Dental agent applicator

An apparatus for applying dental bonding agents to tooth surfaces. The apparatus includes a syringe-type dispenser for holding a quantity of bonding agent and an applicator tip having short bristles at one end. The applicator tip is curved to accommodate access to tooth surfaces undergoing restorative dental procedures. The short bristles are in communication with the syringe-type dispenser, thereby allowing the bonding agent to be continuously applied to the tooth surfaces without the need to stop the procedure and rewet the applicator in a bonding agent source. The syringe-type applicator permits accurate control over the amount of bonding agent applied to the tooth surface. In this way, the tooth surface receives neither an excessive nor an insufficient amount of the bonding agent. Moreover, the short bristles permit the bonding agent to be applied to the tooth surface without damaging the fragile crystalline structure produced during acid etching.

BACKGROUND 
1. The Field of the Invention 
The present invention relates to apparatus for applying dental agents to 
tooth surfaces. More particularly, the present invention allows a dentist 
to quickly and precisely apply a proper quantity of dental agent to tooth 
surfaces which have been prepared to receive the dental agent. The present 
invention is ideally suited for applying dental bonding agents to tooth 
surfaces. 
2. The Prior Art 
Bonding agents play an important role in dental restorative techniques. 
Generally, bonding agents are applied to tooth surfaces in order to firmly 
attach a restoration to the tooth. When the restoration is a composite 
resin restoration, the composition of the bonding agent is usually that of 
the matrix of the composite resin. 
Before applying a bonding agent, the enamel around a cavity preparation is 
etched with acid. Acid etching of enamel creates micro-irregularities on 
the enamel surface. The resin in the bonding agent is usually diluted with 
monomers so that it has a low viscosity which can readily penetrate into 
the microscopic irregularities and undercuts produced by the acid etching. 
The bonding agent is then polymerized. It is believed that when the 
composite restorative resin is inserted into the cavity, it will 
polymerize to the bonding agent present on the cavity surface. In this 
way, better adaptation to the enamel walls of the cavity is achieved with 
improved mechanical retention of the restoration. 
Various devices have been used in the art for applying dental bonding 
agents to tooth surfaces. One device used to apply dental bonding agents 
is a small porous sponge or swabbing material. In practice, a quantity of 
bonding agent is applied to a transfer pad. A sponge is then grasped with 
forceps and dipped into the bonding agent. The wetted sponge is then 
rubbed across the tooth surface in order to apply the bonding agent. 
The small sponges are disposable to prevent cross-contamination. However, 
the sponges do not permit accurate application of the bonding agent. 
Frequently, the bonding agent is applied to surrounding surfaces which do 
not need treatment. Moreover, the rubbing action required to apply the 
bonding agent necessarily damages the fragile crystalline surface 
structure of the tooth formed during acid etching. Once the crystalline 
surface structure of the tooth is damaged, its bondability is reduced. 
Another existing device for applying bonding agent to tooth surfaces is a 
small disposable brush tip. Like the sponge, the brush tip must be held 
with forceps or some other holding device. The brush tip is then dipped 
into a quantity of bonding agent placed on a transfer pad. 
Like the sponge, the brush tip is disposable. In addition, the brush tip 
does not damage the fragile crystalline structure of the tooth surface 
produced by acid etching. However, like the sponge, the brush tip must 
constantly be rewetted by the bonding agent during the dental procedure. 
Moreover, the disposable brush tips used in the art usually have long 
bristles which do not form a fine tip. As a result, the bonding agent is 
often inadvertently applied to surrounding tooth surfaces. 
Yet another device for applying bonding agents to tooth surfaces is a very 
fine paint brush. Such a brush can apply the bonding agent to tooth 
surfaces with precision and detail. 
Despite its advantages, a paint brush must also be repeatedly dipped into a 
quantity of bonding agent during the procedure. In addition, a paint brush 
is difficult to properly sterilize and is usually nondisposable, thereby 
making it difficult for the dentist to maintain an aseptic environment. 
With the ever-increasing threat of Acquired Immune Deficiency Syndrome 
("AIDS") in society, use of a nondisposable applicator which is also 
difficult to sterilize has become unacceptable. 
Further, in each of the known devices for applying bonding agents to tooth 
surfaces, a quantity of bonding agent is placed on a transfer pad so that 
the device can be rewetted during the surgical procedure. Such a technique 
is not only wasteful, but is exposes the bonding agent to light, air, and 
airborne contaminants. 
Moreover, time is often of the essence in applying bonding agents to tooth 
surfaces. As a result, it is important for bonding agents to be applied 
quickly and accurately. Thus, the need to constantly rewet the bonding 
agent applicator during the procedure is not only inefficient, but may 
reduce the effectiveness of the resulting bond between the restoration and 
the tooth surface. 
BRIEF SUMMARY AND OBJECTS OF THE INVENTION 
The present invention seeks to resolve a number of the problems which have 
been experienced in the art, as identified above. More importantly, the 
apparatus of this invention constitutes an important advancement in the 
art of dental bonding agent applicators, as evidenced by the following 
objects and advantages realized by the invention over the prior art. 
One object of the present invention is to provide apparatus and methods of 
applying bonding agents to tooth surfaces which permit continuous 
application of the bonding agent without the need to stop the dental 
procedure and rewet the applicator in a bonding agent source. 
Another important object of the present invention is to provide apparatus 
and methods of applying bonding agents to tooth surfaces which permit 
accurate application of the bonding agent to the precise tooth area that 
needs treatment. 
An additional important object of the present invention is to provide an 
apparatus for applying bonding agents to tooth surfaces which may be 
disinfected and which is disposable, thereby enabling the dentist to 
maintain an aseptic environment. 
Still another object of the present invention is to provide apparatus and 
methods of applying bonding agents to tooth surfaces which permit the 
bonding agent to be applied directly to the teeth from a sterile source 
not exposed to air, light, and airborne contaminants. 
A further important object of the present invention is to provide apparatus 
and methods of applying bonding agents to tooth surfaces which does not 
require the use of a transfer pad. 
Yet another important object of the present invention is to provide 
apparatus and methods of applying bonding agents to tooth surfaces which 
give the dentist greater control over the flow of bonding agent to the 
tooth surface. 
Additional objects and advantages of the invention will be apparent from 
the description which follows, or may be learned by the practice of the 
invention. 
The present invention is directed to an apparatus for applying dental 
bonding agents to tooth surfaces. The apparatus includes a syringe-type 
dispenser for holding a quantity of bonding agent and a removable 
applicator tip having short bristles at one end. The applicator tip is 
curved to accommodate access to tooth surfaces undergoing restorative 
dental procedures. The short bristles are in communication with the 
syringe-type dispenser, thereby allowing the bonding agent to be 
continuously applied to the tooth surfaces without the need to stop the 
dental procedure and rewet the applicator in a bonding agent source. 
The bonding agent remains in a sterile receptacle until applied directly to 
the tooth surface. In this way, the bonding agent is not exposed to light, 
air, and airborne contaminants. In addition, there is no need for a 
transfer pad. 
The syringe-type applicator permits accurate control over the amount of 
bonding agent applied to the tooth surface. Thus, the tooth surface 
receives neither an excessive nor an insufficient amount of the bonding 
agent. Moreover, the short bristles permit the bonding agent to be applied 
to the tooth surface without damaging the fragile crystalline structure 
produced during acid etching.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Reference is now made to the drawings wherein like parts are designated 
with like numerals throughout. Referring first to FIG. 1, one presently 
preferred embodiment of the apparatus of the present invention is 
illustrated and generally designated 10. 
Dental bonding agent applicator 10 includes a syringe barrel 12 and 
applicator tip 14. Syringe barrel 12 is generally cylindrical in shape and 
is adapted for holding a quantity of dental bonding agent 16. 
In the embodiment of the present invention illustrated in FIG. 1, 
applicator tip 14 is removable. Affixed to the lower end of syringe barrel 
12 is a female luer-lock coupling 18. Removable applicator tip 14 is 
secured to syringe barrel 12 through coupling 18. Other means may be used 
to couple the applicator tip to the syringe barrel. For example, a screw 
fit or press-fit coupling mechanism is suitable. 
In another embodiment within the scope of the present invention, applicator 
tip 14 is permanently secured to the syringe barrel. The applicator tip 
may be integrally molded as part of the syringe barrel or it may snap on 
irreversibly to the syringe barrel. In such an embodiment, the syringe 
barrel could be configured to hold only a sufficient quantity of dental 
bonding agent for a single application. Thereafter, the device would be 
discarded. 
Longitudinally slidable within syringe barrel 12 is plunger 20. Plunger 20 
has at its proximal end a thumb disk 22 and at its distal end a plunger 
head 24. Plunger head 24 is constructed out of a resilient material such 
that its outer edge is contiguous with the inner wall of the syringe 
barrel 12. In addition, plunger head 24 is preferably constructed of a 
material which is non-reactive with dental bonding agent 16. 
At the proximal end of syringe barrel 12 are a pair of finger wings 26. 
Although conventional syringes function by placing two fingers on the 
finger wings 26 and depressing thumb disk 22 with the thumb, the present 
invention is preferably used by placing the fingers and thumb around 
syringe barrel 12 and depressing thumb disk 22 by the palm of the hand. 
This unique method of use gives the dentist greater control in applying 
the dental bonding agent. Plunger 20 longitudinally enters syringe barrel 
12. As a result, plunger head 24 presses against bonding agent 16 causing 
the bonding agent to flow out of syringe barrel 12 and through the 
removable applicator tip 14. 
At the distal end of the removable applicator tip are a plurality of 
bristles 28 which form a brush. The bristles are preferably constructed of 
soft fibers which allow the bonding agent to be applied to the tooth 
surfaces without damaging the fragile crystalline structure formed by acid 
etching the surface. Soft nylon is one suitable material for constructing 
the bristles. 
As shown in FIG. 3, the bristles 28 are tightly packed in the distal end of 
the applicator tip 14. The bristles are preferably held in place due to 
friction among the bristles and with the inner wall of applicator tip 14. 
How tight bristles 28 fit within applicator tip 14 is a function of the 
bristle count and bristle diameter. The larger the bristle diameter, the 
fewer bristles will fit within applicator tip 14. The bristles should be 
packed just tight enough to allow dental bonding agent to flow between the 
bristles, but not so loosely that the bristles flow out applicator tip 14 
along with the bonding agent. 
Bristle size affects the flow of bonding agent 16 between packed bristles. 
If the bristles have a large diameter, then voids exist between packed 
bristles through which the bonding agent can flow. On the other hand, if 
the bristles have a small diameter, then very small voids exist between 
the packed bristles significantly limiting the available space through 
which the bonding agent can flow. Thus, the larger the bristles, the 
easier it is to flow bonding agent between packed bristles. In one 
currently preferred embodiment within the scope of the present invention, 
the bristle diameter is in the range from about 0.002 inches to about 
0.005 inches, and preferably in the range from about 0.0025 inches to 
about 0.003 inches. 
In another embodiment within the scope of the present invention, bristles 
28 are held in place by slightly crimping applicator tip 14. In order to 
crimp the applicator tip, it is preferably constructed of a crimpable 
material, such as metal. 
The bristles extend beyond the distal end of applicator tip 14 a distance 
in the range from about 1/16 inch to about 5/16 inch. The bristles extend 
within applicator tip 14 a distance sufficient to engage the inner wall of 
the applicator tip and hold them in place. In one preferred embodiment 
within the scope of the present invention, the bristles extend a distance 
in the range from about 1/4 inch to about 1/2 inch within the applicator 
tip. 
The bristles form a small point at the distal end, thereby permitting 
accurate application of the bonding agent to the tooth surface. In this 
way, the exact quantity of bonding agent may be applied to the precise 
tooth surface that needs treatment and not to surrounding surfaces. The 
removable applicator tip is curved to facilitate application of the 
bonding agent to hard-to-reach tooth surfaces. 
In one embodiment of the present invention, the distance bristles 28 which 
extend beyond the distal end of applicator tip 14 may be manually adjusted 
by the dentist by either pushing the bristles further in or pulling them 
further out. Adjusting the length of the bristles gives the dentist even 
greater control in applying the dental bonding agent. By pushing the 
bristles further within applicator tip 14, the dentist has more pinpoint 
control in applying the bonding agent. By pulling the bristles further out 
from the applicator tip, the dentist can cause the bristles to fan out and 
accurately coat a larger tooth surface. 
In addition, FIG. 3 illustrates a male luer-lock fitting 30 on the 
applicator tip. The male luer-lock fitting is designed to engage female 
luer-lock coupling 18. Should coupling 18 be constructed in a press-fit or 
screw-fit embodiment, then fitting 30 should be a corresponding press-fit 
or screw-fit embodiment so that the applicator tip may be removably 
attached to syringe barrel 12. 
As illustrated in FIG. 2, the applicator tip may be removed and replaced 
with a cap 32. In one embodiment of the invention, the syringe barrel may 
be marketed pre-filled with bonding agent and capped with cap 32. 
Alternatively, the syringe barrel 12 may be filled with bonding agent by 
removing cap 32 and drawing the desired amount into the barrel. 
In use, cap 32 is removed and replaced with applicator tip 14. After the 
bonding agent is applied to the tooth surface, the applicator tip is 
removed and discarded. Cap 32 is then replaced, and the syringe barrel is 
stored until bonding agent is needed in the future. If used properly, the 
syringe barrel should still be clean; nevertheless, the syringe barrel may 
be disinfected, if necessary. 
Bonding agent applicator 10 is constructed of easy to disinfect materials. 
The syringe barrel, plunger, coupling, and applicator tip are preferably 
constructed of rigid plastic, though other suitable construction materials 
such as glass or metal may be used. It is also important that the syringe 
barrel, plunger, coupling, and applicator tip be constructed of a material 
which will not react with dental bonding agent 16. In addition, the 
bonding agent should not adhere to the construction material. 
Because bonding agents are often light sensitive, the bonding agent 
applicator is generally constructed of an opaque material. Thus, the 
syringe barrel, applicator tip, plunger, and coupling are preferably 
constructed of black plastic. Different colored plastic may be used to 
identify the type of bonding agent within the syringe barrel. 
Alternatively, printing or other identifying markings on the syringe 
barrel may be used to identify the type of bonding agent. In addition, 
markings on the outer surface of the syringe barrel or plunger may be used 
to identify the volume of bonding agent used or remaining. 
The plunger within the syringe barrel permits controlled dispensing of the 
bonding agent to the tooth surface. It will be appreciated that other 
means may be used to control the dispensing of the bonding agent. For 
example, the bonding agent applicator may be adapted for capsule use or 
for squeeze-bulb use. 
Although the above discussion has described an apparatus for applying 
dental bonding agents to tooth surfaces, it will be appreciated that the 
apparatus may be adapted for applying other dental agents to tooth 
surfaces. Other dental agents, such as dentin sealants, for example, need 
to be precisely applied to specific tooth surfaces in a very thin layer. 
Suitable dental agents should preferably have a viscosity low enough to 
flow through the small spaces between bristles 28, but not so low that the 
dental agent runs freely out the apparatus. In such cases, the apparatus 
within the scope of the present invention may be advantageously used to 
apply other dental agents. Thus, the foregoing discussion regarding 
bonding agents is equally applicable to other similar dental agents. 
From the foregoing, it will be appreciated that the present invention 
provides apparatus and methods for applying bonding agents to tooth 
surfaces which permit continuous application of the bonding agent without 
the need to stop the dental procedure and rewet the applicator in a 
bonding agent source. 
Additionally, it will be appreciated that the present invention further 
provides apparatus and methods for applying bonding agents to tooth 
surfaces which permit accurate application of the bonding agent to the 
precise tooth area that needs treatment. 
Likewise, it will be appreciated that the present invention provides an 
apparatus for applying bonding agents to tooth surfaces which may be 
disinfected and which is disposable, thereby enabling the dentist to 
maintain an aseptic environment. 
In addition, it will be appreciated that the present invention provides 
apparatus and methods for applying bonding agents to tooth surfaces which 
permit the bonding agent to be applied directly to the teeth from a 
sterile source not exposed to air, light, and airborne contaminants. As a 
result, the present invention does not require the use of a transfer pad. 
It will also be appreciated that the present invention provides apparatus 
and methods of applying bonding agents to tooth surfaces which give the 
dentist greater control over the flow of bonding agent to the tooth 
surface. In this way, a proper amount of bonding agent is applied to the 
tooth surface, not an excessive or insufficient amount. 
The present invention may be embodied in other specific forms without 
departing from its spirit or essential characteristics. The described 
embodiments are to be considered in all respects only as illustrative and 
not restrictive. The scope of the invention is, therefore, indicated by 
the appended claims rather than by the foregoing description. All changes 
which come within the meaning and range of equivalency of the claims are 
to be embraced within their scope.