Tooth extraction tool

Abstract

To provide a tooth extraction tool which can be applied for various kinds and forms of tooth roots, allow tooth extraction in a short time for reducing a load applied to a patient.SOLUTION: There is provided a tooth extraction tool 1 comprising: a gripper 2; a shaft 3 extending from the gripper 2; and a head 4 at a tip of the shaft 3, where the head 4 is inserted into a periodontal space for performing tooth extraction by an action of a lever. The head 4 comprises: two protrusions 9, 10 which are bifurcated in plan view and extend in a direction separating from the shaft 3, the protrusions becoming sharp; and a web 11 which is between these protrusions 9, 10, for coupling the protrusions 9, 10, the web comprising a thin thickness which becomes hollow in an axial direction relative to tip ends of the protrusions 9, 10 and becomes hollow relative to the protrusions 9, 10 from both of a plane and a bottom surface in cross sectional view which is orthogonal to the shaft 3.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a tooth extraction instrument in dental medicine.

Background Art

[0002] Among tooth extraction instruments, those called Hebel or elevator in the dental industry have a gripper for manual gripping, a head to be inserted into the periodontal ligament cavity, and a shaft for connecting the gripper and the head to transmit force. By shaking the tooth root by the action of the lever and finally lifting the tooth root, it is an instrument for tooth extraction. This has the advantage that, unlike pliers, it can extract even teeth that are difficult to extract with only the tooth root remaining. The gripper is thickened for easy application of force and has various morphological improvements. The shaft is elongated so as to receive as little interference from others as possible. Commercially available tooth extraction elevators have a shape in which the tip of the head is round and swollen, and the center of the tip enters the deepest part of the periodontal ligament cavity. On the other hand, there has been proposed an improved commercially available elevator having a head in the shape of a U or V (Patent Document 1). This means that the tooth root can be sandwiched between the two protrusions of the head.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, whether using a shaking motion or a lifting motion, commercially available elevators, as described in Patent Document 1, have poor head engagement with the tooth root, causing slippage and resulting in prolonged tooth extractions that place a significant burden on the patient. Furthermore, even the elevator proposed in Patent Document 1 cannot tightly grip tooth roots of various sizes and shapes. Moreover, while the periodontal ligament space is curved circumferentially to surround the tooth root, the cross-section of the elevator is flattened, as described from the last line of page 4 to the second line of page 5 of the same document. As a result, the outer surface of the head, i.e., the belly and back, compresses the periodontal ligament and surrounding bone, often making insertion difficult. This necessitates using several different elevators to match the tooth's shape, leading to prolonged insertions and placing a burden on the patient. Therefore, the objective of this invention is to provide a tooth extraction device that can be applied to tooth roots of various sizes and shapes, and that can enable tooth extraction in a short time, thereby reducing the burden on the patient. [Means for solving the problem]

[0005] Therefore, the tooth extraction instrument of this invention is An instrument comprising a gripper, a shaft extending from the gripper, and a head at the end of the shaft, wherein the head is inserted into the periodontal ligament space and used to extract a tooth by lever action, The head is characterized by comprising two pointed protrusions that are bifurcated in a plan view and extend away from the axis, and a web that is located between the protrusions, connecting them, and has a thin wall thickness that is recessed in the axial direction from the tips of the protrusions and recessed from both the planar and bottom surfaces in a cross-sectional view perpendicular to the axis.

[0006] When using the tooth extraction instrument of this invention, grip the gripper and first insert the projection into the periodontal ligament space. Since the two projections are bifurcated, you may insert only one. They are pointed, making them easy to insert. Furthermore, even when inserting both projections into an irregularly shaped periodontal ligament space, you can easily insert them by interposing a protrusion of the periodontal ligament or bone between the first and second projections, thus avoiding interference with the protrusion. Moreover, since the web connects the projections, they will not break even if they are thin, and because the web is recessed axially from the tip of the projection and has a thin thickness that is recessed from both the flat and bottom surfaces, it can be inserted deeply without interference from a protrusion of the periodontal ligament or bone.

[0007] In either case, the second projection can be lifted using the first projection as a fulcrum and lever action. Typically, the second projection is then shaken around its axis using the first projection as a fulcrum. This widens the periodontal ligament space, making the work easier, and the tip moves deeper, gradually lifting the tooth root so that it can be extracted with less force. With the tooth extraction instrument of this invention, the first projection is embedded in the bone and the second projection in the periodontal ligament, allowing for shaking without slippage. Then, by using the first projection as a fulcrum and rotating the second projection widely while lifting it together with the tooth root, the tooth can be extracted.

[0008] The recess in the web in the direction intersecting the axis should deepen as it moves away from the axis on both the planar and bottom sides, and should be curved in a cross-sectional view perpendicular to the axis. This makes it easier to insert the head by aligning both the back and belly sides with the protrusions of the tooth root or bone. A preferred projection is one in which, in a plan view, the angle α formed by line a tangent to the outer shape line of the projection and line b tangent to the inner shape line, and in a front view, the angle β formed by line c tangent to the planar shape line of the projection and line d tangent to the bottom shape line, are both 30 degrees or less. By making it this sharp, the aforementioned insertion and biting action can be reliably achieved.

[0009] The two projections typically have a distance of 2 to 6 mm between their tips, a distance of 5 to 15 mm between the midpoint between their tips and the tip of the axis, and a distance of 2 to 7 mm between the midpoint and the tip edge of the web. Within this range, it is possible to apply to tooth roots of various sizes and shapes while maintaining the necessary strength.

[0010] Preferably, the shaft has a curved recess in a front view on the outer surface of the planar side connected to or near the head. By placing the index finger in this recess during insertion, medical accidents caused by inserting the instrument in the wrong place can be prevented, and less experienced dentists can learn the correct way to hold the instrument. The gripper preferably consists of a large-diameter body and a shoulder portion located between the body and the shaft, having a diameter intermediate between the diameter of the body and the diameter of the shaft, with the ridge on the flat side of the shoulder portion being chamfered. By placing the index finger on this chamfered portion during the lifting motion, medical accidents can be prevented, similar to the insertion motion, and the correct gripping technique can be easily learned. [Effects of the Invention]

[0011] As described above, the tooth extraction instrument of this invention has two pointed protrusions on its head, making it applicable to tooth roots of various sizes and shapes, and enabling tooth extraction in a short time, thereby reducing the burden on the patient. [Brief explanation of the drawing]

[0012] [Figure 1] The tooth extraction instrument of Embodiment 1 is shown, with (a) being a top view, (b) a front view, (c) a bottom view, (d) a left side view, and (e) a right side view. [Figure 2] This is a magnified plan view of the head of the tooth extraction instrument and its vicinity. [Figure 3] (a) is a cross-sectional view of AA' in Figure 2, (b) is a cross-sectional view of BB' in the same figure, (c) is a cross-sectional view of CC' in the same figure, (d) is a cross-sectional view of DD' in the same figure, (e) is a cross-sectional view of EE' in the same figure, (f) is a cross-sectional view of FF' in the same figure, and (g) is a cross-sectional view of GG' in the same figure. [Figure 4] This is a plan view illustrating the sharpness of the protrusions. [Figure 5] This is also a front view. [Figure 6] This is a perspective view showing the method of using the tooth extraction instrument of Embodiment 1, where (a) specifically shows the insertion operation and (b) specifically shows the shaking and lifting operations. [Figure 7] This is a horizontal cross-sectional view showing the tooth extraction instrument inserted into the periodontal ligament space. [Modes for carrying out the invention]

[0013] -Embodiment 1- As shown in Figure 1, the tooth extraction instrument 1 of the first embodiment is made entirely of a biocompatible, rust-resistant metal, such as stainless steel, cobalt-chromium alloy, or titanium alloy, and comprises a gripper 2, a shaft 3 extending linearly from the gripper 2, and a head 4 at the end of the shaft 3. The gripper 2 consists of a body 5 and a shoulder 6. The body 5 has a regular octagonal cross-section where it intersects with the shaft 3, with a length of approximately 6 cm in the axial direction, and is smoothly bulging in the middle section to a diagonal length of approximately 30 mm. The shoulder 6 is connected to the body 5, has a circular cross-section with a diameter of approximately 10 mm, and is approximately 15 mm long. The body 5 is hollow to reduce weight. The shaft 3 extends from the shoulder 6, and the edge of the shoulder 6 with respect to the shaft 3 on the planar side is chamfered 7. The shaft 3 has a circular cross-section, with a diameter of approximately 5 mm at its starting point where it connects to the shoulder portion 6. As it extends, it becomes thinner, reaching approximately 3 mm near the head 4. The outer surface of the flat side connected to the head 4 has a curved recess 8 with a depth of approximately 1 mm when viewed from the front.

[0014] The head 4 is bent approximately 30 degrees toward the bottom side with respect to the axis 3 in a front view, and forms a U-shaped or V-shaped symmetrical shape in a plan view around the axis as shown in Fig. 2, and integrally includes two protrusions 9, 10 and a web 11. The protrusions 9, 10 are bifurcated in a plan view and each extend in a direction away from the axis 3 and have pointed tips. The distance between the protrusions 9, 10 becomes larger toward the tips, and the distance between the tips is 4 mm. The web 11 is located between the protrusions 9, 10 and connects the protrusions to each other, just like the interdigital webbing between fingers for example, and has a thin wall thickness recessed from both the plane and the bottom surface in a cross-sectional view perpendicular to the axis 3 as shown in Fig. 3, compared to the protrusions 9, 10. The recesses on both sides of the web 11 become deeper as they move away from the axis 3, and are curved in a cross-sectional view perpendicular to the axis 3. Also, the distance between the midpoint between the tips of the protrusions 9, 10 and the tip of the axis 3, that is, the starting point of the web 11, is 10 mm, and the distance between the midpoint and the leading edge of the web 11 is 3 mm.

[0015] When the angle formed by a line b that contacts the inner shape line of the protrusion 9 and a line a that contacts the outer shape line of the protrusion 9 in a plan view as shown in Fig. 4 is α, and the angle formed by a line d that contacts the bottom surface shape line and a line c that contacts the plane side shape line of the protrusion 9 in a front view as shown in Fig. 5 is β, the protrusion 9 is sharper as both α and β are 30 degrees or less. The same applies to the protrusion 10.

[0016] When using the tooth extraction instrument 1, wrap the body part 5 with the palm, pinch the shoulder part 6 with the thumb and middle finger, and hold the gripper 2 as shown in Fig. 6(a) by placing the index finger F against the recess 8. First, insert the protrusions 9 and 10 into the periodontal ligament cavity, that is, the gap between the tooth root T and the alveolar bone B, and let the protrusion 9 bite into the tooth root T and the protrusion 10 bite into the alveolar bone B. Since they are pointed, they are easy to insert. Moreover, since the index finger F is placed against the recess 8 continuous with the head 4, it is easy to move the head 4 accurately. As a result, even if it is about to slip and advance to a part different from the part where it should bite in, it can be stopped with the index finger, preventing a medical accident of inserting it into the wrong place. Also, even when inserting two into a distorted periodontal ligament cavity, as shown in Fig. 7, by interposing a convex part of the tooth root or bone between the protrusion 9 and the protrusion 10, interference of the convex part can be avoided and it can be easily inserted. And since the web 11 connects the protrusions 9 and 10, each protrusion will not break even if it is thin. Moreover, since the web 11 is recessed in the axial direction from the tips of the protrusions 9 and 10 and recessed from both the plane and the bottom surface, it can be inserted deeply without being interfered by the convex part of the periodontal ligament or bone.

[0017] Next, with the protrusion 9 inserted at a position far from the center of the tooth root as a fulcrum, shake the protrusion 10 at a position close to the center of the tooth root around the axis as shown by the arrow X in Fig. 6(b). As a result, the periodontal ligament cavity expands and it becomes easier to work, and at the same time, the tooth root T gradually floats and can be removed with a small force. Since the protrusion 9 bites into the bone B and the protrusion 10 bites into the tooth root T, the protrusions 9 and 10 can be shaken surely without slipping with respect to the bone B and the tooth root T. Then, while rotating the protrusion 10 greatly with the protrusion 9 as a fulcrum as it is, lift it together with the tooth root by the action of the lever as shown by the arrows Y and Z in Fig. 6(b) to extract the tooth.

[0018] As described above, according to the tooth extraction instrument 1, both the shaking operation and the lifting operation can be performed with one tooth extraction instrument 1, so there is no need to replace the instrument for each operation. Also, in either operation, the pointed protrusions 9 and 10 bite into the tooth root T or the alveolar bone B, so there is no slippage. As a result, the tooth can be extracted in a short time. Furthermore, since the two protrusions 9 and 10 are bifurcated, in some situations, such as when the tooth root T is already quite loose, it is possible to insert only one from the beginning. Also, when lifting, by placing the index finger F on the chamfered part 7, it becomes easier to gradually lower the gripper 2, preventing medical accidents such as fractures caused by trying to abruptly extract a tooth root that is not sufficiently loose. Moreover, in this embodiment, since the head 4 is bent at approximately 30 degrees toward the bottom side with respect to the axis 3 when viewed from the front, it can also be used by inserting the head 4 into the periodontal ligament space on the other side of the tooth so that the front of the head 4 faces the alveolar bone and the bottom surface faces the periodontal ligament.

[0019] -Embodiment 2- The tooth extraction instrument of the second embodiment is identical in shape and material to the first embodiment, except that the distance between the tips of the projections is 3 mm, the distance between the midpoint between the tips of the projections and the tip of the shaft is 5 mm, and the distance between the midpoint between the tips of the projections and the tip edge of the web is 2 mm, and is suitable for teeth with a small diameter of root cross-section. [Explanation of Symbols]

[0020] 1. Tooth extraction instrument 2 Grippa 3 axes 4 heads 5 Torso 6 Shoulder 7. Chamfering 8. Dent 9, 10 protrusions 11 Web

Claims

1. An instrument comprising a gripper, a shaft extending from the gripper, and a head at the tip of the shaft, the head being inserted into a periodontal cavity to extract a tooth by lever action, The head includes two pointed protrusions that are bifurcated in a plan view and extend in a direction away from the axis, and a thin web that is located between the protrusions and connects the protrusions to each other, is recessed in the axial direction from the tips of the protrusions, and is recessed from both the top and bottom surfaces more than the protrusions in a cross-sectional view perpendicular to the axis, A tooth extraction instrument, characterized in that the shaft has a curved recess in a front view on an outer surface of a flat side that is connected to the head or is close to the head.

2. The tooth extraction instrument of claim 1, wherein the recesses in the web in a direction intersecting the axis become deeper on both the top side and the bottom side as they move away from the axis, and are curved in a cross-sectional view perpendicular to the axis.

3. The tooth extraction tool according to claim 1, wherein an angle α between a line a tangent to the outer shape line of the protrusion in a plan view and a line b tangent to the inner shape line, and an angle β between a line c tangent to the shape line on the planar side of the protrusion in a front view and a line d tangent to the shape line on the bottom side, are all 30 degrees or less.

4. The tooth extraction instrument of claim 1 or 2, wherein the two protrusions each have a distance of 2-6 mm between their tips, a distance of 5-15 mm between the midpoint between their tips and the tip of the shaft, and a distance of 2 to 7 mm between the midpoint and the tip edge of the web.

5. 2. The tooth extraction instrument of claim 1, wherein the gripper comprises a body portion having a large diameter, and a shoulder portion between the body portion and the shaft and having an intermediate diameter between the diameter of the body portion and the diameter of the shaft, and a ridge line on a flat side of the shoulder portion is chamfered.

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