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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
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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 sample Cross-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
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
Reference Lines nasion sella porion orbitale
SNA 82 ± 2 deg NA TO FH 90 ± 3 deg SKELETAL HORIZONTAL - MAXILLA n s F H a
SNB 80 ± 2 deg N-PG TO FH 88 ± 6 deg SKELETAL HORIZONTAL - MANDIBLE n s F H b P g
ANB 2 ± 2 deg SKELETAL HORIZONTAL - MAXILLA TO MANDIBLE N A B
FH TO GOGN 22 ± 5 deg Y AXIS 59 ± 6 deg LFH 55% OF TFH SKELETAL VERTICAL S F H G O G N M E
INTERINCISAL 130 ± 5 deg DENTAL - UPPER TO LOWER INCISOR
U1 TO FH 110 ± 5 deg U1 TO NA 22deg U1 TO NA 4mm DENTAL - MAXILLARY INCISOR N F H A
L1 TO NB 25deg L1 TO NB 4mm L1 TO GOGN 91 ± 6deg DENTAL - MANDIBULAR ANTERIOR N GO B GN
NASOLABIAL ANGLE 102 ± 8 deg L.LIP TO E PLANE -2 ±2mm SOFT TISSUE
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
Limitations of Cephalometric Analysis • Individual variability • Ethnic variability • Gender variability