Dentistry – Prosthodontics – Holding or positioning denture in mouth
Reexamination Certificate
1999-12-06
2001-11-13
Wilson, John J. (Department: 3732)
Dentistry
Prosthodontics
Holding or positioning denture in mouth
C433S141000
Reexamination Certificate
active
06315562
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to dental implants and, in particular, to a dental implant carrier with fingers for reliably and releasably holding the dental implant assembly.
2. Background of the Related Art
In the 1930's, the first attempts to provide dental implants were unpredictable partially because of the designs and materials that were used, and partially because of poor technique. During the 1960's and 1970's, the designs, materials and techniques utilized were radically altered and predictably more acceptable results began to be achieved. Since then many further improvements have been made in this field though there is still room for additional progress, advancement and refinement.
Dental implants are surgically implanted in a patient's jaw bone to provide anchors for prosthetic devices such as crowns, bridges, dentures and the like. One modem and popular dental implant kit is packaged in a unit comprising a carrier, an insertion tool, an insertion tool screw, and an implant component or “implant”. Typically, the screw traverses a central opening in the insertion tool and is threaded into a central threaded opening in the implant, thereby attaching the bottom end of the insertion tool to the top of the implant. A carrier or handle engages the screw and/or insertion tool. The carrier is used to hold the dental implant within the package and during transport to a surgical site. The dental implant package is usually sterilized and the carrier allows the dental implant to be transported with minimal risk of contamination due to contact with the operator. The carrier also permits the implant to be partially or fully inserted into a drilled hole or osteotomy in the jaw bone of a patient. The carrier can then be pulled and/or loosened and removed and, if needed, a wrench can be used to seat the implant subgingivally into the bone.
There are several potential problems associated with conventional dental implant carriers. By way of example, a carrier
100
which is widely used today, is illustrated in
FIGS. 1A and 1B
.
FIG. 1A
shows a partially sectional view of the carrier
100
engaged with a screw
102
, and also shows an insertion tool
104
.
FIG. 1B
is a sectional view of the carrier
100
.
Referring to
FIGS. 1A and 1B
, typically, the upper end of the screw
102
has a groove
108
which is circumscribed by a small O-ring
106
. The O-ring
106
creates an interference type fit with the smooth inner bore
110
of the carrier
100
, thereby releasably securing the insertion tool screw
102
to the carrier
100
. Of course, the screw will be threadably attached to an implant (not shown), so that the carrier
100
holds the entire dental implant assembly including the screw
102
, the insertion tool
104
and the implant (not shown). Optionally, a healing screw (not shown) may also be included in the dental implant kit and typically resides in the upper part of the central bore of the carrier
100
.
This gripping mechanism incorporated by the above-mentioned interference fit between the O-ring and the carrier smooth bore can pose some problems. The O-ring, particularly since it is substantially stretched or “deformed”, may degrade and/or lose its resilience with time which can affect the quality of the above-mentioned interference fit and increases the risk of the carrier losing its grip on the dental implant, thereby permitting the dental implant to slide out. This is conceivable because it is not uncommon for a dental implant kit to be transported by common carriers and be exposed to variations in temperature and to vibrations on-the-shelf or in storage for a period of several years. It is especially detrimental and inconvenient if the dental implant slips out of the carrier during a dental procedure.
Therefore, it would be desirable to provide a dental implant carrier with a releasable gripping mechanism that can effectively and reliably grip a dental implant over a substantially prolonged period of time. Subsequently, such an implant carrier may reliably be used in dental procedures without posing a risk to the well-being of a patient.
SUMMARY OF THE INVENTION
The present invention overcomes some or all of the afore-mentioned disadvantages by providing a carrier, for a dental implant kit or assembly, with a plurality of flexible fingers for reliably and releasably retaining the dental implant, thereby, advantageously adding to the safety of the dental procedure.
In one preferred embodiment of the present invention, the implant carrier includes three flexible fingers. Preferably, the fingers are disposed in a substantially central cavity of the carrier. Preferably, the top ends of the respective fingers are attached to the wall of the carrier cavity such that the fingers are slightly spaced away from the cavity wall. The body portions of the respective fingers are generally curved and extend downwards while the bottom ends of the respective fingers bulge or project generally radially into the carrier cavity.
Preferably, the dental implant kit also includes a screw which resides at least partially in the carrier cavity. The screw preferably has a groove which is engaged by the bulging or projecting bottom ends of the respective fingers. The head of the screw is preferably substantially enveloped by the body portions of the respective fingers. Preferably, the screw traverses a substantially central cavity of an insertion tool of the dental implant kit and has a lower threaded portion which threadably engages the implant. The upper portion of the insertion tool is adapted to substantially irrotationally engage the lower end of the carrier cavity by having a hex configuration. The insertion tool and the implant are substantially irrotationally engaged with one another,
During assembly of the dental implant kit, the screw is inserted into the carrier cavity and the carrier fingers initially flex generally radially outwards as they engage the head of the screw, and are then resiliently displaced generally radially inwards as the bulging bottom ends of the respective fingers engage the groove of the screw. Advantageously and preferably, in the assembled state of the dental implant kit, the carrier fingers provide a redundant latching mechanism to capture the screw, and hence the implant since the screw is threadably engaged with the implant, by mechanically locking into the screw groove and by applying a generally radial compressive force to grip the screw. Advantageously and preferably, the fingers are unflexed or only slightly flexed in the assembled state of the dental implant kit such that the resilient displacement of the fingers is none or small when the screw is gripped by the carrier fingers. Desirably, this eliminates or minimizes the “deformation” or “pre-stressing” of the fingers in the assembled state and permits a substantially long on-the-shelf and storage life for the dental implant kit. It will be apparent to those skilled in the art that the present invention may be practiced with the carrier fingers configured to apply less, more or no radial compressive force on the screw, as required or desired. During the removal of the screw from the carrier, the fingers initially flex generally radially outwards as the bulging bottom ends of the respective fingers slip out of the screw groove and engage the screw head until the screw head is released from the fingers which are then resiliently displaced generally radially inwards to an unflexed position.
The utility of the present invention will be readily apparent to those skilled in the art from the detailed description and drawings which follow. Advantageously, the resiliency and structure of the carrier fingers not only provides a reliable long-term grip on the screw, and hence the implant, but also permit the screw, and hence the implant, to be conveniently attached and detached from the carrier.
Other specific provisions and advantages of the present invention will become apparent from a reading and study of the specification,
Knobbe Martens Olson & Bear LLP
Nobel Biocare USA, Inc.
Wilson John J.
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