Oral Orthodontic Force Simulationand Tooth Movement Modulation Research

Although contemporary orthodontics have established a relatively complete system, treatment planning and design of loading equipment for the clinical treatment are still severe rely on the personal experience of orthodontists. While they can’t predict the character of force which produce by loading equipment, then the patients need frequent reexamination and adjustment, this method is called as “trail and error”. This way not only lengthen treatment time and increase the cost of treatment, but also bring additional side effects. Up to now, the study of tooth movement modulation and the equipment design are still sparse, and no effective guidance as for the clinical orthodontic treatment. Therefore, on account of above situation, this paper will study the source and reasonabl e of orthodontic force, and how to accelerate tooth movement without serious side effects.It is so troublesome to measure the force produce by bracket acting on tooth in clinical, and can’t know the relationship between precise shape of arch-wire and orthodontic force. As for orthodontists, it is useless when they bend arch-wire. Hence, this paper will build the simplified finite element model of arch-wire and bracket, to solve the force that bracket acting on tooth, to create the curve library for the relationship between force and the bending parameter and type of arch-wire.In clinical orthodontic treatment, orthodontists can’t know the reasonable range of orthodontic force in all directions of tooth in advance, so they unable to select the proper parameter and type of arch-wire when they bending arch-wire, direct consequence is that the patients need frequent adjustment. Hence, this paper will base on finite element method, combine the research of clinical root resorption and the relationship between periodontal ligament and tooth movement speed, propose a new method that calculate the reasonable range of orthodontic force in all directions of tooth.Current clinical orthodontic treatment time is so long, and the longer the time is, the more severe the side effects is, hence, it very necessary to reduce the time of clinical treatment. Impose additional vibration load can accelerate tooth movement, yet there has not researcher to studied whether its characteristic parameters are reasonable. Therefore, this paper will base on finite element method, combine the research of clinical root resorption and the relationship between periodontal ligament and tooth movement speed, propose a new method that calculate the reasonable amplitude and frequency of it in all directions of tooth.Based on oral model of this paper, and previous related clinical data, we can preliminary obtain the reasonable range of force in three basic directions of tooth: 0.80~1.30 N for Mistal, 0.90~1.40 N for Lingual, 0.35~0.50 N for Intrusio n. When the basic orthodontic force of Lingual, Distal and Intrusion are 1.25 N, 1.25 N and 0.50 N, respectively, the corresponding directional vibration load are as following: 0.46 N and 1369.5 Hz for Lingual, 0.35 N and 1543 Hz for Mistal, 0.41 N and 193 6 Hz for Intrusion.