226-interpretation of cephalometric data-cepahalometric analysis-analyses cephalometriques-mohamad-aboualnaser-awatef shaar-oussama sandid-orthodontist-orthodontiste (1)pdf.pdf

155‐Cephalometric analysis
Interpretation
Part 2: Lines‐ Plans‐ Angles
O. SANDID‐ Orthodontist spécialiste qualifié en orthodontie, Paris‐France
M. ABOULNASER‐ Orthodontist, BAU, Connecticut, USA.

Cephalometric analysis
Part 2: Lines‐ Plans‐ Angles
• Lines‐ Plans‐ Angles
• SN line
• Frankfort Plane
• Mandibular Plane
• Maxillary Plane
• SNA
• SNB
• ANB
Cephalometric analysis Anatomic points
Oussama SANDID ‐ Mohamad ABOUALNASER‐ Awatef SHAAR

SN line The plane
demonstrated by a line
through the nasion and
sella
Frankfort Plane The plane
through the orbitale and
porion
Mandibular Plane
(MnPl) The plane
through the gonion and
menton. The definition
varies slightly, but the plane
is used to show the plane of
the lower border of the
mandible
Maxillary Plane (MxPl) The
plane demonstrated by a
line through the anterior
and posterior nasal spines
Lines‐ Plans‐ Angles
S
N
Po
Or
PNS
ANS
Go
M e

SN line The plane
through the nasion and
sella
Frankfort Plane The plane
through the orbitale and
porion
Mandibular Plane
(MnPl) The plane
through the gonion and
menton. The definition
varies slightly, but the plane
is used to show the plane of
the lower border of the
mandible
Maxillary Plane (MxPl) The
plane demonstrated by a
line through the anterior
and posterior nasal spines

• SN Plane =S N, The plane demonstrated by a line through the
nasion and sella
S N
S
N
S

• Frankfort Plane 1) A plane passing through three points of the right and left porion and the
left orbitale.
2) First proposed at the Craniometric Congress held in Munich, Germany, 1877.
3) An orientation of skull in a consistent and reproducible position.
4) Comparisons: natural head position; horizontal visual axis; and horizontal plane.
http://www.columbia.edu/itc/hs/medical/humanAnatomy/yuan/craniologyISlides_files/slide0062.html

• Palatal Plane PP = ANS PNS

• Occlusal Plane

• Mandibular plane MP=Go‐Me

Oussama SANDID (France)‐ Mohamad ABOUALNASER (USA)‐ ORTHODONTISTS‐ DENTISTS
LEBANON‐ FRANCE ‐USA‐pediatric dentistry lebanon‐dentistry lebanon‐

SNA (82 °) ± 3° : Represents the antero‐posterior relation between the maxilla and the cranium
Maxilla is Retrusive < 76 ‐‐‐‐‐‐‐ Or Deficient Retrognathic Maxilla
Maxilla is Average 77‐82
Maxilla is Protrusive > 83 ‐‐‐‐‐ Or Prognathic Maxilla
82 °
82 °
S N
A

SNB (80°) ± 3° Represents the antero ‐posterior relation betwwen mandible and cranium
Mandible is protrusive if > 83‐‐‐‐‐‐ Or Prognathic Mandible
Mandible is average 76‐82
Mandible is retrusive < if 75‐‐‐‐‐‐‐‐ Or Retrognathic mandible
80°
80°
S N
B

ANB = SNA ‐SNB + 2° Represents Angle’s class (I,II,III)
0 ‐ 4 Normal Class I
> 4 Class II Skeletal
< 0 Class III Skeletal
2°
2°

• SNA = Sella ‐ Nasion ‐ A point 82  3 MAXILLA to CRANIAL BASE
• This angle indicates the horizontal position of the maxilla relative to the cranial base.
• > 85 ‐ protrusive or prognathic maxilla
• < 79 ‐ deficient or retrognathic maxilla
S
N
A
82

• SNB Sella ‐ Nasion ‐ B point 79  3 MANDIBLE to CRANIAL BASE
• B‐point is the most anterior measure point of the mandibular apical base. This angle
expresses the horizontal position of the mandible relative to the cranial base using B‐point
as a cephalometric landmark.
• > 82 ‐ prognathic mandible
• <76 ‐ retrognathic mandible
S
N
B
79

• ANB A point ‐ Nasion ‐ B point 3  2 MAXILLA to MANDIBLE
The ANB angle measures the relative
position of the maxilla to mandible. The
ANB angle can be measured or calculated
from the formula: ANB = SNA ‐ SNB.
A positive ANB angle indicates that the
maxilla is positioned anteriorly relatively to
the mandible (Class I or Class II
malocclusion cases).
A negative ANB angle indicates that the
maxilla is positioned posteriorly relative to
the mandible (Class III malocclusion cases).
The normal range is 1‐5.
>5 indicates a Class II skeletal jaw
relationship, protrusive maxilla or
retrognathic mandible.
<1 indicates a Class III skeletal jaw
relationship, deficient maxilla or prognathic
mandible.

• MAXILLA TO CRANIAL BASE Na‐A point to FH = 90 ° ± 4
• > 94 ° Protrusive or prognathic maxilla.
• < 86 ° Deficient or retrognathic maxilla.
A
Na
FH Po Or
90 °

• Lower 1 to Mandibular plane‐ L1 MP‐‐ Me Go‐ i
The lower incisor inclination
Retroclined < 90 °
Average 90 ± 3 °
ProclIned > 93 °
90

• MANDIBLE to CRANIAL BASE = 80 ° ± 3
• SN‐Pg (Sella‐Nasion‐Pogonion).
• > 83 ° prognatic mandible
• < 77 ° retrognathic mandible
S
Na
Pog
80

• Inter incisal amgle = 135 °
• > 135 ° retroclination of the anterior teeth
• < 135 ° proclination of the anterior teeth
135 °

• Palatal plan to Mandibular plane PM 32 °
• Skeletal Open 33 °
• Skeletal Closed 24 °
32 °

• CRANIAL BASE DEFLEXION Basion Sella Nasion ‐SNa / BA = 129 °
• Used describe the cranial base.
• Norm 129 ° ± 5
S
Na
Ba
129 °

S Na Longeur base du crane = 72mm
‐Court
‐Long
Utlise en correlation avec SBA , SNB
S
Na
72mm

• SN‐H = 8 ° Angulation Base du crane avec plan horizontal
8 °

• Mandibular plane angle 32 ° SN‐MP
It represents vertical relation
> 32 open bite (downward and backwards rotation of the mandible)
< 32 deep bite (upward and forword rotation of the mandible)
N
S
Me
Go
32 °

• Frankfurt Mandibular plane Angle
• Skeletal open > 28 adult
• > 30 children
• Skeletal average
• 19‐27 adult
• Skeletal Closed < 20 Children
• < 18 adult

• Palatal plan to mandibular plan
• Skeletal open > 33 °
• Skeletal Average 25 ° to 32 °
• Skeletal Closed < 24 °
25 ° to 32 °

• Upper 1 to A Vertical
• Perpendicular from Frankfurt Horizontal that passes through A point + Reference line
• Measure in millimeters from the reference line to the incisal edge of the upper incisor
• Protruded > + 6
• Average + 3 to + + 5
• Retruded < + 2

• Y axis:FH‐S Gn=59 °
• It indicated the growth pattern (vertical horizontal or normal
Or
59 °

• U1/SN =116 °
• Inclination of the upper incisor in relation to cranial base
• More than 116 °:proclination upper anterior teeth
• Less than 116 °:retroclination of the upper anterior teeth
S N
116 °

226-interpretation of cephalometric data-cepahalometric analysis-analyses cephalometriques-mohamad-aboualnaser-awatef shaar-oussama sandid-orthodontist-orthodontiste (1)pdf.pdf

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