GB2437950A

GB2437950A - Dental device and method

Info

Publication number: GB2437950A
Application number: GB0610028A
Authority: GB
Inventors: Nicholas Keith Amery
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-05-19
Filing date: 2006-05-19
Publication date: 2007-11-14
Also published as: GB0610028D0

Abstract

A dispenser 2 for dispensing dental fluid (5) and a method of dispensing dental fluid. The dispenser 2 comprises a reservoir 4 and a pump mechanism 6. The pump mechanism 6 comprises a nozzle 8, 12. In use, a predetermined amount of dental fluid (5), for example such as light curable adhesive resin or other bonding agent or other dental chemical, is dispensable from the nozzle 8, 12 by actuation of the pump mechanism 6. Preferably the nozzle 12 is disposed remotely from the pump mechanism 6 by an elongate tube 10 that may be flexible thus allowing the distal nozzle 12 to be positioned as desired.

Description

Dental Device and Method The present invention relates to a device for

use in dentistry and a method of using the device. In particular, the present invention relates to a device and method for dispensing fluid substances or materials used in the practice of dentistry.

When a tooth is miscoloured, misshapen, damaged, or has other flaws, it is desirable to correct the flaws by sealing the tooth, filling gaps in the tooth, providing a crown and/or treating the tooth in any other suitable manner. As is known in the art, repairing or restoring a tooth, particularly a direct restoration such as providing a filling, veneer or the like, requires considerable preparation and involves many time-consuming and expensive steps. First the tooth must be prepared, by removing decayed, damaged or other undesirable parts of the tooth enamel, which is usually carried out by drilling or polishing. The tooth or remaining cavity is then etched using an etching chemical to provide a pitted or rough surface. A bonding agent or adhesive resin is applied to the etched tooth surface. To ensure even coverage of the surface, the agent or resin is distributed using a device that provides puffs of air.

The thin layer of agent or resin is then cured so that it hardens. Generally further layers are required after the first layer, in order that the tooth may be then restored using increments of filling material, and so the process is repeated until the restoration is of a desired shape or size, to restore' function and aesthetics in any given case. If an indirect restoration is to be provided, the tooth may also need to be prepared in a similar manner and further provided with a suitable adhesive such as dental cement for fixing the restoration in place.

It is important when applying any of the above chemicals to the tooth that a predetermined amount of the chemical be applied as a thin and even layer. For example, when applying the etching chemical, it is necessary to apply an amount sufficient to etch the tooth surface. Or when applying an adhesive it is important to ensure that sufficient adhesive is provided to wet' (grip) the tooth and any restoration applied to the adhesive, but excessive amounts of adhesive can result in a build up of the adhesive that may compromise the strength of the adhesion achievable. Or when applying composite resin, it is necessary to apply sufficient resin to build up an even coating over the tooth, but too much resin may result in only the outer portion of the resin being fully hardened when the resin is light cured and thus the inner portion of the resin may remain soft and prone to damage.

In order to provide layers of resin, adhesive, etching chemical or the like that are of a desirable thickness and are evenly applied across the tooth, it is known to apply the chemical using a specially designed brush. The chemical for application to the tooth is poured into a small cup or tub, into which the brush is dipped to coat the bristles. The brush must be disposable, because the chemicals can be caustic and damage the brush bristles, or the chemicals can dry out, adhering the bristles together, and generally it is more hygienic to dispose of the brushes than to reuse them as they are difficult to thoroughly clean. However, using disposable brushes is expensive and wasteful. Furthermore, when applying many layers of the chemicals to a tooth, the brush must be repeatedly dipped into the cup containing the chemical, resulting in repetition of hand movement, increasing complexity of procedure, and time required to carry out task, which when multiplied over a days workload, contributes to significant expense of energy. Furthermore, the chemicals used in dental treatments are generally volatile, toxic and sensitive to light and air. It is therefore desirable to store the chemicals in storage bottles, from which the chemical must be poured prior to use. Once the chemical has come into contact with the air and has been subjected to light, or contaminated by oral fluids, it cannot be returned to the storage bottle and so any of the chemical that is poured out but not used must be disposed of safely. Therefore it is inevitable that some of the chemical will be wasted.

As mentioned above, when applying the chemical to a tooth, it is necessary to repeatedly dip the brush into the cup holding the chemical and to apply the chemical to the tooth. Therefore, not only is this method of application time consuming, but there may be an increased risk of contamination each time the brush is introduced to the patient's mouth. Furthermore the chemicals are generally toxic and the practitioner applying the chemical is subjected to such toxicity throughout application of the chemical and therefore it is desirable to minimise the time spent applying the chemical, or exposed to such volatile chemicals in any instance, by patient or operator. Also, although preventative measures such as wearing gloves are taken to prevent contact with the chemicals, it is likely that after a period of exposure to the chemicals even the preventative measures will not be sufficient to effectively protect the practitioner from the chemical. For example, latex gloves can be penetrated by some dental chemicals leading to allergies and chemical toxic effects. Therefore it is clearly desirable to minimise the length of time during which the chemicals are used in preparing and treating a tooth.

Furthermore, such dental fluids and the like are expensive and when estimating the cost of a treatment, with prior art methods and products it is difficult to determine what amount of fluid will be used and how much will be wasted.

In light of the above problems, the applicant has realised that there remains a need for a device and a method for applying chemicals used in dental preparation and treatment, that can repeatedly provide measured doses of the chemical in a quick, convenient and reliable maimer and that disperses the chemical evenly and with a desired thickness to a surface or the like to be treated, for example to a tooth surface or cavity.

In accordance with a first broad aspect of the present invention, there is provided a dispenser for dispensing dental fluid, the dispenser comprising a reservoir, a pump mechanism, and a first nozzle fluidly connected with the reservoir by the pump mechanism, wherein, in use, a predetermined amount of dental fluid is dispensable from the nozzle by actuation of the pump mechanism.

The present invention therefore provides a device that can dispense, in a single action, a metered dose of a dental fluid, which may for example be chemical etchant, adhesive resin, chemical resin, composite resin, primer agent, disclosing agent, fissure sealant or any other fluid used in dental preparation or treatment or the like. In its particularly preferred embodiments, the device is configured such that the amount of dental fluid dispensed is appropriate in relation to the chemical contained in the reservoir, and preferably also the nozzle is configured such that an even and diffuse spray of the chemical is provided to the surface being treated, such that a layer of the chemical is provided on the surface that is of a desired thickness and is also evenly spread across a part of or the entire surface. This is particularly advantageous because a single spray may be all that is necessary to coat the tooth with the desired amount of chemical and, since an even coating can be applied, it is not necessary to use air puffs to disperse the fluid. Furthermore, using only a single spray means that it is not necessary to repeatedly introduce the device into a patient's mouth, thus reducing the risk of contamination of the device and transmission of contaminants to the patient, and also significantly reducing the time taken to perform the task. Still further, as the chemical is contained in the reservoir until it is dispensed from the nozzle, exposure of the patient and the practitioner to the chemical is minimised and also the risk of the chemical contacting the practitioner and penetrating any protective clothing is also minimised. By having a controlled amount dispensed each time the dispenser is actuated, it is possible to measure consumption of such materials to a degree that is not currently possible. Still further, having a single unit to per!brm the above steps reduces the amount of instruments required by the practitioner thereby providing further storage and cost benefits.

The nozzle of the device may be directly connected to the reservoir and may, for example, be integrally formed with the pump mechanism such that the nozzle is in relatively close proximity to the reservoir. This provides a device that is controllable and easy to direct towards the surface to be treated. However, although such an arrangement is useful for applying dental fluid to, for example, teeth at the front of the mouth, it may be difficult to accurately apply the fluid to teeth further back along the jaw or in other awkward to reach locations. Preferably therefore the dispenser further comprises a tube fluidly connected with the first nozzle such that, in use, the predetermined amount of dental fluid is dispensed from the tube. This is advantageous because the desired metered dose can be dispensed via the tube and thus, for example, a tooth further back and even at the rear of the jaw can be treated.

Furthermore, the distance between the practitioner and the point at which the fluid is dispensed is increased, thereby further reducing exposure of the practitioner to the chemical. In a particularly preferred embodiment, the tube is removably attached to the nozzle. Should the tube become occluded, or irreversibly contaminated in the mouth, a new replacement can be attached to permit continued use of the device until its reservoir is exhausted.. Furthermore, having a tube that is removable means that the tube can be cleaned, or can be disposed of after treatment if desired for hygiene purposes or if the fluid has built up and is partially blocking the tube. A new tube can then simply be connected to the device prior to the next treatment. For example, when providing the dispenser, it may be advantageous to supply a number of, say, five tube attachments with a pump mechanism and reservoir, thus allowing the tubes to be re-used but replaced if, say, a blockage occurs, i.e. to have semi-disposable tubes.

In a further embodiment of the invention, the tube is directly connected to the pump mechanism and the nozzle is proved at the end of the tube distal from the pump mechanism. Namely the tube is effectively an extension of the pump mechanism, and the nozzle can be integrally formed with the tube. This arrangement is advantageous because the nozzle may be capable of dispersing the fluid in a more even layer than might be achieved by dispersing the fluid directly via the tube.

In a particularly preferred embodiment of the present invention, in which the dispenser has a first nozzle associated with the pump mechanism and a tube, the dispenser further comprises a second nozzle, fluidly connected to tube at the end thereof distal from the first nozzle such that, in use, the predetermined amount of dental fluid is dispensed from the second nozzle. This is a particularly advantageous arrangement because the fluid is passed and/or dispersed evenly into the tube via the first nozzle and then passes along the tube and is dispersed under pressure and at a further predetermined velocity via the second nozzle to the surface to be treated.

Therefore a dispenser is provided that is highly controllable with regard to the dispersed amount of fluid and with regard to the angle and pattern of dispersement of the fluid, thus providing a device that is capable of reliably coating a surface with a regular, even and desired thickness layer of fluid. Alternatively, in a preferred arrangement, the second nozzle provides the spray function and the tube attaches to the pump directly via the first nozzle, and represents an extension of the reservoir volume of fluid, analogous to a dead space, where the volume of which becomes active only when pressure is exerted by the pump mechanism.

The second nozzle may be fixed in position relative to the tube and/or relative to the first nozzle and/or relative to the reservoir. Additionally or alternatively, the tube may be fixed in position relative to the first nozzle andlor relative to the reservoir. I lowever, mechanical pumps generally function optimally when the reservoir is in a specific position relative to the pump mechanism, which is usually when the pump mechanism is arranged generally above the reservoir such that fluid can be drawn up from the reservoir by actuation of the pump mechanism and dispensed from the dispenser. Whilst this position may be optimised for dispensing dental fluid to, say, the teeth of a patient's lower jaw, in order to dispense dental fluid to the upper jaw, the dispenser must be inverted, thereby positioning the reservoir above the nozzle, which may adversely affect the ability of the dispenser to dispense fluid evenly and at a predetermined level. Therefore in a preferred embodiment of the present invention, the first nozzle andlor the second nozzle is rotatable and/or repositionable relative to the reservoir. This is particularly advantageous because the second nozzle can therefore be positioned such that fluid is dispensed in the desired direction without affecting operation of the pump mechanism or the level and distribution of the dispensed fluid. When referring to the nozzles being rotatable and/or repositionable relative to the reservoir, this can be achieved by any one or more of the following arrangements. The first nozzle can be rotatable andlor repositionable relative to the reservoir. In this arrangement, the second nozzle and the tube can be fixed relative to each other and to the first nozzle, and by rotation and/or repositioning of the first nozzle relative to the reservoir, the second nozzle will consequently be rotated and/or repositioned relative to the reservoir. The tube can be rotatable and/or repositionable relative to the first nozzle.

In this arrangement, even if the second nozzle is fixed in position relative to the tube, and the first nozzle is fixed relative to the reservoir, by rotating or repositioning the tube relative to the first nozzle and thus relative to the reservoir, the second nozzle at the end of the tube is rotated and/or repositioned relative to the reservoir. The second nozzle can be rotatable and/or repositionable relative to the tube. In this arrangement, even if all the other components are fixed in position relative to the reservoir, the second nozzle can be rotated and/or repositioned such that fluid can be dispensed at whatever position or angle is desired.

Whilst it is advantageous to be able to reposition and/or rotate the nozzles or tube to dispense fluid in the desired direction, in some instances it may still be difficult to achieve an even coating of dental fluid on a desired surface. For example, when trying to apply dental fluid to, say, the outer surface of a wisdom -.7-tooth (or indeed any other difficult to reach surface) even rotating or repositioning the nozzle or tube may be insufficient to overcome obstacles to reaching the tooth and positioning the nozzle near to the surface to be coated. Therefore in a preferred embodiment, at least a part of the tube of the dispenser is flexible. In a particularly preferred embodiment, substantially the entirety of the tube is flexible. This is advantageous because having a flexible tube allows the end of the tube, or the second nozzle at the end of the tube, to be placed precisely relative to the surface to be treated, even when obstacles in the area around the surface would otherwise prevent a substantially straight tube from reaching the surface, since the tube can be bent around, over or under any such obstacle. The ability to reach a desired surface is further enhanced when the flexible tube is combined with a rotatable or repositionable nozzle or tube as disclosed above. It is particularly preferred that the partially or wholly flexible tube is formed of a material that is capable of being bent into a desired shape and that will remain in that shape until bent into a different position, i.e. that the material comprising the tube is delbrmable and has shape memory.

Whilst some or all of the components of the dispenser can be integrally formed, it is preferable that at least one of the first and second nozzles is removable from the pump mechanism and/or from the tube. Therefore the nozzle or nozzles can be removed as desired for cleaning, to avoid build up of dental fluid occurring, or for replacement if desired, for example for hygiene purposes. Furthermore, having removable nozzles allows nozzles having different dispersal patterns and/or angles to be used interchangeably, which is particularly advantageous for dental use because it may be desired to have a smaller area of dispersal when, for example, treating smaller teeth (such as children's' teeth or teeth at the front of the jaw) and to have a larger area of dispersal when, for example, treating larger teeth (such as adult teeth or teeth to the rear of the jaw). Namely an appropriate nozzle can be chosen depending on the desired size and density of spray pattern. Furthermore, having interchangeable nozzles allows the dispenser to be customised based upon the properties of the fluid in the reservoir, for example based upon the viscosity of the particular fluid in the reservoir.

The dispenser according to the various embodiments of the present invention is generally intended for multiple applications of dental fluid, rather than for disposal after each application or set of applications. Therefore it is preferable that the dental fluid in the reservoir can be stored for prolonged periods of time. Whilst the components of the dispenser can be made from any suitable material such as plastic, glass, metal, or the like or any combination thereof, many dental fluids arc volatile and are sensitive to light and therefore, whatever material the components comprise, it is preferable that at least one of the reservoir and the pump mechanism is opaque. Most preferably, the reservoir and the pump mechanism are both opaque and preferably also any additional components, such as the tube and the second nozzle etc., are also at least partially and preferably wholly opaque. Having opaque components is advantageous because the light sensitive contents of the reservoir are protected and thus maintained in their desired fluid form without any significant degree of polymerisation occurring even in the presence of ambient light or light from any other source where the dispenser is used or stored. In order to further protect the fluid used in the dispenser from ambient or other light sources, in a preferred embodiment the dispenser further comprises a sheath or sleeve for at least partially surrounding one or more of the components of the dispenser. In a particularly preferred embodiment, the sleeve at least partially, and preferably substantially entirely, encases the tube of the dispenser, and furthermore preferably a sleeve is provided for the reservoir of the dispenser or any other component of the dispenser. Such sleeves are preferably designed to be at least partially or preferably entirely opaque to the wavelengths of light that affect the particular dental fluid stored in the dispenser and therefore sleeves of different compositions and levels and types of opacity can be selected depending on the contents of the dispenser. The sleeve serves to protect the vulnerable spray component on the nozzle from light penetration, when chemical in use is vulnerable to this ambient light. It can be pulled or removed back prior to use exposing the spray nozzle, while in storage it is re-sheathed to coved the nozzle and prevent evaporation/polymerisation of nozzle contents.

Furthermore, it is preferable for the dispenser to be atmospherically sealed, for example in a preferred embodiment the pump mechanism is sealed to the reservoir in a substantially airtight manner, thereby reducing or eliminating evaporation of the fluid in the reservoir. This prevents fluid evaporating from the dispenser during storage, thereby providing a dispenser with a longer shelf life and that is more efficient in that substantially the entire contents of the dispenser can be used for treating teeth or the like. Additionally or alternatively it is preferable that other components of the dispenser are sealed in a substantially airtight manner. For example, the seal between the tube and one or both of the nozzles is preferably airtight. Still further, in order to render the dispenser substantially airtight during storage, i is preferable that the dispenser further comprises at least one cap that is capable of covering the nozzle and/or the end of the tube and/or the entire tube in a substantially airtight manner, thus preventing air entering the tube or nozzle and causing the fluid in the tube or nozzle to evaporate or dry out during storage.

Preferably the cap is opaque, thus minimising the effect of ambient or other light on the fluid which may reside in the nozzle and/or in the tube between uses of the dispenser. Having a cap at the dispensing end of the dispenser is also advantageous in that it helps to prevent any of the dental fluid leaking from the dispenser during storage, which is particularly desirable since as mentioned above, many of the chemicals used in dentistry are volatile and/or toxic and therefore any leakage may be potentially harmful to the environment and/or to the practitioner storing or using the dispenser.

The predetermined amount of dental fluid may be dispensed from the dispenser as a narrow jet of fluid. This arrangement is typically useful for applying the fluid in a small area on a surface. Preferably, however, the dental fluid will be dispensed as a diffuse spray over a desired area such that an even and thin layer of fluid is applied to the surface to be treated, and therefore the surface is readily wetted. This is particularly advantageous when dispensing dental fluid to a tooth, since in order for the fluid to be suitable for its purpose it is often desirable for the fluid to rapidly flow out across the tooth surface to form a thin film that is of a precise thickness. By wetting the tooth surface evenly it is not necessary to disperse the applied fluid using puffs of air, as is usually required in the art, and thus the time taken for each treatment is reduced according to the present invention, thus reducing the length of time the practitioner and patient are exposed to the dental chemicals.

Furthermore having an even spray of fluid, which can be optimised to the specific -10-viscosity of the fluid by configuring the nozzle accordingly, as discussed below, may accelerate the wetting of the prepared tooth (of the enamel or of the dentine) and the penetration of the fluid into, for example, collagen fibres or other tissue present in the dentine, thereby further reducing the treatment time and reducing bonding errors that may occur with air distributed fluids.

In a particularly preferred embodiment of the present invention, at least one of the first and second nozzles comprises a first chamber for receiving fluid from the reservoir, the first chamber having a first fluid exit, a second chamber, fluidly connected to the first chamber by the first fluid exit and further having a second fluid exit, and obstructing means for partially obstructing flow of dental fluid in the second chamber between the first fluid exit and the second fluid exit, such that, in use, dental fluid is diffusely dispersed from the second fluid exit. This arrangement is advantageous because the nozzle is suited for providing a fine, diffuse and even spread of fluid onto the surface being treated and can be tailored to the properties of the fluid, such as the specific viscosity of the fluid or the like. Furthermore the nozzle or nozzles are relatively simple to construct, easy to clean and inexpensive, should it be desirable for the nozzle to be disposable. Furthermore, such an arrangement can be integrally formed with the tube or can alternatively be independently formed and provided in a removably attachable manner for removal for cleaning or replacement, and still further can be rotatable relative to the tube or pump mechanism or the like.

The obstructing means can be any suitable means that inhibits the flow of the fluid such that the fluid exits the second fluid exit under greater pressure and at a velocity greater than the fluid entering the second chamber. In a preferred embodiment, the obstructing means comprise a planar member aligned between the first fluid exit and the second fluid exit and that is substantially perpendicular to the direction of fluid flow, such that, in use, dental fluid in the second chamber passes over around the planar member to be dispensed from the second fluid exit. This is advantageous because inhibiting the flow of fluid in this manner increases the velocity of the fluid exiting the second fluid exit due to increased pressure within the nozzle. This provides a spray that is dispersed finely at a relatively wide range of angles, rather than being dispersed as a narrow jet. The fluid velocity and pressure can additionally or alternatively be increased by having a preferred arrangement of the nozzle in which the first fluid exit comprises a first opening in the first chamber, and the second fluid exit comprises a second opening in the second chamber, the first opening being larger than the second opening. Thus as the fluid is forced through the narrower second opening under pressure, the velocity of the fluid exiting the opening is relatively high. Furthermore, the flow of fluid can additionally or alternatively be inhibited or altered by providing means at or near any one or more of the fluid exits. For example, in a preferred embodiment the second chamber further comprises at least one baffle at the second fluid exit to further impede fluid flow. A baffle or other suitable means could also or alternatively be provided elsewhere in the dispenser for further impeding fluid flow and thus increasing the pressure of the fluid and thus the velocity and dispersal of the fluid dispensed from the dispenser, and/or for directing the flow of fluid in a desired direction. The dispenser of the present invention can comprise any suitable dispenser. For example a gas or other propellant activated pump could be used. However, as it is desired to dispense predetermined, individual sprays of the fluid in a diffuse and controlled spray, it is particularly preferred that the pump mechanism is a mechanical pump which comprises a dip tube, means for securing the pump to the reservoir, and resilient means for biasing the pump into a first position. The reservoir comprises an opening for receiving the dip lube, and when the dip tube is received in the reservoir and the pump is secured to the reservoir, actuation of the pump compresses the resilient means thereby moving the pump into a second position and dispensing a predetermined amount of dental fluid. As mentioned previously, it is preferable that the pump mechanism and the reservoir are secured together in a substantially airtight manner, for example it is preferable that a substantially airtight seal is provided between the pump mechanism and the reservoir if the components are provided as separate parts.

Whilst the above dispenser is suitable for dispensing a dental fluid, it is often desirable to dispense more than one type of fluid in a particularly treatment.

Although the pump can be adjusted to be suitable for dispensing different fluids as discussed above, it is not convenient to do so during treatment, particularly if the chemicals concerned are incompatible or react when in contact with each other.

-12 -Therefore in a preferred embodiment of the present invention there is provided a dispenser as disclosed above and further comprising at leasta second reservoir and a second pump mechanism, wherein, in use, a predetermined amount of a further dental fluid is dispensable from the second pump mechanism independently of dental fluid dispensable from the first pump mechanism. Further additional reservoirs and pump mechanisms can also be provided as desired. This is a particularly advantageous arrangement because it is often desirable to apply two or more different fluids to the same area being treated and having two or more actuatable pumping mechanisms that are aligned relative to each other and can independently dispense different fluids means that, say, a tooth can be treated rapidly and without the need to remove the dispenser from the patient's mouth, thus eliminating the need to introduce to the mouth and to line up a second or further dispenser for applying the second or further fluid. Thus more accurate placement of the additional fluids can be achieved and also the additional fluids can be applied very quickly after application of the initial fluid, which may be important when the fluids are volatile, or could evaporate, or are chemically altered by exposure to air or moisture. In a particularly preferred embodiment, the first reservoir and at least the second reservoir are integrally formed and comprise separate compartments of a single container, each compartment having an opening for receiving a dip tube of the corresponding pump mechanism. The various embodiments having at least a second reservoir and pump mechanism are particularly suited for dispensing complimentary dental fluids, such as primer and bonding agents for example.

The above features of the embodiments of the first broad aspect of the present invention can be combined in any suitable and compatible maimer and arc not exclusive features that are only used in isolation. Furthermore, each or any of the above features or functions, whilst described in relation to a dispenser device, are also applicable, where appropriate, to a second broad aspect of the present invention, in which there is provided a method of dispensing a predetermined amount of a dental fluid, the method comprising the steps of providing a reservoir containing a first dental fluid, providing pumping means for pumping the first dental fluid from the reservoir to a nozzle, and actuating the pumping means to dispense a predetermined amount of dental fluid from the nozzle. Therefore there is provided -13 -an advantageous method of applying an even, thin and diffusely dispersed coating of dental fluid to, for example, a tooth, that reduces the time taken to apply such fluids by eliminating the time consuming and expensive steps of applying small amounts of fluid with a disposable brush from a disposable cup containing the fluid, and dispersing the fluid using puffs of' air. Wetting of the enamel and/or dentine is accelerated and a precise and even layer is provided. Preferably the pumping means comprises a mechanical pump and said step of actuating the pumping means comprises depressing the pumping means towards the reservoir a predetermined distance and releasing the pumping means after the predetermined amount of dental fluid has been dispensed. Thus a dispenser that can easily be activated, for example by depressing the top of the dispenser with a thumb or linger, is provided.

Certain preferred embodiments of the present invention will now be described, by way of example only, and with reference to the accompanying drawings, in which: Figure 1 shows a dispenser in accordance with an embodiment of the present invention having a downwardly dispensing nozzle; Figure 2 shows a dispenser in accordance with an embodiment of the present invention having an upwardly dispensing nozzle; Figure 3 shows a dispenser in accordance with an embodiment of the present invention in its actuated position for dispensing fluid; and Figure 4 shows various nozzle arrangements in accordance with embodiments of the present invention.

Referring to Figure 1, there is shown a dispenser 2 in accordance with a preferred embodiment of the present invention. Preferably the dispenser 2 and its components comprise a suitable material that is resistant to damage from the chemical to be stored and dispensed therefrom. The dispenser 2 of this embodiment comprises a reservoir 4 and a pump mechanism 6. The pump mechanism 6 has several components in this embodiment or has several components attached thereto.

Generally the dispenser 2 further comprises a first nozzle 8, which as shown in this figure can simply comprise the part of a tube 10 that passes into the pump mechanism 6 and allows fluid stored in the reservoir 4 to flow into the tube, or in other embodiments the nozzle 8 can comprise a slit, hole or other opening in a part -14 -of the pump mechanism 6 that fluidly coimects with the tube 10. If the slit, hole or other opening is smaller than the size of the tube 10, then the increased pressure of the fluid being forced through the smaller opening increases the velocity of the fluid and/or at least partially alters the direction of fluid flow as it is pumped through the nozzle 8 and along the tube 10.

The dispenser 2 further comprises an elongate straw or tube 10, as previously mentioned, that is suitable for directing fluid to a desired position. The tube 10 can be flexible to allow it to be deformed or flexed as desired. At one end of the tube 10 distal from the nozzle 8 there is provided a further or second nozzle 12 for dispensing fluid pumped from the reservoir 4 by the pump mechanism 6 and along the tube 10. The pump mechanism 6 comprises means 14 for actuating the pump mechanism 6 and a dip tube 16. In this embodiment, the means for actuating the pump mechanism or actuator 14 comprises a portion of the pumping mechanism 6 that is moveable relative to the dip tube 16 and the reservoir 4. For example in this embodiment, the actuator 14 is depressible toward the reservoir 4. The pump mechanism 6 further comprises a collar 18, which co-operates with a neck portion of the reservoir 4, for example in a preferred embodiment the collar 18 has a screw thread on the inside thereof and the neck portion 20 has a co-operating screw thread on the outside thereof such that the collar 18 can be screwed to the neck portion 20. Preferably a seal, such as a rubber or other material 0-ring or the like (not shown), is provided between the collar 18 and the neck portion 20 of the reservoir 4 to provide a substantially airtight seal. The collar 18 in this embodiment comprises a receiving portion 22 for receiving the lower portion 26 of the actuator 14 in slidable engagement therewith, such that the lower portion 26 of the actuator 14 is gripped in the receiving portion 22 of the collar 18 but can move relative to the receiving portion 22. In this embodiment, the collar 18 further comprises connecting means 24 that connect the dip tube 16 to the collar 18 and therefore fix the dip tube 16 relative to the reservoir 4 when the collar 1 8 is secured to the neck portion 20 of the reservoir 4.

The actuator 14 further comprises gripping means 32 in this embodiment, which comprise a generally cylindrical section that grippingly engages the upper end of depressing means 28 arranged coaxially with, and generally beneath, the gripping -15 -means 32. Between a lower end of the depressing means 28 and an upper end of the dip tube 16 there is provided a resilient means 30, which in this embodiment comprises a spring 30.

Figure 4 shows various embodiments of the nozzle 12 that can be provided at the distal end of tube 10 of a dispenser 2 in accordance with the present invention, and an embodiment of which is shown in figure 1. Furthermore, the nozzle 8 provided at the other end of the tube 10 fluidly interposed between the dip tube 16 and the dispensing tube 10 may also be of a similar construction to the nozzle 12 shown in figures 4(a) to (d). In the first embodiment of figure 4, the nozzle 12 comprises at least two chambers, which in this embodiment are divided into upper or first chamber 42 and lower or second chamber 44. The chambers 42, 44 are separated by a divider 41 having an opening or first fluid exit 46 via which fluid can pass from the upper chamber 42 to the lower chamber 44. In this embodiment, the nozzle 12 is integrally formed with tube 10 and so tube 10 forms upper chamber 42 and at least part of divider 41. The lower chamber 44, which is fluidly connected to the upper chamber 42 by the first fluid exit 46, can be integrally formed with the tube 10 or can be attached to the tube 10 or to the upper chamber 42 in any suitable maimer. The lower chamber 44 has an opening or second fluid exit 48 that, in this embodiment, is smaller (i.e. if the openings 46, 48 are generally round holes, has a smaller diameter) than the first fluid exit 46. Between the first fluid exit 46 and the second fluid exit 48 the nozzle 12 comprises obstructing means 40 which in this embodiment is a plate or disk 40 which is held in place in the nozzle 12 by one or more supporting means (not shown) that can attach the plate to any inner surface of the lower chamber 44 or to the divider 41 whilst having at least partially free edges such that fluid can pass over, around and under the plate 40 to reach the second fluid exit 48.

In the embodiment of the invention shown in figure 4(c), the nozzle 12 is similar to the nozzle 12 shown in figure 4(a), except that a baffle 50 is provided at the second fluid exit 48, The baffle 50 may comprise one or more plates arranged near or next to the second fluid exit 48, or it may comprise a ring arranged around the entirety of the second fluid exit 48, or may be in any other suitable form. -16-

The embodiment of the invention shown in figure 4(d) is a rotatable nozzle 12 which is formed separately from tube 10 and is received on the end of tube 10 by sliding the outer jaws 13 of the nozzle 12 around the tube 10. The nozzle 12 and the opening defined by the jaws 13 is sized such that the nozzle 12 closely fits around the outside of tube 10, thereby grippingly retaining the nozzle 12 in place but allowing the nozzle 12 to be rotated about the tube 10 as desired and allowing second fluid exit 48 to be positioned upwardly, downwardly or in any other direction about the outer periphery of the tube 10. Engagement of the jaws 13 with the tube is fluid tight such that fluid for dispensing from the nozzle 12 does not leak out from between jaws 13 and the tube 10 outer edges.

As mentioned above, it is often important to prevent light penetrating the dispenser 2 and therefore one or more of the above components can be formed of a suitable opaque material that prevents light having one or more specific wavelengths affecting the fluid 5 in the dispenser 2. Additionally, in preferred embodiments, the dispenser 2 further comprises shielding means that can cover all or parts of the exterior of the dispenser 2 to aid in preventing penetration of light. These shielding means are particularly advantageous when it is desired to adapt a dispenser 2, that will block out certain wavelengths of light but not others, such that it also blocks out those other wavelengths. As shown in the embodiment of figure 2, the shielding means can comprise a cap 54 for covering at least the nozzle 12 at the distal end of the tube 10, and which can be formed of any suitable material and preferably is opaque to the selected wavelengths of light. Preferably the cap 52 comprises resilient plastic, rubber or other resilient polymer material and is sufficiently flexible that it can be pushed over the nozzle 12 when it is desired to store the dispenser 2.

Additionally or alternatively, the shielding means comprises a sheath or sleeve 54 that at least partially, and preferably substantially entirely, encloses tube 10.

Preferably the sleeve 54 comprises a suitable flexible material that can be pushed over the tube 10 as desired (particularly if the tube 10 is removable from the dispenser 2 and/or the nozzle 12 is removable from the tube 10). Figure 2 also shows the dispenser 2 with the nozzle 12 in the upwardly dispensing position, which can be achieved by rotating the nozzle 12 relative to the tube 10 or by rotating the tube 10 relative to the nozzle 8 or actuator 14 or in any other suitable manner. -17-

A preferred method of operation of a dispenser 2, such as the dispenser 2 shown in any of figures 1 to 4, will now be described by way of example only. As shown in figures 1 and 2, embodiments of a dispenser 2 in accordance with the present invention have a reservoir 4 and a pump mechanism 6. In the embodiments shown, a dip tube 16 is dipped into a fluid 5 that is contained in the reservoir 4 and is to be dispensed from the nozzle 12. The dip tube 16 is retained in an appropriate position relative to the reservoir 4 by being fixed to a collar 18 of the pump mechanism 6, the collar 1 8 being secured by a screw thread (not shown) received in a mating screw thread (not shown) about a neck portion 20 of the reservoir 4.

Having a collar 18 secured to the reservoir 4 in this manner allows the dispenser 2 to be opened and cleaned or refilled if desired.

The pump mechanism 6 further comprises an actuator 14 having gripping means 32 for gripping an upper end of a depressing means 28. This provides an actuator 14 that can be pulled off the dispenser 2 if desired, for example for cleaning, storage or replacement. When gripping the depressing means 28, the actuator 14 is held firmly in place relative to the depressing means 28 such that actuating the actuator 14 causes the depressing means 28 to be pushed downwardly.

The reservoir 4 is sized and shaped such that it can be grasped in the hand of a practitioner using the dispenser 2. For example, in a preferred embodiment, the reservoir 4 is sized to hold typically about 5 ml of dental fluid. The pumping mechanism 6 is sized and shaped such that a finger or thumb of the hand grasping the reservoir 4 is free to push downwards upon the actuating portion 14 of the pump mechanism 6 in order to actuate the pump mechanism 6 to draw fluid 5 into the dip tube 16. Pressing down on the actuator 14 causes the depressing means 28 to also move generally downwardly as shown in figure 3. Depressing means 28 abuts at its lower end a spring 30 which is compressed by the downward force. As is well known in the art, a pressure differential is caused by pressing down on the actuator 14 and releasing the actuator 14 causing spring 30 to expand. The pressure differential results in fluid in the tube 10 being forced toward the nozzle 12 and also fluid 5 to be drawn up from reservoir 4 into the dip tube 16 and toward the nozzle or opening 8 that is fluidly connected to the tube 10, as shown by arrows in figure 3.

Thus each actuation of the pump mechanism 6 causes fluid to be drawn into tube 10 -18-and also to be dispensed from nozzle 12 under pressure. A predetermined amount of fluid is dispensed upon each depression or actuation of actuator 14, and the amount dispensed is determined in part by the dimensions of the lower part 26 of the actuator 14 and an upper part 29 of the collar 18 which determine the maximum distance the actuator 14 can be depressed toward the reservoir 4. These components come into contact as the actuator 14 is depressed thereby determining a maximum stroke length and thus a maximum amount of fluid dispensed from the nozzle 12.

As shown in figures 4(a), (b) and (c), the pattern and angle of dispersion of fluid from the nozzle 12, and in particular from second fluid exit or nozzle exit 48, depends upon the arrangement of the nozzle 12 as well as on the pressure of the fluid in the tube 10. The nozzle 12 can be configured to give a well defined and precise spray size and area by arranging the internal components of the nozzle 12 accordingly and taking into account the viscosity of the fluid to be dispensed. It is within the capabilities of the skilled person to design such nozzles, but by way of example only, two nozzle embodiments are shown in these figures. In figures 4(a) and (b), as fluid passes through larger opening 46 between first chamber 42 and second chamber 44 its velocity is increased slightly due to the pressure caused by confining the fluid passing through the opening 46. The fluid 5 then encounters obstruction plate 40 and its velocity is further increased as the fluid flows to second fluid exit 48 where it is compressed further and exits with considerable velocity and over a wide range of angles. This provides a fine, diffuse and controlled spray of fluid 5 leaving nozzle 12.

In the embodiment of figure 4(c) the fluid 5 exiting second fluid exit 48 is further confined or hindered by baffle 50, which aids in directing the fluid 5 from nozzle 12, providing a precisely controlled and diffuse spray over a smaller area than the embodiment shown in figure 4(a) and (b). Further embodiments and configurations of nozzles 12 for use with the present invention are within the scope of the skilled persons ability to carry out the invention and will not be described here.

Therefore the above embodiments provide a spray pump capable of dispensing a metered or predetermined level of dental fluid over a controlled area that is diffusely distributed and provides a regular and even coverage of a surface to be treated. This leads to efficient wetting of tooth surfaces such as enamel or dentine and reduces or eliminates the need to spread the applied fluid by other means such as air distribution. Furthermore, the above embodiments reduce wastage as the dental fluid can be stored in the dispenser until it is required, unlike the prior art methods which require an excessive amount of fluid to be dispensed and any unused fluid to be thrown away. Furthermore the present device and method provides a more rapid application of dental fluid, thereby reducing exposure times to potentially harmful volatile and toxic chemicals and shielding the practitioner from contact with the chemicals until the fluid is dispensed from a preferably remote nozzle. Furthermore the dispenser provides an improved level of coverage of the treated surface providing improved restorations or levels of adhesive for applying indirect restorations to a tooth or the like. The dispenser is suitable for dispensing a wide range of dental fluids including, but not limited to, polymerizable sealants and adhesives including adhesive resins such as methyl methacrylate or other bonding 1 5 agents, composite resins, fissure sealants, disclosing agents, etchants, primers, treating monomers etc. Whilst the above described embodiments of the invention are shown for illustration purposes, it will be appreciated by those skilled in the art, that all of the aspects and embodiments of the invention described herein can and preferably do include any one or more or all of the preferred and optional features of the invention described herein, as appropriate. For example, whilst the embodiments disclose a first and second nozzle it is entirely within the scope of the present invention for the first nozzle to be eliminated, i.e. for the tube to be connected fluidly to the reservoir without a first nozzle interposed between the reservoir and the tube, and thus the second nozzle disclosed in the embodiments and disposed at a distal end of the tube is the only nozzle of the dispenser. Indeed references to first and second nozzle are not intended to be limiting and are used to describe the relationship between the nozzles where more than one nozzle is present. Furthermore, it should be understood that the term nozzle is intended to be given a broad definition and whilst covering means having an opening that is narrower than the surrounding region, thereby regulating or guiding fluid flow to some degree and/or compressing fluid passing therethrough, it is also intended in some embodiments to cover means -20 -having an opening that is substantially the same size as the surrounding region and therefore having little or no affect on the flow of fluid therethrough.

Claims

Claims 1. A dispenser for dispensing dental fluid, the dispenser

comprising: a reservoir; a pump mechanism; and a first nozzle fluidly connected with the reservoir by the pump mechanism, wherein, in use, a predetermined amount of dental fluid is dispensable from the nozzle by actuation of the pump mechanism.

2. A dispenser as claimed in claim 1, further comprising a tube fluidly connected with the first nozzle such that, in use, the predetermined amount of dental fluid is dispensed from the tube.

3. A dispenser as claimed in claim 2, further comprising a second nozzle, fluidly connected to the tube at the end thereof distal from the first nozzle such that, in use, the predetermined amount of dental fluid is dispensed from the second nozzle.

4. A dispenser as claimed in claim 3, wherein the second nozzle is rotatable relative to the tube.

5. A dispenser as claimed in any one of claims 2 to 4, further comprising a sleeve for at least partially surrounding the tube.

6. A dispenser as claimed in any one of claims 3 to 5, further comprising a cap for covering at least one of the first and second nozzles.

7. A dispenser as claimed in any of claims 3 to 6, wherein at least one of the first and second nozzles is removable from the pump mechanism or from the tube.

-22 - 8. A dispenser as claimed in any of claims 2 to 7, wherein at least a part of the tube is flexible.

9. A dispenser as claimed in any preceding claim, wherein at least one of the reservoir and the pump mechanism is opaque.

10. A dispenser as claimed in any of claims 3 to 9, wherein at least one of the first and second nozzles comprises: a first chamber for receiving fluid from the reservoir, said first chamber having a first fluid exit; a second chamber, fluidly connected to the first chamber by the first fluid exit and further having a second fluid exit; and obstructing means for partially obstructing flow of dental fluid in the second chamber between the first fluid exit and the second fluid exit, such that, in use, dental fluid is diffusely dispersed from the second fluid exit.

11. A dispenser as claimed in claim 10, wherein the obstructing means comprises a planar member aligned between the first fluid exit and the second fluid exit and aligned substantially perpendicularly to the direction of fluid flow, such that, in use, dental fluid in the second chamber passes over around the planar member to be dispensed from the second fluid exit.

12. A dispenser as claimed in 10 or 11, wherein the first fluid exit comprises a first opening in the first chamber, and the second fluid exit comprises a second opening in the second chamber, and wherein the first opening is larger than the second opening.

13. A dispenser as claimed in claim 10, 11 or 12, wherein the second chamber further comprises at least one baffle at the second fluid exit for further impeding the flow of fluid.

-23 - 14. A dispenser as claimed in any preceding claim, wherein the pump mechanism is a mechanical pump and further comprises: a dip tube; means for securing the pump to the reservoir; and resilient means for biasing the pump into a first position, wherein the reservoir comprises an opening for receiving the dip tube, and wherein, when the dip tube is received in the reservoir and the pump is secured to the reservoir, actuation of the pump compresses the resilient means thereby moving the pump into a second position and dispensing a predetermined amount of dental fluid.

15. A dispenser as claimed in any preceding claim, wherein the pump mechanism and the reservoir are secured together in a substantially airtight manner.

16. A dispenser as claimed in claim 15, wherein sealing means are provided between the pump mechanism and the reservoir.

17. A dispenser as claimed in any preceding claim, further comprising at least a second reservoir and a second pump mechanism, wherein, in use, a predetermined amount of a further dental fluid is dispensable from the second pump mechanism independently of dental fluid dispensable from the first pump mechanism.

18. A dispenser as claimed in claim 17, wherein the first reservoir and the second reservoir are integrally formed and comprise separate compartments of a single container, each compartment having an opening for receiving a dip tube of the corresponding pump mechanism.

19. A method of dispensing a predetermined amount of a dental fluid, the method comprising the steps of: providing a reservoir containing a first dental fluid; -24 -providing pumping means for pumping the first dental fluid from the reservoir to a nozzle; and actuating the pumping means to dispense a predetermined amount of dental fluid from the nozzle.

20. A method of dispensing a predetermined amount of a dental fluid as claimed in claim 19, wherein the pumping means comprises a mechanical pump and said step of actuating the pumping means comprises depressing the pumping means towards the reservoir a predetermined distance and releasing the pumping means after the predetermined amount of dental fluid has been dispensed.

21. A dispenser substantially as hereinbefore described with reference to any of the accompanying drawings.

22. A method of dispensing a predetermined amount of a dental fluid substantially as hereinbefore described with reference to any of the accompanying drawings.