Maxillary arch width and buccal corridor changes with orthodontic treatment

With great interest and respect, we read the research reported by Anna H. Meyer et al (Meyer AH, Woods MG, Manton DJ. Maxillary arch width and buccal corridor changes with orthodontic treatment. Part 2: attractiveness of the frontal facial smile in extraction and nonextraction outcomes. Am J Orthod Dentofacial Orthop 2014;145:296-304). First and foremost, we would like to appreciate the authors’ effort on conducting this enlightening investigation to assess the esthetic value of buccal corridors as evaluated by orthodontists, dentists, and laypeople on posttreatment full-face photographs. However, we wish to express 2 concerns and ask 1 question pertaining to the report.

The first concern is in relation to the method of rating. We agree with the authors’ opinion that the esthetic assessment of a smile cannot be judged on the smile alone. However, despite their best efforts to instruct all panel members to focus on the smile, the VAS ratings will inevitably produce some bias. So as far as we are concerned, if they adjusted the full-face photograph by covering the eyes, which would lead the raters to focus on the smile naturally without disturbing the balance of the whole face, the outcome would be stricter. As for the display of the images, the consistent order would not have been likely to exert a similar influence on each rater’s score, since the order effect varies between people because of their different characters. So we suggest repeating the images in different orders several times (but in the same order to every rater) and then getting a mean rating.

The second concern is related to the trend of the dentists’ VAS scores. As the result demonstrates, the number of years in practice did significantly affect the ratings of the dentists. But we wondered how the authors drew the conclusion, since we found only 1 dentist with 21 to 30 years in practice in this study, which is too small a sample capacity to get to that. And also, the distribution of the dentists with different years in practice is not equal: 12, 7, and 1 years, respectively.

In addition to the concerns above, we have a question. IC (intercanine distance) is defined as the distance between the most distal surfaces of the canines, whereas IL (interlast visible maxillary tooth distance) is defined as the distance between the most distal surfaces of the last visible maxillary teeth in the article. But as Table III illustrates, the mean of IL:SW is smaller than the mean of IC:SW; that puzzled us because IL should be larger than IC.

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Apr 6, 2017 | Posted by in Orthodontics | Comments Off on Maxillary arch width and buccal corridor changes with orthodontic treatment
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