CLASSIFICATION OF RPD - SEMINAR

              CLASSIFICATION OF RPD

CONTENTS

n Introduction.

nNeed for classification.

nRequirements of classification.

nDifferent systems of classification.

nConclusion.

nReferences.

INTRODUCTION

1.     The  primary purpose of creating  a classification system for partially edentulous arches is to enable the dentist to clearly communicate to a listener or reader ,  the  condition of oral cavity in which missing  teeth  are to be replaced  with  a prosthesis.

2.     It would be helpful to classify partial edentulous arches that share common attributes, characteristics, qualities and trials.

3.     It has been estimated that there are over 65,000 possible combination of teeth and edentulous spaces in opposing arches.

4.     Several classifications have been proposed and in use but a method which best classifies all possible configuration is still not achieved.

NEED FOR CLASSIFICATION:

1.     To formulate a good treatment plan.

2.     To anticipate the difficulties commonly to occur for particular design.

3.     To communicate with professionals.

4.     To design the denture according to occlusal load usually expected for a particular group.

REQUIREMENTS OF CLASSIFICATION:

Classification should satisfy these norms for acceptance: –

 1.  Allow visualization of the type of partially edentulous arch being considered.

 2. Permit differentiation between tooth supported and tooth tissue supported partial dentures.

 3. Serve as a guide to the type of design to be used.

 4.  Be universally accepted.

EVOLUTION OF DIFFERENT SYSTEMS OF CLASSIFICATION:

                                                                                                                   

CLASSIFICATIONS

n  A number of classifications have put forward some have been over simplified and others are immensely complex.

n  One simple system classifies the prosthesis according to the type of support they receive from dental arch.

           Soft tissue supported.

           Tooth supported.

           Tooth tissue supported.

                           

                                                                                                                                                                                       

                                          

n  Demerits –

n  There are many possible variations of tooth tissue supported partial denture that is simplified and this does not adequately describe the design that must be considered.

n  Therefore this system is not suited for general use in discussing, identifying or planning the prosthesis.

CUMMERS CLASSIFICATION SYSTEM 1920;

n  It is based on the relationship of the edentulous spaces to the abutment teeth.

n  This was the first recognized classification by the professional.

n  It is based on the number and position of the direct retainer.

n  Class 1- Diagonal:-Partially edentulous arch in which two    diagonally opposite teeth are chosen as abutment teeth for attachment of the direct retainers with an indirect retainer as an auxillary attachment.

                                     

Class 2- Diametric:-  Partially edentulous arch in which two diametric opposite teeth are chosen as abutment teeth for the attachment of the direct retainer.

                           

Class 3 – Unilateral; A partially edentulous arch in which one or more teeth on same side are chosen as abutment for the attachment of the direct retainer.  

                             

Class 4 – Multilateral; A partially edentulous arch in which two or more teeth are chosen as abutment for the attachment of the direct retainer.

                                 

KENNEDY CLASSIFICATION:

Class I -   Bilateral edentulous areas located posterior to the remaining natural teeth.

Class II - A unilateral edentulous area located posterior to the remaining natural teeth.

Class III – A unilateral edentulous area with natural teeth remaining both anterior and posterior to it.

Class IV – A single, but bilateral (crossing the midline), edentulous area located anterior to the remaining natural teeth.

         

          

Advantages:

1.     It Permits immediate visualization of the partially edentulous arch.

2.     It Permits a logical approach to the problems of design.

3.     It makes possible the application of sound principles of partial denture design.

Dr. O.C. Applegate –1960
attempted to expand the Kennedy classification by adding classes V and VI.

n  Kennedy referred to each additional edentulous area  and not each additional missing tooth as a modification area and included them in the classification  by number of such areas.

n  Class 1 arches being the most common and class 4 being the least common.

n  Class1 partial denture is designed  as tooth tissue supported prosthesis.

n  Class 3 as wholly tooth supported partial denture.

n  Class2 as combination of 1 and 3 partly tooth tissue supported and partly tooth supported.

APPLEGATE RULES:

n  Classified partially edentulous arches based on kennedys classification.

n  Any teeth require extraction it should be done prior to classification.

n  Applegate has given 8 rules as follows  -

n  Rule 1- Classification should follow rather than precede extractions that might alter the original classification.

n  Rule 2- If 3 molar is missing and not to be replaced, it is not considered in the classification.

n  Rule 3- If 3 molar is present and is to be used as abutment it is considered in the classification.

n  Rule 4- If 2 molar is missing and not to be replaced it is not considered in the classification

n  Rule 5-The most posterior edentulous area or areas determine the classification.

n  Rule 6 –Edentulous areas other than those determining the classification are referred to as modification spaces and are designated by there number.

n  Rule 7 – The extent of modification is not considered only the number of additional edentulous areas.

n  Rule 8- There can be no modification areas in class4 arches .Any edentulous area lying posterior to single bilateral area determine the classification

BAILYN CLASSIFICATION -1928

n  Bailyn system introduced a classification based on whether the prosthesis is tooth borne, tissue borne and combination of the two that is based on support.

n  Bailyn divided all removable partial dentures into anterior restoration and posterior restoration using the letters A and P.

n  A - Anterior restorations where there are saddle areas anterior to the first bicuspid (premolar).

n  P -Posterior restoration saddle area posterior to canine.

n  Further they are subdivided into –

n  Class 1- Bounded saddle (not more than three teeth missing).

n  Class 2-Free end saddle (there is no distal abutment).

n  Class 3 –Bounded saddle (more than 3 teeth missing).

n  If both anterior and posterior teeth are missing to be mentioned separately. Examples; A1P1, A2P1 etc.

n  Bailyns classification was the first to emphasize on the importance of support of partial dentures by remaining tissues

          

                

         

NEUROHR CLASSIFICATION -1939

n  This system was classified according to the type of support available, but the system was unnecessary complex and not commonly used.

n  Many of the denture designs did not match the principles of classification.

n  Class 1 –Tooth bearing.

n  Class 2 –Tooth and tissue bearing.

n  Class 3 –Tissue bearing complete denture.

n  Class 1 - Tooth bearing

n  Unilateral or bilateral case falls under the above classification when there are teeth posterior to all spans and when there are no more than four teeth missing in any space.

n  There are two possible variation.

Variation 1- Missing posteriors predominate.
         A) Posteriors missing anteriors in place.
         B) Posteriors missing some anteriors missing.

Variation 2 - Missing anteriors predominate.
A) anteriors missing posteriors present.
B) anteriors missing  some posteriors missing

              

              

Class 2- Tooth and tissue bearing:

n  Unilateral or bilateral case falls under the above classification when there are no teeth posterior to one or more spans or when there are more than 4 teeth in one or more spans (which includes canine).

n  Class 2 -subdivided into divisions with variations.

Division 1- When there are no teeth posterior to one or more spans.
Variation 1-Missing posteriors predominate.
                a)Posteriors missing anteriors in place.
                b)Posteriors missing and some anteriors missing.

           

Variation 2- Missing anteriors predominate.
 A) None.
 B) Anteriors missing some posteriors missing

                 

Division 2-When there are teeth posterior in all spans ,but when there are more than 4 teeth  including canine in any one or more  spans.

Division 2 has two possible variations-

Variation 1- Missing posteriors predominate.
 a)None .
 b) Posteriors missing some anteriors missing.

Variation 2- Missing anteriors predominate.
a) Anteriors missing posteriors in place bilaterally.
b) Anteriors missing some posteriors missing.

Class 3-Tissue bearing complete dentures.
The complexity of any neurohrs classification is obvious and seldom used.

Mauks Classification -1942

n  Mauk proposed a classification based on number ,length and position of  the edentulous spaces and the number and position of the remaining teeth.

n  According to the classification;

n  Class1 –Bilateral space with no teeth posterior to one space.

                  

Class2 – Bilateral space with teeth posterior to one space.
Class 3 – Bilateral space with teeth posterior to both space.

Class 4 – Unilateral space with no teeth posterior to it .The opposite arch is unbroken.

Class 5 – Anterior space with unbroken posterior arches on both sides.
Class 6 -   Irregular spaces around the arch, the remaining teeth may be single or in groups.

                                                                   

Wilds Classification – 1949

n  Wild proposed a simple but self explanatory classification little known in the English dental literature.

n  Class 1 –Interruption of dental arches (bounded)

           

Class 2 - Shortening of dental arches (free end).

Class 3 – Combination of 1 and 2.

            

Godfreys  Classification- 1949

n  Is based on location and size of the edentulous spaces. The specialty of this classification is that the main classes have no modifications.

n  Class A –Tooth borne denture base in the anterior part of the mouth. It may be unbroken five tooth space, broken five tooth space or unbroken four tooth space.

n   Class B – Mucosa borne denture base in the anterior region. It may be an unbroken six tooth space, an unbroken five tooth space or a broken five tooth space.
Class C -  Tooth borne denture base in the posterior part of the mouth .It may be an unbroken three tooth space , broken three tooth space , an unbroken two tooth space or broken two tooth space.                     

n  Class D – Mucosa borne denture base in the posterior region.It may be an unbroken four tooth, three tooth ,two tooth or a single tooth space.

                     

Friedman’s classification  -1953

n  He introduced ABC classification where ,

n  A – Anterior.

n  B - Bounded posterior.

n  C - Cantilever.

                  

Beckett and Wilson’s Classification-1957

n  Based on ideas of Bailyns classification the following must be considered while determining the proportionate amount of support provided by the teeth and tissue.

n  1. The quality of the abutment support.

n  2. The magnitude of occlusal support.

n  3. The harmony of occlusion.

n  4. The quality of mucosa and residual ridge.

n  They believed every effort should be made to avoid tissue support alone.

 

Class 1 - Bounded saddle – Abutment teeth qualified to support the denture. Mucosa is not used for support.

Class 2 –Free end.
              A) Tooth and tissue borne.
              B) Tissue borne.

Class3 –Bounded saddle –Abutment teeth not so qualified for support the denture as described in C lass1.

                  

n  Wilson in 1957 elaborated the classification as follows –

n  Mandibular Kennedy class3 should be treated as class 1.

n  Maxillary Kennedy class3 should be treated as class1or3.

Cradock’s Classification-1954

n  Classified partial dentures as ;

n  Class 1 –saddles supported on both sides by substantial abutment teeth.

Class 2 –Vertical biting forces applied to the denture resisted entirely by soft  tissue.

Class 3 –Tooth supported at only one end of the saddle.

                          

Swenson’s Classification 1955

n  Simple classification proposed by Swenson and Terkala.

n  It is not widely used .It is similar to Kennedy’s classification.The classes of Kennedy’s classification are dramatically changed.

n   

Class 1 – An arch with one free end denture base.
Class 2-An arch with two free end denture bases.

Class 3 – An arch with an edentulous space posterior on one or both sides of the mouth but with teeth present interiorly and posterior to each space.

Class 4 – An arch with an anterior edentulous space with five or more anterior teeth missing.

                   

Subdivision –The four major classes are subdivided without denoting which tooth is missing.
A - Anterior.
P - Posterior
AP – Anterior and posterior.
Ex – Class2 A denotes bilateral distal extension base with some anterior missing.

Austin and Lidge Classification-1957

n  Classification that described the position of teeth.

n  Class A –Missing anteriors.

n   A1: Missing anteriors on one side unilateral   construction.

n  A2 :Missing anteriors on both sides

n  AB1: Missing anteriors with bilateral construction.         

Class P – Missing posteriors.

P1 :Missing posteriors on one side unilateral construction.
P2 : Missing posteriors on both sides.
PB1: Posteriors missing on one side with bilateral construction.

Class AP – Missing anteriors and posteriors.
AP1: Missing anteriors and posteriors on one side (unilateral construction).

AP2: Missing anteriors and posteriors on both sides.
APB1: Missing anteriors and posteriors on one side with bilateral construction.
Any combination of the above may be possible.Ex A2P1 or A1P2.

Watt et al Classification 1958

n  It is based on type of support.

n  Entirely tooth borne-the entire denture rests on the abutment.

n  Entirely tissue borne-the entire rests on tissue.

n  Partially tooth borne and partially tissue borne- these dentures rests on both teeth and tissues.

n  Generally most RPD come under this category.

n  Skinners Classification 1959

n   His classification was influenced by Cummers classification. Similar to Cummers classification with five classes.

n  Class1 –Abutment teeth are present anterior and posterior to the edentulous space. It may be unilateral or bilateral.

n  Class2 – All the teeth are present posterior to the denture base which function as a partial denture unit. It may be unilateral or bilateral.

n  Class3 –All abutment teeth are anterior to the denture base which function as a partial denture unit. It may be unilateral or bilateral.

  Class 4- Denture bases are located anterior and posterior to the remaining teeth these may be unilateral or bilateral.

Class 5- Abutment teeth are unilateral in relation to denture base and these may be unilateral or bilateral.

.             

            

Avants Classification-1966

n  Similar to Kennedy’s classification without any improvements.

n  The classification was based on anterior and posterior segments of the arch.

Costas Classification-1974

n  It is based on anterior, lateral and terminal spaces.

Osborne and Lamies Classification -1974

n  Similar to Watt et als classification.

n  Class 1 – Mucosa borne.

n  Class2 –Tooth borne.

n  Class 3 - combination of tooth borne and tissue borne.

 

Conclusion :

n  Many classifications of partial dentures and design have been proposed by different clinicians.

n  A classification is either one that describes the various tooth and saddle position like those of Kennedy and others or one that looks more closely at the available support like those of Bailyn and others.

n  Kennedy classification describes basic outline of any particular case and form a common partial denture language among dentist but it does not take into account the available support upon which the success or failure of any partial denture or bridge ultimately depends.

n  For this reason support classification is preferable.

 References

n  Clinical removable partial prothodontics

          2nd edition Stewart, Rudd and kuebker.

n  Mc Crackens Removable partial prosthodontics.

8th edition, Mc Givney castle Berry.

n  System of classifying partial edentulous arches.

           J Prosthet Dent 1970 vol-24 no.1pg 24 –40.