Head and Neck Anatomy
The Three Stages of Malocclusion
Occlusion is defined as being the relationship of the maxillary and mandibular teeth during functional contact. In more simplistic terms, occlusion is where the teeth are aligned and fit together. Ideally, the maxillary teeth fit slightly over the mandibular. Very few people have perfect occlusion. Any deviation from perfect occlusion is called malocclusion. Since so few people have perfect occlusion, malocclusion is divided into three classes. These classifications are based on Angle’s classification system developed by Dr. Edward H. Angle. The system describes and classifies occlusion and malocclusion. The basis of this system is that the permanent maxillary first molar is the key to occlusion, assuming that the patient is occluding in centric position. Centric position is when the jaws are closed with the maximum stable contact between the maxillary and mandibular teeth. Malocclusion, itself, is defined as an abnormal positional relationship of the teeth. Malocclusion can affect the teeth, joint and muscles of the head and neck. It is often hereditary. A person can have a small jaw and large teeth or can have a large jaw with small teeth. Thumb sucking and improper swallowing can also have an effect on occlusion in primary and permanent dentition. A person can also have subdivisions of malocclusion. A subdivision is a unilateral condition of the left or right side. Meaning, one can have multiple classes of malocclusion on the left side or right side. So, a patient could have class 1 occlusion on the left, but also have class 2 on the right. Class 1 Malocclusion
Class 1 occlusion, also known as neutrocclusion, is the ideal, or normal, occlusion. It is also the normal anteroposterior relationship of the jaws. The mesiobuccal cusp of the permanent maxillary first molar fits into the buccal groove of the permanent mandibular first...