In broad terms, the orthodontic treatmentcan be categorized in following three categories:
Corrective orthodontics is the finished product of orthodontics. In this phase of orthodontics, the malocclusion is corrected and the teeth are placed into the best position. A number of different removable and fixed appliances can be utilized in corrective orthodontics. Surgery might also be necessary in total comprehensive corrective orthodontic treatment.
ANGLE’S CLASSIFICATION OF OCCLUSION
Occlusion, as defined by Webster’s dictionary, is “the bringing of the opposing surfaces of the teeth of the two jaws into contact.” A good occlusion refers to teeth aligned in a functionally and esthetically acceptable position to one another, to their respective jawbones, to the opposing dentition, and to the face.
In the ideal occlusion the teeth will not only esthetically acceptable, but will also be efficient in their work of tearing, chewing, and grinding food. In a patient with a malocclusion, the esthetics, function, and efficiency are diminished.
In the early 1900s, DL Edward H. Angle, the father of orthodontics, classified the malocclusion into different categories. His system of classification, known as Angle’s Classification, is still used in modem orthodontics. This system of classification is based on the anterio-posterior or sagittal relationships of the teeth to one another.
The Angle Classification is determined by the relationship of the mesiobuccal cusp of the maxillary 1st molar to the buccal groove of the mandibular 1st molar. Angle’s three classifications of occlusions are as follows:
Class I: Neutroclusion
This class of occlusion indicates the ideal occlusion, where no corrective orthodontic treatment is indicated. When the teeth are in a Class I occlusion, the front teeth generally assume a position of normalcy and the chewing and biting forces can be aligned appropriately, so that the teeth work in an efficient manner
The teeth can usually line up very nicely in a Class I occlusion depending on the size of the teeth and jaws, so the smile appears esthetically pleasing from both the facial and profile views.
Another name for Class I is neutroclusion. In a Class I or neutroclusion, the mesio-buccal cusp of the maxillary permanent 1st molar fits into the buccal groove of the mandibular permanent 1st molar.
Class II: Distoclusion
In persons with Class II or distoclusion, the lower jaw is positioned too far behind the upper jaw. The buccal groove of the lower molar is distal to the mesio-buccal cusp of the upper first molar. The upper incisors are usually displaced in front of the lower incisors.
A Class II type of malocclusion has two divisions:
Class I!, Division One
It is a malocclusion in which all the incisors are flared facially, that is, all of the incisors are forward and ahead of the lower incisors.
Class II, Division Two
In this division of class II the lateral incisors are displaced facially similar as in Division One, but the central incisors are not displaced facially. They are usually inclined downward and slightly backwards.
Correction in the Class II type of malocclusion is aimed at bringing the lower jaw forward and/or the upper jaw back to achieve a more harmonious Class I molar relationship.
Class III: Mesio-occlusion
In the Class III malocclusion the lower jaw is displaced labially in comparison to the upper jaw; the buccal groove on the lower molar is mesial of the mesio-buccal cusp of the upper first molar. Sometimes these patients have a crossbite of the anterior teeth with the lower incisors ahead of the upper incisors.
Orthodontic treatment for the Class III malocclusions is aimed at bringing the lower jaw back and moving the upper jaw forward. To correct severe discrepancies of this nature may require a combined effort of orthodontics along with orthodontic surgery.
DIAGNOSTIC AIDS USED IN ORTHODONTICS
Study casts are used for the diagnosis of the patient, and as a permanent record of the condition of the patient prior to orthodontic treatment. They are an important reference point throughout treatment and in the design of the final retention appliance. They are also useful in assessing changes as the patient’s orthodontic treatment progresses.
Good photographs are an important part of the patient’s initial records and are often taken throughout treatment. Photographs are also part of the final records. These are taken after the braces are removed and orthodontic treatment is complete. The extraoral photographs consist of facial views and a profile view.