Design process for skeletal implants to optimize cellular response

A method of designing a skeletal implant for implantation in a patient's bone at a predetermined site comprising the steps of:

• a. characterizing the patient's bone at the predetermined site with respect to the parameters of width, height, and elastic modulus;
• b. determining a general mechanical macro-design for the implant based on the width and height of the bone, and the desired biomechanical response for the implant;
• c. identifying the physiologic forces exerted by the implant on the bone at the predetermined site during functional loading of the implant;
• d. relating the identified forces exerted by the implant to the strain experienced by the bone to create strain equations for normal strain and shear strain;
• and
• e. applying the normal strain and shear strain equations using the characterization parameters of the bone as input to modify the general mechanical macro-design and thereby create a micro-design for the implant such that the normal and shear strain acting on the implanted bone minimizes resorption of the bone and enhances growth of new bone tissue adjacent the implant.

A method of designing a screw-type root-form dental implant, having a threaded attachment surface, comprising the steps of:

• a. characterizing the patient's bone at the predetermined site with respect to the parameters of width, height, and elastic modulus;
• b. generating a macro-design for the implant based on the measured width and height of the bone to be implanted and a desired biomechanical response for the implant;
• and
• c. determining a micro-design for the implant based on the measured elastic modulus of the bone whereby the size and shape of a thread on the threaded attachment surface produces a strain in the bone during functional loading of the implant that is within a predetermined range which promotes bone growth and minimizes bone resorption.

A device adapted for implanting into the existing bone of a patient and for attaching a dental prosthesis thereto, the device comprising:

• a. a crest portion having a bottom surface and an opposite top surface, the top surface being adapted for attaching the dental prosthesis thereto;
• b. a base portion having a crestal end, an apical end, and a core section with an outer surface, the crestal end being attached to the bottom surface of the crest portion;
• and
• c. means on the base portion for securing the device within the existing bone which minimizes resorption of the existing bone and promotes growth of new bone tissue adjacent the device,
• wherein the device exerts a force on the existing bone adjacent the device during functional loading which creates a level of strain in the existing bone that is less than the level of strain which causes resorption of bone and wherein the force exerted on the existing bone by the device creates a level of strain in the existing bone in the range of between about 100 microstrain and 3000 microstrain.

A device adapted for implanting into the existing bone of a patient and for attaching a dental prosthesis thereto, the device comprising:

• a crest portion having a bottom surface and an opposite top surface, the top surface being adapted for attaching the dental prosthesis thereto;
• b. a base portion having a crestal end, an apical end, and a core section with an outer surface, the crestal end being attached to the bottom surface of the crest portion;
• and
• c. means on the base portion for securing the device within the existing bone which minimizes resorption of the existing bone and promotes growth of new bone tissue adjacent the device,
• wherein the device exerts a force on the existing bone during functional loading which creates a level of strain in the existing bone of at least the minimum level of strain required to promote growth of new bone tissue adjacent the device and wherein the force exerted on the existing bone by the device creates a level of strain in the bone in the range of between about 100 microstrain and 3000 microstrain.

A device adapted for implanting into the existing bone of a patient and for attaching a dental prosthesis thereto, the device comprising:

• a crest portion having a bottom surface and an opposite top surface, the top surface being adapted for attaching the dental prosthesis thereto;
• b. a base portion having a crestal end, an apical end, and a core section with an outer surface, the crestal end being attached to the bottom surface of the crest portion;
• and
• c. means on the base portion for securing the device within the existing bone which minimizes resorption of the existing bone and promotes growth of new bone tissue adjacent the device,
• wherein the securing means comprises a continuous thread, beginning at a first end adjacent the apical end of the base portion and terminating in a second end adjacent the crestal end of the base portion, the thread forming a helix around the core section and extending radially outward from the outer surface of the core section terminating in a thread face having an outermost end, the thread having a bone contacting surface area defined between the outer surface of the core section and the outermost end, whereby the bone contacting surface area of the thread increases as the thread nears the crestal end, thereby increasing the surface area over which force is distributed from the implant to the surrounding bone.