Extraction: A Parameter in Bolton Ratio

Aims: To evaluate extraction as a parameter in determination of Bolton ratio in class II division 1 cases. Materials and Methods: Thirty Class II division 1 cases were selected from the records. Bolton overall ratio was calculated. Hypothetically extraction of four different combinations of premolars was done. These combinations were: Upper first premolar, all first premolars, upper first premolars and lower second premolar, all second premolar. The hypothetical extraction was done by substituting zero in place of the corresponding premolars that were removed. The overall ratios were measured again. Results and Conclusion: (1) Extraction can be considered as a parameter in evaluating Bolton ratio. (2) In upper first premolar extraction Bolton ratio increased. (3) When all first premolar, upper first and lower second premolar, all second premolar were extracted the ratio decreased. (4) In all four first premolar, all second premolar, upper four and lower five premolar extraction can be carried out without much affecting Bolton ratio in class II division 1 cases