Extraction treatment and long-term profile changes

I’d like to make a few comments on the article “Extraction vs no treatment: Long-term facial profile changes” in the May 2015 issue (Rathod AB, Araujo E, Vaden JL, Behrents RG, Oliver DR. Am J Orthod Dentofacial Orthop 2015;147:596-603). This is a most interesting and pertinent topic of research in orthodontics. In the introduction, the authors stated that “Tweed challenged Angle’s concepts [on nonextraction treatment] solely on esthetic grounds [italics added].” A review of Tweed’s early papers on the subject show that relapse of incisor alignment was actually Tweed’s initial concern. In the second sentence of Tweed’s 1936 paper, he stated that “the most unstable and therefore the most difficult cases to retain successfully are those in which teeth are too far forward or in double protrusion.”

The size of the face, especially after treatment, was significantly different between the treated and the untreated samples: faces and features in the treated sample were much larger, especially the nose and lower facial height. No information was given about the mean ages of the samples at T2 and T3, only that they were chosen in an attempt to match the 10- to 17-year posttreatment films. There also was no information about the numbers of male and female subjects in each sample. Might the treated sample have been older, or had more male subjects? A table presenting such information would have been helpful. It would have been interesting to compare these samples at T1 to see whether they were more similar at pretreatment.

I question the use of Ricketts’ E-plane and the mean values associated with an “esthetic face.” Ricketts’ finding of the lower lip located 4 mm behind the E-plane was not from a sample of beautiful faces. This was a finding from an analysis of 1000 consecutively treated patients in his practice. Hence, one cannot conclude, since the values in Ricketts’ study and this study were similar, that these patients were esthetically acceptable. In addition, Ricketts’ article was published almost 50 years ago (1968), and studies have shown that the esthetic face in 1968 had thinner lips than those in the later part of the 20th century. This article, although very interesting and informative, did not study esthetics; it simply evaluated the hard and soft tissue changes incident to treatment with extraction vs normal growth.

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Apr 6, 2017 | Posted by in Orthodontics | Comments Off on Extraction treatment and long-term profile changes

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