WO2023152770A1

WO2023152770A1 - Dental implant design with enhanced surface area, torque resistance and improved stress dissipation to bone

Info

Publication number: WO2023152770A1
Application number: PCT/IN2023/050140
Authority: WO
Inventors: Dr. Vakil SINGH; Dr. Sk SINHA; Dr. Monika BANSAL; Dr. Kausik CHATTOPADHYAY; Dr. Rajesh BANSAL
Original assignee: Banaras Hindu University
Priority date: 2022-02-12
Filing date: 2023-02-11
Publication date: 2023-08-17
Also published as: WO2023152770A4; WO2023152770A9

Abstract

The present invention is describing an implant design which incorporates a dental implant with hexagonal/octagonal/square tunnel or cylinder with Hat wall along the central axis of implant for collecting bone chips, blood, osteoblasts during implant insertion where bone will grow and form 'locking block of bone" with far more potential to resist the rotational torque/couple force, rather than grooves on outside periphery. Further, this tunnel increases the overall surface area of the implant and metal gets replaced by vital bony tissue. Therefore, the present invention focuses on implant design which provides increased surface area of bone-to-implant contact, improving load transmission and accommodating resistance to torque forces.

Description

TECHNICAL FIELD

The present invention generally relates to dental implants device. More specifically, the present invention relates to a dental implant design provided with a tunnel along the central axis of implant.

BACKGROUND OF THE INVENTION

As age of human increase the number of teeth loss also increases due to dental caries and periodontitis along with age related senile and degenerative changes. From a biological point of view, replacement of a missing tooth with an implant is a much better modality as compared to conventional removable and fixed bridges. For rehabilitation with implant-prosthesis, a tapered screw is inserted (screwed) in the jaw bone after drilling a hole and allowed to heal/integrate to bone for 3-6 months, followed by crown/prosthesis attachment to the head of the implant and it functions more or less like a natural tooth.

Dental implants have become very popular among patients and clinicians due to success rate of more than 90% after long term use: however, these ail/fail in certain sites which have poor bone in terms of quality and quantity or heavy occlusal load situation. Short and thin implants with overall less surface area provide relatively less anchorage and soft bone (e.g., osteoporosis) further compromises the situation.

There are various challenges related to dental implants which act like root of an artificial tooth that is placed in the jaw bone to hold the prosthesis that replaces the missing tooth. Per-Ingvar B nine mark, "father of Morden dental implantology" and his team developed general technique ‘Osseointegration’ for titanium dental implants in 1960's and used titanium for the first time for dental implant in human teeth (https://en.wikipedia.org/wiki/Per-Ingvar_Branemark). Osseointegration is the direct apposition of bone on implant surface for formation of direct interface between living bone and an implant, without intervening soft tissue, and load- bearing surface ("loadbearing" as defined by Albrektsson et al. in 1981) artificial implant. The implant must be done with biocompatible materials like titanium to replace the natural root and reduce the rate of rejection. US patent US5533898A relates to a dental implant device for mounting prosthesis and minimizing the lodging of extraneous substances in interstitial spaces. A root form implant fixture is permanently implanted in a user's jaw bone. The fixture includes anchorage and engagement sections. The engagement section includes a cylindrical portion adjacent to the anchorage section, a bevelled portion that is adjacent to and coaxially disposed with respect to the cylindrical portion and a hexagonal portion adjacent to and coaxially disposed with respect to the bevelled portion.

WO201 1068432A I document relates to the dental implant for prosthetic dentistry comprises a root portion in the form of an element having an elongated shape and a blind hole, and an abutment in the form of a rod with a noncircular cross section which is inserted into the cavity of the blind hole, with one end of a coiled compression spring which is arranged in the cavity of this hole being fixed to the base of said abutment. The blind hole is formed with a cross section which repeats the cross section of the rod, said rod having, on the end which interacts with the coiled spring, a spherical head with a diameter greater than the transverse dimension of the rod, wherein a depression with a spherical shape is formed in the wall of the blind hole in the root portion, with this depression being in response to the spherical head of the rod and having a height greater than the height of the spherical head of the rod in order to provide for the axial movement of this rod over the section of the depression with a spherical shape and to provide for angular shift.

Prior document Implant design and stress distribution, Preeti Yadav et al. is a review literature related to the Implant design refers to the three-dimensional structure of the implant, with all the elements and characteristics that compose it. Implant function to transfer occlusal loads to the surrounding biologic tissues, functional design objectives should aim to manage biomechanical loads to optimize the implant - supported prosthesis function. Implantation system may increase or decrease the risk of screw loosening, crestal bone loss, implant body loss, peri-implantitis. esthetics of soil tissue drape, implant failure, and implant body fracture. This article related to help the learner in making a judicious informed decision regarding the different factors governing the reduction of overall stress in implant fixtures and thus, providing a better treatment to their patients. Morse taper is being used in some dental implants (Bicon) however they lack the hexagonal component below this which can be used for generating the torque for tapping the implant into the osteotomy, t hese are simply pushed into the osteotomy rather than screwing in to achieve primary stability due to engagement of threads into the bone by applying high torque (30-60 N-cm).

The dental implants arc used to replace missing teeth and provide support, stability and retention to the prosthesis. These implants transfer the occlusal loads to the surrounding jaw bone. The design of these cylindrical screw shaped dental implant design has to consider insertion torque, stability, and force distribution/dissipation to bone, correction resistance, fatigue resistance, resist complex compound forces and biocompatibility.

Adell et al were the first to measure the CBL in the 1 year of prosthetic loading. Albrektsson el al observed that the two-piece implants when placed sub-crestally in the bone resulted in CBL of 1.5-2.0 mm after 1 year of loading. At the Toronto Conference CBL around the implant of nearly 2 mm in the 1^st year of function is acceptable, and is considered successful. Various Methods to prevent and minimize the effects of crestal bone loss include sufficient bone around implants in all directions, wider diameter of bone, maintaining the inter-implant distance, low implant insertion torque, biological width and platform switching.

Jung RE et al. mentions abutment-screw loosening is a major complication that alone accounts for up to 33% of all implant related complications. Moberg LE et al stated based on literature the incidence rate of abutment screw loosening reaches 5.3% one year post loading and 5.8%- 12.7% five year post loading. Most of the times this problem remains unnoticed to the patients and this problem gets worsened with time leading to thread distortion or screw/implant fracture. Types of implant abutment connection, preload, design and material of abutment as well as screw, design and number of implants, patient and prosthesis are the major factors affecting abutment screw loosening. Reducing the cantilever, optimum preload, internal implant-abutment connection, screw retightening after 5 to 10 minutes, following implant protected occlusal scheme, anti-rotation feature are the methods that play pivotal role in preventing abutment/screw loosening. The contemporary dental implants address these issues, although, constant growth is required for the improvement. The success of dental implants depends not just on materials and mechanical principles but biology of tissues and biomechanics are main drivers for the survival of the implants.

OBJECTIVES OF THE INVENTION

The preferred objective of the present invention is to provide a dental implant with hexagonal/octagonal/square shape tunnel or cylinder with a flat wall along the central axis of implant and wherein the tunnel increases the overall surface area of the implant.

Another objective of the present invention is to design a dental implant where bone will grow and form ‘locking block of bone’ with far more potential to resist the rotational torque/couple force.

Yet another objective of the present invention is to provide the block of bone in central axis help in transmission of compressive loads to bone and becomes a great help in short implants with less than 8 mm height or reduced bone density.

A further objective of present invention is to provide dental implant which is often made of titanium, and possess modulus of elasticity (MoE) higher than the bone. In present design the modulus of elasticity is closer to the bone for better interface survival.

These and other objectives of the present invention will be apparent from the descriptions herein. Every objective of the invention is attained by at least one embodiment of the present invention.

SUMMARY OF THE INVENTION

The present invention is describing an implant design which incorporates a dental implant with hexagonal/octagonal/square tunnel or a flat wall cylinder along the central axis of implant for collecting bone chips, blood, osteoblasts during implant insertion where bone will grow and form ‘locking block of bone’ with far more potential to resist the rotational torque/couple force, rather than grooves on outside periphery. Further, this tunnel increases the overall surface area of the implant and metal gets replaced by vital bony tissue.

The implant body design help in transmitting the occlusal load to the bone. Compressive loads are better for the health of surrounding jaw bone than the tensile or shear loads. These potentially dangerous tensile and shear forces in dental implants may be controlled by careful designing of implants. The apical part of the dental implants has a tapered geometry which helps easy insertion into the osteotomy and initial engagement to the bone.

In addition, the apical region of implants usually has small ditches, slots, grooves, flat surfaces, holes or vent on outside periphery of implant for the bone to grow into and increase resist against torque forces.

These features which are circumferentially arranged on the implant body assist implant in resisting rotation by torque/ couple and help insertion of implant. Thus, the present implant design is helpful in increasing overall bone to implant contact, improved load transmission and resistance to torque forces.

Therefore, the present invention focuses on implant design which provides the increase in the surface area of bone-to-implant contact, improving load transmission and accommodating resistance to torque forces which shows novelty and technical advancement in modern dentistry area.

Further novel and inventive features of the present invention would be more apparent with the drawings and illustrations of the implant design of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 , is a perspective view of an embodiment of implant body and abutment design.

Figure 2. is a preferred component comprising of an embodiment of machined implant and abutment.

Additional objects, method and advantages of the present invention will become more apparent from following detailed description of preferred embodiments. DETAILED DESCRIPTION OF THE INVENTION

The Following is a detailed description of embodiments of the disclosure illustrated in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the above-mentioned prior art documents generally relate to dental implants device used for replacement of a missing tooth with an implant.

The success of dental implants depends not just on materials and mechanical principles but biolog) of tissues and biomechanics as well. These are the main factors responsible for the survival of the implants. The implant body design help in transmitting the occlusal load to the bone.

Implants transfer the occlusal loads to the surrounding jaw bone with maximum stress in crestal region i.e., the entry point into bone and implants usually suffer with crestal bone loss (CBL) which is 2^nd most common problem related to dental implants. The modulus of elasticity (MoE) of the implant & bone are not same and titanium has almost five times more MoE than bone. thus, it is a compromise due to stress shielding and once load is applied in one direction it tries to compress bone in that direction and produce tension in other side of bone-implant interface, trying to create gaping.

The design of the cylindrical screw shaped dental implant has to consider insertion torque, stability, force distribution/dissipation to bone, corrosion resistance, fatigue resistance, resist complex compound forces and biocompatibility. The contemporary dental implants address all these issues, although, constant growth is required for better long term success and avoiding aforesaid complication/failure. The implant body design help in transmitting the occlusal load to the bone and compressive loads are better for the health of surrounding jaw bone than the tensile or shear loads.

These potentially dangerous tensile and shear forces in dental implants may be controlled by careful designing of implant. The apical region of implants usually has small ditches, slots, grooves, flat surfaces, holes or vents on outside periphery for the bone to grow into these features and help in resisting against tensile, shear and torque forces. In the preferred embodiment of the present invention, there is described an implant design which rather than having grooves oonn outside periphery, incorporates a hexagonal/oclagonal/square tunnel or a flat wall cylinder along central axis of implant.

This tunnel helps for collecting bone chips, blood, osteoblasts during implant insertion where bone will grow and form "locking block of bone" with far more potential to resist the rotational torque/couple force. Moreover, this tunnel increases the overall surface area of the implant and metal gets replaced by vital bony tissue.

This block of bone present in central axis helps in transmission of compressive loads to bone and becomes a great help in short implants with less than 8mm height or reduced bone density. The final stability of a dental implant mainly depends on the bone-to- implant interface, more the bone is formed, more it will be. As stated above MoE of the implant (titanium) is almost five times more than bone, thus it is a compromise due to stress shielding which will be minimized by presence of this tunnel (making implant tube like) filled by bone in long axis.

Bone is a vital/living mineralized tissue like a composite of minerals and an organic material supplied by blood vessels/ncrves and is in dynamic equilibrium with blood. The modulus of elasticity (MoE) of the implant and bone are never same and titanium has almost five times more MoE than bone, thus it is a compromise due to stress shielding which will be minimized by presence of this tunnel filled by bone in long axis. Thus, present implant design has potential to perform better in compromised bone quality and quantity sites by increasing overall bone to implant contact, improved load transmission and resistance to torque forces.

Figure 1 of the present invention is describing an implant body and abutment design as described below:

A. Hexagonal tunnel in apical part for implant insertion and bone growth after installation in bone.

B. Tapered female housing for friction fit of corresponding tapered male abutment extension C. Threaded body of cylindrical implant: the thread shape, pitch, depth etc can change as per substrate.

D. Tapered male abutment extension for friction fitting at top of implant body having female corresponding conical concavity

E. Part of abutment which extends into oral cavity and help in attachment of prosthesis/crown. Dimensions can vary as per clinical situation.

Figure 2 of the present invention is describing a machined implant and abutment showing different features as below:

F. Abutment; size/shape may be altered as per clinical situation

G. Cylindrical implant with threads

H. Male and female component of abutment and implant body are friction fitted together

I & J. Implant with hexagon at its bottom for bone growth

Thus, present implant design is helpful in increasing initial stability, overall bone to implant contact, improved load transmission and resistance to torque forces.

ADVANTAGES OF THE INVENTION

1. The dental implant of the present invention is advantageous in reducing the rotational torque/couple force because of the presence of a tunnel along the central axis.

2. This tunnel increases the overall surface area of the implant and metal gets replaced by vital bony tissue.

3. The present implant design has potential to perform better in compromised bone quality and quantity sites by increasing overall bone to implant contact, improved load transmission and resistance to torque forces. 4. The modulus of elasticity (MOE) for this implant is lower than the solid screw shaped device, thus it decreases the disparity in metal and bone in terms of MOE.

Claims

WE CLAIM:

1. A dental implant comprising of an apical region and a root region, characterized in that: the apical region possesses tapered geometry having a tunnel (A) with Hat wall along with the central axis for Implant insertion and bone growth: the root part having a tapered female housing (B) for tapering with male abutment extension (D): and wherein part of abutment extends into oral cavity and help in attachment of prosthesis/crown.

2. The dental implant as claimed in claim I, wherein the provision of tunnel is for collecting bone chips, blood and osteoblasts during implant insertion and wherein the said tunnel increases the overall surface area of implant and the metal gets replaced by vital bony tissue.

3. The dental implant as claimed in claim 1. wherein the male and female component of abutment and implant body are friction fitted together.

4. The dental implant as claimed in claim I. wherein the bone forms locking block of bone with far more potential to resist the rotational torque/couple force.

5. The dental implant as claimed in claim I. wherein the said block of bone in central axis transmits the compressive loads to bone and helps in short implants with less than 8 mm height or reduced bone density.

6. The dental implant as claimed in claim I. wherein the said dental implant possess modulus of elasticity (MoE) closer to the bone for better interface survival.

7. The dental implant as claimed in claim 1. wherein the bone-bone implant interface provides stability to the dental implant.

Dated this 02^nd day of February. 2023