I remember reading the definition of a facebow many times both in dental school and in graduate school. The definition was actually very confusing and it always took me awhile before I can see it in my mind how this piece of caliper works in the head and in the mouth. Then almost always people question the relevance of learning about this instrument when the majority of dentists do not use it in private practice.
Even amongst dental educators, we argue whether we should teach about this instrument at all in dental school. And students joke about how there is no scientific evidence to support the use of facebow in complete dentures.
For me, I completed most of my dental training after the days of strong gnathological influence. So while I learned about fully adjustable articulators, and learned about pantographic tracing, I used these instruments sparingly. I did one full mouth rehab using these instruments for my board case during graduate school. That was it.
So do I use facebow and fully adjustable articulators? Not always. But I do take them out when I know I need them. Or I understand enough the limitation of my own everyday dental instruments and know how to counteract the errors to ensure a favorable outcome.
I think the value of learning facebow is it helps students understand mandibular movement and how articulators work to simulate these movements and what errors can be expected from these instruments.
And I think the biggest value in understanding facebow is how it can affect the aesthetic outcome of your anterior restorations.
This is a patient who came to me in complete distress because she knew she was going to lose one of her front tooth. She had these two anterior crowns many years ago and never liked them. But she was so traumatized from the experience she decided not to seek further care. Until, one of them has fractured and deemed non restorable. And that was how she ended up in my office
When you look at her anterior teeth, you can see many of the imperfections. To name a few, the width to height ratio was not ideal and the gingival architecture was uneven and lacks symmetry. But one of the thing that really stood out was the midline orientation that was canted compared to her overall facial midline. This was probably the biggest eye sore to the patient but she just didn’t know how to communicate that to the dentist. She recalled that she had no temporary crowns and she was left very embarrassed with her teeth. When she tried the crowns in, she hated them but it was better than no teeth.
So when I saw those crowns, I knew that there was an inadequate information transferred to the lab. This would be a case where the facebow would have been beneficial. Or at least what I would have done is to work out the aesthetic parameters in my provisional crowns to determine where the incisal edges should be and the midline orientation and then to use that information to communicate with the lab.
If you treated this like regular crown restoration, the lab does not have the face or the lips to gauge how the midline should be. The models may have been arbitrarily mounted. The lab did not know the midline was canted, because to them it was perfect on their mounting. So the value of facebow transfer is to ensure you can relate the patient’s dental midline properly to the articulator. I hope you find this post useful. Thanks for reading.