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Edentulism

author icon By Dr. George Ghidrai

Edentulism is a medical condition characterized by the absence of one or more teeth. This medical condition is caused by loss of teeth.

Classification

Following teeth loss, several edentulous gaps will form on the dental arches. The length and disposition of each gap can give important information about the type of prosthesis that may be used to restore the missing teeth.

Each prosthetic restoration has certain indications and it cannot be utilized in every clinical circumstance. Therefore, only certain types of edentulism are suitable for a dental bridge restoration.

Edentulism is divided into two major classes :


  1. Complete edentulism

    complete edentulism

    complete edentulism

    All teeth from a dental arch are missing. This particular class cannot be restored with traditional dental bridges.

    Types of prosthetic devices that are indicated :

    • Complete removable dentures (full dentures)
    • Dental implants supported dentures (fixed or removable)


  2. Partial edentulism

    One or more teeth are missing but never all. Only certain forms of partial edentulism can be treated with traditional dental bridges.

    Let's see how this condition is classified based on the number of missing teeth and the disposition of the edentulous gaps.


Classification of partial edentulism

Over the years, a large variety of classifications has been proposed. One of the most familiar classifications belongs to Dr. Edward Kennedy. The classification is very simple and can be an important asset in designing dental restorations.

Depending on the position and extent of edentulous breaches, Kennedy divided partial edentulism into 4 classes.

Kennedy Class 1

Bilateral edentulous areas located posterior to the remaining natural teeth.

Back teeth on both sides of the dental arch are missing. The condition is caused by the early loss of molars and / or premolars on both sides of the dental arch.

edentulism classification : kennedy class 1

It is very difficult to restore this class with traditional dental bridges.

Types of prosthetic devices that can be used

  • Fixed or removable restorations supported by dental implants
  • Removable partial dentures

Kennedy Class 2

Unilateral edentulous area located posterior to the remaining natural teeth.

Posterior teeth on just one side of the dental arch are missing. This condition is consequent to the early loss of molars and / or premolars on one side of the dental arch.

edentulism classification : kennedy class 2

This class is the most difficult to treat. Cantilever bridges have a very poor prognosis. Removable partial dentures are difficult to design. Implant supported reconstructions seem to be by far the best option.

Types of prosthetic devices that are indicated

  • Fixed or removable restorations supported by dental implants
  • Removable partial dentures although they are difficult to design
  • Cantilever bridges only in limited circumstances

Kennedy Class 3

Unilateral edentulous area with natural teeth both anterior and posterior to the area

Posterior teeth are missing (molars and/or premolars) but there are teeth on both sides of the toothless gap.

edentulism classification : kennedy class 3

This class is very suitable for a dental bridge restoration if the breach is not overextended. Dental implants can be successfully used even if the gap is overextended.

Types of prosthetic devices that can be utilized

  • Fixed dental bridges supported by natural teeth
  • Fixed dental bridges supported by implants
  • If the gap is overextended, partial removable dentures supported by implants or natural teeth

Kennedy Class 4

A single but bilateral (crossing the midline) edentulous area located to the anterior of the remaining natural teeth.

Anterior teeth are missing (incisors) and the edentulous gap passes on both sides of the midline. In these situations, aesthetics is the most important factor.

edentulism classification : kennedy class 3

This particular class is also suitable for a dental bridge restoration. Because of the high aesthetic demands, the use of porcelain or zirconium bridges is highly recommended. Bridges supported by dental implants are excellent solutions as well.

Types of prosthetic devices that are indicated

  • Fixed dental bridges supported by natural teeth
  • Fixed dental bridges supported by implants
  • Removable partial dentures in certain situations

Combined Classes

Obviously, in the everyday practice many clinical situations are various combinations between the 4 classes. This means that there are more edentulous gaps, without a standard disposition.

edentulism classification : kennedy combined class

In the picture above we have a combination of Kennedy classes 2 and 3.

In these cases, the first question is how to restore the most difficult gap. This gap belongs to the class with the lowest number.

The best approach is to design a prosthetic device that restores both gaps (even if it has 2 distinct parts). It is pointless to design, for example, just a dental bridge that restores the class 3 gap, hence leaving the posterior breach untreated.

In this particular situation, reconstructions supported by dental implants or removable partial dentures are the best options available.


Conclusions

  • A traditional dental bridge is difficult to design if the back (or posterior) tooth is missing.

  • Kennedy classes 3 and 4 are the most suitable for dental bridge restorations.

  • Implant supported restorations can be used in almost any type of edentulism.


Edentulism classification is just one of the criteria used in designing dental bridges. It is, however, a very important one.

Last review and update: May 2019



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