The Importance of Incisal and Occlusal Planes

To achieve the most ideal esthetic and functional outcome for the patient, the goal in virtually all dental therapies is to level the incisal and occlusal planes to horizon. Orthodontics, orthognathic surgery, periodontal procedures, full denture prosthodontics, and restorative therapies all use horizon as the standard reference.

Once the incisal plane is level the gingival heights can be adjusted accordingly, and the maxillary midline can be made perpendicular to this horizontal plane. Why is this so important? Because successful design of the occlusal scheme provides an esthetic result that is more visually pleasing, and enhances the patient's envelope of function. To accomplish this you must have an accurate means of transferring the existing condition of the patient to the articulator, generally through the use of an esthetically corrected facebow.

It is important that this information is captured and communicated to all appropriate members of the dental team. It is my strong recommendation that the procedures needed to capture this information are completed during the initial diagnosis and treatment planning phase, and again during the provisionalization stage. In my last article, I provided you with guidelines for composing a photograph, as discussed in my article: “My Favorite Photograph” that accurately portrays where the patient's planes are relative to horizon. Following those steps facilitates an accurate gathering of the necessary information.

In the laboratory, a facebow transfer is used to mount the maxillary cast. Freehand mounting can lead to an error in the occlusal plane and midline if a cant exists, because unless told otherwise, the technician will assume the planes are level. A photograph of the facebow is recommended and should be sent to the lab with your restorative case, to provide the technician with verification of the accuracy of the transfer.