Читать книгу Biological Mechanisms of Tooth Movement - Группа авторов - Страница 23

Orthodontics started with the use of a finger or a piece of wood to apply pressure to crowns of malposed teeth. The success of those manipulations proved convincingly that mechanical force is an effective means to correct malocclusions. Until the early years of the twentieth century, understanding the reasons why teeth move when subjected to mechanical forces was only a guess, based on reason and empirical clinical observations. Farrar hypothesized in 1888 that teeth are moved orthodontically due to resorption of the dental alveolar socket and/or bending of the alveolar bone. Both hypotheses were proven to be correct during the twentieth century, as orthodontic research has spread into increasingly fundamental levels of biological basic research. The rationale for these basic investigations was the wish to unveil the mechanism of translation of mechanical signals into biological/clinical responses; the etiology of iatrogenic effects resulting from OTM; and to discover efficient means to shorten significantly the duration of OTM. Many details on the behavior of cells involved in OTM have emerged from those investigations but, despite this progress, the final answer to the above issues remains elusive.

At present, molecular biology and molecular genetics remain at the cutting edge of orthodontic research. Multiple genes that may be involved in the cellular response to mechanical loads have been identified (Reyna et al., 2006), and genes associated with orthodontic‐induced root resorption (Abass and Hartsfield, 2006). The role played by specific genes in OTM was revealed by Kanzaki et al. (2004), who reported that a transfer of an OPG gene into the PDL in rats inhibits OTM by inhibiting RANKL‐mediated osteoclastogenesis. According to Franceschi (2005), future efforts in dental research will include genetic engineering, focusing on bone regeneration. Recently, Zhao et al. (2012), through experiments in male Wistar rats, reported inhibition of relapse with local OPG gene transfer through the inhibition of osteoclastogenesis.

The body of knowledge that has evolved from multilevel orthodontic research supports the notion that the patient’s biology is an integral part of orthodontic diagnosis, treatment planning, and treatment. Therefore, orthodontic appliances and procedures should be designed to address the patient’s malocclusion in light of his/her biological profile, in much the same fashion as is done by medical specialists in other fields of medicine. As outlined by Jheon et al. (2017), analyses of genetic and molecular factors may soon uncover indicators predicting slow tooth movement, increased predisposition to root resorption, and accelerated late stage skeletal growth. Patients will be provided with customized appliances printed through the treatment stages, as per the devised virtual plan. In addition, specific biologic/pharmacologic agents based on patients’ molecular and genetic background will be delivered to enhance treatment efficiency and outcomes.

Orthodontics started in ancient times by pushing malposed teeth with a finger for a few minutes a day, but today we know that the reason teeth can be moved is because cells respond to changes in their physical and chemical environment. Research will continue to unravel new details of this process, and the beneficiaries will be all people seeking and receiving orthodontic care.