Human jaw moves around an axis that connects two points of the temporomandibular joint marked in red on left. Replicating the jaw hinge axis in a model, shown on the right, is crucial in prosthodontic treatments. / Courtesy of Kim Hyung-guen

By Kim Hyun-guen

Getting prosthodontic treatments such as dental implants or dentures is rarely a pleasant experience. Often, the device, or prosthesis, inserted into a patient’s mouth, causes discomfort due to inaccurate occlusion. This is when the top and lower parts of the mouth don’t close comfortably together.

This defective meeting of the upper and lower teeth can lead to numerous problems.

These measures are costly and time-consuming. Fortunately, focusing attention on the jaw hinge axis can improve the success rate of prosthdontic procedures.

This problem engages proshodontic dentists across the world. They specialize in the aesthetic restoration and replacement of teeth to restore optimum appearance. Specific procedures include implants, crowns and bridges, dentures, rehabilitation of occlusion and maxillofacial surgery.

All the prostheses are made in the laboratory. Thus, duplicating the patient’s mouth and accurate position of upper and lower teeth is a crucial yet nearly impossible task.

Consequently, treatments cause lots of stress and it takes time for both patients and doctors to remake the prosthesis again and again. This has driven the cost of such procedures well above other dental treatments.

Focusing on the alignment inaccuracy that occurs when a dentist is making casts of upper and lower teeth on an articulator can minimize the need for aggressive adjustments.

Often, dentists overlook the importance of replicating the jaw hinge axis. The human jaw moves around an axis that connects two points of the temporomandibular joint. A failure to mimic this natural pivot results in discomfort.

Practitioners can mirror the pivotal line by taking an interocclusal imprint when the patient’s mouth is closed. Connecting the impressions of the top and bottom teeth using this imprint can stabilize the model and ensure a better fit into a patient’s mouth.

This unique approach was presented at the John F. Johnston’s Advanced Prosthodontic Meeting in Indianapolis in the United States.

The writer is a U.S. dentist and prosthodontist who practices in Seoul. Kim is interested in problems that dentists around the world face daily.