Table V) . Discussion
Improved surgical techniques that facilitate complete mobilization and passive repositioning of the maxilla have virtually eliminated the relapse that was SO commonly encountered by early users of maxillary surgery.8y g, la* I9 There was minimal postoperative movement of the maxilla over a 14-month period of follow-up. The small amount of postoperat,ive change was in the same direction as the maxilla was moved (Table III, V). ANS and A points demonstrated the greatest amount of postoperative change ; remodeling of ANS made identification
672
Schendel
et al.
Am.
J. Orthod.
December1976
L
E
Fig. 10. demonstrating
Composite of immediate postsurgical skeletal
postsurgical stability
in
and the
recall averaged computerized bimaxillary protrusion group.
faces
of A point difficult. Mandibular rotation that occurred between the immediate postoperative and recall radiographs was due to removal of the interocclusal acrylic splint used at surgery. Soft-tissue changes between immediate postoperative and recall roentgenographs were secondary to the resolution of postoperative swelling. Computer analysis of the surgical changes demonstrated autorotation of the mandible around the condylar head. The lower lip from the mental fold superiorly, however, did not fall on this arc. The vermilion border of the lower lip was posterior on the X axis on a 1: 1 ratio with the maxillary incisor retraction. This relationship is also reflected in the high correlation coefficients between maxillary incisor movement in the X and Y axis and lower lip movement in the X axis. Apparently the lip unfolds from the mental fold superiorly. The position is a combined function of mandibular autorotation, maxillary incisor retraction, and improved lip posture and tonicity. The same relationship is seen in the bimaxillary protrusion patients in whom the lower incisor was surgically retracted 2.92 mm. and the lower lip moved back 3.64 mm.; lower lip movement was greater than lower incisor movement. Horizontal movement of the upper lip correlates well with horizontal movement of the maxillary incisor (hvb/hi, r = 0.767). The ratio for this change is 0.76 in the VME group, which closely agrees with the figure of 0.7 ? 0.1 for clinical use described by Bell and DannZo for anterior maxillary setback. The smaller bimaxillary protrusion group ratio of 0.66 is in the above range and close to the two-thirds ratio other authors have stated.2i Graphically, the upper lip contour does not change but apparently rotates about S point in the VME population and subnasale in the bimaxillary protrusion group. There was a tendency for the upper lip to thicken with posterior movement (Table II).
Superior
reposition~ing
of maxilla
673
Despite the many methods that have been introduced for objective evaluation of the osseous structures and soft-tissue profile, none of them is totally satisfactory because they all aim at making the face conform to a specific predetermined standard. Evaluation of morphologic deformities and surgical-orthodontic correction is thus limited. Computerized morphometrics enables us to make a more sophisticated study of the craniofacial structures. Adaptation of Walker’s craniofacial model to study osseous and soft-tissue surgical changes has proved an invaluable and efficient method for analysis of large data bases. Unilateral and horizontal maxillary changes with and after surgery need to be more fully evaluated. EMIT and other muscular aspects associated with dentofacial deformities should be more clearly defined and the effect of surgery upon them studied. The tongue apparently did not affect skeletal stability but adapted to the surgically changed environment as stated by others.2n Further advances with computer morphometrics should further benefit analysis and treatment of dentofacial deformities. Summary
The skeletal stability and soft-tissue changes associated with superior repositioning of the maxilla by Le Fort I osteotomy or simultaneous anterior and posterior maxillary osteotomies was studied in thirty patients by means of a computerized craniofacial model. Excellent skeletal stability was demonstrated 13 months postoperatively. Postsurgically, the reduction in lower face height ant1 amount of maxillary incisor exposure resulted in improved facial balance. The use of a computerized osseous and soft-tissue craniofacial model has added a new dimension to evaluation of surgical changes associated with correction of dentofacial and craniofacial deformities. The authors are grateful to the staff of the Department of Cardiology, SouthwestrrxI Medical School, for allowing the use of their Craf Sonic Digitizer. The authors are indebted to Mr. David Barker, Dr. Richard Browne, and Mr. Kent Dan:t for computer programming and to Dr. Geoffrey Walker and Dr. David Mishelevich for thei: help in planning the study. They are also indebted to Mrs. Vicky Stinson for technical assistance in preparing the manuscript. REFERENCES
1. Schendel, S. A., Eisenfeld, J. H., Bell, W. H., Epker, B. N., and Mishelevich, D. : Th.: long face syndrome-Vertical maxillary excess, Ahd. J. ORTHOD. 70: 398-408, 1976. 2. West, R. A., and McNeill, R. N.: Maxillary alveolar hyperplasia, diagnosis, and treatment. planning, J. Max.-Fat. Surg. 3, 4: 239-249, 1975. 3. Subtelny, D. J., and Sakuda, M.: Open bite: Diagnosis and treatment, AM. J. ORTHOD. 50: 337-358, 1964. 4. Nahoum, H. I.: Anterior open bite: A cephalometric analysis and suggested treatment, procedures, AM. J. ORTHOD.~~: 513-521, 1975. 5. McNeill, R. N.: Skeletal relapse following intermaxillary fixation surgical mandibular advancements, Trans. Eur. Orthod. Sot. 361, 1973. 6. Macintosh, B. R., and Carlotti, E. 9.: Total mandibular alveolar osteotomy in the maw agement of skeletal (infantile) apertognathia, J. Oral Surg. 33: 921-928, 1975. 7. Hulsey, C. M.: An esthetic evaluation of lip-teeth relationships present in the smile, A%[. J. ORTHOD. 57: 132-144, 1970. 8. Bell, W. H.: Le Fort I osteotomy for correction of maxillary deformities, J. Oral Surg. 33: 412-426, 1975.
674
Schedel
ct al,
Am. J. Orthod. December 1976
9. Wolford, L. M., and Epker, B. N.: The combined anterior and posterior maxillary osteotomy, J. Oral Surg. 33: 842-851, 1975. IO. Hall, D. H., and Roddy, S. C.: Treatment of maxillary alveolar hyperplasia by total maxillary alveolar osteotomy, J. Oral Surg. 33: 180.189, 1975. II. Hall, D. H., and West, R. A.: Combined anterior and posterior maxillary osteotomy, J. Oral Surg. 34: 126-141, 1976. 12. Stoker, N. G., and Epker, B. N.: The posterior maxillary osteotomy: A retrospective study of treatment results, Int. J. Oral Surg. 3: 153-157, 1974. 13. Willmar, K.: On Le Fort I ostetotomy, Stand. J. Plast. Reconstr. Surg. Suppl. 12, 1974. 14. Burstone, C. J.: Lip posture and its significance in treatment planning, AM. J. ORTHOD. 53: 262 1967. 15. Walker,’ G. F., and Kowalski, C. J. : A two-dimensional coordinate model for the quantification, description, analysis, prediction, and simultation of craniofacial growth, Growth 35: 191-211, 1971. 16. Walker, G. F.: A new approach to the analysis of craniofacial morphology and growth, AM. J. ORTHOD. 61: 221-230, 1972. 17. Walker, G. F. : The computer and the law: Coordinate analysis of skull shape and possible methods of post-mortem identification, presented at 27th Annual Meeting of the American Academy of Forensic Sciences, Chicago, Feb. 18-21, 1975. 18. Schuchardt, K.: Experiences with the surgical treatment of deformities of the jaws: Prognathia, micrognathia, and open bite. In: Wallace, A. G., editor: Second Congress of International Society of Plastic Surgeons, London, 1959, E. & S. Livingstone. 19. Kufner, J.: Experience with a modified procedure for correction of open bite. In: Transactions of the Third International Conference of Oral Surgery, London, 1970, E. & S. Livingstone. 20. Bell, W. H., and Dann, J. J.: Correction of dento-facial deformities by surgery in the anterior part of the jaws, AM. J. ORTHOD. 64: 162, 1973. 21. Lines, P. A,, and Steinhauser, E. W.: Soft tissue changes in relation to movement of hard structures in orthognathic surgery: A preliminary report, J. Oral Surg. 32: 891, 1974.
A. Schendel, D.D.S.,* Jerome H. Eirenfeld, and Bruce N. Epker, H. Bell, D.D.S.,***
Ph.D.,** D.D.S., Ph.D.****
Dallas, Texas
T
here is a group of vertical dysplasias that would be optimally COPrected, esthetically and functionally, by superior repositioning of the maxilla.‘W7 When this surgery is properly executed and combined with orthodontic treatment, an excellent esthetic and functional correction of the basic dentoskeletal deformity is attained. 2 ,8, 9, lopI1 Despite the early promising clinical results, the stability and esthetic relationships of such surgery have been incompletely evaluated to date. In 1974, skeletal stability was shown after five simultaneous anterior and posterior maxillary osteotomies for superior movement of the maxilla.” In an analysis of 106 Le Fort I ostetotomies, Willmar demonstrated very little postoperative change in the position of the maxilla. Only three of these patients, however, were treated by superior repositioning of the maxilla. The purpose of the present study was to evaluate the stability and soft-tissucosseous relations associated with superior repositioning of the maxilla by total maxillary osteotomy or combined anterior and posterior maxillary osteotomies. A new computer morphometiic analysis was used to evaluate a group of patients who were treated in this manner. The research supported in part by HEW Grant versity of Texas at Arlington organized Research *Oral
Surgery
Resident,
Parkland
Memorial
**Associate Professor of Mathematics, The ing Associate Professor of Medical Computer western Medical School. ***Associate Professor, partment of Surgery, Facial Deformities. ***“Director, Dento-Facial
Oral and Deformities,
3794-04 681.
and
by The
Uni-
Hospital. University Science,
The University of Texas Division of Oral Surgery, Maxillo-Facial John Peter
No. DE0 Grant No.
of Texas at Arlington, The University of Texas
Southwestern Center for
Surgery and Smith Hospital.
Center
Medical Correction for
the
VisitSouth-
School, Deof DentoTreatment
of
663
664
Schendel et al.
Table
I. Patient
population Mean
Diagnosis
age fyr.1
No.
Am. J. Orthod.
December
summary
Age range hr.)
A vg. folio w-up (m0.l
Follow-up range (mo.)
Vertical 24 20 13-33 13.8 4-29 maxillary excess Bimaxillary 6 20 12-37 14.7 4-20 protrusion *Total maxillary osteotomy (Le Fort I osteotomy). tSimultaneous anterior and posterior maxillary osteotomies. Table
II.
Vertical
maxillary
Angular and linear measurements’
SNA (degrees) SNB (degrees) ANB (degrees) MP-SN (degrees) PP-SN (degrees) OP-SN (degrees) I-NA (degrees) I-MP (degrees) TFH (mm.) UFH (mm.) LFH (mm.) PFH (mm.) Overbite (mm.) Upper lip thickness, A-A’* *Al=Soft tissue equivalent Methods
and
1976
excess-cephalometric
Pre-or postop. ortho.
Total* max.
A-Pf max.
16
13
11
13
5
0
0
6
values
Preoperative Value
79.14 71.76 7.38 44.20 6.08 16.83 26.90 90.25 121.63 52.98 68.65 75.98 6.245 14.27 to A point.
Surgery
Preop. open bite
Postoperative S.D.
3.67 4.26 3.47 9.75 3.70 6.06 7.77 5.72 8.91 4.07 7.47 8.87 3.86 2.16
Value
76.10 73.71 2.39 39.85 7.12 18.01 26.22 93.24 116.395 49.60 66.78 73.71 3.59 15.57
S.D.
3.91 4.17 3.59 7.20 7.57 6.42 9.03 5.14 7.66 4.71 5.30 7.57 1.70 2.65
materials
Records of thirty patients treated by superior repositioning of the total maxilla were obtained from the dentofacial deformity records of Parkland and John Peter Smith hospitals. The patient population included six black patients with bimaxillary protrusion and twenty-four white patients who were classified as having vertical maxillary excess (VME) Table I), Mean recall follow-up was slightly in excess of 14 months. The longest postoperative follow-up was 29 months. Preoperative, immediate postoperative (within the first 10 days postoperative) , and recall cephalometric roentgenographs used for soft-tissue analysis were taken with the patient’s lips in repose.14 The computerized craniofacial model of Walker was altered and added to his separate soft-tissue profile model. 15-17This created a model of 180 points (Fig. 1) which was fed into a DEC Systems-10 computer by the following method. A tracing was made of each cephalometric lateral roentgenograph. The cephalometric tracing was placed on a flat grid and each point entered by a sonic digitizer pen
Superior
Fig. 1. A 180-point
craniofacial
repositioning
of maxilla
665
model.
connected to a CRT terminal.# The coordinates of each point were then computed with respect to a new set of axes (S-N being horizontal, nasion = origin) which was standard for all patients. The anatomic points could then be connected and displayed on a CRT unit and photographed or plotted on paper for each cephalometric roentgenograph entered .* Averaged faces created from the thirty individuals under study were plotted by averaging the X and Y axis of each of the 180 points and then plotting the face. Metric measurements derived from this by the computer were average measurements. For the purpose of analysis, the patients were divided into two separate groups : vertical maxillary excess and bimaxillary protrusion. Averaged faces were calculated preoperatively, immediately postoperatively, and according t,o the latest recall cephalometric roentgenograph. All cephalometric drawings were superimposed on S-N and the anterior cranial base. For soft-tissue changes occurring with dento-osseous surgery, the preoperative and recall averaged faces were compared. In analyzing stability, the immediate postoperative and recall averaged faces were compared. Stability in the vertical maxillary excess populace was also analyzed separately for patients with preoperative open-bite and without open-bite. Metric values and standard deviations were derived directly from the computer and were oriented parallel or perpendicular to the S-N plane. *Calcomp
digital
drum
plotter
with
an II-inch
bed.
666
Schendel et 01.
Am.
J. Orthod.
Decembm-1976
Fig. 2. Computerized
average
presurgical
Fig. 3. Computerized
average
postsurgical
vertical
maxillary
vertical
maxillary
excess
excess
face.
face.
Averaged faces were created preoperatively, immediately postoperatively, and at recall for the twenty-four VME patients (Figs. 2 to 6) .* The averaged preoperative VME face is shown in Fig. 2 together with the significant values in “All computer retrognathic.
faces Divisions
are oriented with S-N of the square represent
horizontal in 1 cm. each.
the
square,
thus
appearing
slightly
Volwne
Superior
70
Number 6
of maxilln
repositioning
667
,
t,ll~~,,~llilll~‘~‘~L -100 Fig. 4. Composite soft-tissue-osseous
of presurgical and recall averaged changes in the vertical maxillary
6 computerized excess group.
faces
showing
surgical
Table II. Esthetic changes were evaluated in twenty-two patients. Two patients were not used because additional cosmetic surgery was completed before longterm records were obtained. The averaged face and postoperative values are shown in Fig. 3 and Table II. Postoperatively, osseous-soft-tissue changes were determined by superimposition of the averaged face preoperatively and at recall time (Fig. 4). On the average, the molar was moved superiorly 5.5 mm. and the incisor 5.69 mm. Arcordingly, the lower face height was shortened 5.24 mm. On the average, the maxillary incisor was moved posteriorly 2.80 mm. As a consequence, the upper lip moved posteriorly 2.13 mm. and superiorly 2.18 mm. The ratio of posterior movement of the upper lip to posterior movement of the maxillary incisor was 0.76 ; the ratio of superior movement of the upper lip to superior movement of the upper incisor was 0.38. A very high correlation coefficient of r = 0.767 was found between horizontal movement of the maxillary incisor and the vermilion border of the upper lip. The maxillary incisor also showed a correlation of r = 0.428 (horizontal) and r = 0.527 (vertical) with the vermilion border of the lower lip. Analysis of the total lip profile showed that there was essentially no change in contour, but a rotation around S point of the nose. In addition, the nasal tip was slightly raised by surgery. Because some of the VME patients also underwent concomitant mandibular surgery, a special face was formed to evaluate autorotation that excluded mandibular surgery. Fourteen VME patients who had no mandibular surgery were averaged to study autorotation of the mandible (Fig. 5). All osseous mandibular structures rotated on an arc with their origin at the condylar summit. Soft-tissue pogonion also rotated in the same arc in a 1: 1 ratio with the osseous pogonion. On inspcction, the lower lip from the mental fold upward did not fall on the arc. The t,rue
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1
0 0 -i
0
-100 Fig. 5. Mandibular demonstrate the incisal
tip,
(c) pogonion,
Fig. 6. Composite demonstrating
autorotation rotational path and
(d)
with superior repositioning of (u) mesial cusp mandibular lower
of immediate postsurgical skeletal
lip vermilion
postsurgical stability
in
of maxilla. first molar,
Compass arcs (b) mandibular
border.
and recall averaged the vertical maxillary
computerized excess
faces group.
lower lip VB was posterior on the X axis in a 1: 1 ratio with maxillary incisor retraction from the calculated autorotated point. Stability was examined in eighteen VME patients with complete records over an average follow-up period of 13.8 months. Averaged immediate postoperative and recall faces were superimposed (Fig. 5). Graphically, there was little move-
Superior Table
III. Vertical
maxillary
Measurements (mm.)*
Maxillary incisor (152) Maxillary first molar (160) A point (123) ANS (122)
excess-stability
Immediate
Recall S.D.
Y
of maxi2Za
669
measurements,
postoperative
S.D.
X
repositioning
Change
postoperative
X
S.D.
Y
SD.
x
Y
10.75
5.97
-79.14
7.28
-11.11
6.25
-78.81
6.99
-0.36
0.33
-39.31
6.39
-69.87
5.90
-39.58
5.94
-69.60
5.41
-0.27
0.27
-12.37 - IO.28
3.70 4.14
-53.63 -48.52
1.42 6.12
- 13.57 3.12 -10.73 3.37
-53.37 -48.79
6.49 5.62
-1.2 0.26 -0.45 -0.27
*Points located on X and Y axis are measured perpendicular or parallel to the SN line where nasion is the origin on the graph. Points located to the left of nasion on the X axis or below nasion on the Y axis are negative. Table
IV. Bimaxillary
protrusion-cephalometric
Angular and linear measurements
SNA (degrees) SNB (degrees) ANB (degrees) MP-SN (degrees) PP-SN (degrees) OP-SN (degrees) I-NA (degrees) IMP (mm.) TFH (mm.) UFH (mm.) LFH (mm.) PFH (mm.) Overbite (mm.) Upper lip thickness, A-A’* *Al=soft tissue equivalent
Average Value
82 76.11 6.64 45.33 4.80 18.44 28.77 102.93 123.73 51.74 71.99 72.68 - 1.89 14.85 to A point.
values
preoperative
Average S.D.
Value
3.36 2.41 3.90 5.15 4.76 2.38 9.81 9.04 6.98 6.23 4.11 4.04 3.72 2.96
81.51 76.44 5.07 39.69 6.62 23.55 19.31 99.05 119.94 51.03 68.92 73.03 1.80 14.20
postoperative SD.
3.51 2.06 4.45 3.44 2.72 5.59 8.44 6.04 4.58 3.59 2.29 4.30 2.48 2.39
ment after surgery. On metric evaluation, the molar cusp tip and the incisor showed minimal change whereas points ANS and A moved somewhat more (Table III). Independent analysis of the eleven preoperative open-bite patienm in this group revealed virtually no skeletal change. The six black patients with bimaxillary protrusion were also studied independently. Each of these patients also had simultaneous mandibular subapical surgery. The individual averaged face and average values preoperatively and at recall are shown in Figs, 7 and 8 and Table IV, respectively. By superimposing the faces, the osseous-soft-tissue changes were analyzed (Fig. 9). On the average, the molar was moved superiorly 4 mm. and the incisor 2.67 mm. As a consequence, the total face height was shortened 3.79 mm. As the maxillary incisor was moved posteriorly 6.10 mm., there was a 4.02 mm. posterior movement of the upper lip (VB) (ratio 0.66). In addition, the lip shortened 1.36 mm., a ratio of 0.51 between superior movement of the upper lip and superior movement of the incisor. The lip profile did not change but merely rotated around the area of subnasale to S point. The lower incisor moved posteriorly 2.92 mm. as the lower lip moved an
670
Schendel et al.
Am.
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December1976
Fig. 7. Computerized
average
presurgical
bimaxillary
protrusion
face.
o--
0 o--1 I
-
I/II
I1llIIlII
0
-100 Fig. 8. Computerized
average
II111
postsurgical
bimaxillary
protrusion
face.
average of 3.64 mm. The relationship shown by these ratios is oversimplified. The number of patients with bimaxillary protrusion was too small for correlation and regression analysis as done with the VME patients. Five bimaxillary protrusion patients had complete records for evaluation of stability. Each of these patients had a preoperative open-bite. The superimposed averaged immediate postoperative and recall faces are shown in Fig. 10. Over an
Superior
Fig. 9. surgical
Composite of soft-tissue-osseous
presurgical and recall averaged changes in the bimaxillary
Table
V.
protrusion-stability
Bimaxillary
Measurements (mm.)*
Immediate x
S.D.
repositioning
of maxilla
computerized faces protrusion group.
671
demonstrating
measurements Recall
postoperative Y
S.D.
X
S.D.
postoperative Y
Change S.D.
X
Y
Maxillary incisor -4.56 2.91 -15.36 2.69 -4.39 3.12 -14.33 3.15 0.17 1.03 (152) Maxillary first -28.42 2.84 -13.92 2.08 -28.05 2.76 -72.66 2.95 0.37 1.26 molar (160) A point (123) -5.67 3.86 -72.41 2.55 -5.96 3.51 -71.19 3.53 -0.29 1.22 ANS (122) -1.89 5.05 -57.88 4.16 -8.81 4.26 -56.80 4.10 -0.92 1.08 *Points located on X and Y axis are measured perpendicular or parallel to the SN line where nasion is the origin on the graph. Points located to the left of nasion on the X axis or below nasion on the Y axis are negative.
average postoperative follow-up period of 14.7 months, there was virtually no change in the position of the maxilla. During the postoperative period the molar tip moved superiorly 1.26 mm. and the incisor tip 1.03 mm. (Table V) . Discussion
Improved surgical techniques that facilitate complete mobilization and passive repositioning of the maxilla have virtually eliminated the relapse that was SO commonly encountered by early users of maxillary surgery.8y g, la* I9 There was minimal postoperative movement of the maxilla over a 14-month period of follow-up. The small amount of postoperat,ive change was in the same direction as the maxilla was moved (Table III, V). ANS and A points demonstrated the greatest amount of postoperative change ; remodeling of ANS made identification
672
Schendel
et al.
Am.
J. Orthod.
December1976
L
E
Fig. 10. demonstrating
Composite of immediate postsurgical skeletal
postsurgical stability
in
and the
recall averaged computerized bimaxillary protrusion group.
faces
of A point difficult. Mandibular rotation that occurred between the immediate postoperative and recall radiographs was due to removal of the interocclusal acrylic splint used at surgery. Soft-tissue changes between immediate postoperative and recall roentgenographs were secondary to the resolution of postoperative swelling. Computer analysis of the surgical changes demonstrated autorotation of the mandible around the condylar head. The lower lip from the mental fold superiorly, however, did not fall on this arc. The vermilion border of the lower lip was posterior on the X axis on a 1: 1 ratio with the maxillary incisor retraction. This relationship is also reflected in the high correlation coefficients between maxillary incisor movement in the X and Y axis and lower lip movement in the X axis. Apparently the lip unfolds from the mental fold superiorly. The position is a combined function of mandibular autorotation, maxillary incisor retraction, and improved lip posture and tonicity. The same relationship is seen in the bimaxillary protrusion patients in whom the lower incisor was surgically retracted 2.92 mm. and the lower lip moved back 3.64 mm.; lower lip movement was greater than lower incisor movement. Horizontal movement of the upper lip correlates well with horizontal movement of the maxillary incisor (hvb/hi, r = 0.767). The ratio for this change is 0.76 in the VME group, which closely agrees with the figure of 0.7 ? 0.1 for clinical use described by Bell and DannZo for anterior maxillary setback. The smaller bimaxillary protrusion group ratio of 0.66 is in the above range and close to the two-thirds ratio other authors have stated.2i Graphically, the upper lip contour does not change but apparently rotates about S point in the VME population and subnasale in the bimaxillary protrusion group. There was a tendency for the upper lip to thicken with posterior movement (Table II).
Superior
reposition~ing
of maxilla
673
Despite the many methods that have been introduced for objective evaluation of the osseous structures and soft-tissue profile, none of them is totally satisfactory because they all aim at making the face conform to a specific predetermined standard. Evaluation of morphologic deformities and surgical-orthodontic correction is thus limited. Computerized morphometrics enables us to make a more sophisticated study of the craniofacial structures. Adaptation of Walker’s craniofacial model to study osseous and soft-tissue surgical changes has proved an invaluable and efficient method for analysis of large data bases. Unilateral and horizontal maxillary changes with and after surgery need to be more fully evaluated. EMIT and other muscular aspects associated with dentofacial deformities should be more clearly defined and the effect of surgery upon them studied. The tongue apparently did not affect skeletal stability but adapted to the surgically changed environment as stated by others.2n Further advances with computer morphometrics should further benefit analysis and treatment of dentofacial deformities. Summary
The skeletal stability and soft-tissue changes associated with superior repositioning of the maxilla by Le Fort I osteotomy or simultaneous anterior and posterior maxillary osteotomies was studied in thirty patients by means of a computerized craniofacial model. Excellent skeletal stability was demonstrated 13 months postoperatively. Postsurgically, the reduction in lower face height ant1 amount of maxillary incisor exposure resulted in improved facial balance. The use of a computerized osseous and soft-tissue craniofacial model has added a new dimension to evaluation of surgical changes associated with correction of dentofacial and craniofacial deformities. The authors are grateful to the staff of the Department of Cardiology, SouthwestrrxI Medical School, for allowing the use of their Craf Sonic Digitizer. The authors are indebted to Mr. David Barker, Dr. Richard Browne, and Mr. Kent Dan:t for computer programming and to Dr. Geoffrey Walker and Dr. David Mishelevich for thei: help in planning the study. They are also indebted to Mrs. Vicky Stinson for technical assistance in preparing the manuscript. REFERENCES
1. Schendel, S. A., Eisenfeld, J. H., Bell, W. H., Epker, B. N., and Mishelevich, D. : Th.: long face syndrome-Vertical maxillary excess, Ahd. J. ORTHOD. 70: 398-408, 1976. 2. West, R. A., and McNeill, R. N.: Maxillary alveolar hyperplasia, diagnosis, and treatment. planning, J. Max.-Fat. Surg. 3, 4: 239-249, 1975. 3. Subtelny, D. J., and Sakuda, M.: Open bite: Diagnosis and treatment, AM. J. ORTHOD. 50: 337-358, 1964. 4. Nahoum, H. I.: Anterior open bite: A cephalometric analysis and suggested treatment, procedures, AM. J. ORTHOD.~~: 513-521, 1975. 5. McNeill, R. N.: Skeletal relapse following intermaxillary fixation surgical mandibular advancements, Trans. Eur. Orthod. Sot. 361, 1973. 6. Macintosh, B. R., and Carlotti, E. 9.: Total mandibular alveolar osteotomy in the maw agement of skeletal (infantile) apertognathia, J. Oral Surg. 33: 921-928, 1975. 7. Hulsey, C. M.: An esthetic evaluation of lip-teeth relationships present in the smile, A%[. J. ORTHOD. 57: 132-144, 1970. 8. Bell, W. H.: Le Fort I osteotomy for correction of maxillary deformities, J. Oral Surg. 33: 412-426, 1975.
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9. Wolford, L. M., and Epker, B. N.: The combined anterior and posterior maxillary osteotomy, J. Oral Surg. 33: 842-851, 1975. IO. Hall, D. H., and Roddy, S. C.: Treatment of maxillary alveolar hyperplasia by total maxillary alveolar osteotomy, J. Oral Surg. 33: 180.189, 1975. II. Hall, D. H., and West, R. A.: Combined anterior and posterior maxillary osteotomy, J. Oral Surg. 34: 126-141, 1976. 12. Stoker, N. G., and Epker, B. N.: The posterior maxillary osteotomy: A retrospective study of treatment results, Int. J. Oral Surg. 3: 153-157, 1974. 13. Willmar, K.: On Le Fort I ostetotomy, Stand. J. Plast. Reconstr. Surg. Suppl. 12, 1974. 14. Burstone, C. J.: Lip posture and its significance in treatment planning, AM. J. ORTHOD. 53: 262 1967. 15. Walker,’ G. F., and Kowalski, C. J. : A two-dimensional coordinate model for the quantification, description, analysis, prediction, and simultation of craniofacial growth, Growth 35: 191-211, 1971. 16. Walker, G. F.: A new approach to the analysis of craniofacial morphology and growth, AM. J. ORTHOD. 61: 221-230, 1972. 17. Walker, G. F. : The computer and the law: Coordinate analysis of skull shape and possible methods of post-mortem identification, presented at 27th Annual Meeting of the American Academy of Forensic Sciences, Chicago, Feb. 18-21, 1975. 18. Schuchardt, K.: Experiences with the surgical treatment of deformities of the jaws: Prognathia, micrognathia, and open bite. In: Wallace, A. G., editor: Second Congress of International Society of Plastic Surgeons, London, 1959, E. & S. Livingstone. 19. Kufner, J.: Experience with a modified procedure for correction of open bite. In: Transactions of the Third International Conference of Oral Surgery, London, 1970, E. & S. Livingstone. 20. Bell, W. H., and Dann, J. J.: Correction of dento-facial deformities by surgery in the anterior part of the jaws, AM. J. ORTHOD. 64: 162, 1973. 21. Lines, P. A,, and Steinhauser, E. W.: Soft tissue changes in relation to movement of hard structures in orthognathic surgery: A preliminary report, J. Oral Surg. 32: 891, 1974.