Surgery – Instruments – Orthopedic instrumentation
Reexamination Certificate
1999-09-29
2001-01-09
Wilson, John J. (Department: 3732)
Surgery
Instruments
Orthopedic instrumentation
C433S007000, C606S071000
Reexamination Certificate
active
06171313
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the field of oral surgery in general, and more specifically to the area of ridge augmentation of the maxilla and mandible.
2. State of the Prior Art
There are many known appliances in the prior art, used in various ways for different procedures in orthodontics. Of particular interest is applicants' mandibular distraction device as disclosed in U.S. Pat. No. 5,622,493. This device can be attached to the teeth of the mandible or maxilla for purposes of distraction after performing corticotomy. However, this device is not suitable for ridge augmentation.
Another device employed in distraction is disclosed in U.S. Pat. No. 5,364,396, employing a plurality of bone-attached screw devices. U.S. Pat. No. 4,713,000 to Rosenberg, and U.S. Pat. No. 4,571,178, also to Rosenberg, both disclose molar controlling and positioning dental appliances. However, none of these devices are suitable for ridge augmentation.
SUMMARY OF THE INVENTION
Applicants have recognized that where tooth loss may have occurred in the mandible or maxilla or where periodontal breakdown (disease) has occurred, bone deterioration can begin. That is, horizontal bone loss can occur, causing a dip or concavity along the line of the maxilla or mandible. For various reasons it is desirable to regenerate this bone. Accordingly, applicants have recognized that by performing a subapical osteotomy, and then vertically distracting the segment of bone generated in the subapical osteotomy, the bone ridge of the maxilla or mandible can be augmented, and bone tissue be restored. The method involves the gradual distraction of the bone section that has been cut in a vertical direction, i.e. in the direction in which bone regeneration is desired. The gradual distraction allows new tissue to develop at the point of distraction, so that the bone section is essentially “lifted” into place with new tissue developing around and underneath it. Thus it can be seen that the process is gradual, and it should be performed at a rate on the order of about 1 millimeter per day.
In order to perform the procedure, a suitable apparatus is necessary. Thus, applicants have developed the apparatus according to the present invention, which includes a support member that is adapted to be fixed with respect to one of the mandible and the maxilla, a bone section engagement member that is adapted to engage a bone section of one of the mandible and the maxilla, and a movement mechanism that connects the bone section engagement member with the support member for movement of the bone section engagement member relative to the support member.
Preferably, the support member comprises fixing members connected thereto for fixing the support member relative to one of the mandible and the maxilla. The fixing members can be bonded to the teeth or attached by caps, bands, removable attachments as with the attachments disclosed in applicants U.S. Pat. No. 5,735,688, which is hereby incorporated by reference. Bone plates can also be used to attach the fixing members, but bonding to the teeth is preferable.
The support member preferably comprises a bar that has the fixing members thereon for fixing the bar. The bone section engagement member includes a shaft that extends at an angle relative to the bar, and preferably substantially perpendicularly, and the movement mechanism includes a rotatable actuator and an engagement mechanism that engages the rotatable actuator with a shaft.
The movement mechanism includes a pivot block that is pivotally mounted on the bar and houses the rotatable actuator and the engagement mechanism. The engagement mechanism includes helical gear portions on the rotatable actuator and on the shaft of the bone section engagement member. Fine thread portions are provided on the shaft, and an internally threaded helical collar is provided which receives the shaft therein, engaging the fine thread portions, and has the helical gear portion of the shaft on the exterior thereof.
The rotatable actuator may also comprise a rotatable nut, with the engagement mechanism comprising internal threads of the nut and external threads of the shaft. In this variation, an unthreaded bearing can be provided in the pivot block to support the shaft at a position spaced from the rotatable nut.
The rotatable actuator can also comprise a rotatable thrust device that has a thrust collar for engagement with the pivot block. The engagement mechanism in this variation includes internal threads in the rotatable thrust device and external threads on the shaft. The thrust device preferably has a head and an upper surface of the pivot block for external rotation. The head may be a nut, or can be similar to a screw or bolt head. The pivot bar preferably comprises a through hole having a thrust shoulder at an upper end thereof for receiving the thrust device, with the thrust collar engaging the thrust shoulder.
The pivot block itself preferably comprises two through holes that are angled with respect to each other, one of the through holes receiving the bar, and the other receiving the shaft. Set screws are provided for locking both the bar and the shaft in position.
The bone section engagement member preferably comprises a fork that is connected to the shaft, the fork being adapted to engage the bone section. The fork can be made of a malleable material so as to be bendable, so that it can be adjusted in position, and further preferably forms a slight acute angle with the shaft. The fork can also be made of a stiff material.
In alternate embodiments, a rotatable distracting member is mounted between two fixing members, and orthodontic wire is used to attach to the bone segment for distraction thereof The end of the wire is connected with the member, so that upon rotation of the member, distraction of the segment takes place.
With the apparatus as described above, the present invention forms an apparatus that can be used in dental base regeneration, and includes an engagement means used for engaging a bone section of one of the mandible and the maxilla for distraction of the bone section after subapical osteotomy has been performed to form the bone section at a location in which the dental base regeneration is desired. With the apparatus as described above, there is further formed a distracting means connected between the support member and the engagement means for vertically distracting the bone section to permit dental based regeneration by vertically moving the engagement means relative to the support member in a precise and uniform manner over a period of time.
REFERENCES:
patent: 5810812 (1999-02-01), Chin
patent: 5873715 (1999-02-01), Liou
Driscoll Patrick John
Razdolsky Yan
Bumgarner Melba
Wenderoth , Lind & Ponack, L.L.P.
Wilson John J.
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