CA2748750A1

CA2748750A1 - Cap tack bone graft device

Info

Publication number: CA2748750A1
Application number: CA 2748750
Authority: CA
Inventors: John David FRENCH
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-08-11
Filing date: 2011-08-11
Publication date: 2013-02-11
Also published as: WO2013020216A1

Description

CAP TACK BONE GRAFT DEVICE
BACKGROUND

Referring to Fig. 1, an implant is illustrated in an ideal position which means that the implant is inline with the tooth root. The problem is that after extraction most dental ridge resorb and lose about 3mm or 30% of the ridge width.

Referring to Fig. 2, in a dental resorb ridge a bone graft is often needed to achieve ideal position. Compromise leads to poor loading control with long teeth on short implants and poor esthetics with long looking front teeth.

There are two main bone grafting options a particulate graft and a block of bone taken from chin or corner of the jaw. The particulate graft is done simultaneously with implant placement (I full surgery). This can be done with a "self bone" from other site in mouth i.e. corner of jaw or commercial. sources (bovine HA crystals, human donor products, etc.). The block of bone can be taken from chin or corner of jaw and it is placed before implants so requires 2 full surgeries; block placement and then implant placement.

The concept of space preservation is the key to bone graft success. A bone graft resorbs unless there is a barrier membrane to prevent soft tissue in growth. Fibrous tissue matures about 4 x faster than bone and bone needs to be separated from soft tissue and space provided for bone formation. Space is needed for bone to grow. Some membranes such as collagen are soft so do not hold space very well.

Space is needed for bone to grow. Dissolving membranes such as collagen are soft so they do not hold space very well, but are forgiving surgically if exposed.
Durable membranes of GoretexTM hold space but if exposed become growth surface for bacteria.
Fig. 3 illustrates a simultaneous bone graft. In the simultaneous bone graft procedure a bone graft can be done simultaneously with the implant. Autogenous bone from another site in mouth and commercial HA ceramic bone could be used. A barrier is needed to keep bone from mixing with soft connetive tissue of the flap. This barrier can be soft collagen or durable GortexTM. Both of which have disadvantages: soft membranes do not works to build out bone space as well; and GoretexTM is very technique sensitive.

The most common membranes are resorbable collagen or resorbable polygalactic acid.
These have forgiving property that post surgical exposures rapidly resorb and so do not track bacteria into the wound. These membranes resorb at about 4 weeks, so removal is not required making second re-open surgery easier.

However, these types of membranes do have disadvantages, they do not hold space, so bone grafting with these is limited to 1-2mm volumes. Also, they are not capable of any vertical bone gain.

GoretexTM ,( eptfe) once considered the gold standard for membrane in bone grafting is non resorbing. However, exposure leads to bacteria tracking along membrane into wound. GoretexTM is made with thin ribbing of titanium and provides space maintenance so it can rebuild large defects and even gain lost vertical bone. However, GoretexT"4 can be a dual edge sword. It is very technique sensitive with any exposure leading to bacteria wicking along membrane. The flaps must be "stretched" over wound since the bone volume is now wider than pretreatment. These flaps must be well adapted with inverted margins or epithelium will grow down along the contact margins and block full wound closure. This is typically beyond the skill of general dentists. GoretexTM is stopping eptfe dental membranes as of Aug 2411 in part because of the expansion of general dentist doing implants and the lack of skill in Goretex1"'T use.

Fig. 4 illustrates the use of collagen where gain is only within contours of the jaw and the use of GoretexTM with the gain extending beyond contour of the jaw.

to Fig. 5 illustrates an implant in an ideal position and a bone graft.
Fig. 6 illustrates an implant with the bone and GoretexTM in place.
Fig. 7 illustrates the implant 3 months later.

Fig. 8 illustrates the bone building potential of GoretexTM

However, the use of GoretexTM is technique sensitive. The membrane must be tacked on both sides. This is tricky and not readily in skill set of general dentist.
Additionally, the membrane must then also be removed and getting the pin out means doing a second large surgery.

GoretexTM holds space but is hard to use so general dentists, the larger market place, are not doing this procedure. Collagen is easy to use but does not work to build out bone.

A small titanium sheet held over implant, ti mesh has been used but is hard to fix over implant. Most mesh and or barriers fix to bone and wrap over implant. Some ideas have been suggested to fix titanium mesh to the top of the implant but they require custom casting and complex, costly machining to get it to tit in each internal part of different implant system because the internal section of each implant is proprietary.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Referring to Figs. 9- 11, in one aspect, an implant 10, a cover screw 20, a cap tack 30 and a membrane 40 can be provided.

The implant 10 is inserted into the jaw of the patient. The implant 10 can include a aperture 12 that will eventually be used to hold a artificial tooth in place when the implant 10 is fully healed and osseointegrated with the patient's jaw bone.
However, until this occurs, the cover screw 20 is inserted in the aperture 12 of the implant 10 can covers the aperture 12 and the top of implant 10 until it heals. A driver hole 22 is used to insert the cover screw 20 into the implant 10 by allowing the surgeon to insert a tool in the driver hole 22 and turn the cover screw 20, securing it in place in the implant 1Ø

The cap tack 30 is connected to the membrane 40. The membrane 40 can be a titanium mesh and in one aspect the titanium mesh can be treated with a bioactive surface to allow tissue to grow over it. The cap tack 30 is attachable to the cover screw 40 by providing an attachment to the driver hole 22 on the cover screw 20. The cap tack 30 will use a friction lock tack 32 to engage the driver hole 22 of the cover screw 20.
Rather than attaching to the aperture 12 of the implant 10, the driver hole 22 of the cover screw 20 is more universal, with only a few variations such as hex-shaped and square shaped driver holes. The friction tack 32 will "hammer-in" to the driver hole 20 of the cover screw 20 and hold down the membrane 40 over the implant 10.

In one aspect, the membrane 40 can be thin and bendable allowing it to be cut and shaped to tit the defect. In one aspect, the membrane 40 can be cut and shaped to the desired shape to provide the necessary space before being connected to the implant 10 by the attaching the cap tack 30 to the cover screw 10 inserted in the implant 10.
The membrane 40 can be covered with a collagen barrier or it can be treated with a bioactive surface to allow tissue to grow over it.

The foregoing is considered as illustrative only of the principles of the invention.
Further, since numerous changes and modifications will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all such suitable changes or modifications in structure or operation which may be resorted to are intended to fall within the scope of the claimed invention.