Mixed Dentition Analysis / orthodontic courses by Indian dental academy

MIXED DENTITION MIXED DENTITION ANALYSISANALYSIS

INDIAN DENTAL ACADEMY

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MOYERS MIXED DENTITION MOYERS MIXED DENTITION ANALYSISANALYSIS

The purpose of a mixed dentition analysis The purpose of a mixed dentition analysis is to evalute the amount of space available is to evalute the amount of space available in the arch for the erupting permanent in the arch for the erupting permanent canines and premolars. In this analysis the canines and premolars. In this analysis the size of the unerupted permanent cuspids size of the unerupted permanent cuspids and premolars are predicted from the and premolars are predicted from the knowledge of the sizes of certain knowledge of the sizes of certain permanent teeth that are already erupted permanent teeth that are already erupted in the mouth. in the mouth.


The moyers analysis predicts the combined The moyers analysis predicts the combined mesio-distal width of 3,4,5 based on the sum mesio-distal width of 3,4,5 based on the sum of the widths of the four lower permanent of the widths of the four lower permanent incisors.incisors.

the mesio-distal width of the four lower the mesio-distal width of the four lower incisor are measured and summed up.the incisor are measured and summed up.the amount of space available for the 3,4and 5 amount of space available for the 3,4and 5 after incisor alignment is determined by after incisor alignment is determined by measuring the distance between the distal measuring the distance between the distal surface of lateral incisor and the mesial surface of lateral incisor and the mesial surface of first permanent molarsurface of first permanent molar. .


Based on the mesio-distal width of four Based on the mesio-distal width of four mandibular incisors, the expected width of mandibular incisors, the expected width of the canines, first and second premolars are the canines, first and second premolars are predicted by referring the probability chart. predicted by referring the probability chart. While doing so,the 75%level of probability While doing so,the 75%level of probability is considered reliable.is considered reliable.

The predicted tooth size of 3,4,5 is The predicted tooth size of 3,4,5 is compared with arch length available for compared with arch length available for them so as to determine the discrepancy. them so as to determine the discrepancy. If the predicted value is greater than the If the predicted value is greater than the available arch length,crowding of teeth can available arch length,crowding of teeth can be expectedbe expected


Total mandibular width of 345Total mandibular width of 345 incisor width incisor width 19.5 20.6, 20.119.5 20.6, 20.1 20.0 20.9,20.420.0 20.9,20.4 20.5 21.2,20.720.5 21.2,20.7 21.0 21.3,21.021.0 21.3,21.0 21.5 21.8,21.321.5 21.8,21.3 22.0 22.0, 21.622.0 22.0, 21.6 22.5 22.3,21.922.5 22.3,21.9 23.0 22.6,22.223.0 22.6,22.2 23.5 22.9, 22.523.5 22.9, 22.5 24.0 23.1, 22.824.0 23.1, 22.8


HUCKABA’S ANALYSISHUCKABA’S ANALYSIS Here both study cast and radiographs Here both study cast and radiographs

are used for determining the width of are used for determining the width of unerupted tooth.unerupted tooth.

PrinciplePrinciple with any type of radiograph, it is with any type of radiograph, it is

necessary to compensate for necessary to compensate for enlargement of the radiographic image. enlargement of the radiographic image. This can be done by measuring an This can be done by measuring an object that can be seen both in object that can be seen both in radiograph and on the cast.radiograph and on the cast.


YI= X1 xY2/X2YI= X1 xY2/X2 y1= width of unerupted tooth whose y1= width of unerupted tooth whose

measurement is to be determinedmeasurement is to be determined . . y2= width of unerupted tooth on radiograph.y2= width of unerupted tooth on radiograph. X1=width of a tooth that has erupted X1=width of a tooth that has erupted

measured on the cast.measured on the cast. X2=Width of a tooth that has erupted,measured X2=Width of a tooth that has erupted,measured

on the radiographon the radiograph


Accuracy of this method of Accuracy of this method of determining the width of the determining the width of the unerupted tooth is fair to good, unerupted tooth is fair to good, depending upon the quality of the depending upon the quality of the radiographs and their position in the radiographs and their position in the arch arch

this technique can be used in this technique can be used in maxillary and mandibular arches for maxillary and mandibular arches for all ethnic groups.all ethnic groups.


HIXON AND OLD FATHER’S HIXON AND OLD FATHER’S The mesio-distal width of mandibular The mesio-distal width of mandibular

central and lateral incisor is obtained central and lateral incisor is obtained from the casts. Determine the width from the casts. Determine the width of the premolars from the intraoral of the premolars from the intraoral periapical radiographs made using periapical radiographs made using long cone technique. Sum up the long cone technique. Sum up the width of central and lateral incisor width of central and lateral incisor along with the width of unerupted along with the width of unerupted premolars of that particular side.premolars of that particular side.


The estimated sum total width of the The estimated sum total width of the cuspids and bicuspids of that cuspids and bicuspids of that particular side can be obtained from particular side can be obtained from the chart. Every measured sum width the chart. Every measured sum width of incisor and bicuspids has a of incisor and bicuspids has a corresponding sum width of the corresponding sum width of the cuspids and bicuspids in the chart.cuspids and bicuspids in the chart.


measured values estimated tooth measured values estimated tooth sizesize

46 18.446 18.4 47 18.747 18.7 48 19.048 19.0 49 19.449 19.4 50 19.750 19.7 51 20.051 20.0 52 20.352 20.3 53 20.753 20.7 54 21.054 21.0 55 21.355 21.3 56 21.656 21.6


Nance careys analysisNance careys analysisThis analysis is similar to arch perimeter This analysis is similar to arch perimeter

analysis of the permanent dentition.analysis of the permanent dentition.

PROCEDUREPROCEDURE measure the mesio-distal width of the measure the mesio-distal width of the

erupted permanent teeth.erupted permanent teeth.

measure the width of each unerupted tooth, measure the width of each unerupted tooth, cuspids and bicuspids (3,4,5) from the cuspids and bicuspids (3,4,5) from the intra-oral periapical radiographsintra-oral periapical radiographs..


The total mesio-distal width of all the The total mesio-distal width of all the teeth in each quadarent will indicate space teeth in each quadarent will indicate space required to accommodate the permanent required to accommodate the permanent toothtooth

. . using brass wire measure the arch using brass wire measure the arch

perimeter.perimeter.

compare the space required and space compare the space required and space available to arrive at the arch length available to arrive at the arch length discrepancy.discrepancy.


Thank youThank you

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Mixed Dentition Analysis / orthodontic courses by Indian dental academy