cephalometric analysis dent 657. analysis utilizing the cephalometric tracing 1) describe the...
TRANSCRIPT
CEPHALOMETRIC ANALYSIS
DENT 657
ANALYSIS UTILIZING THE CEPHALOMETRIC TRACING
1) Describe the subject’s dento-facial morphology
2) Quantitative description of morphological deviations
3) Make diagnostic and treatment planing decisions
2) Evaluate change over time - treatment induced and growth process
Morphological Description
Skeletal - horizontal and vertical Dental - horizontal and vertical Comparing individual subject’s tracing
to the “ideal” Reference sampleCross-sectional
Longitudinal - growth studies eg. Bolton-Brush, Ann Arbor and Burlington
Cephalometric Analyses
Down’s Steiner’s Tweed’s McNamara’s OSU
Cephalometric Evaluation
Identification of anatomic landmarks Landmarks: stable reference structures
and maxillary and mandibular skeletal and dental
Graphically relating the dento-facial elements to these reference structures
Angular and or linear measurements
METHODS OF CEPHALOMETRIC ANALYSIS
Two basic approaches Metric approach - use of selected linear
and angular measures Graphic approach - “overlay” of
individual’s tracing on a reference template and visual inspection of degree of variation
Metric Method - Use of selected linear and angular measures
Graphic Method - Use of a Composite Template
GOALS OF CEPHALOMETRIC ANLYSIS
Evaluating relationships, both horizontal and vertical of 5 major functional components of the face:
the cranial base; the maxilla; the mandible, the maxillary and mandibular dento-
alveolus
REFERENCE LINES
Frankfort’s Horizontal (porion to orbitale)
Sella - Nasion line True horizontal plane True vertical plane
sella nasion
porion orbitale
Reference Lines
SKELETAL HORIZONTAL - MAXILLA
SNA 82 ± 2 deg
NA TO FH 90 ± 3 deg
SNA 82 ± 2 deg
NA TO FH 90 ± 3 deg
s n
a
F H
SKELETAL HORIZONTAL - MANDIBLE
s n
bP g
F H
SNB 80 ± 2 deg
N-PG TO FH
88 ± 6 deg
SNB 80 ± 2 deg
N-PG TO FH
88 ± 6 deg
SKELETAL HORIZONTAL - MAXILLA TO MANDIBLE
N
A
B
ANB 2 ± 2 degANB 2 ± 2 deg
SKELETAL VERTICAL
F H
S
G NM E
G O
FH TO GOGN 22 ± 5 deg
Y AXIS 59 ± 6 deg
LFH 55% OF TFH
FH TO GOGN 22 ± 5 deg
Y AXIS 59 ± 6 deg
LFH 55% OF TFH
DENTAL - UPPER TO LOWER INCISOR
INTERINCISAL 130 ± 5 deg
INTERINCISAL 130 ± 5 deg
DENTAL - MAXILLARY INCISOR
F H
N
A
U1 TO FH 110 ± 5 deg
U1 TO NA 22deg
U1 TO NA 4mm
U1 TO FH 110 ± 5 deg
U1 TO NA 22deg
U1 TO NA 4mm
DENTAL - MANDIBULAR ANTERIOR
GO
GN
B
N
L1 TO NB 25deg
L1 TO NB 4mm
L1 TO GOGN 91 ± 6deg
L1 TO NB 25deg
L1 TO NB 4mm
L1 TO GOGN 91 ± 6deg
SOFT TISSUE
NASOLABIAL ANGLE 102 ± 8 deg
L.LIP TO E PLANE -2 ±2mm
NASOLABIAL ANGLE 102 ± 8 deg
L.LIP TO E PLANE -2 ±2mm
Limitations of the Metric Method
Stable reference structures are only relatively stable
Validity of landmarks Error in landmark identification
Graphic Method
Template Changes between 2 time points
Superimposition Method - on the cranial base
Maxillary and mandibular superimposition
Limitations of Cephalometric Analysis
Individual variability Ethnic variability Gender variability