although the invention may be used at the initiation of orthodontic therapy , it is generally directed to subsequent visits during the course of continuing therapy after installation - markers , if originally present , have been removed from the orthodontic appliances . during these subsequent visits , the orthodontist will generally be changing the wires , and / or adjusting the wires and brackets . according to the invention , a coloring agent is applied directly to the orthodontic appliances at the beginning of each visit to help the orthodontist with the visual perception of natural tooth - colored enamel or porcelain brackets and / or other non - contrasting , low visibility orthodontic appliances which may be used currently or in the future , such as natural tooth - colored orthodontic wires . in particular , as shown in fig1 the process helps the orthodontist see the alignment of slot 11 in a bracket 10 , which are used to receive and retain a wire 12 , and to see the bracket tie wings 16 . in addition , the peripheral edges 17 of the bracket are highlighted . natural tooth - colored wires corresponding to the wire 12 are being developed and may be available in the near future . it is anticipated that these natural tooth - colored wires may , like the natural tooth - colored brackets , become very popular with patients . the inventive process herein described may be of even greater assistance to orthodontists when natural tooth - colored wires are used . the method of this invention relies primarily on surface tension between the appliances and the coloring agent to preferentially distribute the colorant to the corners and edges of intersecting surfaces . the surface tension causes the coloring agent to accumulate on level surfaces and to accumulate on bottom surfaces because of adhesive forces . it is believed that higher cohesive forces relative to the adhesive forces cause the colorant to roll off most of the inclined surfaces of the bracket , but that the adhesive forces are sufficient to retain colorant which accumulates at edges and corners where multiple surfaces intersect . in particular , the coloring agent may tend to accumulate within the slot 11 in the bracket and around the peripheral edges 17 where the bracket meets the surface of the tooth . the coloring agent also helps to highlight and visually define other features of the bracket . while the precise phenomena responsive for achieving the results of the invention may not be completely understood , the means for achieving the results are fully disclosed herein . alternatively , if the coloring agent is simply wiped across the brackets and teeth , the coloring agent will accumulate on the front surfaces of the bracket but will not substantially accumulate in the slot 11 , leaving the slot well defined by the absence of coloring . in accordance with the invention , highly adsorptive colorants and prolonged exposure of the colorant to the teeth and the orthodontic appliances should be avoided . after applying the colorant to the orthodontic appliances , the orthodontist should allow the colorant to enter into the corners and edges before making adjustments to the wires . the colorant also helps to identify the elastic bumpers 13 which go around the brackets and hold the wire to the brackets . the coloring agent for use in accordance with the invention should be non - toxic and non - hazardous , and should preferably be a water - soluble , fda - approved food coloring . fda - approved food colorings are preferred because they do not require any additional regulatory approval and are known to be safe for oral use . an important feature of the invention is that the coloring agent should be easily removable . therefore , it is important that the coloring agent be substantially incapable of being absorbed by the teeth and the orthodontic appliances . the coloring agent should preferably be a color such as green or blue to provide greater contrast between the coloring agent and the natural tooth - colored background . while a number of coloring agents have been found to be satisfactory , a readily available blue food coloring comprising f . d .& amp ; c . blue no . 1 , diluted with water and propylene glycol , has been found to be suitable . almost any effective coloring agent is susceptible to some absorption into the teeth and the orthodontic appliances , but such absorption should be minimized as much as possible . it has been found that the advantages of the present invention can be achieved without substantial absorption of the coloring agent into the teeth and the orthodontic appliances . by avoiding absorption , the coloring agent can also be easily removed . using the preferred coloring agent , it has been found that the colorant can be left on the teeth and the orthodontic appliances for approximately five minutes without substantial absorption occurring . a variety of devices may be used to apply the coloring agent to the patient &# 39 ; s teeth and the orthodontic appliances ; however , a single use applicator with a small supply of coloring agent is preferred . one such device is shown in fig2 . an applicator 20 includes a foam rubber swab 22 attached to an enlarged plastic handle 24 by means of a flexible neck 25 . the handle 24 has an internal reservoir 26 containing a small , predetermined quantity of the coloring agent 28 . between the reservoir 26 and the swab 22 is a passage 29 in the neck 25 . the passage 29 has a breakable seal 30 which , when broken , allows the coloring agent 28 to flow from the reservoir 26 to the swab 22 . the seal 30 can be broken by bending or squeezing the flexible neck 25 . a wick ( not shown ) which could extend from the breakable seal 30 to the swab 22 may be used to help direct the coloring agent 28 to the swab . the coloring agent is then applied by dabbing the teeth and the orthodontic appliances with the swab 22 . alternatively , the coloring agent could be applied from a jar or bottle using a small foam brush , perhaps similar to a mascara brush . the coloring agent may be dried onto a foam brush so that the colorant can be used by wetting the brush to release the colorant . another possible alternative is a dispenser in the form of a brush on the end of an eye dropper . the colorant may also be applied using ophthalmic strips such as those manufactured by barnes - hind , inc . under the trademark ful - glo . such ophthalmic strips have a measured amount of coloring agent dried onto a paper strip . the strip is dipped into water and the end of the strip having the colorant on it is applied directly to the orthodontic brackets . because the invention primarily relies on the surface tension of the liquid coloring agent rather than absorption to highlight the edges of brackets , the coloring agent can be easy rinsed off by applying a stream or jet of water into the patient &# 39 ; s mouth after orthodontic adjustments have been completed . occasionally , some brushing such as with a tooth brush may be required to remove the coloring agent completely from the teeth and the brackets . as previously mentioned , the coloring agent should not be left on the teeth and the brackets too long so that substantial absorption does not take place . with the preferred coloring agent , the period of application should be limited to approximately five minutes before removal . while the invention has been shown and described with respect to a particular embodiment thereof , this is for the purpose of illustration rather than limitation , and other variations and modifications of the specific embodiment herein shown and described will be apparent to those skilled in the art . accordingly , the patent is not to be limited in scope and effect to the specific embodiment herein nor in any other way that is inconsistent with the extent to which the progress in the art has been advanced by the invention .
a method for visually highlighting the structural features of orthodontic appliances to facilitate easy discernment of difficult - to - see features , thereby simplifying and reducing the time required for therapeutic readjustment of orthodontic appliances , is disclosed , wherein a contrasting coloring agent is applied directly to the orthodontic appliances to achieve the desired results without any accompanying undesirable effects or disadvantages .