Prediction of maxillary repositioning in lefort 1 surgery /certified fixed orthodontic courses by Indian dental academy

“PREDICTABILITY OF MAXILLARY
REPOSITIONING AND THE UPPER LIP
RESPONSE IN MAXILLARY LEFORT I
OSTEOTOMIES.”
-A CEPHALOMETRIC STUDY.

INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com


INTRODUCTION


• For
more
than
three
decades, orthognathic surgery has
proved to be a significant tool in
correcting severe dentofacial skeletal
discrepancies.
• The success of surgical orthodontic
therapy, is determined by factors such
as function, stability and esthetics.

• Defining ideal esthetic results is very
subjective and may be viewed differently by
the clinician and the patient.
• Patients who have viewed prediction
outcomes prior to treatment are more likely to
be satisfied with the outcome than those who
did not, also patients feel grateful for being
empowered and involved in planning their
treatment

• It is important to achieve an optimal profile
change which requires a correct balance of
midfacial dentoskeletal structures and soft
tissue contour.
• It would be necessary to be able to
predict, reliably and accurately, the changes
in the skeletal and soft tissues, which would
occur by a maxillary surgery.

• The final soft tissue profile of the lips is
of particular importance because when
asked to evaluate esthetics of life-sized
lateral photographs, laymen place more
emphasis on postoperative changes in
the lips than on the nose or the chin.


• Therefore an attempt is made here to
study the reliability of the predictions of
hard tissues in Maxillary LeFort I
Osteotomies, and assessing the
changes in the upper lip related to
these surgeries.


Aims and Objectives


1.

To compare the pre-surgical predictions and the
actual

changes

in

the

midface

dentoskeletal

structure, after a Maxillary Le-Fort I osteotomy.
2.

To predict the upper lip response to a Maxillary LeFort I osteotomy.


Materials and Method


• Pre-surgical and post-surgical (two months
following surgery) lateral cephalograms of
11 adult patients
• The age group of these patients ranged from
14 to 23 years.
• Treated by a Pre-adjusted Edgewise
appliance for pre-surgical decompensation.
• Maxillary Le-Fort I osteotomy was carried out
under the supervision of a single surgeon.

• 0.003 inch acetate tracing paper.
• 0.3 mm lead pencil.
• Geometry box (scale, protractor, set
squares, eraser).
• Scotch tapes.
• Tracing board.
• Scissors and calculator.

Primary Criterions For
Selection Of Patients
1.Patients who were treated by Maxillary
Le-fort
I
advancement/impaction
osteotomy with rigid fixation.
2.Patients had completed their growth
phase of maximum growth.
3.No concomitant or previous nasal
surgery.

4. No history of oral clefting.
5. No previous trauma to the midface.
6. Presurgical
and
cephalograms
were
standardized technique.


postsurgical
taken
by

HARD TISSUE VERTICAL
CHANGES (Fig. 2)

Na

S

S-Na + 7

PNS

A

ANS

UM
Is


S-Na + 7 To
PNS
Upper Molar
Point A
Point Is
Point ANS

HARD TISSUE HORIZONTAL
CHANGES (Fig. 3)

Na

S

S-Na + 7

PNS

A

ANS

UM
Is

Perpendicular of S-Na + 7 To
PNS
Upper Molar
Point A
Point Is
Point ANS

HARD TISSUE ANGULAR
CHANGES (Fig. 4)
Na
S

PNS
ANS
A

Sella Nasion to Nasion Point A
Sella Nasion to Palatal Plane


UPPER LIP RESPONSE (Fig. 5)

ANS
10
UL

UL

0

A
75

Sn
SLS

Pro
UL

Ia

50
UL 25

STO

ANS-SN
A-SLS
Pr-LS
Ia-LS
Sn-STO
LIPLT


LS
0
UL

CEPHALOMETRIC PREDICTION TRACING FOR
SUPERIOR REPOSITIONING OF MAXILLA AS
PER FISH AND EPKER

STEP – 1

STEP – 2

STEP – 3

STEP – 5
STEP
www.indiandentalacademy.com – 6

STEP – 4

PRE TREATMENT

PRE SURGICAL

MAXILLARY LE-FORT I PROCEDURE

Le-Fort I Osteotomy Cuts

Plated Maxillary Segment

Incision Sutured With
Splint in Place


POST TREATMENT

RESULTS


RELIABILITY OF
PREDICTION
• This part of the study comprised of two
angular, five vertical and five horizontal
measurements.
• For these measurements “Wilcoxons
signed rank test” was done and the P
value was determined to find if the
prediction was significantly accurate.

Graph 2

Sn +7 TO PALATAL PLANE ANGLE (Degrees)
3.5
3.5

Graph 1
82

ANGLE SNA (Degrees)
81.3
81.2

81

2.5

Pre
Surgical
Predicted

80

2

79
78

2.7

3

1.6

Post
Treatment

1.5
Post
Treatment

77.6

1

77

0.5

76

0
Pre Surgical

Predicted

Post Treatment

75
Pre Surgical

Predicted

Post Treatment

Graph 2

Sn +7 TO PALATAL PLANE ANGLE (Degrees)
3.5
3.5

Parameters
2.7

3
2.5
2

1.6
SNA

1.5
1
0.5

Sn+7 to Palatal
Plane

0
Pre Surgical

Predicted

P

Significance

0.82

NS

0.11

NS

Pre
Surgical
Predicted
Post
Treatment

Post Treatment

Pre
Surgical
Predicted

Graph 4
Graph 3
70

POINT A HORIZONTAL (mm)
69.9
69.4

72.5
72

Pre
Surgical
Predicted

71.5

69

Pre
Surgical
Predicted

68

71
70.5

67
66

POINT ANS HORIZONTAL (mm)
72.2
72.1

70

65.7

Post
Treatment

Post
Treatment

69.5

69.5
69

65

68.5

64

68
Pre Surgical

Predicted

Post Treatment

63
Pre Surgical

Predicted

Post Treatment

Graph 4
72.5

POINT ANS HORIZONTAL (mm)
72.2
72.1

72
71.5

Parameters

71
70.5
70

69.5

69.5

Point A
ANS

69

Pre
Surgical
Predicted

P

Significance

Post
Treatment

0.21

NS

0.86

NS

68.5
68
Pre Surgical

Predicted

Post Treatment

Graph 6
Graph 5
20

POINT PNS HORIZONTAL (mm)
19.9
19.7

19.5

UPPER INCISOR HORIZONTAL (mm)
73.2
72.9

73
Pre
Surgical
Predicted

19
18.5

74

Pre
Surgical
Predicted

72
71

Post
Treatment

69.7

70
Post
Treatment 69

18

18

68
17.5

67
Pre Surgical

Predicted

Post Treatment

17
Pre Surgical

Predicted

Post Treatment

Graph 6
74

UPPER INCISOR HORIZONTAL (mm)
73.2
72.9

73
72

70
69
68

Significance
NS

0.41

NS

Post
Treatment

69.7

PNS
UPPER INCISOR

67
Pre Surgical

P

0.77

Parameters

71

Pre
Surgical
Predicted

Predicted

Post Treatment www.indiandentalacademy.com

Graph 7

UPPER FIRST MOLAR HORIZONTAL (mm)
48
47.4
46.4
47
Pre
Surgical
Predicted

46
45

43.1

44

Post
Treatment

43
42
41
40
Pre Surgical

Predicted

Post Treatment

Parameters

P

Significance

UPPER 1ST MOLAR

0.25

NS


Graph 9
Graph 8
50

POINT A VERTICAL (mm)
49.5

45.5

POINT ANS VERTICAL (mm)
45.2

45
Pre
Surgical
Predicted

44.5
49

Pre
Surgical
Predicted

48

46.3

47

45.8

Post
Treatment

46

44
43.5

42.9

43

Post
Treatment

42.1

42.5
42
41.5

45

41
44

40.5
Pre Surgical

Predicted

Post Treatment

43
Pre Surgical

Predicted

Post Treatment

Graph 9
45.5

POINT ANS VERTICAL (mm)
45.2

45
44.5
44

42.5

42.9

Point A
42.1

42
41.5

ANS

P

Significance

0.09

NS

0.04

Parameters

43.5
43

Pre
Surgical
Predicted

S

Post
Treatment

41
40.5
Pre Surgical

Predicted

Post Treatment

Graph 11
Graph 10
42.5

POINT PNS VERTICAL (mm)
42.2

76

UPPER INCISOR VERTICAL (mm)
75.3

75

Pre
Surgical
Predicted

42

Pre
Surgical
Predicted

41.5
41

40.1

40.5

73
72

Post
Treatment

39.5

40

74

71.3

71.2

71

39.5

70

39

69

38.5

Pre Surgical

Predicted

Post Treatment

38
Pre Surgical

Predicted

Post Treatment

Graph 11
76
75

UPPER INCISOR VERTICAL (mm)
75.3

Parameters

Pre
Surgical
Predicted

74
73

PNS

72
71

71.2

71.3

UPPER INCISOR

Post
Treatment

P

Significance

0.1

NS

1

NS

70
69
Pre Surgical

Predicted

Post Treatmentwww.indiandentalacademy.com

Post
Treatment

Graph 12
69

UPPER FIRST MOLAR VERTICAL (mm)
68.5

68
67

66.2

Pre
Surgical
Predicted

66

64.7

65

Post
Treatment

64
63
62
Pre Surgical

Predicted

Post Treatment

P

Parameters
UPPER 1ST MOLAR

Significance

0.003

S


UPPER LIP
RESPONSE
• The change in the upper lip morphology was
correlated using the soft tissue measurements of
pre and post surgical tracings.
• Pearson’s correlation coefficient was calculated to
assess the nature and degree of the relation.
Linear regression analysis was then carried out to
predict the changes in the soft tissue
measurements for the changes carried out in the
hard tissue measurements.

• There were a total of twelve
correlations of the thickness of the lip to
the various hard tissue measurements
and six correlations of the length of the
lip to the various hard tissue
measurements.


Y

Pt. A

Predicted Y

LIP THICKNESS CHANGE
Graph 14

Graph 13

PREDICTION OF A-SLS FROM POINT A

PREDICTION OF ANS-Sn FROM POINT A

8.0

12
10

6.0
8
6

4.0

A-SLS

2
0
0

1

2

3

4

5

6

7

8

9

2.0
0.0

-2

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

-2.0

-4
-6

-4.0
-8
-10

-6.0
Y

Pt. A

Y

Pt. A

Predicted Y

Predicted Y

Graph 14

PREDICTION OF A-SLS FROM POINT A
Ratio
Parameters
8.0
Change

Pearson correlation
Coefficient (r-value)

Regression
Coefficient

-0.55

-0.92

6.0

Point A

4.0

A-SLS

ANS-Sn

4

2.0

2.3:1

ANS-Sn

0.0
0.0
-2.0
-4.0

1.0

2.0
Point3.0
A

A-SLS

4.0

5.0

6.0

7.0

8.0

9.0

02:01
-0.48

-0.06

Graph 15

PREDICTION OF Ia-Ls FROM POINT A
4.0
3.0
2.0
1.0

La- Ls

0.0
0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

-1.0
-2.0
-3.0
-4.0
-5.0

Y

-6.0

Parameters
Point A
Pro-LS

Predicted Y

Pt.A

Ratio
Change

Pearson correlation

Regression
Coefficient

3.6:1

-0.04

NS


Graph 16

Graph 17

PREDICTION OF ANS-Sn FROM POINT ANS

PREDICTION OF A-SLS FROM POINT ANS

12.0
8.0

10.0
8.0

6.0

6.0
4.0

2.0
0.0
-4.0

-2.0

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

-2.0

-4.0

-4.0

2.0

A-SLS

ANS-Sn

4.0

0.0
-2.0

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

-2.0

-6.0
-4.0

-8.0
-10.0

ANS

Y

-6.0

Y

Predicted Y

ANS

Predicted Y

Linear (Predicted Y)

Graph 17

Ratio
PREDICTION OF A-SLS FROM POINT ANS
Parameters
Change

Pearson correlation

Regression
Coefficient

-0.64

-0.53

-0.59

-0.36

8.0

ANS

6.0

4.0

ANS-Sn

2.0

A-SLS
-4.0

1.6:1

ANS

0.0
-2.0

0.0
-2.0

2.0

4.0

6.0

A-SLS

1.4:1

8.0

10.0

12.0

14.0

-4.0

Y

-6.0

ANS

Predicted Y
Linear (Predicted Y)

Graph 18

Graph 19

PREDICTION OF Pro-SLS FROM POINT ANS

PREDICTION OF Ia-LS FROM POINT ANS

8.0
7.0

4.0

6.0

3.0

5.0

2.0

3.0

Pro-SLS

4.0

1.0

2.0

0.0
La-LS

1.0
0.0
-4.0

-2.0

-1.0

0.0

2.0

4.0

6.0

8.0

10.0

12.0

-4.0

-2.0

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

-1.0

14.0

-2.0

-2.0

-3.0

-3.0

-4.0
ANS

-5.0

Y

Y

-6.0

Predicted Y

Predicted Y

ANS

Graph 19

PREDICTION OF Ia-LS FROMRatio ANS
POINT
Parameters
Change

Regression
Coefficient

0.01

NS

0.36

4.0

Pearson correlation

0.19

3.0

ANS

2.0
1.0

Pro-LS

La-LS

0.0
-4.0

-2.0

0.0
-1.0

2.6:1

2.0

4.0

6.0

ANS

10.0

12.0

14.0

4.3:1(-)

-2.0
-3.0

8.0

Ia-Ls

-4.0


-5.0

Y

-6.0
ANS

Predicted Y

Graph 21

PREDICTION OF A-SLS FROM POINT UI

Graph 20

PREDICTION OF ANS-Sn FROM POINT UI

8.00

12.0

6.00

10.0
8.0

4.00

6.0

A-SLS

ANS-Sn

4.0
2.0
0.0
-2.0

0.0

2.0

4.0

6.0

8.0

10.0

-2.0

-2.00

2.00

0.00
0.00

2.00

4.00

6.00

8.00

10.00

-2.00

-4.0
-6.0

-4.00
-8.0

Y

Y

-10.0

Predicted Y

UI

-6.00

UI

Predicted Y

Graph 21

PREDICTION OF A-SLS FROM POINT UI
Ratio
Parameters
Change

Regression
Coefficient

0.03

NS

0.17

8.00

Pearson correlation

0.23

6.00

A-SLS

4.00

-2.00

2.00

0.00
0.00
-2.00

-4.00

-6.00

UPPER
INCISOR

2.2:1

ANS-Sn
UPPER
INCISOR
2.00

4.00

6.00

8.00

10.00

1.9:1


A-SLS

Y

UI

Predicted Y

Graph 23

Graph 22

PREDICTION OF Ia-LS FROM POINT UI

PREDICTION OF Pro-LS FROM POINT UI
8.00

4.00

7.00

3.00

6.00

2.00

5.00

1.00

La-LS

Pro-LS

4.00
3.00
2.00

-2.00

0.00
0.00
-1.00

2.00

4.00

6.00

8.00

-2.00

1.00
-3.00

-2.00

0.00
0.00
-1.00

2.00

4.00

6.00

8.00

-4.00

10.00

-5.00

-2.00
-6.00

-3.00

UI

Y
UI

Y

Predic

Predicted Y

Graph 23

PREDICTION OF Ia-LS FROM POINT UI
Ratio
Parameters
Change

Pearson correlation

Regression
Coefficient

0.16

0.18

0.15

0.18

4.00
3.00
2.00

La-LS

1.00

-2.00

0.00
0.00
-1.00

UPPER
INCISOR
Pro-LS
2.00

3.5:1
4.00

6.00

8.00

10.00

-2.00
-3.00
-4.00

UPPER
INCISOR

5.7:1 (-)

-5.00
-6.00

Ia-Ls

Y
UI

Predicted Y

PT.A

Y
Predicted Y

LIP LENGTH CHANGE
Graph 24

Graph 25

PREDICTION OF Sn-STO FROM POINT A

PREDICTION OF LIPLT FROM POINT A

3.5

4.0

3.0

3.0

2.5
2.0

2.0
1.0

LIPLT

SN-STO

1.5
1.0
0.5

0.0
-10.0

-8.0

-6.0

-4.0

-2.0

0.0
-10.0

-8.0

-6.0

-4.0

-2.0

0.0

2.0

-1.0

0.0

2.0

4.0

4.0

-0.5

-2.0

-1.0

-3.0

-1.5

PT.A

PT.A

Y
Predicted Y

Y
Predicted Y

Graph 25

PREDICTION OF LIPLT FROM POINT A
Ratio
Parameters
Change

Pearson correlation

Regression
Coefficient

0.21

-0.1

4.0

Point A

3.0

(-)2.9:1
2.0

LIPLT

Sn-STO
-10.0

-8.0

-6.0
-4.0
Point A

LIPLT

1.0
0.0
-2.0

0.0

2.0

4.0

-1.0
(-)4.6:1
0.24
-2.0
-3.0

0.11

Graph 27

Graph 26

PREDICTION OF LIPLT FROM POINT ANS

PREDICTION OF Sn-STO FROM POINT ANS
3.5
3.0

4.0

2.5

3.0

2.0
2.0

Sn-STO

1.5
1.0

1.0

LIPLT

0.5

0.0

0.0
-10.0

-8.0

-6.0

-4.0

-2.0

-0.5

0.0

2.0

4.0

6.0

-8.0

8.0

-6.0

-4.0

-2.0

0.0

2.0

4.0

6.0

8.0

-1.0

-1.0
-2.0

-1.5

ANS

-3.0

ANS

Y

Y

Predicted Y

Predicted Y

Graph 27

PREDICTION OF LIPLT FROM Ratio ANS
POINT
Parameters
Change

Pearson correlation

Regression
Coefficient

-0.14

-0.05

0.19

0.07

4.0

ANS

3.0

(-)2.1:1

2.0

Sn-STO
LIPLT

1.0

-8.0

-6.0

-4.0

ANS

0.0

-2.0

0.0
-1.0

LILPT

2.0

(-)3.3:1
4.0

6.0

8.0

-2.0
-3.0

ANS

Y
Predicted Y

Graph 28

Graph 29

PREDICTION OF Sn-STO FROM POINT UI

PREDICTION OF LIPLT FROM POINT UI
4.00

3.00

3.5
3.0

2.00

2.5
2.0

1.00

LIPLT

Sn-STO

1.5
1.0

-14.00

0.5

-12.00

-10.00

-8.00

-6.00

-4.00

-12.0

-10.0

-8.0

-6.0

-4.0

-2.0

-0.5

0.00
0.00

2.00

0.0

2.0

4.0

-2.00

-1.5

Y
Predicted Y

UI

-3.00

UI

Graph 29

PREDICTION OF LIPLT FROM POINT UI
Ratio
Parameters
Change

Pearson correlation

Regression
Coefficient

0.11

4.00

NS

0.01

NS

3.00

LIPLT
-14.00

-12.00

Sn-STO

-10.00

-8.00

-6.00

2.00

(-)3.5:1
1.00

-4.00

-2.00

0.00
0.00

-2.00

(-)5.6:1
-3.00

LILPT

2.00

4.00

6.00

-1.00

UPPER
INCISOR
UI

6.00

6.0

-1.0

UPPER
INCISOR

4.00

-1.00

0.0
-14.0

-2.00

Y
Predicted Y

Y
Predicted Y

DISCUSSION


• Cephalometric radiographs, photographic
analysis, and mounted casts are routinely
used for diagnosis and treatment planning
of maxillary surgeries. In these, prediction
tracings are mainly based on the
functional and esthetic requirements of
the patient

• The predictability of maxillary surgery is
influenced by the ability of the surgeon
to accurately place the maxilla, the
stability of the maxilla in its new
location, and the variability of the soft
tissue response.


• It was found that most of the hard
tissue points showed a good correlation
with the final outcome, in both the
horizontal and vertical position.
• Jacobson and Sarver, Bryan and
Hunt as well as Mankad et al. also
showed a good correlation with various
predicted and post treatment results.

• In this study it was found out that the lip
thickness decreased at the base of the
nose and at the soft tissue point A,
however at the vermillion border of the
upper lip the thickness actually
increased.


• Lines and Steinhauser reasoned that
the soft tissue in the maxilla was
prevented from following the hard
tissue in a one-to-one manner, as in the
mandible, because of the fact that it
was firmly connected to the base of the
nose.

• In this study the length of the upper lip
was divided into two parts one being
Sn-STO which was seen to be
increasing
with
the
superior
repositioning of the maxilla. The other
being LIPLT which tells us of the
curvature which was seen to be
decreasing showing that the upper lip
became straighter.

Summary and Conclusion


1. The hard tissue prediction done using the method
devised by Fish and Epker was found to be
reliable.
2. The upper lip thickness (ANS-Sn) decreased at
the base of the nose after a Lefort I osteotomy.

3. The vermillion border of upper lip (Pro-Ls, Ia-Ls)
becomes thicker after a lefort I osteotomy.

4.

On doing a lefort I osteotomy the upper lip length
(Sn-STO) increases.

5.

Lefort I osteotomy decreases the mid lip length

(LIPLT) because of straightening of the lip.


THANK YOU


Prediction of maxillary repositioning in lefort 1 surgery /certified fixed orthodontic courses by Indian dental academy

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