Introduction & classification of removable partial denture

Removable Partial Denture

1. INTRODUCTION & CLASSIFICATION OF REMOVABLE PARTIAL DENTURE MADE BY: Abhinav Mudaliar (2010-2011)

2. DEFINITION- PROSTHODONTICS Defined as the “branch of dentistry pertaining to the restoration and maintainence of oral function,comfort,appearance and health of the patient by restoration of natural teeth or the replacement of missing teeth and contiguous oral and maxillofacial tissues with the artificial substitution.

3. BRANCHES 3 major divisions: -fixed prosthodontics -maxillofacial prosthetics -removable prosthodontics complete partial extracoronal intracoronal

4. REMOVABLE PROSTHODONTICS It is devoted to replacement of missing teeth & contigous tissues with prosthesis designed to be removed by the wearer.It includes two disciplines: removable complete denture prosthodontics and removable partial denture prosthodontics. A RPD may be extracoronal or intracoronal depending on what type of retention is used to keep it in the mouth.

5. COMMON TERMINOLOGIES USED IN RPD Appliance It is a device worn by a patient in the course of treatment. e.g. orthodontic appliance, surgical ,space maintainer. Abutment “A tooth,a portion of a tooth ,or that portion of a dental implant that serves to support & or retain a prosthesis.” Retainer The fixation device ,or any form of attachment applied directly to an abutment tooth & used for the fixation of a prosthesis, is called retainer.

6. Extracoronal partial denture T he retention of this prosthesis depends on the exact parallelism of the two retentive units. Tooth supported RPD A partial denture that receives support from the natural teeth at each end of the edentulous space or spaces. Tooth tissue supported RPD The denture base that extends anteriorly / posteriorly and is supported by teeth at one end and tissue on the other end – distal extension partial dentures.

7. Temporary removable partial denture T hey are used in patient where tissue changes are expected, where a permanent prosthesis cannot be fabricated till the tissues stabilize. Interim denture It is a temporary partial denture used for a short period to fulfill aesthetics, mastication or convenience until a more definite form of treatment can be rendered.

8. Transitional denture May be used when loss of additional teeth is inevitable but immediate extraction is not advisable or desirable. Artificial teeth may be added to the transitional denture as and when the natural teeth are extracted. Treatment denture It is used as a career for treatment material. It is used when the soft tissues have been abused by illfitting prosthetic devices.

9. Centric relation I t is the most posterior relation of mandible to the maxilla at the established vertical dimension from which lateral movements could be made. Eccentric Relation Relationships of the mandible to maxilla other than centric relation that occur in horizontal plane. Centric Occlusion It is the maximum intercuspation between the upper and lower teeth.

10. Indications for RPD Length of edentulous : RPD preferred for longer edentulous arches. Abutment tooth: When there is no tooth posterior to the edentulous space to act as an abutment, a RPD is preferred. Periodontal support of remaining teeth: When it is poor RPD is preferred because it requires less support from the abutment teeth. Cross arch stabilization: When a remaining teeth have to be stabilized against lateral and anterior-posterior forces, a RPD is indicated.

11. Excessive bone loss: In RPD, the artificial tooth can be positioned as per the operators preferences and the denture base can be fabricated to provide required support and aesthetics. Aesthetics: RPD provide better aesthetics because the denture base gives the appearance of a natural tooth arising from the gingiva . Immediate tooth replacement after extraction Emotional problems: The appointment for removable partial denture is shorter and less demanding to patient. Patient desires: Patient insist on RPD over FPD for the following reasons: To avoid operative procedures on normal tooth. For economic reasons.

12. RPD is generally preferred in the following conditions: When more than 2 posterior teeth or 4 anterior teeth are missing. If the canine & two of its adjacent teeth are missing. When there is no distal abutment tooth. Presence of multiple edentulous spaces. If the teeth adjacent to edentulous spaces are tipped ,they cannot be used as an abutment for a fixed prosthesis. If periodontally weakened teeth are present near the edentulous spaces.

13. Teeth with short clinical crowns. Insufficient number of abutments Severe loss of tissue on the edentulous space. Old patients

14. Requirements of an acceptable method of classification . It should permit immediate visualization of the type of partially edentulous arch that is being considered. It should permit immediate differentiation b/w the tooth supported & the tooth and tissue supported RPD. It should be universally acceptable.

15. Classification of removable partial denture: Requirements of classification: Allow visualization of the type of partially edentulous arch that is being considered. Allow differentiation between tooth supported and tooth-tissue supported partial dentures. Serve as a guide to the type of design to be used. Be universally accepted. There are many classification available for classifying edentulous arches. The most common ones are:

16. CUMMER’S CLASSIFICATION: This is the first professionally recognized classification. It was introduced by Cummer in 1920. According to him partial dentures can be classified into four types based on the position of direct retainers: Diagonal: Two direct retainers are diagonally opposite to one another. Diametric: Two direct retainers are diametrically opposite to one another. Unilateral: Two or more direct retainers present on the same side. Multilateral: Three(rarely four) direct retainers in a triangular(rarely quadrangular) relationship.

17. Kennedy’s classification Class I: bilateral edentulous areas located posterior to the remaining natural teeth. Class II: unilateral edentulous areas located posterior to the remaining natural teeth.

18. Class III: unilateral edentulous area with natural teeth anterior and posterior to it, i.e. this indicates a single edentulous area which doesn’t cross the midline of the arch, with teeth present on both sides of it.

19. Class IV: single, bilateral edentulous area located anterior to the remaining natural teeth. This is a single edent. area, which crosses the midline of the arch, with remaining teeth present only posterior to it.

20. Applegate's modification (1960) Applegate modified the above classification based on the condition of the abutment to include 2 or more additional groups:

21. Class V: edent. area bounded anteriorly and posteriorly by natural teeth but in which the anterior abutment (e.g. LI) is not suitable for support. It is basically a class III situation for the anterior abutment cannot be used for any support.

22. Class VI: edent. area in which the teeth adj.to the space are capable of total support of the required prosthesis. This denture hardly requires any tissue support. Most of the RPDs are tooth tissue supported. Hence this condition is classified as a separate group.

23. Applegate’s rules Rule 1: classification should follow rather than precede extractions that might alter the original classification. Rule 2: if the third molar is missing and not to be replaced, it is not considered in the classification. Rule 3: if the third molar is present and is to be used as an abutment, it is considered in the classification. Rule 4: if the second molar is missing and is not to be replaced, it is not considered in the classification.

24. Rule 5: the most posterior edentulous area or areas always determine the classification. Rule 6: edentulous areas other than those, which determine the classification, are referred to as modification spaces and are designated by their no: Rule 7: the extend of the modification is not considered, only the no: of edentulous areas, i.e. the no: of teeth missing in the modification spaces is not considered only the no: of additional edentulous spaces are considered.

25. Rule 8: there can be no modification areas in class IV. Because any additional edentulous space will definitely be posterior to it and will determine the classification.

26. Beckett & Wilson’s classification They decided that the following must be considered while determining the prpportionate amount of support provided by the teeth & tissue. a)the quality of abutment support. b)the magnitude of occlusal support. c)the harmony of the occlusion. d)the quality of the mucosa &residual ridge.

27. class I:bounded saddle.abutment teeth qualified to support the denture.mucosa is not used for support. Class II:free-end a)tooth-&- tissue- borne b)tissue-borne.

28. Class III:bounded saddle.abutment teeth not so qualified to support the denture as described in classI.

29. Bailyn’s classification Proposed by Bailyn,it was the first classification to give importance to support of partial dentures by remaining tissues.he used descriptive letters like A& P . A - anterior restorations,where there are saddle areas antr to the 1 st bicuspid P -posterior restoration, where there are saddle areas posterior to the canine.

30. Further they are subclassified as follows: classI: bounded saddle(not more than 3 teeth missing) Class 2:free end saddle(there is no distal abutment tooth)

31. Class 3:bounded saddle(more than 3 teeth missing) Class1 is tooth supported,class2&3 are tooth-tissue supported.In cases where anterior & posterior teeth are missing ,the class of anterior &posterior teeth are mentioned seperately,eg:A1P1,A2P1,A1P3.

32. NEUROHR’S CLASSIFICATION: Proposed in 1939, it is also based on support derived.It is not commonly used due to its unnecessary complexity. Class I:Tooth-bearing A unilateral or bilateral case falls into the above classification when there are teeth posterior to all spans and when there are no more than four teeth missing in any space. There are two possible variation in this class. Variation 1:Missing posteriors predominate. --- Posteriors missing, anteriors in place. --- Posteriors missing, some anteriors missing. Variation 2:Missing anteriors predominate. --- Anteriors missing, posteriors present. --- Anteriors missing, some posteriors missing.

33. Class II: Tooth and tissue-bearing A unilateral or bilateral case falls into the above classification when there are no teeth posterior to one or more spans or when there are more than four teeth(which include a canine) in one or more spans. Class II is further sub-divided into divisions with variations under each: Division 1:When there are no teeth posterior to one or more spans: Variation 1:Missing posteriors predominate. ---Posteriors missing, anteriors in place ---Posteriors missing, some anteriors missing Variation 2:Missing anteriors predominate. ---None --- Anteriors missing , some posteriors missing

34. Division 2: When there are teeth posterior in all spans, but when there are more than four teeth(including a canine) in any one or more spans. Variation 1:Missing posteriors predominate. --- None --- Posteriors missing, some anteriors missing Variation 2:Missing anteriors predominate. --- Anteriors missing, posteriors in place --- Anteriors missing, posteriors missing Class III: Tissue bearing complete dentures

35. MAUK’S CLASSIFICATION: Proposed by Mauk in 1942, it is based on number, length and position of the remaining teeth. Class I: Bilateral space with no teeth posterior to it. Class II: Bilateral space with teeth present posterior to one space. Class III: Bilateral space with teeth present posterior to both spaces. Class IV: Unilateral space with no teeth posterior to it. Class V: Anterior space with unbroken posterior arches on both sides. Class VI: Irregular spaces around the arch. The remaining teeth are single or in small groups.

36. GODFREY’S CLASSIFICATION: Proposed in 1951, it is based on the location and size of edentulous spaces. Class A: Tooth-borne denture base in the anterior part of the mouth. It may be an unbroken five- tooth space, broken five-tooth space or an unbroken four-tooth space. 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, a broken three-tooth space, an unbroken two-tooth space, or a broken two-tooth space.

37. Class D: Mucosaborne denture base in the posterior region. It may be an unbroken four-tooth, three-tooth, two-tooth, or a single-tooth space.

38. THANKYOU……