GB2243783A

GB2243783A - Dental pin

Info

Publication number: GB2243783A
Application number: GB9010554A
Authority: GB
Inventors: Peter Brett Robinson; Brian James Millar
Original assignee: National Research Development Corp UK
Current assignee: National Research Development Corp UK
Priority date: 1990-05-10
Filing date: 1990-05-10
Publication date: 1991-11-13
Also published as: GB9010554D0

Abstract

A dental pin capable of affixing an indirect restoration preferably comprises an end receiving the restoration which is tapered, provided for example by a downwardly divergent tapered stud 8 onto which a temporary restoration may be affixed, whilst a permanent restoration is prepared. The temporary restoration may then be removed and the permanent indirect restoration affixed. The end receiving the restoration may be treated to aid dental cement adhesion as by sandblasting or coating, and may be provided with a removable protective sleeve 5. A neck 4 may be provided to assist in bending. <IMAGE>

Description

DENTAL PIN This invention relates to a dental pin capable of affixing an indirect restoration.

Current methods of restoration involve the dental operator to remove,as required because of disease,the coronal parts of the tooth and directly apply a composite restoration. This restoration remains in place due to bonding between the composite restoration and enamel of the tooth. Often in large restorations additional support in the form of a pin would be desirable. Conventional pins are rigid, with a lower region comprising an external thread and a top region having circumferential ribs which extend for the entire length of the upper region, until reaching its rounded head. Some dental pins have a shouldered stop between the external thread and the circumferential ribs. The only bending permitted by such a pin is a curved bend within the upper region to aid anchorage.The overall rigidity of the pin means that if they are inserted at angles to each other, as is often the case, and desirable for direct restorations, the ribbed anchoring post is at an angle to the tooth, and hence removal of any impression or temporary restoration is impossible.

What would be advantageous, is a dental pin designed so as to permit an impression to be made and removed to the laboratory for preparation of a permanent indirect restoration whilst a temporary restoration is applied. Such a pin could also enable more of the original tooth to be preserved by transferring stress to the pin rather than the weakened coronal tooth structure.

Accordingly, the present invention is a dental pin capable of affixing an indirect restoration. Preferably the end receiving the restoration is tapered. The taper is preferably divergent towards the end inserted into the tooth. The taper is preferably from 150 to 250. Preferably, the dental pin comprises a neck between its ends which is preferably of narrower diameter than the end receiving the restoration, for example from 10 to 15% narrower in diameter. The neck is preferably a metal neck.

It is preferable that a removable (preferably plastic) sleeve encloses the end receiving the restoration and the said neck. The sleeve is preferably at least 50 pm to at most 200 pm in thickness, especially from at least 100 pm to at most 150 vm thick. The protective sleeve when removed provides a route by which excess cement may escape. A further preferred feature of the end receiving the restoration is that its tapered surface is treated to aid adhesion to dental cement.This may be achieved by sandblasting alone or by sandblasting and then coating with a bonding agent using methods known to those skilled in the art, for example by treating with a Silicoater (Registered Trade Mark) or SR-Isosit SPECTRA Link, in which case the protective sleeve will additionally protect the coated surface. Preferably the end receiving the restoration is from 2 mm in height for use on anterior teeth to 3 mm in height for use on molars and premolars.

The invention will now be described by way of example with reference to the accompanying drawing. This is a schematic diagram of a dental pin according to the invention. An externally threaded rigid cylinder 1 of height 2.5 mm, has a point at one end for insertion into a pre-drilled pin channel, and a shouldered stop 2 at its other end. A metal neck 4 extends from the stop 2 to a tapered stud 8, the stud being downwardly divergent from its apex to the metal neck 4, the angle of taper being from 15 to 250. The metal neck 4 is of narrower diameter than the tapered stud by 10 to 15%. The tapered stud 8 may be treated to aid adhesion, by means of sandblasting alone or sandblasting and coating with a bonding agent as described hereinbefore.The total height of the end receiving the restoration from the shouldered stop 2 to the apex of the tapered stud 8 is 2 mm for pins to be used on anterior teeth or up to 3 mm for pins to be used on molars or premolars. A protective plastic sleeve 5 covers the stop 2, metal neck 4 and tapered stud 8. A shear zone 6 is present between the apex of the stud 8 and a latch grip bur shank 7. The pin is made of metal or alloy.

In use, the pins are inserted into pre-drilled pin channels by fitting the shank 7 of the dental pin into a standard drill. The pins as a whole are screwed into the pin channels; the stop 2 will prevent the pins from being screwed in too far. It is irrelevant whether the pins are screwed in parallel to one another as the taper of the stud will permit removal of an impression or temporary restoration. If, regardless of the taper, the pins are still notsufficiently parallel to permit this, the studs may be adjusted to a more mutually parallel position by means of bending about the metal neck. The neck absorbs all the bending deformation enabling the tapered stud to be bent upright whilst remaining straight.

When all the necessary pins have been inserted and their studs are all sufficiently parallel, an impression of the tooth may be made.

This impression by virtue of the tapered stud may be removed to the laboratory for preparation of a permanent restoration. Meanwhile, a temporary restoration can be placed and will be mechanically held in place, retention being assisted by the protective sleeve. Upon subsequent removal of the temporary restoration, the plastic sleeve will be removed, exposing the coated surface of the tapered stud.

As the permanent restoration is prepared with holes for the studs in it, the permanent restoration will fit onto the studs and be affixed by means of dental cement.

Due to the removal of the said plastic sleeve, an escape channel exists for the cement, resulting in the permanent restoration being anchored by being cemented to the dental pin and the tooth. The use of the dental pin is not limited to indirect restorations (gold, porcelain, composite) but is also suitable for direct restorations.

Claims

1. A dental pin capable of affixing an indirect restoration.

2. A dental pin according to Claim 1, in which the end receiving the restoration is tapered.

3. A dental pin according to Claim 2, in which the taper diverges towards the end inserted into the tooth.

4. A dental pin according to Claim 2 or 3, in which the taper is at least 150.

5. A dental pin according to Claim 2, 3 or 4, in which the taper is at most 25".

6. A dental pin according to any of Claims 2 to 5, comprising between its ends a neck about which the pin may be bent.

7. A dental pin according to Claim 6, in which the neck is at least 10% narrower in diameter than the end receiving the restoration.

8. A dental pin according to Claim 6 or 7, in which the neck is at most 15% narrower in diameter than the end receiving the restoration.

9. A dental pin according to any of Claims 6, 7 or 8, the said neck being of metal.

10. A dental pin according to any of Claims 2 to 9, comprising a removable sleeve enclosing the end receiving the restoration and the neck if present.

11. A dental pin according to Claim 10, the said sleeve being a plastic, protective sleeve.

12. A dental pin according to Claim 10 or 11, in which the sleeve is at least 50 pm thick.

13. A dental pin according to any of Claims 10, 11 or 12, in which the sleeve is at most 200 pm thick.

14. A dental pin according to any of Claims 10 to 13, in which the sleeve is at least 100 pm thick.

15. A dental pin according to any of Claims 10 to 14, in which the sleeve is at most 150 pm thick.

16. A dental pin according to any of Claims 2 to 15, in which the end receiving the restoration is sandblasted.

17. A dental pin according to any of Claims 2 to 16, in which the end receiving the restoration is coated to aid adhesion.

18. A dental pin according to Claim 16 or 17, in which the end receiving the restoration is coated in siloxane.

19. A dental pin according to any of Claims 2 to 18, in which the end receiving the restoration is at least 2 mm in height.

20. A dental pin according to any of Claims 2 to 19, in which the end receiving the restoration is at most 3 mm in height.