Short implant for dental department

Abstract

The invention relates to a dental short implant, and belongs to the technical field of medical instruments. The implant comprises a main body, the lower part of the main body is a fixing part, the upper part of the main body is a connecting part, the upper side of the fixing part is provided with a composite thread consisting of a sawtooth-shaped counterfort thread and a sawtooth-shaped reverse counterfort thread, a pressure surface is formed between the sawtooth-shaped counterfort thread and the sawtooth-shaped reverse counterfort thread, the lower side of the fixing part is a V-shaped thread, and the bottom of the fixing part is a circular truncated cone; and the fixing part and the connecting part are integrally formed and manufactured. The invention aims to be applied to cases of bone mass insufficiency in maxillary sinus areas or near mandibular nerve tube parts, prevent a central screw from being broken and loosened, and overcome the problem of inflammation caused by a micro gap between an abutment and an implant.

Description

Technical Field

[0001] This invention relates to a short dental implant, belonging to the field of medical device technology. Background Technology

[0002] Traditional dental implant surgery typically requires patients to have sufficient alveolar bone height to accommodate standard implants, usually 8 to 15 mm in length. However, many patients with missing teeth experience insufficient bone volume due to alveolar bone atrophy caused by long-term tooth loss, periodontal disease, or structural issues, especially in the posterior teeth region near the maxillary sinus or mandibular canal. In the past, such patients often required complex bone augmentation surgeries, such as maxillary sinus lifts or bone grafting, to receive implant restorations. These outcome-oriented surgeries not only increased treatment time, costs, and surgical trauma but also brought associated risks and complications.

[0003] To avoid the aforementioned problems, the design of short implants has emerged. Its core concept is to complete the implantation within a limited height by shortening the length of the implant, thereby minimizing or avoiding bone augmentation surgery and providing a more convenient and less invasive treatment option for specific patient groups.

[0004] Specific applications of short implants include avoiding the mandibular nerve canal in the area near the maxillary sinus or mandibular posterior teeth; patients who are unsuitable for or unwilling to undergo bone grafting surgery due to health conditions, personal wishes, or economic reasons; and simplifying the entire implant surgery process by avoiding bone grafting, shortening the healing period, and improving patient acceptance.

[0005] Despite the obvious advantages of short implants, there are still risks and disadvantages in clinical application: due to the shortened length of the implant, the total contact area between the implant and the bone tissue is reduced accordingly, which may affect its long-term stability and implant reliability to some extent. After the short implant is implanted, the length-to-width ratio of the crown and the implant is not coordinated, which increases the risk of lateral occlusal forces and has an adverse effect on the bone tissue around the implant.

[0006] The central screw of a short implant, acting as a crucial joint connecting the implant and abutment, presents numerous potential risks. Loosening of the central screw is the most common warning sign, and this risk is particularly pronounced for short implants. This is because: short implants are typically paired with longer crowns, resulting in a higher crown-to-root ratio. This excessive ratio creates a vertical cantilever structure, similar to a lever, amplifying the lateral forces (non-axial forces) generated during chewing and concentrating them on the central screw at the implant-abutment junction. Secondly, the screw's stability relies on the preload generated during tightening. This force ensures a tight fit between the abutment and implant; however, under continuous biting forces, especially amplified lateral forces, the preload gradually weakens, eventually leading to loosening.

[0007] Long-term loose central screws will repeatedly move slightly under functional loads, leading to metal fatigue. Eventually, a more serious complication than loosening will occur at the stress point: "screw breakage". Alternatively, due to improper biting habits of the patient, such as chewing hard objects and bruxism, the huge biting force generated may be amplified by the leverage force of a high crown-to-root ratio, which may instantly exceed the stress limit of the material and cause breakage.

[0008] The connection of the central screw is not completely sealed. Even when properly tightened, a micrometer-level gap may exist between the implant and the abutment. When the screw loosens, this micro-gap increases significantly. This increased gap becomes a breeding ground for bacteria. Bacteria and fluids from the oral cavity can enter the implant through this micro-gap, potentially causing halitosis and, in severe cases, peri-implantitis. Long-term inflammation can damage the alveolar bone around the implant, affecting the normal osseointegration between the implant and surrounding bone tissue. For short implants with limited bone volume, any form of bone damage will affect the long-term stability of the implant.

[0009] In summary, the risks associated with the central screw in short implants are closely related to the biomechanical environment. An increased crown-to-root ratio is a key challenge. When the abutment is designed separately and connected to the implant, the central screw acts as an amplifier, converting normal occlusal forces into potential destructive forces on the central screw, thus triggering the aforementioned series of chain reactions. Therefore, this invention is proposed. Summary of the Invention

[0010] To address the shortcomings of existing technologies, this invention provides a short dental implant designed for use in cases of insufficient bone volume in the maxillary sinus region or near the mandibular nerve canal. This prevents the central screw from breaking or loosening and overcomes inflammation caused by micro-gaps between the abutment and the implant.

[0011] The technical solution of the present invention is as follows: A short dental implant includes a main body, a fixing part at the bottom and a connecting part at the top. The upper side of the fixing part is provided with a composite thread composed of a sawtooth support thread and a sawtooth reverse support thread, and a pressure surface is formed between the sawtooth support thread and the sawtooth reverse support thread. The lower side of the fixing part has a V-shaped thread, and the bottom of the fixing part is a frustum. The fixing part and the connecting part are integrally formed.

[0012] The fixation unit is implanted into the alveolar bone and is responsible for achieving osseointegration and initial stability. Its threaded design is designed to maximize the osseointegration area and provide self-tapping capability.

[0013] According to a preferred embodiment of the present invention, the composite thread occupies 2 / 3 of the length of the side wall of the fixing part, and the V-shaped thread occupies 1 / 3 of the length of the side wall of the fixing part.

[0014] According to a preferred embodiment of the present invention, the connection between the fixing part and the connecting part is a transition platform. The transition platform is an arc-shaped surface convex towards the oral cavity. A recessed interface is provided inside the transition platform near the connecting part. The inner wall of the recessed interface is circular, and the outer wall is a petal-shaped structure composed of several arcs. Figure 5 As shown, the carrier's connection interface (hexagonal quincunx structure) matches the recessed interface.

[0015] According to a preferred embodiment of the present invention, the depth of the recessed interface is 1 mm to provide effective anti-rotation locking, and the radius of each arc on the recessed interface is 0.38 mm. The use of the recessed interface can strengthen the structure, disperse stress, and effectively prevent cracks from forming under torque.

[0016] According to a preferred embodiment of the present invention, the length of the fixing part is 5 mm, the fixing part is conical, the bottom diameter of the fixing part is 2.8 mm, the top diameter is 4.0 mm, and the diameter of the protrusion can be slightly increased to 4.2 mm to compact the cortical bone.

[0017] According to a preferred embodiment of the present invention, the composite thread and V-thread pitch in the fixation part is 0.9 mm to increase its initial stability in osteoporotic bone, and the thread helix angle is 4.8° to ensure the implantation efficiency and self-locking performance of the fixation part.

[0018] According to a preferred embodiment of the present invention, in the fixation part, the thread angle of the serrated buttress thread and the serrated reverse buttress thread is 23°, and the angle between their extensions is less than 60°, forming a sharper thread that helps to cut into the bone. The thread angle of the V-shaped thread is 30°, which allows the implant to cut out a thread channel on its own during implantation.

[0019] According to a preferred embodiment of the present invention, in the fixing part, the depth of the compound thread and the V-thread gradually becomes shallower from the bottom to the top.

[0020] According to a preferred embodiment of the present invention, the side wall of the connecting part is provided with threads (using standard mechanical V-type threads), the connecting part replaces the central screw structure connected to the base, the protruding thread connects with the internal thread of the base, and the bottom of the base is covered with a recessed interface after connection.

[0021] According to a preferred embodiment of the present invention, the length of the connecting part is 3mm, the thread on the connecting part is a single-start thread, and the axial advance is one pitch for one revolution, with a pitch of 0.6mm. The thread uses a finer pitch than that of the fixed part, providing stronger locking force and anti-loosening ability. The diameter of the connecting part is 1.5mm.

[0022] The beneficial effects of this invention are as follows: 1. The implant fixation and connection parts of this invention are integrally cast, replacing the central screw structure of the traditional short implant abutment. This represents a paradigm shift addressing the core drawbacks of traditional segmented implant systems. The integral design eliminates the weakest link in the mechanical connection. In traditional short implants, the central screw, with a diameter of only about 1mm, is the weakest link in the entire restoration when bearing the occlusal force. Due to the mismatch between the crown and root proportions of short implants, the leverage effect drastically amplifies the stress acting on the screw. By integrally casting, the central screw component is completely replaced. The force transmission is no longer a small screw, but a solid metal structure with a diameter larger than the screw and the same material as the implant. This results in a geometric increase in the resistance to metal fatigue and fracture resistance of the threaded structure of the connection part. This design fundamentally eliminates the risk of screw loosening and breakage. After the abutment is tightened, there will be no interface or gap between the implant and the abutment connection part, resulting in a continuous and seamless state. Therefore, the bacterial penetration problem caused by microleakage is completely solved.

[0023] 2. The integrated design of this invention greatly simplifies the clinical operation process. In the clinical application of traditional implants, doctors need to select, install, and tighten the abutment with a specific torque, and handle multiple small parts. This not only increases the complexity and time of the operation, but also introduces more potential error links. Due to the integrated design, the implant itself has a connecting part of the abutment, eliminating the steps of selecting and installing the abutment. After the implant is implanted, the doctor can directly perform an oral scan or take an impression, and then make the superstructure prosthesis. This not only reduces the number of visits and time for patients, but also saves the doctor's chairside operation time.

[0024] Furthermore, the integrated design optimizes the biomechanical transmission mode. In traditional implant applications, occlusal force is transmitted through the path of crown → abutment → central screw → implant. The force is highly concentrated on the tiny screw, causing huge stress on the screw and the threads of the implant neck. However, the integrated cast occlusal force is directly transmitted to the implant through a continuous integral structure. The abutment and implant are interconnected, and the force is evenly distributed to the surrounding bone tissue. The force transmission path is shorter, more direct and efficient, avoiding stress concentration at weak points. This is a huge biomechanical advantage for short implants that are already short.

[0025] 3. The connecting thread structure of this invention adopts a single-thread design, which has overwhelming advantages when connected to the abutment. It has excellent self-locking performance and anti-loosening ability. Because the thread helix angle of this invention is very small, it is simulated as a very gentle slope. According to mechanical principles, the gentler the slope, the less likely the object is to slide down the slope. Therefore, without external force to rotate it, it is almost impossible for the abutment or crown to vibrate and loosen from the upper thread structure. This is the first and most important line of defense against abutment loosening. Secondly, because the distance the abutment travels in one rotation is very short, the doctor can achieve very precise torque control when tightening the abutment with a torque wrench. This is very important for applying the correct preload. Sufficient preload can tightly compact the abutment and implant, eliminate micro-gaps, and thus prevent bacterial leakage and metal fatigue of the thread structure.

[0026] 4. The transition platform of this invention adopts an arc-shaped surface convex towards the oral cavity. Its advantages are mainly reflected in three aspects: biology, biomechanics, and prosthodontics. Its biological advantage lies in creating space for soft tissue and building a healthy gingival barrier. Traditional platform transfer refers to the abutment diameter being smaller than the implant platform. The above design goes a step further. Through a smooth convex surface, it moves the connection interface between the implant and the prosthesis away from the alveolar bone apex in both the horizontal and vertical directions, creating a large sterile space for the bone plane. Moreover, the smooth convex slope above provides additional attachment volume and growth space for gingival tissue. The gingiva can grow thicker and fuller on this slope, which is key to resisting bacterial invasion, preventing gingival recession, and maintaining long-term aesthetic results. Furthermore, because the connection interface and potential bacterial leakage are moved to a position away from the bone, the risk of alveolar ridge resorption caused by inflammatory cell infiltration is minimized, achieving optimal bone healing. Its biomechanical advantage lies in the smooth transmission of stress and protection of the cervical bone. The traditional implant platform is a 90° right angle, which is the part where the occlusal force is concentrated except for the central screw. The huge stress concentration is another important reason for cervical bone resorption. The convex bevel of this invention replaces the right angle with a smooth arc, which allows the occlusal force to be smoothly and evenly distributed to the implant body and the surrounding alveolar bone, avoiding destructive stress concentration. In addition, the convex bevel design converts part of the vertical occlusal force into lateral compressive stress on the bone. Moderate compressive stress is beneficial to bone remodeling and maintaining bone mass.

[0027] Its restorative advantage lies in guiding a natural aesthetic contour, especially when applied to the anterior aesthetic zone. This sloping, curved surface provides a perfect transition guide for dental technicians to fabricate crowns. The crown can emerge from the gum line with a very natural, full curve from this platform, perfectly mimicking the natural tooth shape and achieving optimal aesthetic restoration results. This seemingly simple curved transition platform can be considered a culmination of design, a highlight of this invention. Unlike traditional implants that passively encroach on bone and gum space, it actively designs a healthier, more stable, and more aesthetically pleasing environment for both soft and hard tissues.

[0028] 5. The core advantage of the recessed interface of this invention lies in its complete separation of implantation force and repair surface, protecting the absolute integrity of the repair structure. In existing implants, the interface of the carrier and the connection interface of the final abutment are the same or very close. During implantation, a huge torque needs to be applied, and this force will directly act on the precision structure at the top of the implant. This can easily lead to damage to the repair interface and contamination of the repair platform by blood, saliva, and bone fragments during implantation, ultimately affecting the tightness of the abutment. The recessed interface cleverly avoids the upper connection structure, moving the drive interface that bears the torque downward to the more robust and thicker lower fixation part. The threaded structure of the connection part is completely unloaded. Therefore, no matter how much force is applied during implantation, it completely bypasses the precision threads at the top. After the implant is in place, what is presented to the doctor is a brand-new, undamaged repair platform.

[0029] Furthermore, the recessed interface extends deep into the lower fixation part, meaning it has sufficient depth. This allows the carrier to be deeply and stably attached to the implant, forming a whole. This prevents any form of shaking or slippage during implantation, allowing doctors to easily control the depth and angle of implantation.

[0030] 6. The thread design of the fixation part of the present invention is a progressive thread and a self-tapping design. The depth of the thread gradually becomes shallower from the root tip to the neck, and the core diameter gradually increases to form a cone shape. During implantation, it can gently compress the bone and produce a compression effect, increasing initial stability. The deeper thread and sharp cutting edge allow the implant to cut out the thread channel itself during implantation.

[0031] The asymmetric thread structure, which combines the sawtooth buttress thread, the sawtooth reverse buttress thread, and the pressure surface between the two, utilizes its inclined surface to convert the force into compressive stress on the alveolar bone when implanting the implant or bearing occlusal forces, while using the vertical surface to bear the huge axial force from the same direction, resisting the screwing in or removal of the implant. Furthermore, when cutting bone, it can remove bone fragments and store them between adjacent threads, providing good initial preparation for osseointegration.

[0032] The V-shaped thread structure of the fixation part reaches the root apex region of the bone first at the moment of implantation, usually located in the cancellous bone region within the jawbone. When the sharp edge of the V-shaped thread is screwed in, it will produce a cutting and squeezing effect on the surrounding trabecular bone structure, achieving immediate mechanical locking. This is the key to obtaining high initial stability and can resist any micro-movement after implantation.

[0033] Deep thread design can increase the bone integration area. The deeper the thread, the larger the unfolded surface area, which means more space for osteoblasts to climb, grow and deposit bone matrix, resulting in a higher bone integration strength.

[0034] 7. Application scope of the implants of this invention: Severe bone height deficiency in the posterior region, such as less than 8mm from the alveolar ridge crest to the mandibular nerve canal in the mandibular posterior region, and less than 6-7mm from the alveolar ridge crest to the maxillary sinus floor in the maxillary posterior region; Patients who have contraindications or resistance to additional bone grafting surgery, such as those who cannot undergo bone grafting surgery due to age or systemic diseases, or those who refuse bone grafting due to fear of surgical trauma, long healing period, or high cost; Cases with extremely high mechanical strength requirements, such as bruxism, clenching teeth, or single missing posterior teeth; Cases with thin and easily receding gingiva and a pursuit of ultimate soft tissue aesthetics; Cases that pursue immediate or early loading. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a cross-sectional schematic diagram of the present invention; Figure 3 This is a schematic diagram of the implantation of the present invention into the patient's oral cavity and the connection of the matching abutment; Figure 4 A schematic diagram of the cross-section of the base that is compatible with this invention; Figure 5 This is a top view schematic diagram of the implant of the present invention; Figure 6 Schematic diagram of the connection of the carrier for the present invention; Where: 100, main body; 110, connecting part; 120, concave interface; 130, fixing part; 140, base; 150, carrier; 121, transition platform; 131, serrated buttress thread; 132, pressure surface; 133, serrated reverse buttress thread; 134, V-shaped thread; 135, frustum; 141, internal thread; 151, hollow cylinder; 152, plum blossom interface. Specific embodiments

[0036] The present invention will be further described below through embodiments in conjunction with the drawings, but not limited thereto.

[0037] Embodiment 1: As Figure 1-6 shown, this embodiment provides a short dental implant, including a main body 100. The lower part of the main body 100 is a fixing part 130, and the upper part is a connecting part 110. The upper side of the fixing part 130 is provided with a composite thread composed of a serrated buttress thread 131 and a serrated reverse buttress thread 133. A pressure surface 132 is formed between the serrated buttress thread 131 and the serrated reverse buttress thread 133. The lower side of the fixing part 130 is a V-shaped thread 134, and the bottom of the fixing part 130 is a frustum 135. The fixing part 130 and the connecting part 110 are integrally formed. The main body 100 is made of medical-grade grade 5 titanium alloy (Ti-6Al-4V ELI, Grade 5 ELI), which has good mechanical properties, with a tensile strength ≥ 930 Mpa and a yield strength ≥ 860 Mpa.

[0038] The fixing part is implanted into the alveolar bone, responsible for achieving osseointegration and initial stability. Its thread design aims to maximize the osseointegration area and provide self-tapping properties.

[0039] The composite thread occupies 2 / 3 of the length of the side wall of the fixing part, and the V-shaped thread 134 occupies 1 / 3 of the length of the side wall of the fixing part.

[0040] The connection between the fixing part 130 and the connecting part 110 is a transition platform 121. The transition platform 121 is an arc-shaped surface convex towards the oral cavity. Inside the transition platform 121, a concave interface 120 is provided close to the connecting part. The inner side wall of the concave interface 120 is circular, and the outer side wall is a petal-shaped structure composed of several arcs. As Figure 5 shown, the carrier 150 adopts a hollow cylinder 151, and the connection interface of the carrier (plum blossom interface 152) matches the concave interface.

[0041] The recessed interface 120 has a depth of 1 mm to provide effective anti-rotation locking. The radius of each arc on the recessed interface 120 is 0.38 mm. The recessed interface 120 can strengthen the structure, disperse stress, and effectively prevent cracks from forming under torque.

[0042] The length of the fixation part 130 is 5mm. The fixation part 130 is conical. The bottom diameter of the fixation part 130 is 2.8mm, the top diameter is 4.0mm, and the diameter of the protrusion can be slightly increased to 4.2mm to compact the cortical bone.

[0043] In the fixation part 130, the pitch of the composite thread and the V-type thread 134 is 0.9mm, which increases its initial stability in osteoporotic bone, and the thread helix angle is 4.8°, which ensures the implantation efficiency and self-locking performance of the fixation part.

[0044] In the fixation part, the thread angle of the serrated buttress thread 131 and the serrated reverse buttress thread 133 is 23°, and the angle between their extended lines is less than 60°, forming a sharper thread that helps to cut into the bone. The thread angle of the V-shaped thread 134 is 30°, which allows the implant to cut out a thread channel on its own during implantation.

[0045] In the fixing part 130, the depth of the compound thread and the V-shaped thread 134 gradually becomes shallower from the bottom to the top.

[0046] The connecting part 110 has threads (using standard mechanical V-type threads) on its side wall. The connecting part replaces the central screw structure that connects to the base, and the threaded part extends outward to connect with the internal thread 141 of the base. After the base is connected, the bottom is covered with a recessed interface.

[0047] The length of the connecting part 110 is 3mm. The thread on the connecting part 100 is a single-start thread, which advances one pitch axially with one rotation. The pitch is 0.6mm. It uses a finer pitch than the thread on the fixed part, providing stronger locking force and anti-loosening ability. The diameter of the connecting part is 1.5mm.

[0048] Working principle: In clinical use, the implant cavity is prepared using an existing drilling machine. Then, the implant carrier 150 is inserted into the recessed interface 120. The carrier must be fully in place. First, a machine wrench with a torque of 25N is used for insertion. Then, a hand wrench is used to apply force to 35N. The sign that the implant is fully in place is that the widest part of the implant diameter is flush with the alveolar bone surface. The recommended insertion torque for the implant is 35-45N·cm, and it can withstand an insertion torque of up to 60N·cm. After the implant is fully in place, the abutment 140 is screwed in. The bottom of the abutment 140 is completely sealed with the transition platform 121 and completely covers the recessed interface 120.

[0049] While the preferred embodiments of the present invention have been described above, the scope of the present invention is not limited to these specific embodiments. Those skilled in the art can make appropriate modifications within the scope set forth in the patent claims of the present invention.

Claims

1. A short dental implant, characterized in that, The device includes a main body, with a fixed part at the bottom and a connecting part at the top. The upper side of the fixed part is provided with a composite thread consisting of a sawtooth support thread and a sawtooth reverse support thread. A pressure surface is formed between the sawtooth support thread and the sawtooth reverse support thread. The lower side of the fixed part has a V-shaped thread, and the bottom of the fixed part is a frustum. The fixed part and the connecting part are integrally formed.

2. The short dental implant as described in claim 1, characterized in that, The compound thread occupies 2 / 3 of the length of the side wall of the fixed part, and the V-shaped thread occupies 1 / 3 of the length of the side wall of the fixed part.

3. The short dental implant as described in claim 1, characterized in that, The connection between the fixing part and the connecting part is a transition platform. The transition platform is an arc-shaped surface. A recessed interface is provided inside the transition platform near the connecting part. The inner wall of the recessed interface is circular, and the outer wall is a petal-shaped structure composed of several arcs.

4. The short dental implant as described in claim 3, characterized in that, The recessed interface has a depth of 1mm, and the radius of each arc on the recessed interface is 0.38mm.

5. The short dental implant as described in claim 1, characterized in that, The length of the fixing part is 5mm, the fixing part is conical, the bottom diameter of the fixing part is 2.8mm, and the top diameter is 4.0mm.

6. The short dental implant as described in claim 1, characterized in that, In the fixed part, the pitch of the compound thread and the V-type thread is 0.9mm, and the thread helix angle is 4.8°.

7. The short dental implant as described in claim 1, characterized in that, In the fixed part, the screw angle of the sawtooth support type thread and the sawtooth reverse support type thread is 23°, the intersection angle of their extension lines is less than 60°, and the screw angle of the V-type thread is 30°.

8. The short dental implant as described in claim 1, characterized in that, In the fixed part, the depth of the compound thread and the V-shaped thread gradually becomes shallower from the bottom to the top.

9. The short dental implant as claimed in claim 1, characterized in that, The connecting part has threads on its side wall.

10. The short dental implant as claimed in claim 9, characterized in that, The length of the connecting part is 3mm, the thread on the connecting part is a single-start thread, and the axial advance is one pitch for one revolution. The pitch is 0.6mm, and the diameter of the connecting part is 1.5mm.

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