Letters to the editor
2003; Elsevier BV; Volume: 124; Issue: 1 Linguagem: Inglês
10.1016/s0889-5406(03)00395-0
ISSN1097-6752
Autores Tópico(s)Veterinary Practice and Education Studies
ResumoI read the article, “Arch width after extraction and nonextraction treatment,” by Anthony Gianelly (Am J Orthod Dentofacial Orthop 2003;123:25-8), in the January 2003 issue of the Journal with great disappointment. It is yet another attempt by those of the old guard in orthodontics to keep a golden safety net under the premolar extraction technique, claiming it is totally innocent of certain criticisms leveled against it. Let us explore this a bit further. First, why was the data not normalized? Second, the premolar extraction technique is, in and of itself, neither good nor bad; it is merely a technique. It does certain things. If you want those things, fine; if you do not want those things, then maybe this technique should not be used on a given patient. Dr Gianelly states that, according to his study of plaster models, arches receiving premolar extraction are, on average, no narrower than those that do not have those teeth removed. In fact, he states that intercanine width is actually greater in the extraction arches. He has measured them. But the measurements he reports are only averages. That means some are more, some less. Patients on the downside of this calculation are not comforted by being told they are part of an average. For them, a posttreatment smile that is less than what it should be stays with them 100% of the time. But what do these measurements really tell us? Only how wide the arches he measured were after extraction. What would the same arches be like if the premolars had not been removed? Would they have been wider yet? Or would they have been longer anteroposteriorly? If so, where: front or back? It must be something. Let X equal the arch length from second molar to second molar of a posttreatment arch in which the first premolars had been extracted. Add 14 mm of extra dentition, ie, two 7-mm wide premolars, and the arch length becomes X + 14. Can that ever be equal to X? Not in any of my algebra classes. Conversely, let Y represent the arch length of a nonextracted arch. Remove two 7-mm premolars, and the total arch length of the rearranged arch with extraction spaces closed would have to be Y − 14. Will that make the resultant arch narrower? According to Dr Gianelly, it will not. Then by default, it must make the arch shorter in the anteroposterior dimension; otherwise, Y would be the same as Y − 14. Absurd, of course. Another thing must be clarified: intercanine width is important, but it does not, in my opinion, determine the quality of broadness of smile. Premolar positioning determines that. No measurements of the width across the remaining premolars of the nonextraction patients were taken and compared with the widths across the arches of the 2 premolars of the nonextraction subjects. In the extraction patients, was the first molar moved forward the entire 7 mm to fill in the space? If not, then how much was it moved? And was the distance along the buccal corridor in the nonextraction subjects a straight line or a parabolic curve? Are we dealing with plane geometry or solid or even spheroid geometry? If the latter, are linear measurements appropriate in describing spheroid realities? And as long as we are clarifying things, why wasn’t the most important relationship of all addressed in this study—the distance from the frontal plane of the smile line of the lips to the overall anteroposterior seating of the denture? The critical feature here may not be so much arch width but rather arch location. The more retruded the arch, the greater the likelihood that it will not fill the open gap of the horizontal plane of the smile, hence the greater the chance for dark triangles. This issue of arch location is not addressed in Dr Gianelly’s article. Why? The real questions are these: Where do all the “orthodontically flattened” faces we see come from? Why do people like Drew Barrymore, Goldie Hawn, and Meg Ryan have dark triangles at the comers of their mouths when they smile, when people like Julia Roberts or Mary Tyler Moore do not? How come Dr Gianelly never showed a photograph of a single face to go with all those models he measured? Where does the criticism of the premolar extraction technique, long prominent, gain its force? The human eye is quite perceptive, and the facial recognition centers in the brain are especially acute. Why does an infant “look like his father,” when, with their tiny, fat, cherubic faces, all infants look alike? What is the difference between the beauty contest winner and the also-rans? How can a mother tell by just a glance that her 4-year-old is getting sick? These examples suggest that even the slightest variance in facial anatomy is discernable. So what do we have here? Dr Gianelly’s article raises many questions and proffers an opinion or proposition inconsistent with commonly observed reality. The criticisms of the unesthetic effects of premolar extraction on the face are not meant to be quid pro quo, pari passu. Only certain patients exhibit these untoward effects. Dr Gianelly’s final statement in the article, “therefore, the esthetically compromising effect of narrow dental arches on smiles is not a systematic outcome of extraction treatment,” is an absolute and mutually exclusive supposition that at best represents a syllogistic non sequitur that is logically without merit. Mere plaster models cannot tell us about human faces or the lip support they do or do not provide, nor can they be put in a time machine and sent back to see how they would fare if treated nonextraction. Sofor all the hard work involved and all the seemingly definitive data collected, Dr Gianelly’s article doesn’t prove anything. It only raises more questions. Is this progress? Ask a disgruntled patient with an unesthetic 4-premolar extraction result! 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