Kids, Teens and Mixed Dentition

Kids, Teens and Mixed Dentition: At age 6, the 6th tooth appears at the back of the dental arch. This tooth is the first permanent molar! It's not a baby tooth; it won't fall out. It's meant to stay for life. Until then, there were only cute little teeth.

Suddenly, an ugly duckling appears: It is larger than all the others and has a stronger, darker color than all the others with the first set of teeth. Its appearance is more robust, stronger. It inaugurates the mixed dentition phase.

In mixed dentition, we see the coexistence of deciduous and permanent teeth. But gradually the deciduous teeth are replaced by permanent teeth. Finally, by age 12, 28 permanent teeth will have replaced the 20 deciduous teeth.

Kids, Teens and Mixed Dentition

Initially, the first set of teeth – deciduous teeth – affectionately called "baby teeth," consists of 20 teeth, 10 in the maxilla and 10 in the mandible. In each hemi-arch, we have 1 central incisor, 1 lateral incisor, 1 canine, and 2 molars. Baby teeth begin to erupt during the first 6 months of life. By approximately three and a half years, the set is complete. But between 6 and 7 years of age, an odd one out appears: the first permanent tooth, which will erupt one on each side of the mouth, in the maxilla and mandible.

Kids, Teens and Mixed Dentition

Mixed dentition

So, from that moment until age eleven, when the last deciduous tooth exfoliates (falls out), we will be in the "mixed dentition" period, as it is composed of both temporary and permanent teeth. The number of permanent teeth increases while the baby teeth fall out until there are 28 teeth by age 12. Then, only from age seventeen onwards will the third molar appear, and the complete permanent dentition will have 32 teeth.

Above all, when the first molar erupts, the child is at an age (6 years old) when parents have no idea that they already have a permanent tooth in their mouth. This can be a problem because, in addition to parents not noticing its arrival, at that age the child does not have good motor coordination to brush efficiently, and unfortunately, this tooth often ends up decayed by adolescence. Sometimes it has to undergo root canal treatment.

Finally, this tooth is very often lost as a result of the high degree of destruction it suffers in the first few years following its eruption. However, it is a very important tooth for chewing. It is one of the "pillars" upon which the articulation between the maxilla and mandible is established. The loss of this tooth can determine whether or not a child will need orthodontic treatment and can have lifelong consequences.

Kids, Teens, and Mixed Dentition: Important information about mixed dentition.:

Normal chronology of permanent tooth eruption.

First lower and upper molars (at 6-7 years old)                       

Lower central and lateral incisors (at 6-8 years of age)

Upper central and lateral incisors (at 7-8 years old)

First lower and upper premolars (at 9-10 years old)

Upper and lower canines (at 9-12 years old)

Lower and upper second premolars (at 10-12 years old – The first and second deciduous molars will be replaced by the first and second permanent premolars)

Lower and upper second molars (at 11-13 years old)

Third molars, also known as "wisdom teeth" (usually between the ages of 17-25)

Loss of baby teeth: As permanent teeth erupt, baby teeth begin to loosen and eventually fall out. This naturally occurs due to the resorption of the roots of the baby teeth and the pressure exerted by the growing permanent teeth beneath the deciduous teeth.

Kids, Teens, and Mixed Dentition

Kids, Teens, and Mixed Dentition

Care during mixed dentition:

The mixed dentition phase is perhaps the most critical regarding the threat of caries. It is when young people become more independent in their food choices and meal times, and when they are less likely to be supervised. At this time, attending school and being away from parents greatly increases the chances of them preferring foods with a higher cariogenic potential and not yet having the responsibility of brushing their teeth.

 There is the aggravating factor that during the first 5 years after the eruption of a permanent tooth, there is a period called "enamel maturation," which is a biochemical process that occurs on the tooth surface. While this process is not progressing, the newly erupted tooth is more vulnerable to attack by the acids in bacterial plaque.

The eruption of premolars and molars also brings with it the presence of grooves called pits and fissures – the well-known dimples present on the food grinding surface (occlusal surface). This area is the main vulnerable point for caries. As you can see in the photo in Figure 2, the depth of these grooves helps to retain starch and other high-calorie foods, making it difficult for the toothbrush bristles to be effective.

Tooth decay in permanent and primary teeth

This is the age group most threatened by cavities. In addition to establishing good oral hygiene practices and maintaining discipline, dentistry offers a method to help prevent cavities on the chewing surface; this method is called the application of... Pit and fissure sealant. What is that?

In molars and premolars, we find those little pits where food is ground. These pits can have very deep grooves that a toothbrush cannot reach. Consequently, the fermentation that bacteria will cause on the starch and sugars deposited there will, after some time, lead to the development of cavities.

This is the most common type of cavity. Cavities in the chewing grooves.

The sealant can be applied in two situations.:

Non-invasive techniqueThe sealant is applied to pits and fissures without mechanical preparation using a dentist's drill, meaning where the tooth surface has not yet been affected by cavities.

Invasive techniqueIt's necessary to open the tooth a little with the dentist's drill to make sure there's no deep cavity, or simply to remove a very small cavity where the tooth has darkened pits.

It is a low-cost technique, no anesthesia is required. It preserves the natural structures of the tooth. The sealant releases fluoride, protecting the surrounding areas, and is tooth-colored.

Kids, Teens and Mixed Dentition

Common problems during mixed dentition:

Delayed eruption of permanent teeth: In some cases, permanent teeth may take longer to erupt than expected. If there are concerns about this, it is advisable to consult a dentist.

Dental agenesis: In some cases, a permanent tooth may not develop to replace a baby tooth. This is known as dental agenesis and may require dental intervention, such as prosthetics or dental implants.

Malocclusion: Sometimes, permanent teeth may not align properly with the remaining baby teeth, resulting in occlusion problems. Therefore, the dentist may recommend orthodontic treatment if the malocclusion is significant.

Types and Severities of Malocclusions

Misalignment can be a mild deviation limited only to the positioning of permanent teeth that gradually replace baby teeth. However, certain bone discrepancies can manifest, making these deviations more severe and leading to crossbites, where the relationship between the upper teeth of the maxilla and the lower teeth of the mandible is reversed.

What do we mean by "invert"? One of the fundamentals of a normal occlusal relationship is the fact that the upper teeth are always positioned to cover the lower teeth. In other words, the tips of the lower teeth are hidden by the incisal edges of the upper teeth.

Subsequently, this type of crossbite can stunt the growth of the upper jaw, leading to the formation of a high-arched palate, or mandibular growth that results in an unfavorable facial profile, known as Angle Class III.

Mouth breathing

Mouth breathing, which occurs when a child or adolescent breathes primarily through their mouth instead of their nose, can have significant impacts on facial development and maxillomandibular growth. This can be related to problems such as rhinitis and nasal congestion. Let's explore these problems in more detail:

Kids, Teens and Mixed Dentition

1. Unfavorable Facial Development:

Chronic mouth breathing can lead to changes in facial development, resulting in features such as a receding jaw, a narrower chin, and an open mouth. These changes can affect facial aesthetics and the harmony of facial structures.

2. Dental Malocclusion:

Mouth breathing can interfere with proper functioning. teeth alignment and bite, This can lead to malocclusion problems such as overbite, open bite, or crossbite. Orthodontic treatment may be required for correction.

3. Impaired Maxillomandibular Growth:

Improper mouth breathing can affect the normal growth of the maxillary and mandibular bones. The pressure of the tongue on the roof of the mouth plays an important role in the proper development of these bones. Mouth breathing can cause an imbalance in this pressure, resulting in altered maxillomandibular growth.

4. Muscle Changes:

Mouth breathing can lead to weakening of the facial and tongue muscles, since these muscles are not being used correctly during breathing. This can negatively influence the development of facial muscles and the position of the jaw.

5. Rhinitis and Nasal Congestion:

Problems in the upper airways, such as allergic rhinitis or chronic nasal congestion, can lead to a greater likelihood of mouth breathing, since breathing through the nose becomes difficult. Similarly, constant nasal congestion can create a vicious cycle, perpetuating mouth breathing and aggravating facial and maxillomandibular development problems.

6. Changes in Body Posture

Mouth breathing can influence body posture, since the way a child holds their head and shoulders can be affected by the attempt to facilitate breathing. Furthermore, it can contribute to postural imbalances.

Finally, it is important to highlight that these problems can vary in severity and impact from person to person. Appropriate treatment may include identifying and treating the underlying causes of mouth breathing and involving specialists such as otolaryngologists, speech therapists, and orthodontists to help correct facial and maxillomandibular development problems associated with mouth breathing.

Therefore, pay attention to these signs in your child: Observe when he or she is sleeping or even distracted watching television. Notice if they always breathe through their nose. Record the frequency and duration of episodes of rhinitis or colds. A prolonged episode can lead to a bad breathing habit. Seek help.

Author: Nivaldo Pinho Gonçalves, Periodontist, CROSC 9696.

Suggestion: https://pt.scribd.com/document/230656164/Moyers-pdf