Abstract
Dental prosthetic screw, tightening tool and coupling system firstly refers to a screw for retaining and fixing a dental element in a dental implant, said dental element being able to be any component that preferably aims to support a dental structure or dental prosthesis, preferably machined or laser sintered or laser sintered and re-machined or machined by CAD/CAM, and even the structure itself or dental prosthesis. Therefore, different components are used in the manufacture of prostheses on dental implants in human implantology, requiring said components to be retained and fixed to the dental implant by means of screws on the implant. Moreover, the invention relates to a screwdriver or tightening tool compatible with said dental screw and a tightening or coupling system formed by the two.
Claims
1. A dental prosthetic implant screw with a head at one end and a thread at the opposite end, said head having a longitudinal central hollow with inner walls extending along the longitudinal axis (e) of the screw, a transverse cross section perpendicular to the longitudinal axis (e) of said hollow comprising: an opening of the hollow, consisting of a shape determined by a first circumference with a first diameter and only three outer first arcs determining three lobes that increase the transverse area of the opening, the length of said three first arcs as measured along said arcs being shorter than the circumference of half-circle with the same radius as that of said three first arcs, and the three centres of each first arc located on a same third circumference, concentric to the first circumference, and said three centres being equidistant from each other.
2. The screw, according to claim 1, characterised in that: the diameter of the third circumference is equal to 0.87 times the diameter of the first circumference, and the radius of the first arcs is equal to 0.19 times the diameter of the first circumference.
3. The screw, according to claim 1, characterised in that the length between the end of the wall at the bottom of the hollow and the outer surface of the screw head is equal to 0.68 times the diameter of the first circumference.
4. The screw, according to claim 2, characterised in that the distance between the beginning of the wall in the opening, side opposite to the bottom of the hollow, and the upper surface of the screw head, furthest from the end with the thread, is 0.20 times the diameter of the first circumference.
5. The screw, according to claim 3, characterised in that the surface between the beginning of the wall and the upper surface of the screw head is inclined/chamfered, between 30° and 60°.
6. A tightening tool, for acting in the hollow of a dental prosthetic screw according to claim 1, having an action tip, intended to be inserted in the prosthetic screw housing, at one end and a handle or support at the end opposite to that of the tip, characterised in that the tip comprises: only three projections that determine three lobes, the transverse cross section of said lobes determining at least one first outer arc in each lobe, the joining of the centres of the radii of said outer arcs which are placed in a third circumference, determining an equilateral triangle, and the longitudinal cross section of said projection or lobe of the screwdriver tip also determines an outer arc.
7. The tool, according to claim 6, characterised in that: the diameter of the third circumference of the tool (E) is ideally 1/1.17 times the diameter of the first circumference of the screw, the radius of each lobe of the tool (Red) in its transverse cross section with a larger area is ideally 1/6.4 times the diameter of the first circumference (16) of the screw, and the outer radius of the screwdriver tip H, in the longitudinal cross section of each lobe, is ideally 1/0.87 times the diameter of the first circumference (16) of the screw.
8. The tool, according to claim 6, characterised in that the transverse cross section of its tip is determined by a first circumference (F) with a first diameter and by the three first arcs (Red) that are exterior to said first circumference (F) in each lobe or projection, said cross section determining a surface with an area greater than the area of a circle having a circumference equal to the first circumference (F), the length of said first arcs (Red) as measured along said arch (15) being shorter than the circumference of half-circle with the same radius as that of said first arcs.
9. The tool, according to claim 6, characterised in that said three first arcs inscribed in, and tangent to, a second virtual circumference.
10. The tool, according to claim 6, characterised in that the centres of each first arc, equidistant from each other, are located on the third circumference with a diameter concentric to the diameter of the second circumferences.
11. A coupling system, comprising the screw and the corresponding screwdriver according to claim 6.
Description
DESCRIPTION OF THE FIGURES
[0088] To complement the description made herein and for the purpose of helping to make the features of the invention more readily understandable, a set of figures is included, which by way of illustration and not limitation represents the following:
[0089] FIG. 1 shows a perspective view of a screw according to the present invention.
[0090] FIG. 2 show a side view of the screw (2B), a side view showing the hollow in the screw head (2C) and a plan view of the screw head (2A).
[0091] FIG. 3 show a plan view (3A) and a cross section (3B) of the screw head in which the different parts of the screw head are shown.
[0092] FIG. 4 show different plan views (4A, 4C, 4E) and the corresponding elevation views (4B, 4D, 4F) thereof of three exemplary screws (10, 10′, 10″).
[0093] FIG. 5 show the plan view (5B, 5D) and an elevation view (5A, 5C) of two additional exemplary screws (10″, 10′″).
[0094] FIG. 6 show a longitudinal cross section (6A) and a plan view (6B) of the screw of FIG. 1.
[0095] FIG. 7 show a longitudinal cross section (7B) and a side view (7A) of a screw with the inclined walls of the hollow.
[0096] FIG. 8 show a longitudinal cross section (8B) and a side view (8A) of a screw with the inclined walls of the hollow, with an inclination different to that of FIG. 7.
[0097] FIG. 9 shows a perspective view of a screwdriver.
[0098] FIG. 10 show two side views (10A, 10B) of the screwdriver of FIG. 9.
[0099] FIG. 11 shows a plan view of the screwdriver head.
[0100] FIG. 12 show a screwdriver tip (12B), a transverse cross section (12A) thereof and a longitudinal cross section (12C) in which the different parts of the screw head are shown.
[0101] FIG. 13 shows a perspective view of an end of a screwdriver.
[0102] FIG. 14 show a side view (14A) of the screwdriver of FIG. 13 and four cross sections (14B, 14C, 14D, 14E) of the end of the screwdriver according to four transverse cutting planes.
[0103] FIG. 15 shows a screwdriver with a 45° inclination on a screw.
[0104] FIG. 16 shows a detailed view of the coupling area of FIG. 15.
[0105] FIG. 17 shows a cross section of the coupling area of FIG. 16.
[0106] FIG. 18 shows an enlarged detailed view of the coupling of the screwdriver head in the hollow of the screw shown in FIGS. 15 to 17.
[0107] FIG. 19 shows a perspective view of the coupling of FIGS. 15 to 18.
[0108] FIG. 20 shows a perspective view of a screwdriver without inclination (0° between axes) coupled to a screw.
[0109] FIG. 21 shows a perspective view of the coupling of FIG. 20, with the screwdriver transversally cross-sectioned by its head and coupled to the screw.
[0110] FIG. 20 shows a perspective cross section of the screw and screwdriver of FIGS. 15 to 19.
[0111] FIG. 21 shows a longitudinal cross section of the coupling of FIGS. 15 to 20.
[0112] FIG. 22 shows a longitudinally cross-sectioned dental implant on which an intermediate element with a dental prosthesis is installed, said intermediate element being fastened to the dental implant by means of a screw and a screwdriver according to the present invention.
[0113] FIG. 23 show an alternative of a screwdriver tip, with a bottom view (23A) of the tip and two side views (23B, 23C).
[0114] FIG. 24 show another alternative screwdriver tip, with a bottom view (24A) of the tip and two side views (24B, 24C).
[0115] FIG. 25 show another alternative screwdriver tip, with a perspective view (25A), a bottom view (25B) of the tip and two side views (25C, 25D).
[0116] FIG. 26 show, in a perspective view (26A) and a side view (26B), another alternative screwdriver tip with a conical projection on its lower pole.
[0117] FIG. 27 show, in a perspective view (27A) and a side view (27B), another alternative screwdriver tip without a projection in the lower pole and with this plane.
PREFERRED EMBODIMENT OF THE INVENTION
[0118] Next, and referring to the previous figures, different embodiments of the objects of the present invention will be described.
[0119] FIG. 1 shows a screw 10 object of the present invention, with a longitudinal axis “e”, and comprising a thread 12 at one end and the head 11 of the screw 10 at the end opposite that of the thread. Said head 11 has a longitudinal hollow or housing 14 for receiving the tip 150 of a screwdriver 100 or tightening/loosening tool. Said housing or hollow 14 comprises an opening determined by a first circumference 16 with a first diameter and with three first outer arcs 15 or lobes that increase the transverse surface of the opening with respect to the surface of an opening of a first circumference 16 with said first diameter. Likewise, the length of the perimeter of said opening of the housing 14 is longer than the length of the perimeter of the first circumference 16. The length of said first arcs 15 is shorter than the length of a semi-circumference, or half a circumference or circle, with the same radius as that of said first arcs 15. In turn, said three first arcs 15 are inscribed and tangent to a second circumference 17 having a diameter larger than the first circumference, said first circumference 16 and second circumference 17 being concentric with their centre on the “e” axis. Also the equidistant centres of the three first arcs 15 are located on a third circumference 18 also concentric with the first circumference 16 and second circumference 17. The joining of the first arcs 15 and the first circumference 16 is preferably carried out by means of second arcs 19, the centres of which are located on a fourth circumference 21 with a diameter that is preferably larger than the diameter of the second circumference 17. Said housing 14 is inscribed in the head 11 of the screw 10, which preferably has a circular shape with a diameter larger than the diameter of the second circumference 17. The second arcs 19 are preferably tangent to the first circumference 19 at one of the two ends thereof and tangent to a first arc 15 at the opposite end, thus determining an opening with three equidistant lobes or arcs with the same radius.
[0120] The diameter of said second arcs could vary and therefore the centre of the same could even be located on a fourth circumference with a diameter smaller than the diameter of the second circumference, but larger than the diameter of the first circumference. Said second arcs could even disappear so that the first arcs could be joined to the first circumference through sharp edges.
[0121] In said FIG. 1 it is shown how the housing 14 is determined, in addition to the form of opening thereof, by the depth of said housing, comprising walls 22 preferably parallel to the longitudinal axis “e” of the screw and following the shape of the cross section of the opening of the housing, i.e. a circumference with three projecting lobes. The shape of the walls 22 is preferably the shape of the transverse cross section of the opening of the head of the tooth described above. Alternatively, as shown in FIGS. 7 and 8, the walls may include some inclination, such that they are not parallel to the axis of the screw. FIG. 7 shows a hollow or housing with inclined walls (22′) such that the hollow is increased as it deepens therein, while FIG. 8 shows inclined walls (22″) such that the hollow is reduced as it deepens therein.
[0122] FIG. 2 shows three views of the screw of FIG. 1, wherein the different diameters discussed above and defining the shape of the opening of the housing 14 can be observed in the plan view. The shape of the inner housing or hollow can also be seen as a dotted line in one of the elevation views, with the lower end thereof or bottom having a conical longitudinal cross section. Alternatively, said lower end or bottom could be semi-circular or frustoconical. It can also be seen how the walls 22 of the housing 14 are parallel to the longitudinal axis “e” of the screw 10. However, said walls could also be slightly inclined, determining an opening with a transverse cross section larger than the cross section of the bottom of the hollow where the wall 22 ends (FIG. 8) or vice versa (FIG. 7).
[0123] FIG. 3 shows the different parts and parameters that determine the geometry and shape of the screw head, namely: [0124] Re, which represents the radius of the three first outer arcs 15, [0125] Ri, which represents the radius of the second arcs 19, [0126] A, which represents the diameter of the first circumference 16, [0127] B, which represents the diameter of the third circumference 18, [0128] D, which represents the outer diameter of the screw head 11, [0129] T, which represents the length between the end of the wall 22 at the bottom of the housing 14 and the outer surface of the screw head 11, and [0130] C, which represents the distance between the beginning of the wall 22 at the opening, side opposite the bottom of the housing 14, and the upper surface of the screw head 11 furthest from the end with the thread 12.
[0131] The ratio between these parameters is, as mentioned:
[00002]
[0132] Thus, by determining the diameter of the first circumference 16 (A) of the screw, in which the projections of the hollow of the screw are inscribed, all the dimensions of the hollow of the screw can be obtained, the diameter of said first circumference 16 (A) being between 1 mm and 3 mm in the dental sector. The screwdriver values are also obtained from these values.
[0133] FIG. 4 shows three screw alternatives, A (10″), B (10) and C (10′), according to the present invention, wherein the dimensions of the different parts of the screw vary and the variation of dimensions of the heads (11″, 11, 11′) of the screw is mainly shown, where the screw A (10″) has the head (11″) with the larger outer diameter, of approximately (X); the screw B (10) has the head (11) with the intermediate outer diameter; and the screw C (10′) has the head (11′) with the smaller outer diameter. The dimensions of the transverse cross section of the opening are also different and are determined by the diameter of the second circumference (17). FIG. 5 shows two views of two other examples of screws (10′″, 10.sup.iv), respectively.
[0134] The screws of the previous figures have the same configuration (19, 19′, 19″) with respect to the hollow or housing of the head of the screws although with different dimensions, and they also have different shapes and lengths with respect to other parts of the screw which are not object of the present invention, such as the length of the threaded end or the external shape of the screw to adapt to different housings.
[0135] FIG. 6 shows a longitudinal cross section of the screw 10 of FIG. 1 and a plan view of the head 11 thereof wherein the different diameters and dimensions making up the shape of the housing 14 can be observed.
[0136] In particular, and as has been anticipated, the dimensions of the head 11 of the screw 10 and the housing 14 thereof are determined according to the following ratios between the different parts of the screw 10: [0137] the diameter of the third circumference 18 is equal to 0.87 times the diameter of the first circumference 16. [0138] the radius of the first arcs 15 is equal to 0.19 times the diameter of the first circumference 16.
[0139] Further, the outer diameter of the head 11 of the screw 10 is approximately 1.56 times the diameter of the first circumference 16.
[0140] Likewise, with regards to the housing or hollow 14 of the head 11 of the screw 10, the same determined by the beginning of the wall 22 and the end thereof at the bottom of the hollow 14 is depressed with respect to the outer surface of the head 11 of the screw 10. The length between the end of the wall 22 at the bottom of the housing 14 and the upper surface of the screw head 11 is equal to 0.68 times the diameter of the first circumference 16. Likewise, the distance between the beginning of the wall 22 on the side opposite that of the bottom of the housing 14 and the upper surface of the screw head 11 furthest from the end with the thread 12 is 0.20 times the diameter of the first circumference 16. Thus, preferably the surface between the beginning of the wall 22 and the upper surface of the screw head 11 is inclined or chamfered, between 30° and 60°.
[0141] In FIGS. 9 to 14 a first preferred embodiment of a screwdriver 100 according to the present invention is shown. Said screwdriver 100, with a longitudinal axis “t”, preferably has a lower end with an action tip 150, which is introduced in the housing 14 arranged in the head 11 of the screw 10 to cause the rotation thereof, and an upper end preferably having a fastening area 110. Arranged between both ends is the body of the screwdriver 100, which can have a handle or body 120 after the upper grip end 110 and followed, immediately before the tip 150, by a rod 130. In any case, for the purposes of the present invention, the essential part of the screwdriver 100 is the configuration of the tip 150. In order for the screwdriver 100 to act on the screw 10, the tip 150 must be able to be coupled and act on the geometry and construction of the housing 14 of the screw 10.
[0142] FIG. 9 shows a perspective view of the tip 150 of the screwdriver 100 where the main parts thereof are shown. Specifically, the apparently spherical configuration, i.e. with a spherical appearance, is shown, defined by curved walls 154 by way of first spherical spindles, separated from each other by depressions 151 also spherical and by way of second spindles and by projections 153, by way of third spherical spindles. The third spherical spindles 153 have a thickness less than the first spherical spindles 154, while the spherical depressions 151 have a thickness less than that of the third spherical spindles 153. The depressions 151 are preferably a continuation of recesses made in the lower end of the screwdriver rod to weaken the same and enable the screwdriver to be separated into two parts in the event that a certain torque is exceeded and the screw on which said torque is applied does not rotate. This prevents damage to the screw. The tip 150 of the screwdriver is stripped at the lower part with an end 152 which may have a conical, spherical or flat shape, although it is not essential for the development of the screwdriver.
[0143] FIG. 11 shows a bottom plan view of the head or tip 150 of the screwdriver 100 and the parts described above. The infinite transverse cross sections of the tip 150 have the same shape as the transverse cross section of the housing 14 of the screw, with the difference that in the case of the screwdriver said cross sections do not have the same surface as is preferable in the housing of the screw, but rather the different cross sections vary their surface according to the transverse plane determined by the cross section on the spherical tip 150. In FIG. 14 four transverse cross sections are shown according to the cutting planes of the tip 150. It is shown how the surface of the cross sections vary depending on the cutting plane. That is, each of the different transverse cross sections of the tip 150 of the screwdriver is governed by the same ratios as the housing 14 of the screw 10. The cross section of the tip 150 with a larger surface will preferably be slightly smaller than the surface of the cross section of the housing 14 of the screw 10 so that the tip 150 of the screwdriver 100 can penetrate the housing 14 of the screw.
[0144] FIG. 12 shows a side view of the screwdriver tip, as well as a longitudinal cross section and a transverse cross section thereof wherein the parts and parameters that determine the geometry and shape of the screwdriver head are shown: [0145] Red, which represents the radius of the three first outer arcs 153, [0146] Rid, which represents the radius of the second arcs 151, [0147] F, which represents the diameter of the first circumference of the screwdriver, [0148] E, which represents the diameter of the third circumference of the screwdriver, [0149] G, which represents the distance between the larger transverse cross section of the screwdriver head and the lower end of said head, and [0150] H, which represents the outer radius on a longitudinal plane of the outer arc or projection 153.
[0151] Thus, the ratio between the parts and essential parameters that determine the geometry of the head or tip of the screwdriver to act with the screw head are: [0152] A=1.14 F=1.17 E=6.4 Red=0.87 H
[0153] FIG. 13 shows a perspective detailed view of the screwdriver tip with the recesses 141, also shown in other figures, for reducing the cross section of the screwdriver above the tip and facilitate that the same is broken through that section. FIG. 14 shows successive cross sections of the screwdriver tip. The second arcs can have a radii that goes into the body of the tip.
[0154] The following figures, from 15 to 22, show couplings formed by a screw 10 and a screwdriver 100 according to the present invention, determining a coupling system.
[0155] In particular, FIG. 15 shows a screw 10 and a screwdriver 100 with an inclination of up to 45° between the longitudinal axis of the screw 10 and the longitudinal axis of the screwdriver 100. Said inclination can preferably reach up to 50°. Thus, the screwdriver can operate on the screw 10 in the entire range between 0° and 45°, and preferably up to 50°.
[0156] FIG. 16 is an enlarged detailed view of FIG. 15 in which the tip 150 of the screwdriver 100 inside the housing 14 of the screw head 11 is also shown. A cross section of this FIG. 16 is shown in FIG. 17 where it is shown how the rod 140 of the screwdriver 100 rests on the inclined edge 13 of the housing 14 of the screw 10. FIG. 18 shows a top view of the previous coupling and FIG. 19 shows a perspective view of said coupling. FIG. 20 shows a perspective view of a longitudinal cross section of the mentioned coupling while FIG. 21 shows an elevation view of said longitudinal cross section.
[0157] FIGS. 20 and 21 show a screwdriver 100 on a screw 10, the longitudinal axis “e” of the screw 10 forming 0° with the longitudinal axis “t” of the screwdriver, i.e. both axes coinciding. FIG. 21 shows a cross section of the tip 150 of the screwdriver 100 where it can be seen how said cross section of the tip 150, according to the first embodiment of the screwdriver, coincides with the cross section of the housing 14 of the screw 10.
[0158] FIG. 22 shows a longitudinally cross-sectioned dental implant 200 on which an intermediate element 400 with a dental prosthesis 300 is installed, said intermediate element 400 being fastened to the dental implant 200 by means of a screw 10 and a screwdriver 100 according to the present invention. Due to the configuration of the screw 10 and the screwdriver, in particular due to the configuration of the housing 14 of the screw and of the tip 150 of the screwdriver, it is possible to act on the screw 10 with the screwdriver 100 when the dental prosthesis has a channel 310 with an inclination greater than 0°, and preferably up to 50°, in the figure, 45° with the axis “d” of the dental implant 200. Preferably said axis “d” of the dental implant 200 coincides with the axis “e” of the screw 10, such that the screwdriver will act on the screw with the inclination required by the inclination of the channel 310 of the prosthesis 300.
[0159] In the following FIGS. 23 to 27, the tip does not show a first circumference F complementary to the first circumference A of the screw but alternative shapes that do not interfere with said first circumference A of the screw. On the contrary, the projections of the tip are inscribed in a second circumference. In these figures too, it can be seen that the diameter of the second arcs is different to the one of the previous embodiments, and can be even larger than the previous ones or smaller. Said second arcs could even disappear so that the first arcs could be joined to the area between them through sharp edges.
[0160] FIG. 23 shows a second exemplary embodiment of a screwdriver according to the present invention. Specifically, two side views and a plan view are shown, where it is shown that the area between the projections of the screwdriver tip is almost straight, that is to say, it would not adapt to the shape of the housing of the screw existing between the projections, such that only the projections of the screwdriver would come in contact with the projections of the hollow of the screw.
[0161] FIG. 24 shows a third exemplary embodiment of a screwdriver according to the present invention, wherein the area between the projections of the screwdriver tip is slightly curved and towards the inside of the tip.
[0162] FIG. 25 shows a fourth exemplary embodiment of a screwdriver according to the present invention, wherein the area between the projections of the screwdriver tip is curved and towards the inside of the tip in a more pronounced manner than in the previous figure.
[0163] FIG. 26 shows a fifth exemplary embodiment of a screwdriver according to the present invention, similar to the screwdriver of the first embodiment, but with the lower pole thereof being pointed.
[0164] FIG. 27 shows a fifth exemplary embodiment of a screwdriver according to the present invention, similar to the screwdriver of the first embodiment, but with the lower pole thereof being flat.
