RU2572185C2 - Lingual individual orthodontic appliance and method for orthodontic treatment taking into account temporomandibular joint parameters - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: group of inventions refers to medicine, namely dentistry, and aims at correcting dental abnormalities and deformities. Routine orthodontic procedures are performed. A teleradiography (TRG) is recorded. The following parameters are marked on the TRG image: SNA, SNB, ANB angles and occlusal plane inclination. Sagittal and transversal joint guidance parameters are described. Stone models are made. The models are scanned. Upper and lower jaw digitised models are matched in a virtual articulator; a digitised virtual set-up model is created. A functional occlusion is checked. A plane of a dental bracket slot on the virtual model is designed in parallel with the occlusal plane. Upper incisor inclination is set with respect to a horizontal and matched with the sagittal joint guidance compromised no more than 2.5 degrees thereby forming an individual lingual bracket. A vertical bridge is set 2-3 mm. Shape differences of an inner dental surface are compensated by a thickness of a dental bracket base so that a distance from the dental bracket slot to a vestibular surface of symmetrical teeth is equal. The individual dental brackets are used on a milling machine with the use of metal or plastic precision cast work-pieces. After the dental brackets are positioned on the digitised virtual model, movable trays are modelled and milled for each tooth separately. The dental brackets are fixed in the oral cavity with the use of orthodontic adhesive. That is followed by inserting arch wire into the dental bracket slots and ligaturing. The arch wires are changed in the process of treatment in accordance with a common procedure.

EFFECT: by taking into account a position of condyloid process head, a slope of articular tubercle, a position of articular disk when planning the orthodontic treatment, the inventions allow achieving the optimum functional occlusion of each specific patient.

2 cl, 1 tbl, 7 dwg, 2 ex

Description

The invention relates to medicine, namely to dentistry. Designed for use in orthodontics for the correction of dentofacial anomalies and deformities. It includes the technology of manufacturing a bracket system using computer design and an individual bracket system.

Known methods for the treatment of orthodontic abnormalities and deformities with the help of locks fixed on the teeth, and a wire arc, which is a source of strength for moving teeth. Braces can be fixed both from the external - vestibular surface of the tooth, and from the internal - lingual (F. Ya. Khoroshilkina. Orthodontics. M. 2006, p. 35-37). Most modern bracket systems relate to the “straight wire” technique, which involves the use of preformed factory-made arcs and the application of individualizing bends at the final stage of treatment. The sticking of braces of the vestibular systems, as a rule, is carried out using the technique of “direct bonding”, when the braces are positioned directly in the oral cavity according to the guidelines on the tooth surface. This technique, as well as the use of standard braces, provides for the application of individualizing bends. Drawing bends on a wire arc requires high manual skills of an orthodontist, increases the time spent in the chair. The quality of treatment using the bracket system created using such technology is difficult to guarantee.

A known method is when the braces are positioned in the mouth using a portable mouth guard, the so-called "indirect fixation". The position of the braces is previously determined on the model of the jaw, then transferred to the oral cavity.

For positioning lingual braces, the technique of indirect gluing is most preferred. Modern lingual systems have several disadvantages. Due to the fact that the relief of the lingual surface of the tooth is individual, it is required to change the parameters of the base of the bracket or its groove, as well as apply bends to the arc to achieve the desired tooth position. It is also necessary to make a set-up model predicting the results of treatment (G. Scuzzo, K. Takemoto. Invisible orthodontics. "Quintessence", 2006, 149-150, 91-92).

Known methods are when computer design is used for the manufacture of braces (Patent RU No. 2429795. The system for manufacturing individual orthodontic appliances and related processes). Models of the jaws are scanned, then the necessary element is selected from the virtual base, which is subsequently manufactured on an injection machine and processed by EDM or otherwise. The disadvantage of the method is that there is no information on the calculation methods and parameters of an individually manufactured virtual three-dimensional orthodontic apparatus.

A known method of choosing tactics for orthodontic treatment (US Pat. RU 2447838). Treatment planning is based on the assessment of signs of dentoalveolar anomalies, analysis of biometric parameters and teleradiographs (TRG). The disadvantages include the fact that the position of the teeth is considered in isolation from the characteristics of the temporomandibular joint.

It is known that the temporomandibular joint characteristics direct the movements of the lower jaw, the topographic characteristics of the dentition and the functional range of movements of the mandibular joint are normally interconnected (J. Okeson. Management of temporomandibular disorder and occlusion. Edition 6. Mosby Elsevier 2006. pp. 111-120 )

The technical result is the development of an orthodontic treatment method using a lingual individual orthodontic apparatus, in which the incisors are positioned taking into account the angle of the sagittal articular path, changing the slope of the lingual bracket groove depending on the axiography data. When modeling take into account the inclination of the occlusal plane relative to the true horizontal.

The technical result is achieved as follows. At the first stage, a clinical examination of the patient is performed. Routine procedures are performed for orthodontic patients: interrogation, examination, collection of medical history data, photo-recording, imprinting for diagnostic gypsum models, and tele-radiography (TRG) is performed. The following parameters are recorded on the TRG: the angle SNA, SNB, ANB, the angle of inclination of the occlusal plane (Profitt UR Modern Orthodontics; translated from English by M. Medpress-inform, 2008, p.146). The parameters of the sagittal and transverse articular pathways are recorded using an axiograph, for example Cadiacs Compact, Gamma Dental. Plaster models of the jaws are made. Models are scanned on a dental scanner, such as Ceramill Map 400, Amann Girrbach and digitized. On the obtained digitized models of the upper jaw (FIG. 1) and lower jaw (FIG. 2), a tortoanomaly of tooth 21 (1) and tooth groups 41, 42, 31, 32 (2) are visible. The digitized models of the upper and lower jaw (3) are combined in a virtual articulator, for example Artex, Amann Girrbach (FIG. 3). Using a scale of the sagittal articular pathway (4), an adjustable incisor stage (5) and an element imitating the temporomandibular joint (6), an digitized virtual set-up model is constructed in the articulator. The set-up model reflects the ideal position of the teeth after orthodontic treatment (FIG. 4, FIG. 5), the tortoanomaly of tooth 21 (7) and tooth groups 41, 42, 31, 32 (8) are adjusted. Set the angle of inclination of the anterior incisors relative to the reference plane so that the angle of the sagittal incisor path (11) is equal to the angle of the sagittal articular path (9). Functional occlusion is checked. The plane of the bracket groove (12) on the virtual model is modeled parallel to the occlusal plane (13) (FIG. 6). Thus, the inclination of the upper incisors is set relative to the horizontal and brought into line with the angle of the sagittal articular path with a deviation of not more than 2.5 degrees, forming an individual lingual bracket (14) (FIG. 7). The value of the vertical overlap is set equal to 2-3 mm. Differences in the shape of the internal surface of the teeth are compensated by the thickness of the base of the bracket, so that the distance from the groove of the bracket to the vestibular surface of the symmetrical teeth is the same. On a five-axis milling machine, for example Ceramill Motion 2, Amann Girrbach, brackets are made of metal, for example, Sintron, Amann Girrbach, or ash-free plastic as a blank for precision casting. Moreover, the parameters of the braces are calculated individually for each patient and each tooth, in contrast to standard braces made by the factory method. In our case, each bracket is made with minimal standing in the oral cavity from hypoallergenic material with an enlarged, if necessary, platform. After braces are positioned on a virtual model, portable mouth guards for each tooth are modeled and milled separately.

 Braces are fixed in the oral cavity for orthodontic glue. A wire arc is inserted into the grooves of the brackets and fixed with ligatures. The change of arcs during the treatment is carried out according to the traditional method. Orthodontic treatment is carried out based on data on the condition of the temporomandibular joint.

At the end of the period of active orthodontic therapy, retention measures are carried out, consisting in fixing wire retainers or applying removable orthodontic appliances. Verification of compliance of the achieved results with those planned at the beginning of treatment is carried out by superposition of the set-up model and the scanned control model after the active phase of orthodontic treatment.

Clinical examples.

Patient K., 17 years old. Complaints: on the unaesthetic appearance of the front upper teeth, periodically occurring clicks in both temporomandibular joints.

Diagnosis: Distal occlusion of dentition, Engle class II, subclass 2, retrusion of teeth 11, 21, tortoanomaly 22, 23, mesioposinia 13, 14, 15, 16, 17, 23, 24, 25, 26, 27, tortoanomaly 31, 32, 41, 42. TMJ Dysfunction Helkimo dysfunction index is 2. According to the TRG angle SNA = 83, SNB = 78, ANB = 5 degrees.

The treatment plan according to the standard method: extraction of teeth 14, 24, treatment with a braces, straight wire technique, mouthpiece mouth.

The aesthetic result of the treatment is satisfactory. The duration of the active phase of treatment is 16 months. According to the dynamic monitoring of the temporomandibular joint, the dysfunction index after 6 months is 0, 1 year is 1, and six months after the end of treatment is 2.

Patient M., 18 years old. Complaints: the position of the teeth of the upper jaw, the crowded position of the teeth of the lower jaw. Clicks in both temporomandibular joints. Diagnosis: Distal occlusion of the dentition, Engle class II, subclass 2, retroposition 11.21, tortoanomaly 22, 23, mesioposinia 13,14,15,16,17,23,24,25,26,27, tortoanomalies 31,32 41.42. TMJ dysfunction. Helkimo dysfunction index is 2. Lower jaw retroposition. TWG data: angle SNA = 83, SNB = 77, ANB = 6 degrees). The wish of the patient to carry out treatment on a lingual bracket system in connection with its invisibility to others.

The treatment plan for the proposed method: tooth extraction 14.24. Fixing individually made lingual braces. The parameters of the torques of lingual braces of the upper incisors are 60 degrees. The slope of the sagittal articular path is 30 degrees. Extension of the lower jaw 1 mm anteriorly.

The aesthetic result of the treatment completely satisfied the patient. The duration of treatment is 16 months. Full fanging has been achieved. According to the data of dynamic observation after 6 months, the Helkimo index is zero, after 12 months. - zero, 6 months after the end of active orthodontic therapy, zero.

Patient B., 16 years old. Complaints: violation of the position of the upper incisors, periodic clicks in both temporomandibular joints. Diagnosis: Mesial occlusion, Engle class III, reverse incisive occlusion, TMJ dysfunction, Helkimo 3 dysfunction index. TRG angle SNA = 81, SNB = 81, ANB = 0 degrees.

Treatment for 14 months. Individually made lingual braces. A vertical overlap of 2 mm was achieved, the Helkimo index after 6 months - 1, after 12 months - zero, 6 months after the end of the active phase of orthodontic therapy, zero.

A distinctive feature of this invention is the use of data on the position of the head of the condylar process of the lower jaw, the angle of the slope of the articular tubercle, the position of the articular disc for planning orthodontic treatment (see table). The system allows you to achieve the optimum functional occlusion of each individual patient.

Table.

Comparative characteristics of orthodontic lingual orthodontic appliances

Comparison parameter Known Solution Suggested apparatus Accounting for the angle of the sagittal articular path No Yes The positioning of the jaw in a therapeutic position No Yes Torc parameters in treatment with removal Standard bracket with step change Stepless change depending on the angle of the articular path

Claims (2)

1. Lingual individual orthodontic apparatus made of metal or plastic, characterized in that the bracket groove is parallel to the occlusal plane, the angle of inclination of the upper incisors relative to the horizontal corresponds to the angle of the sagittal articular path with a deviation of no more than 2.5 degrees; the vertical overlap is 2-3 mm, and the differences in the shape of the internal surface of the teeth are compensated by the thickness of the base of the bracket, so that the distance from the bracket groove to the vestibular surface of the symmetrical teeth is the same. 2. A method of orthodontic treatment, taking into account the parameters of the temporomandibular joint, using tele-roentgenography and determining the angles of SNA, SNB, ANB, the inclination of the occlusal plane, recording the parameters of the sagittal and transverse articular path using an axiograph, characterized in that the apparatus is installed according to claim 1 made using a digitized model of the patient’s dentition taking into account the individual parameters of the temporomandibular joint.

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