Lat Ceph

Question 1

Cephalometrics Definition

Answer 1

Standardised radiographic procedure for analysing the complexities of the live human head with a geometric measurement.
A cephalometric tracing comprises soft and hard tissue outlines and anatomic landmarks and points

Question 2

Why Lat Ceph for Ortho

Answer 2

High % of severe malocclusions is associated with discrepancies in jaw relationships

Question 3

Cephalometric analysis

Answer 3

• Collection of measurements derived from the cephalogram suitable for diagnosis and treatment planning/evaluation
• Has both angular and linear measurements
• Compared to norms

Question 4

Standardisation for Lat Cephs

Answer 4

Distance from mid saggital plane to casette is the same for each patient

Question 5

Indications for Lat Cephs

Answer 5

• Marked AP discrepancy: Class II, Class III
• Class I bimax protrusion
• Marked Vertical Discrepancy: AOB, Deep overbites

Question 6

Cranial base landmarks

Answer 6

Sella - geometric centre of the sella turnica
Nasion - most anterior portion of the fronto-nasal suture
Basion - Most inferior tip of the clivus/Most anterior part of the foramen magnum
Porion - Most superior point of the external auditory meatus
Orbitale - Most inferior point of the lateral orbital margin

Question 7

Maxillary landmarks

Answer 7

Anterior Nasal Spine - Most prominent point on the anterior maxilla in the mid-saggital plane
A-point - Deepest point in the concavity of the anterior maxilla in the mid saggital plane
Posterior Nasal Spine - Distal most point on the hard palate in the mid-saggital plane

Question 8

Mandibular landmarks

Answer 8

Gonion - The midpoint of the mandibular angle between the mandibular ramus and corpus
Menton - The extreme inferior point of the mandibular symphysis
Pogonian - The extreme anterior point of the mandibular symphysis
B-point - Deepest point on the curvature of the mandibular alveolar process

Question 9

Ceph Planes

Answer 9

Anterior cranial base - Sella Nasion (SN)
Frankfort Horizontal (FH) - Po-Or
Maxillary Plane (MxP) - ANS-PNS
Functional Occlusal Plane (FOP)
Mandibular Plane (MdP) - Go-Me

Question 10

A-P Jaw Relationships

Answer 10

SNA - angle measuring the r/s of the maxilla to the cranial base
SNB - angle measuring the r/s of the mandible to the cranial base
ANB - angle measuring the relative position of the maxilla to the mandible (Skeletal base r/s) - WRT N point
Wits value - relative position of the maxilla to the mandible - WRT occlusal plane

Question 11

Vertical Jaw Relationships

Answer 11

Frankfort-Mandibular plane angle (FMA)
Maxillary-Mandibular plane angle (MMA)
Posterior Facial Height: S-Go (60-66% of TFH)
Upper Anterior Facial Height: N-ANS
Lower Anterior Facial Height: ANS-Me (50-55% of TFH - should relate to MMA value)
Total Anterior Facial Height: N-Me

Question 12

Dental Analysis

Answer 12

Inter-incisal angle: U1-L1

Question 13

Profile Analysis

Answer 13

Rickett’s E-line: On soft tissue, from tip of nose to prominent point on chin
Used for checking lower lip protrustion - R/S of lower lip to E-line (Chinese is protruded)