RU2823468C1 - Cad/cam method for making individual impression tray for full dentures - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, particularly to orthopaedic dentistry and is intended for use in orthopaedic treatment of patients with complete adentia. At the stage of patient’s examination, a degree of Suppli’s mucous membrane compliance, presence of exostoses, movable ridges, features of a relief of the mucous membrane are detected. In the process of digital scanning of edentulous jaws with the help of software tools, places of maximum and minimum compliance, exostoses, movable ridges are marked on the obtained image with a digital colour marker. At the end of scanning, final evaluation of the obtained image is carried out, the scans are saved in the appropriate format and sent to the dental laboratory. In a dental laboratory, an individual tray and supports are modeled to exclude pressure on undesirable areas of the mucous membrane, to exclude compression on them and to create an optimal gap for uniform distribution of the impression material on the prosthetic bed. At the same time, in case of I class by Suppli, 4 supports are installed: 2 on the right and on the left in the area of the second molars, 2 on the right and on the left in the area of the canines, regardless of the upper or lower jaw with the height of supports of 2 mm, width and length of 7–8 mm by 7–8 mm; in case of II class by Suppli, 3 supports are installed: 1 on right and 1 on the left in the area of the first molars, 1 between the central incisors, with a height of supports of 1 mm, a width and length of 8–9 mm by 8–9 mm; in case of III and IV class by Suppli, 3 supports are installed in the areas of the least pliable and movable mucosa, so that there is no balance of the impression tray when it is applied on the jaw with the height of supports of 3 mm, width and length of 10-11 mm by 10–11 mm, with 3-4 perforations of a tray, with diameter of 1 mm, for removal of excess impression material in a projection of movable ridges. Further, in all cases with the shape of the supports adjacent to the mucous membrane corresponding to its relief in the contact zone, 3D printing, processing and fitting in the oral cavity are performed; functional design of borders with silicone or thermoplastic material and taking a final impression.

EFFECT: method, by taking into account the individual characteristics of the edentulous jaw of the patient and the use of digital technologies, enables to individually create the required space between the surface of the tray and the prosthetic bed without excessive compression on the underlying tissues, for the best distribution of the impression material, taking into account the type of mucosa and the required impression.

1 cl, 2 dwg, 2 ex

Description

The invention relates to medicine, in particular to orthopedic dentistry, and is aimed at improving the quality of orthopedic treatment of patients with complete edentia.

Currently, one of the most pressing issues in the manufacture and use of complete removable dentures is increasing the reliability of fixation of the prosthesis on the prosthetic bed of the upper or lower jaw.

The degree of fixation of the prosthesis depends on the anatomical conditions of the oral cavity, the type of mucous membrane, bone protrusions, the method of obtaining an impression and the manufacture of an individual dental tray.

To ensure the adhesion of a dental prosthesis, it is necessary that its surface accurately reflects the corresponding tissues of the prosthetic bed and that there is no deformation of the underlying tissues through the pressure of the impression material during the process of taking an impression with an individual tray.

The well-known “Tray for taking an impression when repairing partial removable laminar dentures” (RU 110259 U1). The design of the tray for taking an impression consists of a spoon handle, a perforated base and the sides of the tray, which additionally have stops located on its base, the length of which corresponds to the width of the base of a standard tray, their height is 3-4 mm, and their width is 2-4 mm. The stops are made of base wax or self-hardening plastic Patern resin LS or Tempron.

The disadvantage of this method is the location of the stops, regardless of the anatomical features of the relief of the toothless jaw.

The known “Method for the manufacture of functional and aesthetic removable dentures” (EA045576B1). When using it, to prevent squeezing or compression with an individual tray, the doctor places 4-6 stop stops on it, and they are placed in the place of dense bone, takes an impression of the prosthetic bed of the upper jaw with a non-hydrophilic and non-thixotropic corrective mass A-silicone or polyester mass, while performing functional tests.

The disadvantage of this method is the lack of differentiation of the number of stops, their shape and size from the characteristics of the compliance of the mucosa and the non-use of CAD/CAM technologies.

The objective of the invention is to eliminate these disadvantages by taking into account the individual characteristics of the patient's toothless jaw and using digital technologies in the manufacture of individual trays with stops.

The CAD/CAM method for manufacturing a customized impression tray for complete dentures is as follows.

At the stage of examining a patient with complete edentia, examination and palpation of the oral cavity, the doctor identifies the degree of pliability of the mucous membrane according to Supple, the presence of exostoses, mobile ridges, and features of the relief of the mucous membrane.

In the process of digital scanning of edentulous jaws using software tools (digital color marker), the resulting image marks the places of greatest and least compliance, exostoses, and movable ridges. At the end of the scan, a final assessment of the resulting image is carried out, the scans are saved in the appropriate format and sent to the dental laboratory.

In the dental laboratory, the operator virtually models an individual tray and stops to eliminate pressure on undesirable areas of the mucous membrane, eliminate compression on them and create an optimal gap for uniform distribution of the impression material over the prosthetic bed.

The number of stops, their height, width, length and shape of the part adjacent to the mucous membrane vary, depending on the individual anatomical characteristics of the patient with complete edentia.

In particular, with well-defined alveolar processes covered with a slightly pliable mucous membrane without pathological processes (Class I according to Suppli), 4 stops are installed evenly distributed along the alveolar ridge (2 on the right and left in the area of the second molars, 2 on the right and left in the area of the canines), regardless of the upper or lower jaw. In this case, the height of the stops (that is, the space for the corrective layer of impression material) is 2 mm, the width and length of the stops are 7-8 mm by 7-8 mm (Fig. 1).

The shape of the stop adjacent to the mucous membrane corresponds to its relief in the contact zone and repeats it (Fig. 2).

In the presence of dense, stubborn, atrophied, dry mucosa, painful areas of the mucosa on palpation, exostoses (II class according to Suppli), 3 stops are installed evenly distributed along the alveolar ridge (2 on the right and left in the area of the first molars, 1 between the central incisors, regardless of upper or lower jaw. In this case, the height of the stops (that is, the space for the corrective layer of impression material) is 1 mm, the width and length of the stops are 8-9 mm by 8-9 mm. The shape of the stops adjacent to the mucous membrane corresponds to its relief in the contact zone. and repeats it.

In the presence of hypertrophied, loose mucosa, a mobile ridge and easily dislodged cords (III and IV class according to Supplee), 3 stops are installed in the areas of the least pliable and mobile mucosa, so that there is no balance of the impression tray when it is applied to the jaw. To do this, it is necessary to ensure a relatively uniform distribution of stops along the entire arch of the alveolar processes. In this case, the height of the stops (that is, the space for the corrective layer of impression material) is 3 mm, the width and length of the stops are 10-11 mm by 10-11 mm. The shape of the support adjacent to the mucous membrane corresponds to its relief in the contact zone and repeats it. In the projection of the movable ridges, 3-4 perforations of the tray, 1 mm in diameter, are programmed to remove excess impression material.

After computer modeling of an individual tray with stops, it is manufactured using 3D printing, processed, fitted in the oral cavity, functionally decorated with silicone or thermoplastic material, and the final impression is taken.

The specified CAD/CAM method for manufacturing an impression tray for complete removable dentures allows, without excessive compression on the underlying tissues, to individually create the necessary space between the surface of the tray and the prosthetic bed, for the best distribution of the impression material, taking into account the type of mucosa and the required impression (compression, unloading).

Clinical example No. 1

Patient K., 68 years old, applied to the orthopedic dentistry clinic for the manufacture of a complete removable denture of the upper jaw. During the examination, type I compliance was determined according to Supple, the alveolar processes are pronounced, the mucous membrane is pale pink, dense. When scanning jaws digitally, 4 stops are installed evenly distributed along the alveolar ridge (2 on the right and left in the area of the second molars, 2 on the right and left in the area of the canines). The height of the stops is 2mm, the width and length of the stops are 8mm by 8mm. An individual tray was made using 3D printing, fitted in the oral cavity using functional tests and material for decorating the borders of Kerr dentures. Final impressions are taken and the complete denture is fabricated according to manufacturing standards. During dynamic observation, good fixation of the prosthesis and the absence of complaints were determined. Examination of the oral cavity revealed no areas of inflammation or excessive compression.

Clinical example No. 2

Patient L., 72 years old, complained of a breakage of a complete removable denture of the lower jaw. It is recommended to make a new prosthesis. During the clinical examination, a mobile ridge was revealed in the frontal area of the lower jaw. The mucous membrane is highly pliable, loose, type IV according to Supple. This area is marked with a digital marker during scanning of the edentulous lower jaw. During digital modeling, 3 stops are planned in the areas of the least pliable and mobile mucosa, so that there is no balance of the impression tray when it is applied to the jaw. The height of the stops is 3mm, the width and length of the stops are 11mm by 11mm. In the projection of the movable ridge of the lower jaw, 4 tray holes, 1 mm in diameter, were made to remove excess impression material. An individual tray was made using 3D printing and fitted into the oral cavity using functional tests and material for decorating the borders of Bisiko dentures. Final impressions were taken and a complete removable denture was fabricated in accordance with the digital protocol. Long-term observation showed no complaints about the fixation of the lower jaw prosthesis, the mucous membrane was pale pink, the movable ridge was not pinched, the patient was satisfied with the manufactured prosthesis.

Description of images

Fig. 1 - Schematic illustration of an individual spoon with stops for the mucous membrane.

1. The sides of an individual spoon.

2. The support for the mucous membrane in the upper part corresponds in shape to the alveolar process.

3. Individual spoon handle.

Fig. 2 - Schematic representation of the relationship between the upper surface of the stop (its shape) and the relief of the mucous membrane of the alveolar process.

1. The side of an individual spoon.

2. The support for the mucous membrane in the upper part corresponds in shape to the alveolar process.

4. Alveolar process of the maxilla in the lateral region.

Claims (5)

A CAD/CAM method for manufacturing an individual impression tray for complete removable dentures, including examination of a patient with complete edentia, examination and palpation of the oral cavity by a doctor, characterized in that the degree of compliance of the mucous membrane according to Supple is revealed, the presence of exostoses, moving ridges, and features of the relief of the mucous membrane; carry out a digital scan of toothless jaws with a digital color marker marking the places of greatest and least compliance, exostoses, moving ridges; carry out modeling where: in class I according to Suppli, 4 stops are installed: 2 on the right and left in the area of the second molars, 2 on the right and left in the area of the canines, regardless of the upper or lower jaw with a stop height of 2 mm, width and length of 7-8 mm by 7-8 mm ; in class II according to Suppli, 3 stops are installed: 1 on the right and 1 on the left in the area of the first molars, 1 between the central incisors, with a stop height of 1 mm, width and length of 8-9 mm by 8-9 mm; in classes III and IV according to Suppli, 3 stops are installed in the areas of the least pliable and mobile mucosa, so that there is no balance of the impression tray when it is applied to the jaw with a stop height of 3 mm, width and length of 10-11 mm by 10-11 mm, with 3-4 perforated trays, 1 mm in diameter, to remove excess impression material in the projection of the movable ridges; further, in all cases, with the shape of the stops adjacent to the mucous membrane corresponding to its relief in the contact zone, 3D printing, processing and fitting in the oral cavity are performed; functional border design with silicone or thermoplastic material and taking the final impression.