Problems beyond the control of the clinician: understanding the genetics underlying orthodontic treatment

Abstract

The interface of genetics and orthodontics has focused primarily on two main areas: 1) the understanding and treatment of craniofacial anomalies; and 2) the prediction of growth and putative limitations of stable treatment in the remain-ing majority of patients. Research on the influence of genetics on developmental variation relevant to standard orthodontic treatment previously has been inferred from familial correlations and heritability studies. Unfortunately, these types of studies are inadequate and inappropriate, respectively, to be of significant use in every day clinical practice. The greatest contribution of genetics to the practice of orthodontics ulti-mately may be a better understanding and accounting for individual growth and development as well as variable responses to treatment. If the component of variation associated with genetic differences could be accounted for, then the effect of environmental (treatment) factors and the effect of their interaction with genetic factors could be determined more precisely. Studies of linkage or association of specific DNA polymorphisms with the trait in multiple families and/or in large population samples are needed not only to demonstrate a genetic influence, but also to determine ultimately what those genetic influences are and how they interact with environmental factors. It is time for large clinical studies of individuals undergoing orthodontic treatment using modern genotyping techniques to determine definitively which specific genetic factors influence growth, development and the response to treatment, so as to understand better the etiology and treatment prognosis for malocclusion.