Method and apparatus for determining the preload for screws for dental implant systems

• US 6,358,051 B2
• Filed: 12/07/2000
• Issued: 03/19/2002
• Est. Priority Date: 12/07/1999
• Status: Expired due to Fees

• Current Assignee: Andrei Ptchelintsev, Brien R. Lang, Gr. Maev, Roman
• Original Assignee: Andrei Ptchelintsev, Brien R. Lang, Gr. Maev, Roman
• Inventors: Lang, Brien R., Gr. Maev, Roman, Ptchelintsev, Andrei
• Primary Examiner(s): Lucchesi, Nicholas D.
• Application Number:
  US09/731,590
• Publication Number:
  US 20010034009A1
• Time in Patent Office: 467 Days
• Field of Search: 433/173, 433/174, 433/175, 433/176, 433/72, 433/27, 737/61
• US Class Current: 433/173
• CPC Class Codes: A61C 1/186 with torque adjusting or limiting means
• CPC Class Codes: A61C 19/04 Measuring instruments specially adapted for dentistry A61C5/44 takes precedence; testing vitality of teeth A61B5/0534; radiation diagnosis specially adapted for dentistry A61B6/51
• CPC Class Codes: A61C 8/005 Connecting devices for joining an upper structure with an implant member, e.g. spacers
• CPC Class Codes: A61C 8/0054 having a cylindrical implant connecting part
• CPC Class Codes: A61C 8/006 with polygonal positional means, e.g. hexagonal or octagonal
• CPC Class Codes: A61C 8/0069 tapered or conical connection
• CPC Class Codes: A61C 8/0089 Implanting tools or instruments

Abstract

A method and apparatus are provided for determining the preload in a dental implant system. The preload is determined by transmitting a sonic impulse, which is preferably an ultrasonic impulse, at a predetermined frequency to the head of the implant screw through a transducer, which may be incorporated into the head of the screw, the head of a wand which generates the sonic impulse, or the transducer and pulse-generating instrumentation may be incorporated into a torque generating instrument used to tighten the screw. The preload is determined by measuring the delay between the first and second reflections through the preloaded screw to determine a preload value and comparing that value with a pre-established baseline value for the screw, and comparing the difference with a predetermined table of values to determine the preload on the screw.

Claims

1. A method of determining the pre-load on a screw that secures a component to other components in a dental implant system comprising:

a. Transmitting a sonic impulse at a predetermined frequency to the head of the screw through a transducer when the screw is in an unstressed condition;

b. Measuring a first delay between first and second reflections through the unstressed screw, and establishing a baseline value for the unstressed screw;

c. Applying a preload of a predetermined value to the screw to secure implant components together;

d. Transmitting a sonic impulse at a predetermined frequency to the head of the preloaded screw through a transducer;

e. Measuring a second delay between the first and second reflections through the preloaded screw to establish a preload value; and

f. Determining the difference between the first delay and the second delay to establish a difference between the baseline value and the preload value, and comparing the difference with a predetermined table of values to determine the preload on the screw.

2. The method of claim 1 wherein the sonic impulse is an ultrasonic impulse.

3. The method of claim 1 wherein the screw secures an abutment to an implant.

4. The method of claim 1 wherein the screw secures a dental prosthesis to an abutment.

5. The method of claim 1 wherein the screw secures a dental prosthesis directly to an implant.

7. The apparatus of claim 1 wherein the sonic impulse is an ultrasonic impulse.

8. The apparatus of claim 1 wherein the screw secures an abutment to an implant.

9. The apparatus of claim 1 wherein the screw secures a dental prosthesis to an abutment.

10. The apparatus of claim 1 wherein the screw secures a dental prosthesis directly to an implant.

11. The apparatus of claim 1 wherein the means for transmitting a sonic impulse is an apparatus that produces an ultrasonic impulse.

12. The apparatus of claim 1 wherein the means for transmitting the sonic impulse through the screw and detecting first and second reflections of the pulses is a transducer.

13. The apparatus of claim 12 wherein the transducer is affixed to the head of the screw.

14. The apparatus of claim 12 wherein the transducer is affixed to a wand, and the wand is in electronic communication with an electronic control and measurement circuit.

6. Apparatus for determining the preload on a screw in a dental implant system that includes at least one screw for securing components of the dental implant system together, wherein the dental implant system includes at least a fixture having one end adapted for osseointegration into a jawbone, the other end adapted to receive an abutment, and the abutment adapted to receive and support a dental prosthesis, the apparatus further comprising

a. Means for applying a preload to the screw to secure at least some components of the implant system together;

b. Means for transmitting a sonic impulse at a predetermined frequency to the head of the screw;

c. Means for transmitting the sonic impulse through the screw and detecting first and second reflections of the pulses;

d. Means for measuring the delay between the first and second reflections through the preloaded screw to determine a preload value; and

e. Means for determining the difference in the delay between a pre-established baseline value for the screw and the preload value, and comparing the difference with a predetermined table of values to determine the preload on the screw.