This study aimed to identify cephalometric predictors of a successful response to functional appliance therapy in patients with Class II skeletal patterns. The study compared pre-treatment measurements and treatment changes between patients who responded well to therapy versus those who did not. It found that patients with a more favorable response tended to have a lower mandibular plane angle, lower basal plane angle, and higher Jarabak's ratio pre-treatment. Following treatment, successful patients demonstrated an increase in ramus height, decrease in overjet, increase in SNB angle, and increase in Jarabak's ratio. Identifying these predictors could help orthodontists select patients most likely to benefit from functional appliance therapy.

1. 1
GROWTH MODULATION
USING FUNCTIONAL
APPLIANCES -
CEPHALOMETRIC
PREDICTORS OF
SUCCESSFUL RESPONSE
Dr. Sharanya Ajit Kumar, Dr. K. Sadashiva
Shetty, Dr. A.T. Prakash

2. Authors
2
Dr. Sharanya Ajit Kumar Dr. K. Sadashiva Shetty Dr. A.T. Prakash

3. Authors
3
 Dr. Sharanya Ajit Kumar, B.D.S, M.D.S, Senior Lecturer,
Dept of Orthodontics and Dentofacial Orthopedics, ,
Vydehi Institute of Dental Sciences & Research Centre,
#82, E.P.I.P Area, Nallurahalli, Whitefield Bangalore -
560066, Karnataka, India
Email – drsharanyaortho@gmail.com
 Dr. K. Sadashiva Shetty, M.D.S, Professor and Head,
Dept of Orthodontics and Dentofacial Orthopedics, and
Principal, Bapuji Dental College & Hospital, Davangere,
Karnataka, India. Email- bapujidental@gmail.com
 Dr. A.T. Prakash, M.D.S, MOrth RCSEd, Reader, Dept of
Orthodontics and Dentofacial Orthopedics, Bapuji Dental
College & Hospital, Davangere, Karnataka, India, Email-

4. INTRODUCTION
 Control and modification of growth of the
skeletal structures of the craniofacial
complex,
 Prominent but controversial area of interest
and activity within the field of orthodontics
since its inception.
 Growth modulation : functional
appliances -topic of much debate.
 key factors to its success - correct
diagnosis, case selection, appliance
design and patient co-operation.
4

5.  Selecting cases that will ensure a successful response
to functional appliance therapy remains a problem
because the treatment results are often variable and
unpredictable.
 A treatment outcome that has been particularly
questioned is the enhancement of mandibular growth.
 Differing responses
 due to the design of the appliances.
 different functional appliance designs act in dissimilar ways
and are not directly comparable
 Individual differences in sensory and neuromuscular response
5

6. 6
 Assuming that a patient is compliant,
 pre-treatment skeletal morphological factors are
responsible for a favourable or an unfavourable
treatment outcome.
 Categorizing cases according to the orthopedic
response to treatment provides an opportunity for
comparing characteristics and identifying differences
between those that responded with a skeletal change
and those that did not.

7. OBJECTIVES
 To determine whether there are any skeletal
morphologic features evident on a pre-treatment lateral
cephalogram that may be used to predict a successful
improvement in the sagittal dental base relationship
during functional appliance therapy in patients with a
Class II skeletal pattern.
 To compare the treatment changes between cases
which responded favorably to growth modulation using
functional appliances and those which did not.
7

8. METHODOLOGY
 SOURCE OF DATA
 24 patients with class II skeletal pattern treated with
functional appliance therapy were selected for the study,
from the Department of Orthodontics and Dentofacial
Orthopedics, Bapuji Dental College and Hospital,
Davangere.
 Two sets of lateral cephalograms- Pre-treatment and
Post-functional cephalograms were used for the study.
8

9. CRITERIA FOR SELECTION
OF DATA
 Class II skeletal bases
 Growing patients treated
with functional appliance to
advance the mandible –
Twin Block or Frankel
Appliance.
 All patients were compliant.
9

10. METHOD OF COLLECTION OF
DATA10
 Pre-treatment and post-functional lateral cephalograms
were analyzed and the change in the ANB angle was
used to determine the skeletal response to treatment with
functional appliance.
 Based on the change in the ANB angle the patients were
divided into two groups of 12 patients each:
 Group 1- 12 patients who demonstrated a change in
ANB angle of 4° or more were identified as the
Skeletal group.
 Group 2- 12 patients who demonstrated a change in
ANB angle of 1° or less were identified as the Non
Skeletal group.

11. 2 parts of study
11
 Comparisons were made between the mean pre-
treatment (T1) parameters of Group I (Skeletal) and
Group II (Non skeletal) to assess any pre-treatment
parameters which were significantly different between
the groups.
 Changes due to functional appliance therapy from pre-
treatment (T1) to post-functional (T2) stage was
measured as T2-T1 in both Group I (Skeletal) and Group
II (Non skeletal). The mean changes seen in Group I
(Skeletal) and Group II (Non skeletal) were then
compared to assess the difference between changes
brought about by growth modulation using functional

12. STATISTICAL ANALYSIS
12
 Descriptive data that included mean and standard
deviation values were calculated for the linear, angular
and percentage parameters.
 Results were expressed as mean and Standard
deviation. Comparative statistical analysis of the data
between both groups was done using One Way
Analysis Of Variance (ANOVA) – F-TEST.
 A ‘P’ value of < 0.05 was set for statistical significance.

13. LANDMARKS
USED
13
REFERENCE LINES
PLANES

14. LINEAR PARAMETERS
14
1. Sella-Nasion
2. Sella-Articulare
3. Upper anterior
facial height
(UAFH)
4. Lower anterior
facial height (LAFH)
5. Condylion-Gonion
6. Condylion-Gnathion
7. Gonion-Gnathion
8. Overbite
9. Overjet

15. ANGULAR PARAMETERS
15
1. Nasion-Sella-Articulare
2. S-Ar-Go
3. SNA
4. SNB
5. ANB
6. SN-MxP
7. SN-MnP
8. MxP-MnP (Basal Plane
angle)
9. UI to MxP
10. LI to MnP
11. Mandibular arc

16. PERCENTAGE PARAMETER
16
 Jarabak Ratio:
Posterior facial height
(S-Go) multiplied by
100 and divided by
Anterior facial height
(N-Me).

17. RESULTS
17
 Comparisons were made between the mean pre-
treatment (T1) parameters of Group I (Skeletal) and
Group II (Non skeletal) to assess any pre-treatment
parameters which were significantly different between the
groups which may help in predicting the response to
growth modulation.
 Table 1 presents comparative data for the pretreatment
cephalometric measurements at the start of treatment
(T1) for the two groups.

18. 18
Pre-treatment (T1) Cephalometric Variables
Variable
Group 1 Group 2
F value P value Significance
Mean SD Mean SD
S-N (mm) 69.30 3.20 68.60 3.40 0.25 0.65 NS
S-Ar (mm) 34.10 3.10 33.10 2.50 0.76 0.39 NS
UAFH (mm) 48.30 2.30 49.50 3.70 0.88 0.36 NS
LAFH (mm) 51.80 6.30 53.90 3.80 1.04 0.32 NS
Cd-Go (mm) 49.80 4.10 48.80 3.90 0.38 0.54 NS
Cd-Gn (mm) 101.00 3.50 101.40 8.50 0.03 0.88 NS
Go-Gn (mm) 67.40 2.50 68.20 6.20 0.15 0.7 NS
overbite (mm) 3.60 1.70 3.30 2.10 0.19 0.67 NS
overjet (mm) 10.10 1.30 8.30 3.10 3.22 0.09 NS
NSAr (deg) 126.00 4.00 125.30 4.40 0.15 0.7 NS
SArGo (deg) 142.20 7.00 146.60 4.90 3.21 0.09 NS
SNA (deg) 80.30 3.50 79.80 3.00 0.1 0.76 NS
SNB (deg) 73.70 2.90 73.70 3.30 0 1 NS
ANB (deg) 6.60 1.40 6.20 1.30 0.57 0.46 NS
SN-MxP (deg) 8.10 3.90 9.80 2.00 1.94 0.18 NS
SN-MnP (deg) 30.00 3.90 34.40 3.60 8.28 0.05 S
Basal plane angle
(deg)
21.90 4.40 25.30 2.30 5.76 0.05 S
Mand arc (deg) 31.70 3.40 31.10 4.10 0.12 0.74 NS
UI-MxP (deg) 55.80 8.30 60.80 4.20 3.35 0.08 NS
LI-MnP (deg) 104.80 2.90 100.30 7.00 4.07 0.06 NS
Jarabak ratio (%) 67.20 3.70 63.90 3.00 5.75 0.05 S

19. Pre-treatment angular parameters
19

20. Pre-treatment percentage
parameter20

21. 21
 Changes due to functional appliance therapy from pre-
treatment (T1) to post-functional (T2) stage was
measured as T2-T1 in both Group I (Skeletal) and
Group II (Non skeletal).
 The mean changes seen in Group I (Skeletal) and
Group II (Non skeletal) were then compared in Table 2
to assess the difference between changes brought
about by growth modulation using functional appliances
between both groups.

22. 22
Changes in Cephalometric Variables from Pre-Rx to Post-functional
Variable
Group 1 Group 2
F value P value Significance
Mean SD Mean SD
S-N (mm) 1.7 1.7 1.3 1 0.53 0.47 NS
S-Ar (mm) 1.7 1.6 1 1.8 0.97 0.34 NS
UAFH (mm) 1.8 1.5 2 1.5 0.16 0.69 NS
LAFH (mm) 5.1 3.5 4.3 2 0.52 0.48 NS
Cd-Go (mm) 4.5 3.3 1.9 1.8 5.8 <0.05 S
Cd-Gn (mm) 6.4 4.8 4.8 2.6 1.01 0.33 NS
Go-Gn (mm) 3.2 2.4 2.8 2.1 0.13 0.72 NS
overbite (mm) -1.1 2.1 -0.7 2 0.25 0.62 NS
overjet (mm) -6.5 2.8 -3.7 2.5 6.64 <0.05 S
NSAr (deg) -0.9 1.9 -0.2 2 0.88 0.36 NS
SArGo (deg) 1.2 5.6 -1.1 2.4 1.64 0.21 NS
SNA (deg) -0.3 1.8 0.4 1 1.63 0.22 NS
SNB (deg) 3.8 1.9 1 0.9 23.2 <0.001 HS
ANB (deg) -4.2 0.4 -0.6 0.5 369.8 <0.001 HS
SN-MxP (deg) -0.6 2.7 -0.6 2.1 0 1 NS
SN-MdP (deg) -1.2 3.5 0.3 2.3 1.34 0.26 NS
Basal plane angle (deg) -0.6 2.1 0.2 3.3 0.45 0.51 NS
Mand arc (deg) 0.4 3.6 0 4.2 0.07 0.8 NS
UI-MxP (deg) 8.3 7.9 4.9 5.6 1.42 0.25 NS
LI-MnP (deg) 3.8 5.8 0.3 3.4 3.08 0.09 NS
Jarabak ratio (%) 2.6 2.2 0.3 1.5 8.94 <0.01 S

23. Change in linear parameters
23

24. Change in linear parameters
24

25. Change in angular
parameters25

26. Change in percentage
parameter26

27. Discussion
27
 Comparison of ramus height (Cd-Go) between the 2
groups at pre-treatment stage revealed no significant
difference.
 Thus the cases all had a short ramus at the start of treatment.
 But as a result of treatment the Cd-Go in the skeletal
group increased a mean of 4.5 mm but in the non
skeletal the mean increase was only 1.9 mm. -
statistically significant. - successful cases the ramus
growth in the vertical direction contributes to correction.

28. 28
 In the skeletal group the overjet decreased to a
significant extent (6.5mm) compared to the non skeletal
group (3.7mm).
 the decrease in overjet can be attributed partly to the forward
position of the mandible in the skeletal group.
 The mean change in SNB in skeletal group was found to
be 3.8 +/- 1.9 deg and for non skeletal group was found to
be 1 +/- 0.9 deg. -statistically highly significant. For
those who responded skeletally, there is a much greater
forward movement of B point.

29. 29
 The comparison of the SN-MnP values between the
groups at the pre- treatment stage showed that the
mean value of SN-MnP in the skeletal group was 30 deg
and for the non skeletal group was 34.4 deg.
 The difference was statistically significant. This was in
agreement with studies by Pancherz and Franchi L.
and Baccetti. They believed that the prognosis of
treating class II malocclusions is partly dependant on
mandibular plane angle.

30. 30
 The mean pre-treatment value of basal plane angle in
the skeletal group was found to be 21.9 deg and for the
non skeletal group was found to be 25.3 deg.
 The difference was statistically significant. This also
goes to prove that the skeletal group at the pre-
treatment stage had more converging jaw bases which
reflect a more horizontal growth direction.

31. 31
 The mean value of Jarabak’s ratio in the skeletal group
was found to be 67.2 % and for the non skeletal group was
found to be 63.9 %. The difference was statistically
significant showing that at the pre-treatment stage the
skeletal group had an increased PFH to AFH ratio
indicating a more horizontal growth pattern compared to
the non skeletal group.
 The mean value of the change in Jarabak’s ratio in the
skeletal group was found to be 2.6 % and for the non
skeletal group was found to be 0.3 %. The difference was
statistically significant implying that in the skeletal group
a significant increase in the posterior facial height was
achieved compared to in the non-skeletal group.

32. Conclusion
 The pre-treatment
parameters which
related to a favourable
response were
 low mandibular plane
angle,
 low basal plane angle,
 high Jarabak’s ratio
 Also in those cases
which responded
favorably the changes
seen were
 increase in Cd-Go,
 decrease in overjet,
 increase in SNB,
 increase in Jarabak’s
ratio
32
Pre treatment parameters Changes seen

33. Significance
33
 The significance of these results will only have clinical
use if patients with high growth potential can be
identified at the start of treatment.
 Further work on a greater number of patients would be
required to attempt to relate mandibular variables to
such successful outcomes, eventually allowing the
production of an index for mandibular features for
various age groups.
 This would give the most accurate prediction perhaps of
whether or not growth modification with functional
appliances would be possible in any individual case.

34. SCOPE FOR FUTURE STUDY
34
 A prospective study could be planned with sample size
categorized uniformly considering the gender.
 Increasing the sample size could facilitate more
substantial results.
 A three dimensional representation like Computed
Tomography (CT) scan could give better results and less
errors.
 An index could be prepared to be used for case
selection for growth modulation.

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