RU2749302C1 - Method for layer-by-layer classification of the cross-sectional shape of root canals - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely to dentistry. In particular, it relates to therapeutic dentistry and concerns a method for layer-by-layer classification of the cross-sectional shape of root canals.

EFFECT: new system of layer-by-layer classification of the shape of root canals.

1 cl, 2 tbl, 10 dwg

Description

The invention relates to medicine, namely to dentistry, in particular to therapeutic dentistry and relates to a method for layer-by-layer classification of the cross-sectional shape of root canals.

A method for classifying root canal systems is known from the prior art (Weine, FS, Healey, H. J., Gerstein, N., & Evanson, L. Canal configuration in the mesiobuccal root of the maxillary first molar and its endodontic significance. Oral Surgery, Oral Medicine, Oral Pathology, 1969; 28 (3): 419-425), in which, according to the classification, the canal system at any root is divided into 4 main types: Type 1 - one main course of the canal from the mouth to the apex. Type 2 - two canals in the orifice, merging in the apical third into one, type 3 - two separate root canals and type 4 - one canal in the orifice, which is divided into two in the apical third (see Fig. 1 ).

The disadvantage of this technique is that the proposed four types of root canals are not enough to classify the configuration of the root canals of the first maxillary molars.

A method for classifying the configuration of root canal systems is known from the prior art (Vertucci, F.J. Root canal anatomy of the human permanent teeth. Oral surgery, oral medicine, oral pathology, 1984; 58 (5): 589-599). Eight configurations of the pulp cavity space were divided into eight types. Type I represents a single channel from the pulp chamber to the apex (1). Type II: Two separate canals emerge from the pulp chamber and join in one apical third (2-1). Type III: one canal leaves the pulp chamber and divides into two at the root, which then merge into one (1-2-1). Type IV: two separate canals emerge from the pulp chamber towards the apex (2). Type V: One canal exits the pulp chamber and divides into two separate canals with separate apical foramina (1-2). Type VI: 2 separate canals emerge from the pulp chamber, merge at the root, and again split into two separate canals (2-1-2). Type VII: one canal exits the pulp chamber, divides into two and then connects in the root body and, again, divides into two separate short canals, up to the apex (1-2-1-2). Type VIII: three separate canals from the orifice to the apex (3). (see Fig. 2).

The disadvantage of this technique is the lack of classification of the shape of the root canals.

A method for classifying the shape of the canals and the presence of connections in the canals is known from the prior art (Kim S, Pecora G, Rubinstein R, Dorscher-Kim J: Color Atlas of Microsurgery in Endodontics. 1st ed. Philadelphia: WB Saunders; 2001, 192 pages). the shape of the canal and the presence of connections in the canals in the area of the mouth: Type I - incomplete isthmus; it is a weak communication between two channels. Type II is characterized by two canals with a definite connection between them (complete isthmus). Type III is very short, complete isthmus between two canals. Type IV is a complete or incomplete isthmus between three or more canals. Type V is designated by two or three channel openings with no visible connections between them. (see Fig. 3).

The disadvantage of this technique is that it describes the slit-like shape of the channels only in the area of the mouth.

The technical result of the present invention is a system for layer-by-layer classification of the shape of root canals.

The technical result is achieved due to the fact that the method of layer-by-layer classification of the shape of root canals includes the following stages: remove layer-by-layer cone-beam computed tomography for the teeth of the upper and lower jaw; take pictures, analyze pictures in the coronal plane; determine the shape of the canals at the level of the mouth of the canal, at the level of the middle third of the canal and at the level of the apical third of the canal; refer the shape of the canals for each layer to a specific type and prescribe treatment depending on the type of geometric shape of the canal section, defined as type 1 - unchanging shape of the canal from the mouth to the apex, type 2 - changing shape of the canal from oval to round in the apical third, 3 type - changing shape of the canal from oval to slit in the middle and apical third, type 4 - changing slit shape of the canal in the middle and apical third, type 5 - changing shape of the canal from slit to oval in the apical third.

The variability of the shape of the root canal is important to understand for performing the stage of endodontic treatment - mechanical treatment (preparation of the root canal). The choice of the instrument and technique for canal preparation will determine the effectiveness and correctness of this stage, and hence the favorable prognosis of treatment.

Type 1 canals can be treated with one type of instrument, since it does not change the shape of the canal cross-section at the level of the orifice, middle third and apical third of the root. For example, root canals of a round or oval shape, after preparation with a hand or machine tool in the form of a drill, retain their shape close to the original. The shape of the drill during processing allows it to touch all the walls of the channel.

Canals with a changing shape of the root canal Type 2, type 3 and type 4 differ in the level of change in the shape of the cross-section: change in the shape at the level of the apex (type 2), change in the shape of the canal at the level of the middle third of the canal (type 3) and change in the shape at the level of the middle third and apex (type 4). Canals with a changing root canal shape require a different approach to the protocol of mechanical and drug treatment. The shape of the hand and machine instrument (drill, preparation file) assumes that the instrument during preparation will process (prepare) that part of the canal that is closest to the round shape. An appropriately sized instrument and a root canal preparation technique will only reshape the root canal in the part where the canal shape approaches the shape of the instrument. In the part of the canal where the instrument will not touch the root walls (if the shape is not round (oval or slit), it will be necessary to change the size of the instrument for preparation, the technique of preparation (machine or manual), or supplement it with medication of the root canal.

The invention is illustrated by tables, diagrams and drawings.

FIG. 1: Wein's classification of root canal configurations (1969)

FIG. 2: Classification of root canal configurations by Vertucci (1984)

FIG. 3: Classification of the shape of root canals by Kim (2001)

FIG. 4: Unchanging shape of the canals of the anterior teeth of the upper jaw

FIG. 5: Unchanging shape of the canals of the anterior teeth of the lower jaw

FIG. 6: Changing canal shape of the maxillary premolar

FIG. 7: Changing canal shape of the mandibular premolar

FIG. 8: Unchanging canal shape (palatine canal), changing canal shape (mesial buccal canal)

FIG. 9: Unchanging canal shape (mesial canal), changing canal shape (distal canal)

FIG. 10: Layer-by-layer classification of the cross-sectional shape of ducts

Table. 1. Layer-by-layer classification of the cross-sectional shape of channels

Table. 2. Layer-by-layer classification 4 types of cross-sectional shapes of channels

The invention can be illustrated by the following examples: Example 1: a patient takes a cone-beam computed tomography image, the image is analyzed in the coronal plane; The shape of the canals was determined at the level of the canal orifice, at the level of the middle third of the canal and at the level of the apical third of the canal, and the results showed that the shape of the canal of the incisors is rounded throughout the canal and does not change significantly with age. The canines of the upper jaw are characterized by an oval cross-sectional shape of the canal, which remains throughout the entire length of the canal. The frontal group of the teeth of the lower jaw is characterized by an oval shape of the canal (since the root has an oval shape, elongated in the vestibulo-oral direction), which does not change throughout the canal. Only 1.5% of cases of type 1 slit form according to Kim et al. in the older age group they are "rounded" in the apex area. The canines of the lower jaw of two root canines are characterized by a rounded shape of the canal in 0.2% of cases (revealing two root structures of the tooth). Thus, the group of anterior teeth of the upper and lower jaw can be characterized as a group with a non-changing canal shape (round or oval) (see Fig. 4, see Fig. 5).

Example 2: the patient takes a Cone Beam Computed Tomography image, the image is analyzed in the coronal plane; The shape of the canals was determined at the level of the canal orifice, at the level of the middle third of the canal and at the level of the apical third of the canal, and the results showed that the shape of the canals of the two-root maxillary premolars is characterized by a rounded shape in each root, which does not change from the mouth to the apex. The shape of the canals of single-rooted premolars of the upper jaw can vary from oval to slit-like or from oval to round in the region of the middle and apical third of the canal (see Fig. 6).

Example 3: a patient takes a Cone Beam Computed Tomography image, the image is analyzed in the coronal plane; the shape of the canals was determined at the level of the canal orifice, at the level of the middle third of the canal and at the level of the apical third of the canal, and the results showed that the shape of the canals of the mandibular premolars is oval and can vary from oval to slit-like or from oval to round in the region of the middle and apical third of the canal (see Fig. 7).

Example 4: a patient takes a Cone Beam Computed Tomography image, the image is analyzed in the coronal plane; The shape of the canals was determined at the level of the canal orifice, at the level of the middle third of the canal and at the level of the apical third of the canal, and the results showed that the shape of the canals of the upper molars in the palatine and buccal-distal roots is characterized by a round shape that does not change throughout. And the mesial buccal root of the first, second and third molars has a variable shape structure: from oval and slit-like to round, and the change in the shape of the canal occurs in the apical third, while the shape does not change in the mouth and middle part of the canal. (Only the second molar in the elderly age group showed an unchanging shape throughout the canal) (see Fig. 8).

Example 5: a patient takes a Cone Beam Computed Tomography image, the image is analyzed in the coronal plane; The shape of the canals was determined at the level of the canal orifice, at the level of the middle third of the canal and at the level of the apical third of the canal, and the results showed that the lower molars are characterized by variability in the shape of the cross-section of the root canals for both the distal and mesial roots. The shape of the channel cross-section changes more often in the young and middle age group. For the elderly age group, the most characteristic is the unchanging shape of the canals both in the mesial and in the distal root (see Fig. 10).

The cross-sectional shape of the channel can be divided into two groups: channels with an unchanging (constant) shape and channels with a changing shape. In turn, in canals with a changing shape, the change can be recorded in the median third or apical third of the canal (Tables 1 and 2). Thus, the correlation of the canal shape in Fig. 10 and the description in Table 2 allows us to say that a new system of layer-by-layer classification of the root canal shape has been developed.

Claims (1)

The method of layer-by-layer classification of the shape of root canals includes the following stages: remove layer-by-layer cone-beam computed tomography for the teeth of the upper and lower jaw; take pictures, analyze pictures in the coronal plane; determine the shape of the canals at the level of the mouth of the canal, at the level of the middle third of the canal and at the level of the apical third of the canal; refer the shape of the canals for each layer to a specific type and prescribe treatment depending on the type of geometric shape of the canal section, defined as type 1 - unchanging shape of the canal from the mouth to the apex, type 2 - changing shape of the canal from oval to round in the apical third, 3 type - a changing shape of the canal from oval to slit in the middle and apical third, type 4 - changing slit shape of the canal in the middle and apical third, type 5 - changing shape of the canal from slit to oval in the apical third.

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