Lingual bracket is, generally speaking, short, which sometimes makes it difficult to provide detailed control. While in the Fujita method, tooth axis can be controlled precisely, with maximum utilization of its occlusal slot and horizontal slot. The occlusal slot, which is the main slot, provides precise rotation control and make it possible to place and remove arch wires from occlusal side. The horizontal slot can be used for auxiliary purposes and it provides precise tipping control.
The author will show a case treated with this bracket system. On ligual bracket cases, mandibular molars are not easy to move mesialy compared with labial bracket system so that the case was extracted asymmetrically 3 premolars.

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We investigated “Forces and Moments” and “Forces and Deflections” in ligual orthodontics to distinguish from biomechanics of labial appliance, resulting in making the differences clear between them. In lingual orthodontics, it is not easy to construct and place an properly shaped continuous archwire with loops and springs for maxillary anterior retraction. Nevertheless, frictionless mechanics seems most appropriate for this purpose when a lingual appliance is used. This is due to the reduced interbracket distance resulting in increased friction. In addition, the same amount of distal root torque is thought to generate a greater force on the incisors with a lingual appliance because of the higher load/deflection rate caused by the short interbracket distance. Assuming that the distance between incisor and canine brackets is twice as short with a lingual appliance as with a labial applianece, relationship of the force level required to achieve the the same amount of deflection (m) between the two appliances can be expressed as F=F'X(2I/I)3=8F' (F: lingual appliance, F': labial appliance).
By the same token, the amount of deflection for the same torque requirement is twice as small with a lingual appliance (F'') as with a labial one (F'), which can be represented as F''=FX1/2=8F'X1/2=4F'. According to the cantilever principle, the larger the load/deflection rate, the greater the force derived from the deflection. When a continuous archwire is activated for distal root movement of the incisors the alpha moment exceeds the beta moment to generate a net extrusive force on the incisors. This extrusive force, which is greater with a lingual appliance, does not cause the bite to deepen if the appliance (7th generation Kurz lingual appliance) has bite planes built into the maxillary incisor brackets for the mandibular incisors to occlude against. However, the line of extrusive force passing labial to the center of resistance (CR) of the four maxillary incisors, the extrusive force produces a large amount of mesial root movement of the incisors with the mandibular incisal edges acting as a fulcrum. The M/F ratio decreases along with the mesial root movement, potentially causing uncontrolled tipping of the incisors. We applied an acrylic cap in combination with a high pull J-hook headgear to resist the extrusive force, resulting in a good result.

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Accurate bracket positioning is indispensable in lingual orthodontics in order to attain optimal treatment results. It is, therefore, important to establish labo work procedures, bonding methods, to manipulate ideal arches and to prepare final occlusion setup. In early 70's, Jim Wildman of US first started lingual treatment using labial bracket, followed by lingual bracket development by Cravan Kurz of US and Kin'ya Fujita of Japan in 1976. The author has been trying various methods in the past 20 years of his lingual treatment history. The current system, simplified CLASS with help of TARG will be introduced in this presentation. This can be done in-house laboratory and will provide considerably accurate indirect bonding, which, as a result, will help achieve optimal treatment results.

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Our country has witnessed a rapidly growing interest in malocclusion and an associated increase in demand for orthodontic treatment over the recent decade. With the spread of orthodontic treatment, there has also been an increasing awareness of the need and importance of adult orthodontic treatment.
In adult orthodontics, while lacking in the difficult biological elements that are encountered during orthodontic treatment of growing patients such as growth and developement of the jaws, many different factors must be considered such as harmony with the temporomandibular joints, periodontal conditions, treatment times, stability of treatment results and esthetics. Consequently, orthodontists are often faced with various restrictions and compromises on diagnostic methods, treatment procedures and orthodontic appliances. Higher levels of expertise, diagnostic ability and treatment skill are therefore indispensable for safe reliable adult orthodontic treatment.
In addition to conventional orthodontic analysis and diagnosis, the authors incorporated occlusal diagnosis as part of adult orthodontics by reevaluating mandibular position, occlusal relationship between the maxillary and mandibular teeth, occlusal interferences, etc. during orthodontic treatment. This paper will present an adult orthodontic case with a Class II, Division 1 malocclusion and a deep over-bite successfully treated using lingual and labial appliances in the maxillary and mandibular arches, respectively.

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