RU2423912C2 - Method of predicting complications after prosthetics of teeth with secondary adentia - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to dentistry. On orthopantomogram conventional lines are drawn at the level of apexes, parallel to chewing surfaces of examined and contralateral teeth. From the points, differentiating intra- and extra-alveolar parts of teeth perpendiculars are dropped on the conventional lines, parallel to teeth chewing surfaces. Borders of projections of intra-alveolar parts of examined and contralateral teeth are determined. From the centre of projection of intra-alveolar parts (O^' and O) built are perpendiculars, whose intersection with chewing surfaces are points A' and A. Drawn is line, corresponding to occlusal plane, parallel to it conventional line at the level of apexes. From point O drawn is perpendicular on occlusal plane, obtaining angle A'O'B'. From point O^' drawn is perpendicular on occlusal plane (point B'), obtaining angle A'O'B'. Difference obtained in comparison of angles AOB and A'O'B' is convergence angle. From point A perpendicular is dropped on conventional line, parallel to occlusal plane (point D). From point A^' perpendicular is dropped on conventional line, parallel to occlusal plane (point D'). Points D' and D are connected with gravity centre of examined tooth (point C), obtaining triangles OCD and O'CD'. On examined tooth built is triangle D'CD, in which segment CD is taken for resultant of acting moments of forces - RAMF of examined tooth. In case if RAMF direction does not go beyond the boundaries of projection of intra-alveolar surface of examined tooth on conventional line, parallel to chewing surface, and amount of gingival fluid corresponds to intact periodentium or periodentium, in which preclinical changes are possible, risk of complications development is excluded.

EFFECT: invention can be applied for prediction of complications after prosthetics of teeth in patients with secondary partial adentia.

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Description

The invention relates to medicine, namely to dentistry. Before restoring the continuity of the dentition, the patient is assessed for supporting teeth based on an x-ray, and also taking into account the coefficients of tooth mobility according to T.S. Fleszar. However, the resolution of the roentgenogram at the early stages of the development of the pathological process in the periodontium is not high enough, perhaps its subjective interpretation. Based on the roentgenogram and tooth mobility coefficient according to T.S. Fleszar, it is impossible to assess the functional state of the dentofacial system, its reserve capabilities.

In the existing diagnostic systems, all the clinical conditions of periodontal disease are examined according to the degree of proximity to some selected pattern, which has homogeneous values in the overwhelming majority of healthy people, which are a peculiar characteristic of the Homo sapiens species. In this case, as a rule, individual characteristics are lost. According to known data (Zhidkikh ED Systematic evaluation of the effectiveness of complex treatment of generalized forms of periodontitis: Dis .... Dr. med. / Medical Academy of Postgraduate Education. - St. Petersburg, 2000. - P.111.) In the normal axis of the upper posterior teeth have a slope of 6 ° to 10 °. In the lower jaw, this indicator varies from 6 ° to 25 °. The paper does not indicate how physiological one or another angle of inclination is. There is also no information about the extent to which the additionally acquired value of the angle is pathogenic.

In medical practice, patients with defects in the dentition prevail. Ignoring the traumatic component of periodontal diseases, which consists in the absence of therapeutic measures aimed at restoring the integrity of the dentition, often leads to relapse, and in other cases to an aggravation of the clinical situation. If the doctor took into account the traumatic component of the periodontal status of the patient, then the adaptation and rehabilitation process, which is implemented in the periodontal complex, was controlled conditionally, subjectively.

Chewing load in physiological conditions (pronounced approximate contacts throughout the dentition) is a stimulator of metabolic processes in the periodontium. The presence of a defect in the integrity of the dentition adversely affects periodontal tissue. The resulting moment of forces tends to “knock over” the tooth. In the wall of the alveoli there are stresses "compressive" and "tensile", the greatest in the cervical and supraheal zones. A tooth changes its spatial orientation relative to other teeth and the occlusal plane. Tooth tilting has a significant impact on medical tactics when evaluating indications for the choice of medical designs and clarifying the amount of necessary therapy (Manual on orthopedic dentistry. Edited by V.N. Kopeikin et al. - M, Medicine, 1998. - 520 s; Chuyko AN, Vovk VE Features of biomechanics in dentistry. - Kharkov, "Prapor", 2006. - 300 p.).

A known method for predicting complications after prosthetics of teeth with secondary partial adentia, characterized in that the patient after periodontal treatment determines the amount of gingival fluid in the area of teeth defining the defect, and then determine the convergence angle of each of these teeth, equal to the difference in the values of the angle of inclination of the studied tooth and the tooth of the same name in the opposite jaw, and with the amount of gingival fluid corresponding to the intact periodontium, and the angle of convergence of the teeth up to 5 degrees, the risk of complications is excluded (Pat. No. 2289358 of the Russian Federation. IPC А61С 19/04. A method for predicting complications after prosthetics with secondary partial adentia. Kopytov AA / GOU VPO Mosk. gos.mediko-stomat.un-t. Publ. 2006.). This method is selected for the prototype.

The disadvantages of this method are:

- the impossibility of patients with severe deformations of the dentition to adequately install devices by which they determine the position of the occlusal plane, orienting the jaw model on the parallelometer table in the right direction, which reduces the accuracy of the measurements;

- when performing calculations based on the determination of the occlusal plane, it is impossible to correctly plan the rehabilitation of periodontal tooth complexes, the chewing surface of which formed an angle with the occlusal plane of more than 20 °. In relation to the occlusal plane, the chewing surfaces of the teeth are inclined differently. The projection of the intra-alveolar part of the tooth (bearing area) is normal with pronounced interdental contacts on a plane parallel to the chewing surface of the tooth, true (maximum). When projecting the intra-alveolar part of the tooth on a plane parallel to the occlusal plane, the area decreases. The difference between the values of the projection areas depends on the angle between the occlusal plane and the chewing surface. As the angle increases, the error also increases. With an angle of more than 20 °, clinically determined inconsistencies occur;

- convergence was determined without taking into account the initial axis of the tooth (physiological position). Previously, the calculation was made from the vertical (the rod was strengthened vertically in the parallelometer socket), but if you count from the vertical, there is no way to take into account the buccal-lingual-palatal inclination;

- the physiological direction of the resulting acting force moments (RVMS) and its change with the acquisition of the angle of convergence, in relation to the boundaries of the support, which, in fact, is a change in stability, were not determined;

- a change in tooth stability was defined as a change in its mobility, pathogenetic mechanisms of loss of stability were not determined that arise due to a decrease in the support area during atrophic changes in the alveolar bone and / or due to a change in the strength characteristics of periodontal tissues, i.e. changes in the compliance of periodontal tissues, including due to infectious effects.

The objective of the invention is to improve the accuracy of predicting complications in adaptation and rehabilitation processes occurring after restoration of occlusal ratios in patients with secondary partial adentia by determining tooth stability.

The technical result consists in determining the stability of the tooth, planned as a support for the bridge. This is achieved due to the fact that the intra-alveolar angle of convergence of each tooth, limiting the defect of the dentition, is determined, the direction of the resulting acting moments of force is determined, and if it does not go beyond the boundary of the projection of the intra-alveolar part of the tooth on a conditional line parallel to the chewing surface and the amount of gingival fluid corresponds to an intact periodontal or periodontal, in which preclinical changes are possible, the risk of complications is excluded.

The dynamics of periodontal tissue rehabilitation, or lack thereof, was determined using a well-known technique based on the study of gingival fluid characteristics and allowing to determine the minimum changes that occur in periodontal tissues (E.S. Halitova. Quantitative and qualitative gingival fluid parameters are normal and - in case of pathology periodontal tissues: Dis .... k.m.s. / N.A.Semashko Moscow Medical Dental Institute. - 1989.- 173 s). Based on the study, a group of individuals was determined whose periodontal period was considered intact, in accordance with other diagnostic systems, based on the amount of gingival fluid received, and to more accurately state the dental status, the group was divided into two subgroups: a subgroup of individuals with an intact periodontal period and a subgroup with an intact periodontium in which preclinical changes are possible.

In patients with complete dentition, in different phases of occlusion, according to the theory of articulation equilibrium, PBMC is coaxial to the axis of the tooth and is directed to the middle of the projection of the intra-alveolar part of the tooth on a plane parallel to the chewing surface. In case of loss of approximate contact, the chewing load initiates and stimulates the occurrence of a convergence angle, the direction of the PBMC changes. Depending on the installation of the tooth axis, it can be concluded that the support function (tooth stability, since the PBMC tends to the border of the projection of the intra-alveolar part of the tooth) is impaired, which in turn indicates the possibility of achieving and the nature of the process of rehabilitation of periodontal teeth planned for support bridge prosthesis.

The study involved persons with a unilaterally included defect in the integrity of the dentition. After periodontal treatment, having achieved stabilization of the infectious component, the dynamics of the exudation of the gingival fluid depended on the load-bearing damage to the periodontal tissues. Elements depicted in figures 1-7:

- conditional line parallel to the chewing surface 1

- PBMC 2

- apical point of the root of the tooth (for multi-rooted teeth - the center of the projection of the intra-alveolar part of the tooth) 3

- the center of gravity of the tooth C4

- axis of the tooth 5

- projection of the intra-alveolar part of the tooth 6

- tooth convergence angle 7

- decrease in the projection area of the intra-alveolar part of the tooth ΔL8

- intra-alveolar part of the tooth 9

- chewing surface 10

- points delimiting extra- and intraalveolar parts of the tooth 11

- perpendiculars to conditional lines parallel to the chewing surfaces of the teeth 12

- the initial axis of the installation of the tooth O'A '13

- the changed axis of the tooth installation О А 14

- occlusal plane 15

- conditional line at the apex level, parallel to the occlusal plane 16

- perpendiculars O'B 'and OV from the centers of projections of the intra-alveolar parts of the teeth on the occlusal plane 17

- points B, B 'receiving a perpendicular from points O, O' located on the occlusal plane 18

- angle A'O'B '- the initial angle of installation of the tooth 19

- angle AOW - the changed angle of the tooth 20

- points A, A 'of the chewing surface - the beginning of the perpendicular to a conditional line parallel to the occlusal plane 21

- perpendiculars from points A, A 'to a conditional line parallel to the occlusal plane 22

- points D, D ', in which the direction of the PBMC falls, located on a conditional line parallel to the occlusal plane 23

- segment OD - the geometric value of the transverse component of the PBMC of the studied tooth 24

- segment O'D '- the geometric value of the transverse component of the PBMC of the contralateral tooth 25

- segment DD '- the difference in the values of the transverse component of the PBMC (determined by the geometric combination of the original and changed axes of the installation of the studied tooth) 26

- angle O'CD 'of the initial installation of the studied tooth 27

- angle OSD of the modified installation of the studied tooth 28

- intra-alveolar angle of convergence of the studied tooth D'CD 29

- forces applied to the chewing surface of the tooth, successively transferred to a point corresponding to the center of gravity of the tooth;

(the geometrical sum of these forces characterizes the direction of the PBMC) 30, 31. With the loss of integrity of the dentition, under the influence of chewing load, the axis of the teeth are moved. To measure the amount of displacement, and it regulates the possibility of achieving the rehabilitation process, it is necessary to determine the point relative to which the displacement will be determined. For this, the apical root point or the center of the projection of the intra-alveolar part of the tooth (for multi-root teeth) is most suitable; it changes its location less than any other point of the tooth during the patient’s life. It is logical to calculate the displacement according to the excursion of the center of gravity of the tooth (C 4). Solving problems of this class, the tooth is considered as a triangular-shaped physical body whose center of gravity is located at the intersection of medians (L.D. Landau, A.I. Kitaygorodsky Physics for All. - Moscow: Nauka, 1974 - P.132. ) The center of gravity of multi-rooted teeth is located 2 mm coronary to the bifurcation.

As the studies showed, with the localization of the center of gravity of the studied tooth, limiting the integrity defect of the dentition, in a position corresponding to the center of gravity of the contralateral tooth located in the part of the dentition with pronounced approximate contacts, and the direction of the PBMC, within the projection area of the intra-alveolar part of the examined tooth on a conditional line parallel to the chewing surface of the tooth under study, the pine orientation of the RVMS of the contralateral tooth, the implementation of the specified chewing loading does not cause a significant increase in gingival fluid exudation. Under these conditions, there is no mechanical damage. An increase in exudation can also occur due to infectious damage, however, when carrying out the proposed method for predicting the amount of gingival fluid is determined after periodontal treatment, excluding this factor. The prognosis is considered favorable in the absence of mechanical damage, i.e. when the direction of the resulting acting moments of forces does not extend beyond the boundary of the projection of the intra-alveolar part of the tooth. Outside the border - as unfavorable.

The localization of the center of gravity of tooth C 4 relative to the boundaries of the projection of the intra-alveolar part of the tooth onto a plane parallel to the chewing surface is different in different phases of occlusion and is defined as changing tooth stability. The increase in the distance between the center of gravity of the tooth and the support occurs due to the transition of the center of gravity to a more extra-alveolar position, due to the apical movement of the border of the periodontal attachment.

In the absence of approximate contacts, with a constant force and direction of action of the chewing load, the strength characteristics of the periodontium change due to load damage. As the load damage increases, clinically determined atrophic changes in the alveolar bone develop, periodontium loses the opportunity to achieve rehabilitation. The reason for this is a change in the direction of the transverse component of the PBMC.

In the segment of the dentition with pronounced approximate RVMS contacts, it is aligned with the axis of the tooth installation, as evidenced by the integrity of the closing compact alveolar plate. In the process of occlusion during coincidence of the axis of installation of the tooth and PBMC, the moment of force will be zero. The absence of the transverse component of the chewing load ensures uniform loading of the periodontium - maximum tooth stability.

The axis of the tooth origin originates at the apical point of the root O. For multi-rooted teeth, it is in the center of the projection of the intra-alveolar part of the tooth onto a conditional line parallel to the chewing surface. To determine the axis of the tooth installation, it is necessary to build a perpendicular from point O, located on a conditional line parallel to the chewing surface.

In the segment of the dentition with lost proximal contacts, PBMC changes direction according to the value of the intraalveolar angle of convergence. Having determined the angle that distinguishes the initial axis of the tooth installation and the changed axis of the tooth installation, we obtain the geometric value of the transverse component of the RVMS of the tooth, limiting the integrity of the dentition.

Chewing surfaces of teeth located in segments of the dentition with pronounced proximal contacts have a different inclination with respect to the occlusal plane, which is a sign of the functional usefulness of occlusion. Given the occlusal curves and the different spatial orientation of the chewing surfaces of the teeth, it became possible to increase the accuracy of prediction by calculating the intra-alveolar convergence angle. In the part of the dental arch with lost approximate contacts, the inclination of the chewing surface of the tooth, relative to the occlusal plane, increases. Accordingly, the boundaries of the projection of the intra-alveolar part of the tooth and the localization of the apical root point, which is the reference point, change.

Previously, the convergence angle was determined on the scale of the protractor, fixed with a vertical rod in the socket of the parallelometer. Determination of the intra-alveolar angle of convergence allows us to consider the issue of tooth stability, the tooth is not stable from probabilistic positions or not, but to show the extent to which the tooth in the segment of the dentition with pronounced approximate contacts is more stable compared to the tooth located in the segment with a defect in the integrity of the dentition . The intra-alveolar convergence angle is equal to the difference between the angle formed by the perpendicular drawn from the center of the projection of the intra-alveolar part of the tooth on a conditional line parallel to the chewing surface and the resulting effect of the moment of forces of the tooth under study with the apex at the center of gravity of the tooth and the angle of initial installation of the contralateral tooth.

The proposed method is as follows.

After stabilization by the periodontic treatment of the infectious component, the patient is determined by the amount of gingival fluid in the area of the teeth limiting the dentition defect (for example, according to the tables proposed in the study of Halitova E.S.). After that, an orthopantomographic study is performed (for example, using the Kranex orthopantomograph). On the orthopantomogram (Figs. 1-3), conditional lines 1 are drawn at the apex level, parallel to the chewing surfaces 10, of the test and contralateral teeth, from the points delimiting the intra- and extra-alveolar parts of these teeth 11, the perpendiculars 12 are lowered to the conditional lines 1, getting the boundaries projections of the intra-alveolar part 6 of these teeth; Perpendiculars are built from the center of the projection of the intra-alveolar part 3, which are the initial axis of the installation of the contralateral tooth O'A '13 and the changed axis of the OA of the studied tooth 14. Lines 10 and 1 are parallel, which determines the position of points A and A' (according to the property of parallel lines, since 13 and 14 are perpendicular to line 1). A line is drawn (Fig. 4), corresponding to the occlusal plane 15, and a conditional line parallel to it at the level of the apexes 16; perpendicular 17 is drawn from point O 3 to point B 18; the magnitude of the angle AOW is the altered installation angle of the investigated tooth 20; Perpendicular 17 is drawn from point O '3 to point B' 18, the angle A'O'B '19 is the initial angle of installation of the contralateral tooth; the difference obtained by comparing the angles of AOB and A'O'B 'is the angle of convergence 7. From points A and A' 21 (Fig. 5), perpendiculars AD and A'D '22 are built to points D and D' 23 on the conditional a line parallel to the occlusal plane 16 (since lines 15 and 16 are parallel, and AD and A'D 'are perpendiculars, the localization of points D and D' is determined according to the property of parallel lines). The obtained segment O'D '25 is the geometric value of the inclined components of the PBMC of the contralateral tooth, and the segment OD 24 is the examined tooth obtained after combining the segment DD' 26, is the geometric difference of the inclined components of the PBMC of the studied tooth, (Fig.6-7) connecting the points D and D 'with the center of gravity C 4 of the examined tooth, determine the angle of the initial installation of the contralateral tooth O'CD' 27 and the angle of the modified installation of the examined tooth OCD 28, calculate the difference in the values of these angles, i.e. Intraalveolar angle of convergence. In the resulting triangle D'CD, the segment CD is RVMS 2 of the studied tooth and if the orientation of the RVMS does not extend beyond the projection of the intra-alveolar part of the studied tooth 6 on a conditional line parallel to the masticatory surface 1, and the amount of gingival fluid corresponds to an intact periodontal or periodontal period in which preclinical changes, the risk of complications are excluded.

Clinical example No. 1

Patient B., 28 years old, turned to the dentist about the prosthetics of the included defect in the dentition of the lower jaw, on the right limited to 34 and 37 teeth.

Complaints: difficulty chewing food.

Anamnesis: A course of treatment was conducted in the periodontology department. 35 tooth was removed five years ago, 36 - in the current year.

Objectively: The maxillary dentition is complete, approximate contacts are expressed. Missing 35, 36 teeth. The RMA index is 4.7%. Hygienic index - 1 - absence of inflammation. The depth of sounding of the gingival grooves is 1.0-3.0 mm. In the area of 37 teeth - 3.5 mm. The Miller tooth mobility in the Fleszar modification is 0, X-ray: in the region of 34 and 37 teeth, the integrity of the trailing cortical plate is broken. After stabilization with periodontal treatment of the infectious component, the patient was determined the amount of gingival fluid in the region of 34 and 37 teeth, limiting the defect of the dentition (according to the tables proposed in the study of Halitova E.S.). It turned out that in the tooth region 34 the amount of gingival fluid corresponds to the values characteristic of an intact periodontium, and in the tooth region 37 the amount of gingival fluid corresponds to the upper boundary of the periodontal interval in which preclinical changes are possible. Then an orthopantomographic study was performed (using the Kranex orthopantomograph).

The intra-alveolar angle of convergence of the 34 tooth was determined as follows: on the orthopantomogram (Figs. 1-3), conditional lines 1 were drawn at the apex level, parallel to the chewing surfaces of the examined 34 and the contralateral 44 teeth, from the points delimiting the intra- and extra-alveolar parts of these teeth 11, were omitted perpendiculars 12 to conditional lines 1, getting the boundaries of the projection of the intra-alveolar part 6 of these teeth; perpendiculars were constructed from the projection center of the intra-alveolar part 3, which are the initial installation axis of the contralateral 44 tooth 13 and the changed installation axis 34 of the tooth 14. A line (Fig. 4) corresponding to the occlusal plane 15 was drawn and a conditional line parallel to it at the apex level 16; perpendicular 17 was drawn from point O 3 to point B 18; the magnitude of the angle AOB is the changed installation angle of the examined 34 tooth 20; Perpendicular 17 was drawn from point O '3 to point B' 18, the angle A'O'B '19 is the initial angle of installation of the contralateral 44 tooth; the difference obtained by comparing the angles of AOB and A'O'B 'is the angle of convergence 7. From points A and A' 21 (Fig. 5) we built perpendiculars AD and A'D '22 to points D and D' 23 on a conditional line parallel to the occlusal plane 16. The obtained segment O'D '25 is the geometric value of the inclined components of the PBMC of the contralateral tooth, and the segment OD 24 is the examined tooth obtained after combining the segment DD' 26 is the geometric difference of the inclined components of the PBMC of the studied tooth (Fig.6- 7), connecting the points D and D 'with the center of gravity C 4 of the tooth under study, determined the values initial angle setting contralateral tooth O'CD 'and value 27 changes the setting of the test OCD tooth angle 28 calculated difference values of these angles, i.e., Intraalveolar angle of convergence. In the resulting triangle D'CD, the segment CD is RVMS 2 of the studied tooth, its orientation of the RVMS does not go beyond the boundaries of the projection of the intra-alveolar part of the studied tooth 6 on a conditional line parallel to the chewing surface 1.

The intraalveolar angle of convergence of the 37 tooth was determined as follows: on the orthopantomogram (Figs. 1-3), conditional lines 1 were drawn at the apex level, parallel to the chewing surfaces of the examined 37 and contralateral 47 teeth, from the points that delimit the intra- and extra-alveolar parts of these teeth 11 were omitted perpendiculars 12, on conditional lines 1, getting the boundaries of the projection of the intra-alveolar part 6 of these teeth; perpendiculars were constructed from the projection center of the intra-alveolar part 3, which are the original installation axis of the contralateral 47 tooth 13 and the modified installation axis 37 of the tooth 14. Draw a line (Fig. 4) corresponding to the occlusal plane 15, and a parallel conditional line at the apex level 16; perpendicular 17 was drawn from point O 3 to point B 18; the magnitude of the angle AOB is the changed installation angle of the investigated 37 tooth 20; Perpendicular 17 was drawn from point O '3 to point B' 18; the angle A'O'B '19 is the initial angle of installation of the counter lateral 47 tooth; the difference obtained by comparing the angles of AOB and A'O'B 'is the angle of convergence 7. From points A and A' 21 (Fig. 5) we built perpendiculars AD and A'D '22 to points D and D' 23 on the conditional a line parallel to the occlusal plane 16. The obtained segment O'D '25 is the geometric value of the inclined components of the PBMC of the contralateral tooth, and the segment OD 24 is the examined tooth obtained after combining the segment DD' 26 is the geometric difference of the inclined components of the PBMC of the examined tooth (Fig. 6-7), connecting the points D and D 'with the center of gravity C 4 of the tooth under study, determined the quantities well, the angle of the initial installation of the contralateral tooth O'CD '27 and the angle of the changed installation of the studied tooth OCD 28, we calculated the difference in the values of these angles, i.e. Intraalveolar angle of convergence. In the obtained triangle D'CD, the segment CD is RVMS 2 of the studied tooth, its orientation does not go beyond the boundaries of the projection of the intra-alveolar part of the studied tooth 6 on a conditional line parallel to the chewing surface 1.

Because the direction of the resulting acting moments of forces 34 and 37 of the teeth, limiting the defect of the dentition, does not go beyond the boundaries of the projection of the intra-alveolar part of the tooth on a conditional line parallel to the chewing surface, and the amount of gingival fluid obtained in the region of the tooth 34 corresponds to the intact periodontium, and in the region of 37 periodontal tooth, in which preclinical changes are possible, the risk of complications after prosthetics was excluded. The integrity of the mandibular dentition was restored with a cast metal-ceramic bridge. A circular ledge was formed at the level of the gingival margin. After fixing the bridge, starting from the second day, dynamic monitoring of the exudation of gingival fluid in the region of the abutment teeth was carried out weekly. The area of impregnation of filter paper obtained in the region of 34 and 37 teeth increased to the twenty-third day of observation. Rehabilitation of periodontal tooth complexes 34 and 37, which serve as supports in the bridge, began by the thirtieth day after fixation of the bridge. After two months, the area of impregnation decreased, reaching values characterizing periodontal disease as "periodontal period in which preclinical changes are possible."

Clinical example No. 2

Patient I., 42 years old, turned to a dentist about the prosthetics of the included defect in the dentition of the lower jaw, on the right limited to 34 and 37 teeth.

Complaints: a cosmetic defect, difficulty chewing food.

Anamnesis: Teeth removed "long ago." He wants to complete the prosthetics. Two weeks ago I finished treatment in the therapeutic department.

Objectively: The integrity of the maxillary dentition has been restored by full-fledged metal-ceramic bridges based on 15, 13 and 24, 27 teeth. Missing 35, 36 teeth. The RMA index is 5.3%.

Hygienic index - 1 - absence of inflammation. Sensing depth of gingival grooves: 1.0-3.0 mm. In the area of 37 teeth - exceeds 3.5 mm.

Miller tooth mobility in the Fleszar modification is 0.

Radiographic: in the region of 34 and 37 teeth, the integrity of the trailing cortical plate is impaired. In the area of 34 and 37 teeth, limiting the defect of the dentition, the amount of gingival fluid (according to the tables proposed in the study by Halitova ES) corresponds to the upper boundary of the periodontium interval in which preclinical changes are possible. In order to determine the possibility of using 34, 37 teeth with supports in the bridge, a determination was made of the magnitude of their intra-alveolar convergence angles. The intra-alveolar angle of convergence of the 34 tooth was determined as follows: on the orthopantomogram (Figs. 1-3), conditional lines 1 were drawn at the apex level, parallel to the chewing surfaces of the examined 34 and the contralateral 44 teeth, from the points delimiting the intra- and extra-alveolar parts of these teeth 11, were omitted perpendiculars 12, on conditional lines 1, getting the boundaries of the projection of the intra-alveolar part 6 of these teeth; perpendiculars were constructed from the center of the projection of the intra-alveolar part 3, which are the initial axis of the installation of the counter lateral 34 of the tooth 13 and the changed axis of the installation of the 44 tooth 14. Draw a line (Fig. 4) corresponding to the occlusal plane 15 and parallel to it a conditional line at the level of apexes 16; perpendicular 17 was drawn from point O 3 to point B 18; the magnitude of the angle AOB is the changed installation angle of the examined 34 tooth 20; Perpendicular 17 was drawn from point O'3 to point B '18, the angle A'O'B' 19 is the initial installation angle of the counter lateral 44 tooth; the difference obtained by comparing the angles of AOB and A'O'B 'is the angle of convergence 7. From points A and A' 21 (Fig. 5) we built perpendiculars AD and A'D '22 to points D and D' 23 on a conditional line parallel to the occlusal plane 16. The obtained segment O'D '25 is the geometric value of the inclined components of the PBMC of the contralateral tooth, and the segment OD 24 is the examined tooth obtained after combining the segment DD' 26 is the geometric difference of the inclined components of the PBMC of the studied tooth (Fig.6 -7) connecting the points D and D 'with the center of gravity C 4 of the tooth under study, determined the values at the angle of the initial installation of the contralateral tooth O'CD '27 and the angle of the angle of the changed installation of the studied tooth OCD 28, the difference in the values of these angles was calculated, i.e. Intraalveolar angle of convergence. In the resulting triangle D'CD, the segment CD is RVMS 2 of the studied tooth, its orientation of the RVMS does not go beyond the boundaries of the projection of the intra-alveolar part of the studied tooth 6 on a conditional line parallel to the chewing surface 1.

The intraalveolar angle of convergence of the 37 tooth was determined as follows: on the orthopantomogram (Figs. 1-3), conditional lines 1 were drawn at the apex level, parallel to the chewing surfaces of the examined 37 and contralateral 47 teeth, from the points that delimit the intra- and extra-alveolar parts of these teeth 11 were omitted perpendiculars 12, on conditional lines 1, getting the boundaries of the projection of the intra-alveolar part 6 of these teeth; perpendiculars were constructed from the projection center of the intra-alveolar part 3, which are the original installation axis of the contralateral 47 tooth 13 and the changed installation axis 37 of the tooth 14. Draw a line (Fig. 4) corresponding to the occlusal plane 15 and parallel to it a conditional line at the level of apexes 16; perpendicular 17 was drawn from point O 3 to point B 18; the magnitude of the angle AOB is the changed installation angle of the investigated 37 tooth 20; Perpendicular 17 was drawn from point O '3 to point B' 18; the angle A'O'B '19 is the initial angle of installation of the counter lateral 47 tooth; the difference obtained by comparing the angles of AOB and A'O'B 'is the angle of convergence 7. From points A and A' 21 (Fig. 5) we built perpendiculars AD and A'D '22 to points D and D' 23 on the conditional a line parallel to the occlusal plane 16. The obtained segment O'D '25 is the geometric value of the inclined components of the PBMC of the contralateral tooth, and the segment OD 24 is the examined tooth, obtained after combining the segment DD' 26 is the geometric difference of the inclined components of the PBMC of the examined tooth (Fig.6 -7), connecting the points D and D 'with the center of gravity C 4 of the tooth under study, determined the quantities in the initial angle setting contralateral tooth O'CD '27 and the angle changes the setting of the test tooth OCD 28, calculated difference values of these angles, i.e., Intraalveolar angle of convergence. In the resulting triangle D'CD segment CD is RVMS 2 of the studied tooth, its direction is RVMS

does not go beyond the boundaries of the projection of the intra-alveolar part of the studied tooth 6 on a conditional line parallel to the chewing surface 1.

In 34 teeth, the orientation of the RVMS does not go beyond the projection of the intra-alveolar part of the tooth, and in 37 teeth, the RVMS went beyond the projection of the intra-alveolar part of the tooth on a conditional line parallel to the chewing surface; the amount of gingival fluid in the area of the studied teeth corresponds to the periodontal condition - "periodontal, in which preclinical changes are possible", it is concluded that complications occur after prosthetics. A decision was made to increase the support area of the orthopedic structure, restoring the integrity of the dentition. What informed consent was obtained. The integrity of the mandibular dentition was restored with a cast metal-ceramic bridge with a support of 34, 37 and 38 teeth. A circular ledge was formed at the level of the gingival margin. After fixation of the bridge, starting from the second day, dynamic monitoring of the exudation of gingival fluid in the region of the abutment teeth was carried out weekly. The area of impregnation of filter paper obtained in the region of abutment teeth increased until the sixteenth day of observation, reaching the values of "catarrhal gingivitis." By the thirtieth day of observation, the exudation had stabilized. After two months, the area of impregnation decreased, reaching values characterizing periodontal disease as "periodontal period in which preclinical changes are possible."

Claims (1)

A method for predicting complications after prosthetics in persons with secondary partial adentia, which consists in determining the amount of gingival fluid after periodontal treatment, characterized in that conditional lines at the apex level parallel to the masticatory surfaces of the examined and contralateral teeth are drawn from the points delimiting the intra - and extra-alveolar parts of the teeth, lower the perpendiculars to the conditional lines parallel to the chewing surfaces of the teeth, determine borders of projections of the intra-alveolar parts of the examined and contralateral teeth are drawn, perpendiculars are constructed from the center of the projection of the intra-alveolar parts (O 'and O), the intersections of which with the chewing surfaces are points A' and A, draw a line corresponding to the occlusal plane, parallel to it a conditional line at the apex level , from point O draw a perpendicular to the occlusal plane (point B), getting the angle AOW, from point O 'draw a perpendicular to the occlusal plane (point B'), getting the angle A'O'B ', the difference obtained and comparing the angles AOB and A'O'B ', is the convergence angle, from point A lower the perpendicular to the conditional line parallel to the occlusal plane (point D), from point A' lower the perpendicular to the conditional line parallel to the occlusal plane (point D ' ), connect the points D 'and D with the center of gravity of the tooth under study (point C), obtain triangles OCD and O'CD', then construct a triangle D'CD on the tooth under study, in which the segment CD is taken as the result of the acting force moments - the PBMC of the person under study a tooth; and if the orientation of the RVMS does not go beyond the projection of the intra-alveolar part of the studied tooth on a conditional line parallel to the chewing surface, and the amount of gingival fluid corresponds to an intact periodontal or periodontal period in which preclinical changes are possible, the risk of complications is excluded.

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