Malocclusion

The severity of the signs of malocclusion varies based on the class it belongs to. Anyway, the typical sign of malocclusion is the evident misalignment of the teeth. This causes a series of other complications which define the clinical presentation. These include the possible alteration of the features of the face, due to the skeletal disharmony, a frequent biting of the inner cheeks and tongue, due to the not-aligned upper and lower teeth which tend to hit other parts of the mouth, and the consequent discomfort felt by the subjects while chewing or biting. In the most severe cases subjects might even experience speech problems, like the development of a lisp, as well as the tendency to breathe through the mouth rather than the nose.

Malocclusion is easily diagnosed through routine dental examination, where the shape and the relative positions of teeth are carefully examined with a physical examination or with the help of X-rays. If a form of malocclusion is detected, it is classified based on its type and severity. As previously seen, malocclusion has been classified in three major types:

1. Class I: The upper teeth slightly overlap the lower ones. In this case, the bite is normal and the overlap is barely detectable. This class represents the most common form of MO among the subjects affected. Classical complications of this form include spacing, crowding, and over/under eruption. This form is also called neutrocclusion. 
2. Class II: The upper teeth severely overlap the lower ones. This dental condition is also called retrognathism, retrognathia, distocclusion, or overjet. Class II is particularly frequent among people with Caucasian origin. 
3. Class III: The lower teeth and jaw severely protrude forward, markedly overlapping the upper teeth and jaw. Very often patients have a large mandible or a short maxillary bone. This condition is also called prognathism, mesiocclusion, or negative overjet, and is particularly frequent among people of African or Asian origins. 

This classification was devised by Edward Angle himself by imagining a line of occlusion on which all teeth should fit. Any variation from this point of reference is considered a form of malocclusion. There are also many other conditions which do not directly relate to this type of classification. The most common of these other problems is crowding, defined as the condition of insufficient room between teeth to allow their proper alignment and development.

In the majority of the cases, with people showing mild forms of malocclusion, no major treatment is required, and patient can do well without medical help. On the contrary, if a more severe form of malocclusion is detected, this is treated according to the severity of the condition itself. The major treatments for the subjects affected include braces to correct the position of the teeth, removal of the teeth in the cases of overcrowding, or physical modification of teeth, like reshaping, binding, or capping, to improve their general arrangement in relation to each other and to the jaws. In the worst cases, the treatment might also consist of dental surgery, to reshape or shorten the jaws, or the addition of wires and plates to stabilize jaw bones.

Unfortunately, complications are frequent and might include tooth decay, pain or discomfort, and irritation of gums due to the application of dental devices. Some patients might even experience difficulty in chewing and speaking while the treatment is underway.

The prognosis is generally good, with the treatment resulting in the correction of the dental problem, especially when the patients is treated very early. Furthermore, early treatment also reduces the time needed to get to a complete resolution of the dental misalignment and markedly reduces medical costs. Prognosis can be good also for adults, provided that they get professional medical help. However, in these cases treatment takes longer and is much more expensive, because the bones in older subjects are no longer soft and teeth are moved with more difficulty. This means a longer use of braces or other dental devices.

Dental treatment might cause possible complications, which include tooth decay, discomfort, irritation of gums due to the application of dental devices, and difficulties during chewing or speaking.

Malocclusion is usually an inherited condition passed down from generation to generation. However, the shape, position, and structure of teeth might change as a consequence of pressures frequently exerted on them by several external stimuli. These stimuli include a series of conditions and habits which, working as etiological factors [1] [2], influence the development of the face and dental arches [3] [4] [5] [6] [7] as well as the skeletal growth [8] of the teeth. The habits include prolonged use of bottle feeding and thumb sucking in early childhood, as well as the use of pacifiers after the age of 3. The prolonged use of pacifier has also been correlated with other medical problems like otitis [9] [10]. The medical conditions that influence the development of teeth, instead, include injuries, tumors of the mouth and jaw, disorders of deglutition and poor dental care.

The prevalence of malocclusion is much higher in the developing countries than in the developed ones, because of the much poorer dental care conditions. For instance, the prevalence is around 67,82% among Chinese children and around 34% among American whites. Prevalence also tends to be higher among children than adults, perhaps always as consequences of the poorer dental care which is typical in the young age. According to the National Health and Nutrition Estimates Survey (NHANES), in the US it is much more frequent in American whites, with a prevalence of 75%, than in African Americans and Hispanics, with a prevalence of 11% and 8% respectively. This might underline the influence of the genetic factors. No particular difference has been identified related to sex.

Malocclusion has proved to be very difficult to define as medical condition, because individual perceptions of what malocclusion is from a clinical perspective differ widely and because of the considerable disagreement among investigators regarding the results of epidemiological studies. Therefore, there is not generally accepted epidemiological index for the condition. Furthermore, is not an acute condition, and its treatment has been associated with a great degree of subjectivity.

As previously said, malocclusion is mostly an inherited condition, but can also be the consequence of the pressure exerted on the teeth because of particular habits and conditions, such as the use of pacifier, thumb sucking, tumors, or simply poor dental care. The disorder is also classified in three different categories based on the relative positions of upper and lower teeth: class I, II, and III. Class I is the most common, and it is characterized by an normal bite, although the upper teeth tend to slightly overlap the lower teeth. The class II is also called retrognathism or overbite, and is characterized by a more marked condition than that of class I, in which the upper jaw and teeth severely overlap the bottom ones. The class III, instead, is also known as prognathism or underbite, and is characterized by the opposite pathological condition: it is the lower jaw which protrudes forwards, causing the lower teeth to severely overlap the upper ones.

In many cases preventing malocclusion might be difficult, because as mentioned before this condition is often inherited from previous generations. In any case, prevention can be very effective if started during childhood, when due to the softness of the bones and the easiness in moving teeth the subject is much more prone to develop teeth misalignment. In particular, experts strongly recommend to avoid prolonged use of pacifier and prolonged bottle feeding, and to teach the child not to suck the thumb, all habits that might cause severe teeth misalignment and aberrant dental reshaping. It is also very important to try to detect malocclusion early, because treatment tends to be longer and more expensive as detection is delayed. If the condition is promptly treated, the clinical outcome of the treatment can be excellent.

The word “malocclusion” is a derivative of occlusion, the way in which opposing teeth on the two dental arches align themselves. Malocclusion literally means “incorrect occlusion”, indicating that the teeth are not align and their arrangement in relation to maxilla and mandible is inappropriate. The term was coined in the 19th century by Edward Angle, the famous American dentist widely regarded as the “father of modern orthodontics”. This condition is also known with other names like crowded teeth, crossbite, overbite, underbite, or open bit. In the most severe conditions, malocclusion might represent a serious medical problem, since teeth won’t be able to perform their function in a proper manner creating many serious health complications.

Malocclusion is defined as the misalignment of the teeth which becomes evident when maxilla and mandible approach each other and the teeth on the two dental arches clearly do not fit together. The word “malocclusion” is a derivative of occlusion, the way in which opposing teeth on the two dental arches align themselves. Malocclusion literally means “incorrect occlusion”, indicating that the teeth are not align and their arrangement in relation to the jaw is inappropriate. The term was coined in the 19th century by Edward Angle, the famous American dentist widely regarded as the “father of modern orthodontics”.

Malocclusion is usually an inherited condition passed down from generation to generation. However, the shape, position, and structure of teeth might also change as a consequence of pressures frequently exerted on them by several stimuli. These include prolonged use of bottle feeding and thumb sucking in early childhood, as well as the use of pacifiers after the age of 3. The medical conditions include injuries, tumors of the mouth and jaw, disorders of deglutition and poor dental care.

The severity of the signs of malocclusion vary based on the severity. Anyway, the typical sign is the evident misalignment of the teeth. Other major signs include the possible alteration of the features of the face, a frequent biting of the inner cheeks and tongue, and the consequent discomfort while chewing or biting. In the most severe cases subjects might even experience speech problems, like the development of a lisp, as well as the tendency to breathe through the mouth rather than the nose.

Malocclusion has been classified in three major classes: Class I, when the upper teeth slightly overlap the lower ones, Class II, when the upper teeth severely overlap the lower ones, and Class III, when it’s the lower teeth and jaw to severely overlap the upper ones.

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8. Björk A, Helm S. Prediction of the Age of Maximum Puberal Growth in Body Height. Angle Orthod. 1967 37 (2): 134–143. 
9. Wellington M, Hall CB. Pacifier as a risk factor for acute otitis media. Pediatrics. 2002 109 (2): 351–352. 
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