OBJECTIVE. To test the hypothesis that the dimension of the bracket, both in labial and in lingual orthodontics, is a relevant parameter to determinate the forces that act on the teeth, and that some wires commonly used in labial orthodontics (0.016'-diameter SS, TMA and Nitinol) are not suitable for the first phase of lingual treatment.
MATERIALS AND METHODS. An ideal dental cast was bonded with eight different brackets (Damon 3MX, Ovation, Time 2, Innovation and Smart Clip Clarity for the vestibular face; STB, A Denta Time and Innovation-L for the lingual one). After photographic documentation, the interbracket distance was calculated for every type of bracket, using ImageJ software. The mean elasticity modulus of the tested wires was obtained from the review of the available Literature. With mathematic computation the theoretical wire load on every tooth was calculated at three different levels of deflection (0.5 mm; 1.0 mm and 1.5 mm), both on the labial and on the lingual side, for every type of bracket.
RESULTS. Lingual arch in the anterior sector is always shorter than vestibular arch. The different brackets, having different dimensions, have an influence on the interbracket distance, and as a consequence on the wire load. At large deflection, Superelastic NiTi expresses light and continuous forces which are significantly lower than the other examined alloy.
CONCLUSION. The initial hypothesis was supported. Because of the reduced interbracket distance, the adoption of superelastic wires is required in lingual mechanics and with lower diameter compared to labial mechanotherapy, in particular during the first phases of therapy. The use of a bracket with reduced medial-distal dimensions can contribute to reduce the load on the teeth.
KEY WORDS. Interbracket distance, superelasticity, lingual mechanotherapy

View full abstract

In lingual orthodontics, we will receive a limit in a diagnosis and a treatment policy for several cases with an irregular state of a tooth.
Aim: In the case of malocclusion having a peg tooth, it was often that we extracted the peg tooth in substitution for a premolar conventionally and treated. From the treatment result of the cases that we extracted the premolar and performed direct bonding on a upper lateral incisor of the microdont or peg tooth which is seen a lot, I examine stability of occlusion and aesthetic difference.
Methods: I compared these cases about a difference of occlusion, the harmony of the crown width, a parallelism of root.
This time, I will report the resorts of the researches from several cases.

View full abstract

I treated three patients who is Angle class II with lingual appliance and examined the difference of the mechanics of each cases.
[Case 1] Angle class II. #14#24#35#45 extracted.I performed the distal movement of the upper anterior tooth with implant anchors.
[Case 2] Angle II div.1. #14#24 extracted. I performed the distal movement of the upper anterior tooth with class II elastics.
[Case 3] Angle II div.2 #14#24 extracted. Teeth were leveled after aligned with a lingual arch.
The upper anterior teeth were performed torque control at the final stage. As for the upper molar teeth, the maximum anchorage was provided with implant anchor, and Class II elastics. The lower anterior tooth was moved to front side. Having clear treatment target, and introduction of the mechanics is important.

View full abstract

We report the four cases of lingual orthodontics which were treated with asymmetrical extraction of teeth selected by a comprehensive dentistry. The method and treatment plan were changed since the patients had many problems specific to adult orthodontics including tooth defects, periodontal disease and periodontitis. Therefore, the patients required comprehensive treatment. The required comprehensive approach involving multiple clinical departments were as follows: endodontics procedure, periodontal therapy, prosthodontic and orthodontic treatment. Orthodontic treatment has typically been performed only by orthodontist. But these cases suggest the necessity of a comprehensive team approach, which will increase with the increasing rates of adult orthodontic treatment. This changes the orthodontics treatment plan. Lingualists assume important responsibilities in the comprehensive approach to diagnosis and treatment.

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract