The vast majority of orthodontic consultations are related to jaw and tooth development problems. Dental formation begins in vitro (inside the womb) and continues throughout childhood and adolescence. Many of these problems have a genetic, i.e. hereditary, origin.
It takes several years of maturing before a tooth is fully formed and grows into the oral cavity. For example, the first adult molar (6-year-old molar) starts forming at birth, grows into the oral cavity by the age of 6 and has completed its development by the age of 10. Certain problems present in the primary dentition (milk teeth) will give clues to future malocclusions. A child with an agenesis (absence) of a milk tooth has a good chance that the underlying adult tooth will also be missing. As a general rule, by the age of 5, the anteroposterior relationship of the dental arches is a good indicator of the anteroposterior relationship of the permanent dentition (adult teeth). It’s interesting to note that many factors can influence a child’s orthodontic needs, including the premature loss of a baby tooth, which can have long-term adverse effects on the positioning and arrival of other teeth.
It’s much the same for jaw development: the growth of facial structures in humans follows certain rules. We can compare a child’s evolution with that of his peers to get clues about his development and the future alignment of his jaws. As a general rule, the closer a structure is to the brain, the sooner it will finish growing. It’s normal for a newborn to have a receding chin to allow passage through the vaginal canal during delivery. The jaw will complete most of its growth during adolescence. This makes it possible to diagnose problems in the child and use future growth to help correct them. Early orthodontic treatment for a patient with a strong chin (prognathism) at the age of 5 will minimize a problem that will only become more pronounced with time and growth.
Up to the age of 2, thumb-sucking does not cause malocclusion and should disappear as the child matures.
After pre-school age, if left unchecked or interrupted, this habit could lead to negative consequences for the dentition, such as an anterior gap.
A conservative approach before the onset of adult upper teeth, i.e. a verbal communication method accompanied by a reward or reinforcement system.
From the age of 6-7, when the adult teeth start coming in, a more direct approach is required: at-home approach (socks on both hands, bandage around the elbow to prevent the child from bending it) or braces. The braces, shaped like a tongue cage, are fitted in the mouth to make thumb-sucking uncomfortable. Gradually, the child will stop sucking his thumb. However, the device must be kept in the mouth for 9-12 months.
Removable devices are available to break this habit, but they require a great deal of cooperation from the patient. These acrylic appliances feature a metal cage, and the patient and parent become more responsible for the success of the treatment.
It’s very important to keep the space available for the emergence of the future permanent tooth. There are several appliances available.
The first is called a “Band and Loop”, and is used for a fairly young patient who has lost just one baby tooth. It is bonded to the missing tooth. It remains in place until the adult tooth grows in.
The second appliance, called a lingual arch, is designed to make room for several missing teeth. It is bonded to the back teeth and connected to a metal wire that runs behind all the teeth. It remains in place until the majority of adult teeth have erupted.
Favourable development in the growing child involves not only upper and lower teeth that close well together, but also jaws that are vis-à-vis, i.e. not out of line with each other.
Seen from the front, the upper jaw (palate) must be wide enough for all the upper teeth (dental arch) to overlap all the lower teeth. When the teeth fit well together, they function harmoniously and little tooth wear will occur in the medium to long term.
When the upper jaw is not wide enough (narrow dental arch, small palate or deep palate), a cross-bite occurs: the teeth close in reverse (one or more upper teeth are placed inside the lower teeth). The teeth don’t meet well together, and abnormal wear is more likely to occur as a result of chewing.
Since the upper teeth are locked inside the lower ones, this also has the effect of limiting the growth of the upper jaw in width, and the palate will remain narrow for life in the absence of orthodontic treatment. Associated problems will result: premature wear and aging of the dentition, narrow airways and mouth breathing, gum problems (thin gums, recession and loosening), predictable repercussions on the jaw joints (temporomandibular joints), etc.
The upper jaw (maxilla) and lower jaw (mandible) are closely linked. Like communicating vessels, the development of one automatically influences the behavior of the other. For example, if the upper jaw does not grow sufficiently (deep palate), the lower jaw will develop asymmetrically (more to the right or more to the left). Without orthodontic treatment at an early age, permanent facial asymmetry or asymmetrical growth will result. The child who becomes an adult will have a deformed face with a deviated chin for the rest of his or her life.
At a young age (before puberty), correcting a narrow palate is quick and easy, since the jaws are flexible and still growing. Later in adulthood, more invasive procedures are required (palate surgery or jaw surgery, also known as orthognathic surgery).
Just as the upper and lower jaws are not out of alignment when viewed from the front, they must also be aligned or facing each other when viewed from the side or profile.
In the case of skeletal disharmony or misalignment of the front and rear jaws (side view), the teeth forming part of the jaws are also misaligned. The upper and lower teeth do not fit well together, and tooth wear problems will occur in the medium to long term.
When the upper jaw is too far forward (protruding teeth or buck teeth) or the lower jaw is not growing sufficiently (receding chin or receding profile), an excess of space (horizontal overhang or “overjet”) is visible. This condition is called upper jaw prognathism or lower jaw retrognathism.
Viewed from the side, when the upper jaw is underdeveloped and set back, or when the lower jaw is too far forward (chin prominent), the lower teeth protrude beyond the upper teeth (“cross-bite”). This jaw condition is also known as retrognathism of the upper jaw or prognathism of the lower jaw.
Diagnosed at an early age (prepubertal period), these two conditions (dento-skeletal disharmony) are easily corrected: stimulate the child’s development (amount and direction of growth) by wearing appliances specifically designed to influence proper jaw growth (functional or myo-functional appliances). This non-invasive approach is also known as dentofacial orthopedics or growth stimulation. In adulthood, depending on the severity of the misalignment, the same correction will be more limited (compromise of results) and may require more complex approaches such as jaw surgery (orthognathic surgery).
A harmonious, functional and healthy dentition means that all upper teeth (upper dental arch) touch all lower teeth (lower dental arch): all contacts between upper and lower teeth are evenly distributed, and all teeth chew equally. This correct arrangement and alignment of teeth prevents premature tooth wear (loss of enamel).
Anterior open bite: the front teeth do not touch when the back teeth are closed together.
Posterior open bite: back teeth do not touch when front teeth are closed together.
Anterior or posterior open bite makes chewing difficult and predisposes to abnormal wear of the only teeth in contact. Both conditions have a negative impact on swallowing (atypical swallowing or lingual propulsion), pronunciation (phonetics) and jaw joint function.
Tooth agenesis, i.e. the absence of a tooth, can occur in the primary dentition, although much less frequently than in the permanent dentition (adult dentition). Agenesis is a process that is becoming more and more frequent, and usually involves the last tooth of the same type to grow, such as the lateral incisor, the 2nd premolar and the famous wisdom teeth (the 3rd molars). Congenital absence can present itself in different levels of severity: anodontia (absence of all teeth), oligodontia (absence of more than 6 teeth) and hypodontia (absence of 1 to 6 teeth). Several factors are linked to the origin of congenital absences, and many factors need to be assessed in order to plan appropriate management of this problem.
The presence of supernumerary teeth, i.e. extra teeth, is also genetic. This phenomenon can occur in both primary dentition (baby teeth) and permanent dentition (adult teeth). In fact, if a primary tooth is present in the primary dentition, 1 in 3 patients will also have a supernumerary tooth in the same place in their permanent dentition. The most common supernumerary tooth is called the mesiodens, and is located between the 2 upper central (palatal) teeth. Supernumerary teeth generally cause or exacerbate a lack of space. They can also get in the way, blocking or redirecting the eruption of “normal” teeth. Panoramic X-rays are suggested around the age of 8-9 years, in order to diagnose them early and plan their timely management, while minimizing potential damage to adjacent teeth.
It may turn out that baby teeth are fused to the bone and are not exfoliating normally. In other words, the tooth is set in the bone, and the natural process of the tooth falling out to make way for the adult tooth is not occurring, or is less effective. The teeth around the ankylosed tooth grow in during growth, while the ankylosed tooth remains in place, creating a bone defect, among other things. Adjacent teeth can migrate and converge over the ankylosed tooth, limiting the space available for the next adult tooth. Ankylosed teeth are more common in the lower jaw. An ankylosed tooth can also be a precursor to the absence (agenesis) of the underlying permanent tooth. It’s important to consult an orthodontist to assess the long-term impact of an ankylosed tooth on your child’s dental development. In some cases, an ankylosed tooth can delay the eruption of an adult tooth by up to 6 months.
The process of tooth eruption and replacement of a baby tooth by an adult tooth follows a very precise sequence. Certain factors can influence this sequence, either by delaying, accelerating or interrupting it. Premature loss of a primary tooth (a baby tooth that falls out or has to be removed before its time) is often due to the presence of large cavities. Nature doesn’t like a vacuum, especially in the mouth, so the teeth adjacent to the hole will migrate into the space to reduce or fill it. This will reduce the space available for the next permanent tooth. It’s important to remember that the premature loss of a primary tooth will almost always have the effect of slowing the growth process of the adult tooth, leaving time for the adjacent teeth to migrate further into the hole. To maintain the necessary space and prevent migration of adjacent teeth, the use of a space maintainer is often recommended. There are various types available, depending on the condition of your child’s mouth and his or her needs.
Sufficient space in the jaws is a minimum requirement for straight teeth. A lack of genetic or developmental development of the jaws inevitably leads to overlapping teeth.
Teeth can also be crooked as a result of poor positioning of tooth buds or poor eruption of teeth caused by various obstacles, such as primary teeth that refuse to fall out.
In any case, an orthodontic examination will help to find the cause and intervene at the right time. Ideally, all children should have an orthodontic examination from the age of 7. Why? Because at this age, orthodontic intervention can modify the growth of the jawbone to avoid the worst.
Overbite is the overlapping of the lower teeth by the upper teeth. This overlap, often called “overbite” in the general population, should be between 20% and 50%. When overbite exceeds these limits, the chances of premature tooth wear are greatly increased. Orthodontic follow-up is then recommended to avoid this accelerated wear.
Exaggerated gaps between baby or adult teeth can sometimes be observed in children. The most common causes are either inadequate lingual posture or a lack of harmony between tooth and jaw size. In both cases, a visit to the orthodontist is necessary to manage the situation. In the first case, the orthodontist may refer the child to a speech therapist. A combination of causes is always possible.
A tooth is impacted when it has not yet emerged from the mouth, when it should according to chronology, and when its root is at least half developed. In children, the most frequently impacted tooth is the upper canine. This type of anomaly can occur unilaterally (on one side) or bilaterally (on both sides). It’s vital to consult an orthodontist immediately, as the prognosis diminishes rapidly over time.
The longer you wait to intervene, the more you expose yourself to complications. Examination too late can lead to the need for traction surgery. Resorption of neighbouring teeth (root damage) can also occur, up to and including the loss of an upper incisor (a “paddle” or lateral).
Occasionally, there is an exaggerated space between the two central incisors (the paddles). The most frequent causes are delayed eruption of adjacent adult teeth, or the presence of an exaggeratedly large labial frenulum (fillet of the lip). Both situations merit a visit to the orthodontist, who will advise you on the measures to be taken.
The eruption of baby and adult teeth requires extraordinary coordination. Occasionally, a baby tooth refuses to erupt in the desired sequence. An orthodontic examination can help determine the best time to extract the problematic tooth, since extraction too early or too late can bring its own set of problems.