正畸治疗前的模型分析和投影测量分析.ppt

Orthodontic diagnosis:The development of a Problem List,Operator:Zhou LingSupervisor:Prof.Li Date:2013.6.6,1,5,3,4,Development of a Problem List,The Problem-Oriented approach,Clinical Evaluation,Analysis of Diagnostic Records,Orthodontic Classification,Chapter outline,2,Analysis of Diagnostic Records,Cephalometric analysis of dentofacial relationships,Dental cast analysis,to evaluate space excess or deficiency and symmetry within the dental arches,Symmetry Space analysis Estimating of unerupted permanent teeth Tooth size analysis,Dental cast analysis,Symmetry,Transparent ruled grid placed over dental cast Oriented to the midpalatal raphe Spot asymmetries in arch form,and tooth position,Lateral drift of incisors(Crowding,C lost 3 blocked out),Symmetry,Drift of posterior teeth（Early loss of E),Pendulum,Symmetry Space analysis Estimating of unerupted permanent teeth Tooth size analysis,Dental cast analysis,Alignment(Crowding):Space Analysis,Dental cast,Computer algorithm,Space Analysis,Measuring arch perimeter from the mesial of one first molar to the other,over the contact points of posterior teeth and incisal edge of anteriors.,Step one:Calculation of available space,片段法,铜丝法,Step two:Calculation of required space,Measure the mesiodistal width of each erupted tooth from contact point to contact point.,Space Analysis,01,The space available will not change because of growth.,02,All the teeth are normal in size,03,Correct anteroposterior position of incisors,Three assumptions,Interaction,Protrusion,Retrusion,Crowding,Crowding and protrusion are different aspects of the same phenomenon.If there is not enough room to properly align the teeth,the result can be crowding,protrusion,or(most likely)some combination of the two.,01,The space available will not change because of growth.,02,All the teeth are normal in size,03,Correct anteroposterior position of incisors,Three assumptions,In a child with a well-proportioned face,there is little or no tendency for the dentition to be displaced relative to the jaw during growth.But the teeth often shift anteriorly or posteriorly in a child with a jaw discrepancy.,01,The space available will not change because of growth.,02,All the teeth are normal in size,03,Correct anteroposterior position of incisors,Three assumptions,Symmetry Space analysis Estimating of unerupted permanent teeth Tooth size analysis,Dental cast analysis,Mix Dentition Estimating of Unerupted Permanent Teeth,Estimating of Unerupted Permanent Teeth,Undistorted radiographic image,Compensate for enlargement,Measurement of the teeth on radiographs,True width of primary molarApparent width of primary molar,Measurement of the teeth on radiographs,True width of unerupted PremolarApparent width of unerupted premolar,=,Accuracy is fair to good depending on the quality of the radiographs and their position in the arch.The technique can be used in maxillary and mandibular arches for all ethnic groups.,Measurement of the teeth on radiographs,Estimating of Unerupted Permanent Teeth,Moyers prediction,Estimation from proportionality tables,Measuring the mesiodistal width of the lower incisors,Prediction the size of both the lower and upper unerupted canines and premolars,Estimation from proportionality tables,Northern European white childrenNo radiographs are required,used for the upper or lower arch.,Estimation from proportionality tables,Estimation from proportionality tables,Estimating of Unerupted Permanent Teeth,Combination of radiographic and prediction table,It depends!,Comparison,Moyers,Takana&Johnston,Northern European white childrenNo radiographs,Depending on the quality of the radiographs and their position in the archFor all ethnic groups.,Symmetry Space analysis Estimating of unerupted permanent teeth Tooth size analysis,Dental cast analysis,Although the natural teeth match very well in most individuals,approximately 5%of the population have some degree of disproportion among the sizes of individual teeth.-Tooth Size Discrepancy(TSD),Tooth Size Analysis,Tooth Size Analysis,Bolton Ratio,Tooth Size Analysis,(78.8 1.72)%(91.5 1.51)%,A quick check for.Anterior tooth size discrepancy:2 2 Posterior tooth size discrepancy：5=5 A tooth size discrepancy of less than 1.5mm is rarely significant.,Tooth Size Analysis,Symmetry Space analysis Estimating of unerupted permanent teeth Tooth size analysis,Dental cast analysis,Analysis of Diagnostic Records,Cephalometric analysis of dentofacial relationships,Dental cast analysis,to evaluate space excess or deficiency and symmetry within the dental arches,The introduction of radiographic cephalometrics is in 1934 by Hofrath in Germany and Broadbent in USA.,Cephalometric analysis,Function,Original purpose Evaluating dentofacial proportions and clarify the anatomic basis for a malocclusion Observing pathologic changes(Sometimes),Researching on growth patterns in the craniofacial complex.,This patient has fusion of the 1st and 2nd cervical vertebrae,with the odontoid process extending into the margin of foramen.,Function,Function,Original purpose Evaluating dentofacial proportions and clarify the anatomic basis for a malocclusion Observing pathologic changes(Sometimes)Recognizing and evaluating changes brought about by orthodontic treatment.,Researching on growth patterns in the craniofacial complex.,Function,The goal of cephalometric analysis is to evaluate the relationships,both horizontally and vertically,of the five major functional components of the face.,Cephalometric analysis,Cephalometric analysis,Cranial Base S，N，Po，Ba,Bo Maxilla Or，Ptm，ANS，PNS，A，UI Mandibular Co，Go，B，LI，Pog，Me，Gn,Cephalometric Landmarks,S.sella N.nasion Po.porion Ba.basion Bo,Cephalometric Landmarks,Or.orbitale Ptm.ANS.Anterior nasal spine PNS Posterior nasal spine A.subspinale UI.Upper Incisor,Cephalometric Landmarks,Co.condylion Go.gonion Pog.pogonion Me.menton Gn.gnathion B.supramental LI.lower incisor,Cephalometric Landmarks,Cephalometric analysis,Contemporary measurement approach,Choice of a Horizontal(Cranial)Reference Line.Steiner Analysis Sassouni Analysis Wits Analysis,Choice of a Horizontal Reference Line,An international congress was held in Frankfort,Germany in 1882.with the choice of a horizontal reference line for orientation of skulls,“Machine porion:The upper surface of the ear rod of the cephalometric Anatomic porion”:The upper surface of the shadow of the auditory canal.,Choice of a Horizontal Reference Line,NHP(natural head position):Relaxed individuals look at a distant obiect or into their own eyes in a mirror and incline their heads up and down in increasingly smaller movements until they feel comfortably positioned.,Choice of a Horizontal Reference Line,Choice of a Horizontal(Cranial)Reference Line.Steiner AnalysisSassouni AnalysisWits Analysis,Contemporary measurement approach,Steiner Analysis,SNA:Maxilla to the cranial base 82 2 SNB：Mandible to the CB 78 2 ANB:skeletal jaw discrepancy.SN-MP(mandiblar plane):Vertical position of the mandible.,ANB angle is influenced by two factors:Vertical height of the face.Anteroposterior position of nasion.,Steiner Analysis,Steiner Analysis,U1-NA（mm)U1-NA L1-NB（mm)L1-NB,Holdaway Ratio:,The balance between the prominence of the chin and the prominence of the lower incisor:the more prominent the chin,the more prominent the incisor can be。,Steiner Analysis,Steiner Analysis,Steiner Analysis,Choice of a Horizontal(Cranial)Reference Line.Steiner AnalysisSassouni AnalysisWits Analysis,Contemporary measurement approach,skeletal open bite,SN FH PP OP MP,Sassouni Analysis,Choice of a Horizontal(Cranial)Reference Line.Steiner AnalysisSassouni AnalysisWits Analysis,Contemporary measurement approach,Wits Analysis,Wits analysis（overcome the limitations of ANB as an indicator of jaw discrepancy)It is based on a projection of points A and B to the occlusal plane,along which the linear difference between these points is measured.,occlusal plane（OP）,Female:0Male:-1,First step:pick the correct template from the set of age-different ones that represent the reference data.Two things must be kept in mind:(1)the patients physical size(2)his or her developmental age,Template Analysis,Sequence of superimposition,Cranial base superimposition,Maximum contour of the maxilla,Symphysis of themandible,Cranial base superimposition,Maximum contour of the maxilla,Symphysis of the mandible,Thank you!,