6: Palatal canines

6 Palatal canines



image What factors are implicated in maxillary canine ectopia?

The aetiology of maxillary canine ectopia is obscure but most probably multifactorial. Possible causative factors are:

Note in Diane’s case, the mesiodistal width of 2’s were the same as those of image’s, indicating that 2’s are smaller than average and that a tooth-size discrepancy (TSD) or Bolton discrepancy exists between the upper and lower labial segment teeth.

Computational method

A tooth-size analysis, often referred to as a Bolton analysis after its developer, may also be performed. The mesiodistal width of each permanent tooth, excluding second and third molars, is measured and then the summed widths of the maxillary to mandibular teeth are compared with a standard table. This allows calculation of Bolton anterior (canine to canine) and overall (first molar to first molar) ratios as follows:

Bolton obtained an anterior ratio of 77.2 ± 1.65% and an overall ratio of 91.3 ± 1.91%. Discrepancies greater than 2SD beyond these mean values have been regarded as clinically relevant to treatment planning. Tooth-size analysis may also be undertaken using digital models; the measurements are as accurate and reliable as those obtained from plaster models.


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Jan 2, 2015 | Posted by in Orthodontics | Comments Off on 6: Palatal canines
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