Dentistry – Prosthodontics – Holding or positioning denture in mouth
Reexamination Certificate
1999-12-16
2001-10-09
Wilson, John J. (Department: 3732)
Dentistry
Prosthodontics
Holding or positioning denture in mouth
C433S181000
Reexamination Certificate
active
06299447
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to dental attachment or anchoring structures for attaching dental appliances such as full dentures or overdenture partial dentures, and the like to a remaining non-vital root, an adjacent tooth, or to an endosseus implant.
In U.S. Pat. No. 5,417,570 of Zuest et al., a dental anchor assembly is described in which a female part for attachment to a tooth root or implant has a socket, and a male part has a first end for snap engagement in the socket and a second end in swivel engagement in a cap for securing in a recess in a dental appliance. This provides for some relative movement at both ends of the male part, reducing the risk of excessive wear and loosening of the attachment.
It has been found that, in use, it is sometimes difficult for the wearer to properly locate the female socket, so that the mating, retentive end or head of the male part may hit the edge of the female part when the wearer inserts the denture. Repeated impacts of this type may damage the retentive head of the male, reducing or losing the retention force required for proper operation of the attachment.
Other prior art attachments utilize a male head which is in releasable snap engagement with a female socket, but do not provide a double hinging action since the male part is secured in the denture cap with no freedom of movement. Also, these arrangements do not always avoid the risk of damage to the retentive head of the male due to improper alignment with the female when re-inserting the denture or appliance. U.S. Pat. No. 5,195,890 of Sulc describes an attachment in which the cap and male are formed in one part, the cap having an integral, internal projection forming the male retentive head. U.S. Pat. No. 5,556,280 of Pelak describes an attachment system in which a male member is of cup-shaped structure, with an internal projection for snap-fit retention in the female socket. The male member is embedded in a receptacle or directly in the appliance.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a new and improved dental attachment assembly.
According to one aspect of the present invention, a dental attachment assembly is provided, which comprises a female socket member for attachment to a tooth root, implant, or adjacent tooth, the socket member having an upper end, a socket projecting inwardly from the upper end, and an outer locating surface portion projecting downwardly from the upper end, the outer locating surface portion being positioned to project above the tissue level when the socket member is secured in a tooth root or implant, a male retention member having an upper end for engagement in a recess in a dental appliance, a retention head projecting from the upper end for releasable snap engagement in the female socket, and a locator skirt projecting from the upper end of the male retention member surrounding the retention head, the skirt having an inner surface for releasable snap engagement over the outer locating surface portion of the female socket member for aligning the retention head with the socket as the male retention member is secured to the female socket member.
The lower end of the skirt preferably projects below the retention head so that it will contact the locating surface portion of the female socket member prior to the retention head, reducing or avoiding the risk of damaging the head, and helping to properly align the retention head prior to its entry into the socket.
In one embodiment, the locating surface has an outwardly bulging upper portion, while the inner surface of the skirt has a corresponding concave ring portion for snap engagement over the upper portion. This provides outside as well as inside snap retention of the dental appliance on the female member. This will reduce wear and increase the lifetime of the attachment. Alternatively, in this case, the inner snap engagement may not be needed, and the retention head and corresponding socket may be eliminated.
In a preferred embodiment of the invention, the outer locating surface portion of the female socket member has formations such as a pair of diametrically opposed notches for engagement with an insertion tool for engaging the female member with a tooth root or implant. A weep hole preferably connects the socket to the outside of the female member for allowing saliva to escape and reducing hydraulic pressure resulting from the male engagement in the female socket.
The female socket member may form an angled abutment for anchoring to implants extending at various implants. The angled abutment has a lower, connecting portion for securing the socket member to an implant or tooth root, the lower portion having a first axis, and an upper portion in which the socket is located, the socket having a second central axis at an angle to the first axis. Abutment members at various angles are provided. Alternatively, a two part angled abutment assembly may be provided, with an angled abutment member having a through bore and a separate fixation screw extending through the bore to secure the abutment member to an implant.
According to another aspect of the invention, an attachment assembly is provided for securing a dental appliance in a gap adjacent to an abutment tooth. The assembly comprises a female socket member having an upper end, a socket projecting downwardly from the upper end, an attachment extending to one side of the socket for securing the socket member to a tooth, the socket member having an outer locating surface portion projecting downwardly from the upper end, a male retention member having an upper end for engagement in a recess in a dental appliance, a retention head projecting from the upper end for releasable snap engagement in the female socket, and a skirt projecting from the upper end of the male retention member surrounding the retention head, the skirt having an inner surface for releasable snap engagement over the outer locating surface portion of the female socket member for aligning the retention head with the socket as the male retention member is secured to the female socket member. The skirt and locating surface are designed for releasable snap engagement with one another for better retention.
According to another aspect of the invention, a dental attachment assembly is provided which comprises a first member for attachment to a tooth root, implant, or adjacent tooth and a second member for engagement in a recess in a dental appliance. The first member has an upper end and an outer locating surface portion positioned to project above the tissue level when the first member is secured to a tooth root, implant, or adjacent tooth. The second member is generally cup-shaped and has an upper end and a skirt depending downwardly from the upper end for engagement over the outer locating surface portion of the first member, the skirt having an inner surface, the inner surface of the skirt and outer locating surface portion of the first member having mateable, snap-engaging formations so that the skirt can be releasably snap engaged over the first member.
In a preferred embodiment of the invention, the first member has an outward bulge extending around its periphery adjacent its upper end, and the inner surface of the skirt has a corresponding annular, inward concavity for snap engagement over the bulge. This provides an outside snap retention of the male or second member over the first or female member. Additionally, the skirt will readily locate the female member and will self-center for snap engagement.
In addition to the outside snap retention, the first or female member may also be provided with an upwardly facing socket, and the second or male member may have a retention head projecting downwardly from the upper end for snap engagement in the socket as the skirt snaps over the outside. This combined inside and outside snap gives much better retention than just inner snap retention, and reduces wear problems. The outside snap will still provide retention even when the inner snap engaging surfaces wear out. This coul
Mullaly Scott
Zuest Paul T.
Brown Martin Haller & McClain LLP
Wilson John J.
Zest Anchors, Inc.
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