Leading and Trailing Edges: Part 2

How do you ensure aspects like pitch, bevel, crossover, and trailing edges are taken into account? Here, Dr. Green continues his commentary on this valuable aspect of dentistry.

A Flaw of Design: Why Leading & Trailing Edges Matter

While I was helping in the Pankey Scholar Program, the participants would video their patient during the post-case conversation. They would record the movements of the patient in protrusive, left, right radial lateral into crossover, and lateral protrusive.

As I was observing patients in the videos, I would occasionally notice a hesitation once they got to the tips of the cuspid. Sometimes there would also be a quiver of the jaw or muscle twitch. I would usually review the video later with the participant and look at the finished case on the articulator with them. We would talk about how they could put a ‘landing facet’ on cuspids too since they are anterior teeth.

They were beautiful porcelain cases, so I would show them on another set of models how easy it was to do. I told them they would know it was right when the patient’s eyes smiled and the hesitation and muscle twitching went away. Another benefit of a facet on a cuspid is that it is gentler on opposing incisal edges of centrals and laterals in all mandibular movements.

Talking About Edges

One way to talk about the leading and trailing edges: on upper anterior teeth, including cuspids, the leading bevel is at the lingual-incisal junction. The bevel develops naturally on natural teeth. With restorations, the dentist creates it.

The leading edge of the lower incisors, including cuspids, is on the facial incisal junction. It is created in natural teeth with normal function. When restorative material is used, it must be managed by the dentist.

The trailing edges and bevels (labial-incisal edge of upper anteriors plus cuspid and lingual-incisal edges of lower anteriors, including cuspids) are always shaping with function. This can lead to micro-fracturing or major sheering of enamel vertically. Therefore, the trailing edge bevel must always be managed by the dentist with intention. The goal should be preventive with natural tooth or any restorative material.

Once a natural tooth has been worn to the point of losing incisal embrasure, the medial and lingual marginal ridge convex Shaw on the lower can act like a chisel against the labial incisal edge of the upper. This is seen often in a crossover position.

Edges, bevels, and pitch may not be simple, but awareness comes in the doing and observing!

Richard Green DDS MBA

Richard Green DDS MBA

Rich Green, D.D.S., M.B.A. is the founder and Director Emeritus of The Pankey Institute Business Systems Development program. He retired from The Pankey Institute in 2004. He has created Evergreen Consulting Group, Inc. www.evergreenconsultinggroup.com, to continue his work encouraging and assisting dentists in making the personal choices that will shape their practices according to their personal vision of success to achieve their preferred future in dentistry. Rich Green received his dental degree from Northwestern University in 1966. He was a early colleague and student of Bob Barkley in Illinois. He had frequent contact with Bob Barkley because of his interest in the behavioral aspects of dentistry. Rich Green has been associated with The Pankey Institute since its inception, first as a student, then as a Visiting Faculty member beginning in 1974, and finally joining the Institute full time in 1994. While maintaining his practice in Hinsdale, IL, Rich Green became involved in the management aspects of dentistry and, in 1981, joined Selection Research Corporation (an affiliate of The Gallup Organization) as an associate. This relationship and his interest in management led to his graduation in 1992 with a Masters in Business Administration from the Keller Graduate School in Chicago.

One thought on “Leading and Trailing Edges: Part 2

  • Richard A. Green
    February 26, 2018 at 11:55 am

    Hi – I would a couple of “typos” on the Part II that if corrected would probably make more sense to the reader. When talking about Trailing Edges: they do “shape” with function, yet more importantly the trailing edges are “sharpening” with each stroke and the bevel must be reestablished by the dentist from time to time. Secondly, on lower incisors that have been worn and lost their incisal embrasure, the mesial and distal marginal ridge “shape” (instead of Shaw) is convex and can act as a chisel and fracture out a large piece of the upper anterior tooth on the labial aspect of its trailing edge. my “typo’s” – sorry!


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