Komori A, Fujisawa M, Iguchi S, Miyashita W

 

Presented in WSLO congress OSAKA 2011,

Nominated as one of the 10 most important lectures in the congress by the chairman Dr. Toru Inami and the scientific committee

 

 

 

Improvements in the customized base design and the bonding system have allowed development of a precise direct bonding system, named KommonBase.

 

KommonBase is characterized by a large bonding base, which can acquire the best fitting and a precise bracket positioning while also enhancing bond strength. There is no need to use transfer trays because of its self-positioning shape.

 

 

 Morphological complexity of lingual surface is a great advantage for applying KommonBase. There are many landmarks on lingual surface of the teeth; cingulum, marginal ridge, linguoincisal edge, lingual groove, etc. KommonBase can achieve seating of bracket position according to the landmarks. Brackets can be positioned easily and accurately by pressing the brackets with explorer. If the bracket is laid on incorrect position, KommonBase can direct it to a correct position.

 

 KommonBase consists of three types of resin; high flow filled flowable resin, low flow filled flowable resin, and high flow unfilled flowable resin. High flow filled flowable resin assures strong bonding property at the interface between bracket base and resin which can penetrate into undercut of bracket base. Low flow filled flowable resin provides a good handling to prevent drift of reference wire and brackets on laboratory procedure. Most part of KommonBase spread over the lingual surface of the teeth consists of high flow unfilled flowable resin. This extended resin was very thin like a film. Even in the case of occlusal interference, interfered resin can be grinded automatically according to the function of occlusion, because high flow unfilled flowable resin is softer than filled resin. For further smart and purposive fabrication, improved resin has been developed.

 

 Trial material demonstrated flexible mechanical property. Flexible character is good for debonding. Bond strength between bracket base and KommonBase was evaluated. Brackets were embedded into acrylic resin with exposure of mesh base. Test material put onto bracket base, and visible light is exposed. Tensile bond strength was measured with cross head speed 1 mm/ min. Trial material showed highest bond strength. This result suggests that less bracket failure was expected with the use of trial material.

 

KommonBase should be bonded firmly throughout orthodontic treatment, and it also should be removed easily without enamel fracture at the end of treatment. Since brackets are bonded closely to gingival tissue, it is difficult to maintain dry field. Although resin adhesive produce strong bond strength, the bond strength of resin adhesive is diminished due to contamination of saliva, which leads to result in bracket failure. Adhesives which do not affected by the presence of water and saliva would clearly be preferred. Hybrid ionomer is superior alternative for the bonding of lingual orthodontic brackets. The bond strength of hybrid ionomer is not affected by contamination of saliva and water.

 

KommonBase can be applied not only to lingual orthodontic brackets but also to other appliances; labial fixed appliance, transpalatal arch, pendulum appliance, lingual arch, etc. Some clinical trials treated with modified appliances were presented in the lecture.