Dental contact matrix limited

Abstract

A dental contact matrix system is described for the placement of dental fillings. The dental contact matrix system includes a matrix, a retainer for placing and retaining the 5 matrix and an elastic wedge. The retainer includes two lugs or tines that fit between two teeth on the buccal and lingual sides of the teeth. The lugs are connected by a spring member that presses the lugs against the lingual and buccal sides of the teeth. There is an adaptation to hold the elastic wedge in a stretched condition between the lugs.

The invention claimed is: 
     
       1. A retainer for placing and retaining a matrix in a dental contact matrix system, and for use in conjunction with an elastic “wedge”, said retainer comprising:
 a first lug, to fit on one side of a proximal contact between two teeth, 
 a second lug to fit on the other side of said proximal contact, 
 a spring member connecting between said first lug and said second lug, said spring member holding said lugs such that they must be separated to fit over said proximal contact, wherein the spring member applies a restorative force pressing said lugs against opposed sides of said proximal contact, and 
 means for receiving and holding an elastic wedge in a stretched condition to span between said first lug and said second lug. 
 
     
     
       2. The retainer as claimed in  claim 1  for use in conjunction with a wedge comprising a one piece member of elastic material and having:
 an elongate narrow section, and 
 an elongate tapered section with a triangular cross section, said elongate narrow section extending from the narrow end of said tapered section; 
 wherein each said lug of said retainer includes a ridge for projecting into the proximal contact, and said means for receiving and holding an elastic wedge receives and holds said wedge with said elongate narrow section spanning between said ridge of said first lug and said ridge of said second lug. 
 
     
     
       3. The retainer as claimed in  claim 2  wherein said means for receiving and holding an elastic wedge comprises:
 a first wedge engagement associated with said first lug, 
 a guide on said first lug to have said wedge exit from underneath said first lug at said ridge, 
 a second wedge engagement associated with said second lug, 
 a guide on said second lug to have said wedge exit from underneath said second lug at said ridge. 
 
     
     
       4. The retainer as claimed in  claim 3  wherein said first and second wedge engagements each comprise a cleat formed in an end of said spring member adjacent the connection between said spring member and the respective said lug. 
     
     
       5. A dental contact matrix system including a retainer for placing and retaining a matrix in a dental contact matrix system, an elastic “wedge” and a matrix, said retainer comprising:
 a first lug, to fit on one side of a proximal contact between two teeth, 
 a second lug to fit on the other side of said proximal contact, and 
 a spring member connecting between said first lug and said second lug, said spring member holding said lugs such that they must be separated to fit over said proximal contact, wherein the spring member applies a restorative force pressing said lugs against opposed sides of said proximal contact; 
 said elastic wedge being held in a stretched condition spanning between said first lug and said second lug. 
 
     
     
       6. The dental contact matrix system as claimed in  claim 5  wherein said wedge has:
 an elongate narrow section, and 
 an elongate tapered section with a triangular cross section, said elongate narrow section extending from the narrow end of said tapered section; 
 each said lug includes a ridge for projecting into the proximal contact, 
 and said means for receiving and holding an elastic wedge holds said wedge with said elongate narrow section spanning between said ridge of said first lug and said ridge of said second lug. 
 
     
     
       7. The dental contact matrix system as claimed in  claim 6  wherein said means for receiving and holding an elastic wedge comprises:
 a first wedge engagement associated with said first lug, 
 a guide on said first lug to have said wedge exit from underneath said first lug at said ridge, 
 a second wedge engagement associated with said second lug, 
 a guide on said second lug to have said wedge exit from underneath said second lug at said ridge. 
 
     
     
       8. The dental contact matrix system as claimed in  claim 7  wherein said first and second wedge engagements each comprise a cleat formed in an end of said spring member adjacent the connection between said spring member and the respective said lug, said narrow section of said wedge engaging in each said cleat. 
     
     
       9. A retainer for placing and retaining a matrix in a dental contact matrix system, and for use in conjunction with an elastic “wedge”, said retainer comprising:
 a first lug, to fit on one side of a proximal contact between two teeth, 
 a second lug to fit on the other side of said proximal contact, 
 a first matrix-support member positioned to retain a matrix against said first lug, 
 a second matrix support member positioned to retain a matrix against said second lug, and 
 a spring member connecting between said first lug and said second lug, said spring member holding said lugs such that they must be separated to fit over said proximal contact, wherein the spring member applies a restorative force pressing said lugs against opposed sides of said proximal contact. 
 
     
     
       10. The retainer as claimed in  claim 9  wherein:
 said first lug includes a pair of tooth abutting faces, said tooth abutting faces meeting at a ridge for projecting into the proximal contact between two teeth, 
 said first matrix support member is positioned to retain a matrix against one said tooth abutting face, being a support face, 
 said second lug includes a pair of tooth abutting faces opposing said tooth abutting faces of said first lug, said tooth abutting faces meeting at a ridge for projecting into proximal contact between two teeth, said ridge opposing said ridge of said first lug, and 
 said second matrix support member is positioned to retain a matrix against the said tooth abutting face of said second lug that is opposed to said support face of said first lug, being a support face of said second lug. 
 
     
     
       11. The retainer as claimed in  claim 10  wherein each said lug includes a ledge extending forward from said support face along an upper edge of said support face, to in use bear against the upper edge of a dental contact matrix held against said support face by a respective support member. 
     
     
       12. The retainer as claimed in  claim 10  wherein said spring member follows an open loop path largely in a plane substantially perpendicular to the direction of said ridges of said lugs and above said lugs, to leave the space between said lugs unobscured by said spring member when viewed from above said plane. 
     
     
       13. The retainer as claimed in  claim 12  including a releasable engagement between each said first and second lug and said spring member, each said releasable engagement allowing for connection of each of said first lug and said second lug, such that said first and second lugs may be mounted to said spring member in:
 a first condition wherein said support faces of said first lug and said second lug face away from said open loop path of said spring member, and 
 a second condition wherein said support faces of said first lug and said second lug face toward said open loop path of said spring member. 
 
     
     
       14. The retainer as claimed in  claim 13  wherein said releasable engagement comprises a plug and socket, engageable along an engagement axis, said engagement axis being parallel with said ridges of said first and second lugs, and being near perpendicular to said plane of said open loop path. 
     
     
       15. The retainer as claimed in  claim 12 , for use in conjunction with a wedge comprising a one piece member of elastic material, and having:
 an elongate narrow section, and 
 an elongate tapered section with a triangular cross section, said elongate narrow section extending from the narrow end of said tapered section, 
 wherein said retaining member includes means for receiving and holding said wedge with said elongate narrow section spanning between said ridge of said first lug and said ridge of said second lug. 
 
     
     
       16. The retainer as claimed in  claim 15  wherein said means for receiving-and holding an elastic wedge comprises:
 a first wedge engagement associated with said first lug, 
 a guide on said first lug to have said wedge exit from underneath said first lug at said ridge, 
 a second wedge engagement associated with said second lug, and 
 a guide on said second lug to have said wedge exit from underneath said second lug at said ridge. 
 
     
     
       17. The retainer as claimed in  claim 16  wherein said first and second wedge engagements each comprise a cleat formed in an end of said spring member adjacent the connection between said spring member and the respective said lug. 
     
     
       18. The retainer as claimed in  claim 12  including an arrangement for enabling an expansion tool to expand said spring member, said arrangement including a pair of engagements on said spring member, each engagement near a respective said lug. 
     
     
       19. The retainer as claimed in  claim 18  wherein each said engagement comprises an inward protrusion from said spring member. 
     
     
       20. The retainer as claimed in  claim 9  wherein said first matrix support member is connected with said first lug, and is spaced from a support face of said first lug. 
     
     
       21. The retainer as claimed in  claim 20  wherein said first matrix support member is substantially parallel with said support face, and is spaced forward of said support face, and outward of an edge of said support face away from said ridge. 
     
     
       22. The retainer as claimed in  claim 21  including a further support member connected with said first lug, parallel with said first support member, and spaced further out and behind said first support member. 
     
     
       23. The retainer as claimed in  claim 20  wherein said second matrix support member is connected with said second lug, and is spaced from said support face of said second lug. 
     
     
       24. The retainer as claimed in  claim 23  wherein said second matrix support member is substantially parallel with said support face, and is spaced forward of said support face, and outward of an edge of support face away from said ridge. 
     
     
       25. The retainer as claimed in  claim 24  including a further support member connected with said second lug, parallel with said second support member, and spaced further out and behind said second support member. 
     
     
       26. The retainer as claimed in  claim 9  wherein at least one said lug is formed from a light transmissive material. 
     
     
       27. The retainer as claimed in  claim 26  wherein said light transmissive lug is formed such that at least a good proportion of light entering said lug from above exits said lug toward said teeth. 
     
     
       28. A retainer for retaining a matrix, the retainer comprising:
 a first lug to fit on a first side of a proximal contact between two teeth, said first lug having a first and second tooth abutting face, said first and second tooth abutting faces of said first lug diverging from a first ridge between said first and second tooth abutting faces of said first lug and substantially normal to the gingival margins of said two teeth throughout the length of said first ridge, said first tooth abutting face of said first lug configured to abut the first of said two teeth and said second tooth abutting face of said first lug configured to abut the second of said two teeth,   a second lug to fit on a second side of the proximal contact, said second lug having a first and second tooth abutting face, said first and second tooth abutting faces of said second lug diverging from a second ridge between said first and second faces of said second lug and substantially normal to the gingival margins of said two teeth throughout the length of said second ridge, said first tooth abutting face of said second lug configured to abut the first of said two teeth and said second tooth abutting face of said second lug configured to abut the second of said two teeth,   a first dental wedge receiving notch in said first lug, the said first dental wedge receiving notch adjacent to and extending from said first ridge in said first lug towards the gingival margins of said two teeth and a second dental wedge receiving notch in said second lug, the second dental wedge receiving notch adjacent to and extending from said second ridge in said second lug towards said gingival margins of said two teeth, said first and second dental wedge receiving notches aligned to receive and position a dental wedge across the interproximal space between said two teeth, wherein the first dental wedge receiving notch and second dental wedge receiving notch correspond in size and dimension; and   a spring member connecting between the first and the second lug, the spring member holding said first and second lugs such that the lugs are separated to fit over the proximal contact, the spring member applying a restorative force pressing said first and second lugs against opposed sides of the proximal contact.   
     
     
       29. The retainer for retaining the matrix of claim 28 wherein said first and second ridges are rounded. 
     
     
       30. The retainer for retaining a matrix of claim 28 wherein said first and second dental wedge receiving notches consist of a generally inverted V-shape contour wherein the top of said first dental wedge receiving notch is adjacent to said first ridge and the top of said second dental wedge receiving notch is adjacent to said second ridge. 
     
     
       31. The retainer for retaining a matrix of claim 28 wherein said first ridge in said first lug consists of a curved contour and wherein said second ridge in said second lug consists of a curved contour. 
     
     
       32. The retainer for retaining a matrix of claim 28 wherein a first and second arm of the spring member has a protrusion for engaging a tool used to expand the spring. 
     
     
       33. The retainer for retaining a matrix of claim 28 wherein the spring member is generally U-shaped in plan view. 
     
     
       34. The retainer for retaining a matrix of claim 28 wherein at least one of said lugs is substantially transparent. 
     
     
       35. The retainer for retaining a matrix of claim 34 wherein both said lugs are substantially transparent. 
     
     
       36. The retainer for retaining a matrix of claim 28 wherein said first and second tooth abutting faces of said first lug each consist of curved contour as each face extends between the top and bottom of said first lug wherein said first and second tooth abutting faces of said second lug each consist of curved contour as each face extends between the top and bottom of said second lug. 
     
     
       37. The retainer for retaining a matrix of claim 36, wherein at least one of the first or second tooth abutting faces of the first lug has a curved contour across that tooth abutting face as it diverges from the first ridge. 
     
     
       38. The retainer for retaining a matrix of claim 28 wherein each of said two teeth on opposite sides of the proximal contact comprise a mesial, a distal, a lingual and a buccal surface, and said first tooth abutting face of said first lug is configured to abut the first of said two teeth at the distal and buccal surfaces of said first tooth, and said second tooth abutting face of said first lug configured to abut the second of said two teeth at mesial and buccal surfaces of said second tooth, and wherein said first tooth abutting face of said second lug configured to abut the first of said two teeth at distal and lingual surfaces of said first tooth and said second tooth abutting face of said second lug configured to abut the second of said two teeth at mesial and lingual surfaces of said second tooth. 
     
     
       39. The retainer for retaining a matrix of claim 28, wherein the tooth abutting faces, ridge, and dental wedge receiving notch of the second lug are a mirror image of the tooth abutting faces, ridge, and dental wedge receiving notch of the first lug. 
     
     
       40. The retainer for retaining a matrix of claim 28, wherein the lugs are constructed of a plastic material, the lugs being attached to metal arms of the spring member.