GB2439926A

GB2439926A - Dental gauge

Info

Publication number: GB2439926A
Application number: GB0613486A
Authority: GB
Inventors: Timothy Patrick O'brien
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-07-06
Filing date: 2006-07-06
Publication date: 2008-01-16
Also published as: GB0613486D0

Abstract

A dental gauge 1 comprising a ball 2 having a known diameter mounted on a first end of a flexible shaft 3. The shaft may be releasably attached to a handle 4. The device is of particular use for in preparing teeth to receive crowns.

Description

imProved Dental Gaugç This invention relates to an improved dental

gauge and in particular to an improved dental gauge for use in preparing teeth to receive crowns.

In dentistry, when carrying out restorative procedures it is generally necessary to remove material from a tooth to a predetermined depth or to provide a predetermined clearance for the restorative material which is to be added to the tooth later in the restorative procedure.

Where the restorative procedure is a filling, tooth material must usually be removed to form a cavity of predetermined depth relative to the surface of the tooth.

Where the restorative procedure is the fitting of a crown, tooth material must be removed to provide a predetermined spacing relative to the interior surface of the crown.

In order to allow this spacing to be measured the usual technique is to form a rigid silicon matrix having the same shape and size as the crown. This matrix is then sectioned and placed over the tooth to which the crown is to be attached during preparation of the tooth so that the dentist can judge when sufficient tooth material has been removed to provide the required clearance.

The most common method for judging the required clearance is to estimate the size of the gap by eye or to insert a rigid instrument of known dimensions. However, it is difficult and awkward to introduce a rigid instrument into the space between the exposed tooth surface and the inner surface of the matrix, particularly because this must be carried out within the patients mouth so that the range of available angles from which the instrument may be introduced or observed and the available clearances for movement and manipulation are relatively small.

This is a particular problem when the surface of the tooth is curved. In this case is necessary to section the matrix into a number of slices In order to allow the clearance to be checked along the full length of the prepared surface. It will be understood that this is a very slow and tedious operation which, in reality is often impractical because of time or cost constraints on the dentist.

As a result, there is a problem that an incorrect amount of tooth material is often removed during restorative work so that the available space for the restorative material is too small or unnecessarily large. Where the space available for the restorative material is too small this can compromise the strength and/or appearance of the restored material so that the restored tooth suffers breakage or is cosmetically unacceptable. Where the available space is too large because too much of the tooth material is removed, the remaining tooth is weakened, which may lead to the failure of the tooth, and the health of the tooth nerve may be compromised.

In practice it has been found that the more common problem is removal of insufficient tooth material so that there is insufficient space for the restorative material. It is believed that this is because of the natural tendency of dentists to "play safe" when judging whether sufficient material has been removed.

This invention was made in an attempt to overcome these problems, at least in part.

In a first aspect, this invention provides a dental gauge comprising a ball having a known diameter mounted on a first end of a flexible shaft.

A preferred embodiment of the invention will now be described by way of example only with reference to the accompanying diagrammatic figures, in which: Figure 1 shows an example of dental gauge according to the invention; and Figure 2 shows an enlarged view of a part of the dental gauge of figure 1.

The dental gauge 1 according to a preferred embodiment of the invention comprises a spherical ball 2 having a known diameter mounted at the first end of a flexible shaft 3, the flexible shaft being narrower than the diameter of the spherical ball 2. The other end of the flexible shaft 3 is attached to a handle 4 shaped to enable the gauge to be easily grasped and manipulated by a user.

In the preferred embodiment, the shaft 3 is solid and formed of a flexible metal, such as a nickel-titanium alloy and the ball 2 is a solid metal sphere formed on or around the end of the shaft 3. It is expected that it will be particularly convenient to manufacture the ball 2 and shaft 3 integrally formed from the same flexible metal.

The handle 4 can be formed from any suitable material. For cheapness and ease of manufacture the handle can be formed from a rigid plastics material. The shaft 3 can be permanently secured to the handle 4 by injection moulding or otherwise forming the plastics material of the handle 4 around the base of the shaft 3.

The dental gauge I is used during a dental restorative procedure to check whether a desired amount of tooth material has been removed by grasping the handle 4 and manipulating the gauge 1 so that the ball 2 is placed within the cavity formed by removal of the tooth material.

The ball 2 of the gauge I is selected to have a diameter the same as the required cavity depth.

As a result, it is veiy easy to check whether the correct thickness of tooth material has been removed from the cavity by visually comparing the ball 2 with the cavity depth or side height.

Further, the baIl 2 can easily be moved around within the cavity to check that all parts have the desired depth regardless of the shape or extent of the cavity or any curvature of the tooth surface in which the cavity is formed.

The diameter of the ball 2 is fixed so that plurality of gauges having different ball sizes may be used to allow different depths of cavity to be measured.

The gauge 1 according to the invention is particularly useful for measuring clearances for crowns.

Firstly, a conventional silicon matrix with the same interior shape as the crown is placed over the tooth. A gauge I is then selected having a ball 2 with a diameter conesponding to the width of the desired space to be formed between the tooth surface and the interior surface of the crown. The size of the space can then easily be measured by inserting, or attempting to insert the baIl 2 into the space and manipulating the gauge 1 to move the ball 2 around within the space. I.

In addition to allowing the width of the space to be more accurately measured than before, the dental gauge according to the present invention also provides the further advantage that by checking whether the ball 2 will move througJ all parts of the space it is possible to confirm that the space has the correct width throughout, even in areas which cannot be observed, or cannot be clearly seen.

The use of an elastically flexible material to form the shaft 3 provides the advantage of allowing easy insertion and movement of the baIl 2 within cavities, and particularly in annular spaces between crowns and teeth.

In the embodiment described above, the handle 4 is permanently fixed to the shaft 3 to form the gauge I so that in order to use a different sized ball 2 to measure cavities of different sizes a different gauge 1 must be used.

In an alternative embodjrneni, the shaft 3 is detachably connected to the handle 4 by the end of the shaft 3 having an externally screw threaded portion cooperating with a internally threaded aperture or recess in the handle 4. Other known forms of detatchable connection could also be used.

This alternative embodiment allows the size of the ball 2 to be changed by attaching a different shaft 3 and ball 2 to the handle 4. This alternative embodiment may also be preferred for reasons of economy if it is intended to dispose of the ball 2 and shaft 3 after use for hygiene reasons.

It is not essential that the ball 2 and shaft 3 be solid. However, in view of their small size this is expected to be the most practical arrangement.

The use of nickel-titanium flexible alloy for the shaft is not essential, other materials having suitable characteristics could be used.

As explained above, it is expected that when the gauge I according to the present invention is used a range of shafts 3 or complete gauges I having different diameter balls 2 will be available. In order to avoid the possibility of confusion it is preferred that the gauge I should be boldly and clearly marked with an indication of the ball size. Where the shaft 3 is detachable from the handle 4 this marking may advantageously be colour coding because a numerical size indication on the shaft 3 or ball 2 may be too small to be readily legible.

As explained above, the gauge according to the invention can advantageously be used to measure clearances in removing tooth material. However, the gauge can also be used for other dental measurement purposes such as measuring gaps between the sides of adjacent teeth or measuring gaps between the biting surfaces of opposed teeth.

The examples of the invention described herein are not exhaustive. The skilled person will be able to envisage alternative arrangementa falling within the scope of the invention as defined in the attached claims.

Claims

Claims I. A dental gauge comprising a ball having a known diameter

mounted on a first end of a flexible shaft.

2. The dental gauge according to claim 1, and further comprising a handle attached to a second end of the flexible shaft.

3. The dental gauge according to claim 2, in which the flexible shaft is releasably attached to the handle.

4. The dental gauge according to any preceding claim, in which the shaft is formed of a nickel-titanium alloy.

5. The dental gauge according to any preceding claim, in which the ball and shaft are integrally formed.

6. A dental gauge substantially as shown in or as described with reference to the accompanying figures.