Classification of Partially Edentulous Arches PDF

CLASSIFICATION OF PARTIALLY EDENTULOUS ARCHES Prof. Dr. Dilek Pınar Şenyılmaz D.D.S., PH.D., M.SC., D.I.C.O.I. Partially Edentulous Patient An individual who has lost some of his/ her natural teeth. Partial Denture: A prosthesis that replaces one or more, but not all of the natural teeth and support...

CLASSIFICATION OF PARTIALLY EDENTULOUS ARCHES Prof. Dr. Dilek Pınar Şenyılmaz D.D.S., PH.D., M.SC., D.I.C.O.I. Partially Edentulous Patient An individual who has lost some of his/ her natural teeth. Partial Denture: A prosthesis that replaces one or more, but not all of the natural teeth and supporting structures. PARTIAL DENTURE(S): A dental prosthesis that restores one or more but not all of the natural teeth and/or associated parts and that is supported in part by natural teeth, dental implant supported crowns, abutments, or other fixed partial dentures and/ or the mucosa; A partial denture should be described as a fixed partial denture or removable partial denture based on patient’ s capability to remove or not remove the prosthesis respectively. (GPT) Classification of Partial Dentures: I. Removable Partial Denture (RPD) II. Fixed Partial Denture (FPD) III. Dental Implant Therapy I. Removable Partial Dentures I.RPD also known as removable partial denture is where any prosthesis that replaces some teeth in a partially dentate arch. It can be removed from the mouth and replaced as well. Partial denture construction: The science and techniques of designing and constructing partial dentures. Removable prosthodontics: The branch of prosthodontics concerned with the replacement of teeth and contiguous structures for edentulous or partially edentulous patients by artificial substitutes that are readily removable from the mouth by the patient. There are 3 types of removable partial dentures (RPD): A- Acrylic partial dentures (Flipper) B- Cast partial dentures (Cr-Co) C- Flexible partial dentures (Valplast) Objectives for RPD Construction: 1. Restore esthetic (especially for anterior teeth). 2. Restore function (phonetic and mastication) for proper speech, proper occlusion and proper food mastication. 3. To prevent apposing teeth extrusion or migration and tilting of adjacent teeth. 4. To fill empty space or spaces. 5. To prevent disease atrophy by a form of stimulation to the underlying tissue and ridge. 6. For proper muscular balance. 7. To restore the psychological status of the patient. Main Causes of teeth loss: 1. Caries (main cause in young people below 35 years). 2. Periodontal diseases (main cause in old people above 35 years). 3. Trauma or accident (such as receiving a blow or falling down on them). 4. Congenital missing teeth. Indications* of Removable Partial Dentures (RPD) 1. Distal extension situations (free end situation). 2. Long span tooth-bounded edentulous area. 3. Need for cross-arch (bilateral) stabilization. 4. Excessive loss of the residual ridge. 5. Unusually sound abutment teeth. *Indication: A sign, symptom or medical condition that leads to the recommendation of a treatment, test, or procedure/ A condition which makes a particular treatment or procedure advisable. Indications of Removable Partial Dentures (RPD) 6. If the prognosis of remaining teeth is questionable or reduced periodontal support of remaining teeth (these teeth cannot support fixed prostheses). 7. After recent extraction (need immediate replacement of extracted teeth). 8. Patients younger than 18 years old. 9. Economic consideration. WHEN IS IT NOT SUITABLE TO HAVE RPD ??? Contraindications for a Removable Partial Denture: 1- A lack of suitable teeth in the arch to support, stabilize, and retain the removable prosthesis. 2- Rampant caries or severe periodontal conditions that threaten the remaining teeth in the arch. 3- A lack of patient acceptance for esthetic reasons. 4- Chronic poor oral hygiene. II. Fixed Partial Dentures (FPD) Any dental prosthesis that is luted, screwed, or mechanically attached or otherwise securely retained to natural teeth, tooth roots, and/or dental implants/abutments that furnish the primary support for the dental prosthesis and restoring teeth in a partially edentulous arch; it cannot be removed by the patient. Indications for Fixed Partial Denture: 1. Unilateral bounded edentulous short span. 2. Class IV Kennedy classification with normal loss of bone. 3. Modification area located anteriorly with Class I or with Class II Kennedy classification that simplifies the design of a removable partial denture. III. Dental implant therapy: Dental Implant: A prosthetic device made of alloplastic material(s) implanted into the oral tissues beneath the mucosal and/or periosteal layer and on or within the bone to provide retention and support for a fixed or removable dental prosthesis. Ø The dental implants are considered adjuncts in fixed and removable therapy. Ø However, not all patients are candidates for dental implant therapy. Contraindications for dental implant therapy: 1. Unfavorable regional anatomy. 2. Uncontrolled systemic disease. 3. Extreme surgical risk. 4. High-dose head and neck radiation. CLASSIFICATION OF PARTIALLY EDENTULOUS ARCHES CLASSIFICATION OF PARTIALLY EDENTULOUS ARCHES Need for a classification?? REQUIREMENTS OF ACCEPTABLE METHOD OF CLASSIFICATION: The classification of a partially edentulous arch should satisfy the following criteria… 1- It should permit immediate visualization of the type of partially edentulous arch that is being considered. 2. It should permit immediate differentiation between the tooth-supported and the tooth- and tissue-supported removable partial denture. 3. It should be universally acceptable. UNIVERSAL CLASSIFICATION It is evident that an attempt should be made to combine the best features of all classifications so that a universal classification can be adopted. The most familiar classifications are those originally proposed by: 1- Kennedy* 2- Cummer 3- Bailyn 4- Beckett 5- Godfrey 6- Swenson 7- Friedman 8- Wilson 9- Skinner 10- Applegate 11- Avant 12- Miller KENNEDY CLASSIFICATION KENNEDY CLASSIFICATION Ø The Kennedy method of classification was originally proposed by Dr. Edward Kennedy in 1925. Ø It attempts to classify the partially edentulous arch in a manner that suggests certain principles of design for a given situation. Ø Kennedy divided all partially edentulous arches into four basic classes. Edentulous areas other than those that determine the basic classes were designated as modification spaces. Classification of Partially Edentulous Arches The following is the Kennedy Classification: Class I - Bilateral edentulous areas located posterior to the 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 KENNEDY CLASS I AND CLASS II MANDIBLE MAXILLA KENNEDY CLASS I MAXILLA MANDIBLE KENNEDY CLASS II KENNEDY CLASS III AND CLASS IV MAXILLA MANDIBLE KENNEDY CLASS III MAXILLA MANDIBLE KENNEDY CLASS IV ü One of the principal advantages of the Kennedy method is that it permits immediate visualization of the partially edentulous arch and allows easy distinction between tooth-supported versus tooth- and tissue-supported prostheses. ü Those schooled in its use and in the principles of partial denture design can readily relate the arch configuration design to be used in the basic partial denture. ü This method permits a logical approach to the problems of design. It makes possible the application of sound principles of partial denture design and is therefore a logical method of classification. However, a classification system should not be used to stereotype or limit the concepts of design. APPLEGATE’S RULES FOR APPLYING THE KENNEDY CLASSIFICATION ü The Kennedy classification would be difficult to apply in every situation without certain rules for application. ü Applegate provide eight rules that govern application of the Kennedy method. APPLEGATE’S RULES ü RULE 1: Classification should follow rather than precede any extractions of teeth that might alter the original classification. ü RULE 2: If a third molar is missing and not to be replaced, it is not considered in the classification. ü RULE 3: If a third molar is present and is to be used as an abutment, it is considered in the classification. ü RULE 4: If a second molar is missing and is not to be replaced, it is not considered in the classification (for example, if the opposing second molar is likewise missing and is not to be replaced). ü RULE 5: The most posterior edentulous area (or areas) always determines the classification. ü RULE 6: Edentulous areas other than those determining the classification are referred to as modifications and are designated by their number. ü RULE 7: The extent of the modification is not considered, only the number of additional edentulous areas. ü RULE 8: There can be no modification areas in Class IV arches. (Another edentulous area lying posterior to the “single bilateral area crossing the midline” would instead determine the classification). Applegate Rule 1 Classification should follow rather than precede any extractions of teeth that might alter the classification. All extractions should be completed prior to determining the classification. This is important because the extractions may change the Kennedy Classification. For example, a patient may have a unilateral free-end saddle (Class II). If this patient then has posterior extractions on the opposite side of the same arch, then they may end up with bilateral free-end saddles and would be a Class I. Applegate Rule 2 If a third molar is missing and is not to be replaced, it is not considered in the classification. We very rarely would replace third molars and if patients do not have them, then we wouldn’t include these in the classification i.e. they don’t suddenly have free-end saddles. Applegate Rule 3 If a third molar is present and is to be used as an abutment, it is considered in the classification. This may be in a scenario where a patient is having their first and second molars replaced and so the denture utilizes the third molar as an abutment. As a result, the saddle is a bounded saddle and not a free-end saddle. Applegate Rule 4 If a second molar is missing and is not to be replaced, it is not considered in the classification. This would be the usual cases if the opposing second molar is missing, then we wouldn’t classically and replace the second molar as there would be nothing to occlude on. Applegate Rule 5 The most posterior edentulous area (or areas) always determines the classification. Ultimately, teeth missing in the most posterior areas will determine the classification. Edentulous spaces should first be assessed to see if they fall in to Kennedy Class I. Then Class II, followed by Class III and finally Class IV. This also links to Applegate’s Rule 1 where the class should be decided following extractions, as the extractions may be in the posterior regions. Applegate Rule 6 Edentulous areas other than those that determine the classification are referred to as MODIFICATION (S) and are designated by their number. Patients will often have multiple edentulous areas, for example several ‘bounded saddles’. Under the classification system, Class III describes a single bounded saddle and therefore, we need space for modifications. This is demonstrated below where we have a unilateral bounded saddle and an anterior bounded saddle – this is the modification. So the dentition below would be a Kennedy Class III Modification 1. Applegate Rule 7 The extent of the modification is not considered, only the number of additional edentulous areas are considered. It does not matter if there is one or several teeth in an edentulous space with regards to the modification – it is simply the number of spaces. Applegate Rule 8 No modification areas can be included in Class IV arches. If there are any other edentulous spaces, as the above rules dictate, the denture would fall into one of the other classes. Although some confusion may occur initially as to why Class I should refer to two edentulous areas and Class II should refer to one, the principles of design make this distinction logical. Kennedy placed the Class II unilateral distal extension type between the Class I bilateral distal extension type and the Class III tooth-supported classification because the Class II partial denture must embody features of both, especially when tooth-supported modifications are present. Because it has a tissue-supported extension base, the denture must be designed similarly to a Class I partial denture. Often, however, a tooth-supported, or Class III, component is present elsewhere in the arch. Thus, the Class II partial denture rightly falls between the Class I and the Class III, because it embodies design features common to both. In keeping with the principle that design is based on classification, the application of such principles of design is simplified by retaining the original classification of Kennedy. CLASS IV CLIASS II Modification 2 CLASS I Modification 1 CL III Mod 3 CL III Mod 1 CL III Mod 1 CL IV CL II CL III Mod 5 When we were DENTAL STUDENTS... THANK YOU VERY MUCH!!!.. REF. 1- McCracken's Removable Partial Prosthodontics 13th Edition. 2- Jeff Shotwell, Uni. Michigan Prof. Dr. Dilek Pınar Şenyılmaz D.D.S., PH.D., M.SC., D.I.C.O.I.