Molars and premolars: main differences and features

Milk and molar teeth in children

Many people believe that there are no differences between permanent and temporary teeth, but this is not true. So, how to distinguish a baby tooth from a molar? At a minimum, their number differs (milk - 20, permanent, as a rule, 32). Temporary teeth have a light shade, while permanent teeth are naturally more yellow. Indigenous ones are also significantly larger in size than dairy ones - visually it is quite easy to distinguish them. Here are the most common questions asked by Internet users on this topic.

1. Do children have molars?
   Of course, there are, and at a certain point they begin to actively erupt.
2. How many molars do children have?
   From 28 to 32 (the maximum set appears after all eights appear).
3. Which molars appear first in a child?
   Typically, the lower central incisor erupts first.
4. At what age do children start to get their molars?
   Usually, dentition renewal begins after 6–7 years, but there are no strict limits.
5. Do children lose molars?
   By themselves - no, as a result of injuries and illnesses - yes.
6. What are the risks of removing a molar tooth in children?
   As corny as it may sound, his loss. And yes, a new one will not grow. Everything is like adults.
7. What to do if a child has yellow molars?
   Permanent teeth have a more yellowish tint than temporary teeth. Plaque on a child’s molars is normal, but hygiene should never be neglected.
8. What to do if a child has black molars?
   When teething, baby teeth may have a black color (the so-called Priestley plaque, or pigment bacteria). However, this does not happen with molars. If they are black, go to the dentist immediately.
9. What to do if a child does not have molar buds?
   This happens, but very rarely. Fortunately, with modern implantation and prosthetics technologies, the problem can be solved.
10. Is it normal for a child to have crooked molars?
    Contact an orthodontist immediately: correcting a bite in childhood is much easier and faster than in adults.
11. Which teeth do children replace with molars?
    All twenty, plus new molars appearing.

Formation of permanent teeth

Molars are formed from the epithelial dental plate. The appearance of their rudiments occurs only closer to the 5th month of fetal development inside the mother’s womb.

There are two groups of molars:

• Substitutes. This includes canines, incisors and premolars, which have temporary analogues.
• Additional. This group includes molars that do not have milk predecessors.

The growth of the primordial teeth of the replacement type occurs in the same alveolus as the temporary teeth; they are located behind the lingual surface of the primary teeth. Only after some time does the volume of bone tissue increase, ensuring their insulation.

Additional teeth are formed only after a year, since for this the jaw must reach the appropriate size.

Molars in children: symptoms of eruption

• Fever. When teething in children, body temperature may rise, usually not higher than 38 degrees.
• Itching and pain at the site where the molar appears. Various gels and ointments, as well as gum massage, will help relieve children from unpleasant sensations.
• Increased salivation and runny nose.

Important!

The growth of molars in children, especially at the initial stage, leads to weakened immunity. Take vitamins and do not forget about preventive visits to the dentist.

First signs

It is advisable to recognize the onset of teething in a child in time in order to be able to provide him with the necessary help. As a rule, symptoms of the upcoming appearance of the first tooth in a baby appear within a few days - in most children this period lasts up to several days and ends with the eruption of the outer shell of the gums.

Parents can recognize that their baby is starting to teethe by the following signs:

1. The appearance of sudden changes in the child’s behavior: sleep disturbance, irritability, crying, refusal to take the breast or pacifier;
2. The formation of increased salivation, often accompanied by the appearance of rashes around the baby’s mouth, chin, and chest due to excessive saliva;
3. At the site of tooth eruption, the gums swell and become swollen;
4. The child bites everything that gets into his hands, trying to relieve the irritating itching that appears in the gums.

When does a child's molars come out?

Most parents are interested in the question: at what age do children’s molars begin to erupt? The first buds form in the fifth month of pregnancy. The exact timing of their appearance has not been determined and depends on the individual characteristics of the organism. Nevertheless, an approximate scheme for the eruption of molars in children exists. If the appearance of a permanent tooth is delayed for more than six months from the extreme threshold (especially after the loss of a baby tooth), consult a specialist. The doctor will take control of the process and be able to identify complications.

Maxillary premolars

The crown of the premolars on the upper dentition has a prismatic shape. The buccal and palatal bones often have a convex surface. The first and second premolars in the row also have their differences.

First premolar

The difference between the first premolar of the upper jaw is the predominance of the vestibular surface over the palatal surface. Its contact surfaces are rectangular in shape. The buccal tubercle has two distinct slopes. The root of such a tooth often has a bifurcation.

Second premolar

In such a tooth, the buccal surface usually predominates over the palatal surface, which is more rounded. In most cases, this premolar tooth has a single cone-shaped root. However, there are also cases when it has a split.

Pattern of growth of molars in children

In most cases, the permanent tooth appears 3 to 5 months after the temporary tooth falls out. The order of eruption of molars is in many ways similar to the appearance of milk teeth. The first molars in children are the central lower incisors. The upper permanent teeth develop later than the lower ones, if we consider them in pairs.

Location and anatomical features of molars

Since man is an omnivore, for a healthy metabolism he needs different foods, including rough, animal, and plant foods. In order for the body to absorb it, you need to chew the food well, which is what molars do. Their chewing area reaches 1 cm2. Each such organ can withstand pressure of up to 70-75 kilograms. In total, there are up to 12 such units in the oral cavity of an adult. Six of them are located on the lower jaw, six on the upper jaw, three on each side.

The last elements in the series are the third molars. They are also called wisdom teeth. They cut through in adults, and often may not cut through at all. Their roots can have two, three or more branches. The size of the crowns of molar units can reach from 7 millimeters, in some organs up to nine. Their chewing surface is diamond-shaped with rounded corners. It has four tubercles, which are separated by 3 grooves located transversely. Classification of roots:

• palatal;
• buccal-distal;
• buccal-mesial;

The last type of roots is the largest. The palatine root belongs to the middle ones. The shortest in size is the buccal-distal. Each subsequent molar unit is endowed with smaller roots and a crown portion than the previous one. The first molar organs are large, their coronal surface is significant in area, and the size of the roots is the largest. The second units are already smaller in size. The extreme units do not have milk precursors. Their root length and crown size vary significantly. Usually, there are 3 tubercles on the crown, one of which is lingual and 2 buccal. As a rule, their roots are not too long, but they are often displaced and deviated to the side. Wise teeth can come into contact with 2 antagonists at the same time. This is considered normal.

On the upper jaw

The top row has its own characteristics and differences. Their main aspect is location. They form a straight line that is only slightly curved and diverges to the sides. The slope of the units increases from the first to the third segment. In addition, in the upper teeth:

1. Larger in size than the organs located in the lower jaw;
2. The root system is more powerful, it has three roots;
3. The tooth surface area is extensive;
4. Good ability to chop and chew food;
5. The outer side is covered with sharp tubercles with protruding forms, there are 3 or more of them;

The second molars of the upper row in the coronal part are similar to the first molar units, although they are more massive and rectangular. They are easier to dissect. The roots are usually grouped, sometimes merging with each other. The canals, which are parallel, often overlap each other when X-rays are taken. The roots are shorter compared to previous teeth. The three mouths often form a flat triangle, less often a straight line. The convex bottom of the chamber gives the mouths a funnel shape. It happens that the channels to the bottom of the chamber bend at a very acute angle.

Rarely do the upper posterior units have four roots. The first molar large organ of the upper jaw is equipped with more powerful roots than its lower antagonist. The peculiarity of the second molar teeth is that their crown can have any shape, while the lower ones can only have a certain shape. Properties of the shape of the upper units: cubic, regular, with a clear cross-shaped groove that divides the surface into four parts. The eights that are located on top are smaller in size than the bottom ones. In addition, they can develop from 1 to 4 or more roots.

On the lower jaw

Molars on the chewing side have tubercles, as well as fissures, that is, grooves. They can be shaped like cones, drops, or grooves. Reliefs are formed during the formation of organ rudiments. Since they grind food, there is a high risk of caries. To avoid such a pathology, it is necessary to seal the fissures. The procedure prevents food particles from getting into the grooves. In addition, sealants nourish the enamel layer with fluoride, helping it become healthier. To achieve maximum effectiveness, the session is carried out immediately when the units erupt, or within 12 months.

The molar organs of the lower row differ from the segments of the upper jaw. Their features:

• Such units have a different anatomical structure.
• They most often have 3 canals and 2 roots.
• They are smaller in size than their antagonists.
• The number of tubercles varies from three to six.
• The distal and medial roots are parallel.
• Root fusion is often diagnosed.
• The crown of the first unit has the shape of a cube, it is slightly elongated in the direction of the dentition.
• The most posterior wise crowns are always large in size, they are larger than the upper ones.
• As a rule, they have two roots that can grow together into one.
• The fissure tubercles are lower, blunt, and have a rounded shape.

The bottom row is located almost in a straight line. The crowns are inclined in the opposite direction than on the upper segment. Because of this, when the jaw bones are closed, the upper row is superimposed on the units of the lower jaw with a slight shift outward. The crowns of the 2nd molar tooth are slightly smaller than the coronal part of the first unit. The approximal surfaces are located almost parallel. They taper slightly at the neck. The vestibular surface is divided into 2 parts by a rather deep notch.

Complications during teething

• Delay in the appearance of permanent teeth.
  This may be due to genetic characteristics, immune system problems and a number of other diseases.
• Uneven teeth and other malocclusions.
• Hyperdentia.
  The child’s molar tooth (or teeth) grows in the second row. Hyperdentia, or supernumerary of teeth, is a fairly rare phenomenon, but requires the intervention of a dentist to eliminate the risk of malocclusion in a child.

Molar Differences

Often the surface of each molar tooth is shaped like a triangle. There is a certain number of tubercles on it, which take an active part in chewing food. The number of such tubercles may vary. Usually there are three, but sometimes there are more.

Such mounds are connected to each other by special ridges. On the upper and lower jaws the structure of these elements is different. In the upper dentition, the apex of the surface triangle is directed towards the tongue. This form is called a trigon. On the lower jaw, the apex of such a triangle is directed towards the cheek, which is called the trigonid. The size of the first and second types of teeth is practically the same.

Common problems with molars in children

Removing or retaining wisdom teeth

Even before the “eight” stage, you can discuss with your doctor how many of your 4 wisdom teeth to keep and how many to remove. Dentists believe that it is necessary to preserve third molars when:

• no signs of crowded teeth;
• the crowns of wisdom teeth are positioned vertically;
• first and second molars are missing.

Factors such as the lack of free space on the jaw play in favor of removing “eights”: the existing teeth are tightly spaced, there are no plans to remove the molars, their condition is good or excellent.

Other indications for removal:

• incorrect position of the tooth crown - horizontal or inclined, creating pressure on the roots and crown of the adjacent molar;
• prolonged lack of progress in teething in the presence of intense symptoms;
• repeated inflammation and suppuration in the eruption area;
• caries of the crown of the third molar.

They can be removed both before and after eruption. This procedure is painless and does not take much time. The procedure is performed under local anesthesia. Some clinics use sedation to make the procedure as comfortable as possible for the patient.

Care instructions

Molars in children require even more careful care than in adults. Frail enamel is much more susceptible to the effects of carious bacteria and the external environment, and the love of sweets and carbonated drinks does not add strength to it. When children develop a permanent bite, parents need to take special control of oral hygiene and diet (at least until the age of 14–15, when the teenager himself begins to realize the importance of dental health). In general, there are no difficulties here: in order to keep children's teeth strong and healthy, you need to follow several basic points.

• Daily hygiene.
  Brush your teeth at least twice a day, use dental floss and special rinses.
• Proper diet.
  Limit your intake of sweets and carbohydrates.
• Preventative visits to the dentist at least once every six months.
  If necessary, fluoridation and sealing of molars in children (so-called fissure sealing).
• Do not forget to wear a protective mouth guard during active games and sports.

Difference between molars and premolars

The main difference between molar teeth and premolars is their location on the jaw.
Premolars are located closer to the front of the dentition, and molars are slightly moved inward. Their quantity also varies. There are always two premolars on each side of the upper and lower jaws. There can be either two or three molars. Still others are also called “wisdom teeth.” They grow later than others and often appear only at 20-25 years of age. This process is often accompanied by malaise and fever. However, not all people on earth have third ones. A certain genetic predisposition can cause the absence of wisdom teeth in the oral cavity.