正畸治疗前的模型分析和投影测量分析

Tooth size analysis
Analysis of Diagnostic Records
Dental cast analysis
to evaluate space excess or deficiency and symmetry within the dental arches
Two parts
Northern European white children
No radiographs are required , used for the upper or lower arch.
Estimation from proportionality tables
Estimating of Unerupted Permanent Teeth
Periapical radiographs Panoramic radiographs.
Measurement of the teeth on radiographs
True width of primary molar
Apparent width of primary molar
=
True width of unerupted Premolar Apparent width of unerupted premolar
Symmetry
Transparent ruled grid placed over dental cast Oriented to the midpalatal raphe Spot asymmetries in arch form , and tooth position
Symmetry
Cephalometric analysis of dentofacial relationships
Cephalometric analysis
The introduction of radiographic cephalometrics is in 1934 by Hofrath in Germany and Broadbent in USA.
Space Analysis
Three assumptions
01
Correct anteroposterior position of incisors
02
03
The space available will not change because of growth.
All the teeth are normal in size
Three assumptions
01 02 03
Correct anteroposterior position of incisors
The space available will not change because of growth.
All the teeth are normal in size
teeth and incisal edge of anteriors.
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.
Measurement of the teeth on radiographs
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.
Prediction table methods
Radiograghic
Combination
Combination of radiographic and prediction table
It depends!
Comparison
1 Depending on the quality of the radiographs and their position in the arch
Lateral drift of incisors (Crowding, C lost 3 blocked out)
Drift of posterior teeth （Early loss of E)
Pendulum
Dental cast analysis
Symmetry
Space analysis Estimating of unerupted permanent teeth
Function
For all ethnic groups. 2 Northern European white children No radiographs 3
Most practical
Northern European white children No radiograghs
No reference table
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)
Operator : Zhou Ling
Supervisor: Prof. Li Date: 2013.6.6
Chapter outline
1
2
The Problem-Oriented approach Clinical Evaluation Analysis of Diagnostic Records
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.
Tooth Size Analysis
Tooth Size Analysis
Bolton Ratio
(78.8 ±1.72)%
(91.5 ± 1.51)%
Tooth Size Analysis
A quick check for ….
Anterior tooth size discrepancy : 2 > 2
3 4
Orthodontic Classification Development of a Problem List
5
Analysis of Diagnostic Records
Dental cast analysis to evaluate space excess or deficiency and symmetry within the dental arches
Tooth size analysis
Alignment (Crowding): Space Analysis
Space Analysis
Dental cast
Computer algorithm
Step one: Calculation of available space
Measuring arch perimeter from the mesial of one first molar to the other, over the contact points of posterior
Estimating of Unerupted Permanent Teeth
Prediction table methods Radiograghic
Combination
Estimation from proportionality tables
Moyers prediction
Measuring the mesiodistal width of the lower incisors
Three assumptions
01 02
Correct anteroposterior position of incisors
The space available will not change because of growth.
All the teeth are normal in size
Posterior tooth size discrepancy： 5 = 5 A tooth size discrepancy of less than 1.5mm is rarely significant.
Dental cast analysis
Symmetry
Space analysis Estimating of unerupted permanent teeth
Estimating of Unerupted Permanent Teeth
Prediction table methods
Combination
Radiograghic
Measurement of the teeth on radiographs
Undistorted radiographic image Compensate for enlargement
Radiograghic
MoyFra Baidu bibliotekrs
Takana & Johnston
Dental cast analysis
Symmetry
Space analysis Estimating of unerupted permanent teeth
Tooth size analysis
Tooth Size Analysis
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.
03
Dental cast analysis
Symmetry
Space analysis Estimating of unerupted permanent teeth
Tooth size analysis
Mix Dentition Estimating of Unerupted Permanent Teeth
Two parts
Cephalometric analysis of dentofacial relationships
Dental cast analysis
Symmetry
Space analysis Estimating of unerupted permanent teeth
Tooth size analysis
Prediction the size of both the lower and upper unerupted canines and premolars
Estimation from proportionality tables
Estimation from proportionality tables