The Beauty of the Custom Incisal Guide Table

In my most recent articles, I've been going over how to treat patients with failed dentition due to pathway wear. As clinicians it's important to know what to look for and how create a functional and esthetic solution for our patients that display this type of wear.

The patient you see in the main image is a dentist who was previously restored with veneers from #7 - 10. If you look at the second photo, you'll notice what appears to be large palatal wear facets. What is interesting to note is that this wear was not present pre-treatment but was created by the clinician that placed the restorations as a way to address the fact that the patient kept breaking his veneers.

Since the restorations had been placed, the right lateral had come off six times, and out of those six times the veneer had fractured a total of three times. The left lateral had fractured twice, was then converted to a crown, which subsequently fractured as well. His dentist saw the restorations fracturing and kept removing tooth structure on the palatal to help prevent the patient from continually breaking the next restoration.

But was that logical?

Think about it this way: the teeth were restored with veneers. So, if the palatal tooth surface wasn't changed and the ceramic is breaking, altering the palatal concavity will not solve the problem because it wasn't changed in the first place. The only change that happened was the lengthening of the teeth, which disrupted the patient's ability to get back to his "previous" end-to-end position.

If you look at the nature of the facets on the facial of the lower anteriors, you'll notice that they are both angled vertically towards the facial surface and there are flattened areas on the edges of the teeth. Since this patient was treated with veneers, the pathway isn't the culprit, it's the ability to enter / exit the pathway and get to the ends of the teeth. In order to treat this patient, he needs to have the "overbite" addressed not the pathway (because the pathway essentially wasn't altered). To decrease the overbite there are three options: shorten the lower incisors, shorten the upper incisors, or open the VDO.

Assuming that the maxillary incisal edges were lengthened to improve the esthetics, we probably don't want to shorten them. When looking at his lower arch, you'll notice the anterior incisal plane is stepped up above the posterior occlusal plane. Given this finding, the correct treatment option to help prevent further fracture is the either level the lower incisors with the posterior occlusal plane (by orthodontic intrusion or simply by plasty of the incisal edges with a bur) OR restore the lower posteriors and raise the occlusal plane to be level with the current lower incisor position. Although the use of a custom incisal guide table will tell you the amount the anterior relationship needs to be altered, essentially what it comes down to is however much length was added to the incisal edges of the maxillary anterior were restored, the lower incisal edge position will need to be moved apically by the same amount.