Patent Application
20130209959
The present invention relates in general to the field of implant dentistry. More specifically, this invention relates to a combination of two dental implants allowing the function of immediate loading after the implants placement.
In the past decades the field of dental implants evolved considerably. Branemark of Sweden found that osseointegration, i.e. the integration between a titanium-alloy implant and the jaw bone, can bear the forces of mastication, thus allowing the fabrication of a fixed or detachable dental apparatus on the implant. Branemark's perception was that in order to achieve successful osseointegration, it's imperative to prevent any loading after placing the implant for a period of 3-6 months, in order to avoid fibrous encapsulation of the implant. This delayed loading protocol was devised to prevent micromotion of the implant during the healing period. It is the excess of micromotion during the healing phase that interferes with bone repair.
The delayed healing protocol has its drawbacks, especially in edentulous patients and in cases that involve restorations of the anterior segments of the mouth.
Several types of implants were suggested in order to prevent micromobilty, thus allowing the dental practice of immediate loading, i.e., loading the implant within a period of 0-96 hours after it's placement in the jaw.
Some designs of prior implants used a mechanism that utilizes an internal screw in order to expand plural apical legs radially and outwardly into the bone thus causing an anchoring effect. U.S. Pat. No. 2,721,387 was issued to Ashuckian (1955) for a dental implant with apical expansion design. U.S. Pat. No. 3,708,883 was issued to Flander (1973) for an implant with two expanding legs in the apical side of the implant. Similar concepts were utilized in apical expansion designs by Lazarof (1992) U.S. Pat. No. 5,087,199, and U.S. Pat. No. 5,681,187 Lazarof (1997), and Hanosh (1996) U.S. Pat. No. 5,489,210, and U.S. Patent No. 2010/0304333 A1 (Ghavidel) That show expandable dental implants. The problem with all these designs is the risk of micro-leakage of bacteria and other microorganisms from the oral cavity, through the micro gaps that exist between the female threads of the internal channel and the male threads of the expansion screw. Other drawbacks of these designs can be breakage of the expanding legs at their bases and damage to the peripheral bone during expansion.
Another kind of expanding implant is described in U.S. Pat. No. 6,227,860 issued to Hobo (2001). In this implant the expanding part is in the middle of the spindle shaped implant. Still, there might be a problem with micro-leakage even in this design, hence the need for a locking system that doesn't include those longitudinal channels along the whole length of implants, which might be a vessel for various microorganisms.
One of the problems when the need comes for multiple implants is the lack of bone height and the poor quality of bone especially in the posterior parts of the oral cavity. The absence of bone led to the development of full arch prostheses which use only four supporting implants. Paolo Malo from Nobel Biocare introduced the “All-On-Four” concept in which a full arch prosthesis is supported by four implants. The immediate stability of the supporting implants is essential in those cases of minimum bone volume.
Inserting an implant to the bone in an oblique angle can add up to fifty percent more to the length of the inserted implant, allowing more bone-to-implant contact and improved support. Hence insertion of two tilted implants increases the bone-to-implant contact by up to 100 percent. Furthermore, tilting the implants can provide the necessary gap between the coronal ends of the implants or the abutments for a stable support of a dental superstructure.
Our present invention can resolve the problem by allowing the insertion of longer implants obliquely into the jaw and securing the two implants together, thus allowing sufficient stability for immediate loading. The splinting of 2 implants can also enhance the stability to eccentric forces.
Most modern dental implants have either one piece or two piece designs without any internal channel. Our present invention uses such one or two piece dental implants, made from titanium/titanium alloy or ceramic/zirconium compounds. The lack of internal channels that vessel the expansion screws up to the apical side of the implant reduces the possibility of micro-leakage in said one piece or two piece implants. When using two piece tilted implants, an angled abutment can be used to allow proper seating of the dental prostheses. U.S. Patent No. 2011/0027756 A1 (Benatouil) describes one-piece inclined dental implant and its advantages compared to two piece implants. U.S. Patent No. 2009/0298013 A1 (Baruc) describes an inclined abutment assembly device that can be attached to a standard two piece implant.
To position the implants one may use Computer Aided Design (CAD) procedures. The three dimensional model can aid in fabrication of a surgical template and in selecting the appropriate length and width of the implants. It is possible to fabricate the dental bridge prior to placing the implants and using a template device for transferring the position of an angled abutment from a model to an implant as described in U.S. Patent No. 2009/0047628 A1 (Malo).
The following summary is a simplified description of some embodiments of the present invention. A more detailed description is discussed later. In one embodiment a combination of two inclined dental implants forms a coupled structure that enhances resistance to rotational, occlusal and lateral forces allowing immediate loading of said dental implants thereof. The said first implant has an angled threaded bore at the apical end and said second implant comprises an upper coronal threaded shaft and a thinner apical threaded part fitted for the said bore, wherein the second implant is inserted in an angle unto said angled bore located in the apical part of the first implant.
Furthermore, to facilitate the proper angled drilling for the said coupled implants, our present invention suggests a device comprised of a cylindrical implant body try-in with the desirable angle, width, length and an angled bore at the apical end of the try-in, and an attachment member which is connected to the implant try-in. The connecting member comes with a tilted sleeve for inserting a drill in a desired angle for the second implant.
The features and advantages of the present invention are herein described, by way of example only, with reference to the accompanying drawings, in which:
The present invention comprises a method of locking two implants together so as to enhance the immediate stability of both implants allowing immediate loading. Said implants are inserted in an angle to the jaw and are locked tightly together thus forming a compound structure that enhances resistance to rotational, occlusal and lateral forces. The use of two pairs of the present invention implants can be a solid foundation for an immediate loading full arch prosthesis which uses only four supporting implants. The principles and features of the present invention will become clear with reference to the drawings and the accompanying descriptions, in which:
The first step (
The present invention described above relates to certain embodiments. However, these embodiments have been presented by way of example only. Other embodiments than those described above are possible within the spirit and scope of the invention, as defined in the appended claims.
