Ordodontics

Orthodontics is the branch of dentistry that deals with malocclusions, dental malpositions, suggesting the most suitable therapeutic means for correcting any anomalies present. The orthodontist is the specialist who usually treats children using dental braces. Before starting orthodontic therapy, the specialist must prepare the cephalometric study, which is obtained from the analysis of the radiographs (tele cranium inn lateral and orthopanoramic projection) and dental models. Very often the orthodontist and the surgeon collaborate for the resolution of more complex cases in adults.

Malocclusions

Malocclusion can be defined, in a simplistic way, as an incorrect match between the dental elements of the two arches. Normally there should be a certain uniformity in the relations between the two arches which leads to a consequent harmony in the whole maxillofacial complex. To be more precise, malocclusion does not concern only the teeth but a much more complex set of structures, in which the teeth represent only the element of greatest clinical evidence. In fact, malocclusion also involves the skeletal complex of the facial massif and the neuromuscular system. Abnormalities found in the mouth are often the result of an upstream problem. In fact, it is not uncommon to find a normal match of the arches but still have problems at the muscular level, for example.

Malocclusions can be divided into three classes: I, II, and III class. The classes are defined based on the ratio between the first permanent molars (according to Angle): the mesio-buccal cusp of the first upper molar occludes in the mesial fossa of the first lower molar; furthermore, the cusp of the upper canine is located between the canine and the first lower premolar. All this establishes a correct occlusion and is also defined as I class of Angle.

Class II malocclusion

Class II malocclusion occurs when the upper molar is half the cusp forward of the lower molar. In this case we speak of prognathism, and the upper jaw is considerably more advanced than the mandible.

Class III malocclusion

Class III malocclusion occurs when the upper molar is half cusp behind the lower one and in this case, we speak of lower jaw prognathism, and the mandible is considerably more advanced than the upper jaw.

Causes

The causes of malocclusions are often hereditary and therefore there is a genetic component in the anomaly. However, in some patients, the cause is not genetic, but linked to incorrect behavioral attitudes or other pathologies:

• Poor habits (such as finger and pacifier sucking which will be discussed later)
• Unsuccessful dental procedures such as dental fillings, prosthetic crowns and dental implants
• Loss of one or more permanent teeth
• Severely damaged teeth (chipped and not reconstructed)
• Tumors of the mouth and jaw
• Mandibular fracture in childhood
• Other rare cases (rheumatoid arthritis)

Bad habits

Children are often subject to occlusion problems. Often the malocclusions are to be attributed to habits, “normal” in the first years of life, but, if they continue beyond a certain age limit, they become “spoiled” and therefore harmful to the health of the mouth. The main bad habits are represented by the sucking of the finger and the pacifier. There habits are normal but only in the first years of child’s life. The pacifier should be removed at the maximum age of 3 years. The pacifier, and even worse, the finger, can cause important malocclusions. When the child sucks his finger, pressure develops in the palate which causes a reduced development of the upper jaw in a transverse direction, resulting in a narrow and high palate (due to the shape of the finger). This also leads to a reduced development of the nasal floor and therefore oral breathing (which is pathological).

Furthermore, the finger causes a reduced development of the muscles of the lips and therefore the latter are “incomponent”, in the sense that, at rest, they do not match each other. This can be followed by dryness of the gums which are therefore more susceptible to gingivitis. At the dental level it follows a malocclusion characterized by cross bite (since the maxilla is narrower than the mandible) and often dental crowding. In addition, the anterior teeth are displaced outwards (vestibularized) and therefore there is also an open bite.

Signs and symptoms

Dental malocclusion does not always manifest itself with the same signs. Let’s list some of them:

• Discrepancy between the dimensions of the two arches
• Upper jaw too narrow in relation to the mandible (the so-called “reverse bite”)
• Dental crowding
• Upper jaw very advanced compared to the mandible or vice versa

The symptoms can be multiple and involve not only the jaw but also the extra mandibular sites and even the spine:

• Difficulty when chewing
• Face with evident asymmetries
• Increased risk of caries and periodontal pathologies (often due to incorrect alignment of the teeth and therefore excessive accumulation of plaque difficult to remove by the patient with normal oral hygiene maneuvers)
• Problems with the temporomandibular joint
• Abnormal breathing (typically with an open mouth)
• Tinnitus, dizziness and ear pain (often attributable to joint problems)
• Breathing difficulties (rhinosinusitis, chronic cough, asthma and chronic bronchitis)
• Spinal symptoms (back pain)
• Gastro-oesophageal reflux disease (rare)
• Language difficulties (rare)

Diagnosis

Diagnosis in orthodontics is essentially based on a clinical evaluation and the execution of specific radiographic examinations. Often the malocclusions are not evident so the dentist will diagnose them during the first visit.

The clinical examination is based on the execution of certain mandibular movements with the help of the dentist who will perform various types of mandibular excursions: closing the arches to examine the type of bite, lateral movements of the mandible. Very useful is an examination of the patient’s face which can highlight relevant aspects.

The radiographic examinations that are normally requested consist of telecranium or cephalometry in the lateral-lateral and, sometimes, postero-anterior position. From the study of these radiographs (we speak of a cephalometric study) the professional can highlight the malocclusion in all its aspects. The cephalometric study is based on the detection of a series of lengths and angles formed by different structures of the craniofacial mass. Based on the values ​​of these measures it is possible to classify the type of malocclusion and the severity.

Another useful element for the diagnosis consists in the study of the plaster models in which the doctor can evaluate the type of closure, the presence of reverse, deep bite, crowding, available space etc.

Finally, notice that only a very small percentage of subjects have perfect occlusion. However, the patient often presents with mild malocclusions that often go unnoticed since symptoms are absent.

Therapy

Malocclusion therapy can be of various types based on the patient’s age and the severity of the malocclusion itself:

• Orthodontic: generally in children, using removable functional equipment. If fact, children are patients in the growth phase and therefore also the mandibular skeletal structures are constantly changing. In these cases, it is easier to intervene because, through a functional device, it is possible to guide the growth of the mandible or upper jaw according to our needs. This however is not possible in the adult patient (already after 12 years in women and 14 years in males) as the skeleton is fully formed and functional appliances will not have major effects on malocclusion. The functional appliances are made of metal with resin parts. They are defined functional as they simulate the muscles of the mouth to “work” in a certain way. In fact, the muscles have a fundamental importance in the development of the jaw bones during growth because they act thousands of times a day on the teeth and therefore can influence the development of the jaws. Moreover, thanks to the presence of strategically placed metal parts, they can solve even the possible bad habits (such as finger sucking). In fact, there is typically a metal barrier that prevents the child from interposing the finger between the arches. In subjects the child from interposing the finger between the arches. In subjects at the end of growth, the usefulness of functional appliances if practically nil as the bone components are now fully formed. In this case, a fixed orthodontic therapy is more suitable, which will be chosen according to the malocclusion present. The typical fixed appliance is made up of various metal components: the brackets are the so-called “stars” that are glued to the tooth in specific positions; the orthodontic floss that is passed through the brackets and provides the necessary force to move the teeth; the rubber bands, which are sometimes added to obtain movements. In addition to metal brackets, there are also ceramic ones that are white and therefore more aesthetically pleasing. There are also braces that are placed lingually on the teeth so that they are not visible, but his option is typically used for content purposes. In fact, at the end of therapy, to maintain the results obtained, it is advisable to resort to lingual restraint for a certain period, to avoid any recurrence. Finally, there is a latest generation device called Invisalign® and characterized by being practically invisible. It is a series of transparent masks that are worn on the arches and are replaced every two weeks (generally the orthodontist gives the patient a mask so that after two weeks he replaces it independently. The appointments generally take place on a monthly basis). The treatment begins with the taking of the impressions of the arches which are subsequently sent to the United States and from which a treatment plans is drawn up that will be subjected to the vision of the dentist. The dentist, using special software, displays the number of masks necessary to achieve the final goal, and the various movements that are obtained with each individual mask. This will be explained to the patient who will then be free to accept or refuse the treatment. The masks must be worn about 20 hours a day and removed only during meals or for special events (a party, etc.). For a safe result, it is essential that the patient wear the aligners for the time recommended by the dentist. The duration of the therapy varies according to the type of malocclusion. From 6 months to 2 years. The enormous advantage of this method line in the fact that the device is practically invisible when compared with the traditional fixed one.
• Surgical: in some selected cases (especially in malocclusions of genetic origin), simple traditional orthodontic therapy is not sufficient to solve the malocclusion problem. For this reason, maxillofacial surgery is used in order to restore the correct relationship between the two maxillaries. Sometimes, however, the surgery is done for strategic purposes. Basically, some elements are extracted (especially the wisdom teeth) in order to gain the necessary space for aligning the teeth.
• Myofunctional: it is a re-educational type of therapy that is often recommended to children to solve certain spoiled habits. It consists of a series of exercises which are explained to the patient and which he must reproduce daily at home for a certain period. By doing so, a re-education of the musculature that acts on the arches is obtained, which makes orthodontic therapy easier.