bolton analysis
Post on 08-Apr-2015
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Bolton Analysis
The Bolton Analysis
• Determines the ratio of the mesiodistal widths of the maxillary versus the mandibular teeth (i.e., tooth size discrepancy)
• On account of the importance for the canine relation as well as for overbite and overjet relationship
Overall Ratio
• The relationship of the 12 mandibular teeth to the 12 maxillary teeth is assessed
• Second and third molars are exclude
Overall ratio = Sum mand 12 (m-d) x 100Sum max 12 (m-d)
• If the calculated ratio is greater than 91,3 %, the mandibular teeth are too wide compared to the maxillary teeth
• If the ratio is reduced, the maxillary teeth are relatively too large
Anterior Ratio
• Further analysis is performed to evaluate the ratio between the six upper and lower anterior teeth
Anterior ratio = Sum mand 6 (m-d) x 100Sum max 6 (m-d)
• If the ratio is greater than 77,2% the total width of the lower six anterior teeth is relatively too large
• If the index value is reduced, the discrepancy is due to an excess in maxillary tooth material
• It is postulated that the relatively smaller tooth material is the correct one
• Disharmony between the width of upper and lower teeth can be improved by1. extractions2. interdental stripping3. in extreme cases, by increasing the mesiodistal tooth size
Bolton Table
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