INDIAN DENTAL ACADEMY
Leader in continuing dental education
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INTRODUCTION:
Cephalometrics has given us a different
prespective of interpreting various skeletal
problems in the dentofa...
Limitations of cephalometry:
 Errors of projection:
Magnification
Distortion
 Errors of identification
Radiograph qualit...
Errors due to
1.use of intracranial reference planes
2.patient positioning in the cephalostat
www.indiandentalacademy.com
Intracranial reference planes:
 Indv. variations in
reference lines -
different
interpretation of
subjects with
similar p...
 Variations in the reln. bet. reference lines -
different evaluation of facial skeletal
pattern
 Does not always reflect...
www.indiandentalacademy.com
CAMPER’S LINE:
First orientation plane to orient cranium
on a horizontal from the middle of EAM
to ANS
www.indiandentalaca...
Sella- Nasion Plane :
 Antero posterior extent of ant. cranial base.
 Steiner – the S & N points move only
minimally whe...
Inclination of SN plane:
Bjork AO 1951 – earliest to report unreliability
Drawbacks of S-N plane:
Downward- facial
angles...
Mcnamara AO 1981 – Cephalometric
maxillary retrusion in cl.II cases is due to low
inclination of the skull base
www.indian...
The anterior skull base (S-N) is unstable in
growing persons.
• Nasion - landmark on an actively growing suture,
- moves ...
• The S-N line may therefore rotate
slightly over time - results in a
considerable back or forward swing of
the chin.
www....
Sella is totally unrelated to the structures of
the face and therefore cannot be used to
measure facial development
( ELL...
Frankfort horizontal plane
The plane through left and right porion and left
orbitale , (in 1884 by craniologists), - the b...
Drawbacks of FH plane:
Downs(1956) - the discrepancies between
Cephalometric and photographic facial
typing disappear whe...
www.indiandentalacademy.com
Anatomical location of porion
Machine porion
Anatomic porion
Individual variation
Vertical relationships with other
int...
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Occlusal plane:
Drawn thru’ the region of overlapping cusps
of I premolar & I molars (Jacobson Wit’s
Appraisal)
• To elim...
Disadvantages:
• Affected by occlusal plane angle & vertical
alveolar relationships
• Affected by vertical distance betwee...
• Any change in occlusal plane during treatment
allows variation
• Growth related changes cannot be determined
www.indiand...
Patient positioning in a
cephalogram:
Patient aligned within ear rods of the
cephalostat exerting moderate pressure on
EA...
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Disadvantage of ear rods:
Greenfield et.al. AJO 1989
Fixed position of cephalostat - cannot be
adjusted forward, backward...
If the transmeatal axis is not perpendicular
to the midsagittal plane- immobilization of
the head with ear rods introduce...
www.indiandentalacademy.com
Definition :
AJO 1994 Moorrees
- A standardized and reproducible
position of the head, in an upright
posture, the eyes foc...
Advantages of NHP:
It provides the use of an extracranial
reference line (true vertical or horizontal) for
cephalometric ...
www.indiandentalacademy.com
The natural head position is relatively
constant over time.
(MOORREES &KEAN 1958)
Facial photograph and cephalometric
ra...
Natural head posture:
Developed by Molhave for studying the
biodynamics of the human body.
Natural head posture is a phy...
defined as a small range of positions
oscillating around the subject's mean NHP.
(Lundstrom EJO 1991)
Head posture is a ...
Postural control of the head is influenced by
Resistance to gravity
Respiration
Deglutition
Sight (visual axis)
Vesti...
For Cephalometric analysis, the
standardized NHP is preferable to
natural head posture
(MOORREES)
www.indiandentalacademy....
Ortho position:
―The momentary interim position when
taking the first step forward from a
standing to a moving or walking...
NATURAL HEAD ORIENTATION:
― The head orientation of the subject perceived
by the clinician, based on general
experience, a...
Lundström and Lundström AJO1995
The NHO related horizontal line
standardized to a line through Sella is the
best reference...
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Readily registered by instructing the subject
standing or sitting in the cephalostat to look
at a point on the wall in fr...
•The wire plumb line –
record the true vertical
Plumb line bisects the
reflection of the subject's
face in the mirror and
...
The location of the central
x-ray beam -determined by
a projected light cross
("+").
Magnification
standardized by the
plu...
To prevent the swaying , define the feet
position as "a comfortable distance
apart and slightly diverging―
(Cooke 1986)
ww...
Solow & Tallgren
Acta Odontol. Scand. 1971
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REHEARSAL PHASE:
• Patients placed facing a neutral wall (nothing
to distract ).
• Carefully observe the patient's posture...
BODY POSTURE.
Mølhave(1958) -the most reproducible natural
standing position is the orthoposition
Small children - to pla...
HEAD POSTURE. - two methods
(SOLOW 1971)
 The subject's own feeling of a natural
head position ―the self-balance position...
 Positioning according to external reference -
carried out only after the head has been
placed in the self-balance positi...
www.indiandentalacademy.com
If the earrods are not
aligned, place the
operator’s foot in front
of or behind the patient's
feet and ask the patient
to ...
BODY-POSITIONING &
HEAD-POSITIONING.
Patient instructed to
''hold your head so that
you can look into your
own eyes in the...
THE FLUID LEVEL DEVICE
AJO 1983 Showfety et.al
The ends of the air bubble aligned with the
ends of an 0.030 inch diameter...
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The ideal location - between the eyebrow and
the hairline behind the prominent temporal
crest of the frontal bone.
The pat...
The patient is placed in the cephalometric head
holder & the patient's head is tilted up or
down until the bubble is align...
www.indiandentalacademy.com
Inclinometer
AJO 1991 Murphy et.al.
 uses a contactless precision potentiometer to
continuously measure changes in inclin...
www.indiandentalacademy.com
www.indiandentalacademy.com
AJO1985 Archer and Vig
Wood 1981
Leveling device consisting
of a fluid-filled plastic
ring mounted on a
protractor.
www.in...
Other methods:
• Schmidt (1876) made use of a frame that encircled
the skull, a plumb line and a protractor.
• Moorrees an...
• Cinefluorography may be used to measure
head posture over a period but exposes
subjects to irradiation for relatively lo...
Importance of NHP:
(Solow and Kreiborg 1977)
―Soft tissue stretching hypothesis''
Head extension - stretch of the soft tis...
Extended head posture –
Facial retrognathism
Retroclination of lower incisors
AFH and PFH
A-P craniofacial dimension
Large...
RESPIRATION &NHP
• Woodside and Linder-Aronson(EJO1976)
- children with nasal obstruction had a more
extended head posture...
• Oral respiration - produce an altered
mandibular posture and changes in the shape
of the mandible with development of an...
Nasal obstruction
Craniocervical postural adaptations
Mandibular postural adaptation
Skeletal growth modification
Dentoalv...
Dentoalveolar height and occlusal plane
inclination showed a set of positive
correlations with the craniocervical and sell...
Goldstein and associates(1984)
 Evaluated the mandibular trajectory of
closure with a mandibular kinesiograph
 Four post...
• Alterations of the A-P head and neck posture
have an immediate effect on the trajectory of
mandibular closure.
• As the ...
DESCRIPTION OF HEAD AND NECK
POSITION ON THE RADIOGRAPH
SOLOW &TALLGREN(1976)
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NSL/OPT - represent tilting of the head at
occipitoatloid joint
OPT/CVT -represent change in cervical
curvature
OPT/HOR...
Large craniocervical angle- an extension of the
head -the height of the posterior arc of the
atlas is reduced
-Also relate...
Various analysis using
NHP:
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Reference planes in NHP:
Down’s & Tweed-
Drop perpendicular thru’ Orbitale
Test difference between true horizontal & FH
& ...
Growth prediction from posture
Solow & Nielson AJO 1992
41 reference points and 4 fiducial points
www.indiandentalacademy....
Points N and S on the first film - fiducial
points in the anterior cranial base- REFcrb.
In the mandible - fiducial poin...
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A backward inclination of the cervical column
& small craniocervical angle
 reduced backward displacement of TMJ
 increa...
Upright position of the cervical column &
large craniocervical angle
 large backward displacement of TMJ
 reduced growth...
A small craniocervical angle was associated
with a horizontal facial growth pattern
A large craniocervical angle was ass...
Five-factor cephalometric
summary analysis
Horizontal line Reference-
 drawn parallel to the border of the radiograph
con...
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Angle 1 - anteroinferior angle bet. Y axis &
true horizontal.
Angle 2 - angle bet. upper incisor & true
horizontal.
Angle ...
"Normal" AB/horizontal values for clinical use
 Skeletal Class I 12° to 18°
 Skeletal Class II > 18°
 Skeletal Class II...
Advantages:
Requires no new sets of "norms" or figures.
 Only the reference plane has been changed
to eliminate the erro...
Normal - focus on the profile from the nose
down
The A-P position of the forehead -not a major
factor
The size of the n...
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A line drawn through
the middle of the nose
(No), parallel to the true
vertical- the ― V‖ line.
The ― V‖ angle - the
angle...
FCA - + 3° prognathic
― E‖ line -normal lower
lip
V‖ angle - -1.5° -
supports clinical
impression of prognathic
profile .
...
FCA - -8° indicates
retrognathic profile.
― E‖ line I- retrusive
― V‖ angle - -11° in
accordance with
clinical impression ...
Cephalometric Analysis based on
NHP: JCO 1991 VIAZIS
Defines the A-P & vertical position of the
maxilla and mandible rela...
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Comprehensive Assessment of
Anteroposterior Jaw Relationships
JCO1992 VIAZIS
Describe an assessment of the
anteroposterior...
 Size of Mand. relative to Ant. Cranial Base (SN-
GoGn)
 Maxillomandibular Ratio (PNS-ANS:ArGn)
 Linear and Angular Mea...
1. Size of Mandible Relative to Anterior
Cranial Base (SN-GoGn)
1:1 ratio -indicate a
well-balanced mandible
relative to ...
2. Maxillomandibular Ratio (PNS-
ANS:ArGn)
The length of the
mandible is exactly
double the length of
the maxilla for all...
3. Linear and Angular Measurements (A,
B, Pg to N^TH; NA, NB, NPg to TH)
Three linear measurements— from A, B,
and Pg to ...
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4. Relative Anteroposterior Position (TH
Wits and ANB)  Points A and B
projected on
perpendiculars to
TH, (a and b). The
...
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5. Anteroposterior Chin Position
(Chin Length and BNPg)
The BNPg angle
assesses the
prominence of
the chin relative
to th...
 Projections of B and
Pg to a line parallel
to TH and tangent
to the mandible at
menton define the
chin length,- bp
www.i...
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Optic plane: SASSOUNI
the supraorbitale plane (a line tangent to
anterior clinoid and the roof of the orbit)
the infraor...
Natural head position in
photographs
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Camera - mounted on a tripod & leveled with
the optical axis of the lens horizontal and the
film plane vertical.
20 × 100 ...
Assume and maintain a "natural and normal"
erect posture of head and shoulders, with
both arms hanging free beside the tr...
AJO 1994 Ferrario et.al.,
Developed a photographic technique -
associated with standard radiograph &
a computerized metho...
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the angle between the N'-Pg' line and the true
vertical was calculated on the photograph &
cephalometric films
The diffe...
 Angle N'-Pg' line/true
vertical was fed to a
computer program -
provided a rotation of all
the landmarks until the
cepha...
Craniofacial morphometry by
photographic evaluation
AJO 1993 –Ferrario et.al.
 Frontal standing, rest & clenching a Fox p...
 Median points -soft tissue nasion ,nasal
apex ,soft tissue subnasale ,upper lip ,lower
lip ,soft tissue pogonion .
 Lat...
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 Face center of gravity (CG) coordinates--- used as
the new origin of coordinate axes - the points
were translated.
on th...
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A proportional analysis of the soft
tissue facial profile
Lundström et.al, AO 1992
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DISADVANTAGE OF NHP
AJO 1980 Frankel
 Functional appliance treatment- changes in
posture ( functional and physiologic)- d...
Did not consider NHP modifications
during treatment, but proposed to refer all
longitudinal radiograms to the first NHP
re...
CONCLUSION:
― THE SEARCH FOR AN IDEAL‖
-Cephalometrics is constantly undergoing
refinements in its techniques & analyses t...
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Natural head position

Published on: Mar 3, 2016
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Transcripts - Natural head position

  • 1. INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  • 2. INTRODUCTION: Cephalometrics has given us a different prespective of interpreting various skeletal problems in the dentofacial complex. However, the promise of the cephalometrics as a diagnostic and prognostic tool is yet to be fulfilled. www.indiandentalacademy.com
  • 3. Limitations of cephalometry:  Errors of projection: Magnification Distortion  Errors of identification Radiograph quality Reproducibility  Unpredictability of growth  Limitations in suerimpositioning methodswww.indiandentalacademy.com
  • 4. Errors due to 1.use of intracranial reference planes 2.patient positioning in the cephalostat www.indiandentalacademy.com
  • 5. Intracranial reference planes:  Indv. variations in reference lines - different interpretation of subjects with similar profiles. www.indiandentalacademy.com
  • 6.  Variations in the reln. bet. reference lines - different evaluation of facial skeletal pattern  Does not always reflect the clinical appearance of the individual subject. www.indiandentalacademy.com
  • 7. www.indiandentalacademy.com
  • 8. CAMPER’S LINE: First orientation plane to orient cranium on a horizontal from the middle of EAM to ANS www.indiandentalacademy.com
  • 9. Sella- Nasion Plane :  Antero posterior extent of ant. cranial base.  Steiner – the S & N points move only minimally when head deviates from the true profile position & even when head is rotated in the cephalostat www.indiandentalacademy.com
  • 10. Inclination of SN plane: Bjork AO 1951 – earliest to report unreliability Drawbacks of S-N plane: Downward- facial angles decrease Upward- facial angles increase www.indiandentalacademy.com
  • 11. Mcnamara AO 1981 – Cephalometric maxillary retrusion in cl.II cases is due to low inclination of the skull base www.indiandentalacademy.com
  • 12. The anterior skull base (S-N) is unstable in growing persons. • Nasion - landmark on an actively growing suture, - moves forward, upward, or downward in growing children • Sella- its geometric center is unstable since the pituitary gland enlarges during growth. www.indiandentalacademy.com
  • 13. • The S-N line may therefore rotate slightly over time - results in a considerable back or forward swing of the chin. www.indiandentalacademy.com
  • 14. Sella is totally unrelated to the structures of the face and therefore cannot be used to measure facial development ( ELLIS & MC NAMARA) www.indiandentalacademy.com
  • 15. Frankfort horizontal plane The plane through left and right porion and left orbitale , (in 1884 by craniologists), - the best compromise for orientation of crania. www.indiandentalacademy.com
  • 16. Drawbacks of FH plane: Downs(1956) - the discrepancies between Cephalometric and photographic facial typing disappear when a correction is made for those persons in whom the "Frankfurt plane" is not horizontal. www.indiandentalacademy.com
  • 17. www.indiandentalacademy.com
  • 18. Anatomical location of porion Machine porion Anatomic porion Individual variation Vertical relationships with other intracranial landmarks – biologic variation www.indiandentalacademy.com
  • 19. www.indiandentalacademy.com
  • 20. Occlusal plane: Drawn thru’ the region of overlapping cusps of I premolar & I molars (Jacobson Wit’s Appraisal) • To eliminate the effect of rotation of the jaws • Variation in the A-P relation of the jaws with respect to cranium www.indiandentalacademy.com
  • 21. Disadvantages: • Affected by occlusal plane angle & vertical alveolar relationships • Affected by vertical distance between points A & B www.indiandentalacademy.com
  • 22. • Any change in occlusal plane during treatment allows variation • Growth related changes cannot be determined www.indiandentalacademy.com
  • 23. Patient positioning in a cephalogram: Patient aligned within ear rods of the cephalostat exerting moderate pressure on EAM. Patient’s FH placed parallel to the floor canthomeatal line placed 10 degrees to floor Locking nasal positioner against bridge of nose www.indiandentalacademy.com
  • 24. www.indiandentalacademy.com
  • 25. Disadvantage of ear rods: Greenfield et.al. AJO 1989 Fixed position of cephalostat - cannot be adjusted forward, backward, sidewise, or rotated. - The subject moves his head to fit the ear rods, ( altering the angulation of the head and neck ). www.indiandentalacademy.com
  • 26. If the transmeatal axis is not perpendicular to the midsagittal plane- immobilization of the head with ear rods introduces asymmetry Moorrees and Kean(1958). www.indiandentalacademy.com
  • 27. www.indiandentalacademy.com
  • 28. Definition : AJO 1994 Moorrees - A standardized and reproducible position of the head, in an upright posture, the eyes focused on a point in the distance at eye level, which implies that the visual axis is horizontal. www.indiandentalacademy.com
  • 29. Advantages of NHP: It provides the use of an extracranial reference line (true vertical or horizontal) for cephalometric analysis. NHP should be the preferred for profile evaluation as it reflects the everyday true life appearance of people. (COOKE 1986) www.indiandentalacademy.com
  • 30. www.indiandentalacademy.com
  • 31. The natural head position is relatively constant over time. (MOORREES &KEAN 1958) Facial photograph and cephalometric radiograph in NHP - direct correlation bet. real-life appearance and tracing. www.indiandentalacademy.com
  • 32. Natural head posture: Developed by Molhave for studying the biodynamics of the human body. Natural head posture is a physiologic position -"orthoposition" - characteristic for a person and reproducible, but differs among persons. www.indiandentalacademy.com
  • 33. defined as a small range of positions oscillating around the subject's mean NHP. (Lundstrom EJO 1991) Head posture is a dynamic concept and ideally its measuration should be performed in a dynamic and continuous manner. www.indiandentalacademy.com
  • 34. Postural control of the head is influenced by Resistance to gravity Respiration Deglutition Sight (visual axis) Vestibular balance mechanism Hearing www.indiandentalacademy.com
  • 35. For Cephalometric analysis, the standardized NHP is preferable to natural head posture (MOORREES) www.indiandentalacademy.com
  • 36. Ortho position: ―The momentary interim position when taking the first step forward from a standing to a moving or walking posture.― Ortho position is the most reproducible habitual symmetrical standing position. Solow and Tallgren www.indiandentalacademy.com
  • 37. NATURAL HEAD ORIENTATION: ― The head orientation of the subject perceived by the clinician, based on general experience, as the NHP in a standing, relaxed body and head posture, when the subject is looking at a distant point at eye level.‖ www.indiandentalacademy.com
  • 38. Lundström and Lundström AJO1995 The NHO related horizontal line standardized to a line through Sella is the best reference for clinical cephalometric analysis when head positions registered at NHP are unnaturally flexed www.indiandentalacademy.com
  • 39. www.indiandentalacademy.com
  • 40. www.indiandentalacademy.com
  • 41. Readily registered by instructing the subject standing or sitting in the cephalostat to look at a point on the wall in front, exactly at eye level. A small mirror (diameter no more than 10 cm), the midpoint of which also at eye level, can be used also for head orientation. www.indiandentalacademy.com
  • 42. •The wire plumb line – record the true vertical Plumb line bisects the reflection of the subject's face in the mirror and minimize lateral head rotation. www.indiandentalacademy.com
  • 43. The location of the central x-ray beam -determined by a projected light cross ("+"). Magnification standardized by the plumb line bisecting the reflection of the subject's face in the mirror. www.indiandentalacademy.com
  • 44. To prevent the swaying , define the feet position as "a comfortable distance apart and slightly diverging― (Cooke 1986) www.indiandentalacademy.com
  • 45. Solow & Tallgren Acta Odontol. Scand. 1971 www.indiandentalacademy.com
  • 46. REHEARSAL PHASE: • Patients placed facing a neutral wall (nothing to distract ). • Carefully observe the patient's posture before the actual rehearsal takes place, • The patient walks from the waiting area to the radiographic room. www.indiandentalacademy.com
  • 47. BODY POSTURE. Mølhave(1958) -the most reproducible natural standing position is the orthoposition Small children - to place heels together and let the arms hang. Older and tense patients - "walk on the spot'' & to raise and drop shoulders to ease tension. www.indiandentalacademy.com
  • 48. HEAD POSTURE. - two methods (SOLOW 1971)  The subject's own feeling of a natural head position ―the self-balance position.‖  Based on visual cues from external reference www.indiandentalacademy.com
  • 49.  Positioning according to external reference - carried out only after the head has been placed in the self-balance position.  In adults the head is kept, on the average, 3 degrees higher in the mirror position than in the self-balance position. www.indiandentalacademy.com
  • 50. www.indiandentalacademy.com
  • 51. If the earrods are not aligned, place the operator’s foot in front of or behind the patient's feet and ask the patient to move slightly until he hits the operator's foot POSITIONING OF THE FEET. www.indiandentalacademy.com
  • 52. BODY-POSITIONING & HEAD-POSITIONING. Patient instructed to ''hold your head so that you can look into your own eyes in the miror". ADJUSTMENT FOR SYMMETRY. carried out with guidance by the light-beam cross www.indiandentalacademy.com
  • 53. THE FLUID LEVEL DEVICE AJO 1983 Showfety et.al The ends of the air bubble aligned with the ends of an 0.030 inch diameter wire The fluid consists of a mixture of radiopaque liquid, blue dye, and a silicone suspension, rendering the air bubble visible on the cephalometric radiograph. www.indiandentalacademy.com
  • 54. www.indiandentalacademy.com
  • 55. www.indiandentalacademy.com
  • 56. www.indiandentalacademy.com
  • 57. The ideal location - between the eyebrow and the hairline behind the prominent temporal crest of the frontal bone. The patient instructed to stand in an ''intention position‖. The fluid level is rotated on the pivot until the bubble is aligned with the ends of the wire. PROCEDURE: www.indiandentalacademy.com
  • 58. The patient is placed in the cephalometric head holder & the patient's head is tilted up or down until the bubble is aligned with the wire. A vertical reference chain & wire in the fluid- level device will be aligned at 90 degrees to each other www.indiandentalacademy.com
  • 59. www.indiandentalacademy.com
  • 60. Inclinometer AJO 1991 Murphy et.al.  uses a contactless precision potentiometer to continuously measure changes in inclination around a single axis of rotation  the inclinometer was calibrated  Spectacles attach the inclinometer to the head in a stable manner . www.indiandentalacademy.com
  • 61. www.indiandentalacademy.com
  • 62. www.indiandentalacademy.com
  • 63. AJO1985 Archer and Vig Wood 1981 Leveling device consisting of a fluid-filled plastic ring mounted on a protractor. www.indiandentalacademy.com
  • 64. Other methods: • Schmidt (1876) made use of a frame that encircled the skull, a plumb line and a protractor. • Moorrees and Kean projected the image of a plumb line of stainless steel ligature wire onto cephalometric radiographs • Von Baer and Wagner instructed subjects to look directly at the reflection of their eyes on a a mirror fixed to a wall. www.indiandentalacademy.com
  • 65. • Cinefluorography may be used to measure head posture over a period but exposes subjects to irradiation for relatively long periods.(Cleall et.al., AO 1966) www.indiandentalacademy.com
  • 66. Importance of NHP: (Solow and Kreiborg 1977) ―Soft tissue stretching hypothesis'' Head extension - stretch of the soft tissues - increase in the forces of the lips and other faciocervical muscles . www.indiandentalacademy.com
  • 67. Extended head posture – Facial retrognathism Retroclination of lower incisors AFH and PFH A-P craniofacial dimension Larger inclination of the mandible to SN Larger cranial base angle Small nasopharyngeal space SOLOW & TALLGREN 1976 www.indiandentalacademy.com
  • 68. RESPIRATION &NHP • Woodside and Linder-Aronson(EJO1976) - children with nasal obstruction had a more extended head posture(6°) . • Extended head posture after induced mouth breathing - Hellsing et.al.,(EJO1987) www.indiandentalacademy.com
  • 69. • Oral respiration - produce an altered mandibular posture and changes in the shape of the mandible with development of an anterior open-bite (Harvold et.al.,1973) www.indiandentalacademy.com
  • 70. Nasal obstruction Craniocervical postural adaptations Mandibular postural adaptation Skeletal growth modification Dentoalveolar compensation/adaptation www.indiandentalacademy.com
  • 71. Dentoalveolar height and occlusal plane inclination showed a set of positive correlations with the craniocervical and sella -nasion to vertical angulations (SOLOW &TALLGREN 1977) www.indiandentalacademy.com
  • 72. Goldstein and associates(1984)  Evaluated the mandibular trajectory of closure with a mandibular kinesiograph  Four postural attitudes: natural sitting posture (NP), forward head posture (FHP), maximal forward head posture (MFHP), and military posture (MP). www.indiandentalacademy.com
  • 73. • Alterations of the A-P head and neck posture have an immediate effect on the trajectory of mandibular closure. • As the head moved anteriorly - the vertical distance of mandibular closure decreased. • When the head moved posteriorly - the anterior excursion of the mandible through the interocclusal space decreased.www.indiandentalacademy.com
  • 74. DESCRIPTION OF HEAD AND NECK POSITION ON THE RADIOGRAPH SOLOW &TALLGREN(1976) www.indiandentalacademy.com
  • 75. www.indiandentalacademy.com
  • 76. NSL/OPT - represent tilting of the head at occipitoatloid joint OPT/CVT -represent change in cervical curvature OPT/HOR & CVT/HOR- Cervical inclination in relation to the true horizontal NSL/VERT -the total change in head position www.indiandentalacademy.com
  • 77. Large craniocervical angle- an extension of the head -the height of the posterior arc of the atlas is reduced -Also related to adenoid airway obstruction and a vertical facial development (Huggare et.al., EJO 1985) www.indiandentalacademy.com
  • 78. Various analysis using NHP: www.indiandentalacademy.com
  • 79. Reference planes in NHP: Down’s & Tweed- Drop perpendicular thru’ Orbitale Test difference between true horizontal & FH & include in the analyses Bjork & Steiner- Draw horizontal thru’ nasion S-N made 10 degrees to horizontal www.indiandentalacademy.com
  • 80. Growth prediction from posture Solow & Nielson AJO 1992 41 reference points and 4 fiducial points www.indiandentalacademy.com
  • 81. Points N and S on the first film - fiducial points in the anterior cranial base- REFcrb. In the mandible - fiducial points located arbitrarily in the middle of the symphysis and one below the first molars- REFml. www.indiandentalacademy.com
  • 82. www.indiandentalacademy.com
  • 83. www.indiandentalacademy.com
  • 84. A backward inclination of the cervical column & small craniocervical angle  reduced backward displacement of TMJ  increased growth in maxillary length,  increase in max. and mand. prognathism,  forward true rotation of the mandible . www.indiandentalacademy.com
  • 85. Upright position of the cervical column & large craniocervical angle  large backward displacement of TMJ  reduced growth in maxillary length  reduction of max.and mand. Prognathism  less forward true rotation of the mandible www.indiandentalacademy.com
  • 86. A small craniocervical angle was associated with a horizontal facial growth pattern A large craniocervical angle was associated with a vertical facial development. www.indiandentalacademy.com
  • 87. Five-factor cephalometric summary analysis Horizontal line Reference-  drawn parallel to the border of the radiograph constructed at right angles to the registered true vertical.  drawn in any vertical position.  BEST -close to the Frankfort plane Cooke and Wei AJO 1988 www.indiandentalacademy.com
  • 88. www.indiandentalacademy.com
  • 89. Angle 1 - anteroinferior angle bet. Y axis & true horizontal. Angle 2 - angle bet. upper incisor & true horizontal. Angle 3 - NHP equivalent of the facial angle Angle 4 - angle bet. AB line & true horizontal. Angle 5 - angulation of the lower incisor & true horizontal.www.indiandentalacademy.com
  • 90. "Normal" AB/horizontal values for clinical use  Skeletal Class I 12° to 18°  Skeletal Class II > 18°  Skeletal Class III < 12° www.indiandentalacademy.com
  • 91. Advantages: Requires no new sets of "norms" or figures.  Only the reference plane has been changed to eliminate the errors inherent in analyses. Conventional methods are subject to errors in describing true life appearance. www.indiandentalacademy.com
  • 92. Normal - focus on the profile from the nose down The A-P position of the forehead -not a major factor The size of the nose -alter clinician's impression of the convexity of the profile & the position of the lips. A new measurement of profile esthetics JCO, 1991 VIAZIS www.indiandentalacademy.com
  • 93. www.indiandentalacademy.com
  • 94. A line drawn through the middle of the nose (No), parallel to the true vertical- the ― V‖ line. The ― V‖ angle - the angle between this line and Steiner's ― S‖ line. for adults - -12.5° for adolescents -13.0 ° www.indiandentalacademy.com
  • 95. FCA - + 3° prognathic ― E‖ line -normal lower lip V‖ angle - -1.5° - supports clinical impression of prognathic profile . www.indiandentalacademy.com
  • 96. FCA - -8° indicates retrognathic profile. ― E‖ line I- retrusive ― V‖ angle - -11° in accordance with clinical impression of orthognathic profile. www.indiandentalacademy.com
  • 97. Cephalometric Analysis based on NHP: JCO 1991 VIAZIS Defines the A-P & vertical position of the maxilla and mandible relative to the true horizontal plane, then relates the position of the dentition to its skeletal substrate. Only two soft-tissue measurements. No linear measurements. www.indiandentalacademy.com
  • 98. www.indiandentalacademy.com
  • 99. www.indiandentalacademy.com
  • 100. Comprehensive Assessment of Anteroposterior Jaw Relationships JCO1992 VIAZIS Describe an assessment of the anteroposterior position of the jaws based on measurements that use TH as their reference line. www.indiandentalacademy.com
  • 101.  Size of Mand. relative to Ant. Cranial Base (SN- GoGn)  Maxillomandibular Ratio (PNS-ANS:ArGn)  Linear and Angular Measurements (A, B, Pg to N^TH; NA, NB, NPg to TH)  Relative A-P Position ( TH Wits & ANB)  Anteroposterior Chin Position (Chin Length and BNPg) www.indiandentalacademy.com
  • 102. 1. Size of Mandible Relative to Anterior Cranial Base (SN-GoGn) 1:1 ratio -indicate a well-balanced mandible relative to the cranial base . SN should be 0- 5mm greater than GoGn before puberty, and about 0-5mm less than GoGn after puberty. www.indiandentalacademy.com
  • 103. 2. Maxillomandibular Ratio (PNS- ANS:ArGn) The length of the mandible is exactly double the length of the maxilla for all age groups and both sexes www.indiandentalacademy.com
  • 104. 3. Linear and Angular Measurements (A, B, Pg to N^TH; NA, NB, NPg to TH) Three linear measurements— from A, B, and Pg to nasion perpendicular to TH The angles between NA and NPg and TH - evaluate the anteroposterior position of the jaws . NB provides an additional assessment www.indiandentalacademy.com
  • 105. www.indiandentalacademy.com
  • 106. 4. Relative Anteroposterior Position (TH Wits and ANB)  Points A and B projected on perpendiculars to TH, (a and b). The distance ab - "TH Wits‖ - provides a clearer picture of the anteroposterior relationship of the jaws www.indiandentalacademy.com
  • 107. www.indiandentalacademy.com
  • 108. 5. Anteroposterior Chin Position (Chin Length and BNPg) The BNPg angle assesses the prominence of the chin relative to the body of the mandible www.indiandentalacademy.com
  • 109.  Projections of B and Pg to a line parallel to TH and tangent to the mandible at menton define the chin length,- bp www.indiandentalacademy.com
  • 110. www.indiandentalacademy.com
  • 111. Optic plane: SASSOUNI the supraorbitale plane (a line tangent to anterior clinoid and the roof of the orbit) the infraorbital plane (line tangent to the inferior of sella turcica and the floor of the orbit)  bisect the angle formed by their intersection - the optic plane www.indiandentalacademy.com
  • 112. Natural head position in photographs www.indiandentalacademy.com
  • 113. Camera - mounted on a tripod & leveled with the optical axis of the lens horizontal and the film plane vertical. 20 × 100 cm mirror mounted at eye level on the wall Subject – camera –150 cm 2.55 m. Mirror- subject – 120cm. Recording of NHP: www.indiandentalacademy.com
  • 114. Assume and maintain a "natural and normal" erect posture of head and shoulders, with both arms hanging free beside the trunk. On each photograph, a reference line placed perpendicular to the ground by using a small spirit level (true vertical) was drawn. www.indiandentalacademy.com
  • 115. AJO 1994 Ferrario et.al., Developed a photographic technique - associated with standard radiograph & a computerized method allowing an easy and fast superimposition of the two recordings was introduced www.indiandentalacademy.com
  • 116. www.indiandentalacademy.com
  • 117. the angle between the N'-Pg' line and the true vertical was calculated on the photograph & cephalometric films The difference - compute the position of the soft and hard tissue Frankfurt planes, and of the sella-nasion plane in NHP. These new values were compared with the values observed in the standard cephalometric orientation. www.indiandentalacademy.com
  • 118.  Angle N'-Pg' line/true vertical was fed to a computer program - provided a rotation of all the landmarks until the cephalometric N'-Pg' line coincided with the photographic one. Rotation was performed around the Bolton point www.indiandentalacademy.com
  • 119. Craniofacial morphometry by photographic evaluation AJO 1993 –Ferrario et.al.  Frontal standing, rest & clenching a Fox plane  Lateral standing, rest &clenching a Fox plane  Lateral sitting, rest 16 points were located by careful inspection & palpation and traced on the face of each subject www.indiandentalacademy.com
  • 120.  Median points -soft tissue nasion ,nasal apex ,soft tissue subnasale ,upper lip ,lower lip ,soft tissue pogonion .  Lateral points - supraorbital foramen , infraorbital foramen , soft tissue orbitale , soft tissue gonion . www.indiandentalacademy.com
  • 121. www.indiandentalacademy.com
  • 122.  Face center of gravity (CG) coordinates--- used as the new origin of coordinate axes - the points were translated. on the frontal image using the areas of eyes ,nose and mouth on the lateral image as center of the polygon N- Pog-Go-Tr  In the frontal plot, the N-CG axis -used as a new reference y-axis - points were rotated. www.indiandentalacademy.com
  • 123. www.indiandentalacademy.com
  • 124. www.indiandentalacademy.com
  • 125. A proportional analysis of the soft tissue facial profile Lundström et.al, AO 1992 www.indiandentalacademy.com
  • 126. www.indiandentalacademy.com
  • 127. www.indiandentalacademy.com
  • 128. DISADVANTAGE OF NHP AJO 1980 Frankel  Functional appliance treatment- changes in posture ( functional and physiologic)- distorts data base  Fu.A. alters muscle form and function. Adjoining muscle groups experience reciprocal changes and treatment-related head posture changes could result. www.indiandentalacademy.com
  • 129. Did not consider NHP modifications during treatment, but proposed to refer all longitudinal radiograms to the first NHP recording – missed the important information. Ferrario et.al., AJO 1994 www.indiandentalacademy.com
  • 130. CONCLUSION: ― THE SEARCH FOR AN IDEAL‖ -Cephalometrics is constantly undergoing refinements in its techniques & analyses to improve the clinical applications. NHP , a long proposed modification, yet not fully into practice, can be an ―ideal‖ reference for us to improve our cephalometric interpretation…… www.indiandentalacademy.com
  • 131. www.indiandentalacademy.com
  • 132. www.indiandentalacademy.com For more details please visit www.indiandentalacademy.com

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