Personalized Orthodontics, The Future of Genetics in Practice

Presence of single nucleotide polymorphisms in transforming growth factor β and insulin-like growth factor 1 in class II malocclusions due to retrognathic mandible

AIM

The aim of this study was to evaluate specific single nucleotide polymorphisms (SNP) of transforming growth factor-beta (TGF-β) (rs1800469) and insulin-like growth factor-1 (IGF-1) (rs17032362) genes in Class II individuals with a normal maxilla and retrognathic (short) mandible.

Differential gene expression and protein-protein interaction networks of human periodontal ligament stromal cells under mechanical tension

Orthodontic treatment is based on complex strategies and takes up to years until a desired therapeutic outcome is accomplished, implying long periods of high costs and discomfort for the patient. Choosing the optimal settings for force intensities in the initial phase of orthodontic tooth movement is the key to successful orthodontic treatment. It is known that orthodontic tooth movement is mainly mediated by tensile and compressive forces that are communicated to the alveolar bone via the periodontal ligament. While the revelation of the complex molecular network was already approached by transcriptomic analysis of compressed periodontal ligament cells, the entity of molecular key players activated by tensile forces remains elusive. Therefore, the aim of this study was to assess the effect of mechanical tensile forces on the gene expression profile of human primary periodontal ligament stromal cells, mimicking the initial phase of orthodontic tooth movement. A transcriptomic analysis of tension-treated and untreated periodontal ligament stromal cells yielded 543 upregulated and 793 downregulated differentially expressed genes. Finally, six highly significant genes were found in the transcriptome that are related to biological processes with relevance to orthodontic tooth movement, including apelin, fibroblast growth factor receptor 2, noggin, sulfatase 1, secreted frizzled-related protein 4 and stanniocalcin 1. Additionally, differences of gene expression profiles between individual cell donors showed a high effect size. Closer understanding of the roles of the identified candidates in the initial phase of orthodontic tooth movement could help to clarify the underlying mechanisms, which will be essential for the development of personalized treatment strategies in orthodontics.

Evolving concepts of heredity and genetics in orthodontics

The field of genetics emerged from the study of heredity early in the 20th century. Since that time, genetics has progressed through a series of defined eras based on a number of major conceptual and technical advances. Orthodontics also progressed through a series of conceptual stages over the past 100 years based in part on the ongoing and often circular debate about the relative importance of heredity (nature) and the local environment (nurture) in the etiology and treatment of malocclusion and dentofacial deformities. During the past 20 years, significant advancements in understanding the genomic basis of craniofacial development and the gene variants associated with dentofacial deformities have resulted in a convergence of the principles and concepts in genetics and in orthodontics that will lead to significant advancement of orthodontic treatments. Fundamental concepts from genetics and applied translational research in orthodontics provide a foundation for a new emphasis on precision orthodontics, which will establish a modern genomic basis for major improvements in the treatment of malocclusion and dentofacial deformities as well as many other areas of concern to orthodontists through the assessment of gene variants on a patient-by-patient basis.