Communicating a Facebow Transfer Procedure: A Case Study

Accurate facebow transfer procedures provide the spatial component to achieve esthetic and functional success. This success is weighted heavily by the finished product from the dental lab. The dental lab is a key partner in creating the beautiful and accurate outcomes of our indirect restorations. This requires concise and open communication throughout the process.

In addition to concise communication with the lab, it is also important to provide a precise transfer of functional information to accomplish the goals of the case.

This includes:

• correct models and impressions
• impeccable photography
• on-target representation of spatial relationships

Case Study of a Successful Facebow Transfer Procedure

The purpose of the facebow is to transfer the spatial relationship of the patient's maxillary arch to the articulator. One of the great restorative dentists, Dr. Peter Dawson said that “the casts must have the same relationship to the horizontal axis of the articulator that the dental arches have to the cranial condylar axis.”

Translating this to the dental lab is the first step in this process. Technicians utilize the articulator as a tool to establish the occlusal and incisal planes in reference to “the benchtop.”  The “benchtop” is the reference to horizon. The importance of level planes is critical to an esthetic success. A deviation of only one degree can be easily noticed, even in casual observation. Developing and accurately utilizing a technique to verify horizontal planes is key in communicating with the dental laboratory.

Taking an Ugly Duckling or Venetian Plane Image

Using the “ugly duckling photograph” is the most common facebow transfer procedure. The image above is representative of this process. To take a successful photo with your digital camera, have the patient standing and holding lip retractors. This allows for simultaneous vision of both the pupils and maxillary incisal/occlusal planes. Make sure the camera is oriented so that the lens is aiming directly at the incisal embrasures at the level of the incisal/occlusal plane.

Looking at this image, you should be able to view the orientation of the maxillary arch relative to horizon. In the example image, the patient is standing in front of venetian blinds allowing the blinds to function as a level reference point. This aids in the orientation evaluation. However, the “venetian plane” is not mandatory. If the patient is standing upright, with their shoulders against a wall, the head is in a vertically correct position. Properly composing this image provides necessary information to the dental laboratory for cross-referencing the orientation of the facebow.

This horizontal verification technique is not new, but it is effective. Dr. Bob Winter of Spear Faculty, has taught and emphasized the importance of this this strategy for years. He has written about and incorporates this procedure into his workshop presentations. This strategy and course of action has also been a part of my case workup for years due to his teachings.

Part of my regular restorative process includes reviewing the relevance and importance of including this technique. The example images in this case study came from a recent case in which the facebow transfer did not accurately represent the incisal/occlusal plane of the patient. If it had not been for the “ugly duckling” image, and my open communication with the lab regarding the canted plane, the final case may have been an esthetic and functional disaster.

Case Study: Andy's Pretreatment Image

During my work with my patient Andy, I found examples that apply to the importance of facebow treatment process and how important lab communication is. Andy presented as a complex tooth wear case. During our discussion, I learned that he expected to improve his smile appearance by increasing his tooth length. The issues with his smile developed from a parafunctional edge-to edge tooth positioning habit. The treatment plan I developed included orthodontic intrusion of the upper and lower teeth and leveling of the occlusal planes. Following orthodontics, we would proceed with restorative treatment of the upper and lower teeth.

Case Study: Post Orthodontic Treatment

Once the orthodontics part of the treatment plan was complete, the first phase of the restoration of the upper arch began. Orthodontics leveled the gingival tissues and flattened the occlusal planes. We created a diagnostic wax-up as a guide to esthetic and functional tooth contour and position. Subsequently, the upper teeth were prepared for ceramic veneers to improve contour and widen buccal corridors.

Following the final impression of the tooth preparations, we placed provisionals and adjusted the occlusion to accommodate the functional patterns necessitated by the case. Alginate capture of the corrected provisionals preceded the facebow transfer procedure of the same. Before releasing the patient, we took a series of provisional photographs. We included the “ugly duckling” image as part of that series.

Next, we prep the appropriate models, impressions, bite records and photographs in the mailing box for transfer. The facebow transfer jig is “securely” wrapped and gently placed in the box and mailed to the dental lab.

Mounted Models and the Importance of the “Ugly Duckling” Image

When the case was received by the dental lab, the included components were removed, and the models were mounted to the semi-adjustable articulator by using the bite records and facebow mounting jig. Upon review of the photographs, the dental lab technician noticed the discrepancy that existed between the mounted models and the “ugly duckling” photograph. This disparity prompted a call from the lab technician to notify me (and my lab assisting team) of the difference between the mounting and the photographic image. An alteration had occurred in the facebow transfer jig which resulted in this difference. Following a discussion, we made the decision to re-mount the models to correspond to the incisal/occlusal plane observed in the “ugly duckling” photograph.

The “lips retracted” portrait photograph was crucial for verifying the plane of occlusion and ultimate restorative outcome. As careful as our dental assisting teams may be with packaging and shipping cases to the dental labs, it always remains a possibility that something can shift in transit. As in Andy's complex case, this “ugly duckling” photograph becomes a key component for reference to the true positioning of the incisal edges. Accuracy in the facebow transfer procedure and open communication with the dental lab can make the difference between a successful outcome or a frustrating and costly remake.

Jeffrey Bonk, D.D.S., is a member of Spear Resident Faculty.