532 Readers' forum

treated Class III patients. Am J Orthod Dentofacial Orthop 2010;138:577-81.

2. Cevidanes L, Baccetti T, Franchi L, McNamara JA Jr, De Clerck H.Comparison of two protocols for maxillary protraction: bone an-chors versus face mask with rapid maxillary expansion. Angle Or-thod 2010;80:799-806.

3. Teuscher U. An appraisal of growth and reaction to extraoral an-chorage: simulation of orthodontic-orthopedic results. Am J Orthod1986;89:113-21.

4. Hata S, ItohT,NakagawaM,KamogashiraK, IchikawaK,MatsumotoM,et al. Biomechanical effects of maxillary protraction on the craniofacialcomplex. Am J Orthod Dentofacial Orthop 1987;91:305-11.

5. Cha BK, Ngan PW. Skeletal anchorage for orthopedic correction ofgrowing Class III patients. Semin Orthod 2011;17:124-37.

6. Lee NK, Baek SH, Choi DS, et al. Influence of miniplate shapes asskeletal anchorage for application of orthopedic force: a threedi-mensional finite element analysis. J Korean Assoc Maxillofac PlastReconstr Surg 2008;30:345-52.

7. Kircelli BH, Pektas ZO. Midfacial protraction with skeletally an-chored face mask therapy: a novel approach and preliminary results.Am J Orthod Dentofacial Orthop 2008;133:440-9.

8. Vaughn GA, Vaughn B, Moon HB, Turley PK. The effects of maxil-lary protraction therapy with or without rapid palatal expansion:a prospective, randomized clinical trial. Am J Orthod Dentofacial Or-thop 2005;128:299-309.

9. Ghoneima A, Abdel-Fattah E, Hartsfield J, El-Bedwehi A, Kamel A,Kula K. Effects of rapid maxillary expansion on the cranial and cir-cummaxillary sutures. Am J Orthod Dentofacial Orthop 2011;140:510-9.

Growth patterns in identical twins

Iwas interested in the online case report by Sugawaraet al1 mainly because of their finding that 1-phase

and 2-phase results “showed identical dentofacial char-acteristics,” whereas my own study on 12 identical twinsfound large contrasts between twins treated with func-tional orthodontics at a young age and their identicalsiblings treated at an older age by fixed appliances.2

In looking for possible reasons, I see that, in thisrecent case report, both patients were finished withfixed appliances, as have nearly all previous groupcomparisons of 1- and 2-stage treatments. We knowthat fixed appliances are quite powerful and tosome extent put the teeth and their supporting bonesinto a “straitjacket.” Surely, if it were desired to com-pare the effects of early and late treatments, thereshould be a group treated with growth guidance,but without fixed appliances, as was done in myown research.

In a previous randomized trial comparing early vslater treatment, the authors reported, “We were so im-pressed with the progress of the children receiving earlytreatment that we discussed whether it was ethical todeny the control children.”3 However, they later reportedthat “The differences created disappeared when bothgroups received comprehensive fixed appliance

May 2012 � Vol 141 � Issue 5 American

treatment.” Is it possible that the similarities of “compre-hensive fixed treatment” overwhelmed the differencescreated by the early treatment? Could this give us an al-ternative explanation for why they all finished with sim-ilar results?

There is substantial evidence to suggest that the fa-cial skeleton is more easily influenced before the ageof 8 years, but, because of the apparent overwhelmingevidence of these previous studies, few orthodontiststreat early.4 It is therefore important that we have soundevidence on this central issue, especially since this sameflaw seems to be present in so many other studies. Logicis more important than evidence.

John MewLondon, United Kingdom

Am J Orthod Dentofacial Orthop 2012;141:5320889-5406/$36.00Copyright � 2012 by the American Association of Orthodontists.doi:10.1016/j.ajodo.2012.03.005

REFERENCES

1. Sugawara J, Aymach Z, Hin H, Nanda R. One-phase vs 2-phasetreatment for developing Class III malocclusion: a comparison ofidentical twins. Am J Orthod Dentofacial Orthop 2012;141:e11-22.

2. Mew JRC. Facial changes in identical twins treated by different or-thodontic techniques. World J Orthod 2007;8:174-88.

3. Tulloch JFC, Proffit WR, Phillips C. Outcomes in a 2-phase random-ized clinical trial of early Class II treatment. Am J Orthod DentofacialOrthop 2004;125:657-67.

4. Franchi L, Baccetti T, McNamara JA Jr. Postpubertal assessment oftreatment timing for maxillary expansion and protraction therapyfollowed by fixed appliances. Am J Orthod Dentofacial Orthop2004;126:555-68.

Authors' response

We appreciate the interest Dr Mew has taken in thiscontroversial topic on the orthopedic effects of

early treatment. Since he appears to have conducteda study with a larger number of twins, we were interestedin the insight that his article could provide. In Dr Mew’stwin study, published in 2007 in the World Journal ofOrthodontics, we found that there was no objective eval-uation of skeletal differences, but only differences of fa-cial appearance and dental features.1 In addition, thesample and the material of his study were too heteroge-neous to support his statement that his trademarkedfunctional appliance, used during early treatment, ismore effective than late treatment with traditional fixedappliances.

Dr Mew’s statement that “fixed appliances are quitepowerful and to some extent put the teeth and support-ing bones into a ‘straitjacket’” is unfounded. It is well

Journal of Orthodontics and Dentofacial Orthopedics