Partially Edentulous Conditions

In cases where in the mouth teeth are missing, edentulous situations are grouped in 4 categories that were defined by Dr. Edward Kennedy in his classification of partially edentulous arches.

• Class I (bilateral free ended partially edentulous)
• Class II (unilateral free ended partially edentulous)
• Class III (unilateral bounded partially edentulous)
• Class IV (bilateral bounded anterior partially edentulous)

Kennedy Class I
This type is for people who are missing some or all of their teeth on both sides in a single arch and there are no teeth posterior to the edentulous area. Class I RPD´s clasp onto the teeth are more towrds the front of the mouth, while replacing the missing more back of the mouth teeth on both sides with false denture teeth.

Class II
RPD´s are fabricated for people who are missing some or all their posterior teeth on one side in a single arch, and there are no teeth behind the edentulous area. Thus, Class II RPD´s clasp onto teeth that are more towards the mouth, as well as on teeth that are more towards the back of the mouth of the side on which teeth are not missing, while replacing the missing more back of the mouth teeth on one side with false denture teeth.


Class III
RPD´s are fabricated for people who are missing some teeth such that the edentulous area has teeth remaining both posterior and anterior to it. Unlike Class I and Class II RPD´s which are both tooth and tissue borne, Class III RPD´s are strictly tooth borne, which means they only clasp onto teeth and do not need to rest on the tissue for added support. This makes Class III RPD´s exceedingly more secure as per the three rules of removable prostheses that will be mention later namely: support, stability and retention.

However is the edentulous area described in the previous paragraph crosses the anterior midline, the RPD is classified as a Class IV RPD. By definition, a Kennedy Class IV RPD design will posses only one edentulous area.

Classes I, II and III RPD´s that have multiple edentulous areas in which replacement teeth are being placed are further classified with modifications states that were defined by Oliver C. Applegate. Kennedy classification is governed by the most posterior edentulous are that is being restored. Thus, if for example, a maxilary arch is missing teeth #1,3, 7-10 and 16, the RPD would be Kennedy Class III model 1. It would not be Class I, because missing third molars are generally not restored in an RPD (although if they were, the classification would indeed be Class I), and it would not be Class IV, because modification spaces are not allowed for Kennedy Class IV.

The Occlusal Splints (night-guard)

An occlusal splint or sometimes called night guard is mostly recommended to patients that are heavy grinders, or bruxes*.

Since most of the damage caused by teeth grinding is when we sleep, a splint ussually stops or prevent further damage.

The guard is custom made the upper or lower arch of the mouth. When the night guard is in place, the patient can not grind their teeth together and cause more damage.

The guard is worn during night maybe 4-5 nights a week and has been proved that they reduce the chance of fracture and tooth surface loss in the long run.


*Bruxism is the nocturnal unconscious grinding or gnashing of the teeth. It has been linked to stressful life events and occlusal or bite irregularities. Research shows that the maximun clench force capability during bruxism is up to 4 times the maximun conscious force in some subjects.

What is a dental attachment?

An attachment is a connector that is formed of 2 or more parts. One part is connected to a root, tooth, or implant and the other part to a prosthesis. There are certain exceptions as some attachments have only one manufactured part and the other part must be made by the dentist or the dental technician.

Attachments can be divided into two categories: Precision and Semi-Precision. We will examine both of them prior to attachment consideration.

Precision Attachments

Precision attachments are just that - "precision". Their components are machined in special metal alloys under precise tolerances. These tolerances are within 0.01 mm. Since the specific hardness of the alloys is controlled, precision attachments offer the advantage of less wear on the abutments, and standard parts which allows the components to be interchangeable, and usually easier to repair when necessary.
Semi-Precision Attachments

A semi-precision attachment is fabricated by the direct casting of plastic, wax, or refractory patterns. Most semi-precision attachment patterns are injection molded to reduce the overall cost. They are considered "semi-precision" since in their fabrication they are subject to inconsistent water/powder rations, burn out temperatures, and other variables. The resulting components therefore, vary to a small degree.

Their main advantages are: economy, easy fabrication and ability to be cast in a wide choice of alloys without the problem of co efficiency differences between the cast alloy and the machine alloy.


http://www.attachments.com/