enlows counterpart principle pg level has articles included

2. JOURNAL OF AMERICAN DENTAL ASSOCIATION,1971

3. Bony growth movements
Direct cortical drift
Combination of
deposition and
resorption
Causes overall
enlargement of bone
and simultaneous
remodeliing
Displacement
Repositions bone as a
unit

4. • The multiple growth processes in all the various parts
of the face and cranium are described separately as
individual "regions" or "stages”.
• The face of each of us is the aggregate sum of all the
many balanced and imbalanced craniofacial parts
combined into a composite whole.
• Balanced growth is the Facial and cranial
enlargement, in which form and proportions remain
constant.
• Imbalance growth is when changes in facial shape
and form occur.

5. • Imbalances are produced by differences in respective
amounts or directions of growth.
• A perfectly balanced mode of growth in all the parts of the face
and cranium never occurs in real life.
• Making everything actually fit requires certain normal
"imbalances.“
• The process of compensation is a feature of the developmental
process in order to offset the effects of disproportions in other
regions

6. • Regional imbalances often tend to compensate for one another
to provide functional equilibrium.
• This is the COUNTERPART PRINCIPLE OF CRANIOFACIAL
GROWTH.
• It states, simply, that the growth of any given facial
or cranial part relates specifically to other
structural and geometric "counterparts" in the face
and cranium.

7. TRIPOD ANALOGY

8. DYNAMICS OF
MORPHOGENESIS AS
VISULAISED IN
HEADFILMS

9. • Two reference lines one
vertical and other
horizontal are used so
that amount and direction
of growth changes can
be visualized
• The molars are in class I
relation

10. STAGE 1
• Bony maxillary arch
lengthens in posterior
direction
• The overall length of
maxillary arch has
increased by the same
amount that the Ptm
moves posteriorly

11. STAGE 2:MAXILLARY DISPLACEMENT
• As the maxillary
tuberosity grows and
lengthens posteriorly, the
whole maxilla is
simultaneously carried
anteriorly
Amount of
forward
displacement
Amount of
posterior
lengthening

12. STAGE 3:MANDIBULAR CORPUS
LENGTHENING
• Mandibular corpus
lengthens to match the
elongation of maxilla
• It does so by remodeling
conversion from ramus
Anterior part of
ramus remodels
posteriorly
Corpus elongates Mandibular arch
lengthens

13. STAGE 4:MANDIBULAR RAMUS
REMODELING
• The condyle and the
posterior part of ramus
remodel posteriorly
• This returns the horizontal
dimension of the ramus to the
same breadth
Posterior ramus
deposition Anterior ramus
resorption

14. STAGE 5:MANDIBULAR DISPLACEMENT
• The whole mandible, now, is
displaced anteriorly by the
same amount that the ramus
has relocated posteriorly .
• This is the primary type of
displacement because it
occurs in conjunction with
the bone's own enlargement.

15. • NOTE:
1. The corpus of the mandible elongates primarily in a posterior
direction, just as the maxilla also lengthens posteriorly
2. The whole ramus has moved posteriorly. However, the only
actual change in horizontal dimension involves the mandibular
corpus, which becomes longer. The horizontal dimension of
the ramus remains constant
3. The anterior displacement of the whole mandible equals the
amount of anterior maxillary displacement assuming
everything is perfectly balanced. the class I position of the
teeth has been returned

16. 4. obliquely upward and backward direction of ramus remodeling
must also lengthen its vertical dimension.This separates the
occlusion because the mandibular arch is displaced inferiorly as
well as anteriorly.
5. In both the maxilla and mandible, the type of displacement is
primary
Increment of
backward growth at
maxillary
tuberosity(stage 1)
Amount of forward
displacement of
maxilla(stage 2)
Amount of corpus
lengthening (stage 3)
Growth of posterior
part of ramus
(stage 4)
Mandibular
displacement
(stage 5)

17. STAGE 6:MIDDLE CRANIAL FOSSA
GROWTH
• Increase in dimension of temporal lobes of the cerebrum
and the middle cranial fossa.
• Resorption on the endocranial side and deposition of bone
on the ectocranial side of the cranial floor.
• The spheno-occipital synchondrosis provides endochondral
bone growth in the midline part of the cranial floor.
• Growth expansion of middle fossa now projects it anteriorly
beyond the vertical reference line

18. STAGE 7:SECONDARY DISPLACEMENT
OF NASOMAXILLARY COMPLEX
• As the middle cranial fossa
expands they cause the
secondary displacement of the
nasomaxillary complex.
• The nasomaxillary complex, is
suspended by sutures from the
anterior cranial fossae and
frontal lobes

19. STAGE 8:SECONDARY DISPLACEMENT
MANDIBLE
• The expansion of the
middle cranial fossa, also
has a displacement effect
on the mandible
• SECONDARY
DISPLACEMENT

20. • The extent of maxillary protrusive displacement far
exceeds the amount of mandibular protrusive
displacement
• Because The spheno-occipital synchondrosis lies
between the condyle and the anterior boundary of the
middle cranial fossa .
• The result is an offset horizontal placement between
the upper and lower arches.
• The upper incisors show an "overjet," and the molars
are in a Class II position

21. STAGE 9:COUNTERPARTS:MCF-RAMUS
• The horizontal growth of the
ramus places the
mandibular arch in a more
forward position.
• What the middle cranial
fossa does for the maxillary
body, in effect, the ramus
does for the mandibular
body.

22. • The horizontal (not oblique) dimension of the ramus
now equals the horizontal (not oblique) dimension of
the middle cranial fossa.

23. • Both ramus and middle cranial fossa are counterparts
of the pharyngeal space.
• The skeletal function of the ramus is to bridge the
pharyngeal space and the span of the middle cranial
fossa in order to place the mandibular arch in proper
anatomic position with the maxilla.
• The anteroposterior breadth of the ramus is critical. if it
is too narrow or too wide the ramus places the lower
arch too retrusively or too protrusively respectively

24. STAGE 10:MAINTAINING VERTICAL
BALANCE
• The entire mandible is
displaced anteriorly at the
same time that it remodels
posteriorly.
• Condyle projects upward and
backward.
• As a result, mandible
displaces in downward as well
as forward direction.

25. • The total extent of this vertical growth must match the
total vertical lengthening of the nasomaxillary complex
and the upward eruption and drift of the mandibular
dentoalveolar arch.
• The protrusion of the maxilla during Stage 7
(i.e.secondary displacement of nasomaxillary
complex)has now been matched by an equivalent
amount of mandibular protrusion.
• The molars have once again been "returned" to
Class I positions, and the upper incisor has no overjet.

26. STAGE 11
• Growth of the floor of the
anterior cranial fossa
and the forehead occurs
• Deposition on the
ectocranial side with
resorption from the
endocranial side.
• The nasal bones are
displaced anteriorly.

27. Enlarging brain displaces bone of
calvaria
Bone enlarges by bone deposition
at sutures
Therefore New bone at contact
edges of frontal, temporal, occipital
and parietal bones are formed
Bone is laid down in ectocranial and
endocranial side therefore bone
thickness and perimeter increases

28. • The upper part of the face, which is the ethmomaxillary (nasal)
region, also undergoes equivalent growth increments.
• This facial area increases horizontally to an extent that matches
the expansion of the anterior cranial fossa above and palate
below it. These areas are all counterparts to one another.
• The growth process involves direct bone deposition on the
forward-facing cortical surfaces of the ethmoid, the frontal
process of the maxilla, and the nasal bones. Most of the internal
bony surfaces of the nasal chambers are resorptive.
• anterior displacement takes place in conjunction with growth at
the various maxillary and ethmoidal sutures.

29. STAGE 12
• The vertical lengthening of the
nasomaxillary complex,occurs
by:
• Resorption on the superior
(nasal) side of the palate.
• Deposition on the inferior (oral)
side.
• Produces a downward remodeling
movement of the whole palate
from 1 to 2 .

30. STAGE 13:VERTICAL DRIFT
• Vertical growth by displacement
is associated with bone
deposition at the many and
various sutures of the maxilla
where it contacts the multiple,
separate bones above and
behind it
• Bone is added at these sutures
by amounts equalling whole
maxillary displacement inferiorly

31. • downward movement of the palate
and maxillary arch occurs by:
• Part 1 to 2 – by remodelling and
each tooth’s own movement due to
remodelling on lining surface in
each socket.
THIS IS VERTICAL DRIFT OF TOOTH
• Part 2 to 3 – by sutural growth and
primary displacement and passive
downward displacement of whole
maxillary dentition.

32. STAGE 14:MANDIBULAR ALVEOLAR
DRIFT
• The mandibular teeth and
alveolar bone drift upward to
attain full occlusion.
• This is produced by a superior
drift of each mandibular tooth,
together with a corresponding
remodeling increase in the
height of the alveolar bone.

33. • the extent of downward drift of the maxillary teeth
exceed the extent of upward drift by the mandibular
teeth.
• Much less growth is thus available to "work with" in
major orthodontic movements of the mandibular teeth ,
as compared with the maxillary teeth.
• However, there is a significant extent of vertical drift by
the mandibular anterior teeth if a curve of Spee exists.

34. STAGE 15:ANTERIOR DENTAL CHANGES
• Remodeling changes occur in
the incisor alveolar region, the
chin, and the corpus of the
mandible along with posterior
region(stage 14).
• The lower incisors undergo a
lingual tipping so that the
uppers overlap the lowers for
proper overbite.

35. STAGE 16:ZYGOMA
• Remodelling of the forward part of
the zygoma and the malar region of
the maxilla occurs in this stage
• Just as the maxilla lengthens
horizontally by posterior remodeling
growth, the malar area also
remodels posteriorly.
• Continued deposition of new bone
on its posterior side and resorption
from its anterior side occurs

36. • The amount of deposition on the posterior side,
however, exceeds resorption on the anterior surface,
so that the whole malar protuberance becomes larger.
• The zygomatic process remodels posteriorly by
anterior resorption and posterior deposition.
• Just as the coronoid process relocates backward by
anterior resorption and posterior deposition to keep
pace with the overall posterior elongation of the whole
bone.

37. STAGE 17
• The malar area is moved anteriorly and
inferiorly by primary displacement as it
enlarges.
• The cheekbone thereby proportionately
matches the maxilla in
(1) the directions and amount
of horizontal and vertical
remodeling relocation
(2) the directions and amount
of primary displacement.

38. • This is a simplified, schematic representation used to describe
various dimensional and alignment combinations involved in
craniofacial construction and growth.

39. MORPHOGENETIC
BASIS FOR
CRANIOFACIAL
VARIATIONS

40. ANATOMICAL EXPRESSIONS OF
BONY DIMENSIONS
• three important, primary factors are involved in
the structural expression of the various
dimensions of any given bone. They are:
• its effective dimension;
• its overall size;
• its alignment

41. 1. The structurally effective dimension of a bone or part of a bone
must be differentiated from its total length.
For example, in relating the bony maxillary arch to its
counterpart, the bony mandibular arch, the protrusion of the
chin is not related to the fit of one arch to the other. The
configuration of the chin can have significance in its own right,
but its role as a part of the composite assembly pattern is
secondary
2. . The overall size of a bone is of course an obvious basic factor in
the expression of that bone’s particular dimensions.

42. 3. The third factor is the alignment of the whole bone or the
structurally effective parts of that bone
for example, an alignment (rotation) of segment Co-SE is
changed

44. CRANIOFACIAL VARIATIONS
1. . If the bony maxilla is horizontally long
relative to the mandibular corpus (or
the corpus is short), a retrognathic
profile pattern results.
• A Class I molar relationship can occur,
however, if no other skeletal or dental
dysplasia exists, since the posterior parts
of the bony maxillary and mandibular
arches are not offset. The ramus and the
cranial floor are balanced

45. 2.If the upper part of the nasomaxillary complex becomes
horizontally long relative to the anterior cranial floor,
• a large frontal sinus, sloping forehead, high nasal bridge may
result. The orbits may also appear recessed.
• The profile can appear somewhat retrognathic because of the
upper maxillary protrusion, although no malocclusion need be
present.

46. 3.If the Co-SE segment is horizontally long relative to its anatomic
equivalent the ramus, the entire maxillary complex is in an offset,
anteriorly (and also superiorly)
• A retrognathic pattern results, and a Class II molar relationship can
occur even though the actual dimension of the maxilla equals that of
the corpus.
• If the bony maxillary arch is also long relative to the corpus,
aggravation of the Class II situation is seen

47. 4.If the posterior part of the nasomaxilla is vertically long the
alignment of the ramus adjusts to its vertical length
• the ramus rotates downward and backward, thereby increasing the
expression of its vertical dimension.
• the horizontal length of the ramus is necessarily decreased
• A retrognathic profile is produced and a class II molar relationship
occurs

48. • the functional occlusal plane has rotated downward.
• Unless the vertical dimension in the anterior part of the maxillary
complex becomes correspondingly lengthened, an anterior open bite
results.
• Or, as the ramus rotates downward at the condylar pivot, the ramus-
to-corpus angle may change during growth so that the corpus rotates
upward at the gonial pivot to sustain occlusal contact.
• The mandibular posterior molars, further, may become intruded and
the anterior teeth extruded at the same time.

49. Conversely, if the posterior maxilla is
vertically short, the ramus rotates
forward and upward.
The occlusal plane can then become
aligned in an upward fashion, and the
vertical dimension of the anterior maxilla
is proportionately short
The expressed horizontal length of the
ramus has increased relative to the
cranial floor
the corpus is thereby placed in an
anterior position
A prognathic pattern and Class III molar
relationship results

50. INTRINSIC
ADAPTATIONS
AND
COMPENSATIONS

51. • If the mandibular corpus is long with respect to the bony maxillary
arch, any of several compensatory adjustments can still produce a
good facial profile
• A horizontally long cranial floor,
• A horizontally short ramus.
• the PM vertical dimension may also be long relative to the cranial
floor-ramus composite dimension

52. • a more anterior and inferior alignment of the posterior
part of the cranial floor.
• It produces an inferior and posterior rotation of the ramus
at the condylar pivot

53. • . To obviate an anterior open bite resulting from downward ramus
rotation, the anterior maxilla height increases proportionately.
• Alignment of the occlusal plane occurs by
• alveolar growth,
• a decrease in the gonial angle,
• an intrusion of the mandibular molars and
• an increase in the depth of the overbite.
• Such a resulting aggregate combination might comprise a corpus
with a Class III actual length, a Class II maxillary and cranial floor
position, a Class II molar relationship, and a Class I profile.

54. • If the horizontal dimension of the bony maxillary arch is long
relative to the corpus,
• an increase in the anterior vertical height of the nasomaxilla
• The gonial angle may be more obtuse

55. • A horizontally long bony maxillary arch may also be compensated for
by
• . vertically short PM dimension that allows an upward and forward
rotation of the ramus at the condylar pivot;
• by a vertically high cranial floor-ramus composite;
• or by a posterior and superior rotational alignment of the posterior
portion of the cranial floor

56. CONCLUSION
• The final result of all the regional changes is a craniofacial
composite that has essentially the same form and pattern
present when the first stage began.
• Only the overall size has been altered.
• All the growth changes among the specific parts and
counterparts have been purposefully balanced to give an
understanding of the term ''balanced growth".

57. • It represents the results of the overall process of facial
enlargement.
• This overlay does not, however, represent the actual
growth processes themselves that is, the changes
produced by remodeling, Relocation and displacement.
• It shows the cumulative summation of all four processes
and demonstrates the locations of all the regional parts,
before and after.

58. 1971, Angle Orthodontics
Aim- To examine the role and the incidence of these
intrinsic compensating factors and to relate them to the
different major categories of craniofacial patterns.

59. • While comparing anatomical part directly with its particular
architectural, developmental counterpart , two factors are
considered:-
1. Alignment (rotational position) of the parts relative to each other.
2. The anatomical effect of the sizes ( vertical and horizontal) of the
parts relative to each other.
• This means that any upwards, downwards rotation will directly effect
the horizontal or vertical position of each part.
• The various cranial and facial regions were to found to contribute in
an aggregate manner to the establishment of a composite basis for
over-all maxillary or mandibular protrusive patterns.

60. • Thus, a number of separate but interrelated, regional, cause-and-
effect factors tend to augment each other in a cumulative, composite
manner.
• The Class I individuals, however, are characterized by an effective
balance between variable numbers of offsetting (compensating)
maxillary and mandibular protrusive effects among the various
regional counterpart relationships.
• Class II and III individuals may also show a degree of such intrinsic
compensation but the severity of their over-all skeletal dysplasia is
determined by the distribution and the extent of cumulative,
protrusive effects in conjunction with the extent of some other effects
that provide a greater or lesser degree of intrinsic offset.

61. • Two basic types of Class I and Class II patterns exist. If A point lies
anterior to B point with respect to the functional occlusal plane, the
craniofacial pattern is designated as a Class I A or a Class II A type.
• If B point lies anterior to A point with respect to the functional
occlusal plane, however, the craniofacial pattern is designated as a
Class I B or a Class II B type.
• Class IA group having a Class II (maxillary protrusion) tendency while
Class IIA tends to have a more severe type of skeletal discrepancy.
• Class IIB have a much lesser incidence of severe skeletal discrepancy
due to greater number of compensating Class III anatomical effects.

62. Synergic and Reciprocal Relationships
• If the effects between any two groups of parts and
counterparts are reciprocal (i.e., one has a maxillary protrusive
effect while the other has a mandibular protrusive effect), the
composite anatomical result is thereby partly or wholly
offsetting and compensatory.
• If the two different part-counterpart groups have a common
protrusive effect, this relationship is synergic and their
respective effects are cumulative within that individual. Such
synergic relationships may be either advantageous or
disadvantageous in a given person.

63. • Regional relationships that produce a cumulative, synergic maxillary
protrusion effect in a Class II individual augment and worsen the over-
all extent of his composite maxillary prognathism.
• While regional relationships having synergic mandibular protrusive
effects in a Class II individual are advantageous because they
contribute a degree of regional compensation within the craniofacial
framework and thereby reduce the aggregate extent of maxillary
protrusion.

66. CORPUS-OCCLUSAL COMPENSATORY RELATIONSHIP
• Three essentially different rotational sites are incorporated within
the mandible as a whole:
1. The ramus, which can rotate upward and forward or downward
and backward
2. The corpus, which can rotate either upward or downward
(opening and closing the ramus-to-corpus angular junction)
3. The dental arch, which can undergo an independent upward or a
downward rotation by an extrusion or intrusion of the anterior or
posterior teeth.

67. • The rotational status of the ramus, using the condyle as a pivot, is
directly dependent in a cause-and-effect relationship with the
long or short nature of the relative PM ( midface) vertical
dimension.
• A “short” midface relative vertical length is associated with a
consequent, more forward and upward ramus alignment. A “long”
midface relative vertical length (and often a forward and
downward rotation of PCF as well) , conversely, is related to a
more backward and downward alignment of the ramus.

68. • Two basic compensatory responses or, frequently, a
combination of both can occur to maintain full length closed
occlusion.
1. The maxillary teeth can extrude and descend for a
progressively increasing vertical distance front the posterior
to the anterior ends of the arch. The posterior-most
maxillary tooth remains in the same vertical position, but
each succeeding tooth moves inferiorly for a greater
distance until full-length occlusal contacts are made.

69. • Second, the mandibular teeth can become extruded to a
progressively increasing extent from the posterior to anterior
ends of the arch until contact is made with each corresponding
maxillary tooth.
• A vertically “long” alveolar region characterizes such
individuals in the anterior portion of the mandibular corpus
due to the upward direction of incisor positioning.

70. • However, a progressive extrusion of the corresponding
anterior mandibular teeth completes closure of the intervening
distance to provide full-length occlusal contact. The result is
a distinctive curved contact line from the posterior molars to
the incisors.
• The middle span of the maxillary teeth descends, as in the first
type of adaptive response described above, but the
progressively increasing extent of extrusion required for each
subsequent tooth in the more anterior part of the maxillary
arch falls short.

71. • However, the maxillary teeth do not fully descend
in a progressively increasing manner from back to
front into occlusal contact, although a partial
descent in a curved line often occurs as noted
above.

72. 2023, Diagnostics

73. AIM
• The aim of this study is to provide a method to perform the
analysis of Enlow’s neutral track in 3D.( As enlow 3d analysis
composed of all horizontal , vertical and neutral
counterpart)

74. MATERIAL AND METHOD
• 18 CBCT images of skeletal class I subjects (12male and 6 female)
were taken.
• For each subject, 2D Enlow’s neutral track analysis was
performed on lateral cephalograms extracted from CBCT images
using the OrisCeph3 software and 3D neutral track analysis was
performed on CBCT images using the Materialise Mimics
Software.

75. • Neutral track analysis allows us to evaluate the
“rotational factor” in the craniofacial development and
growth of the following structures: the middle cranial
floor, mandibular ramus, occlusal plane and
nasomaxillary complex.
• 2D ANALYSIS compares individual track with neutral
track .

76. The angle between MCFn and PMn plane remains same 40.3° as in
individual track

77. 3D ANALYSIS
• The same 3 individual track planes (MCF,PM and MR ) were
identified but with different landmarks than the 2D ones.

78. • So to compare both 2D and 3D analysis we used
following angles:
• MCF-PM and
• MCF-RM

79. RESULT
The gap between the values of each variable was small and no
statistically significant difference was highlighted by the paired
Student’s t-test (p > 0.05), confirming the null hypothesis and
suggesting that the proposed 3D analysis method is reliable for
evaluating certain cephalometric angles.

80. CONCLUSION
 This is the first study to propose a method as to how to
perform the neutral track analysis in 3D and is also the first
study proposing a method to analyze the rotational factor of
the craniofacial structures on CBCT.
 This method can further be used in orthodontic diagnostic
phase and in orthognathic surgery planning.

81. • As the ramus rotates downward and backward, the corpus is
necessarily also carried downward with or without any
increase or opening of the gonial angle. A downward-aligned
corpus is thereby produced, but the direct cause is a rotation
of the ramus at the condyle and not a rotation of the corpus.
• In some individuals, the corpus itself can become rotated
inferiorly, independently of the ramus. The mandibular
occlusion, in either case, is also carried into such a downward-
aligned position by the ramus and/or corpus rotation. If no
corresponding occlusal rotational adjustments occur, it is
apparent that open bite situation is created.

82. THANK YOU