GB2299858A

GB2299858A - Sterilisation indicator

Info

Publication number: GB2299858A
Application number: GB9507338A
Authority: GB
Inventors: Timothy James Cameron Fraser
Original assignee: FRASER LABEL Co Ltd
Current assignee: FRASER LABEL Co Ltd
Priority date: 1995-04-08
Filing date: 1995-04-08
Publication date: 1996-10-16
Anticipated expiration: 2015-04-08
Also published as: GB2299858B; GB9507338D0

Abstract

A sterilisation indicator, which may be in the form of a dental appointment card (10), comprises a heat resistant substrate including a heat sensitive marking (18) which undergoes a visible colour change on the substrate being exposed to a predetermined minimum temperature and time associated with proper heat sterilisation of medical or dental instruments. The card (10) is placed together with instruments to be sterilised, such that the card (10) is heated together with instruments. The card is in two separable parts.

Description

INDICATOR This invention relates to an indicator for use in conjunction with items to be heat-sterilised, and which provides a visual indication to show whether the indicator has been exposed to a predetermined temperature.

The increase in awareness of the possibility of the spread of communicable diseases through unsterilised dental and medical instruments has created concerns in the minds of many patients. It is among the objects of the present invention to provide an indicator which may be used to reassure patients that the instruments to be used in their treatment have been properly sterilised.

According to the present invention there is provided a sterilisation indicator comprising a heat-resistant substrate including a heat sensitive marking the appearance of which undergoes a visible change on the substrate being exposed to a predetermined minimum temperature associated with proper heat sterilisation of medical or dental instruments.

In use, the indicator is placed together with items to be sterilised, such that the indicator is heated together with the instruments. Visual examination of the indicator will immediately show whether the associated instruments have been properly sterilised. In one application, the indicator may be in the form of a dental appointment card which is handed to the dental receptionist on a patient arriving at the surgery. This card is placed with the instruments to be used during the patient's treatment, which are then sterilised. Prior to commencing treatment the dentist will return the card to the patient, which will provide a visual confirmation that the card and the instruments it was placed with have been sterilised.

Preferably, the heat sensitive marking is also time sensitive, in that it will only undergo the visual change when exposed to the predetermined minimum temperature for a predetermined minimum period. Accordingly, the marking may only undergo the visual change after having been exposed to a temperature of at least 112"C for at least one minute and thirty five seconds, which temperature and time are considered sufficient to sterilise typical stainless steel dental tools. Most preferably, the visual change is irrevocable.

Preferably also, the heat sensitive marking is in the form of a heat sensitive ink, which changes colour on exposure to a predetermined temperature.

Preferably also, the indicator includes two separable parts. Thus, one part may be retained by the patient, to be matched-up with the other part including the heat sensitive marking prior to commencement of treatment.

This and other aspects of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a plan view of a dental appointment card in accordance with a preferred embodiment of the present invention; and Figure 2 is a view from below of the card of Figure 1.

The drawings illustrate a dental appointment card, in accordance with a preferred embodiment of the present invention. The card 10 is formed of a sheet of imprintable polyester printed with various information relating to a particular dental surgery, and spaces in which information relating to a particular dental appointment may be inserted. Two signature boxes 12 are also provided on the card.

The card 10 is perforated at 16, such that it may be separated into two parts 10a, 10b. The lower part 10b includes an ink dot 18. The dot 18 is initially black, but is formulated to change colour to brown when exposed to the temperatures used to sterilise dental instruments in an autoclave for a minimum time period, typically 112"C for one minute thirty five seconds.

When attending the dental surgery, the patient brings the card 10 to the reception desk, the card then being signed in both boxes 12 and the parts 10a, 10b separated.

The patient retains the top part 10a while the lower part 10b is placed in a tray with the instruments which will be used to treat the patient. The tray of instruments and the card portion 10b are then autoclaved, ready for use.

Prior to treatment commencing, the dentist will allow the patient to see the tray of instruments and will return the card portion 10b to the patient, who may match the two portions 10a, 10b, ensuring that the signatures and card numbers 20 match, and also checking that the ink dot 18 has turned brown. Thus the patient is provided with a clear indication that the instruments have been sterilised correctly, and is reassured accordingly.

It will be clear to those of skill in the art that the above-described embodiment is merely exemplary of the present invention, and that various modifications and improvements may be made thereto without departing from the scope of the invention, for example: the ink may be formulated to match the autoclave and temperatures and times of surgeries in different localities; the layout and design of the appointment cards may of course change, depending on the requirements of any particular market or practitioner.

Claims

1. A sterilisation indicator comprising a heat resistant substrate including a heat sensitive marking the appearance of which undergoes a visible change on the substrate being exposed to a predetermined minimum temperature associated with proper heat sterilisation of medical or dental instruments.

2. The sterilisation indicator of claim 1 wherein the heat sensitive marking is also time sensitive and will only undergo said visual change when exposed to a predetermined minimum temperature for a predetermined minimum time period.

3 The sterilisation indicator of claim 2 wherein the heat sensitive marking will only undergo said visual change after having been exposed to a temperature of at least 1120C for at least 1 minute and 35 seconds.

4. The sterilisation indicator of any of the preceding claims wherein said visual change is irrevocable.

5. The sterilisation indicator of any of the preceding claims wherein said heat sensitive marking is in the form of a heat sensitive ink, which changes colour on exposure to a predetermined temperature.

6. The sterilisation indicator of any of the preceding claims wherein the indicator includes two separable parts, one part for retention by a patient, and the other part including said heat sensitive marking for placement with items to be sterilised.

7. A method of monitoring the heat sterilisation of medical or dental instruments comprising the steps: providing an indicator comprising a heat resistant substrate including a heat sensitive marking the appearance of which undergoes a visible change on the substrate being exposed to a predetermined minimum temperature associated with proper heat sterilisation of medical or dental instruments; placing the indicator together with instruments to be sterilised; heating the instruments; and examining the indicator to determine if said predetermined minimum temperature was achieved during heating of the instruments.

8. A sterilisation indicator substantially as described herein and as illustrated in the accompanying drawings.

9. A method of monitoring the heat sterilisation of medical or dental instruments substantially as described herein.