had either ideal or long lower ante-rior face height. He concluded that vertical control was an important aspect of Class II correction. By combining these studies, we now know that the most unattrac-tive facial profiles are long face profiles. We also know that most Class II malocclusions have verti-cal dimensions that are either ideal or vertically excessive. There-fore, control in the vertical dimen-sion is vitally important in orthodontic treatment. The Importance of Vertical Control Fig. 5 This brings us to what I believe is the most important study ever done regarding orthodontic diagnosis and treatment. It was done by Prof. Arnie Bjork. After practicing orthodontics for 25 years, Prof. Bjork accepted the post of Chair-man of the orthodontic department at a Danish University. Once he accepted this position, he never again treated another case but instead focused on this study. This study has become one of the land-mark studies regarding facial growth and development. In this study, Prof. Bjork moni-tored the growth of 248 children. No treatment was performed on these patients. He took records on these kids every year, but what makes this study so valuable is that he also placed metallic implants in the maxillas and mandibles of these growing children. (Fig. 5) These implants provided a reliable method of superimposition of the cephalometric x-rays. The main reason that this study is so valu-able is that it can never be dupli-cated because of ethical concerns. Prof. Bjork observed some severe malocclusions as they worsened. In today's environment not treating these cases is unethical because of the harm done to the patient by not treating. Additionally, placing implants in children for observa-tion only would today be unethi-cal, whereas it was not considered unethical in the 1950s when Prof. Bjork performed the study. Note: it is interesting to observe the “crude” technique of implant Fig. 6 Fig. 7 the components of Class II occlu-sions. The results of the study showed that almost 90% of Class II patients (this was measured by using the mandibular plane angle as well as lower anterior face height) 18 Spring 2020 JAOS
Journal of the American Orthodontic Society Spring 2020: Page 18
