diagnostic aids in_orthodontics
TRANSCRIPT
Diagnostic aids in orthodontics
Orthodontic study castThey are
accurate plaster reproductions of the teeth and their surrounding soft tissues
Orthodontic study cast
Orthodontic study castUses of study models:
1.Assist and record dental anatomy
2. Assist and record intercuspation3. Assist and record arch form4. Assist and record the curves of
occlusion 5. Calculate total space analysis6. Measure progress during
treatment7.Medico legal documentation
Orthodontic study castPont’s analysis:Measurement of the 4 maxillary
incisors automatically establish the width of the arch in the premolar and molar region by using :
Calculated premolar value= SI x 100 80 Calculated molar value = SI x 100 64Measured premolar and molar value
is obtained from the distance between distal end of the occlusal groove
(SI = the sum of incisors)
Orthodontic study castCarey’s analysis Is to discover the arch length –
tooth size discrepancy
Orthodontic study castAvailable
space required space
Spacing
Crowding
Normal
Orthodontic study castBolton AnalysisTo determine the
disproportion between the size of the maxillary and mandibular teeth
Overall ratio= sum of mand12 x 100
sum of maxOverall Ratio = 91.3%
Anterior ratio= sum of mand6x 100 sum of max
Anterior ratio = 77.2%
Orthodontic study castmixed dentiton analysis:Used to evaluate the amount of
space available in the arch for succeeding permanent teeth
Moyer’s mixed dentition analysis
By using prediction charts
Tanaka and Johnson analysis
Predicted width of canine and premolar
Maxillary= sum of mandibular incisors + 11 2
Mandibular= sum of mandibular incisors + 10.5 2
Orthodontic study cast
Unerupted tooth size =
Erupted tooth on cast X uneurpted on xray Erupted on x-
ray