I read the article in the October 2017 issue entitled “Extraction of maxillary canines: Esthetic perceptions of patient smiles among dental professionals and laypeople” with great interest (Thiruvenkatachari B, Javidi H, Griffiths SE, Shah AA, Sandler J. Am J Orthod Denotofacial Orthop 2017;152:509-15).

The authors have clearly given the message that when the canines are not in favorable positions, there should be no hesitation to consider extracting them. This will not affect the perception of esthetics among dental professionals and laypeople. After reading the article, I thought of the following aspects.

• 1.

  The authors discussed that there was no problem regarding functional occlusion when canines were extracted. I am of the opinion that canine-guided occlusion and group functional occlusion are related when canines are present in the oral cavity. When canines are extracted, there is no need to worry about functional occlusion because the premolars are in their original positions. Whatever the functional occlusion relationship of premolars was before treatment will remain after treatment, if they are in their normal positions. The only change in canine extraction cases is retraction of 4 incisors, which is not going to cause any functional problem.

• 2.

  Regarding the type of study, the authors stated that it was a retrospective study. I am of opinion that it is a cross-sectional observational study because the photographs collected from the records were e-mailed to the assesors, and the data were collected at a specific point of time.

• 3.

  The authors mentioned that the photographs were blinded for extraction choice. I showed copies of the photographs to residents in our department, and all were able to identify the extraction pattern done in the 4 patients. Blinding the photographs might apply to laypeople but not to dental professionals.

• 4.

  The authors mentioned that the measures were rated on a 10-point Likert scale. The Likert scale was developed by psychologist Rensis Likert in 1932. It is used for respondents to specify their level of agreement or disagreement on a symmetric agree-disagree scale with neutral in the middle for a series of statements. For this purpose, the options given to respondents will be always in odd numbers (3, 5, 7, or 9) with the neutral response in the middle, negative on 1 side, and positive on the other side.