Cephalometrics in orthodontics /certified fixed orthodontic courses by Indian dental academy
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Cephalometrics in orthodontics /certified fixed orthodontic courses by Indian dental academy
Cephalometrics in Orthodontics INDIAN DENTAL ACADEMY www.indiandentalacademy.com
CEPHALOMETRICSCephalometric radiography:- is the production of skullradiographs ,which are useful in making measurementsof the cranium and oro-facial complex.PACINI- IN 1922 DEMONSTRATED THE BASIC PROCEDUREOF CEPHALOMETRICS. It was in 1931, HOFRATH in GERMANY and BROADBENT in UNITED STATES published articles in which they had refined the technique and applied these principles to orthodontics.
Cephalostat 60" 60" 15" 15" Film Plane Film Plane Source Plane Source PlaneX-ray Source X-ray Source Mid-saggital X-ray Film in X-ray Film in Mid-saggital Cassette Plane Plane Cassette Patient in Head Patient in Head Positioning Device Positioning Device
Purpose of Cephalometrics•Study craniofacial growth•Diagnosis•Planning orthodontic treatment•Evaluation of treated cases Cephalometrics is a technique employing oriented radiographs for the purpose of making head measurements.
Purpose ofCephalometrics Study craniofacial growth Diagnosis Planning orthodontic treatment Evaluation of treated cases Cephalometrics is a technique employing oriented radiographs for the purpose of making head measurements. www.indiandentalacademy.com
Cephalostat 60" 60" 15" 15" Film Plane Film Plane Source Plane Source PlaneX-ray Source X-ray Source X-ray Film in X-ray Film in Mid-saggital Plane Mid-saggital Plane Cassette Cassette Patient in Head Positioning Patient in Head Positioning Device Device www.indiandentalacademy.com
Cephalometric Values forSelected Groups White Black Israeli Chinese Japanese SNA 82 85 82 82 81 SNB 80 81 78 79 77 ANB 2 4 4 3 4 U1-NA 4 mm, 22 7 mm, 23 5 mm, 24 5 mm, 24 6 mm, 24 L1-NB 4 mm, 25 10 mm, 34 6 mm, 29 6 mm, 27 8 mm, 31 U1-L1 131 119 124 126 120GoGn-SN 32 32 35 32 34L1-MnPl 93 100 93 93 96 L1-FH 62 51 57 57 57 Y axis 61 63 61 61 62 from Proffit,Contemporary Orthodontics, 1992
What Are We Trying toAccomplish? Find out skeletal classification anteroposterior vertical Find out angulation of incisors Consider soft tissue facial profile airway considerations
What Are We Trying toAccomplish? (In other words) Is the patient Class I, II, III skeletal? Does the patient have a skeletal open bite growth pattern, or a deep bite growth pattern, or a normal growth pattern? Are the maxillary/mandibular incisors proclined, retroclined or normal? Is the facial profile protrusive, retrusive, or straight; can the patient breathe normally? www.indiandentalacademy.com
USES OF CEPHALOMETRICS1. It gives a 2 dimensional viewof a three dimensionalobject.2. Reliability ofcephalometrics is not alwaysaccurate,as there can be errors inidentifying the landmarks ortracing etc.www.indiandentalacademy.com
CEPHALOMETRICSDEFINITIONScientific study of the measurement ofthe head.CEPHALOMETRIC RADIOGRAPHYis a standardized method of productionof skull radiographs,which are useful inmaking measurements of the cranium andthe orofacial complex.The radiograph thusobtained is called a cephalogram.
DISCOVERED BY-IN 1931,HOFRATH IN GERMANYAND BOARDBENT IN U.S.AProvided a standardizedcephalometric technique using a highpower x-ray machine and a headholder called a CEPHALOSTAT. www.indiandentalacademy.com
WHY CEPHALOMETRICS?Aids in orthodontic diagnosis by enablingthe study of skeletal,dental and soft tissuestructures of the craniofacial region.Aids in establishing the facial type.Helps in the classification of skeletal anddental abnormalities.Helps in treatment planning.
Aids in evaluating the treatment resultsand recognizing changes brought aboutby treatment.Aids in predicting growth changes andchanges associated with surgicaltreatment.Study of relapse in orthodontics.Valuable aid in research work. www.indiandentalacademy.com
OBTAINING ACEPHALOGRAMCEPHALOMETRIC EQUIPMENTCEPHALOSTAT,X-RAY SOURCE & ACASETTE HOLDER.Cephalostat-2 ear rods-prevent movementof the head in the horizontal plane.Vertical stabilization of the head-orbitalpointer that contacts the lower border ofthe left orbit. www.indiandentalacademy.com
The upper part of the face is supportedwith the help of a forehead clamp which ispositioned above the region of the nasalbridge.The distance between the x-ray sourceand the midsagittal plane of the patient is5 feet.
CEPHALOMETRICLANDMARKSLANDMARK-Is a point serving as a guide formeasurement.An ideal landmark is locatedreliably on the skull and behaves consistentlyduring growth.It should not be assumed that all the landmarksare equally reliable and valid.The reliability,reproducibility and dependability ofa landmark is affected by- www.indiandentalacademy.com
#The quality of the cephalogram.#The experience of the tracer.#Confusion with other landmarks.The cephalometric landmarks should have the following attributes-A) Should be easily seen on the radiograph.B)Uniform in outline.
C)Should be easily reproducible.D)Landmarks should permit validquantitative and qualitative measurementsof lines and angles projected from them.E)Measurements should be amenable tostatistical analysis. www.indiandentalacademy.com
ANATOMIC LANDMARKSThey represent actual anatomic structureson the skull e.g. ANS,NaDERIVED LANDMARKSThese are obtained secondarily fromanatomic structures in acephalogram.e.g.Ar(Articulare),Ptm(Pterygomaxillary fissure) www.indiandentalacademy.com
IMPLANTSThey are artificially inserted radio opaquemarkers, usually made of inert metal.They are ‘PRIVATE POINTS’ and theirposition can vary from subject to subject.They are ideal for longitudinal studies onthe same subject.
UNILATERAL LANDMARKS NASION-The most anterior point midway between the frontal and the nasal bones in the frontonasal suture.
ANTERIOR NASAL SPINE/ANS It is the tip of the sharp bony process of the maxilla in the midline. www.indiandentalacademy.com
PROSTHION The lowest and the most anterior point on the alveolar process in the median plane between the central incisors.
SUBSPINALE/POINT A It is the deepest point in the midline between the ANS and the alveolar crest, between the two central incisors. It is also called as subspinale. Pink dot-pt.A
INFRADENTALE/(Id)The highest and the most anterior point inthe alveolar bone in the midline betweenthe lower central incisors. Blue dot-(Id)
SUPRAMENTALE/Pt.B It is the deepest point in the midline between the alveolar crest and the mental process. Pink dot-pt.B
POGONION(Pog) It is the most anterior point of the bony chin in the median plane. Red dot-(Pog)
MENTON(Me) It is the most inferior midline point on the mandibular symphysis. Yellow dot-Me
GNATHION(Gn) It is the most antero -inferior point on the symphysis of the chin. It is constructed by intersecting a line drawn perpendicular to the line connecting menton and pogonion. Orange dot-(Gn)
BASION(Ba) It is the median point on the anterior margin of foramen magnum.
POSTERIOR NASALSPINE(PNS) The most posterior point in the bony hard palate in the sagittal plane. Marks the distal limit of the maxilla.
SELLA(S) The point representing the midpoint of sella tursica. www.indiandentalacademy.com
GLABELLA:It is the most prominent point of the forehead in the mid-saggital plane. SUBNASALE:The point where the lowest border of the nose meets the outer contour of the upper lip. ●G ●Snwww.indiandentalacademy.com
BILATERAL LANDMARKS1)ORBITALE(Or)The lowest point on the inferior bonymargin of the orbit. www.indiandentalacademy.com
G0NION It is a constructed point at the junction of ramal plane and mandibular plane. www.indiandentalacademy.com
CONDYLION/(Co) The most superior point on the head of condyle.
ARTICULARE/(Ar) It is a point at the junction of the posterior border of the ramus and inferior border of the basal part of the occipital bone. Blue dot-(Ar)
PTERYGOMAXILLARYPOINT/PtmIt is the intersection of the inferior borderof foramen rotundum with the posteriorwall of pterygomaxillary fissure.It is a bilateral tear drop shaped area ofradiolucency. www.indiandentalacademy.com
PORION/(Po) The highest bony point on the upper margin of the external auditory meatus. www.indiandentalacademy.com
BOLTON POINT The highest point at the posterior condylar notch of the occipital bone. Bo www.indiandentalacademy.com
THE KEY RIDGE-The lowest most pointon the contour of the anterior wall of theinfratemporal fossa.CHELION:It is the lateral terminus of theoral slit on the outer corner of the mouth. www.indiandentalacademy.com
LINES AND PLANES INCEPHALOMETRYCephalometrics makes use of certain linesor planes. These lines are obtained fromconnecting two landmarks.Based on their orientation the lines orplanes are classified into:Horizontal and vertical planes.
HORIZONTAL PLANES1)S.N.PLANE- It is the cranial linebetween the center of sella tursica and theanterior point of the fronto nasalsuture(nasion).It represents the anterior cranial base.
FRANKFORT HORIZONTALPLANE This plane connects the lowest point of the orbit(orbitale)and the superior point of the external auditary meatus(porion). www.indiandentalacademy.com
OCCLUSAL PLANE It is a denture plane bisecting the posterior occlusion of the permanent molars and premolars(or deciduous molars in mixed dentition)and extends anteriorly.
MANDIBULAR PLANESeveral mandbiular planes are used incephalometrics,based on the analysisbeing done. The most commonly usedones are-TWEEDS-Tangent to the lower border ofthe mandible.STEINERS-A line connecting gonion andgnathion.DOWNS-A line connecting gonion and
PALATAL PLANE It is a line linking the anterior nasal spine of the maxilla and the posterior nasal spine of the palatine bone.
BASION-NASION PLANE Line connecting the basion and nasion. Represents the cranial base.
VERTICAL PLANE A-POG LINE: It is a line from point A on the maxilla to pogonion on the mandible.
FACIAL PLANE It is a line from the anterior point of the frontonasal suture (nasion)to the most anterior point of the mandible(pogonion).
BOLTON’S PLANE This is a plane that connects the Boltons points posterior to the occipital condyles and nasion. Bo www.indiandentalacademy.com
FACIAL AXIS It is point from Ptm point to cephalometric gnathion.
ESTHETIC PLANE/E PLANEIs a line between the most anterior point ofthe soft tissue nose and the soft tissuechin. www.indiandentalacademy.com
FRONTAL CEPHALOGRAM (P-A VIEW) This provides an antero-posterior view of the skull.www.indiandentalacademy.com
The goal of lateral ceph Analysis is to establish the Antero-posterior and Vertical relationships of the Five major cranio-facial units. 1.The cranium and cranial base 2.The naso-maxillary complex 3.The Mandible 4.The Maxillary dentitionwww.indiandentalacademy.com Mandibular dentition. 5.The
STEINERS ANALYSISSteiner’s analysis is divided into 3 parts:-1. Skeletal Analysis2. Dental Analysis3. Soft tissue analysis www.indiandentalacademy.com
Soft Tissue Analysis‘S-LINE’ : According to Steiner the lips in a well balanced facesShould touch a line extending from the soft tissue contour of theChin to the middle of the ‘S’ formed by the lower border of theNose.THIS LINE IS REFERRED TO AS THE ‘S’ LINE. www.indiandentalacademy.com
DOWN’S ANALYSIS -1952DOWN’S :-Study based on 20 Caucasian subjects ,rangedIn age from 12 to 17 years of age and were equally dividedAs to sex.All the individuals possessed clinically excellent occlusions. www.indiandentalacademy.com
DOWN –divided his analysis into 2 components----1. The skeletal component helped in defining the underlying facial type .2. The dental component is used to establish if the dentition is placed normally in relation to the underlying bony structures. www.indiandentalacademy.com
DOWN’S POLYGON The graph divided into:- 1.Skeletal pattern on the top half of the graph 2.Denture polygon on the lower half of the graph.Wigglegram:- helps us inVisualizing the type ofmalocclusion I.e, Skeletalor dental..
A functional occlusal plane is drawn through theoverlappingCusps of first pre-molars and first molars.Perpendiculars are drawn to the occlusal planefrom pointsA and B .The points of contact of these perpendiculars onthe occlusalPlane are termed AO and BO.The distance between points AO and BO gives theantero-Posterior relation between the two jaws,. www.indiandentalacademy.com
TWEED- developed this analysis as an aid to:•Anchorage preparation•To treatment planning•And determining the prognosis of orthodontic cases Tweed’s analysis is based primarily on the deflection of the mandible as measured by the Frankfurt Mandibular plane Angle(FMA) and the posture of the lower incisor. It is done to determine the final position the lower incisor Should occupy at the end of the treatment. Dr.Tweed established that prognosis could be predicted relatively accurately based on the configuration of the triangle
Tweeds triangle is formed by:1. Frankfurt horizontal plane2. The mandibular plane3. The long axis of lower incisor.s The three angle’s formed are: • Frankfort-Mandibular Plane(FMA) Angle---- • FH Plane with mandibular plane. • Lower Incisor to Mandibular plane(IMPA)Angle----- • Long axis of lower incisor with mandibular plane. • Frankfort Mandibular Incisor Angle (FMIA)-------- • Long axis of lower incisor with FH plane. FMA=25degrees IMPA=90degrees FMIA=65degrees.
Based on the FMA angle the prognosis can be predicted:-1. FMA 16 to 28 degrees- prognosis good Apprx. 60% of malocclusions have FMA between 16 to 282.FMA from 28 to 35 degrees prognosis fair. Extractions necessary in majority of cases3.FMA above 35 degrees , prognosis bad ,,extractions frequently complicate the problem. www.indiandentalacademy.com