Surgical analysis and prediction

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



In modern orthognathic surgery, the orthodontist
and oral surgeon need to work in complete
symbiosis to...




Incorrect positioning of the incisors in either arch
can have a profound influence on the extent of
the overjet (rev...
Surgical analysis

Hard tissue analysis

Soft tissue analysis
SOFT TISSUE CEPHALOMETRIC
ANALYSIS - Legan, Dallas, Burston...
CEPHALOMETRICS FOR
ORTHOGNATHIC SURGERY
(COGS)
Burstone CJ, James RJ, Legan H,
Murphy GA, Norton LA.

J Oral Surg 1978

ww...
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CRANIAL
BASE –

Baseline for
comparison of most
data in this analysis
is HORIZONTAL
REFERENCE
PLANE.(HP)
Co...
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Should not be considered as absolute value, but a
skeletal baseline to be correlated to other measurements
such a...
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Ar – Ptm determines the
horizontal distance
between the posterior
aspects of mandible &
maxilla.
Greater the dist...
HORIZONTAL SKELETAL
PROFILE


All the measurements are made parallel to
horizontal plane that’s why called so.

www.india...
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Angle of facial
convexity :
formed by line N
– A and A-Pg.
Gives an
indication of
overall facial
convexity, but
not ...

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Positive angle – convex face.
Negative angle – concave face.
Clockwise angle is positive.
Counterclockwise is neg...
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Next a
perpendicular line
from HP is dropped
through nasion
the horizontal
position of point A &
B is measured ...
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It describes the apical base of
maxilla/mandible in relation to N.
Surgeon has a quantitative assessment of
A-P posi...
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N – Pg is measured
in same manner.
Indicates the
prominence of chin.
Any unusual small or
large value must be
com...
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The measurements of horizontal skeletal
profile represent facial convexity,
horizontal relation of apical base A & B...
VERTICAL SKELETAL
MEASUREMENTS.
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A vertical discrepancy may reflect an
anterior, posterior or complex dysplasia of
...
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Anterior
component
subdivided into
a) Middle third
face height (NANS).
b) Lower third
face height (ANSGn).
Measured
...
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Posterior component – a)
Posterior maxillary height
is length of a
perpendicular line from
HP intersecting PNS...
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Vertical skeletal measurements of anterior
& posterior components of face will help in
diagnosis of anterior , posterio...
VERTICAL DENTAL
DYSPLASIA

www.indiandentalacademy.com

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Divided into –
a) Anterior
b)Posterior
Anterior – Anterior
maxillary height is
measured by dropping
a perpen...
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POSTERIOR –
a) From maxillary
1st molar m-b cusp
a perpendicular
line is drawn to NF.
b) Similar line from
mandibular...
MAXILLA AND MANDIBLE
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Effective length
of maxilla is
distance from
PNS-ANS.
This distance
along with
measurements
N- ...
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MANDIBLE –
1) Ar-Go quantitates
the length of
mandibular ramus.
2) Go-Pg gives length
of mandibular body.
3) Ar-Go-G...
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These measurements are helpful in
diagnosis of
variations in ramus ht., that effect open
bite/deep bite pro...
DENTAL MEASUREMENTS

www.indiandentalacademy.com


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Occlusal plane (OP)
is drawn from buccal
groove of both
permanent 1st molars
through a point 1mm
apical of incisa...


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If anterior open bite is present 2 OPs must be
drawn and measured separately. Each OP is
assessed as to its steepnes...
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INCREASED –
Skeletal open bite,
lip incompetence,
increased facial
height, retrognathia
or increased MP
angle.
DECRE...
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Measurement AB –
OP is done by
dropping a
perpendicular line
to OP from points
A & B, then
measuring
distance betwee...
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Angulation of
maxillary incisor to
NF and mandibular
incisor to MP is
measured.
They determine
the procumbency
or re...


A consultation with an orthodontist will be
helpful in trying to establish the most
stable relationship of the angulati...
www.indiandentalacademy.com
QUADRILATERAL ANALYSIS

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



Formulated by Di Paolo in 1962.
It attempts to identify skeletal deviations,
in size and...
QUADRILATERAL ANALYSIS
OF LOWER FACE


Maxillary bony arch length - measured,
horizontally between two points projected
o...


anterior limit projecting a
perpendicular from
Pt A upward to
the palatal plane
(ANS-PNS),
posterior limit projecting a...
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Mandibular bony
arch length horizontally between
two points projected
onto the mandibular
plane (GoGn).
anteri...
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Point J -

deepest point of
the curvature formed at the
junction of the anterior portion
of the ramus and the ...


Anterior lower
facial height
(ALFH) is
measured, as
vertical linear
measurement
from the
projection of
point A onto the...


Posterior lower
facial height
(PLFH) is
measured, from
the projection of
PTM onto the
palatal plane to
the projection o...
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These four
measurements –
maxillary bony
base length,
mandibular bony
base length,
anterior lower facial
he...
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The quadrilateral analysis indicates that in
a balanced facial pattern a 1:1 ratio exists
between the maxillary b...
Dental Analysis




Maxillary incisor
position : determined
by drawing a line
through point A
parallel to the anterior
l...


Mandibular
incisor
position -

drawing the line
through point B
parallel to
anterior lower
facial height
(ALFH).


The...
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Pogonion line drawing a line tangent
to pogonion, parallel
to anterior lower facial
height (ALFH).
The most anter...
Sagittal Ratio
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Important in assessing the relative anteroposterior
position of the maxillary and mandibular bony ...
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The lines used to
measure the bony
base lengths in are
extended posteriorly to
point x, which is the
sagittal ang...
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Any forward or
retroposition of the
bony base will cause
unequal lengths of
the posterior legs
(lines A and C)...
Angle of facial convexity
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Measurement of
the skeletal profile.
This angle is
formed by the
intersection of
anterior ...
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It shows possible areas of skeletal
discrepancies, such as posture of the
lower facial complex, cranial base
deflect...
Facial Types
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Type 1. This face has a normodivergent pattern
showing a favorable vertical growth .
In the majority of...
• In the majority
of Type 1 cases,
the maxillary
and mandibular
basal arch
lengths are
equal and the
average vertical
heig...


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

Other possibilities of Type 1 cases are
(B) maxillary denture base length larger than the
mandibular denture bas...
•Type 2. This face is
hypodivergent,
predominantly horizontal
growth pattern .
•There is a reduction in
lower face height ...
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3 possibilities: (A)
Maxillary and
mandibular denture
base lengths are
comparable in size,
(B) maxillary base
...
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Type 3. This face is
hyperdivergent,
predominantly vertical
growth pattern .
There is an increase
in lower face h...
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
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These cases
usually present
with a deep curve
of Spee and a lack
of posterior
alveolar
development.
CLINICAL
SI...
3 possibilities:
(A) Maxillary and
mandibular denture
base lengths are
comparable in size,
(B) maxillary base
length is la...
Mc Namara Analysis




Presented by Dr. James A Mc. Namara as
an original article in the December 1984
issue of the Amer...
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Basis : The Mc Namara analysis is useful
in diagnosis and treatment planning of
the individual patient when v...


This analysis consists of 5 major
sections:

 Relating

maxilla to cranial base
 Relating maxilla to mandible
 Relat...
I.Relating the maxilla to
cranial base:
soft tissue evaluation:


The nasolabial angle is
formed by the intersection
of a...
Norms
110 ° (Scheidemann et al)
102 ° ± 8 ° (Ann Arbor sample)
 Acute naso Labial
angle=Dentoalveolar Protrusion
/ orient...
B) Cant of upper lip:
The cant of the upper lip
should be evaluated
relative to the vertical
orientation of the face.
The ...
Hard tissue evaluation:
The antero-posterior
position of the
maxilla is
determined by
Constructing the Nasion
perpendicula...
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Data derived from the Bolton standards indicate
that the SNA angle increases minimally with age
(approximately 1° fr...


Thus, the
composite
norm for the
relationship of
point A to the
nasion
perpendicular
is 0 mm in the
mixed-dentition
per...

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Drawbacks:  
1) It is affected by position of
nasion, which is itself affected by
cranial base length.
2) There is...


 II)  Relating the mandible to the maxilla

(midface):

www.indiandentalacademy.com
• Effective midfacial
length determined by
measuring a line
from
condylion to point A.
•An Effective
mandibular length is
...
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A given effective midfacial length
corresponds to an effective mandibular
length within a given range. “these are
no...
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If the effective midfacial length is
subtracted from the mandibular length, the
maxillomandibular differential can b...
B) Vertical
Dimension:
•The clinical
appearance of the
relation between
upper and lower jaws
is affected greatly by
lower ...
E.g.: In Mixed dentition Analysis
Mid face Length= 85mm
Lower Anterior Facial Height= 60-62mm
In Medium sized individuals
...
www.indiandentalacademy.com


Significance:

Increase in Lower anterior Facial Height -Mandible appears retrognathic
Decrease in Lower anterior Fac...
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In growing persons, an increased LAFH
camouflages a similar increase in
mandibular length, resulting in the
app...
•Mandibular Plane
Angle: Angle between
F-H plane and GoMe
•Normal Value:22°+/- 4°
• Adult south indian-18.9
•Adult north i...
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Facial axis Angle:
Angle between
a)Posterosuperior
aspect of
pterygomaxillary
fissure to gnathion
b)Line joini...
Excessive vertical development , =Less than
90°(negative value)
 Deficient vertical development, =Higher than
90°(positi...
    

III. Relating the mandible to the
cranial base :

www.indiandentalacademy.com
•The relationship of the
mandible to the cranial base is
determined by measuring the
distance of the pogonion to the
Nasio...
Dentition Analysis:
A.Relating Upper
Incisor To maxilla

A vertical line is
drawn through point A
parallel to nasion ⊥
The...
VERTICAL POSITION Upper Incisor
Clinically, and typically, the incisal edge of
upper incisor lies 2-3 mm below upper lip a...
•B. Relating the lower
incisor to the mandible:
•Anteroposterior position of
Lower Incisor:
•Determined by using a
traditi...
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INDIAN NORMS ( Elbe Peter,
Valiathan Ashima et al JPFA 2000)
ADULT SOUTH INDIAN-2.87mm
ADULT NORTH INDIAN -2.85mm
...
•Vertical position of Lower Incisor
•Evaluated on basis of existing lower anterior
facial height.
• First, the lower incis...
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V. Airway analysis:
Two measurements are used to
examine airway impairment.

www.indiandentalacademy.com





Upper pharynx:

The upper pharyngeal
width is measured from a
point on the posterior
outline of the soft palate to...
Apparent airway
obstruction, as
indicated by an
opening of 2mm or
less in the upper
pharyngeal
measurement is
only an ind...
• Lower

pharynx:

• Lower pharyngeal width
is measured from the
intersection of the
posterior border of the
tongue and in...
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Smaller than average values are not
significant,
Greater than average value,15mm suggests
anterior positioning of th...
Certain conditions associated with greater than
average Lower pharyngeal width are:


Mandibular prognathism



Dento-al...
www.indiandentalacademy.com
Bhat M, Sudha P, Tandon S.(June 2001)
•Used Computerized cephalometrics, in measuring skeletal and
dental relationship in ...
www.indiandentalacademy.com
The following conclusions were
drawn
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Advanced maxillary growth in Bunt boys and
girls
Longer mid facial leng...
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The present study indicate that different
racial or ethnic groups tend to have a
different craniofacial features est...
REFERENCES:_
1.

2.

3.
4.

Burstone CJ, James RB, Legan H:
Cephalometrics for orthognathic surgery.J Oral
Surg 1979 (36);...
5.

6.

Albert Chinappi, Di Paolo RJ: A
quadrilateral analysis of lower face
skeletal patterns. AJO 1970 (58),4;341350.
Di...
7.

8.

Mc Namara JA Jr. A method of
cephalometric evaluation. Am J Orthod.
1984; 86: 449-469
Peter Elbe, Ashima Valiathan...
9.

10.

Thomas G M, Valiathan A: A Cephalometric
comparison of South Indian and North Indian
population using six analysi...
Thank you
For more details please visit
www.indiandentalacademy.com

www.indiandentalacademy.com
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Surgical analysis in orthodontics /certified fixed orthodontic courses by Indian dental academy

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Surgical analysis in orthodontics /certified fixed orthodontic courses by Indian dental academy

  1. 1. Surgical analysis and prediction INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. Introduction   In modern orthognathic surgery, the orthodontist and oral surgeon need to work in complete symbiosis to achieve the final objective of a facial balance in harmony with the underlying dental and skeletal structures. The orthodontist is in a unique position to govern the success of an orthognathic case by precisely positioning the teeth (decompensation) prior to surgery. www.indiandentalacademy.com
  3. 3.   Incorrect positioning of the incisors in either arch can have a profound influence on the extent of the overjet (reverse or positive), and thus on the ability of the surgeon to produce the desired profile changes. It is, therefore, the responsibility of the orthodontist to set clear goals before the start of treatment and to communicate these to the surgical colleague www.indiandentalacademy.com
  4. 4. Surgical analysis Hard tissue analysis Soft tissue analysis SOFT TISSUE CEPHALOMETRIC ANALYSIS - Legan, Dallas, Burstone et al CEPHALOMETRICS FOR ORTHOGNATHIC SURGERY QUADRILATERAL ANALYSIS MC NAMARA ANALYSIS prediction TOMAC: AN ORTHOGNATHIC TREATMENT PLANNING SYSTEM SOFT-TISSUE ANALYSIS- TONY G. McCOLLUM, SOFT TISSUE CEPHALOMETRIC ANALYSIS- Arnett et al VIDEO IMAGING www.indiandentalacademy.com
  5. 5. CEPHALOMETRICS FOR ORTHOGNATHIC SURGERY (COGS) Burstone CJ, James RJ, Legan H, Murphy GA, Norton LA. J Oral Surg 1978 www.indiandentalacademy.com
  6. 6.      CRANIAL BASE – Baseline for comparison of most data in this analysis is HORIZONTAL REFERENCE PLANE.(HP) Constructed plane , 7˚from SN line. Most measurements are made either parallel or perpendicular to horizontal plane. Length of cranial base – Parallel to HP from Ar – N. HP www.indiandentalacademy.com
  7. 7.    Should not be considered as absolute value, but a skeletal baseline to be correlated to other measurements such as maxillary and mandibular length to obtain a diagnosis of proportional dysplasia Patient with cephalometrically large maxilla & mandible may have a normal appearance because of large cranial base. Ar – N is a relatively stable anatomical plane; however it can be changed by cranial surgery that affects N, such as Lefort II & III osteotomies. Or with auto correctional rotations of the mandible where Ar moves closer to N. www.indiandentalacademy.com
  8. 8.    Ar – Ptm determines the horizontal distance between the posterior aspects of mandible & maxilla. Greater the distance between Ar- Ptm, more the mandible will lie posterior to maxilla, assuming all other facial dimensions are normal. One casual factor for prognathism or retrognathism can be evaluated by this measurement www.indiandentalacademy.com
  9. 9. HORIZONTAL SKELETAL PROFILE  All the measurements are made parallel to horizontal plane that’s why called so. www.indiandentalacademy.com
  10. 10.   Angle of facial convexity : formed by line N – A and A-Pg. Gives an indication of overall facial convexity, but not a specific diagnosis of which is at fault – maxilla or mandible. www.indiandentalacademy.com
  11. 11.     Positive angle – convex face. Negative angle – concave face. Clockwise angle is positive. Counterclockwise is negative. www.indiandentalacademy.com
  12. 12.     Next a perpendicular line from HP is dropped through nasion the horizontal position of point A & B is measured to this line + :anterior to line. ̶ : posterior to line www.indiandentalacademy.com N
  13. 13.   It describes the apical base of maxilla/mandible in relation to N. Surgeon has a quantitative assessment of A-P position of jaws and degree of horizontal dysplasia and is important in planning of treatment of anterior jaw horizontal advancement / reduction or total advancement / reduction. www.indiandentalacademy.com
  14. 14.    N – Pg is measured in same manner. Indicates the prominence of chin. Any unusual small or large value must be compared with N – B & B – Pg., to determine if discrepancy is in alveolar process, the chin or mandible proper. Helps to determine if there is a horizontal genial hyperplasia / hypoplasia. B Pg www.indiandentalacademy.com
  15. 15.   The measurements of horizontal skeletal profile represent facial convexity, horizontal relation of apical base A & B points, and chin as related to N. After all the measurements are considered the surgeon has a quantitative skeletal cephalometric facial description of horizontal anterior facial discrepancy. www.indiandentalacademy.com
  16. 16. VERTICAL SKELETAL MEASUREMENTS.    A vertical discrepancy may reflect an anterior, posterior or complex dysplasia of the face. therefore these measurements are divided into – Anterior & Posterior components. www.indiandentalacademy.com
  17. 17.   Anterior component subdivided into a) Middle third face height (NANS). b) Lower third face height (ANSGn). Measured perpendicular to HP. HP N AN S Gn www.indiandentalacademy.com
  18. 18.     Posterior component – a) Posterior maxillary height is length of a perpendicular line from HP intersecting PNS. b) Divergence of mandible posteriorly is shown by MP-HP angle.MP is formed by Go-Gn. It relates to posterior facial divergence with respect to anterior facial height. Both these measurements define the vertical dysplasia of the posterior components. HP www.indiandentalacademy.com
  19. 19.  Vertical skeletal measurements of anterior & posterior components of face will help in diagnosis of anterior , posterior , or total vertical maxillary hyperplasia or hypoplasia, and clockwise or counterclockwise rotations of the maxilla & mandible. www.indiandentalacademy.com
  20. 20. VERTICAL DENTAL DYSPLASIA www.indiandentalacademy.com
  21. 21.      Divided into – a) Anterior b)Posterior Anterior – Anterior maxillary height is measured by dropping a perpendicular from incisal edge to nasal floor (NF). Anterior mandibular height – incisal edge to mand plane ( MP). These 2 measurements determine how far incisors have erupted in relation to NF and MP. NF MP www.indiandentalacademy.com
  22. 22.   POSTERIOR – a) From maxillary 1st molar m-b cusp a perpendicular line is drawn to NF. b) Similar line from mandibular m-b cusp to MP. All these values should be related to ANS-Gn & MPHP to establish whether the origin of maxillary & mandibular discrepancies is skeletal, dental or both. www.indiandentalacademy.com
  23. 23. MAXILLA AND MANDIBLE   Effective length of maxilla is distance from PNS-ANS. This distance along with measurements N- ANS, N – PNS gives a quantitative description of maxilla in skull complex. www.indiandentalacademy.com
  24. 24.   MANDIBLE – 1) Ar-Go quantitates the length of mandibular ramus. 2) Go-Pg gives length of mandibular body. 3) Ar-Go-Gn angle gives relation between ramal plane & mandibular plane. 4) B-Pg describes the prominence of chin related to mandibular denture base. www.indiandentalacademy.com
  25. 25.      These measurements are helpful in diagnosis of variations in ramus ht., that effect open bite/deep bite problems, increased /diminished mandibular body length, acute or obtuse Go angle that also contribute to skeletal open/closed bite. Assessment of chin prominence. www.indiandentalacademy.com
  26. 26. DENTAL MEASUREMENTS www.indiandentalacademy.com
  27. 27.    Occlusal plane (OP) is drawn from buccal groove of both permanent 1st molars through a point 1mm apical of incisal edge of central incisors in respective arch. OP angle is angle between OP and HP. If the teeth overlap anteriorly to produce an overbite the OP can be drawn as a single line HP www.indiandentalacademy.com
  28. 28.   If anterior open bite is present 2 OPs must be drawn and measured separately. Each OP is assessed as to its steepness or flatness in relation to HP. Vertical facial & dental heights should be considered to determine which OP should be corrected. www.indiandentalacademy.com
  29. 29.   INCREASED – Skeletal open bite, lip incompetence, increased facial height, retrognathia or increased MP angle. DECREASED – Deep bite, decreased facial height, lip redundancy. www.indiandentalacademy.com
  30. 30.   Measurement AB – OP is done by dropping a perpendicular line to OP from points A & B, then measuring distance between two intersections. It gives relation of maxillary & mandibular apical base to OP. www.indiandentalacademy.com
  31. 31.   Angulation of maxillary incisor to NF and mandibular incisor to MP is measured. They determine the procumbency or recumbency of incisor & are vital in assessing the long term stability of the dentition. NF MP www.indiandentalacademy.com
  32. 32.  A consultation with an orthodontist will be helpful in trying to establish the most stable relationship of the angulation of the teeth to the denture base and to the lips and tongue. www.indiandentalacademy.com
  33. 33. www.indiandentalacademy.com
  34. 34. QUADRILATERAL ANALYSIS     Formulated by Di Paolo in 1962. It attempts to identify skeletal deviations, in size and position, in both the horizontal and the vertical dimensions, regardless of dentoalveolar relationships. It provides an individualized skeletal assessment of each patient. Proportional analysis which is based on theorems in Euclidean geometry. Sample – 245 subjects, mean age-12.6 yrs. www.indiandentalacademy.com
  35. 35. QUADRILATERAL ANALYSIS OF LOWER FACE  Maxillary bony arch length - measured, horizontally between two points projected onto the palatal plane. www.indiandentalacademy.com
  36. 36.  anterior limit projecting a perpendicular from Pt A upward to the palatal plane (ANS-PNS), posterior limit projecting a perpendicular from the most inferior portion of the PTM downward to the palatal plane. www.indiandentalacademy.com
  37. 37.     Mandibular bony arch length horizontally between two points projected onto the mandibular plane (GoGn). anterior limit determined by projecting a perpendicular from Pt B downward to the mandibular plane (Go Gn), posterior limit determined by projecting a perpendicular from point J downward to the mandibular plane www.indiandentalacademy.com
  38. 38.     Point J - deepest point of the curvature formed at the junction of the anterior portion of the ramus and the corpus of the mandible. A line is drawn from articulare tangent to the most posterior point on the ramus. A parallel line is then drawn through the innermost point on the curvature of the anterior aspect of the ramus. At a point where the remaining alveolar crest contacts the last molar, a line is drawn parallel to the gonion-gnathion plane. The angle formed is then bisected, and point J is located where this line crosses the inner curvature of the mandible. www.indiandentalacademy.com
  39. 39.  Anterior lower facial height (ALFH) is measured, as vertical linear measurement from the projection of point A onto the palatal plane to the projection of point B onto the gonion-gnathion plane www.indiandentalacademy.com
  40. 40.  Posterior lower facial height (PLFH) is measured, from the projection of PTM onto the palatal plane to the projection of point J onto the gonion-gnathion plane www.indiandentalacademy.com
  41. 41.      These four measurements – maxillary bony base length, mandibular bony base length, anterior lower facial height, and posterior lower facial height form the basis for the quadrilateral analysis of the lower face. www.indiandentalacademy.com
  42. 42.    The quadrilateral analysis indicates that in a balanced facial pattern a 1:1 ratio exists between the maxillary bony base length (Max.Lth.) and the mandibular bony base length (Mand.Lth.); Average of the anterior lower facial height (ALFH) and posterior lower facial height (PLFH) equals these bony base lengths. Max.Lth. = Man Lth = ALFH + PLFH 2 www.indiandentalacademy.com
  43. 43. Dental Analysis   Maxillary incisor position : determined by drawing a line through point A parallel to the anterior lower facial height (ALFH). A perpendicular from this line to the most anterior point on the maxillary incisor should result in a measurement of 5 mm ± 1 mm. www.indiandentalacademy.com
  44. 44.  Mandibular incisor position - drawing the line through point B parallel to anterior lower facial height (ALFH).  The perpendicular distance to the most anterior point of the lower incisor is 2 mm ± 1 mm. www.indiandentalacademy.com
  45. 45.    Pogonion line drawing a line tangent to pogonion, parallel to anterior lower facial height (ALFH). The most anterior point of the mandibular incisor should be ± 2 mm to this line. This measurement will indicate if the chin is excessive or deficient in size www.indiandentalacademy.com
  46. 46. Sagittal Ratio    Important in assessing the relative anteroposterior position of the maxillary and mandibular bony bases. Skeletal malformations of the jaws may be either in the bony bases or located posteriorly. Therefore, pinpointing the area of the deformity will have a significant impact on whether or not certain surgical procedures are indicated. For example, if we are to perform a surgical correction of a mandibular prognathism, it would be necessary to determine whether we should reduce the bony base lengths (body ostectomy or sagittal split setback) or whether we should perform mandibular surgery posterior to the bony base area (vertical osteotomy, etc.). www.indiandentalacademy.com
  47. 47.    The lines used to measure the bony base lengths in are extended posteriorly to point x, which is the sagittal angle When the anterior and posterior lower face heights are parallel and the maxillary and mandibular bony bases are equal, a proportional relation exists with sides A, B, C, and D of the similar isosceles triangles. The ratio of A to B and C to D is called the sagittal www.indiandentalacademy.com
  48. 48.     Any forward or retroposition of the bony base will cause unequal lengths of the posterior legs (lines A and C). In balanced skeletal patterns the sagittal ratio in adolescents is 1.0:1.50 ± 0.05; in adults it is 1.0:1.45 ± 0.05 sagittal angle is 23° ± 1°. www.indiandentalacademy.com
  49. 49. Angle of facial convexity   Measurement of the skeletal profile. This angle is formed by the intersection of anterior lower facial height with anterior upper facial height and relates the quadrilateral to the upper face.(165 178˚)  . www.indiandentalacademy.com
  50. 50.   It shows possible areas of skeletal discrepancies, such as posture of the lower facial complex, cranial base deflections, and bony base discrepancies. The degree of facial convexity will vary, depending upon the skeletal type and the position of the quadrilateral pattern as it relates to the upper face www.indiandentalacademy.com
  51. 51. Facial Types   Type 1. This face has a normodivergent pattern showing a favorable vertical growth . In the majority of Type 1 cases, the maxillary and mandibular basal arch lengths are equal and the average vertical height is equal to the arch length. This balance indicates a harmonious skeletal development of the lower face. www.indiandentalacademy.com
  52. 52. • In the majority of Type 1 cases, the maxillary and mandibular basal arch lengths are equal and the average vertical height is equal to the arch length. •This balance indicates a harmonious skeletal development of the lower face. www.indiandentalacademy.com
  53. 53.     Other possibilities of Type 1 cases are (B) maxillary denture base length larger than the mandibular denture base length and (C) mandibular denture base length larger than the maxillary denture base length Malocclusions in this group are dentoalveolar in origin. Tooth size— arch length discrepancies or anterior or posterior position of the teeth on their respective denture bases account for the majority of problems www.indiandentalacademy.com
  54. 54. •Type 2. This face is hypodivergent, predominantly horizontal growth pattern . •There is a reduction in lower face height with an undesirable growth pattern, resulting in a skeletal deep-bite •In these patients the average vertical height is deficient when compared to the denture base lengths. www.indiandentalacademy.com
  55. 55.     3 possibilities: (A) Maxillary and mandibular denture base lengths are comparable in size, (B) maxillary base length is larger than the mandibular base length, and (C) mandibular base length is larger than the maxillary base length. The significance is that anteroposterior skeletal malrelationships can exist in skeletal deepbite patterns. Type 2 A www.indiandentalacademy.com
  56. 56.    Type 3. This face is hyperdivergent, predominantly vertical growth pattern . There is an increase in lower face height with an undesirable growth pattern, resulting in a skeletal open-bite. In these patients the average vertical height is excessive when compared to the denture base lengths. www.indiandentalacademy.com
  57. 57.     These cases usually present with a deep curve of Spee and a lack of posterior alveolar development. CLINICAL SIGNIFICANCE Posterior alveolar compensation may prevent a dental open-bite in some cases . Leveling mechanics in these patients will cause the underlying skeletal open-bite to be manifested dentally. www.indiandentalacademy.com
  58. 58. 3 possibilities: (A) Maxillary and mandibular denture base lengths are comparable in size, (B) maxillary base length is larger than the mandibular base length, and (C) mandibular base length is larger than the maxillary base length. TYPE 3 A www.indiandentalacademy.com
  59. 59. Mc Namara Analysis   Presented by Dr. James A Mc. Namara as an original article in the December 1984 issue of the American Journal of orthodontics. This method of analysis is derived in part from the principles of the Ricketts’ and Harvold analyses. www.indiandentalacademy.com
  60. 60.      Basis : The Mc Namara analysis is useful in diagnosis and treatment planning of the individual patient when values derived from the tracing of the patients’ head film are compared to established norms; the norms from 3 groups have been derived: The Bolton study The Ann Arbor sample (200 adults) The Burlington sample Composite norms. www.indiandentalacademy.com
  61. 61.  This analysis consists of 5 major sections:  Relating maxilla to cranial base  Relating maxilla to mandible  Relating mandible to cranial base  The dentition  Airway analysis www.indiandentalacademy.com
  62. 62. I.Relating the maxilla to cranial base: soft tissue evaluation:  The nasolabial angle is formed by the intersection of a line tangent to the base of the nose with a line tangent to the upper lip. www.indiandentalacademy.com
  63. 63. Norms 110 ° (Scheidemann et al) 102 ° ± 8 ° (Ann Arbor sample)  Acute naso Labial angle=Dentoalveolar Protrusion / orientation of the base of the nose. www.indiandentalacademy.com
  64. 64. B) Cant of upper lip: The cant of the upper lip should be evaluated relative to the vertical orientation of the face. The upper lip to nasion perpendicular angle should be: 14°± 8° in females (Ann Arbor sample) 8°± 8° in males (adult) www.indiandentalacademy.com
  65. 65. Hard tissue evaluation: The antero-posterior position of the maxilla is determined by Constructing the Nasion perpendicular. The Linear distance from point A to Nasion Perpendicular is Measured Ann Arbor Norm=0.4mm(male) Comp Norm=0mm(Mixed D) . 1mm(adult) www.indiandentalacademy.com
  66. 66.   Data derived from the Bolton standards indicate that the SNA angle increases minimally with age (approximately 1° from ages 6 to 18). Since a 1° change at point A is equivalent to a 1 mm linear change in the position of point A relative to nasion, one can extrapolate the position of point A relative to the nasion perpendicular during the mixed dentition www.indiandentalacademy.com
  67. 67.  Thus, the composite norm for the relationship of point A to the nasion perpendicular is 0 mm in the mixed-dentition person and 1 mm in the adult female and the adult male . www.indiandentalacademy.com
  68. 68.    Drawbacks:   1) It is affected by position of nasion, which is itself affected by cranial base length. 2) There is displacement of point A labially when the roots are anteriorly tipped. www.indiandentalacademy.com
  69. 69.   II)  Relating the mandible to the maxilla (midface): www.indiandentalacademy.com
  70. 70. • Effective midfacial length determined by measuring a line from condylion to point A. •An Effective mandibular length is derived by constructing a line from condylion to anatomic gnathion. www.indiandentalacademy.com
  71. 71.   A given effective midfacial length corresponds to an effective mandibular length within a given range. “these are not directly related to patient’s age or sex” A geometric relationship exists between the effective length of the midface and that of the mandible. Any given effective midfacial length corresponds to a given effective mandibular length. www.indiandentalacademy.com
  72. 72.   If the effective midfacial length is subtracted from the mandibular length, the maxillomandibular differential can be determined. Ideally this differential is 20 mm for small sized persons, 25 -27mm for medium sized persons and 30-33 mm for large sized persons. www.indiandentalacademy.com
  73. 73. B) Vertical Dimension: •The clinical appearance of the relation between upper and lower jaws is affected greatly by lower anterior facial height (measured from ANS to mention). •This linear measurement increases with age and is correlated to the effective length of www.indiandentalacademy.com the midface .
  74. 74. E.g.: In Mixed dentition Analysis Mid face Length= 85mm Lower Anterior Facial Height= 60-62mm In Medium sized individuals Mid face Length= 94 Lower Anterior Facial Height= 65-67mm In Large sized individuals Mid face Length= 100 Lower Anterior Facial Height= 70-73mm www.indiandentalacademy.com
  75. 75. www.indiandentalacademy.com
  76. 76.  Significance: Increase in Lower anterior Facial Height -Mandible appears retrognathic Decrease in Lower anterior Facial Height --Mandible appears prognathic www.indiandentalacademy.com
  77. 77.     In growing persons, an increased LAFH camouflages a similar increase in mandibular length, resulting in the appearance that the chin is in the same position A-P, with respect to cranial base structures. This analysis also includes two other measurements: ·   1) Mandibular plane angle: 2) Facial axis angle of Ricketts: www.indiandentalacademy.com
  78. 78. •Mandibular Plane Angle: Angle between F-H plane and GoMe •Normal Value:22°+/- 4° • Adult south indian-18.9 •Adult north indian-19 ( Elbe Peter, Valiathan Ashima et al JPFA 2000) •Higher Value: Excessive Lower Facial height •Lower Value: Deficiency in Lower Facial Height www.indiandentalacademy.com
  79. 79.     Facial axis Angle: Angle between a)Posterosuperior aspect of pterygomaxillary fissure to gnathion b)Line joining Basion to Nasion Balanced Face =90° www.indiandentalacademy.com
  80. 80. Excessive vertical development , =Less than 90°(negative value)  Deficient vertical development, =Higher than 90°(positive value) Thomas and Valiathan (June 1993) reported normal directed growth of chin 90.65+/- 3.33 89.64 +/- 5.06 (Adult South Indians ) 90.07 +/- 3.16 (Adult North Indians) www.indiandentalacademy.com
  81. 81.      III. Relating the mandible to the cranial base : www.indiandentalacademy.com
  82. 82. •The relationship of the mandible to the cranial base is determined by measuring the distance of the pogonion to the Nasion perpendicular. •According to the composite norms: •In a mixed dentition (balanced face) pog lies 8mm to 6mm (i.e., posterior) with respect to Nasion • In adult male the chin position is usually -2mm to +2,, relative to Nasion perpendicular. www.indiandentalacademy.com
  83. 83. Dentition Analysis: A.Relating Upper Incisor To maxilla A vertical line is drawn through point A parallel to nasion ⊥ The distance from point A to the facial surface of Upper incisor is measured  A-P position of Upper incisor Comp Norms= 6mm(Adults) 4www.indiandentalacademy.com
  84. 84. VERTICAL POSITION Upper Incisor Clinically, and typically, the incisal edge of upper incisor lies 2-3 mm below upper lip at rest. This is subject to adjustment depending on functional state of lip musculature and axial inclination of the tooth prior to treatment. www.indiandentalacademy.com
  85. 85. •B. Relating the lower incisor to the mandible: •Anteroposterior position of Lower Incisor: •Determined by using a traditional version of the Ricketts measurement of the facial surface of the lower incisor to the A-Pog line. •Bolton study Norms: 1.5 mm anterior to the A Pog. Line. •Ann Arbor Norms :2.32.7mm anterior to the A Pog. Line. www.indiandentalacademy.com
  86. 86.    INDIAN NORMS ( Elbe Peter, Valiathan Ashima et al JPFA 2000) ADULT SOUTH INDIAN-2.87mm ADULT NORTH INDIAN -2.85mm www.indiandentalacademy.com
  87. 87. •Vertical position of Lower Incisor •Evaluated on basis of existing lower anterior facial height. • First, the lower incisor tip is related to the functional occlusal plane. •If curve of Spee is excessive: •a) lower incisor is to be intruded (if LAFH is normal/excess) OR • b)lower molar is allowed to erupt and lower incisor extruded. (when LAFH is inadequate). www.indiandentalacademy.com
  88. 88.   V. Airway analysis: Two measurements are used to examine airway impairment. www.indiandentalacademy.com
  89. 89.    Upper pharynx: The upper pharyngeal width is measured from a point on the posterior outline of the soft palate to the closest point on the posterior pharyngeal wall. This is because the area immediately adjacent to the posterior opening of the nose is critical in determining upper respiratory patency. www.indiandentalacademy.com
  90. 90. Apparent airway obstruction, as indicated by an opening of 2mm or less in the upper pharyngeal measurement is only an indicator of possible airway impairment.  For a more accurate diagnosis, an ENT examination is required. www.indiandentalacademy.com
  91. 91. • Lower pharynx: • Lower pharyngeal width is measured from the intersection of the posterior border of the tongue and inferior border of the mandible to the closest point on the posterior pharyngeal wall. •Ann Arbor sample =1012mm ( average value) does not change appreciably with age. www.indiandentalacademy.com
  92. 92.   Smaller than average values are not significant, Greater than average value,15mm suggests anterior positioning of the tongue, either as a result of habitual posture, or due to enlargement of tonsils. www.indiandentalacademy.com
  93. 93. Certain conditions associated with greater than average Lower pharyngeal width are:  Mandibular prognathism  Dento-alveolar anterior crossbite  Bialveolar protrusion of teeth www.indiandentalacademy.com
  94. 94. www.indiandentalacademy.com
  95. 95. Bhat M, Sudha P, Tandon S.(June 2001) •Used Computerized cephalometrics, in measuring skeletal and dental relationship in order to establish norms for Bunt and Brahmin children of Dakshina Kannada using McNamara's analysis. •The experimental group consisted of 40 children 20 Brahmins and 20 Bunts with equal distribution of sex for both the groups. •Age-10-14 years www.indiandentalacademy.com
  96. 96. www.indiandentalacademy.com
  97. 97. The following conclusions were drawn      Advanced maxillary growth in Bunt boys and girls Longer mid facial length in Bunt boys than Brahmin but overall shows bunts to have longer mid facial length. Proclination of upper incisors in Bunt girls than Brahmin girls Prominent chin in Brahmin girls than in Bunt girls Longer mandible in Bunt boys than in girls. www.indiandentalacademy.com
  98. 98.   The present study indicate that different racial or ethnic groups tend to have a different craniofacial features establishing their own norms for the individuals. Therefore the knowledge of the racial and ethnic origin is essential requisite for an accurate evaluation of orthodontic problem and skeletal discrepancies for success of treatment modalities. www.indiandentalacademy.com
  99. 99. REFERENCES:_ 1. 2. 3. 4. Burstone CJ, James RB, Legan H: Cephalometrics for orthognathic surgery.J Oral Surg 1979 (36);269-77. Legan H, Burstone CJ: Soft tissue cephalometric analysis for orthognathic surgery.J Oral Surg 1980 (38);744-751. Burstone CJ: Integumental Profile. AJO 1958 (44); 1-25. Di Paolo RJ, Philip C, Maganzini A: The quadrilateral analysis: An individualized skeletal assessment. AJO 1983 (83),1;19-32. www.indiandentalacademy.com
  100. 100. 5. 6. Albert Chinappi, Di Paolo RJ: A quadrilateral analysis of lower face skeletal patterns. AJO 1970 (58),4;341350. Di Paolo RJ, Philip C, Maganzini A: The quadrilateral analysis: A differential diagnosis for surgical orthodontics. AJO 1984 (86) 6;470-482. www.indiandentalacademy.com
  101. 101. 7. 8. Mc Namara JA Jr. A method of cephalometric evaluation. Am J Orthod. 1984; 86: 449-469 Peter Elbe, Ashima Valiathan, Suresh M. Cephalometric comparison of South Indians and North Indians using Ricketts lateral cephalometric analysis. Journal of Pierre Fauchard Academy 2000; 14(3):113-118. www.indiandentalacademy.com
  102. 102. 9. 10. Thomas G M, Valiathan A: A Cephalometric comparison of South Indian and North Indian population using six analysis. Dissertation submitted to Mangalore university, June 1993 .Bhat M, Sudha P, Tandon S: Cephalometric norms for Bunt and Brahmin children of Dakshina Kannada based on McNamara’s analysis. J Indian Soc Pedo Prev Dent ,June 2001 pg 41- 51 www.indiandentalacademy.com
  103. 103. Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com

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