In an ideal case, when we close our mouth, the upper teeth fit just over the lower teeth and the pointed ends of the molars in the upper jaw sit comfortably in the grooves of the molars in the lower jaw. The term “occlusion” refers to the teeth alignment pattern on the two dental arches or jaws – the upper and the lower, and the way these two arches close relative to one another. Malocclusion is therefore, any deviation from the normally accepted blocking i.e. mal-alignment of teeth in either or both jaws. A proper alignment is necessary in order to ensure a comfortable bite and also an aesthetic appeal of the dentition.
Types of Malocculsion
Malocclusion is classified in terms of the severity of the misalignment and the position of teeth. This term was coined by Edward Angle who is considered the “Father of Modern Orthodontics”. He grouped the dentitions into mainly 3 types under “Angle’s classification” based on the position of the maxillary first molar located away from the midline of the face. According to him, the pointed ends of the first molar of the upper jaw should fit in perfectly into the groove of the lower molar. Both the upper and the lower jaw have a smooth occlusion line where all the teeth are arranged. Any variation for this occlusion line can lead to malocclusion of the teeth. According to the angle, the left and right side of the jaw can display different patterns of malocclusion.
The three types of malocclusion are:
Class 1: Neutroclussion: In this condition, the bite is perfectly normal but the upper jaw overlaps the lower jaw slightly. The ideal molar alignment, as determined by the angle, is maintained but the remaining teeth may display spacing, crowding, over eruption or under eruption.
Class 2: Distocclusion: This condition is also known as retrognathism or overjet. In this condition, the points of the molars on the upper jaw are placed slightly anterior to the grooves on the molars of the lower jaw, leading to severe overlapping of the two arches. This condition can be further divided into two sub classes:
- Class 2: Division 1: In this division, the molars display the typical class 2 pattern and the anterior teeth tend to protrude.
- Class 2: Division 2: In this division, class 2 molar alignment is combined with a slight backward tipping of the central teeth and the lateral teeth overlap them.
Class 3: Mesiocclusion: This condition is called prognathism or more commonly as negative overjet. In this case, the points of the upper molar teeth are placed anterior to the grooves of the molars in the lower jaw. The lower front teeth tend to jut out and are more prominent than the upper front teeth.