Someone asked me the other day, “What is the most overlooked aspect of All-on-Four Dentures?”

By and large, I think the answer is lip support.

Too often, after hearing a patient say they want “permanent dentures” the case is hastily planned as an All-on-Four case. The implants are placed, the case is restored, and Viola!

But every so often, (especially if the case is not planned properly) a patient will end up with the appearance of a ‘sunken-in’ face and is not at all happy with the end result. Why?

I see many patients in this situation. They’ve already spent $50,000 at another clinic and are very unhappy with the results – so they come to me to see if I can fix it.

Just this upcoming week, I have a patient flying in from Arizona who had upper and lower All-on-Four done at one of those corporate implant centers. She was very unhappy because she want’s a fuller appearance, so she is flying to California to see me to have a new set of implant dentures made.

What This Article Will Teach You

Reading this article will help you understand to use lip ‘support’ as a diagnostic factor for implant dentures. After reading this, a little red flag should come up if you run into someone who is NOT a candidate for All-on-Four and I’ll explain some other possible options.

Sometimes the All-on-4 is the best treatment, other times it is not. Let’s run away from that cookie-cutter approach and instead, use a systematic examination for each patient.

So let’s dive in!

Lip support is the degree to which the tissues behind the lips provide backing (or support) so that the lips are properly ‘plumped’ and display esthetic facial contours. Fixed complete dentures (All-on-Four) can provide some support. However, in some cases, the patient is in need of more lip support than a fixed complete denture can provide.

In these instances, a removable prosthesis is recommended, instead. This is because a removable prosthesis can have a flange that extends into the sulcus that will plump-up the lip. 

Therefore, the amount of lip support required can determine whether the patient will be better treated by a fixed or removable prosthesis.

Bone Loss Over Time

If the absence of teeth, our jaw bones will shrink over time. As this bone loss progresses, the maxilla becomes narrower and shorter and the mandible becomes wider and shorter. (Pietrokovski et al 2007) Also, the crest of each alveolar ridge resorbs in such a way that the ridge appears to move posteriorly over time. 

This picture may serve to represent a patient who recently lost their teeth:

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This picture shows the pattern of bone loss in both arches.

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Bone resorption over time. The maxiilary ridge becomes narrower and shorter. The mandibular ridge becomes wider and shorter. Both resorb in a posterior fashion.

How to Classify Defects Caused by Bone Loss

A patient with a complete set of teeth has lip support provided by:

  1. the facial surface of the incisors
  2. the alveolar ridge.

Take a look at this next picture. The blue line in the figure represents the soft tissue facial profile:

IMG_4228

If all the teeth were missing, some lip support is lost and lips would curl inwards. When a patient is missing only their teeth and not any significant amount of surrounding alveolar bone, the patient can be said to possess a “tooth-only” defect.

This figure represents a tooth-only defect:

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As the alveolar bone remodels and resorbs over time, the patient will develop a composite defect. A composite defect is a clinical presentation in which a patient has lost some or all of the tissue volume previously occupied by their teeth, gums, and alveolar bone.

So, while in a tooth-only defect the patient has lost only their teeth, in a composite defect the patient has lost their teeth and some alveolar ridge volume.

A tooth-only defect usually progresses to a composite defect as the patient continues to lose tissue over their lifetime. A composite defect can become more severe over time especially in patients who utilize conventional dentures for many years.

A severe composite defect:

IMG_4227

 

Let’s take a look at these concepts on an actual patient.

Let’s call this patient Mary. Mary has an upper conventional denture and a lower fixed complete denture on five implants (You could call it an All-on-Five).

Take a moment to evaluate her pictures and determine what type of defect you think she has: tooth-only, moderate composite, or advanced composite?

Here she is with her upper denture in place:

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This is without her upper denture:

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Now for a side view. Here is a pic with her upper denture:

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And without her upper denture:

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Mary is an excellent example of a severe composite defect. With her upper denture out of her mouth, her upper lip completely collapses and the edge of her lip curls inwards.

Even though she has a fixed complete denture in her lower jaw, it is possible to see evidence of her composite defect here too. Notice the very deep “mentolabial sulcus” (the horizontal fold seen right above her chin in side-view).

The prominence of this sulcus could be softened by the flange of a removable prosthesis. However, because she has a fixed prosthesis, she displays what is sometimes referred to as a “witch’s chin”.

Mary’s chief concern was that her “permanent denture” was driving her crazy. She explained that her lower lip felt like it was “too pushed out” and “the little crease at my lower lip bothers me.”

This is one example in which a removable implant overdenture may have been a better choice.

If a patient with a severe composite defect is treated with a fixed complete denture, a big problem will be the prominent sulci that can be formed and the sunken-in appearance that will result.

The same thing can be encountered in the upper lip in which a sulci, called the nasolabial fold, can be unintentionally created. This nasolabial fold can be seen in the following pictures.

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For the following patient, I was able to actually eliminate the nasolabial fold just by rearranging the teeth on the existing metal bar.

IMG_4233 IMG_4236

The culprit behind it all can be seen in this next picture. If the patient has a severe composite defect, and they are treated with a fixed prosthesis, they will often end up with a “stair-step” between their prosthesis and their gums.

IMG_4231

On the other hand, this following picture shows a beautiful prosthesis that adapts closely with the patient’s gums:


 

Ok, so we’ve covered a lot of ground here. Here’s a brief recap:

  • In the absence teeth, the maxiilary ridge becomes narrower and shorter. The mandibular ridge becomes wider and shorter. Both resorb in a posterior fashion.
  • Lip support comes from the facial surface of the incisors and the alveolar ridge.
  • When a patient is missing only their teeth and not any significant amount of surrounding alveolar bone, the patient can be said to possess a “tooth-only” defect.
  • In a composite defect the patient has lost their teeth and some alveolar ridge volume.
  • If a patient with a severe composite defect is treated with a fixed prosthesis, this may result in a nasolabial sulcus in the upper jaw or a mentolabial sulcus in the lower jaw.

Subscribe to the blog (upper left on desktop, below on smartphone) to stay tuned for Part II of this article in which we will go over the restorative options for these patients and how to trouble-shoot these cases.

I hope this article was informative. If you learned something, leave a comment and let me know 🙂

Best,

Dr. Ivan Chicchon

ps. check out my cases on instagram! @implantninja

 

 

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