阅读说明：本技术 用于在牙齿结构中安装螺钉的铣削工具 (Milling tool for mounting screws in dental structures ) 是由 艾萨克·库拉纳·德·阿科斯 罗伯特·冈萨雷斯·塞加拉 于 2019-08-07 设计创作，主要内容包括：一种用于在牙齿结构中安装螺钉的铣削工具,所述螺钉预计用于附接至牙齿种植体,其中,该工具包括耦接区段和工作区域,耦接区段预计用于将其耦接至钻头,工作区域由杆限定,杆在其一端处支撑头部,头部具有相对于耦接部分的纵向轴线径向分布的多个切削刀片,其中,每个切削刀片均呈现下切削面。所述下切削面呈现具有凸形曲率的区域,该凸形曲率具有在最大值与最小值之间变化的半径,该半径的最大值等于0.1350*Dh,其中,Dh对应于铣削工具的有效区域的直径,并且该半径的最小值满足以下公式：(A milling tool for mounting a screw in a dental structure, said screw being intended for attachment to a dental implant, wherein the tool comprises a coupling section intended for coupling it to a drill bit, and a working area defined by a stem supporting at one end thereof a head having a plurality of cutting blades radially distributed with respect to a longitudinal axis of the coupling portion, wherein each cutting blade presents a lower cutting face. The lower cutting face presents a region with a convex curvature having a radius varying between a maximum and a minimumThe maximum value of the radius is equal to 0.1350 × Dh, wherein Dh corresponds to the diameter of the active area of the milling tool and the minimum value of the radius satisfies the following formula:)

1. A milling tool for mounting a screw in a dental structure, the screw being provided for bonding to a dental implant, wherein the tool comprises a coupling section provided for coupling to a milling machine and a working section defined by a stem supporting on one end a head having a plurality of cutting inserts distributed radially with respect to a longitudinal axis of the coupling section, wherein each cutting insert has a lower cutting face, characterized in that the lower cutting face has an area with a convex curvature having a radius varying between a maximum value and a minimum value,

the maximum value of the radius is equal to 0.1350 Dh, where Dh corresponds to the diameter of the active area of the milling tool and the minimum value of the radius conforms to the following formula:

2. the milling tool of claim 1, wherein the minimum radius is less than 0.1350 x Dh.

3. The milling tool of claim 1 wherein the working section comprises between two and six cutting inserts.

Background

The goal of dental implant systems is to reestablish normal functions for patients of comfort, appearance, speech and health, regardless of the oral conditions they may have. These implant systems are based on placement by means of dental implants inserted into the mandible of the patient. Dental prostheses can be fixed to these implants by means of screws which pass through the prosthesis by means of channels for inserting screw elements.

When the channel for inserting the screw element does not have a straight trajectory (meaning that the longitudinal axis of the channel is not straight for its entire path), a special milling tool is used to machine the screw seat inserted into the channel. In the state of the art, milling tools with a substantially T-shaped cross-section are known comprising a coupling section provided for coupling to a milling machine and a working section defined by a bar supporting on one end a plurality of cutting inserts radially distributed with respect to a longitudinal axis of the coupling section, wherein each cutting insert has a lower cutting face. In these types of T-shaped tools, the lower cutting face forms the screw seat, thereby making it necessary to measure each angle of the seat and screw using a different tool.

For proper working, the milling tool enters through the exit hole of the screw (in other words, the hole of the channel for the screw closest to the implant crown interface). Most implant manufacturers make the hole with a measurement equal to the size of the screw plus an additional safety space, which is usually at most 10% of the size value, and therefore for calculations the diameter of the active area of the tool is at most 1.05 times the size of the screw.

The fact of having a larger diameter of the active area (Dh) implies a greater risk of collision due to variables that are difficult to control, such as manufacturing tolerances of the milling tool, operating accuracy, vibrations of the milling tool during its operation or bending of the tool during its rotational movement, etc.

It is worth mentioning that for the calculation the diameter of the shank of the tool (Dt) (see fig. 1) will be the minimum 10% of the diameter of the active area of the milling tool (Dh). Smaller diameters would not be feasible because, on the one hand, a significant degree of bending occurs during rotation of the milling tool, and, on the other hand, less than 10% of the Dh of the shank would be too brittle to withstand the stresses and bending and torque momentum generated during use of the tool.

Screws commonly used for dental implants are comprised between dimensions of 1.4mm and 2.5mm, and these screws are usually introduced into channels which usually do not have a desired straight trajectory, wherein the maximum ratio is 0.60, as can be seen in the table below, wherein for the different values of dimensions commonly used the following maximum ratio M/Dc is obtained (Dc is the diameter of the screw head):

size of	Maximum ratio M/Dc
		M1.4	0.60
M1.6	0.67
		M1.8	0.71
M2	0.75
		M2.5	0.74

Furthermore, the contact surface between the screw and the base cannot be machined without roughness. During loading, this roughness on the contact surfaces can be smoothed, causing a loss of preload of between 2% and 10% of the screw with conventional machining conditions, which loss of preload is directly related to the roughness of the screw seat. Therefore, within the manufacturing limits, the surface roughness must be as minimal as possible.

Below which the minimum radius of the milling tool is below, the milling tool is no longer effective, due to the fact that too small a radius will render the surface roughness of the screw seat being milled unsuitable, with the result that the screw becomes loose, even though the surface roughness may be changed by changing the cutting conditions. However, modifying the cutting conditions may lead to a series of disadvantages, such as lengthy milling times, etc., thereby increasing costs, and on the other hand, cutting conditions for a tool that are far from ideal may cause premature wear of the tool.

Moreover, the applicant is not presently aware of inventions having all the features described in this specification.

Disclosure of Invention

It is an object of the present invention to improve the invention to provide a tool that is configured to be novel in the field of application and that solves the previously mentioned drawbacks, and that also contributes to other additional advantages that will be evident from the following description.

It is therefore an object of the present invention to provide a milling tool for mounting a screw in a dental structure, the screw being provided for bonding to a dental implant, wherein the tool comprises a coupling section provided for coupling to a milling machine and a working section defined by a shank, the shank supporting on one end a head having a plurality of cutting inserts radially distributed with respect to a longitudinal axis of the coupling section, wherein each cutting insert has a lower cutting face.

In particular, the invention is characterized by the fact that: the lower cutting face has a region with a convex curvature, the convex curvature having a radius that varies between a maximum value and a minimum value,

the maximum value of the radius is equal to 0.1350 × Dh, where Dh corresponds to the diameter of the milling tool active area and the minimum value of the radius follows the formula:

it is worth mentioning that the diameter of the active area of the milling tool will correspond to the diameter defined by the cutting insert in plan view, as indicated in fig. 1.

It must be considered that Df (diameter of the screw channel) is at least equal to Dc plus twice the radius of the lower cutting face, and therefore Df:

Df＝M-Dt+Dh

thanks to these features, a working tool is achieved that is envisaged to be viable in a large number of cases, due to the fact that it allows different seat angles (with different seat angles) to be machined, without the need to use different milling tools for each screw with different seats and/or sizes. Generally, the screw is associated with the type or size of the dental implant.

The minimum radius of the lower cutting zone allows to obtain an acceptable manufacturing roughness, on the other hand, the definition of the maximum radius is determined by the fact that: above established values, and considering the commercial dimensions of the screws used for the implant, it will not be possible to mill seats large enough to enable the screws to be properly seated.

The minimum radius is less than 0.1350 × Dh.

For the minimum radius, it has been considered that for milling machines of this scale, the standard values for radial and axial depths of cut for milling of cobalt and titanium alloys are typically 5% to 10% of the diameter of the milling tool, and the minimum acceptable values are about 0.12% of the diameter (Dh) of the active area of the tool.

It is also preferred that the working section of the milling tool of the present invention comprises between two and six cutting inserts.

The milling tool described thus represents an innovative structure having, for its intended purpose, structural and compositional features heretofore unknown, for the reason that together with its utility, provide the milling tool with sufficient basis for obtaining the requested exclusive privilege.

Other characteristics and advantages of the milling tool object of the present invention will become clear from the description of a preferred but not exclusive embodiment, illustrated by way of non-limiting example in the accompanying drawings, wherein:

drawings

Fig. 1 is a schematic front view of an arrangement of a milling tool according to the invention in a channel of an arrangement of screw elements for a dental implant;

fig. 2 is a schematic front view of an arrangement of a milling tool according to the invention in a channel of an arrangement of screw elements for a dental implant, wherein the channel has a frusto-conical intermediate cross-section;

FIG. 3 is a front and plan view of a tool according to the present invention;

FIG. 4 is an enlarged front view of a working section of the milling tool;

fig. 5 is a front view of a screw for a dental implant; and

fig. 6 is a schematic front view of the arrangement of the screw within the channel.

Detailed Description

In view of the above-described drawings and in accordance with the numbering adopted, there may be observed therein examples of preferred embodiments of the present invention including the components and elements thereof as hereinafter particularly indicated and described.

As can be seen, an embodiment of a milling tool, generally indicated with reference numeral (1), is provided for mounting a screw (3) in a dental structure, the screw (3) having a size comprised between 1.4mm and 2.5 mm. In particular, the tool (1) mainly comprises a coupling section (10) and a working section (20), the coupling section (10) being arranged for coupling to a milling machine, the working section (20) being defined by a stem (201), the stem (201) supporting on one end a head having a plurality of cutting inserts (202), the plurality of cutting inserts (202) being radially distributed with respect to a longitudinal axis of the coupling region end, wherein each cutting insert (202) has an upper cutting face (a), a lateral cutting face (B) and a lower cutting face (C), as shown in fig. 1, 2 and 4.

In the illustrated embodiment, the working section (20) includes four radially distributed cutting inserts (202), as seen in fig. 3.

With reference to the lower cutting face (C), in the profile view, the lower cutting face (C) has a section with a convex curvature having a radius (R) varying between a maximum value and a minimum value, the maximum value of the radius being equal to 0.1350 × Dh, wherein Dh corresponds to the diameter of the active area of the milling tool.

On the other hand, the minimum value of the radius (also called minimum radius) in millimeters must comply with the following formula:

based on the above description, the table is provided with the ratio between the diameter of the active area of the milling tool comprised between 1.4mm and 2.5mm and the maximum and minimum radius allowable by the milling machine described herein:

Dh(mm)	Rmaximum of(mm)	RMinimum size(mm)
			1.4	0.189	0.093
1.6	0.216	0.106
			1.8	0.243	0.119
2	0.270	0.133
			2.5	0.338	0.166

The details, shape, dimensions and other complementary elements used for manufacturing the tool of the invention may be substituted appropriately otherwise, without thereby departing from the scope defined by the following claims.

Reference numerals

Dc diameter of screw head

Df diameter of screw channel

Dt diameter of milling machine rod

Dh diameter of effective area of milling machine

1 milling tool

10 coupling segment

20 working section

201 rod

202 cutting insert

Radius of the lower cutting plane

Size M

2 channel

3 screw

A cut surface

B side cutting face

Sliced noodles under C