CN114145867B

CN114145867B - Preparation method of dental preparation guide plate beneficial to removable partial denture abutment stabilization

Info

Publication number: CN114145867B
Application number: CN202111478867.4A
Authority: CN
Inventors: 吴�琳; 刘小舟; 肖继伟
Original assignee: HOSPITAL OF STOMATOLOGY CHINA MEDICAL UNIVERSITY
Current assignee: HOSPITAL OF STOMATOLOGY CHINA MEDICAL UNIVERSITY
Priority date: 2021-12-06
Filing date: 2021-12-06
Publication date: 2024-03-01
Anticipated expiration: 2041-12-06
Also published as: CN114145867A

Abstract

The invention discloses a preparation method of a tooth preparation guide plate beneficial to the stability of removable partial denture abutments, which comprises the following steps: introducing a dental model M of dentition defect into CAD software, and determining an occlusion plane P of the dental model M to be processed; importing a plane M (P1) into software, and establishing a straight line on the plane M (P1) for measuring the countermeasure distance; then respectively importing second to seventh plane models [ M (P2), M (P3), M (P4), M (P5), M (P6) and M (P7) ], and combining the six planes into a hexahedral model M (hex); performing Boolean subtraction operation on the M (hex) and the dental model M to obtain a dental preparation guide plate model M (g_p); 3D printing the tooth preparation guide plate model M (g_p) by using a resin material to obtain a tooth preparation guide plate; the tooth preparation guide plate is convenient for making corresponding accurate tooth preparation on the axial surface of the side of the abutment to be placed against the arm.

Description

Preparation method of dental preparation guide plate beneficial to removable partial denture abutment stabilization

Technical Field

The invention belongs to the field of stomatology, and particularly relates to a preparation method of a dental preparation guide plate which is beneficial to the stability of removable partial denture abutments.

Background

Removable partial dentures (Removable Partial Denture, RPD) are prostheses that are self-removable by the patient, using natural teeth, submucosa and bone tissue as support, relying on the retainers and base of the dentures to retain, restoring the morphology and function of the missing teeth with artificial teeth, restoring the morphology of the defective alveolar ridge, jawbone and surrounding soft tissue with base material. At present, removable partial dentures are still the most common repair method for patients with dentition defects in China.

The removable partial denture consists of a retainer, a bracket, an artificial tooth, a connector and a base. Wherein the retainer can serve to retain, stabilize and support the removable partial denture. The retainers are divided into direct retainers and indirect retainers according to different actions, and the direct retainers of the removable partial denture are mainly snap rings which are clamped on the abutment teeth to play a main role in retaining.

In the process that the elastic clasp retention arm of the denture enters and exits the undercut region along the external shape of the abutment tooth according to the direction of the denture placement channel under the action of external force, if the countermeasure arm does not play a role correspondingly, horizontal lateral force can be generated on the abutment tooth, thereby causing the abutment tooth Zhou Sunshang and the loosening of the tooth, and being difficult to cure clinically.

How to balance the counter arm against the retention arm by precisely abrading the corresponding dental tissue according to the denture positioning channel direction is a necessary condition for stabilizing the abutment. However, existing clinical procedures often rely on the experience of the operator, lacking in objective means and guidance.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a preparation method of a dental preparation guide plate, which utilizes the prior CAD (Computer Aided Design) and CAE (Computer Aided Engineering) technologies to determine a positioning channel (namely the denture wearing direction) by using a digital model, measures the distance of generating lateral force on an abutment by a denture according to the distance of a retention arm entering an abutment undercut region, designs a counter arm side guide plane guide plate, and designs an adjacent surface guide plane guide plate on the near-gap side of the abutment.

In order to achieve the above purpose, the invention adopts the following technical scheme: (1) Introducing a dental model M of dentition defect into CAD software, and determining an occlusion plane P of the dental model M to be processed;

(2) From the direction of the seat, i.e. the normal direction of the occlusal plane, a plane M (P1) perpendicular to the occlusal plane P can be determined and introduced into the model;

(3) On the abutment, a clasp arm tip start position point on the side of the retention arm (typically the buccal side of the tooth) is determined, and the plane M (P1) is moved in parallel so as to pass through the clasp arm tip start position point and intersect with the abutment model to be processed in the dental model M;

(4) The observation direction is observed from the direction perpendicular to the occlusal plane, and the outline high point pt1 of the retention arm side of the abutment on the plane M (P1) is found;

(5) Establishing a straight line l passing through the point pt1 and oriented perpendicularly to the occlusal plane P, since the plane M (P1) is perpendicular to the occlusal plane P, it being evident that this straight line l lies within the plane M (P1);

(6) In the plane M (P1), moving a straight line I in parallel towards the inner direction of the abutment, wherein the moving distance is 0.25mm or 0.5mm or 0.75mm, the moving distance is determined according to different clasp materials and different depths of the clasp materials entering into the undercut region of the abutment, so that the moved straight line I has two intersection points with the abutment in the plane M (P1), and the distance d between the two intersection points is determined through measurement;

(7) A second plane M (P2) is led in, so that the plane M (P2) is on the side of the countermeasure arm and is perpendicular to the occlusion plane P, and intersects with the axial plane of the abutment countermeasure arm to be processed in the dental model M, the position of the plane M (P2) is adjusted in parallel, and the distance between the upper extreme point and the lower extreme point in the direction perpendicular to the occlusion plane is d in the shape formed by intersecting the plane M with the abutment;

(8) A third plane M (P3) is led in, so that the plane M (P3) is on the gap side and vertical to the occlusal plane P, and intersects with the gap side axis of the abutment in the model M, the position of M (P3) is adjusted in parallel, and the distance between the upper extreme point and the lower extreme point in the direction vertical to the occlusal plane is 2-3mm in the shape formed by intersecting with the abutment;

(9) Introducing a fourth plane model M (P4) and a fifth plane model M (P5), wherein the M (P4) is positioned on the side of the abutment retention arm, the M (P5) is positioned on the side of the abutment far gap, and the M (P4) and the M (P5) do not intersect with the abutment model; the proximal and distal parts of the abutment are the gap sides, and the M (P5) plane is led into and the step (8) is repeated, so that M (P2), M (P3), M (P4) and M (P5) form four planes surrounding the abutment;

(10) A sixth plane model M (P6) and a seventh plane model M (P7) are led in, and the two planes M (P6) and M (P7) are respectively parallel to the occlusal plane P and are respectively used as the upper surface and the lower surface of the tooth preparation guide plate; the upper surface of the tooth preparation guide plate is Yu Jiya-4 mm, the opening degree of the rear teeth can be properly reduced if the opening degree is small, the minimum opening degree is not less than 2mm, the lower surface is Yu Jiya gingiva, but the opening degree is not higher than the lower extreme points of the shapes formed by intersecting M (P2) and M (P3) with the abutment teeth;

(11) Combining six planes of M (P2), M (P3), M (P4), M (P5), M (P6) and M (P7) into a hexahedral model M (hex);

(12) Performing Boolean subtraction operation on the M (hex) and the dental model M to obtain a dental preparation guide plate model M (g_p);

(13) 3D printing the tooth preparation guide plate model M (g_p) by using a resin material to obtain a tooth preparation guide plate; and the four printed planes M (P4), M (P5), M (P6) and M (P7) are properly trimmed, so that the printed planes M (P4), M (P5), M (P6) and M (P7) are easy to be mounted on the abutment to be processed.

The tooth preparation guide plate obtained by the invention is a hexahedron with a certain shape at the plane M (P2) and the plane M (P3) and an abutment shape inside. The planes M (P2) and M (P3) correspond to the counterarm side (generally lingual palate side) and the near-lacunar side of the abutment, respectively. When the tooth body preparation guide plate is sleeved on the abutment, a part of the tooth body preparation guide plate is exposed out of the counter arm side and the near-gap side of the abutment, the two parts are respectively ground to be flush with the planes M (P2) and M (P3), the obtained two parts of planes are the guide planes of the abutment, the guide planes of the counter arm side can be used for placing the counter arm, the side force generated by the abutment when the retaining arm is in place is antagonized, and the guide planes of the near-gap side can be used for placing the adjacent panel to play roles of auxiliary retention and partial balance antagonism.

Compared with the prior art, the invention has the beneficial effects that: the tooth preparation guide plate is convenient for making corresponding accurate tooth preparation on the side of the counter arm of the tooth, and the counter arm side guide plane of the counter arm of the tooth prepared by the tooth preparation guide plate can ensure that the counter arm of the clamping ring can accurately form counter with the retention arm, so that a patient is ensured not to damage the healthy abutment teeth in the process of taking off and wearing the denture, and no side force is generated, and meanwhile, the clamping ring has an elastic clamping effect and prevents the denture teeth from being closed and dislocated.

Drawings

Fig. 1 is a view of a dental model M in the present embodiment;

FIG. 2 is a schematic diagram of step (2) in the present embodiment;

FIG. 3 is a schematic view showing the structure of a removable partial denture clasp according to the present embodiment;

FIG. 4 is a schematic view showing the intersection of the plane M (P1) and the abutment in the present embodiment;

FIG. 5 is a schematic diagram showing the steps (4), (5) and (6) in the present embodiment;

FIG. 6 is a schematic view of a plane M (P2) in the present embodiment;

fig. 7 is a schematic view of a plane M (P3) in the present embodiment;

FIG. 8 is a schematic diagram of planes M (P4) and M (P5) in the embodiment;

FIG. 9 is a schematic diagram of planes M (P6) and M (P7) in the embodiment;

fig. 10 is a schematic diagram of a hexahedral model M (hex) formed by combining six planes M (P2), M (P3), M (P4), M (P5), M (P6), and M (P7) in the present embodiment;

FIG. 11 is a schematic view of a dental preparation guide plate model in the present embodiment;

fig. 12 is a schematic view of the dental preparation guide plate prepared in this embodiment in place on an abutment.

Wherein: 1-clasp arm tip, 2-clasp arm body, 3-clasp arm shoulder, 4-countermeasure arm, 5-plane M (P1), 6-plane M (P2), 7-plane M (P3), 8-plane M (P4), 9-plane M (P5), 10-plane M (P6), 11-plane M (P7), 12-countermeasure arm side guide plane, 13-near-gap side guide plane.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The embodiment provides a technical scheme: the guide plate fabrication scheme was implemented using geomic software.

(1) Importing a dental model M which is required to be designed and prepared into a removable partial denture by using Geomagic software, and determining a dental model occlusion plane P; the dental model M is shown in fig. 1.

(2) From the direction of the seat, i.e. the normal direction of the occlusal plane P, a plane M (P1) perpendicular to the occlusal plane P can be determined and introduced into the model. As shown in fig. 2.

(3) On the abutment to be treated, a clasp arm tip start position point on the retention arm side (the buccal side of the tooth in this embodiment) is determined. The removable partial denture clasp is structured as shown in fig. 3, and comprises: a clasp arm tip 1, a clasp body 2, a clasp arm shoulder 3 and a counter arm 4. The plane M (P1) is translated so as to pass through the clasp arm tip start point and intersect the abutment model to be treated in the dental model M.

(4) The coordinates of the profile high point pt1 on the plane M (P1) on the retention arm side of the abutment are found by observation from the direction perpendicular to the occlusal plane (observation direction).

(5) A straight line l is established through the point pt1 and directed perpendicular to the occlusal plane P, since the plane M (P1) is perpendicular to the occlusal plane P, it being apparent that this straight line l lies within the plane M (P1).

(6) In the plane M (P1), a straight line l is moved in parallel in the direction of the inside of the abutment by a distance of 0.25mm or 0.5mm or 0.75mm, and the moved straight line l has two intersection points a and b with the abutment in the plane M (P1), and the distance d between the intersection points is determined by measurement, wherein d is 2.06mm in the embodiment. Let a be the position where the arm initially hits the tooth, and b be the lowest position where the arm tip enters the undercut region.

The schematic process of steps (4), (5) and (6) is shown in fig. 5, and fig. 5 shows that in the plane M (P1), the vertical direction is the observation direction perpendicular to the occlusal plane, and is also the direction of the straight line l. The curve in the figure is the intersection of the contour of the tooth on the side of the abutment retention arm with the plane M (P1).

(7) The second plane M (P2) is introduced so that the plane M (P2) is perpendicular to the occlusal plane P on the side of the abutment arm (generally, lingual/palatal surface) and intersects the axial plane (generally, lingual/palatal surface) of the abutment arm to be processed in the dental model M, and the position of M (P2) is adjusted in parallel so as to intersect the abutment, so that the distance between the upper and lower extreme points in the direction perpendicular to the occlusal plane is d=2.06 mm. From the composition of removable partial dentures, the component part which plays a direct retention role is the clasp, and when the clasp plays a role, the clasp mainly relies on the clasp arm tip to enter the undercut region, and if antagonism of the antagonistic arm is not generated in the process, the action of force on the clasp arm tip from contacting the abutment is generated. As shown in fig. 6, the plane in fig. 6 is the last determined plane M (P2).

(8) The third plane M (P3) was introduced so that the plane M (P3) was perpendicular to the occlusion plane P on the clearance side and intersected with the abutment clearance side axis (in this embodiment, the mesial plane) in the model M, and the position of M (P3) was adjusted in parallel so as to intersect with the abutment, so that the distance between the upper and lower extreme points in the perpendicular occlusion plane direction was 3.03mm. As shown in fig. 7.

(9) The fourth and fifth planar models M (P4) and M (P5) are introduced, M (P4) is located on the abutment retention arm side (labial side in this example), M (P5) is located on the abutment distal gap side, and M (P4) and M (P5) do not intersect the abutment model. In another case, the proximal and distal portions of the abutment are both on the side of the gap, and the M (P5) plane introduction process is repeated in step (8). Up to this point M (P2), M (P3), M (P4), M (P5) constitute four planes around the abutment, as shown in fig. 8.

(10) A sixth plane model M (P6) and a seventh plane model M (P7) are led in, and the two planes M (P6) and M (P7) are respectively parallel to the occlusal plane P and are respectively used as the upper surface and the lower surface of the tooth preparation guide plate; the upper surface of the tooth preparation guide plate is about 3-4mm higher than the abutment, the opening degree of the rear tooth can be properly reduced if the opening degree is small, the minimum is not less than 2mm, and the lower surface can be higher than the abutment gingiva but not higher than the lower extreme point of the shape formed by intersecting M (P2) and M (P3) with the abutment. As shown in fig. 9.

(11) Six planes of M (P2), M (P3), M (P4), M (P5), M (P6) and M (P7) are combined into a hexahedral model M (hex). As shown in fig. 10.

(12) And (3) carrying out Boolean subtraction operation on the M (hex) and the dental model M to obtain a dental preparation guide plate model M (g_p). As shown in fig. 11.

(13) The dental preparation guide model M (g_p) is 3D printed with a resin material, and a dental preparation guide is obtained. The four printed planes M (P4), M (P5), M (P6) and M (P7) can be properly trimmed to facilitate fitting on the abutment to be treated.

The dental preparation guide plate obtained by the implementation is a hexahedron with a certain shape at the plane M (P2) and the plane M (P3) and an abutment shape inside. The planes M (P2) and M (P3) correspond to the countermeasure arm side (palate side in this embodiment) and the near-gap side (mesial side in this embodiment) of the abutment, respectively. As shown in fig. 12, when the tooth preparation guide plate is nested on the abutment, a part of tooth tissue is exposed out of the tooth preparation guide plate on the opposite arm side and the near-gap side of the abutment, the two parts are respectively ground to be flush with the planes M (P2) and M (P3), the obtained two part planes are the guide planes of the abutment, the guide planes on the opposite arm side can be used for placing the opposite arm, the lateral force generated on the abutment when the retaining arm is in place is antagonized, and the guide planes on the near-gap side can be used for placing the adjacent panel to play roles of auxiliary retention and partial balance antagonism.

The foregoing description is only of the preferred embodiments of the present application and is not intended to limit the same, but rather, various modifications and variations can be made by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application. It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition and explanation thereof is necessary in the following figures.

The foregoing is merely specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the present application, and the changes and substitutions are intended to be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. The preparation method of the dental preparation guide plate for facilitating the stability of removable partial denture abutment is characterized by comprising the following steps:

(1) Introducing a dental model M of dentition defect into CAD software, and determining an occlusion plane P of the dental model M to be processed;

(3) Determining a clasp arm tip initial position point on the side of a retention arm on an abutment, and moving a plane M (P1) in parallel so that the plane M passes through the clasp arm tip initial position point and intersects an abutment model to be processed in a dental model M;

(7) A second plane M (P2) is led in, so that the plane M (P2) is on one side of the countermeasure arm and is perpendicular to the occlusion plane P, and intersects with the axial plane of the abutment countermeasure arm to be processed in the dental model M, the position of the plane M (P2) is adjusted in parallel, and the distance between the upper extreme point and the lower extreme point in the direction perpendicular to the occlusion plane is d in the shape formed by intersecting the plane M with the abutment;