Malocclusion can occur for many reasons. The main risk factors are disorders of hormone secretion, taking medications in the womb, and some diseases up to the 3rd month of pregnancy. How does the neonatal period affect the later jaw configuration and what types of malocclusion can be distinguished?

The history of orthodontics goes back many centuries. Scientists discovered mummies whose teeth were connected with wires to align their position, and in 400 BC Hippocrates wrote about attempts to “straighten the bite”. The first attempts at orthodontic treatment were driven mainly by the desire to improve the appearance. Today we know that not only aesthetics matters.

Why do some people develop malocclusion?

This question has kept many dental scientists awake at night for years. Only the rapid development of orthodontics in the 20th century allowed for a significant expansion of knowledge in this field. It turned out that giving an unambiguous answer is very difficult. There are many factors contributing to the formation of malocclusion. Moreover – these factors additionally overlap and modify their influence.

It is also worth noting that fetal development and childhood have a special influence on the development of a child’s dental arches.Any nutritional deficiencies, bad habits or injuries will be affected. Therefore, parents should be aware of the risk factors for malocclusion, because appropriate prophylaxis may save long-term and costly treatment in the future.

Bite defects – risk factors

General factors influencing the formation of malocclusion:

1. Hormone secretion disorders, resulting in:

• gigantism,
• acromegaly,
• pituitary dwarfism,
• hypothyroidism,
• rickets.

2. Drugs in the fetal period (sulfonamides, thalidomide, quinine)
3. Diseases up to the 3rd month of pregnancy:

• viral (rubella, flu, common inflammation of the salivary glands, the so-called “mumps”, measles, chicken pox, shingles, herpes simplex),
• parasitic (toxoplasmosis, listeriosis),
• general (diabetes, circulatory failure).

4. Factors influencing the pregnant woman and the fetus:

• vitamin deficiency (especially A and B2),
• malnutrition,
• misalignment of the fetus,
• injuries during pregnancy,
• complicated childbirth.

5. Local factors:

• incorrect position of the child during sleep or feeding,
• posture defects,
• swallowing abnormal surviving infant type of swallowing,
• mouth breathing
• tonsil overgrowth,
• chewing disorders (e.g. one-sided chewing),
• habits, the so-called parafunctions: sucking (with a pacifier, finger, lips, cheeks, etc.), biting (of nails, pens, pencils, etc.), teeth grinding,
• caries,
• injuries,
• diseases of the temporomandibular joint.

Malocclusion – causes

1. Gigantism, acromegaly and pituitary dwarfism

These three conditions are caused by a disturbance in the secretion of growth hormone by the pituitary gland. As growth hormone regulates, among other things, bone formation, it also influences the development of the maxilla and the mandible.

2. Hypothyroidism

Hypothyroidism is associated with many symptoms, but several of them are of particular importance in the development of malocclusion. They belong to their:

• delay in bone maturation,
• underdevelopment of the middle part of the face,
• big language.

3. Rickets

Ricketsis a disease caused by a deficiency of vitamin D, which regulates the body’s calcium and phosphate balance and is responsible for bone mineralization. In the craniofacial area, rickets is characterized by the following symptoms: flattening of the anterior part of the mandibular alveolar ridge, tongue shrinkage, a V-shaped jaw with a high and narrow palate, elongation of the lower face, and enamel underdevelopment.

Malocclusion and pregnancy

Factors influencing a pregnant woman

The first two months of pregnancy are especially important for the proper development of the fetus. This is when the most important organs form, including the head area. During this period, the embryo is very sensitive to the effects of any harmful factors (trauma, toxic substances, drugs, lack of necessary nutrients, etc.).

Malocclusion and the position of the newborn

Incorrect position of the baby during sleep or feeding

The first months of life, the baby spends mainly lying down, sleeping. The position he is in is very important for the proper development of his spine’s curvature and bite. If the child is placed on a pillow that is too high, it will result in the jaw andtonguesticking out excessively (it may form an under-bite). In turn, excessive bending of the head back during sleep will cause thelower jaw to retract in the future (overshot bite).

Children often have the habit of putting their fist, hand or arm under their face while they sleep. From an orthodontic point of view, this is a bad practice that can lead to a narrowing of the jaw and the formation of a cross bite.CAUTION!!! Children should sleep with their head on a small pillow with the spine flat.

Malocclusion and feeding a newborn

Newborns are born with a physiologically retracted lower jaw. Natural breastfeeding stimulates its proper development towards the front. However, if you do need to bottle-feed your baby, always buy a teat that closely follows the natural shape of the nipple, e.g .:

• Dreyfus soother,
• Mueller-Balters teat.

Such teats are available in pharmacies.CAUTION!!! Your baby should be breastfed in the most upright position.These indications should not be underestimated, as the feeding time takes an average of 20 minutes and is repeated 6-7 times a day.

Bite defects – cons of bottle feeding

Why is artificial feeding less beneficial to my baby?

1. During natural feeding, the baby uses complex movements that stimulate the development of its facial skeleton. In turn, when feeding with a bottle, it actually only uses the tongue to suck.
2. During artificial feeding, babies often suck their cheeks between their side teeth, which contributes to the formation of an open bite in these places.
3. Artificial feeding makes your baby lazy so that she may not want to suckle later.
4. The lack of natural muscle exercise such as breastfeeding can make it difficult to learn to chew food in the future.
5. Artificially fed babies get used to sucking a finger or a nipple more easily.

Taking into account the correct bite formation in a child, at around 3 months of age, you should start feeding semi-liquid and pasty food with a spoon. Around 5-7 months, the first milk incisors erupt and from that moment on, it is also recommended to give bread while feeding. Thanks to this, the child learns the chewing activities.

Malocclusion and body posture

Incorrect posturecan also cause malocclusion.Scoliosis,especially in the thoracic segment, predisposes to lateral displacement of the mandible. On the other hand, deepenedcervical lordosismay result in the formation of an overshot bite.

Malocclusion – How does a baby swallow?

The infant type of swallowing survived

When swallowing, adults press the tongue against the roof of the mouth, while keeping the dental arches tight. This is completely different for babies. Children swallow food with their jaws open, moving the tongue forward and placing it between the gums. They engage completely different muscles than adults. Normally, infantile swallowing should begin to subside around 18 months of age. If it persists over the age of 4, it causes severe malocclusion. The forward tongue causes the teeth to shift and it is impossible to connect the upper and lower incisors.

Bite defects – mouth breathing

Normally, you should only breathe through your nose. The proper structure of the respiratory tract makes the inhaled air purified, moisturized and heated before it reaches the lungs. Moreover, only breathing through the nose gives the body the right amount of oxygen.

Mouth breathing predisposes to the formation of:

• malocclusion,
• caries,
• tartar build-up,
• respiratory and periodontal diseases.

Only 20% of it is caused by anatomical abnormalities (e.g. a curvature of the nasal septum), and in 80% it is an acquired disease. Mouth breathing is often accompanied by the so-called the third tonsil (i.e. the oversized tonsil).

Malocclusion and tonsil hypertrophy

The tonsil most often overgrows is the pharyngeal tonsil.It causes reflex mouth breathing and, consequently, the formation of a back jaw. The second place is the palatine tonsils, which are located on the sides of the base of the tongue. In order to “unblock” the airways, the child reflexively protrudes the lower jaw, which leads to the fixation of the front jaw.

Malocclusion – chewing disorders

For the developing baby, it is important not only what it eats, but also in what form. The gradual introduction of harder and harder foods into the diet stimulates the development of the jaws and chewing muscles.Feeding only the pulp contributes to the formation of jaw constrictionand tooth crowding. It should also be remembered that the early loss of some teeth (e.g. due to tooth decay) may force the child to chew food unilaterally, which in turn will affect the bite.

Malocclusion – parafunctions

Parafunctions are abnormal habits, unconsciously and repeatedly.The parafunctional functions that may favor the formation of malocclusion include:

• sucking (with a pacifier, finger, lips, cheeks, etc.),
• biting (of nails, pens, pencils, etc.),
• teeth grinding.

Sucking on a finger, a pacifier, etc. should stop after the baby is one year old. Otherwise, the mandible will retract and the upper incisors will tilt outwards. The habit of sucking on the lips or cheeks, on the other hand, will prevent the opposing teeth from touching where the baby is biting the cheek. In addition, the lower incisors are also withdrawn.

Malocclusion and teeth grinding

Teeth grinding most often occurs at night, during sleep, and is calledbruxism. It contributes to the abrasion of tooth cusps, making the teeth shorter. The height of the occlusion is lowered, which in turn may cause pathological changes in the temporomandibular joints, which include:

• pain,
• with cracks
• jumping around.

Ailments of the temporomandibular joints due to bruxism usually concern girls in adolescence. Most often they are associated with stress or excessive susceptibility to it.

Occlusion defects, caries and injuries

Milk teeth are less resistant to caries than permanent teeth,which means they are lost more often. It has a very bad effect on the child’s bite, because the milk teeth “hold a place” for the permanent teeth. Their early loss contributes to significant displacements of the emerging teeth (there is crowding or lack of space for emerging teeth, especially molars).

Children are a group particularly vulnerable to injuries that can lead to:

• distortions,
• tooth loss (effects similar to caries),
• damage to the buds of permanent teeth.

Boys whose upper incisors are excessively inclined towards the lip are particularly vulnerable. As as many as 30% of them suffer injuries to these teeth, it is worth considering their orthodontic treatment.

Diseases of the temporomandibular joint

Diseases of the temporomandibular joint often lead to its stiffness. This immobilizes one of the mandibular condylar processes, preventing its proper development. If stiffness occurs on both sides, the mandible does not expand forward and remains retracted, giving the so-called “Bird profile”.

The revival of permanent teeth is a very complicated and precise process.Milk teeth somehow “hold space” for permanent teeth and therefore their premature loss may contribute to the formation of malocclusion, for example:

• The premature loss of the milky upper molars can result in a cross bite.
• The premature loss of the milky upper molars can resultin a sloping bite.
• Premature loss of the upper incisors causes undershot bite, and the lower incisors cause overbite.
• Premature loss of any milk tooth will contribute to the formation of dense bone tissue above the permanent tooth bud. This could be the cause of the tooth retention.

CAUTION!!! In 27% of children with malocclusion, these disorders were caused by premature loss of primary teeth.

Malocclusion – when do we deal with them?

Although the teeth vary greatly in shape, size and color in individuals, their mutual position and the ratio of the upper and lower dental arches are subject to very strict rules.

Therefore, if you want to know what is and what is not a malocclusion, you first need to know these universal standards:

1. The shape of the upper and lower dental arch should be regular and symmetrical, resembling a semicircle. Individual teeth in the arch should be in contact with each other on their side surfaces.
2. The upper tooth should be in contact with the two lower teeth, except for the medial lower incisors and lower eights. For example, the upper medial incisors should be in contact with the lower medial and lateral incisors after occlusion, etc.
3. The upper dental arch is slightly larger than the lower one and therefore the upper teeth are somewhat in front of the lower teeth, i.e. the upper cheek cusps of the lateral teeth touch the cheek walls of the lower teeth. In turn, the buccal cusps of the lower teeth are located in the grooves running through the center of the chewing surfaces of the upper teeth.
4. The upper incisors should cover the lower one 1/3 of their height (maximum of the length). If they cover to a greater extent, we are dealing with a deep bite.
5. Orthodontics has two very important classifications based on the position of the canines and the first upper and lower molars during the occlusion of the dental arches:

• In a correct bite, the upper canine is located between the lower canine and the first premolar. In the undershot bite between the lower premolars, and in the rear bite between the canine and the lower lateral incisor.
• The standard assumes that the anterior buccal cusp of the first upper molar is located between the buccal cusps of the first lower molar.

Malocclusion – types

There are the following malocclusions:

• partial cross bite (anterior, lateral),
• total cross bite,
• lateral displacement of the mandible,
• overhang bite (unilateral, bilateral),
• undershot bite,
• backside,
• Undershot mouth
• open bite,
• deep bite,
• crowding of teeth,
• tooth abnormalities: structure disorders, number disorders, position disorders, eruption disorders,
• foreleg.

Malocclusion – cross bite and cross bite

In normal conditions, the upper teeth “protrude” in front of the lower teeth, ie the buccal cusps of the upper teeth are in front of the buccal cusps of the lower teeth.In the case of a cross bite,the lower teeth overlap the upper teeth in some sections or throughout the arch (partial and complete).

An overhang biteis the opposite of a cross bite and results from a widening of the jaw or a narrowing of the lower jaw. The lingual cusps are located in front of the buccal cusps of the lower teeth, as if the maxilla embraces the mandible from the outside. This defect prevents proper chewing as the lateral movements of the lower jaw are very limited.

Malocclusion – lateral displacement of the lower jaw

Lateral displacement of the mandiblemay be functional or morphological. Functional means that a properly built mandible is displaced to one side for various reasons. Morphological, however, is caused by disturbances in the structure of the mandible – one of its sides is somewhat more developed or, on the contrary, reduced. Morphological and functional displacement can be distinguished from each other by a simple test. It is enough to move the mandible to the correct, symmetrical position in relation to the maxilla. In the case of functional displacement, the appearance of the face and bite will significantly improve (it will become symmetrical), while in the case of a morphological displacement, the appearance and bite will deteriorate.

Malocclusion – undershot and undershot bite

A oversized biteis a defect that causes the lower jaw to move backwards in relation to the upper jaw. In people with an overshot bite, the retraction of the chin and the drooping corners of the mouth are noticeable. This defect may be caused by insufficient development of the alveolar part or the entire mandible (so-called retrogenia), or excessive growth of the jaw.

In frontal defects, the lower teeth protrude in front of the upper teeth, which gives the face an aggressive, unpleasant appearance. Similarly to undershot bite,undershot bite can be caused by excessive development of the alveolar partor the entire lower jaw (so-called progenia), or insufficient growth of the jaw.

Malocclusion – open bite and deep bite

Under normal conditions, the upper teeth should be in contact with the lower teeth when they engage. There is a gap between the teethin the open bite .If the defect affects only part of the teeth, no change in facial features is visible. However, if it affects the entire dentition, the lower part of the face is significantly elongated. An open bite prevents proper chewing and can cause speech impediments.

A deep biteis based on a greater proportion of the upper incisors overlapping the lower ones (i.e. the lower incisors are covered by the upper incisors by more than 1/2 of their height). In extreme cases, the upper incisors can even nibble at the mucosa in the mouth vestibule, and the lower ones at the palate mucosa. The lower part of the face is then shortened.

Malocclusion – crowding of teeth

Tooth crowdingis often caused by teeth that are too large in relation to the alveolar process. In children, crowding is common due to the premature loss of deciduous molars, which have “held up” space for permanent molars. The crowding of the teeth causes their rotation, delayed eruption, eruption in the wrong place (e.g. from the atrium or on the palate), or even stopping (a permanent tooth for which there is no space in the arch remains in the bone).

Malocclusion – tooth abnormalities

1. Tooth structure disorders– teeth can be significantly enlarged in relation to the alveolar process (large teeth) or smaller (small teeth). Sometimes it also happens that two teeth join together due to developmental disorders (fused, fused and twin teeth).
2. Teeth abnormalities– can refer to both increasing and decreasing their number. Among the supernumerary teeth, the so-called mesiodens, i.e. an additional upper medial incisor. Usually it is smaller and is removed for aesthetic and prophylactic reasons. When the number of permanent teeth is reduced, third molars, premolars and upper lateral incisors are most often missing.
3. Tooth position disturbances– usually occur due to specific anatomical conditions (e.g. tooth arch that is too short, etc.) or are caused by past injuries.
4. One of the types of position disorders is the so-calledtransposition, which consists in changing the order of the teeth in the arch. It usually affects the upper canines, which take the place of the central incisors or premolars. Other disorders include tooth inclination and rotation.
5. Diastemais the gap between the upper medial incisors. It is usually caused by an excessively large upper lip frenulum or the absence of lateral incisors. It occurs physiologically in children before the lateral incisors erupt.
6. Re-inclusion is, as it were, the opposite of tooth eruption and consists in their re-entering the gum and alveolar bone. Scientists have not been able to come up with one coherent theory why some of them, when properly eroded, become reincarnated. This process usually affects deciduous molars and is an indication for their removal.
7. Eruption disorders – a shift by more than a year in relation to the norms of eruptionis considered a disorder of the ejection of permanent teeth. For deciduous teeth, the period of acceptable differences is much shorter. Eating disorders include:

• Premature eruption of milk teeth – it happens that newborns are born from the so-called congenital teeth, which are usually the lower incisors. These teeth have an abnormal structure, they do not have a root, and they make breastfeeding difficult, therefore they are surgically removed. Another type of this type of irregularity are the so-called newborn teeth that erupt up to one month after birth. Their presence may indicate a hormonal disorder in the child.
• Delayed eruption of deciduous teeth – is the initiation of teething in a child after the first year of life. It is usually accompanied by rickets, malnutrition and hypopituitarism.
• A surviving tooth – this is a situation in which, after the period of replacement of milk teeth permanently, a milk tooth remains in the oral cavity. This usually happens when the root of a permanent tooth is missing or the tooth has been retained and is stuck in the alveolar bone.
• An impacted tooth – it is a properly developed tooth which, for various reasons, did not erupt on time and is completely embedded in the alveolar bone of the maxilla or mandible.