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INTRODUCTION
A Cephalometric analysis especially designed for the patient who requires maxillofacial surgery was developed to use landmarks and measurements that can be altered by common surgical procedures. www.indiandentalacademy.com
SYNOPSIS • •
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Selection of x-rays Burstone analysis Hard tissue analysis Soft tissues analysis Other parameters Advantages and limitations Conclusion
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OTHER PARAMETERS Hard tissue: • SNA • SNB • ANB • FACIAL AXIS ANGLE • CHIN POSITION (AP) • INTERINCISAL ANGLE GRUMMONS ANALYSIS (PA CEPH) www.indiandentalacademy.com
OTHER PARAMETERS (CONTD..) SOFT TISSUE: GLABELLA PERPENDICULAR TO U1 SUBNASALAE PERPENDICULAR / VERTICAL (TRUE VERTICAL) ZERO MERIDIAN (SOFT TISSUE NASIONPERPENDICULAR) – CHIN-LIPNOSE- BALANCE www.indiandentalacademy.com
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BURSTONE HARD TISSUE ANALYSIS
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TRACING AND LAND MARKS
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PLANES • • • • •
SN PLANE HP PLANE PALATAL PLANE OCCLUSAL PLANE MANDIBULAR PLANE • Constructed points like Gnathion & Gonion www.indiandentalacademy.com
CRANIAL BASE Length of cranial base is measured from Articulare to nasion parallel to HP • Ar-Ptm • Ptm-N
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Ar-PTM • Ar-PTM is measured parallel to HP to determine the horizontal distance between the posterior aspects of mandible and maxilla. • Male – 37.1 +/- 2.8 • Female – 32.8+/-1.9 • Increase or decrease in these values indicates prognathism/retrognathism www.indiandentalacademy.com
Constructions of Ar-PTM
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PTM-N MALE
52.8 +/- 4.1
FEMALE
50.9 +/- 3
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HORIZONTAL SKELETAL PROFILE ANALYSIS In this analysis all measurements are made parallel to HP N-A-Pg(angle) N-A (Linear) N-B (Linear) N-Pg (Linear)
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N-A-PG(ANGLE) • This measurement indicates the degree of skeletal convexity • Male – 3.9 +/- 6.4o • Female – 2.6 +/- 5.1o • + ve angle indicates convex face • -ve angle indicates concave face www.indiandentalacademy.com
Constructions of N-A-PG This angle is formed by the line N-A and A-Pg
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N-A (LINEAR) • Here apical base of maxilla is related to N. • Used to determine if anterior part of maxilla is protrusive/retrusive. • Male – 0.0 +/- 3.7 • Female - -2 +/- 3.7 • +ve indicates prognathism • -ve indicates retrognathism www.indiandentalacademy.com
N-B(LINEAR) • Here apical base of mandible is related to N. • Male - -5.3 +/- 6.7 • Female - -6.9 +/- 4.3 • This quantitates the AP position of mandible and degree of mandibular horizontal dysplasia www.indiandentalacademy.com
N-PG(LINEAR) • This indicates prominence of chin • Used to determine discrepancy in alveolar process, chin or mandibular proper • Also determines the discrepancy in genials • Male - -4.3 +/- 8.5 • Female - -6.5 +/- 5.1 www.indiandentalacademy.com
VERTICAL SKELETAL ANALYSIS • In this analysis all measurements are made perpendicular to HP. • Reflects the anterior, posterior or complex dysplasia of face. N-ANS(Linear) ANS-GN(Linear) PNS-N(Linear) MP-HP(Angle) www.indiandentalacademy.com
N-ANS(LINEAR) • It signifies the middle third facial height. • Male – 54.7 +/- 3.2 • Female – 50 +/- 2.4
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Measurements of N-ANS
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ANS-GN(LINEAR)
• It signifies the lower third facial height. • Male – 68.6 +/- 3.8 • Female – 61.3 +/- 3.3
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Measurements of ANS-GN
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PNS-N(LINEAR) • It signifies the posterior maxillary height • Male – 53.9 +/- 1.7 • Female – 50.6 +/- 2.2
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Measurements of PNS-N
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MP-HP(ANGLE) • It signifies the posterior divergence of mandible shown by MP angle. • The angle relates the posterior facial divergence with respect to anterior facial height • Male - 23o +/- 5.9o • Female – 24.2o +/- 5o
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Construction of MP-HP
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VERTICAL DENTAL ANALYSIS • Measurements for this analysis UI perpendicular to NF LI perpendicular to MP U6 perpendicular to NF L6 perpendicular to MP
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UI TO NF • •
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It denotes the anterior maxillary dental height. Aids to evaluate the total vertical dimensions of premaxilla from approximate piriform aperture perpendicular to tip of maxillary incisor crown. Signifance: indicates how far the incisor have erupted in relation to nasal floor. Male - 30.5 +/- 2.1 Female – 27.5 +/- 1.7
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LI TO MP • This measures the anterior mandibular dental height. • Determines the total dmensions of anterior mandible from MP perpendicular to tip of mandibular incisor crown. • Signifance: denotes how far the incisor have erupted in relation to MP • Male - 45 +/- 2.1 • Female – 40.8 +/- 1.8 www.indiandentalacademy.com
U6 TO NF • This measures the posterior maxillary dental height. • Aids to evaluate the posterior dental mandibular vertical height/molar eruption • Male - 26.2 +/- 2 • Female – 23 +/- 1.3 www.indiandentalacademy.com
L6 TO MP • Measures the posterior mandibular dental height • Male - 35.8 +/- 2.6 • Female – 32.1 +/- 1.9
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MAXILLA AND MANDIBLE ANALYSIS • This is analysed by following measures PNS – ANS AR – GO GO - PG AR-GO-GN B - PG
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PNS-ANS MEASUREMENTS • Denotes the total effective length of maxilla. • Male - 57.7 +/- 2.5 • Female – 52.6 +/- 3.5
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Measurements of PNS-ANS
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Ar-Go linear) • Quantitates the length of mandibular ramus • Male - 52 +/- 4.2 • Female – 46.8 +/- 2.5
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GO-PG(LINEAR) • Aids in establishing the length of mandibular body • Male – 83.7 +/- 4.6 • Female – 74.3 +/- 5.8
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B-PG • This measurements denotes prominence of chin related to mandibular denture base • Male - 8.9 +/- 1.7 • Female – 7.2 +/- 1.9
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AR-GO-GN(ANGLE)
• This angle denotes relationship between ramal plane and MP. • Aids in diagnosis of skeletal open/closed bite problems. • Male – 119.1o +/- 6.5o Female – 122o +/- 6.9o
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DENTAL ANALYSIS Measurements for this analysis • OP – HP (Angle) • A – B(Linear) • U6 – NF(Angle) • L1 – MP(Angle)
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OP-HP(ANGLE) • OP denotes its steepeness/flatness • Increased angle: assess skeletal open bite, lip incompetence,increased facial height, retrognathia. • Decreased angle: assess deep bite, decreased facial height, lip redundancy. • Male - 6.2o+/- 5.1o • Female – 7.1o+/-2.5o www.indiandentalacademy.com
IN CASE OF ANTERIOR OPEN BITE
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Measurements of OP-HP ANGLE
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A-B(LINEAR) • This linear measurements represents the relationship of maxillary and mandibular apical base to OP • Male - -1.1 +/- 2 • Female - -0.4 +/- 2.5 • Significance: if A-B distance is large with point B projected posteriorly to point A denotes class II occlusion and vice versa www.indiandentalacademy.com
U1 – NF(ANGLE) • Represents angulations of maxillary central incisors to NF • Male - 111o +/- 4.7o • Female – 112o +/- 5.3o • Signifance: aids to determine the procumbency/recumbency of incisor • Vitals in assessing long term stability pf dentition www.indiandentalacademy.com
LI – MP(ANGLE) • Denotes angulation of mandibular incisors to MP • Male - 95.9o+/- 5.2o • Female – 95.9o+/-5.7o • Significance: determines the procumbency/recumbency of lower incisor.
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BURSTONE ANALYSIS SOFT TISSUE ANALYSIS
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TRACINGS AND LANDMARK
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Locating soft tissue gnathion ( point of intersection between Sn-Pg and C-Me)
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FACIAL FORMS ANALYSIS This analysis describes overall horizontal soft tissue profile. The following analysis is used: Facial convexity angle(G-Sn-Pg) Maxillary prognathism(G-Sn) Mandibular prognathism(G-Pg) Vertical height ratio(G-Sn/Sn-Me) Lower face throat angle(Sn-Gn-C) Lower vertical height depth ratio(Sn-Gn/C-Gn) www.indiandentalacademy.com
FACIAL CONTOUR ANGLE
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FACIAL CONTOUR ANGLE
INFERENCE • Mean value 12o +/- 4o • +ve value indicates a convex profile • -ve value indicates concave profile
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MAXILLARY PROGNATHISM(G-Sn) • Describes the amount of maxillary excess/deficiency in AP • +ve - maxillary retrusion • -ve - maxillary procumbency • Mean value 6+/-3 www.indiandentalacademy.com
MANDIBULAR PROGNATHISM(G-Pg) • Mean value 0 +/- 4 Inference : • Indicates mandibular prognathism/ retrognathism • Increase –ve value indicates mandibular deficiency
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VERTICAL HEIGHT RATIO • Mean value 1:1 (G-Sn To Sn-Me) Inference • Ratio <1 denotes that disproportionality and there is large lower 3rd face height and viceversa
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Measurement of vertical height ratio
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Lower face throat Angle(Sn-Gn-C) • Mean value 100o +/- 7o • Inference:
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Lower vertical height ratio depth ratio â&#x20AC;˘ Mean value 1.2:1 Inference â&#x20AC;˘ Ratio>1 indicates short neck
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LIP POSITION AND FORM ANALYSIS The following analysis is used • • • • • • •
Nasolabial angle(Cm-Sn-Ls) Upper lip protrution(Ls to Sn-Pg) Lower lip position(Li to Sn-PG) Mento labial sulcus(Si to Li-Pg) Vertical lip chin ratio(Sn-Stms/Stmi-Me) Maxillary incisor exposure(Stm-U1) Interlabial gap(Stms-Stmi) www.indiandentalacademy.com
Nasolabial angle (Cm-Sn-Ls) â&#x20AC;˘ Mean value 102o +/- 8o Inference â&#x20AC;˘ obtuse angle indicates maxillary hypoplasia and viceversa
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Upper lip position(Ls to Sn-pg) â&#x20AC;˘ Mean value 3 +/- 1 Inference â&#x20AC;˘ Increased value indicates protrusion and vice-versa
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Lower lip position(Li to Sn-Pg) •Mean value 2 +/- 1 Inference •Denotes amount of lip protrusion
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Mento labial sulcus(Si to Li-Pg) â&#x20AC;˘Mean value 4 +/- 2 Inference â&#x20AC;˘Assess prominence of the chin
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Vertical lip : Chin ratio (Sn-Stms /Stmi-Me) â&#x20AC;˘ Aids to assess the lower 3rd face. â&#x20AC;˘ Lower 3rd face is divided into 3 parts: length of upper lip i.e distance from SnStms shoule be approximately 1/3rd the total and distance from stmi to Me should be 2/3rd. www.indiandentalacademy.com
Measurements of vertical lip:chin ratio Measurement of sn to stms
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Measurement of Stmi to Me
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Maxillary incisor exposure (Stms-U1) • Distance from upper lip to maxillary incisor is the key factor in determining vertical position of maxilla. • This corresponds to pleasing smile. • 2mm of incisor exposure at rest is normal • Inference: pt. with vertical maxillary excess tend to show a larger amount of upper incisor with lips in repose. www.indiandentalacademy.com
Measurements of maxillary incisor expsoure(Stms-U1)
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Interlabial gap(Stms-Stmi) • Mean value – 2+/-2 • Aids to measure the vertical distance between upper lip and lower lip with lips at rest. • Inference: patient with vertical maxillary excess have increased interlabial gap and lip incompetence and vice-versa
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OTHER PARAMETERS (HARD TISSUE)
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SNA • Mean value – 82+/2 • Inference – increase denotes prognathism and vice-versa
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SNB • Mean value – 78+/-2 • Inference – increased value indicates prognathism and vice versa
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ANB
â&#x20AC;˘ Denotes the relative position of maxilla and mandible.
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FACIAL AXIS ANGLE • Aids locate chin vertically and AP, Locate the mandible –AP and relate effective length of maxilla and mandible • Mean value – 90o+/3o • Lesser angle indicates recessive chin and vice-versa www.indiandentalacademy.com
CHIN POSITION
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Interincisal angle • Denotes the inclination of central incisors • Mean value – 130o +/- 6o
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Lesser angle denotes incisor protrusion greater
angle denotes deep bites
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GRUMMONS ANALYSIS
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OTHER PARAMETERS (SOFT TISSUE)
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GLABELLA PERPENDICULAR TO THE LABIAL SURFACE OF THE UPPER INCISOR
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Construction of subnasale vertical(SnV)
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Upper lip position • Mean value – 1-2mm ahead of SnV • Inference – increase value denotes lip procubency and viceversa
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Lower lip position
• Mean value – 1mm posterior to SnV
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Chin pogonion
â&#x20AC;˘ Normally chin pogonion positioned 1-4mm posterior to Pg
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Construction of zero meridian
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Pogonion position • Mean – 0 +/- 2 to zero meridian. • Inference : variation indicate retrusion/protrusion in mandible and maxilla separately.
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Subnasale position • Subnasale perpendicular to upper lip – normal is 0+/-2mm. • Subnasale perpendicular to lower lip – normal is 2+/2mm • Subnasale perpendicular to chin –normal is 4+/- -2mm www.indiandentalacademy.com
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