Midline inclination isn't only noticed by dental professionals, anybody can notice an imperfect inclination even if it's as little as one millimeter off. With that said, in order for a smile to be esthetically pleasing, it must be perpendicular to the patient's interpupillary line or a level reference point in the room, such as the floor or a slat in window blinds. In order to achieve the most ideal result, you must know how to effectively communicate with your lab technician to avoid setting your patient up with a smile that's more canted than it was when they sat in your chair.
So, how do you go about communicating what angulation you need? In addition to photographs, the most predictable route is to utilize a facebow transfer to accurately transfer tooth position as it looks in the patient's face. That will help both you and the technician determine how to correct a flawed tooth position. Follow the steps below, and you'll succeed in effectively communicating exactly what your patient needs to the lab technician.
Step 1: A lab technician always has a better chance of producing what you need if there is a reference point. Mounting your models on a semi-adjustable articulator will ensure that the any corrections to the midline are perpendicular to lab bench. The lab bench works as the same reference indicator as the one you used to set up the facebow (floor or slat in blinds)
Step 2: Prep your patient with the facebow. The way you position it on their face can ultimately alter the midline you get back from your technician. Make sure the earbow is inserted into the ear as far as it can comfortably go, ask you patient for help if necessary, they can “feel” how far it is in.
Step 3: If your patient's interpupillary line is perpendicular to the horizon or the floor you can use that line as a reference. However, some patients will have asymmetric heights to their eyes, which will force you to take a different approach. If this is the case, instead of using their pupillary line as a reference, have them stand, straighten their head and use the floor of the room, or a blind slat as your reference using a level attached to the articulator.
Step 4: Take digital facial photographs of the patient smiling and level the photos to either the patient's pupillary line or to a reference line on your computer. This not only will make it easier for you to compare your model to the patient's natural smile, but also creates another tool your lab technician can reference to avoid confusion.
If your lab technician uses your references and creates a model that is level with the lab bench, you and your patient will get exactly what you've asked for.