It was fascinating to read the retrospective research article in the September issue comparing 2 contrasting conventional strategies to treat growing hyperdivergent patients (Gkantidis N, Halazonetis DJ, Alexandropoulos E, Haralabakis NB. Treatment strategies for patients with hyperdivergent Class II Division 1 malocclusion: is vertical dimension affected? Am J Orthod Dentofacial Orthop 2011;140:346-55). One method was a nonextraction approach with extrusive mechanics, and the other was an extraction approach with intrusive mechanics. One aim was to study the wedge-effect phenomenon, which has implications in the control of vertical dimensions. Although clinically important conclusions were made from the study, some additional points could have been described or considered that might have led to additional important conclusions.
First, which type of intrusive mechanics was used for the extraction patients? As stated in the methods section, Goshgarian arches were used. But it has been shown that these are effective for holding molars vertically and not for intruding them. Second, the inclusion of the second molars should have been avoided, since it can lead to opening the bite.
How was 5 mm of mesialization of the mandibular molars achieved in the extraction patients, since no additional mechanics were used, such as Class II elastics?
The wedge-effect concept can also be applied when distalization of molars is attempted; this should have been considered for the nonextraction patients. In such patients, the use of low-pull headgear for distalization can increase the vertical dimension.
One important variable in hyperdivergent patients is vertical movement of the molars. This is a major problem; in this study, this factor needed more discussion.
I do agree with the conclusions drawn from the study, but indirectly it also highlights the importance of newer vertical holding mechanics such as temporary anchorage devices as well as functional treatments. It would be fascinating to view the comparison between conventional mechanics with additional vertical holding mechanics and modified functional strategies.
This is one of the few articles on vertical dimensions that highlights the role of skeletal as well as neuromuscular functions in hyperdivergent patients by using contrasting treatment strategies. I commend the authors for their interesting and thought-provoking article.