Orthodontic composition with polymeric fillers

Abstract

Orthodontic adhesives are claimed which use polymeric filler particles with defined particle size characteristics. The particle size characteristics are controlled such that these adhesives provide comparable mechanical retention and cohesive strength of conventional orthodontic adhesives when used to bond orthodontic appliances to teeth. Because polymeric fillers are generally softer than inorganic fillers, these adhesives are easier to remove from the tooth than conventional adhesives after debonding an orthodontic appliance. Embodiments of the invention include both self-curing and two-part adhesives, packaged adhesive-coated orthodontic appliances, and methods for removing a cured adhesive from a tooth surface.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention broadly pertains to an orthodontic composition. More particularly, this invention pertains to an orthodontic adhesive that contains polymeric fillers.[0003]2. Description of the Related Art[0004]Orthodontic therapy is a specialized type of treatment within the field of dentistry associated with the supervision, guidance and correction of malpositioned teeth into proper locations. Orthodontic treatment can be useful in correcting defects in a patient's bite (also called occlusion) along with promoting better hygiene and improving the overall aesthetics of the teeth.[0005]Orthodontic treatment often involves the use of tiny slotted appliances known as brackets, which are generally affixed to the patient's anterior, cuspid, and bicuspid teeth. After the brackets have been placed on the teeth, an archwire is received into the slot of each bracket and acts as a track to guide the movement of respective ...

AI Technical Summary

Benefits of technology

[0012]There is a need for an improved orthodontic adhesive that offers excellent handling and bond reliability, and also facilitates adhesive removal after the appliances have been debonded from the teeth. The present invention is directed to an orthodontic adhesive which includes polymeric filler particles with defined particle size characteristics. The particle size characteristics are controlled such that these adhesives provide comparable mechanical retention and cohesive strength of conventional orthodontic adhesives when used to bond orthodontic appliances to teeth. However, by virtue of polymeric fillers being softer than most inorganic fillers, these adhesives are generally easier to remove from the tooth surface after debonding of an orthodontic appliance than conventional adhesives.

[0013]Preferably, the adhesive is essentially free of all hard inorganic fillers (i.e. with a Mohs hardness of at least 5). Most conventional adhesives contain quartz filler, or derivatives such as silica glass, which display levels of hardness around 7 on the Mohs hardness scale, compared with a Mohs hardness of 5 for enamel. These values compare to a Mohs hardness of 9 for a fluted tungsten carbide burr, which is commonly used to remove conventional residual adhesive from the tooth after an appliance is debonded. By contrast, the polymeric fillers of the present invention display hardness levels less than 5 on the Mohs hardness scale. Because these materials are comparatively soft, residual adhesive can be removed more thoroughly and easily using a prophy paste or finishing tool such as a scalar or dental finishing disk. By avoiding the need to use a high speed carbide burr for adhesive clean up, the process is shorter and more comfortable to the patient, less heat is generated at the tooth surface and the risk of enamel damage is significantly reduced. Together, the ease of adhesive cleanup, improved patient comfort, and reduced risk of tooth damage provide benefits to both the orthodontist and patient.

Problems solved by technology

It is also possible that one or more appliances may become accidentally debonded when the patient bites down on a hard food substance.

Once hardened, these materials tend to be difficult and time-consuming to remove from the patient's teeth.

Because tungsten carbide is a relatively hard material compared with tooth enamel, there is some risk that the tip will accidentally cause enamel damage, and as a result this removal task is generally carried out by the orthodontist and not delegated to assistants.

Grinding adhesive from the tooth takes a substantial amount of time and it is often cited as one of the most cumbersome procedures, for both orthodontist and patient, of the entire orthodontic treatment.

Furthermore, since the orthodontist's time is very valuable relative to an assistant's time, any procedure only carried out by the orthodontist is inefficient from a financial and / or office management standpoint.

There are also other risks associated with using a high speed rotary hand tool on a patient.

High rotation speeds cause frictional heating of the enamel surface by the fluted burr.

Tooth pulpal damage can occur at these temperatures (Zach et al.

However, removal of residual adhesive containing these fillers still can lead to enamel damage because hardened tools must be used to grind away the residual adhesive.

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