I Basic study on the occurrence and treatment of malocclusion

       （1） Study on physiological and biomechanical properties of periodontal tissue

       （2） Study on the biomechanical changes of periodontal tissue under the action of Zhengwei force, study on the mechanism of signal pathway, periodontal ligament is a unique oral tissue structure, which has important physiological significance for the function and health of oral and maxillofacial system. Orthodontic force is applied to thousands of teeth and transmitted to periodontal ligament, causing the biomechanical response of periodontal ligament, and study the biomechanical properties of periodontal ligament and the response and reconstruction of cells to mechanical stimulation, It is the key subject of tooth movement caused by orthodontic force. Although the research on periodontal ligament biomechanics has gradually increased in recent ten years, the biological properties and cellular and molecular mechanisms of periodontal ligament are quite complex. In the dynamic change process of orthodontic force, the research on the mechanism of periodontal adaptive remodeling is far from enough to clarify        the biological effects of tooth movement.

       （3） Gene level changes in tooth movement caused by masazaki

       By means of molecular biology, the function of the protein encoded by the gene is changed, so as to change the induction of cells to mechanical signals.

       （4） Development of drugs or molecular preparations to control tooth movement

       The research and development of drugs or biological agents can promote orthodontic tooth movement or control unwanted tooth movement, and promote bone development and growth, and intervene at the gene level to achieve the purpose of treatment. Although some drugs or protein factors have been applied locally or systemically to thousands of animals, which does have the effect of changing the tooth movement rate, this is only an animal experiment, and there is a lack of sufficient positive data of large sting to support its safety and effectiveness.

       2、 Biomechanical study of orthodontic clinic

       （1） Mechanical properties of invisible appliance

       The pursuit of beauty in modern society is higher and higher. The birth of invisible appliance can better solve the aesthetic problem in the process of patients' correction. The mechanical properties of invisible appliance are studied by three-dimensional finite element method. Although invisible orthodontics has not been widely used at present, more and more biomechanical studies focus on the efficiency of the appliance on tooth movement, so as to obtain the best clinical orthodontic effect. It will not only meet the needs of patients in aesthetics, but also be a great leap in orthodontic technology if it can be beautiful or even optimized with the traditional appliance in curative effect.

       （2） Discovery and application of new materials

       The development of orthodontics is inseparable from the development and application of materials science. In recent years, new brackets, steel wires and orthodontic devices have been born, which is inseparable from the development of biomechanics. It is a general trend to integrate the research of material biomechanics into the R & D and application of new orthodontic materials.

       （3） Biomechanical effects of distraction osteogenesis

       The biomechanical mechanism of distraction osteogenesis is unclear.

       （4） Design improvement of implant

       Micro implants are widely used in orthodontic clinic. The current research mostly focuses on the stability of implants after stress, but the biological changes of surrounding bone tissue or periodontal tissue after implant implantation are not clear. The biomechanical study of implants will help thousands to develop implants that are more conducive to the control of afterforce, comfortable for patients and less damage.

       （5） Clinical mechanical testing

       In orthodontic biomechanical research, thousands of micro sensors are used to detect the force and displacement of teeth, and the methods to detect the force of teeth and mandibular joints under occlusal function.