Ideal occlusion: inter (between) arch relationship of teeth


Occlusion [ah KLOO zhun] in dentistry refers to the relationship of the upper and lower teeth when they close together or contact one another during function or rest. Therefore, occlusion involves the contacting of occlusal and incisal surfaces of opposing maxillary and mandibular teeth. The word occlude literally means to close up or shut, as in closing your teeth together.

It is important to learn the relationships of teeth in ideal occlusion in order to identify malocclusions that could contribute to dental problems. The importance of proper occlusion cannot be overestimated. It is essential for both dental health and general health and for a patient’s comfort and ability to speak, chew, and enjoy food. Understanding occlusion requires a knowledge not only of the relation of the lower jaw to the upper jaw but also of the jaw joints, their complexities, and the muscles, nerves, ligaments, and soft tissues that affect the position of the mandible. These topics will be covered in much more depth in Chapter 9. The arrangement of teeth within the dental arches (alignment, proximal contacts, and embrasure spaces) has been discussed in the previous section of this chapter, and the ideal relationship of the mandibular teeth to the maxillary teeth will be presented in this section.

Tooth relationships were described and classified as classes I, II, and III in the early 1900s by Edward H. Angle. He classified ideal occlusion as class I and defined it based on the relationship between the maxillary and mandibular dental arches. When defining class I occlusion, the teeth should be closed together in their maximum intercuspal position, or best fitting together of the teeth, as shown in Figure 1-58. This relationship can be achieved on handheld models when the maxillary teeth fit as tightly as possible against the mandibular teeth (i.e., are most stable). The following specific tooth relationships define class I ideal occlusion in the adult dentition:

A photo shows dental stone casts with both sets of adult teeth fitting together.

FIGURE 1-58. Dental stone casts with adult teeth fitting together in the maximum intercuspal position (tightest fit). Notice that, from this view, each tooth has the potential for contacting two opposing teeth except the maxillary third molar. The vertical red line marks the relationship of first molars in class I occlusion: the mesiobuccal cusp of the maxillary first molar occludes in the mesiobuccal groove of the mandibular first molar. Also, the maxillary canine fits into the facial embrasure between the mandibular canine and first premolar.


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Sep 12, 2021 | Posted by in General Dentistry | Comments Off on Ideal occlusion: inter (between) arch relationship of teeth
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