Cephalometrics as a Diagnostic Aid / orthodontic courses by Indian dental academy

CEPHALOMETRICSAS A DIAGNOSTIC AID  Introduction  Definition  Types of cephao!ra"  #ses  Anato"ic and"ar$s  Lines and panes of atera cephao"etrics  Cephaostat  Steiner anaysis  Do%ns anaysis  T%eed&s anaysis  'its appraisa  Sassouni anaysis  McNa"ara anaysis  Ric$etts anaysis 1 INTROD#CTION ‘Beauty is the finest expression of human emotion. The art that was produced in the past has survived because it was expressed in the highest, finest and most sensitive manner possible. The beauty that survives knows no limits either of time or place’. ( 'uerpe Ever since God created man in his image, man has been trying to change man into his image. Orthodontists, in their attempts to treatment planning with brought various analysis into being. In )*++, Pacini introduced a method for standardized head radiography and failed due to large fixed distance from !ray source to the cassette. Dr- Her.ert Hofrath of Germany and Dr- /- Hoy /road.ent of ".#. published a new !ray techni$ue and its application in orthodontia. In )*01, Dr- Chares T%eed developed T%eeds dia!nostic trian!e. %irst true classic full scale cephalometric analysis developed by 'iia" /- Do%ns in )*02. In )*34, Dr- C-C- Steiner presented his famous Steiner&s anaysis. Riede in )*3+ developed SNA and SN/ angle. Sassouni 5)**36 described total archia anaysis. Ric$ets 5)*176 give dynamic analysis to study morphology of a patient at different stages of development or treatment. 8aco.son&s 9'its& appraisa 5)*:36 was used for assessing horizontal disharmony of the &aw. %or surgical correction ;uadriatera anaysis Dipaoo 5)*:76 and an analysis by McNa"ara 5)*206 developed. ' DE<INITION (ephalometrics includes measurements, description and appraisal of the morphologic configuration and growth changes in the s)ull by ascertaining the dimensions of lines, angles and planes between anthropometric landmar)s established by physical anthropologists and point selected by orthodontists. T=PES O< CEPHALOGRAM 1* +ateral cephalogram '* %rontal cephalogram #SES 1* ,elps in orthodontic diagnosis, by enabling study of s)eletal, dental and soft tissue structures of the craniofacial region. '* ,elps in classification of malocclusion. -* ,elps in treatment planning. .* Evaluation of treatment results. /* ,elps in predicting growth related change. 0* It is also valuable aid in research wor). ANATOMIC LANDMAR>S 1* Nasion 1 2ost anterior patient on naso frontal suture. '* Sea 1 2idpoint of hypophyseal fossa. -* Si 1 2ost inferior patient of lower contour of sella turcica. .* SP 1 2ost posterior patient on posterior contour of sella turcica. /* Se 1 2idpoint of the entrance of sella. 3t the same level of &ugum sphenoidal. - 0* Point A 4su.spinae6 1 5eepest midline patient in the curved bony outline from the base of alveolar proceeds of the maxilla. i.e. between 36# and 7rosthion. Dono?an ( 8unction of maxillary basal bone and alveolar bone. Hi!ey 1 5eepest midline point between 36# and 7rosthion on the premaxilla. 8aco.son 1 3nterior limit of maxillary denture base. 9* Prosthion 1 3lveolar rim of maxilla or the lower most anterior point on the alveolar portion of the premaxilla in the median plane between upper central incisors. :* Is 5Incisor spurious6 1 ;ip of crown of most anterior maxillary central incisor. <* AP ) 5Apicae )6 ! =oot apex of the most anterior mandibular central incisor. 1>* Ii 5Incisor inferius6 ! ;ip of crown of most anterior mandibular incisor. 11* AP ) 1 =oot apex of most anterior maxillary incisor. 1'* Intradenta 1 3lveolar rim of mandibular. 1-* Point / 5Supra"entae6 1 2ost anterior part of mandibular base or it is the most posterior point in the outer contour of the mandibular alveolar process, in the median plane. Dono?an 1 8unction of mandibular basal bone and alveolar process. 8aco.son 1 3nterior limit of mandible 1.* Po! ! 2ost anterior point on bony chin in median plane. 1/* Gn /rodie 1 +ocated by ta)ing the midpoint between most anterior and inferior points on the bony chin. Crai! 1 7atient of intersection of facial and mandibular plane. . 10* Go 1 (onstructed point at the intersect of lines tangent to posterior margin of ascending ramus and mandibular base. Hin!ey 1 Intersection of posterior ramal and mandibular plane. 19* Me 1 Sassouni ! 2ost caudal point in the outline of the symphysis or the inferior most point on mandible. 1:* Ar 5Articuare6 ! /@or$ 1 7oint of intersection of the posterior margin of ascending ramus and outer margin of cranial base. 1<* Cd 5Condyion6 1 2ost superior point on the head of the condyle. '>* Or 5Or.itae6 1 +ower most point of the orbit in radiograph. '1* ANS 1 ;ip of bony anterior nasal spine in the median plane. ''* PNS 1 ;he intersection of continuation of anterior wall of pterygopalatine fossa and the floor of nose. '-* /asion 1 +owest point on the anterior margin of foramen magnum in the median plane. '.* Pt" 5Ptery!o"aAiary fissure6 1 3nterior wall represents maxillary tuberosity outline, posterior wall represents anterior curve of pterygoid process. '/* Po 5Porion6 1 T%eed 1 ../mm above geometric center of ear rod. Crai! 1 "ppermost point on the soft tissues overlying the external auditory meatus. Ric$etts 1 ;rue 7orion, located directly over that of basion and downward and forward from internal auditory canal. Moorrees 1 (enter of ear rods. Hi!ey 1 ,ighest point on the root of the left external auditory meatus. / '0* /O 5/oton point6 1 /road.ent 1 ,ighest point in the upward curvature of the retrocondylar fossa. Hi!ey 1 ,ighest point in the concavity behind the occipital bone. '9* D point 1 (enter of symphysis given by #teiner. ':* Op 5Opisthion6 1 2ost posterior point of the bony margin of the foramen magnum. '<* AC 5Acanthion6 1 ;ip of 36#. ->* 8 point 1 +ocated at the &unction of the anterior border of ramus and the corpus of mandible. -1* DS 5Dorsa" seae6 1 #$uare bone forms posterior boundary of sella turcica. -'* /road.ent re!istration patient 5R6 1 7erpendicular from sella on 6asion 1 ?olton plane. 0 LINES AND PLANES O< LATERAL CEPHALOMETRICS 1* /u"en.ach&s pane 5Restin! horiBonta pane6 ! It is the plane formed as the s)ull, minus the mandible rest on a flat horizontal surface. Entails the s)ull resting anterior on maxillary teeth and posterior either on occipital condyles or on the mastoid process. '* /road.ent&s ine 5S(N reference ine6 1 %rom sella to nasion. -* /road.ent /oton ine 1 +ine from ?olton patient to nasion. .* /roca&s ine 1 Extends from true anatomic prosthion to the lower most point of the occipital condyle. @hen s)ull is resting on horizontal surface. /* Ca"per&s ine 1 +ine extending from tip of 36# to the centre of external auditory meatus. (amperAs plane is a triangular plane formed by two lines from tip of 36# to each external auditory meatus. 0* Decoster&s ine 1 ;his is the only line that is not linear connection of two points. It represents an actual anatomical contour of the planoethmoidal line from internal plate of frontal bone down through roof of cribriform plate to the anterior portion of sella turcica. 9* <ran$fort horiBonta pane6 1 Its origins date bac) to the international congress on prehistoric anthropology and archaeology, held in <ran$fort in )22+. ;he line runs from orbitale to porion. It is supposed to represent the ideal horizontal position of the head when the patient stands erect. :* Paata pane 1 +ine running from 36# to 76#. <* His pane 1 =uns from acanthion to opisthion. 1>* Hod %ay ine 1 3lso referred as harmony line was developed by R-A- Hoda%ay and is strictly a soft tissue profile assessment 9 reference line. =uns from soft tissue pogonion to vermilion border of upper lip. 11* HuAey&s ine 1 =uns from nasion to basion and referred as nasion C .asion ine. It would be the near perfect base reference line for research purposes on growth and development. 1'* Mandi.uar pane 1 %our different mandibular planes. Steiner 1 +ine &oining Go and Gn Do%ns 1 +ine &oining Go and 2e T%eed and Ric$etts 1 #traight line tangent to the lower most border of mandible. /i"per&s ine 1 +ine from menton to antigonial notch. 1-* Mar!ois ine 1 +ine runs from nasion to spheno!occipital! synchondrosis. 1.* Occusa pane 1 - occlusal planes. <irst pane 1 +ine &oining midpoint of overlap of 2!? cusps of upper and lower first molars with point bisecting overbite of incisions. "sed by Do%ns and Steiner. Second pane 1 "sed by Ric$etts and in 'its analysis called as functional occlusal plane and is line &oining the midpoint of the overlap of 2!? cusp of I st molars and buccal cusps of premolars or deciduous molars. Third pane 1 +ine &oining midsection of molar cusps to the tip of upper incisors. 1/* Or.ita pane 1 7lane perpendicular to %, plane at orbitale. 10* Ra"a pane 1 +ine tangent to posterior border of ramus of mandibular. 19* Ric$ett&s esthetic ine 1Extends from soft tissue tip of nose to the most anterior portion o profile of soft tissue chin. : 1:* Don Iherin!&s ine 1 Orbitale to center of external auditory meatus. 1<* =(aAis 1 Given by Do%ns and extends from sella to gnathion. CEPHALOSTAT 3n : × 1> inches film cassette e$uipped with approximate film and intensifying screen is placed either horizontally or vertically in the cephalostat cassette holder. 3 distance of 1/ cm from midsagittal plane of the cephalostat to the film cassette is often used. ;he patients head is fixed by two ear!rods that are inserted into ear holes so that upper border of ear holes rest on upper part of ear rods. ;he head is oriented with the %, plane parallel to the floor and midsagittal plane vertical and parallel to the cassette. ;he standardized %, plane is achieved by placing the infra!orbital pointer at the patients orbit and ad&usting the head vertically until the infra!orbital pointer and two ear rods are at same level. ;he upper part of face is supported by forehead clamp positioned at nasion. 7ro&ection is ta)en when teeth are in centric occlusion and the lips relaxed. ;he focus film distance is usually / feet i.e. 1/'..cm. 2illiamperage should be 1>23, BC7 is about 0>!<>Bv and exposure time is not longer than - seconds. STEINER ANAL=SIS 5)*346 C- C- Steiner selected what he considered to be the most meaningful parameters and evolved a composite analysis. ,e proposed a appraisal of s)eletal, dental and soft tissue analysis. ,e considered #6 plane as a reference plane. + 1 7ro&ect the most anterior point of the body of the mandible to the line #6. < E 1 Erect the line from the most distal point of head of condyle, perpendicular to the line #6. S$eeta anaysis 1* #63 angle ! :' > '* #6? angle ! :> > -* 36? angle ! ' > a. (lass! I 1 36? ! >!/ > b. (lass!II 1 36? ! D 0 > c. (lass!III 1 36? ! E > > .* #65 angle ! 90 > /* 2andibular plane to #6 ! -' > 0* Occlusal plane to #6 ! 1../ > Denta anaysis 1* "I to 63 4angle* ! '' > '* "I to 63 4linear* ! .mm -* +I to 6? 4angle* ! '/ > .* +I to 6? 4linear* ! .mm /* Interincisal angle ! 1-> > 0* ,oldaway ratio ! 1F1 #+ ! /1mm #E ! ''mm Steiner anaysis for Indian popuation Sidhu S-S- in )*:7 gave the Indian 42aharashtrian* norms. #ample size was '/ and all were male with the age group of 1-!10 years. 1* #63 ! :'.9 G 9..' '* #6? ! 9<.. G 9.:. 1> -* 36? ! -.- G -.0. .* "I to 63 ! '/ G <..' /* +I to 6? ! -' G 9.'' 0* #+ 4mm* ! /- G 11.9: 9* "I to 63 4mm* ! 0.9 G -.9. :* +I to 6? 4mm* ! 9.0 G '.0: <* %, to #6 ! 0 G /.:0 1>* 5istance of "0 to 63 ! '-.- G './0 11* 5istance of +0 to 6? ! 19.< G '.<0 Ga"" and Gianey in )*:7 gave #.5. to the values of Steiners analysis. Para"eters Mean S-D- #63 :>.0 > -.- #6? 9: > -.1 36? './ > 1.9 #65 9/.' > '.: 7g to 6? './mm 1./mm IHI 1'/.. > 9.< O7 19.- > ..1 27 -'.: > -./ "IH63 /.'mm 1.'mm "IH63 '- > 0.1 +IH6? ..9mm 1./mm +IH6? '9./ > ../ 11 (omparison of Steiners values with Ga"" and Gianey&s value and Maharashtrian nor"s 4Indian* Para"eters Steiner&s ?aues Ga"" E Gianey Maharashtrian nor"s #63 :' > :>.0 > G -.- :'.9 > G 9..' #6? :> > 9: > G -.1 9<.. > G 9.:. 36? ' > './ > G 1.9 -.- > G-.0. #65 90 > 9/.' > G '.: ! 27 -' > -'.: > G -./ ! O7 1../ > 19.- > G ..1 ! "I to 63 '' > '- > G 0.1 '/ > G<..' "I to 63 .mm /.' G 1.'mm 0.9 G -.9.mm +I to 6? '/ > '9./ > G../mm -' G 9.'' +I to 6? .mm ..9 G 1./mm 9.0 G '.0: IHI 1-> > 1'/.. > G9.< ! ,oldaways ratio 1F1 ! ! #+ /1mm ! /- G 11.9: #E ''mm ! ! DO'N ANAL=SIS 5)*026 5owns observed following four basic facial types. 1* Retro!nathic 1 3 recessive lower &aw '* Meso!nathic 1 3n ideal o average lower &aw -* Pro!nathic 1 3 protrusive lower &aw .* True pro!nathis" 1 7ronounced protrusion of lower face. 5owns elected to use %, plane as a reference base from which to determine the degree of retrognathism, prognathism or orthognathism. #ample 1 '> children, 1' to 19 years of age with excellent occlusion with a mean age of 1../ G './ years were ta)en. Measure"ents Ran!e Mean A !keletal measurements 1* %acial angle '* 3ngle of convexity -* 3!? plane angle :' > G<' > 1> > G!:./ > !< > G> :9.: > > > !..0 > 1' .* 2andibular plane angle /* I!axis ': > to 19 > 00 > to /- > '1.< > /<.. > B "ental measurements 1* (ant of occlusal plane '* Interincisal angle -* +I to mandibular plane .* +I to occlusal plane /* 5istance "I to 3! 7og 1./!1. > 1->!1/>./ > !:./!9 > -./ > !'> > !1mm to /mm <.- > 1-/.. > 1.. > 1../ > '.9mm Dorrhies and Ada"s 5)*3)6 made a graphic portryal of 1> values calculated by 5owns. ?ut later on in )*3+ it was modified by 'yie and his polygon shows not only mean but the maximum and minimum range for each measurement. Do%ns anaysis for Maharashtrian ;his study was done by >ota$ D-/- 5)*176 6ot mentioned any sample size. Measure"ents Mean Ran!e 1* %acial angle :..<: > 9<!<1 '* 3ngle of convexity -.9/ !1. to 1- -* 3!? plane angle !..:/ !1> to -./ .* 2andibular plane ''.9- 11!-. 1- /* I!axis 01.:/ /../!0:./ 0* (ant of occlusal plane 11.// >!1: 9* Interincisal angle 11<.0 1>/./!1-../ :* +I to mandibular plane 19.1- /!'< <* +I to occlusal plane '<.'' '1!.1 1>* "I to 3!7og 4mm* 9./ -./!11 T'EED&S ANAL=SIS C )*01 ;weed has focused on how cephalometrics might be applied in diagnosis and treatment planning for daily clinical orthodontics. It consists of a triangle formed by %, plane, mandibular plane and axis of lower incisor. 3 sample of </ was ta)en and average values seen were %273 1 '../9 > I273 1 :0.<- > %2I3 1 0:.'> > ,ence %273 of '. > , I273 of <> > and %2I3 of 0/ > were wor)able figures ad still used. T%eeds pro@ected scae 5<MIA for"ua6 1* @hen %273 is -> > or more 1 %2I3 should be 0/ > or more upto 9> > . '* If %273 is '/ > G. > 1 %2I3 should be 0: > or 9> > . -* If %273 is '> > or less 1 I273 should not exceed <. > . T%eeds head pate correction If %273 ore than '/ > then I273 should not be <> > or more. e.g. If %273 showed ': > , then I273 would have to be positioned at :9 > . ;his is termed as ;weedAs head plate correct. Cephao!ra" correction ;o achieve the %2I3 re$uirements of 0/ > we re$uire tipping of mandibular incisors lingually and will re$uire shortening both the side of dental arch. 1. 3ccording to ;weedAs head plate correction for every ' > correction 1mm of space is re$uired. %or both side of arch it will become 'mm. ;he measurement ta)en from cephalogram combined with actual arch length discrepancy and this is the total discrepancy in millimeters. 'IT APPRAISAL 5)*:36 @its appraisal of &aw disharmony given by 8aco.son is measure of the extent to which the &aws or related to each other anteroposteriorly. 3s a measurement from the cranial base do not necessarily provide are liable expression of 3!7 8aw relationship in the dentofacial complex. =eference plane common is both dentures is that of occlusion, hence the effects of rotation of &aw are not affecting the overall assessment of the &aw. #ample of .0 adults with excellent occlusion were ta)en. 4'1 2 J '/ %* Construction ! 5raw perpendicular from point 3 J ? on the maxilla and mandible on to the occlusal plane. ;he points of contacts of the perpendicular onto the occlusal plane are labeled 3O and ?O respectively. 'its readin! 2ales 1 1 mm %emales 1 > mm ;he more the wits reading deviates from !1 mm in males and > mm in females the greater the horizontal &aw disharmony Cass(II ! 7ositive wits reading Cass(III ! 6egative wits reading If 3O ahead of ?O then wits appraisal positive SASSO#NI ANAL=SIS 5)*336 1/ Sassouni wanted a system based on relationships of anatomical structures to each other with in the frame wor) of the individual patients i.e. he wanted to let the patients own amatory serve as the clue to what is none al of abnormal to himself. ;hus he developed a system that utilizes a series of portions of circles in the form of arcs, that have a common center formed by intersection of composite of anatomical planes to form what has become )nown as the Sassouni archia anaysis. ;his analysis is -!dimensional and inclusive of all the important structures of facial s)eletal. Sa"pe 1 /> children with normal occlusion Point O 1 It is the center of the focal area where the four horizontal planes of the face i.e. cranial base, palatal, occlusal and mandibular converge. Panes 5raw a plane parallel to supraorbital plane tangent to #i. %our planes converge toward focal area called center or point O. Generally - of the . planes meet, while the fourth is divergent. ;his shows the plane, which is not integrated in the facial balance. Occasionally only two planes meet at the same point two others are parallel or meeting in front or beyond point O. In these cases the &unction of the cranial base J mandible planes should be ta)en as the center O. Arcs( %rom O as of center, draw arcs from 6, 36#, 3, ;e J #p. #orms )- Panes 1 %our planes are converging toward a focal center O. +- <acia an!es 1 (ranial base plane to palatal plane angle is e$ual to the palato!mandibular angle. 4- Arcs( 10 a. ;he arc 1 from 6 should pass through 36#, tip of "I, pogonion. If whole lower face is anterior or posterior to the arc from 6, draw a second are from 36# down. ;his should pass through tip of "I and pogonion. b. ;he arc from point 3 down should pass through point ?. c. ;he arc from #p 45orsam #ella* should pass through gonion. d. ;he arc from ;e 4;emporale* should be tangent to the mesial contour of "0. Dertica proportions $ Anterior vertical proportions 7ut the point of compass on 36# J open compass to supraorbitale, then transfer this dimension by rotating the compass until it intersects anterior arc at the menton. 5istance from 36# to supraorbitale should be e$ual to that from 36# to 2e. % &ost vertical proportions %rom 76# to cranial base plane J then from 76# to Go. ?oth distances should be e$ual. Anteroposterior e?auation of profie In normal profile 36#, I#, and 7og should be located on anterior arc It 36# J 7og both posterior to anterior arc then the profile is retroarchial which essentially is normal. ;his situation may be due to the fact that nasion is to far anterior. It 36# is on anterior arc 7og is not there are two possibilities. 1. 7og is anterior to arc '. 7og is post to arc 19 It 7og is on anterior arc J 36# is not, there are also two possibilities 1. 36# is anterior to arc '.36# is posterior to arc 3ny combination of maxillary protrusion andHor mandibular retrusion called as s)eletal (lass II. 3ny combination of maxillary retrusion andHor mandibular protrusion called as s)eletal (lass II. SiBe of corpus of "andi.e It Go located on posterior arc and 7og is on anterior arc then corpus length is e$ual to the cranial base 4#p to 6*. ;his is for 1' year of age. ?efore 1' years corpus of mandibular is small and after 1' year corpus is larger than cranial base. Dertica .aance ;he anterior upper and lower face heights should be e$ual. ;he posterior upper and lower face heights should be e$ual. 36# to cranial base K 36# to mandibular plane and 76# to cranial base K 36# to mandibular plane ;he tip of "I is situated at the midpoint between 36# and 7og. ;he tip of +I is situated at the midpoint between 3 and ?. Interpretation !keletal deep bile cases • . bony planes of face are not steep to each other and center O is away from profile. • (ranial base angle 4supraorbital to clivus angle* is small. 1: • "pper and lower incisors have long axis nearly parallel and are vertically extruded while molars are intruded. • ;otal post height is nearly e$ual to ant facial height !keletal open bile cases • . bony planes are steep to each other bringing the center O close to the profile. • (ranial base angle and genial angle are obtuse. 7%, half the 3%,. !keletal 'lass (( cases • +arge cranial base angle, small gonial angle with short ramus. • 7alate is tipped down word and bac)ward !keletal 'lass ((( cases • #mall cranial base angle • +arge genial angle and palate is tipped upward at 76# and downward at 36#. SASSO#NI PL#S 3fter Sassouni&s death in )*24, a new champion of archial analysis, Dr- Richard /eiste arose to continue wor) of teaching and promoting this great analysis. ?eistle represents 11 points now called as Sassouni plus. 1< ;he first eight components are from original Sassouni, the last three which form the plus form of the last three which form the plus form of the analysis. 1. #)eletal 37 alignment '. #)eletal vertical dimension -. 2axillary incisor position .. 2axillary 37 length /. 2axillary 37 position 0. 2axillary 0 position 9. 2andibular 37 length :. 2andibular 37 position <. 2andibular incisor position 1>.Growth direction indicator 11."pper lip angle )- S$eeta AP en!th It 36# and 7og both post to anterior arc profile is retroarchial It may be due to ! 6 too for anteriorly ! Entire lower face too far posteriorly. ! (ombination of both. If 36# to 7og both anterior to anterior arc profile considered prearchial. It may be due to ! 6 positioned too far posteriorly ! Entire lower face too far anteriorly ! (ombination of both. 3 point and ? point ideally showed be on basal arc. '> +6 S$eeta ?ertica di"ension 3t age . years 3"%, K 3+%, 3t age 1' years 3+%, is more by 0mm and 3t adulthood 3+%, is more by 1>mm 46 MaAiary incisor position ;ip of "I should be on anterior arc or within range of > to - mm ahead of anterior arc. 06 MaAiary AP en!th 5rop cribriform perpendicular on 76# It 76# is on cribriform perpendicular and 36# on anterior arc then maxilla is normal. 36 MaAiary AP position If 36# and 76# both bac) of anterior arc and cr perpendicular by the same amount 1 maxillary retruded. If 36# and 76# ahead of there respective reference line 1 maxilla is protruded. 16 #1 position 2esial surface should be tangent to midfacial arc. :6 Mandi.uar AP en!th 2easured from anterior and posterior arc at Go and 7og. 26 Mandi.uar AP position If Go and 7og displaced in opposite direction an abnormally large mandible or abnormally small mandible is indicated. *6 LI position I273 angle is seen in this. It is </ > ± / > . )76 Gro%th direction indicator '1 ?eistle split the gonial angle and uses the upper and lower portions of it to evaluate growth direction. ;he upper position of split gonial angle represents slant of ramus. +ower portion of angle represents slant of the body of mandibular corpus. ;otal gonial angle 1'>!1-' > "pper gonial ! /'!// > +ower gonial ! 9>!9/ > If upper gonial angle is large and lower is small indicating strong horizontal growth pattern. If upper gonial angle is small and lower is large indicating strong downward and bac)ward grower. ))6 #pper ip an!e (onstructed by drawing a line tangent to anterior most tip of upper lip i.e. soft tissue subnasale and extending it upward to intersect the optic plane, which is parallel to %,. 3ngle is measured inferiorly and posterior at the intersection If <> > or less =etruded <1!<< > %lat 1>>!11/ >! 6ormal 110 or more 7rotruded McNAMARA&S ANAL=SIS 5)*206 ;he analysis proposed by McNa"ara is an effort to relate teeth to teeth, teeth to &aws, each &aw to the other and the &aws to the cranial base. Sa"pe ! '99 children : to 1> years of age with (lass II malocclusion were selected. Effective maxillary length 1 (ondylion to point 3 Effective mandibular length 1 (ondylion to Gn +ower face height 1 36# to 2e '' 3natomic portion is used Measure"ents a* Reatin! "aAia to crania .ase 1 5etermine by measuring distance of point 3 to 6asion perpendicular. b* Reatin! "andi.e to crania .ase 1 5etermined by measuring distance from 7og to 6asion perpendicular. A!e Point A(NP Po! C NP < years >mm !:mm to 10mm 3dult 1mm in front !' to L'mm c6 Reatin! "aAiary and "andi.uar hei!ht < years 3dult male 3dult %emale Effective maxillary length! :/mm 1>>mm <.mm Effective mandibular length! 1>/mm 1->mm 1'>mm +%, ! 0>mm 9>mm 00mm d6 Mandi.uar pane an!e %, to Go 1 2 K '- > +ow mandibular plane angle 1 3de$uate ramus height ,igh mandibular plane angle 1 #hort vertical height e6 Reatin! upper incisors to "aAia ,orizontal position ! 5istance between point 3 perpendicular to the facial surface of upper incisors K . mm Certical position ! Incisal edge of upper incisors lies '!- mm below the upper lip at rest. f6 Reatin! the o%er incisor to "andi.e ,orizontal position '- ! 5istance between 3!7og line and facial surface of lower incisor K ' mm Certical position ! Certical position of lower incisors is evaluated on the basis of existing anterior facial height. RIC>ETS ANAL=SIS 5)*176 In this analysis mean value are given that change with growth and those that remain stable. 7oints 7t! +ocated at lower border of foramen rotendum. (( 1 Intersection of facial axis and cranial axis i.e. 6 to ?a. i 1 (entroid of ramus 7m 1 7rotrubrance menti between point ? and 7og. Daria.es nor"s S-D- <or * years odFa!e ad@ust 1* %acial axis <> > ±- 6o ad&ustment '* %acial angle :9 > ±- L1 > Every - years -* 2andibular plane '0 > ± . 11 > every - years .* +ower facial height .9 > ± . 6o ad&ustment /* 7alatal plane to 7, > > 41!'./* > 0* (onvexity of point 3 ' ± 'mm 11mm for every - years 9* +I to 3pog 1mm ± ' 6o ad&ustment :* "0 to 7tv 3ge± - increase 1mmHyear upto maturity <* Interincisal 1'' > ± / > 1>* +ower lip to E line 1' ± 'mm +ess protrusive with growth Interpretation '. $. )acial axis Indicate chin is upward and forward or down ward and bac)ward. %. )acial angle Indicate mandibular prognathism or retrognathism. *. +andibular plane angle +ow mandibular plane angle 1 3de$uate ramus height ,igh mandibular plane angle 1 #hort vertical height of ramus ,. &alatal plane to )- Indicate position of nasal floor and it is a ob&ective in orthodontic treatment to bring palatal plane parallel to the %, plane. .. +axillary convexity or convexity of point A ,elps in locating the position of maxilla with relation to cranial base and it can be change with age and with mandibular growth. /. "enture height 3ngle made by connecting 36#, i and 7m points. Its effectiveness represents the denture heights or lower facial height or vertical relation between maxillary and chin. 0. 1( to A &og line ,elps in assessing lower incisor position in relation to existing s)eleton. 2. 3pper molar to &T4 It is the indicator of upper denture position in the arch anteroposteriorly. 5. (nterincisal angle ,elps in assessing degree of proclination or retroclination of maxillary and mandibular incisors. $6. 1ower lip and 7 line 7rotrusion or retrusion of lower lip. '/ '0