Re Response to: Mandibular growth comparisons of Class I and Class II division 1 skeletofacial patterns by Helder B. Jacob and Peter H. Buschang. The Angle Orthod. 2014;84:755–761.

To: Editor, The Angle Orthodontist

First, we want to thank Dr Soumya N. Thirumoorthy for her interest in our article entitled “Mandibular growth comparisons of Class I and Class II division 1 skeletal patterns.” She expressed concern with the selection of our Class II sample, which was classified based on molar and canine relationships.

We agree that the outcome would have been somewhat different if we had only included mandibular retrusive Class II's. The growth differences that we identified would have probably been more pronounced because the patients would have been relatively more hyperdivergent. Our more recent analyses indicate that hyperdivergent Class II's have the most pronounced growth deficiencies than either hyperdivergent Class I's or hypodivergent Class II's.

However, limiting the sample to retrusive subjects would have reduced our already limited sample size, which holds statistical implications. More importantly, we would have been focusing on a subset of Class II's. We wanted to be able to say something about all Class II division 1's. Finally, restricting the sample to mandibular retrusive Class II's has implications for the Class I sample, which also would have had to have been restricted.