Teeth, root canals, topography, access, how many canals are in the tooth. About the treatment of pulpitis of three-channel teeth and the prices for this procedure

Many people often ask the question - how many roots does a molar have? This issue is relevant for most doctors. Because the complexity of many medical procedures depends on the number of roots, ranging from treatment, restoration and ending with removal. After birth, each person begins to grow milk teeth from about 8 months, which should have 20 pieces by the age of 3. Then, after 6-7 years, dairy units are replaced by indigenous ones, which should already increase by almost 1.5 times - 32. At the same time, dairy ones can have only one root, but indigenous ones grow with several roots.

Often the root is located in the area under the gums, below the surface of the neck and its size is about 70% of the total volume of the organ. The number of chewing organs and the roots present in them is not the same. In dentistry, there is a special system by which the number of roots is determined, for example, at the sixth unit at the top or a wisdom tooth.

This image shows the side of the upper and lower dentition, which shows the number of roots that each tooth has.

So how many roots do adults have? This indicator is different for each person, it depends on various reasons - on heredity, on size, on location, on age and race of a person. For example, representatives of the Mongoloid and Negroid races have one more roots than representatives of the Caucasian race, and they also grow together quite often.

Attention! For ease of identification in dentistry, each tooth has a specific number. This system involves numbering according to the following principle - the jaw of each person is visually dissected in the center vertically, while the incisors go to the left and right, from which the count is taken. From the region of the central incisors, numbering is made to the ears.

• Units No. 1 and No. 2 are called incisors, under No. 3 - fangs, and under No. 4 and No. 5 small molars are indicated. They grow at the top and bottom. Usually, they all have one base, which has the form of a cone;
• The organs of the row numbered No. 6-7, No. 8, which are located on top, are called large molars and a wisdom tooth. They usually have three bases. These same units, which are below, have two roots, except for the wisdom tooth. It may have three, and sometimes four bases.

This system applies to adults. But as for children's milk teeth, their root system has some differences. Many people think that dairy plants do not have bases, and they grow without them, but this is not so. Usually the first teeth appear already from the root system, each unit usually has one base, which completely dissolves at the time of loss. Therefore, many believe that they do not exist at all.

How many channels

Important! It should be taken into account that the number of channels does not correspond to the number of root bases. In the place of incisors there may be two or three, but there may be one, which is divided into several. However, each person has a different number of indentations. For this reason, the doctor usually takes an X-ray examination to determine the exact definition.

There are no requirements for the number of recesses in dentistry, they are usually determined according to a percentage.

The root canal system is the anatomical space within the root of a tooth. It consists of a space at the crown connected to one or more main canals at the root of the tooth.

Features of the number of channels:

1. There may be some differences between the upper and lower organs. Usually in the region of the incisors and canines of the upper jaw, there is one channel;
2. The central bottom rows can have two recesses. But almost 70% have only one, and already in the remaining 30% - two;
3. In the region of the second incisor of the lower jaw, in almost 50% of cases, adults have two canals, in 6% of situations the canine has only one recess, and in the rest it has similar properties to the second incisor;
4. Dental unit number 4, which is also called the premolar, which is at the top, has three depressions. But a three-channel fourth premolar occurs only in 6% of cases, in the rest it has one or two depressions;
5. A similar fourth premolar, which is located below, has no more than two, but in most cases there is only one;
6. The upper fifth premolar can have a different number of recesses. In 1% of cases, there are units with three channels, in 24% - two, and in other cases there is one recess;
7. The lower fifth premolar meets one canal;
8. The sixth upper organ has the same ratio of depressions - three or four;
9. From below, sixes are sometimes found with two channels, in almost 60% of cases with three, they can also be with four;
10. The upper and lower seventh tooth has three canals in 70% of cases, and 4 in 30% of cases.

How many canals does a wisdom tooth have?

How many can a wisdom tooth have? This is a difficult question, because this organ has a very unusual structure. If it is located at the top, then it can have four, and sometimes even five channels. If this tooth is in the bottom row, then usually it has no more than 3 recesses.
In most cases, during eruption and already at the moment of full growth, the figure eight delivers unpleasant sensations and severe discomfort. To clean it, it is recommended to use a special brush, which is designed for hard-to-reach places. Typically, a wisdom tooth has narrow recesses that have irregular shapes. This property causes severe difficulties in performing medical procedures. Often, when improper eruption or other pathological processes occur, the complete removal of the figure eight is performed.

The wisdom tooth is the last to erupt, as if it is fighting for a place in the jaw, often shifting the dentition and bringing discomfort. The roots of the tooth have a swirling, intertwined shape, therefore, the canals of the tooth may not always be treatable.

What is the nerve for?

Attention! In addition to roots and canals, each tooth has a nerve. Typically, nerve fibers cover the region of the channels, while the nerves are grouped into branches. Each base of the unit has a nerve branch, and often there are several branches at the same time, while in the upper part the branch is divided.

Most of the oral cavity is occupied by organs whose main function is chewing and grinding food into smaller pieces. This contributes to its full digestion and better absorption of nutrients. A tooth is an organ that has a characteristic shape and consists of several parts. The outer visible part is called the crown in dentistry, the inner part is called the root. The element connecting the crown and the root is the neck.

An interesting fact is that, unlike a crown, a tooth may have more than one root. How many roots a tooth has, as a rule, depends on the location and purpose of the organ. In addition, the hereditary factor affects its structure and the number of roots. Finally, the situation can be clarified only with the help of an x-ray.

The article provides detailed information on how many roots the frontal, lateral chewing teeth, as well as the figure eight, or the so-called. In addition, you will be able to find out what is the purpose of the tooth root, why chewing units need nerves. The advice of dentists given in the following material will help prevent the development of dental diseases.

The tooth root is located in the inner part of the gum. This invisible part makes up about 70% of the entire organ. An unequivocal answer to the question: how many roots a particular organ does not have, since their number is individual for each individual patient.

Factors affecting the number of roots include:

1. organ location;
2. the degree of load on it, functional features (chewing, frontal);
3. heredity;
4. patient's age;
5. race.

Additional Information! The root system of representatives of the Negroid and Mongoloid races is somewhat different from the European one, it is more branched than, in fact, more roots and channels are justified.

Dentists have developed a special system of numbering teeth, thanks to which it is almost impossible for even a non-specialist to get confused in the units of the upper and lower dentition. To understand the principle of numbering, it is necessary to mentally divide the skull in half vertically. The first are the incisors - the frontal units of the upper and lower rows on the right and left. There are two of them on each side: central (No. 1) and side (No. 2). Further, fangs or so-called triplets follow. Four (#4) and five (#5) are the first and second premolars. And also these teeth are called small molars. All of the above units are united by the fact that they have only one "back" of a cone-shaped shape in both the upper and lower rows.

The situation is somewhat different with the first, second and third, we are talking about tooth number 6, 7 and 8. The upper six and seven (large molars) are endowed with three roots, however, in the wisdom tooth located on top, as a rule, there are also 3 bases . In the sixth tooth and in the 7th lower row, there is usually one root less than in the upper counterparts. The exception is the bottom eight, in this tooth there may even be not three, but four roots. This feature should be taken into account during the treatment of a four-canal tooth.

Additional Information! Many people mistakenly believe that their children's temporary milk teeth do not have "roots". This is absolutely not true. There are reasons, and their number can reach up to three, with their help, the chewing organs of babies are attached to the jaw. By the time the milk units are changed to permanent "roots", they disappear, as a result of which the parents have the opinion that they did not exist at all.

How many canals are in the teeth

Immediately it should be noted that the number of channels does not have to correspond to the number of roots. These concepts are not identical. It is possible to determine exactly how many channels in a tooth using an x-ray.

So, the upper incisors, as a rule, are endowed with two or three channels, in some cases it may be one, but branched in two. It all depends on the characteristics of the root system and genetic predisposition. The lower central incisors are predominantly single-channel, in 70% of cases, the remaining 30% have two recesses.

Lower lateral incisors in most cases, they are endowed with 2 channels, however, like the lower fangs. Only in rare cases canines located on the lower jaw are two-channel (5-6%).

The distribution of recesses in the remaining units of the dentition is carried out according to the following scheme, from which you can find out how many canals each tooth has:

• upper first premolar - 1 (9% of cases), 2 (85%), 3 (6%);
• bottom four - 1, less often 2;
• upper second premolar (No. 5) - 1 (75% of cases), 2 (24%), 3 (1%);
• the lower 5 is predominantly single-channel;
• upper first molar - 3 or 4;
• the lower first molar - 3 (60% of cases), less often - 2, extremely rarely - 4;
• top and bottom seven - 3 (70%), 4 - in other cases.

How many channels does a wisdom tooth have

Eight or the so-called third molar is somewhat different from other units of the dentition. To begin with, it should be noted that not all people have it, which is associated with genetic factors.

This organ, in addition to its inconvenient location, which causes discomfort during, has other differences. So, the upper third molar is the only unit, the number of channels of which can reach 5. It is worth noting that this is extremely rare, basically, a three- or four-channel wisdom tooth. The bottom eight has no more than 3 recesses.

Eight is often the cause of the development of dental pathologies. For example, the incorrect position of the third molar can contribute to the disruption of the growth of neighboring units. In such cases, it needs to be removed. If the figure eight does not bother and does not hurt, it is not necessary to pull it out. The indication for removal is only the presence of pain and the negative impact of the third molar on other units of the row.

So that there are no problems with the eight, dentists advise adhering to the following oral care rules:

• due to the inconvenient location of the figure eight, it is necessary to use a special brush;
• owners of the third molar should visit the dentist for a routine examination at least 2 times a year.

Why does a tooth have a nerve

A feature of the recess in the tooth is the presence of branched nerve endings in it, grouped into branches. The number of nerve endings directly depends on the number of roots and canals.

Purpose of dental nerves:

1. influence the development and growth of dental units;
2. thanks to the nerves, the organ is sensitive to external influences;
3. the dental nerve makes the chewing organ not just a bone, but a living unit of the oral cavity.

To prevent the development of dental pathologies is possible only if you follow the advice of qualified doctors and follow the rules of oral hygiene.

• do not abuse the rules of hygiene, brush your teeth only in the evening and in the morning. More frequent exposure to tooth enamel contributes to its erasure;
• hygiene procedures should be carried out half an hour after eating;
• use rinses to destroy the microbes remaining in the mouth after brushing;
• cleaning should be carried out for at least 3 minutes, performing circular movements.

Main Rule- in case of detection of the first signs of the disease, you should immediately consult a dentist. This will help prevent further development of pathology and save teeth.

Video: tooth anatomy

The contours of the intradental cavities are similar in these teeth. The central incisors are large, averaging 23 mm in length (span 18-29 mm). The lateral incisors are shorter - 21 - 22 mm (span 17-29 mm). The shape of the canals is usually type I and extremely rarely in these teeth, more than one root or more than one canal. If abnormalities exist, they are usually in the lateral teeth, and may present as an additional root (dens invaginatus), doubling, or fusion of roots (Shafer et al., 1963).

The pulp chamber on the vestibulo-oral incision narrows towards the cutting edge and expands at the level of the neck. Mediodistal pulp chambers of these teeth follow the contours of their crowns and the widest space at the cutting edge. The central incisors in young patients usually have three pulp horns. Lateral incisors usually have two horns and the contours of the intradental chamber tend to be more rounded than in the central incisors.

Upper first incisor

The dotted line indicates the contours of access to the intradental cavity. Gray color indicates the contours of the intradental cavity at a young age, black - in the elderly. Two sections of the root are shown:

1 - 3 mm from the apex,

2 - at the level of the mouth of the channel. (According to Harty).

In the vestibulo-oral projection, the channels are much wider than in the mediodistal one, and often have a narrowing just below the level of the neck of the tooth. Usually textbooks indicate that the coronal cavity in these teeth goes directly into the root canals. However, this narrowing is largely reminiscent of the orifices in multi-rooted teeth. This narrowing, as a rule, is not visible on the radiograph, but this should be taken into account when instrumenting the canals (it is better to open with a ball bur at low speeds).

The canals of the upper incisors taper towards the apex and are initially oval or irregular in shape at the neck, which gradually becomes round towards the apex.

There is usually very little apical curvature in the central incisors to the distal or labial side. The apical part of the lateral incisor is more often curved, usually in the distal direction.

Upper second incisor

The frequency of occurrence of lateral (lateral) canals in the central incisors is 24%, in the lateral ones - 26%, and the frequency of deltoid ramifications (additional canals) in the central incisors is about 1%, in the lateral ones - 3%.

The apical opening in the central incisors in 80% of cases is located at a distance of 0-1 mm from the radiographically determined root apex, in 20% of cases - 1-2 mm. In lateral incisors, in 90% of cases, these ratios are from 0 to 1 mm, in 10% - from 1 to 2 mm. With age, the anatomy of the intradental pulp changes due to the deposition of secondary dentin, and the roof of the pulp chamber may be at the level of the neck, although in young teeth the roof of the pulp chamber reaches 1/3 of the length of the clinical crown of the incisors. Significant narrowing can be seen on radiograph mediodistally. However, it must be remembered that the canal is wider in the labial-palatal direction, so it can often be relatively easily passed, although it looks very thin or not visible on the radiograph.

Upper fang

It is the longest tooth in the mouth, averaging 26.5 mm (range 20-38 mm). It is extremely rare to have more than one root canal. The pulp chamber is comparatively narrow and has only one horn, and is much wider on the vestibulo-oral section than on the mediodistal section. The root canal is type I and acquires a round shape only in the apical third. The apical constriction is not as pronounced as in the incisors. This fact and the fact that often the apical part of the root is significantly narrowed, with the result that the canal becomes very narrow at the apex, makes it difficult to determine the length of the canal.

Upper fang

The canal is usually straight, but sometimes at the apex it curves distally (in 32% of cases) and, less often, laterally. Vestibular deviation of the canal was registered in 13% of cases. The frequency of occurrence of lateral (lateral) canals is about 30%, and additional apical canals - 3%. The apical opening is located in 70% of cases in the range from 0 to 1 mm in relation to the root apex, and in 30% - in the range of 1 - 2 mm.

Access to the canals of the upper incisors and canines

Access may vary in size and shape depending on the size of the pulp chamber. It should be such that the instruments can reach the apical constriction without bending or being obstructed by the canal walls.

If the access is too close to the cingulum, this will lead to significant bending of the instruments and possible perforation or steps.

An incorrectly formed access cavity in incisors and canines leads to the formation of a ledge on the labile surface of the canal due to a sharp curvature of the instrument in the canal. Such access leads to non-removal of pulp residues.

Ideally, the access should be close enough to the incisal edge to allow for unhindered entry of the instruments up to the apex. Sometimes the cutting edge and the labial surface of the tooth are involved in the access (see Fig.). At first glance, this is contraindicated in terms of aesthetics. However, if the root canal is not fully treated, then this will not ensure the long-term health of periodontal tissues.

Access to the upper incisors: a) view from the side of the sky; b) side view.

On the other hand, modern bleaching and restorative techniques make it possible to provide aesthetics, strength and other requirements in the restoration of these defects.

Since the pulp chamber is wider at the incisal edge than at the neck, the access contour must be triangular and sufficiently extended medially and distally to include pulp horns. With proper access, it is necessary to widen the cervical constriction for adequate instrumentation of the canal.

Access contours in incisors:

a) correct access contours in incisors and canines; b) the dotted line shows an incorrect access contour in which the infected material can remain in the pulp chamber and be pushed into the canal during its further instrumental processing. (by Harty)

Proper access is especially important in older patients, as a narrowed canal requires thinner instruments that can bend sharply or even break. In such patients, it is better to immediately make access closer to the cutting edge than usual, since due to the narrowing of the pulp chamber, a straight line of transition of this chamber into the canal is formed. This will ensure the effectiveness of the preparation.

Access contours in the upper canine.

Upper first premolar

Upper first premolar with two roots

Usually these teeth have two roots and two canals. The frequency of occurrence of a variant with one root, according to the literature, is from 31.5% to 39.5%.

These data show the ratio for people of Caucasian origin. In Mongoloids, the frequency of these teeth with a single root exceeds 60% (Walker, 1988). One study (Carns and Skidmore, 1973) found 6% of teeth with three roots. Typically Caucasoid tooth - with two well-developed roots, which are separated in the middle third of the root. In Mongoloids, fusion of roots prevails.

Possible morphology of the roots of the upper first premolar in transverse sections

This tooth usually has two canals and, in the case of a single-rooted variant, these canals may merge and open with a single apical foramen. Many types of canal configurations and the presence of lateral canals were found in these teeth, especially in the apical region - 49.5% (Vertucci and Geganff, 1979). The three-root variant has three canals: two buccal and one palatal.

Typically, the average tooth length is 21 mm, which is shorter than that of the second premolar. The pulp chamber is wider in the buccal-palatal direction with two clearly distinguishable horns. The bottom of the chamber is rounded, with the highest point in the center and usually just below the level of the neck. The mouths of the canals are funnel-shaped.

With age, the size of the pulp chamber is mainly reduced due to the deposition of secondary dentin on the roof of the pulp chamber, which leads to the fact that the roof of the cavity becomes closer to the bottom. The bottom remains below the level of the neck, and the roof, due to the deposition of dentin, may also be below the level of the neck.

The canals are usually separated and very rarely merge, taking on a ribbon-like shape characteristic of the second premolar. They are usually straight and round in cross section.

Upper second premolar

Upper second premolar.(I channel configuration type).

This tooth tends to be single-rooted. Type I of the canal configuration prevails, however, in 25% there are types II and III, and in 25% there may be types IV-VII with two apical openings.

Thus, the main type of this tooth can be considered as single-rooted with one canal. Infrequently, there may be two roots, and then the tooth resembles a first premolar with the cavity floor located well below the neck of the tooth. The average length is slightly longer than the length of the first premolar and averages 21.5 mm.

The pulp chamber is expanded in the buccal-palatine direction and has two pronounced horns. Compared to the first premolar, the bottom of the chamber is located closer to the apex.

The root canal is wider in the buccal-palatal direction and narrower in the mediodistal direction. It tapers towards the apex, rarely round in cross section, except for 2 or 3 mm at the apex. Often the root of this single root tooth is divided by a groove into two sections in the middle third of the root. These sections join almost invariably and form a common canal with a relatively large apical foramen. The canal is usually straight, but the apex may have a distal and, less frequently, buccal curvature.

With age, the displacement of the roof of the pulp chamber is the same as in the first premolar.

Access in upper premolars

Access in the upper premolars is always through the chewing surface. The access shape is oval, elongated in the buccal-palatal direction. In the first premolars, the orifices of the canals are visible just below the level of the neck. The second premolar has a canal in the form of a ribbon, the mouth is located significantly below the neck of the tooth.

Since the horns of the pulp chamber are well defined, they are easily exposed during preparation and can be mistaken for the orifices of the canals.

Upper first molar

Access contours to the upper premolars.

This tooth usually has three roots and four root canals. Additionally, the canal is located in the medio-buccal root. The shape of the channel system has been studied both in vivo and in vitro. In in vitro studies, an additional channel was found in 55 - 69% of cases. The canal configuration is usually type II, but type IV is present with two separate apical foramina in more than 48.5% of cases. In in vivo studies, an additional second channel was found less frequently and had difficulty in finding it. It was found in 18 - 33% of cases.

Upper first molar.

The palatine and distal roots usually contain a type I canal. In Caucasians, this tooth is about 22 mm long, the palatal root is slightly longer than the buccal ones. In the teeth of the Mongoloids, there is a tendency to closer and denser arrangement of the roots and the average length of the tooth is slightly less.

The pulp chamber is quadrangular in shape and wider bucopalatine than mediodistal. It has four pulp horns, of which the medio-buccal horn is the longest and sharpest in outline, and the disto-buccal horn is smaller than the medio-buccal horn, but larger than the two palatine ones. The bottom of the pulp chamber is usually located below the level of the neck and is rounded with a convexity to the occlusal surface. The mouths of the main canals are funnel-shaped and lie in the center of the roots. The lesser medio-buccal canal, if present, lies on the line joining the orifices of the medio-buccal and palatine canals. If this line is divided into three parts, then the mouth of the additional canal will lie near the first third, closer to the mesio-buccal main canal.

It must be remembered that the shape of the incisions in the neck area and at the level of the middle of the crown of the pulp chamber of various configurations (the shape of the incision in the neck area is more diamond-shaped than quadrangular). In this regard, the mouth of the medio-buccal canal is closer to the buccal wall than the mouth of the distal canal to the distal. Therefore, the distal-buccal root, and hence the mouth of its canal, is closer to the middle of the tooth than the distal wall of the chamber. The mouth of the palatal canal is usually easy to find.

Significant variations are observed in cross sections. The medio-buccal canals are usually the most difficult to instrument because they run medially. The lesser medio-buccal canal is often very narrow and tortuous and joins with the main canal. Since both mesio-buccal canals lie in the buccal-palatal plane, they often overlap each other on x-rays. Additional difficulties are encountered in connection with the frequent curvature of the mesio-buccal root in the distal direction in the apical third of the root.

The distobuccal canal is the shortest and often narrowest of the three canals and branches off the chamber distally, it is oval in shape and then becomes round towards the apex. The canal usually curves medially in the apical half of the root.

The palatine canal is the largest and longest of all three main canals and has a round shape throughout its section, tapering to the apex.

About 50% of the palatine roots are not straight, but curve towards the buccal side in the apical part (4-5 mm from the apex). This curvature is not visible on the x-ray.

With age, the canals become narrower and their mouths more difficult to find. Secondary dentin is deposited mainly on the roof of the pulp chamber and, to a lesser extent, on the bottom and walls. As a result, the pulp chamber becomes very narrow between the roof and the bottom. This can lead to perforation of the furcation, especially when using a turbine handpiece, if the operator does not notice the narrow chamber. To prevent this complication, it is advisable to limit the use of the turbine handpiece to the preparation of enamel and, partially, dentin, and complete the formation of access at low speeds. You can estimate the distance between the hillock and the roof of the chamber on the radiograph. This distance is marked on the drill and serves as a guide.

Relatively recent clinical observations highlight variations in the anatomy of the canals of these teeth. There are reports of teeth with two palatal canals.

Upper second molar

Upper second molar.

Usually this tooth is a small replica of the first molar, however, the roots usually diverge less and more often there is a fusion of the two roots. The form with three canals and three apical foramina prevails, the average length is 21 mm.

Root fusion is found in 45-55% of Caucasians, and Mongoloids in 65 to 85% of cases. In these cases, usually the mouths of the channels and they themselves are located closer to each other or merge.

Access contours in the upper molar.

Upper third molar

The upper third molar shows great variability. It may have three separate roots, but more often there is a partial or complete fusion of the roots. Traditional endodontics, access and instrumentation can be very difficult.

Access to the cavity of the upper molars

Access contours are usually in the medial 2/3 of the occlusal surface in the form of a triangle with a base to the buccal surface and an angle to the palatine. Due to the location of the distal buccal canal further from the buccal surface, there is no need for extensive tissue removal at this location.

Lower central and lateral incisors

Lower first incisor. (I channel configuration type).

Both teeth have an average length of 21 mm, although the central incisor is slightly shorter than the lateral incisor. The morphology of the dental canals can have one of three configurations.

Lower second incisor. (IV channel configuration type).

Type I- one main canal from the pulp chamber to the apical foramen.

Type II / III- two main canals that merge in the middle or apical third into one canal with one apical foramen.

Type IV- the two main canals remain separate for the entire length of the root and with two apical foramina.

All studies show that type I is the most predominant. Two channels are registered in 41.4% of cases, and type IV - in 5.5% of cases.

There is evidence that two canals are less common in Mongoloids in these teeth.

The pulp chamber is a small replica of the upper incisors. There are three pulp horns, not very well defined, and the chamber is wider in the labial-lingual direction. In the single-channel variant, it can be bent distally and, more rarely, labially. The canal begins to narrow in the middle third of the root and becomes round. With age, the changes are the same as in the upper incisors and the pulp chamber may be located below the level of the neck of the tooth.

lower fang

Lower canine.

This tooth resembles an upper canine, although it is smaller. Very rarely it has two roots. Its average length is 22.5 mm. The most prevalent type I canal, however, the main deviation in the canines is the variant with two channels (frequency about 14%). In less than 6% of cases, it finds a type IV canal configuration with two separate apical foramina.

Access in lower incisors and canines

Essentially, the access is identical to that of the upper teeth. However, with severe lingual curvature of the incisor crowns and due to very thin (especially in the elderly) canals, it is sometimes necessary to involve the incisal edge, and sometimes the labial surface of the tooth, to avoid bending the instrument.

Access contours in the lower canine are shown in fig.

Access contours in the lower incisors.

Access contours in the lower canine.

lower premolars

These teeth are usually single-rooted, however sometimes the first premolar may have a bifurcation of the root in the apical half.

Type I channel prevails. Where there are two canals (usually in the first premolar), there may be IV/V types of configurations. Types II/III occur in less than 5% of cases. The highest occurrence of two canals in the second premolar is reported at 10.8% (Zillich and Dowson, 1973).

One report stated that two canals in the first premolar were three times more common in African Americans than in whites (Trope et al., 1986). More often this option is found among the southern Chinese. In less than 2%, three canals may be present in the first premolar.

The pulp chamber of the lower premolars is wider in the bucco-lingual direction than in the mediodistal direction, and has two horns, the buccal one is better developed. The lingual horn is small in the first and larger in the second premolar.

Lower first premolar. (II type of channel configuration). (According to Harty).

The canals of the lower premolars are similar to those of the canine, although they are smaller, but they are also wider in the buccolingual direction until the middle third of the root, when they narrow and become either rounded or bifurcated.

Lower second premolar. (I channel configuration type). (According to Harty).

Access in lower premolars

Access in the lower premolars is essentially the same as in the upper premolars, through the masticatory surface.

In the two-canal variants, the first premolar may need to expand the access to the labile surface for unobstructed access to the canals.

Access contours in lower premolars.

lower first molar

Usually this tooth has two roots, medial and distal. The latter is smaller and usually rounder than the medial one. Mongoloids have a variant with an additional distal-lingual root with a frequency of 6 to 43.6% (Walker, 1988).

Lower first molar. (According to Harty).

This two-rooted tooth usually has three canals, the average length of the tooth is 21 mm. Two channels are located in the medial root. In 40-45% of cases, there is only one apical foramen in the medial root. The single distal canal is usually larger and more oval than the medial canals and in 60% of cases opens on the distal surface of the root close to the anatomical apex.

The attention of specialists was attracted by the work of Skidmore and Bjorndal (1971), who showed that there are two channels in the distal canal in more than 25% of cases. In Mongoloids, due to the tendency to double the distal root, the frequency of occurrence of two canals in this root is even higher - about half (Walker, 1988).

There have been case reports with five channels.

Lower first molar with five canals. (According to Harty).

The pulp chamber is wider at the medial than at the distal wall and has five pulp horns. Lingual horns are higher and pointed. The bottom is rounded with a convexity to the chewing surface and lies immediately below the level of the neck. The orifices of the canals are funnel-shaped, and the medial canals are narrower than the distal canals.

Of the two medial canals, medio-buccal and medio-lingual, the first of these is the most difficult to pass due to its tortuosity. It leaves the pulp chamber in a medial direction, which changes to distal in the middle third of the root. The melolingual canal is slightly wider and usually straight, although it may curve medially in the apical third of the root. These two channels may have a dense network of anastomoses between them along their entire length.

When there is an additional distal canal, it is located more lingually and tends to curve to the buccal side.

With age, the deposition of dentin comes from the side of the roof, and the channels narrow.

Lower second molar

In Caucasians, the second molar resembles a small version of the first, with an average length of 20 mm. There are two channels in the medial root, and only one in the distal one. The medial canals tend to merge in the apical third and form a single apical foramen.

Lower second molar. (According to Harty).

Studies conducted in 1988 showed a high tendency for root fusion in Chinese (33-52% of cases). On a longitudinal section, such teeth resemble a horseshoe. Where there is incomplete separation of the roots, there may be an incomplete separation of the canals, which is accompanied by a dense network of anastomoses between the canals and can lead to unpredictable localization of the orifices. One of the localizations was called the middle buccal orifice with a middle buccal canal. In Caucasians, this anomaly is recorded in 8% of cases, which is significantly less than in the Chinese.

lower third molar

This tooth is often underdeveloped with numerous and poorly developed cusps. Usually there can be as many channels as there are tubercles. The root canals are relatively larger than those of other molars, possibly due to the late development of this tooth.

Despite these shortcomings, it is usually less difficult to fill the roots of a lower than an upper wisdom tooth, because access is usually easier due to the medial inclination of the tooth, and also because they more often follow normal anatomy, resembling a second molar, and are less likely to have deviations. from the norm.

Access in lower molars

Access contours in lower molars.

If there is a second distal canal in the first molar, a more quadrangular approach may be necessary. Care must be taken when removing the roof of the pulp chamber so as not to damage the bottom. To improve the visual control of the canal mouths, access can be extended. The access walls should diverge towards the chewing surface to resist chewing forces and prevent displacement of temporary fillings.

If the channel path is non-standard, access can be expanded and/or modified.

Thus, standard, universal, tabular methods for determining the working length of tooth canals cannot satisfy clinicians today. Of course, you need to have a more or less correct idea of ​​the possible deviations of the morphological features of the cavities, but the decisive factor is the X-ray examination with the introduction of files into the root canal. At the same time, it is desirable not to try to insert the instrument to its full working length, since it is almost impossible to obtain undistorted radiographs.

Dental canals are narrow cavities located inside the roots of teeth. Their number depends on the number of roots, but is not always equal to it.

Features of the structure of teeth, their roots and canals

There are no two identical root dental systems, which is explained by the purely individual structure of human teeth. In addition, the root system of incisors, canines and molars is arranged in accordance with their purpose:

• Ones and twos (cutters) are needed for biting off food.
• Fours and fives (premolars) perform the initial chewing function.
• Sixes and sevens completely grind food.

Based on this, it becomes clear that the seventh tooth needs more nutrients than the fifth. It must be strong and hardy, therefore it has a more developed channel system. Despite the fact that the 6th tooth in the lower jaw performs the same functions as the seventh, it usually has fewer canal passages. This is due to the fact that it is less chewing load.

For a detailed study of the structure of the dentoalveolar apparatus of a particular patient, an X-ray examination is used.

Each dental unit consists of:

• crowns - the area above the gum;
• necks - the area between the crown and the root;
• root - the area under the gum.

Inside the crown is the pulp, which passes into the root canals. At the end of the root there is a small apical opening through which blood vessels and nerve endings pass, starting from the main neurovascular bundle and ending in the pulp.

When a person’s pulp becomes inflamed, not only it, but also all root canals should be cleaned of infected tissues, since they are “communicating vessels”. If at least one canal is left uncleaned, pathogenic microorganisms will continue to develop inside the dental unit, which will lead to its removal. That is why the doctor must know the exact number of channels in the tooth.

How many nerves are in a human tooth

Thanks to the nerve, the tooth can respond to external stimuli. After removing the pulp and filling the canal passages, the dental unit loses sensitivity, as it loses the nerve. But due to the removal of blood vessels, problems begin with its blood supply and mineralization. The crown becomes less durable and more prone to various chips and breaks. The enamel quickly darkens, and it cannot be whitened with high quality even with strong chemical reagents.

Before removing the pulp, the patient is sent for an x-ray to find out how many channels are in the operated tooth: the dental nerve in a person in the tooth is one, and there can be several canals. Such preparation allows depulpation to be carried out competently and quickly.

Types of root canals

There are several options for the structure of dental canals:

• at the root there is one canal passage, which corresponds to one apical opening;
• there are several canal branches in the root, which are connected in the region of a single apical opening;
• two different branched passages have one mouth and two apical openings;
• canal cavities in one root merge and diverge several times;
• three root canal passages emerge from the same orifice, but have 3 different apical openings.

There can be as many channels as there are roots, but often their number is different. Several types of canals may be present in one molar and premolar.

How many canals in a person's teeth - table

Statistically, the number of channels depends on the depth of the tooth: the deeper it is located in the jaw, the more channels it has. This is due to the increased load on the molars located at the base of the dentition.

Usually the teeth of the upper jaw have more canals. But this pattern is not observed in all patients.

The table below shows the average statistical data on how many channels are in the human teeth from above and below.

The number of canals in the teeth in the lower jaw

The teeth on the lower and upper jaws are significantly different from each other. This is partly due to the not quite uniform load and different functions. There are usually fewer canals in the teeth in the lower jaw. But each specific case requires detailed study. Therefore, first the dentist sends the patient for an x-ray, and only then proceeds to open the crown and treat pulpitis.

It is impossible to start the treatment of caries and pulpitis, based only on encyclopedic information, because:

• 6 tooth of the lower jaw can have as many channels as you like - from 2 to 4;
• in the 5th tooth below there is usually only 1 canal, but in about 10% of patients there are fives with 2 canals;
• in the 4th tooth, there is usually only 1 canal, but in about a third of cases there are 2.

The eighth tooth on the lower jaw is the most "unpredictable". How many exactly channels in the wisdom tooth, located below, can only be determined using x-rays. Officially, there are no more than 3 of them, but during the treatment of caries, additional cavities usually open. It is because of the incomprehensible structure and inconvenient location that the figure eight is most often removed.

It is impossible to treat a dental unit without studying the structure of its root and canal systems. This can only aggravate the pathology and lead to complications.

The number of canals in the teeth in the upper jaw

The root system of the teeth of the upper jaw is more complex and branched. This explains the longer treatment of molars located at the top, and the frequency of repeated visits due to not completely sanitized dental cavities.

Features in the structure of the canal system of teeth in the upper jaw:

• The 6th tooth of the upper jaw is most often three-channel. But sometimes there are also four-channel first molars.
• The fourth and fifth tooth from above are most often two-channel, but single-channel and three-channel premolars are sometimes found.
• The 4th upper tooth usually has 2 canals, but sometimes there are premolars with 1 or 3 canals.

The “wise” figure eight on the upper jaw is a four-channel tooth. Extremely rare third molars with 5 canals. However, in dentistry, even cases of the presence of eight-channel wisdom teeth located at the top have been recorded.

Canals in milk teeth

There are as many nerves in milk teeth as there are in molars - one. In addition, temporary units are similar to permanent ones in terms of the structure of the root system. That is, such a milk tooth, as the upper six or second molar, has a canal system similar to its root counterpart, the second premolar.

Nerve endings perform standard functions:

• signal developing caries;
• responsible for the growth and development of teeth;
• control the flow of water and nutrients to dentin and enamel.

The root canals of milk teeth are also treated and sealed, but the tactics of their treatment depends on how long ago they erupted. Permanent units are formed under temporary ones, so treatment should be aimed at preserving them. Milk teeth can only be removed when the permanent teeth are ready to erupt.

The roots of permanent incisors, canines and molars are not formed immediately, but over a period of approximately 3 years. Treatment of permanent teeth with immature roots also differs from the standard. Canals in the teeth of patients four, five, six years old (depending on the rate of formation of the dentition) are filled with a special paste with calcium and fluorine, which helps to close the roots.

What diseases cause inflammation of the tooth canals

Root canals can become inflamed with the development of the following diseases:

• caries;
• pulpitis;
• periodontitis.

An accurate diagnosis for inflammation of the pulp and canals of the tooth can only be determined by the dentist after X-ray diagnostics and a visual examination of the oral cavity.

Root canal treatment

The scheme of treatment of dental canals consists of several stages:

1. First, access to the problem area is released: with the help of a special dental instrument, a filling or a section of the crown damaged by caries is removed.
2. Then the contents of the pulp are removed, and the canal passages are cleaned mechanically using antiseptic preparations.
3. After that, the root is prepared for filling. At this stage, the dentist can form the correct conical shape of the canal.
4. Then the channels are carefully sealed. If milk teeth are being treated, the dentist uses a special filling paste, which gradually dissolves as the root dissolves.
5. After that, a filling is placed on the crown.

The indicated treatment regimen is standard and does not depend on how many channels there are in the diseased tooth. The main thing is that all dental canals are cleaned, treated with an antiseptic and carefully closed. If the treatment is not correct, it may be necessary to remove the dental unit and visit the jaw surgeon.

Teeth are single-channel, two-channel, three-channel and even eight-channel. When one of the passages becomes inflamed, it is necessary to clean and seal not only it, but also all other channels, since the infection could penetrate into them.

What do you know about your teeth? The answers of the majority will be limited to what is on the “surface”: a description of their state of health, features of the shade of the enamel and its sensitivity. But even a dentist with great experience cannot tell you about the "inner world" of your teeth without diagnostic procedures with 100% accuracy. Many people learn about how many roots the teeth have only when they are removed. It is the same with canals: the fact that there are canals in the roots, how they are located and how many of them, most often becomes known only in the course of treatment. We will tell you a lot of interesting things about the roots and canals of teeth.

How is a tooth made?

A tooth consists of a crown, root and neck.

If you do not delve into the question, the structure of the teeth seems to be quite simple: an enameled crown is located above the gum, and roots are located under the gum. Each tooth has a certain number of "roots". It depends on the degree of load on him: the more it is, the more powerful his restraint system will be. Obviously, in chewing molars, the number of roots and canals of teeth will be greater than in representatives of the biting group.

Let's go a little deeper: the "spine" itself is covered with cement, and under it is dentin. The hole in which the root is located is called the alveolus. Between them there is a small space with connective tissue -. Here are the nerve fibers and blood vessels that feed the dental tissues.

Each tooth has a cavity inside. In it, under a reliable “shell”, there is a pulp - a bundle of nerves and blood vessels that provide nutrition to bone formations. The pulp is sometimes called the heart of the tooth - if it has to be removed, it becomes dead. The cavity narrows towards the roots - this is the dental canal. It stretches from the top of the "root" to its base. At the top of the tooth root there is a hole through which the nerves and vessels pass, connecting the pulp with the rest of the tissues of the jaw.

Number of roots in each tooth

Let's find out how many roots teeth have. If you draw a vertical line in the middle of the jaw, dividing it into the right and left parts, then the first from the line in both directions will be 2 incisors, then canines, then 2 small root premolars and 2 large molars, and the very last ones are “wise » eights.

Important: the shape of the channels may be irregular, they are narrow and ornate, they are characterized by branching and the formation of pockets. That is why bacteria, getting into them, feel at ease, and the filling process causes many difficulties.

Now you know the structural features of the teeth and will be able to fully imagine the procedure for their removal, because its complexity directly depends on the number and nature of root growth. Or if you are suddenly asked how many roots the 6th tooth has from below, even such an unexpected question will not confuse you.