CN102319125B

CN102319125B - Anti-loosing and corrosion-proof dental-implant central screw

Info

Publication number: CN102319125B
Application number: CN 201110216722
Authority: CN
Inventors: 于海洋; 甘雪琦
Original assignee: Sichuan University
Current assignee: Sichuan University
Priority date: 2011-08-01
Filing date: 2011-08-01
Publication date: 2013-04-10
Anticipated expiration: 2031-08-01
Also published as: CN102319125A

Abstract

The invention discloses an anti-loosing and corrosion-proof dental-implant central screw, which is characterized in that the minor thread diameter of the screw is 1.5-2.5 mm, the height of a thread form of the screw is 1/10 of the minor thread diameter, and the surface of the screw is coated with a phosphorus-containing TiO2 membrane by using a sol-gel method; the thread form of the central screw is triangular, the flank angle of a leading flank is 30 degrees, and the flank angle of a following flank is 20 degrees; the thread crest is arc-shaped, junctions between a thread root and the leading flank as well as the following flank are also arc-shaped, and the curvature radiuses of the arc-shaped parts are all 1/50 of the minor thread diameter; the pitches between five channels of screw threads (close to a screw cap) of the central screw are 0.4-0.5 mm, the thread root inclines inwards along the screw cap, and a 10-degree included angle is formed between the thread root and a thread axis; and the pitches between the other screw threads are 0.8-1.0 mm, and the thread root is parallel to the thread axis. The central screw disclosed by the invention is uneasy to loose, difficult to corrode, reliable in performance and long in service life, therefore, the central screw can be used for improving the long-term success rate of dental implants.

Description

A kind of locking etch-proof dental-implant central screw

Technical field

The present invention relates to a kind of dental prosthetic parts of tooth implant, relate in particular to the central screw of tooth implant.

Technical background

Along with the development of bone Integration Theory is improved and the clinical practice of many decades, the tooth plantation has become one of focus of repairing technology of anodontia, compare with traditional removable denture, fixed denture repair mode, the tooth plantation has the advantages such as attractive in appearance, that comfort level is high, masticatory function is stronger.Although recent research shows 5 years success rates of tooth implant and can reach 94.8% (upper jaw), 97.5% (lower jaw), Zong success rate is 96.1%.But along with the further prolongation of active time, the success rate at a specified future date of tooth implant but has the trend of further reduction, follows up a case by regular visits to success rate in external 16 years to be reported as 82.94%, and domestic 11～15 years success rate of following up a case by regular visits to is reported as 62.5%.In numerous tooth implant failure case, the loosening failure phenomenon that waits of central screw is comparatively common, therefore, explores the locking countermeasure of dental-implant central screw, has become the key technical problem of further raising tooth implant success rate at a specified future date.

Central screw is to connect tooth implant two large parts---plant the important component of body and base station.The threaded portion of central screw passes base station and matches with the female thread of planting body, and its nut then cooperates with the inwall of base station realizes planting being connected of body and base station.Dental-implant central screw is tiny, the about 2mm of average diameter, and the in addition existence of following factor is very easily become flexible it:

There are two contact interfaces between inner other members of dental-implant central screw and implantation body: 1, the central screw of bottom-implant interface, 2, the central screw on top-base station interface.Chewing etc. under the functional status, these two connect the interface micron-sized relative displacement can occur, its motion amplitude exactly is in the motion amplitude scope of " fine motion " in the tribology, the damage that this fine motion brings can cause screw contact surface material loss, size variation and cause the loosening of screw; And under arms in the process, the suffered stress of central screw and heterogeneity, stress mainly concentrates on the thread crest place and near on several roads screw thread of the root of nut and central screw and base station junction, main stressed screw thread stress is about 200MPa, indivedual positions stress concentration is serious, be 304MPa to the maximum, these stress concentration positions are easy damaged more, thereby causes the loosening of central screw even fracture.

In addition, there is special small gap (width is generally in 0.05～0.08mm scope) between above-mentioned each interface.And central screw is on active service in very special oral cavity corrosive environment, a large amount of moisture and enzyme, the temperature of variation and the fatigue aging that pH value, tooth force action and dysfunction, bad habit etc. can cause implantation body's fixed screw holes closed material in the oral cavity, cause marginal seal not good enough, little Seepage can't be avoided, and Korrosionsmedium is easy to be penetrated in the special small gap at central screw interface; In the operation process, the central screw surface also inevitably can be subject to the pollution of liquid etc. in saliva, blood, the art.Above factor causes very easily corrosion of central screw, thereby makes its degradation, inefficacy; Simultaneously, corrosion also can be accelerated the loosening of central screw.

Summary of the invention

The objective of the invention is to design a kind of locking etch-proof dental-implant central screw, this central screw is difficult for loosening, also not perishable, dependable performance, and long service life can improve the success rate at a specified future date of tooth implant.

To achieve these goals, the technical scheme of taking of the present invention is, a kind of locking etch-proof dental-implant central screw, and the screw thread path is 1.5～2.5mm, and thread height is 1/10 of screw thread path, and its construction features is:

The surface of described central screw adopts sol-gel process to be coated with phosphorous TiO ₂Film; The form of thread of central screw is triangle, and the tooth side angle of guiding tooth side is 30 °, and the tooth side angle of following the tooth side is 20 °; Crest is arc, also is arc with guiding tooth side and the intersection of following the tooth side at the bottom of the tooth, and the radius of curvature of these arcs is 1/50 of screw thread path;

Compared with prior art, beneficial effect of the present invention is:

One, anti-corrosion treatment has been carried out on the central screw surface, namely adopted sol-gel process at the even phosphorous TiO of central screw surface preparation ₂Film, phosphorous TiO ₂Film can significantly improve its corrosion resistance as the protecting film on central screw surface, make its under arms in the process resistant function to Korrosionsmedium in the interface gaps strong, can prolong its service life.

Two, be asymmetry towards the guiding tooth side of direction of advance with the relative tooth side of following during central screw precession of the present invention, the tooth side angle (the between perpendiculars angle of guiding tooth side and screw thread axis) of guiding tooth side is 30 °, the tooth side angle (following the between perpendiculars angle of tooth side and screw thread axis) of following the tooth side is 20 °, so that the tooth side angle of screw thread guiding tooth side is greater than the tooth side angle of following the tooth side, thereby reduce the resistance of screw advancement and increase the resistance that screw thread retreats, can effectively increase the bearing capacity of screw, prevent screw loosening.

Crest is arc, also be arc with guiding tooth side and the intersection of following the tooth side at the bottom of the tooth, the arc curvature radius is 1/50 of screw thread path, so that all screw thread transition interface are arc and seamlessly transit, avoid the existence of any type of sharp corners, therefore can effectively reduce fretting damage; In addition, arc transiting surface makes central screw surface obtain larger surface area, and the contact area stress distribution is more even and be unlikely to produce stress concentration.

In a word, central screw of the present invention can finely prevent from becoming flexible, dependable performance, and long service life can improve the success rate at a specified future date of tooth implant.

Above-mentioned central screw is 0.4～0.5mm near the pitch of 5 road screw threads of nut, along the introversion of nut direction, is 10 ° angle with the axis of thread at the bottom of the tooth; The pitch of other screw thread is 0.8～1.0mm, and is parallel with the axis of thread at the bottom of the tooth.

Central screw is the main stress-bearing area in the military service process near 5 road screw threads of nut (also namely with base station junction), and it is 0.4～0.5mm that the thread pitch that this is regional reduces by half, with better dispersive stress; And along the introversion of nut direction, be 10 ° angle with the axis of thread at the bottom of the tooth of this 5 road screw thread, further increase retreats resistance, strengthens the ability of bearing load, better prevents screw loosening.

The lower surface of the nut of above-mentioned central screw is downward-sloping, is 30 ° angle with the axis of thread.

Like this, make the position, root boundary of nut and screw thread avoid forming right angle corner, reduced the stress concentration of this corner, simultaneously also increased should the position, boundary lifting surface area, can bear larger screw-down torque, make its connection more firm.

The present invention is further detailed explanation below in conjunction with the drawings and specific embodiments.

Description of drawings

Fig. 1 is the structural representation of the embodiment of the invention.

Fig. 2 is the enlarged drawing of local A among Fig. 1.

Fig. 3 is the enlarged drawing of local B among Fig. 1.

The specific embodiment

Embodiment

Fig. 1-3 illustrates, and a kind of specific embodiment of the present invention is: a kind of locking etch-proof dental-implant central screw, and screw thread path D (with the diameter of cylinder tangent at the bottom of the tooth) is 1.5～2.5mm, thread height H is 1/10 of screw thread path D, wherein:

The surface of central screw adopts sol-gel process to be coated with phosphorous TiO ₂Film; The form of thread of central screw is triangle, the tooth side angle α of guiding tooth side 3 ₁Be 30 °, follow the tooth side angle α of tooth side 4 ₂It is 20 °; Crest 1 is arc, and 2 also are arc with guiding tooth side 3 and the intersection of following tooth side 4 at the bottom of the tooth, and the radius of curvature of these arcs is 1/50 of screw thread path D;

Fig. 1 and Fig. 2 illustrate, and this routine central screw is 0.4～0.5mm near the pitch of 5 road screw threads of nut, along the introversion of nut direction, is 10 ° angle γ with the axis of thread at the bottom of the tooth; Fig. 1 and Fig. 3 illustrate, and the pitch of other screw thread of this example is 0.8～1.0mm, and be parallel with the axis of thread at the bottom of the tooth.

Fig. 1 also illustrates, and the lower surface of the nut of the central screw that this is routine is downward-sloping, is 30 ° angle theta with the axis of thread.

Claims

1. locking etch-proof dental-implant central screw, screw thread path (D) is 1.5～2.5mm, thread height (H) is 1/10 of screw thread path (D), it is characterized in that:

The surface of described central screw adopts sol-gel process to be coated with phosphorous TiO ₂Film; The form of thread of central screw is triangle, the tooth side angle (α of guiding tooth side (3) ₁) be 30 °, follow the tooth side angle (α of tooth side (4) ₂) be 20 °; Crest (1) is arc, and (2) and guiding tooth side (3) and the intersection of following tooth side (4) also are arc at the bottom of the tooth, and the radius of curvature of these arcs is 1/50 of screw thread path (D);

2. a kind of locking etch-proof dental-implant central screw according to claim 1, it is characterized in that: described central screw is 0.4～0.5mm near the pitch of 5 road screw threads of nut, along the introversion of nut direction, be 10 ° angle (γ) with the axis of thread at the bottom of the tooth; The pitch of other screw thread is 0.8～1.0mm, and is parallel with the axis of thread at the bottom of the tooth.

3. a kind of locking etch-proof dental-implant central screw according to claim 1, it is characterized in that: the lower surface of the nut of described central screw is downward-sloping from outside to inside, is 30 ° angle (θ) with the axis of thread.