CN112826617A

CN112826617A - Oral implant with novel abutment retention screw system

Info

Publication number: CN112826617A
Application number: CN202011632287.1A
Authority: CN
Inventors: 汪昆
Original assignee: Second Affiliated Hospital Army Medical University
Current assignee: Second Affiliated Hospital Army Medical University
Priority date: 2020-12-31
Filing date: 2020-12-31
Publication date: 2021-05-25
Anticipated expiration: 2040-12-31
Also published as: CN112826617B

Abstract

The invention provides an oral implant containing a novel abutment retention screw system, which comprises an implant body (1), an abutment (2), an abutment retention screw and an implant crown (4), wherein the implant body (1) comprises an implant body (11), a connecting area (12) consisting of a first cone structure (121) and a first anti-rotation structure (122), and a threaded section (13) consisting of an upper threaded section (131) and a lower threaded section (132), the abutment (2) is sequentially provided with a connecting part (21) consisting of a second cone structure (211) and a second anti-rotation structure (212) from bottom to top, a gum penetrating part (22) and a retention part (23), wherein the second cone structure (211) and the second anti-rotation structure (212) are respectively matched with the first cone structure (121) and the first anti-rotation structure (122), and the abutment retention screw comprises a long screw (31) and a short screw (32). The invention effectively solves the problem that the fastening effect of the newly replaced screw is poor after the retention screw of the abutment is loosened, and is convenient for taking out the retained screw.

Description

Oral implant with novel abutment retention screw system

Technical Field

The invention relates to the technical field of medical supplies, in particular to an oral implant containing a novel abutment retention screw system.

Background

The oral implant is also called artificial tooth root, and is a device which is implanted into the jaw bone tissue of the edentulous area of a person and the upper part of which is connected with a denture prosthesis.

Structurally, the oral implant system consists of an implant, an abutment retention screw, and an implant crown. The abutment is designed to be hollow, a channel for a screw to pass through is reserved, the lower end of the abutment is positioned at the upper end of the implant, then the abutment is fastened into the implant through the abutment retention screw, namely the implant also contains internal threads, the abutment retention screw is completely matched with the internal threads of the implant in shape and size, and after the retention screw is screwed in, no macroscopic gap exists between the abutment retention screw and the implant; the abutment upper part is a part for receiving a crown, and the crown is often fixed to the abutment by means of bonding.

A large number of clinical follow-up studies find that under the long-term repeated action of occlusal force, a part of abutment retention screws can loosen or break, which becomes the most common mechanical complication of dental implant treatment. The loosening or the breaking of the retention screw of the abutment can directly lead to the loosening of the connection between the abutment and the implant, and the implant can not bear the occlusal force normally. The treatment for loosening or breaking the abutment retaining screw is a very difficult problem faced by the prior art: on one hand, the broken abutment retention screw can be remained in the implant, and the screw is in a close contact state because no gap exists between the screw and the thread in the implant, so that the screw is difficult to take out; on the other hand, the worn loose screw is detached, and when a new screw is replaced and screwed again, the thread in the implant is worn, so that the fastening effect of the new screw after being screwed again is poor, and the situation that the new screw cannot be loosened again is difficult to avoid. Therefore, the loosening of the retention screw of the abutment becomes an urgent problem to be solved in the field of oral implantation at present, and the problem is more harmful, complex to process and poor in processing effect.

Disclosure of Invention

In view of the problems of the prior art, the present invention provides an oral implant comprising a novel abutment retention screw system, which, on one hand, ensures the smooth extraction of the abutment retention screw after the abutment retention screw is broken; on the other hand, the problem that the fastening effect is poor when the abutment retention screw is loosened and replaced can be effectively solved, and the fastening effect after the newly replaced abutment retention screw is screwed down again can be ensured to be the same as the initial fastening effect of the replaced screw.

The purpose of the invention is realized by the following technical scheme:

the utility model provides an oral cavity implant that contains novel abutment maintenance screw system, includes implant, abutment maintenance screw and implant dental crown, its characterized in that: the implant comprises an implant body, a connecting area and a thread section, wherein the connecting area and the thread section are formed in the middle of the upper end of the implant body in a recessed mode, the connecting area is arranged at the upper end of the thread section and used for being connected with a base platform, the connecting area comprises a first cone structure and a first anti-rotation structure, the first cone structure is located at the upper end of the first anti-rotation structure, the thread section comprises an upper thread section and a lower thread section, and the diameter of the upper thread section is larger than that of the lower thread section; the abutment is from lower to upper connecting portion, wears gum part and maintenance part for in proper order, connecting portion includes that second cone structure and second are anti to revolve the structure, just second cone structure, second are anti to revolve the structure and are respectively with first cone structure, first anti structure phase-match that revolves, it is the initial extension to gum horizontal part from the implant upper end to wear gum part, it is smooth continuous concave surface form and its surface from the implant upper end to gum horizontal part diameter progressively increase to wear gum part surface, the maintenance part is big end down's round platform form, its surface sets up anti inclined plane of revolving, maintenance part lower extreme with wear gum part upper end to accept and set up the restoration shoulder (namely wear gum part upper end maximum diameter department and maintenance part lower extreme form the restoration shoulder), the inside maintenance through-hole screw that sets up of abutment is used for installing the abutment screw, the diameter of the lower end of the screw through hole is the same as that of the upper threaded section; the abutment retention screw includes elongated screw and short type screw, elongated screw includes first head, first screw portion and first screw portion, just the diameter of first screw portion slightly is less than first screw portion diameter, first screw portion with the below screw thread section diameter of implant is the same, first screw portion surface is smooth, short type screw includes second head, second screw portion and second screw portion, just the diameter of second screw portion slightly be less than with second screw portion diameter, second screw portion with the top screw thread section diameter of implant is the same, first screw portion length is greater than the length of second screw portion.

Further optimization, the implant body is of a columnar structure, the diameter of the implant body is 4.5-5.5 mm, and the length of the implant body is 10-16 mm.

Further optimization is carried out, the height of the first cone structure is 2-3 mm, and the taper angle is 6-10 degrees (namely, the height of the second cone structure is 2-3 mm, and the taper angle is 6-10 degrees).

Further optimization, the second anti-rotation structure is a hexahedral structure, and the height of the second anti-rotation structure is 1mm and the thickness of the second anti-rotation structure is 0.4-0.5 mm (namely, the first anti-rotation structure is a hexahedral structure, and the height of the first anti-rotation structure is 1mm and the thickness of the first anti-rotation structure is 0.4-0.5 mm).

Further optimizing, the height of the upper thread section is 2.5-3.5 mm, and the diameter is 1.7-2.0 mm; the height of the lower thread section is 2.5-3.5 mm, and the diameter is 1.4-1.6 mm.

Further optimization is carried out, and the height of the gum penetrating part is 1-3 mm.

Further optimization is carried out, and the width of the repair shoulder is 0.3-0.5 mm.

Further preferably, the height of the retention part is 4-6 mm, and the polymerization angle is 6-10 °.

Further optimization is carried out, and the maximum diameter position of the base station is 4.5-6.5 mm (namely the diameter of the repair shoulder position).

Preferably, the first head and the second head are both cylindrical structures, and the upper surfaces of the first head and the second head are both recessed to form an inner hexagonal groove for combining the torque wrench with the long screw or the short screw so as to further fix the knob abutment with the screw.

Further optimization is carried out, the diameters of the first head part and the second head part are both 2.5-3.0 mm, and the height is 1.5-2.0 mm.

Further optimizing, the transition part of the first head part and the first screw rod part is a smooth inverted cone inclined plane, and the taper angle is 45-60 degrees; the second head with second screw rod portion transition portion is smooth back taper inclined plane, taper angle and is 45 ~ 60.

Further optimization, the diameter of the first screw rod part is 1.3-1.5 mm and is slightly smaller than the diameter of the first screw thread part by 1.4-1.6 mm, the length of the first screw rod part is 6.5-10.5 mm, and the height of the first screw thread part is 2.5-3.5 mm.

The diameter of the second screw rod part is 1.6-1.9 mm, which is slightly smaller than the diameter of the second screw thread part by 1.7-2.0 mm, the length of the second screw rod part is 4-7 mm, and the height of the second screw thread part is 2.5-3.5 mm.

Preferably, the first thread portion has a pitch of 0.35mm (and the corresponding lower thread portion has a pitch of 0.35 mm), and the second thread portion has a pitch of 0.4mm (and the corresponding upper thread portion has a pitch of 0.4 mm).

Further optimization is carried out, the thread profiles of the first thread part and the second thread part are both equilateral triangles, the thread profile angle is 60 degrees, and the thread height is 0.866 times of the thread pitch; the number of the threads of the first thread part and the second thread part is 5-6.

The implanted dental crown is a dental crown which is manufactured in a personalized mode according to the clinical occlusion condition, the tissue surface shape of the implanted dental crown is completely the same as that of the retention part of the abutment, the implanted dental crown is bonded to the retention part through the adhesive, the margin line of the implanted dental crown is stopped at the repair shoulder of the abutment, and after the implanted dental crown is worn clinically, the margin line of the dental crown is generally located 0.5-1.0 mm below the gingival margin.

The implant, the abutment and the abutment retention screw are made of biocompatible metal, metal alloy material or ceramic material.

Preferably, the biocompatible metal, metal alloy and ceramic material is one of pure titanium, pure tantalum, titanium-aluminum-vanadium alloy, tantalum-titanium alloy, zirconium oxide and the like.

The invention has the following technical effects:

the invention effectively solves the problem of looseness of the retention screw of the abutment, and when in use, the long screw is firstly screwed with the lower thread section in the implant; when the long screw is loosened, the long screw is replaced by a short screw to be screwed with the upper thread section in the implant. The diameter of the long screw is smaller than that of the upper thread section, and the first screw section of the long screw is smooth, so that when the short screw is screwed, the inner thread and the outer thread are not abraded, and the same fastening force as that of the first long retaining screw can be realized after the short screw is screwed. Meanwhile, after the first-time used long screw is broken, a certain gap exists between the first screw rod part of the long screw and the upper screw thread section, so that the long screw taking-out tool can be conveniently put in place and the long screw part left in the screw thread section can be smoothly taken out.

The invention has simple structure and convenient use, effectively solves the problem of loosening of the retention screw of the abutment in the field of dental implantation, ensures that a newly replaced screw has good fastening force and is convenient for taking out a broken screw.

Drawings

Fig. 1 is a schematic view of an abutment screw system after installation of a long screw according to an embodiment of the present invention.

Fig. 2 is a schematic view of the abutment screw system after installation of the short screw according to the embodiment of the present invention.

Fig. 3 is a schematic structural view of an implant according to an embodiment of the present invention.

Fig. 4 is a schematic structural diagram of a base station according to an embodiment of the present invention.

Fig. 5 is a schematic structural diagram of a long screw according to an embodiment of the present invention.

Fig. 6 is a schematic structural diagram of a short screw according to an embodiment of the present invention.

FIG. 7 is a schematic representation of an implant implanted into the edentulous region tissue in accordance with an embodiment of the present invention.

Wherein, 1, an implant; 11. an implant body; 12. a connecting region; 121. a first pyramidal structure; 122. a first anti-rotation structure; 13. a threaded segment; 131. an upper threaded section; 132. a lower threaded section; 2. a base station; 21. a connecting portion; 211. a second cone structure; 212. a second anti-spin structure; 22. a transgingival part; 220. repairing the shoulder; 23. a retention portion; 24. a screw through hole; 31. a long screw; 311. a first head portion; 312. a first screw section; 313. a first threaded portion; 32. a short screw; 321. a first head portion; 322. a first screw section; 323. a first threaded portion; 4. implanting a dental crown; 5. a gum; 6. bone tissue.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1:

as shown in fig. 1 to 7, an oral implant comprising a novel abutment retention screw system comprises an implant 1, an abutment 2, an abutment retention screw and an implant crown 4, and is characterized in that:

the implant 1 comprises an implant body 11, a connection region 12 and a thread section 13, the middle part of the upper end of the implant body 11 is recessed to form the connection region 12 and the thread section 13, the connection region 12 is arranged at the upper end of the thread section 13 and is used for connecting the base table 2, the connection region 12 comprises a first cone structure 121 and a first anti-rotation structure 122, the first cone structure 121 is arranged at the upper end of the first anti-rotation structure 122, the thread section 13 comprises an upper thread section 131 and a lower thread section 132, and the diameter of the upper thread section 131 is larger than that of the lower thread section 132. The implant body 11 is of a columnar structure, the diameter of the implant body is 4.5-5.5 mm, the preferable diameter is 4.5mm, and the length of the implant body is 10-16 mm, the preferable length is 12 mm; the height of the first cone structure 121 is 2-3 mm, preferably 2mm, and the taper angle is 6-10 degrees, preferably 8 degrees; the first anti-rotation structure 122 is a hexahedral structure, and the height of the first anti-rotation structure 122 is 1 mm; the height of the upper threaded section 131 is 2.5-3.5 mm, preferably 3mm, and the diameter is 1.7-2.0 mm, preferably 1.8 mm; the height of the lower threaded section 132 is 2.5-3.5 mm, preferably 3mm, and the diameter is 1.4-1.6 mm, preferably 1.5 mm.

The abutment 2 is sequentially provided with a connecting part 21, a gum penetrating part 22 and a retention part 23 from bottom to top, the connecting part 21 comprises a second cone structure 211 and a second anti-rotation structure 212, the second cone structure 211 and the second anti-rotation structure 212 are respectively matched with the first cone structure 121 and the first anti-rotation structure 122, the gum penetrating part 22 extends from the upper end of the implant 1 to the horizontal part of the gum, the surface of the gum penetrating part 22 is in a smooth continuous concave shape, the diameter of the gum penetrating part 22 is gradually increased from the upper end of the implant 1 to the horizontal part of the gum, the retention part 23 is in a round table shape with a small upper part and a large lower part, the surface of the retention part is provided with an anti-rotation inclined surface, the lower end of the retention part 23 is connected with the upper end of the gum penetrating part 22, and a restoration shoulder 220 is arranged at the connection position (namely, the maximum diameter position of the upper end of the gum penetrating part 22 and the lower end of the retention part, the diameter of the lower end of screw through bore 24 is the same as the diameter of upper threaded section 131 (i.e., the minimum diameter of screw through bore 24 is the same as the diameter of upper threaded section 131). The height of the second cone structure 211 is 2-3 mm, preferably 2mm, and the taper angle is 6-10 degrees, preferably 8 degrees; the second anti-rotation structure 212 is a hexahedral structure, the height of the second anti-rotation structure 121 is 1mm, and the thickness of the second anti-rotation structure is 0.4-0.5 mm, preferably 0.5 mm; the height of the gum penetrating part 22 is 1-3 mm, and preferably 2 mm; the width of the repair shoulder 220 is 0.3-0.5 mm; the retention part 23 has a height of 4 to 6mm and a polymerization angle of 6 to 10 degrees, preferably 8 degrees; the maximum diameter of the base 2 is 4.5-6.5 mm.

The abutment fixture screw includes a long screw 31 and a short screw 32, the long screw 31 includes a first head 311, a first screw 312 and a first screw 313, the diameter of the first screw 312 is slightly smaller than that of the first screw 313, the first screw 313 has the same diameter as that of the lower screw 132, the surface of the first screw 312 is smooth, the short screw 32 includes a second head 321, a second screw 322 and a second screw 323, the diameter of the second screw 322 is slightly smaller than that of the second screw 323, the second screw 323 has the same diameter as that of the upper screw 131, and the length of the first screw 312 is greater than that of the second screw 322. The first head 311 and the second head 321 are both cylindrical structures, and the upper surfaces thereof are recessed to form an inner hexagonal groove for combining the torque wrench with the long screw 31 or the short screw 32 so as to turn a knob abutment retention screw; the diameters of the first head 311 and the second head 321 are both 2.5-3.0 mm, preferably 2.5mm, and the heights are 1.5-2.0 mm, preferably 2.0 mm; the transition part of the first head part 311 and the first screw part 312 is a smooth inverted cone inclined plane, and the angle of the taper is 45-60 degrees, preferably 45 degrees; the transition part of the second head part 321 and the second screw part 322 is a smooth inverted cone inclined plane, and the angle of the taper is 45-60 degrees, preferably 45 degrees. The diameter of the first screw part 312 is 1.3-1.5 mm, preferably 1.4mm, the length of the first screw part is 6.5-10.5 mm, and the length of the first screw part 313 is 2.5-3.5 mm; the diameter of the second screw part 322 is 1.6-1.9 mm, the length is 4-7 mm, and the length of the second screw part 323 is 2.5-3.5 mm. The thread pitch of the first thread part 313 is 0.35mm (the thread pitch of the corresponding lower thread part 132 is 0.35 mm), the thread pitch of the second thread part 323 is 0.4mm (the thread pitch of the corresponding upper thread part 131 is 0.4 mm), the thread profiles of the first thread part 313 and the second thread part 323 are both equilateral triangles, the thread profile angle is 60 degrees, and the thread height is 0.866 times of the thread pitch; the number of the first thread part 313 and the second thread part 323 is 5-6.

The implant crown 4 is a dental crown which is made individually according to clinical occlusion conditions, the tissue surface shape of the implant crown is completely the same as that of the retention part 23 of the abutment 2, the implant crown 4 is bonded to the retention part 23 through an adhesive, the margin line of the implant crown 4 is limited to the repair shoulder 220 of the abutment 2, and the margin line is generally 0.5-1.0 mm below the surface of the gum 5. The implant 1, the abutment 2, and the abutment retention screws 31 and 32 are made of biocompatible metal, metal alloy, ceramic material, etc., such as pure titanium, pure tantalum, titanium-aluminum-vanadium alloy, tantalum-titanium alloy, zirconium oxide, etc.

The method comprises the following specific application steps: the implant 1 is a bone horizontal implant, namely the upper edge of the implant 1 is flush with the surface of the bone tissue 6 after the implant is implanted; after the implant 1 implanted in the alveolar bone is combined with bone tissues, the abutment 2 is connected, the long screw 31 penetrates through the abutment 2 and is in place, a torque wrench is adopted to apply 30-35 Ncm torque to the long screw 31 and tighten the long screw, an implanted dental crown 4 suitable for the intra-oral occlusion condition of a patient is manufactured, the dental crown 4 is bonded to the abutment 2, and the patient starts to chew food by using the implanted prosthesis. After repeated chewing in a plurality of time periods, when the long screw 31 loosens or breaks, the implanted dental crown 4 is detached, the long screw 31 is unscrewed, or the broken long screw 31 remained in the implant 1 is taken out by adopting a screw taking-out tool and replaced by a short screw 32, the short screw 32 is screwed by adopting a torque wrench, the implanted dental crown 4 is manufactured again and bonded, and the implanted dental of the patient is recovered to be normally used.

Example 2:

it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention. For example: the form and structure of the upper part of the abutment 2 are adjusted to form a connecting ring or a composite abutment 2, a bridge or an attachment part is manufactured on the upper part of the abutment, and a plurality of implant restorations with missing teeth or missing teeth in the whole mouth are carried out, or retention screws with different lengths are designed according to the connecting ring and the composite abutment 2, when one length of screw is loosened, the screw is replaced by the retention screw with other length, so as to achieve the effect of the invention.

For example, the implant 1 is designed as a soft tissue level implant 1, that is, the upper end of the implant 1 is designed to penetrate the gum, and the upper edge is higher than the bone surface, and for example, the number of the retention screws of the abutment is increased to three or more, and the number of the threads of the screws is adjusted at the same time, so that different screws are screwed with the threads in different areas in the implant 1, and the effect of repeatedly replacing the screws after loosening is achieved.

For example, the implant 1 is designed as an extra-long cheekbone or winged implant for implant treatment in special situations. The above should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the scope of the patent.

In the description of the present invention, it is to be understood that the terms "one end", "top", "middle", "other end", "upper", "one side", "inner", "front", "center", "both ends", etc., indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

Furthermore, the terms "first", "second", "third", "fourth" are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, whereby the features defined as "first", "second", "third", "fourth" may explicitly or implicitly include at least one such feature.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. The utility model provides an oral cavity implant that contains novel abutment maintenance screw system, includes implant (1), abutment (2), abutment maintenance screw and implant dental crown (4), its characterized in that: the implant (1) comprises an implant body (11), a connection area (12) and a threaded section (13), the connection area (12) and the threaded section (13) are formed in the middle of the upper end of the implant body (11) in a recessed mode, the connection area (12) is arranged at the upper end of the threaded section (13), the connection area (12) comprises a first cone structure (121) and a first anti-rotation structure (122), the first cone structure (121) is located at the upper end of the first anti-rotation structure (122), the threaded section (13) comprises an upper threaded section (131) and a lower threaded section (132), and the diameter of the upper threaded section (131) is larger than that of the lower threaded section (132); the abutment (2) is a connecting part (21), a gum penetrating part (22) and a retention part (23) from bottom to top in sequence, the connecting part (21) comprises a second cone structure (211) and a second anti-rotation structure (212), the second cone structure (211) and the second anti-rotation structure (212) are respectively matched with the first cone structure (121) and the first anti-rotation structure (122), the gum penetrating part (22) extends to a gum horizontal part from the upper end of the implant (1), the surface of the gum penetrating part (22) is in a smooth and continuous concave shape, the diameter of the surface of the gum penetrating part is gradually increased from the upper end of the implant (1) to the gum horizontal part, the retention part (23) is in a circular table shape with a small upper part and a large lower part, an anti-rotation inclined surface is arranged on the surface of the retention part (23), the lower end of the retention part (23) is connected with the upper end of the gum penetrating part (22) and a restoration shoulder (220) is, a screw through hole (24) is formed in the base platform (2), and the diameter of the lower end of the screw through hole (24) is the same as that of the upper threaded section (131); the abutment retention screw comprises a long screw (31) and a short screw (32), the long screw (31) comprises a first head part (311), a first screw part (312) and a first screw thread part (313), and the diameter of the first screw part (312) is smaller than that of the first screw part (313), the first threaded part (313) has the same diameter as the lower threaded part (132) of the implant (1), the first screw rod part (312) has a smooth surface, the short screw (32) comprises a second head part (321), a second screw rod part (322) and a second screw thread part (323), and the diameter of the second screw part (322) is smaller than that of the second screw part (323), the second thread part (323) has the same diameter as the upper thread part (131) of the implant (1), the length of the first screw part (312) is greater than that of the second screw part (322).

2. The oral implant of claim 1, wherein the implant comprises a novel abutment screw system, and the implant comprises: first cone structure (121) height can be 2 ~ 3mm, and the taper angle can be 6 ~ 10.

3. The oral implant of claim 1, wherein the implant comprises a novel abutment screw system, and the implant comprises: the second anti-rotation structure (212) is of a hexahedral structure, and the height of the second anti-rotation structure (212) can be 1mm, and the thickness of the second anti-rotation structure can be 0.4-0.5 mm.

4. The oral implant of claim 1, wherein the implant comprises a novel abutment screw system, and the implant comprises: the maximum diameter position of the base station (2) can be 4.5-6.5 mm.

5. The oral implant of claim 1, wherein the implant comprises a novel abutment screw system, and the implant comprises: the first head part (311) and the second head part (321) can be of cylindrical structures, and the upper surfaces of the first head part and the second head part are both recessed to form an inner hexagonal groove.

6. The oral implant of claim 1, wherein the implant comprises a novel abutment screw system, and the implant comprises: the transition part of the first head part (311) and the first screw rod part (312) is a smooth inverted cone inclined plane, and the taper angle can be 45-60 degrees; the transition part of the second head part (321) and the second screw rod part (322) is a smooth inverted cone inclined plane, and the taper angle can be 45-60 degrees.

7. The oral implant of claim 1, wherein the implant comprises a novel abutment screw system, and the implant comprises: the implant (1), the abutment (2) and the abutment retention screw are made of biocompatible metal, metal alloy material or ceramic material.