IE20020693A1 - A dental impression tray - Google Patents

Abstract

A dental impression tray (10) comprises a plurality of sections (11), where each section (11) is capable of interengaging with any adjacent section (11) by interlocking means, allowing for adjustment of the impression tray (10) to fit a range of jaws sizes. The interlocking means consists of a co-operating slot (19) and flange (20), which can engage in a number of incremental positions, each corresponding to a particular tray size. An adjustable impression tray (10) according to the invention can provide a range of different sizea in one tray. <Figure 1>

Description

A Dental Impression Tray This invention relates to a dental impression tray for use in obtaining impressions of the mouth and, in particular, the teeth and associated structures.

OPEN TO PUBL‘C INSPECTK W Dental impression trays are commonly used in dental practices for impression taking, for example in crown, bridge, denture and orthodontic work. Impression trays can be made of either plastics or metallic materials and are available in disposable or re-usable forms. Re-usable trays can be autoclaved or sterilised in a suitable solution after use, while disposable trays, usually made of plastics, are discarded after a single use.

In obtaining dental impressions an impression material, usually an alginate substance or a silicone-based substance, is poured into the impression tray which is then inserted into the patient’s mouth and the impression material pressed against the desired area to form an impression. These impression materials harden and set quickly to form a mould.

Accurate impressions are important for effective treatment of the patient and a properly fitting tray is the foundation of an accurate impression. At present, impression trays are only available in a set range of sizes and so a dentist must keep a large number of trays in stock to accommodate different patient sizes. Also, as the sizes are fixed, the exact fit for a particular patient may not be available and the nearest size ist ci —i— will have to be used. This may result in an inaccurate impression, possibly leading to repeat visits and further patient expense. Dentist’s time and expensive materials are wasted. A number of trays may need to be fitted to a particular patient before a suitable size is found and consequently each tray must either be re-sterilised before it can be used again or else disposed of. In a smaller dental practice, where a limited range of impression trays are kept in stock, this can result in wasted time and inconvenience for both patient and dentist.

In dental procedures, where a high degree of accuracy is required from a dental impression, a custom made tray for an individual patient can be made so that the best fit can be obtained. However, custom made trays take time to construct and so can result in repeat visits and higher costs for the patient.

The impression material needs to be held firmly within the tray to help prevent the material coming away from the tray on removal from the mouth. Certain impression trays have perforations or a rimlock feature to help overcome this problem. The impression material also needs to be held firmly against the teeth to form an accurate impression. This is a particular problem in areas where teeth are missing and at the end of the arch of teeth as the impression material tends to flow away from the surrounding teeth, giving an inaccurate impression.

After the impression has been taken the resulting mould is usually sent to a laboratory where a model is poured. This model is then analysed or used to fabricate the required prosthesis. However, IE 0 2 ο 6 9 3 laboratories often misplace the impression tray or may return another dentist’s tray in error. As it is common for trays to become lost in this manner many dentists scratch their initials onto the tray or the impression material inside. However, this is not always satisfactory as trays commonly become misplaced.

It is an object of the present invention to overcome the problems with the known impression trays as set out above.

Accordingly, the invention provides a dental impression tray comprising a plurality of sections, said sections being interengageable in a manner allowing for adjustment of the tray to fit a range of jaw sizes.

In obtaining dental impressions the accuracy of the impression is partly dependent on the fit of the impression tray. A properly fitting tray also results in greater patient comfort.

It will be appreciated that an adjustable impression tray according to the present invention can provide a range of different sizes in one tray.

An adjustable dental impression tray according to the present invention can also be made for a specific range of sizes, for example in paedodontic practice, where very small sizes, not provided by the commonly available range of tray sizes, may be required.

IE 02 06 9 J An adjustable dental impression tray according to the present invention can be used in place of custom made trays for individual patients as a range of sizes can be obtained from a single tray.

Impression trays according to the present invention can be made 5 from metallic materials, such as titanium, aluminium, chromium or stainless steel or plastics materials and may be either disposable or reusable.

Preferably, the sections are interengageable so as to allow for two-dimensional adjustment of the tray.

This arrangement has the advantage of allowing adjustment of the impression tray longitudinally or across its width or both, allowing a single tray to fit a range of jaw sizes.

In one embodiment of the invention the impression tray is provided with a pair of front sections and a pair of rear sections, each section being capable of engaging with an adjacent section by interlocking means.

The number of sections may be varied according to the amount of adjustment required.

Further, preferably, the interlocking means comprises a co20 operating flange and slot. ΙΕ η 2 Ο 6 9 ϊ Suitably, each co-operating flange and slot is capable of engaging in a plurality of incremental positions to provide a range of tray sizes.

Each incremental position corresponds to a particular tray size and so can be varied according to the tray size required.

In a further embodiment of the invention the sections, when interengaged, define a floor provided with one or more openings for receiving means for preventing flow or drag of impression material.

The prevention of flow or drag of impression material is 10 essential to ensure an accurate impression. In areas where teeth are missing this can be a particular problem as the impression material will tend to flow away from the surrounding teeth.

Preferably, the means for preventing flow or drag comprise one or more transverse barriers.

The transverse barriers can be inserted at various points in the tray and so can be inserted into areas of missing teeth or gaps in between teeth, pushing the impression material close to the surrounding teeth in use. As the transverse barriers can be used in a dental impression tray according to the invention, specialist trays are not required for taking impressions where teeth are missing.

IE Ο 2 06 9 3 Preferably, the or each transverse barrier is provided with a concave outer surface permitting a secure fit with teeth or gums in use.

This arrangement further ensures that the impression material is retained in the impression tray and is held close to the teeth or particular area of interest.

In another embodiment of the invention the impression tray is provided with a handle.

In a further embodiment of the invention the handle is removable.

In yet a further embodiment, the handle is capable of receiving 10 identification means.

The handle may be provided with a slot for inserting patient or dentist details allowing for easy and secure identification and ensuring the return of the correct impression trays from the laboratory.

The same means for identification can be applied to a removable 15 handle, for example in the case of disposable plastic trays, and may aid the dentist or dental technician in identification in the surgery or laboratory.

In another embodiment of the invention the sections are shaped to accommodate the tongue for use in taking an impression of the lower jaw. ΙΕ ο 2 ο 6 g s In this embodiment the sections suitably interengage to form a semi-circular shape with a space provided in the centre to accommodate the tongue in use.

In a further embodiment the impression tray has a plurality of perforations to prevent the distortion of impression material on removal of the tray from the mouth, thereby ensuring an accurate impression.

Impression material needs to be firmly retained inside the impression tray to prevent the impression material from coming away from the floor and walls of the tray, in particular on removal from the mouth. The perforations allow the impression material to spread and expand through the holes and so be held firmly in place while the impression is being taken and on removal from the mouth.

In yet a further embodiment the impression tray has one or more rimlock means to aid the retention of impression material within the tray on removal from the mouth.

In impression trays of the type defined herein having walls with a top surface, rimlock means in the form of a ridge or lip protruding inwards from the top of the impression tray wall allows the impression material to be held in place on removal of the tray from the mouth. Rimlock means may also be provided on the inside surface of the impression tray to further improve retention of the impression material therein.

IE 0 2 06 9 3 Rimlock means are known for use in impression trays according to the prior art.

The invention will be further illustrated by the following description of embodiments thereof, given by way of example only with reference to the accompanying drawings in which: Fig. 1 is a perspective view of a dental impression tray according to the invention; Fig. 2 is an exploded view of the dental impression tray of Fig. 1 with the handle removed; Fig. 3 is a perspective view of an interlocking means employed in the dental impression tray of Fig. 1; Fig. 4 is a sectional elevation of the interlocking means of Fig.3, taken on the line IV-IV of Fig. 3; Fig. 5 is a perspective view of a tray section with a transverse 15 barrier as used in a second embodiment of the invention; and Fig. 6 is a perspective view of a dental impression tray according to a third embodiment of the invention, for use on the lower jaw.

IE 02 06 9 3 Referring to Figs. 1 and 2 of the drawings there is illustrated, generally at 10, a dental impression tray comprising a plurality of sections 11, consisting of a pair of front sections 12 and a pair of rear sections 13, each section 11 being capable of engaging with an adjacent section 11.

When the sections 11 are interengaged they define a floor 14 and walls 15 shaped to accommodate the mouth and also to provide an area for retaining impression material in use. A raised section 16, in the centre of the assembled tray 10 is shaped to fit the palate in use.

A handle 17 is provided to aid application and removal of the tray 10 from the mouth in use. The handle is further provided with a section 18 for receiving patient or dentist identity.

Referring to Figs. 2 - 4 of the drawings, the sections 11 are capable of interengaging with each other by interlocking means 19, 20. The interlocking means is provided by a slot 19 on each section 11 capable of accommodating a flange 20 on any adjacent section 11. The slot 19 is further provided with a row of grooves 22 (Fig. 4) which correspond to size increments. Each groove 22 is capable of accommodating a projection 21 on a corresponding flange 20, allowing the sections 11 to interlock. As each groove 22 can correspond to a different size increment, the projection 21 can interlock with different grooves 22 to allow adjustment of the impression tray 10 to the required size.

Referring to Fig. 5 of the drawings, a further embodiment of the invention is indicated generally at 30. A tray floor 31 is provided with one or more openings 32 capable of receiving a transverse barrier 33, for IE 0 2 06 9 3 preventing flow or drag of impression material. The transverse barrier 33 is provided with pins 34 which are receivable in the openings 32 on the tray floor 31. In use the transverse barrier 33 provides a secure fit between the floor 31 and walls 35 of the tray 30. The transverse barrier 33 is provided with a concave outer surface 36 permitting a secure fit with teeth or gums in use.

Referring to Fig. 6 of the drawings there is illustrated, generally at 40, a dental impression tray for taking impressions of the lower jaw according to another embodiment of the invention. A pair of rear sections 41 and a pair of front sections 42 when interengaged define a floor 43 and walls 44. The sections 41, 42, when interengaged, form a semi-circular shape to accommodate the lower jaw in use. A space 45 is provided in the centre of the assembled tray 40 to accommodate the tongue in use. A handle 46 is also provided for application and removal of the impression tray 40.

Claims (15)

1. Claims: 1. A dental impression tray comprising a plurality of sections, said sections being interengageable in a manner allowing for adjustment of the tray to fit a range of jaw sizes. 5

2. A dental impression tray according to Claim 1, wherein said sections are interengageable so as to allow for two-dimensional adjustment of the tray.

3. A dental impression tray according to Claim 1 or 2, which is provided with a pair of front sections and a pair of rear sections, each 10 section being capable of engaging with an adjacent section by interlocking means.

4. A dental impression tray according to Claim 3, wherein the interlocking means comprises a co-operating flange and slot.

5. A dental impression tray according to Claim 4, wherein 15 each co-operating flange and slot is capable of engaging in a plurality of incremental positions to provide a range of tray sizes.

6. A dental impression tray according to any preceding claim wherein said sections, when interengaged, define a floor provided with one or more openings for receiving means for preventing flow or drag of 20 impression material. IE Ο 2 ο 6 9 J

7. A dental impression tray according to Claim 5, wherein the means for preventing flow or drag comprises one or more transverse barriers.

8. A dental impression tray according to Claim 5 or 6, wherein 5 the or each transverse barrier is provided with a concave outer surface permitting a secure fit with teeth or gums in use.

9. A dental impression tray according to any preceding claim, which is provided with a handle.

10. A dental impression tray according to Claim 8, wherein the 10 handle is removable.

11. A dental impression tray according to Claim 8 or 9, wherein the handle is capable of receiving identification means.

12. A dental impression tray according to any preceding claim, wherein the sections are shaped to accommodate the tongue for use in 15 taking an impression of the lower jaw.

13. A dental impression tray according to any preceding claim, having a plurality of perforations to prevent the distortion of impression material on removal of the tray from the mouth, thereby ensuring an accurate impression. 20

14. A dental impression tray according to any preceding claim, having one or more rimlock means to aid the retention of impression material within the tray on removal from the mouth. IE 02 OS 93

15. A dental impression tray according to Claim 1, substantially as hereinbefore described, with particular reference to and as illustrated in Figs. 1 - 4 and Fig. 5 and Fig. 6 of the accompanying drawings.