RU2784783C1 - Method for assessing occlusal relationships of dentitions - Google Patents

Abstract

FIELD: dentistry.

SUBSTANCE: invention relates to medicine, in particular, to a method for assessing occlusal relationships of dentitions. The maxillary and mandibular dentitions are scanned using an intraoral scanner in the position of habitual occlusion; the digital images of the dentitions are uploaded into the virtual space of the CAD/CAM software, and the function of point imaging of occlusal contacts is activated. The number of occlusal contacts (OC) is determined, and the index of loss of occlusal contacts (ILOC) of the dentitions is calculated by the formula: ILOC=OC/Nx100%, wherein N is 52 if OC is not visualised on the incisors and N is 60 in other cases; if ILOC is less than 60%, the level of loss of occlusal contacts of the dentitions is considered high, if it is 60% to 85% — average, if it is 85% or more — low.

EFFECT: possibility of improving the quality of orthopaedic treatment of patients due to the higher accuracy of the assessing occlusal contacts of the dentitions regardless of the number of antagonist teeth, eliminating the risk of errors due to the use of digital technologies and application of the proposed index of loss of occlusal contacts of the dentitions.

1 cl, 15 dwg

Description

The invention relates to medicine, in particular to dentistry, and can be used to assess the occlusal contacts of the dentition in order to improve the quality of orthopedic treatment of patients.

Despite significant advances in the development of modern dentistry, the prevalence of defects in teeth and dentition is still quite high. According to many authors, the main clinical sign of defects in teeth and dentition is a change in the nature of occlusion, which in turn can become one of the factors in the occurrence of various pathological conditions of the dental system, such as dysfunction of the temporomandibular joint and parafunction of masticatory muscles (Yu.A Petrosov, 1989; V. A. Khvatova, 2002; D. Armelin et al., 2004). Occlusal disorders affect the work of masticatory muscles, cause discoordination of their function, disrupt the synchronism of movements in both articular joints of the temporomandibular joint (M.D. Gross, J.D. Matthews., 1986; V.A. Khvatova, 2002; N.D. Mohl, 1997; M. Z. Nassani et al., 2009, E. N. Zhulev, I. V. Velmakina, 2018).

Currently, there are various methods for assessing the occlusal relationship of the dentition, based on determining the area of the available contact points and their number using various materials and devices.

There is a method for determining the quantitative index of the occludedogram obtained using clasp wax and diagnostic models (Abolmasov N.N., 2004). To calculate the index, a three-point system for assessing the closure of each pair of teeth - antagonists is used: 1 point - there are no prints on the occludedogram; 2 points - fuzzy prints; 3 points - clear or through prints. The occludedogram index (OCG) is determined taking into account 14 pairs of antagonist teeth and is calculated by the formula, where the numerator: Σ - the sum of the points × 100; denominator: the highest score multiplied by the number of pairs of teeth - antagonists. For orthognathic bite, the JCG index is 100%. A lower index value indicates an uneven load and the presence of premature occlusal contacts. The disadvantage of this method is the subjectivity of the assessment of the results obtained, as well as the instability of the material used over time, the possibility of deformation of the occludedograms in the oral cavity during the technique and during their storage.

There is another method for assessing occlusal contacts using occlusion charts (RF Patent No. 2375990 "Method for assessing occlusal relationships of teeth"; E.V. Filimonova et al.; 2008). The known method is as follows: using wax, an occlusionogram is obtained in the oral cavity in the position of central occlusion. It is cut along the contours of occlusal contacts to the distal surface of the first permanent molars. The rest of the occlusion chart is weighed on an analytical balance. The volume of the interocclusal space is calculated by the formula V=m/p, where V is the volume of the occlusion chart, m is the mass of the occlusion chart, p is the density of the wax used to obtain the occlusion chart. Evaluate the occlusal relationships of antagonistic teeth, given that the volume of interocclusal space for persons with physiological occlusion is 0.99±0.01 cm ³ . The method allows to increase the reliability of the obtained biometric characteristics, the accuracy of the quantitative measurement of the occlusal relationship of antagonistic teeth. However, the disadvantages of this method are its complexity, laboriousness, the presence of errors associated with the preparation of the occludedogram and the subjectivity of the calculations.

There is a known method for the index assessment of occlusal contacts of the posterior teeth, proposed in 2018 by N.N. Abolmasov (RF Patent No. 2684182). The essence of this method is as follows: after thorough drying of the teeth with air, to assess the localization of occlusal contacts, a double-sided horseshoe-shaped articulation paper (for example, Baush) with a thickness of 100 microns is applied to the teeth of the lower jaw. The patient closes his teeth, on the occlusal surface of the dentition there are imprints that are photographed and digital photographs are taken. Evaluation of occlusal contacts and digital recording is carried out in the form of three numbers separated by commas. The first of them means the maximum number of contacts with the participation of canines, the second - the number of contact points with the participation of premolars, the third - molars (with the exception of the eighth teeth). All contact points on the lateral teeth of the lower jaw are counted and compared with the norm data - 2, 12, 20, in total - 34. A lower value of one of the index components indicates changes in the occlusal scheme.

The disadvantages of the known method is the error in the use of articulation paper with different force of teeth closing, insufficient dryness of the working field, and the absence of clear color prints in the presence of orthopedic structures with ceramic veneer due to their high smoothness.

A known method for determining the area of occlusal contacts, proposed by L.Sh. Karakotova (2009), which consists in the following: 8 µm articulation paper was glued to a strip of adhesive plaster cut to the shape of the dental arch and inserted into the patient's oral cavity. The patient closed his teeth in the position of habitual occlusion, while imprints appeared on the adhesive plaster. This imprinted adhesive patch strip was scanned and analyzed using Adobe Photoshop and Universal Desktop ruler V2.8.111 software, which calculated the area of occlusal contacts in the position of central or habitual occlusion. The main disadvantage of this method is also the possibility of an error due to the use of adhesive plaster and articulating paper, as well as insufficient dryness of the working field.

For an accurate quantitative assessment of occlusal contacts in various pathological conditions of the dental system, it is necessary to understand the existing variants of the norm. It should be noted that studies on the study of the number of contact points between antagonistic teeth are very few, and the number of closure points itself varies depending on the severity of the anatomical shape of the teeth, the presence of abrasion facets, age, and other factors.

According to V.Yu. Milikevich (1984), the number of contact areas of antagonistic teeth in the lateral sections on the right and left (including premolars and molars) is 48: three contact areas on the chewing surfaces of these teeth. According to T. Roberson (2006), there are 26 contact points between the dentition of the upper and lower jaws, taking into account all groups of teeth. I.Yu. Lebedenko et al. indicate the presence of 7 points of occlusal contacts in the region of the anterior group of teeth, including 4 incisors of the upper and 4 incisors of the lower jaws, 20 points of contact in the region of the premolars and 33 in the region of the molars on the right and left on both dentitions, which in total is 64 occlusal contacts . This characteristic of the number of contacts between the teeth refers to the orthognathic occlusion in the presence of the occlusal scheme "1 tooth - 2 antagonists".

Pankey L.D. the average anatomical variant of the structure of the occlusal surface of the teeth was taken into account: there are 8 contact points between the incisors of the upper and lower jaws, 4 between the canines, 16 between the premolars, 32 between the molars (excluding third molars). violation of the integrity of the dentition in this case is 60.

The task is to develop a method for assessing the occlusal relationship of the dentition for planning further treatment.

EFFECT: improving the quality of orthopedic treatment of patients by increasing the accuracy of assessing the occlusal contacts of the dentition, regardless of the number of teeth of the antagonists, eliminating the risk of errors due to the use of digital technologies and the use of the proposed index of loss of occlusal contacts of the dentition.

The technical result is achieved by the fact that in the method, including scanning the dentition of the upper and lower jaws using an intraoral scanner, scanning the dentition in the position of habitual occlusion, digital images of the dentition are loaded into the virtual space of the CAD / CAM software and the function of point visualization of occlusal contacts is activated , determine the number of occlusal contacts (OC), calculate the index of loss of occlusal contacts (IPOC) of the dentition according to the formula: IPOC = OK / Nx100%, where N is 52, if OK is not visualized on the front teeth, and N is 60 - in other cases , with IPO less than 60%, the level of loss of occlusal contacts of the dentition is considered high, from 60% to 85% medium, with 85% or more - low.

The method is carried out as follows.

The dentitions of the upper and lower jaws are scanned using an intraoral scanner and digital images are obtained. The dentition closure is scanned in the position of habitual occlusion. Digital images of the obtained scans of the dentition are loaded into specialized CAD / CAM software, where the function of point visualization of occlusal contacts is activated. The number of occlusal contacts (OK) on the occlusal surfaces of the upper and lower dentition is determined. Calculate the index of loss of occlusal contacts (IPOC) of the dentition according to the formula: IPOC=OK/Nx100%, where N is 52, if OK is not visualized on the front teeth and N is 60 - in other cases. With an IPO less than 60%, the level of loss of occlusal contacts of the dentition is considered high, from 60% to 85% medium, with 85% or more - low. Based on the obtained index value, the volume of further treatment is planned.

A BRI value of less than 60% is an indication for restoring the continuity of the dentition with various options for partial dentures or fixed dentures based on dental implants. The index value from 60% to 85% is an indication for prosthetics of defects in teeth and dentitions with fixed dentures. When the value of IPOC is 85% or more, occlusal correction is possible with the help of selective grinding, the use of direct or indirect restorations.

Marking of occlusal contacts in specialized software is carried out using color fields, in which each color corresponds to a certain distance between the antagonist teeth. Normally, all marked points of occlusal contacts on digital images of the dentition should be uniform in area and color intensity. A change in color towards a decrease in the distance between the antagonist teeth, an increase in the area of the painted surface, and the absence of closure points on individual pairs of antagonists indicate an occlusal imbalance and the presence of supercontacts. Screenshots of digital images of the upper and lower jaws with marked occlusal contacts are printed and selective grinding is carried out in the area of identified supercontacts. At the same time, the anatomical landmarks of the teeth are visible, which improves the accuracy of the correction.

Clinical example No. 1.

Patient M., aged 52, came to the clinic for a preventive examination. On the first visit, digital images of the patient's dentition were obtained using the intraoral (intraoral) scanner iTero Cadent (USA)

Digital images of the dentition were loaded into the virtual space of the DentalCAD 2.2 Valletta software and the function of point visualization of occlusal contacts was activated. Then screenshots of digital images of the upper and lower jaws with marked occlusal contacts were obtained. There were 26 occlusal contacts on the maxillary teeth and 25 on the mandibular teeth (Fig. 1). Total number of OK=26+25=51. Since the occlusal contacts on the anterior teeth were visualized in this patient, N was taken equal to 60, IPOC=51/60x100%=85%, which means that there was a loss of 15% of the occlusal contacts of the dentition, the loss of occlusal contacts is low. A supercontact was revealed in the area of 1.7 tooth. The patient requires selective grinding in order to normalize the interocclusal interaction. The supercontact has been ground. Evaluation of the occlusal relationship of the dentition according to the proposed method was repeated. There were 30 occlusal contacts on the maxillary teeth and 28 on the mandibular teeth (Fig. 2). The total number of contacts was 30+28=58. IPOC=58/60x100%=96.6%, which means the normalization of interocclusal interaction and indicates the correct choice of treatment tactics.

To verify the correctness of the proposed method, additional studies were carried out using T-ScanIII (Tekscan). The following data was received:

During the initial assessment, an imbalance of occlusal forces (39.5% - 60.5%) between the left and right halves of the dentition and supercontact in the region of 1.7 tooth were revealed (Fig. 3).

When assessed after grinding - the distribution of forces between the right and left sides was 48.8% and 51.2%, respectively, supercontact in the region of 1.7 tooth was eliminated (Fig. 4).

Thus, the effectiveness of the proposed method for assessing the occlusal relationships of the dentition using digital technologies was confirmed using computer analysis of occlusion with the T-ScanIII apparatus.

Clinical example No. 2.

Patient M., 45 years old, came to the clinic with complaints about the absence of teeth in the upper and lower jaws. On the first visit, scans of the dentition of the upper and lower jaws were obtained and the position of habitual occlusion was recorded using the intraoral scanner 3 Shape Trios 3 (Fig. 5-7).

After the scans were acquired, the function of occlusal contact analysis (point visualization) in the specialized Trios 3 software was activated and the number of occlusal contacts on the dentition of the upper jaw (Fig. 8) and the lower jaw (Fig. 9) was counted.

Visualization of occlusion was carried out in specialized software Trios 3 using color coding. When counting occlusal contacts, the following data were obtained: the number of contacts on the upper jaw was 15, on the lower jaw - 21, which gives a total number of occlusal contacts 15+21=36.

Since this patient had occlusal contacts in the anterior region, then N=60, IPOC=36/60x100%=60%, and rated as medium, which means that there was a loss of 40% of the occlusal contacts of the dentition and it is possible to carry out occlusal correction using fixed orthopedic structures.

Clinical example No. 3.

Patient O., 48 years old, came to the clinic of orthopedic dentistry with complaints of unsatisfactory appearance of the teeth of the upper jaw, an aesthetic defect, exposure of the roots of the front teeth of the upper and lower jaws. Scanning of the dentition and the position of habitual occlusion was carried out with an intraoral scanner 3 Shape Trios 3, digital models were obtained (Fig. 10, 11).

Then, using the visualization function of occlusal contacts, they were counted for the dentition of the upper jaw and the dentition of the lower jaw. At the same time, only 15 points of occlusal contacts were identified on the upper jaw, and 12 on the lower jaw (Fig. 12). The total total number of contacts was 12+15=27. At the same time, there was a lack of occlusal contacts on the anterior teeth (open bite in the anterior region), therefore N=52, IPOC=27/52x100%=51.9%, and rated as medium, which indicates a loss of 48.1% of occlusal contacts and the need for reconstructive dental treatment.

Clinical example No. 4.

B., aged 55, came to the clinic with complaints of missing teeth and impaired chewing function. To plan orthopedic treatment, scans of the dentition of the upper and lower jaws and habitual occlusion were obtained using the intraoral scanner iTero Cadent (USA). Next, the visualization function of occlusal contacts was activated in the specialized software DentalCAD 2.2 Valletta and the number of contact points of antagonist teeth was counted (Fig. 13).

Since contacts in the anterior dentition were visualized in this clinical case, N=60. The number of points of contact of the teeth on the upper jaw 6 and the lower jaw 6, the total number of points of contact of the teeth - 6+6=12, IPOC=12/60x100%. The index was 20%, rated as high, which indicates the loss of 80% of occlusal contacts.

The patient underwent orthopedic treatment with fixed dentures based on implants installed in the area of missing teeth in the upper and lower jaws. After the completion of prosthetics, scans of the dentition of the upper and lower jaws and habitual occlusion were obtained using the intraoral scanner iTero Cadent (USA). Next, the visualization function of occlusal contacts was activated in the DentalCAD 2.2 Valletta software and the number of contact points of antagonist teeth was counted (Fig. 14).

Since in this clinical case, contacts were visualized in the anterior dentition, the calculation of the loss of occlusal contacts index was carried out taking into account N=60. At the same time, the total number of points of contact of the teeth on the upper and lower jaws was 52.

IPOC=52/60x100%=86.7%, assessed as low.

After the end of the orthopedic treatment, the occlusion was recorded using T-ScanIII (Fig. 15).

An increase in the index of occlusal contacts, the absence of supercontacts and a uniform distribution of occlusal forces between the right and left sides (45.7% and 54.3%, respectively), revealed during computer analysis of occlusion using T-ScanIII, indicates the normalization of interocclusal interaction and the correctness of the choice treatment tactics.

The index of loss of occlusal contacts of the dentition, proposed by us, in contrast to the prototypes, should be recognized as the most highly accurate due to the use of modern digital technology for visualizing the occlusal contacts of antagonistic teeth. The calculation of the index is simple and does not take much time.

The method for evaluating the occlusal relationships of the dentition allows determining indications for orthopedic treatment, visually assessing the uniformity of the distribution of occlusal contacts, identifying premature contacts, and effectively performing selective grinding of teeth in order to normalize interocclusal interaction. In addition, the calculation of the index of loss of occlusal contacts of the dentition before and after orthopedic treatment allows you to control its effectiveness, and the use of digital technologies allows you to create a database for the study of one patient, which facilitates its storage and ensures control of the dynamics of the disease.

Claims (1)

A method for assessing the occlusal relationship of the dentition, including scanning the dentition of the upper and lower jaws using an intraoral scanner, scanning the dentition in the position of habitual occlusion, characterized in that digital images of the dentition are loaded into the virtual space of the CAD / CAM software and the point visualization function is activated occlusal contacts, determine the number of occlusal contacts (OC), calculate the index of loss of occlusal contacts (IPOC) of the dentition according to the formula: IPOC = OK / Nx100%, where N is 52, if OK is not visualized on the front teeth, and N is 60 - in in other cases, with an IPO less than 60%, the level of loss of occlusal contacts of the dentition is considered high, from 60% to 85% - medium, with 85% or more - low.

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