Edges of anterior teeth are chipped and broken on a regular basis. They are broken during playground accidents, chipped while drinking from a glass or bottle, or biting hard into a fork or the pit of a plumb. Notches are created from habits like pipe smoking, sewing-needle holding and fingernail biting. The edges in Fig. 1 could easily be the result of any of these. The long-term predictability of restoring them is directly related to understanding the etiology. There is no need to restore the edge of a fingernail biter or needle-holder if the habits are not changed (assuming that the goal is actually long-term success).
But what about chipped or worn teeth created by parafunctional habits? Rough edges rubbing on other rough edges can result in more chipping or irregular and uneven wear until they fit together like uneven jigsaw puzzle pieces. Rough edges rubbing on smooth edges can do the same (Fig. 2).
After ruling out external habits like nail biting or needle-holding, and identifying the specific movements or habits that have seemingly lead to the breakdown (Fig. 3), we have an opportunity to create natural looking teeth with improved function.
In other words, if we take the time to create smooth edges on smooth edges that are level, with even and broad contact to spread the load, our odds of long-term success increase dramatically (Fig. 4,5 and 6).
We can even go to the extreme to put the odds in our favor and create a template of the final result, visualizing the end before we begin (Fig. 7). What could go wrong now? Right?
You might even go so far as to say to yourself, "My patient is so lucky that she found me, the Sherlock Holmes of dentistry. I have solved the crime and fixed it for good." But two weeks later when the patient calls the office to say that part of my new creation of beauty and function has chipped (Fig. 8: distal incisal edge of tooth #9), I want to call in sick or hide under my desk. What could have happened?
I didn't know what to do or what I would say, but I walked into the operatory with my tail between my legs, ready to take my medicine. She then said in a loud, aggressive and excitable voice, "I know how it happened!" Oh geez, here it comes, this is going to hurt. "I know what I do and when I do it!"
What (and when) who does? What she does? I forgot they were her teeth, not mine. Let's see where this is going. "When I'm driving, especially in traffic and in a hurry, I move my jaw way over to this side and forward and lock my teeth in like this (Fig. 9)."
When we can't solve a dental puzzle, it makes sense to ask our patients to pay attention to what they do with their teeth during the day and wonder with them what they might be doing when sleeping. But when we think we have solved the puzzle, it might also make sense to ask our patients to pay attention to what they do with their teeth.