Types of Fixed Partial Dentures for BDS.

for BDS students

1. Types of Fixed Partial Dentures Dr Anmol Asghar Ali BDS, PG Oral Implantol ADA Certified PG DIP:Orthodontics & Dentofacial Orthopadics USC Spain

2. Introduction . Since the classification is based on different factors ( design, material used, etc ), the denture designs described here are independent and may over lap in certain aspects

3. CONVENTIONAL FIXED PARTIAL DENTURES They are the most commonly used type of fixed partial dentures. The design involves fabrication of a fixed partial denture, which takes support from abutments on either side of the edentulous space.

4. CANTILEVER FIXED PARTIAL DENTURES A cantilever fixed partial denture is used when support can be obtained only from one side of the edentulous space

5. Advantages • Very conservative design especially when a single abutment is involved. • When secondary abutments are used, parallel preparation can be easily obtained because the abutments are adjacent to one another. • Easy to fabricate

6. Disadvantages • Produces torquing forces on the abutment • Cannot be used to restore long span edentulous spaces • Minor design errors can affect the abutments in a large scale

7. SPRING CANTILEVER FIXED PARTIAL DENTURES This is a special cantilever bridge exclusively designed for replacing maxillary incisors but these dentures can support only a single pontic. Support is obtained from posterior abutments (usually a single molar or a pair of splinted premolars ).

8. Advantages • Can be used for diastema cases. • Metal crown retainers that require minimal tooth preparation, can be used in posterior teeth to replace missing incisors

9. Disadvantages • The connector bar may interfere with speech and mastication • Deformation of the connector bar may produce coronal displacement of the pontic. • There may be food entrapment under the connector bar, which may lead to tissue hyperplasia.

10. FIXED FIXED PARTIAL DENTURES The term denotes fixed partial dentures with rigid connectors . The design of these dentures is more conventional Since the connectors are rigid , there can be no movement between the connected components. These are the most commonly used fixed partial denture designs

11. Advantages The major advantages of these partial dentures include: • Easy to fabricate • Economical design • Strong • Easy to maintain • Robust design provides maximum retention and strength • Helps to splint mobile abutments • Can be used for long bridges alongwith periodontally weak abutments.

12. Disadvantages • Since the connectors are rigid, unwanted stress and lever forces are directly transferred to the abutment producing considerable damage. • Requires excessive tooth preparation to achieve a single path of placement. • Difficult to cement on multiple abutments • Contraindicated for pier abutments

13. FIXED MOVABLE PARTIAL DENTURES It is defined as, “A fixed partial denture having one or more non-rigid connectors”

14. Advantages • They act like stress breakers while transmitting unwanted leverage forces. • The abutment is pressurized only during occlusal loading. • Improves the health of the abutment. • The tooth preparations need not be parallel to one another. Each abutment tooth can be prepared independently according to its requirements. • Allows minor movements between the components of the prosthesis. • Parts of the prosthesis can be cemented separately

15. Disadvantages • Complex design. • Prefabricated connector components are very expensive. • Difficult to maintain. • Movable parts tend to wear out under constant usage. • Cannot be used for long span bridges • Complicated laboratory procedures • Difficult temporisation

16. FIXED REMOVABLE PARTIAL DENTURES/ REMOVABLE BRIDGES One of the major disadvantages of long span fixed partial dentures is that if one abutment fails, the entire prosthesis has to be sacrificed. To overcome this disadvantage, fixed removable bridges were introduced. These dentures cannot be removed by the patient but can be easily removed by the dentist.

17. Design Individual cast gold copings are cemented over the abutments. Threaded sleeves are incorporated into the copings of few abutments. The bridge is retained over the copings by using weak cements and screws, which pass through a hole in the retainer into the threaded sleeves of the coping

18. M ODIFIED FIXED REMOVABLE PARTIAL DENTURES These dentures have an interesting design. They were developed by Andrew, hence they are also known as Andrew’s bridge systems These dentures are indicated for edentulous ridges with severe vertical deficit. The prosthesis consists of a fixed component and a removable component.

19. Biomechanics The bar is usually rectangular in cross section with the height more than the width The bar of an Andrew’s bridge should be taller and not broader to enhance rigidity. C—Compressive stress, T—Tensile stress

20. ALL METAL FIXED PARTIAL DENTURES These dentures are fabricated using only metal .

21. Characteristics • They are indicated for replacing maxillary and mandibular posterior teeth. • They are not aesthetic. • They have the maximum strength and durability

22. METAL-CERAMIC FIXED PARTIAL DENTURES Here, metal is used to fabricate the core of the prosthesis. The external surface is fabricated using ceramic. The metal is bonded to ceramic chemically, mechanically and ionically . Metal ceramic fixed partial dentures can be of two types. In the first type, the metal is surrounded by porcelain on all the surfaces In the second type the lingual and occlusal surface is formed by metal and the labial and gingival surface is alone formed by porcelain. These restorations are also termed as porcelain facings or porcelain veneers

23. PFM BRIDGE TYPE one

24. PFM BRIDGE TYPE 2

25. Advantages • Aesthetically pleasing • Stronger metal substructure • Characterization possible with use of internal and external stains

26. Disadvantages • Significant tooth preparation necessary; not conservative. • To achieve better aesthetics, the facial margin of an anterior restoration is often placed subgingivally , this increases the potential for gingival destruction. • Slightly inferior in aesthetics compared to all ceramic restorations. • Brittle fracture can occur due to failure at the metal ceramic junction. • Expensive

27. ALL CERAMIC FIXED PARTIAL DENTURES All ceramic partial dentures are fabricated using only ceramic. All ceramics are less fracture resistant, hence, they do not render as good retainers

28. Advantages • Superior aesthetics. • Excellent translucency. • Requires slightly more preparation of the facial surface . • The appearance can be influenced and modified by selecting different colors of luting agent

29. Disadvantages • Reduced strength due to lack of reinforcement with metal • It is very difficult to obtain a well-finished margin because the ceramic edges tend to chip easily . • These crowns cannot be used on extensively damaged teeth because they cannot support these restorations. • Due to porcelain’s brittle nature, large connectors have to be used, which usually leads to impingement of the inter-dental papilla. This increases the potential for periodontal disease. • Wear of opposing natural teeth

30. ALL ACRYLIC FIXED PARTIAL DENTURES Only indicated for long-term temporary or interim prostheses. Can be used for making fixed periodontal splints . Poor wear resistance. Easy to fabricate and adjust Aesthetically Okay.

31. VENEERS Veneer is a layer of restoration placed over the labial surface of a tooth. They are primarily used as aesthetic adjuncts to discolored or fractured teeth .

32. Type of Veneers Ceramic It is the most ideal veneering material when used with metal substructure or in all ceramic restorations. Acrylic Tooth colored acrylic can be used with metallic restorations as a veneer. They are not considered as a permanent material due to poor wear resistance. Recent advances include use of indirect composite resins as veneer materials.

33. SHORT SPAN BRIDGES These are simple fixed partial dentures, which replace one or two teeth, and the teeth on either side are ideal abutments

34. LONG SPAN BRIDGES Long span bridge denotes a condition where two or more teeth have to be replaced and more than one abutment has to be taken for support on either side

35. FIXED PARTIAL DENTURE SPLINTS Splinting either on the same side or on both sides is a necessary adjunct to the treatment of periodontally involved teeth. Splinting several single rooted teeth transforms them into a single multi rooted unit.

36. Purpose of Splinting The purpose of the splint should be to distribute and direct the functional forces, to bring them within the tolerance of the remaining supporting tissues and to eliminate any mobility that may be present.

37. Classification of Splints Based on the extent of the prosthesis across the midline , fixed partial denture splints can be classified as : • Unilateral splints • Bilateral or cross-arch splints Based on the duration of use, fixed partial denture splints can be classified into: • Temporary or provisional splints • Permanent splints

38. Unilateral Splints Unilateral splinting denotes the joining of two or more teeth in one plane of an arch segment. These splints are more resistant to mesio -distal forces. They show poor resistance to bucco -lingual forces

39. Bilateral Splints A bilateral or cross-arch splint is a splint, which crosses the midline. It may involve two or more segments of an arch or involve the entire arch. Here the splinting action is resistive to forces in all directions

40. Temporary Splints Temporary or provisional or healing splints are employed for a limited period of time. They are indicated for the following conditions: • To aid in healing by limiting the mobility of healing tissues. • To immobilize and relieve the periodontium prior to periodontal surgery. • To assist in determining the prognosis of periodontally weak teeth.

41. Permanent Splints Permanent splints serve as constant adjuncts to the maintenance of periodontal health. They help to prevent further progression of periodontal disease . (Note: Splints can never improve the periodontal status. They can only prevent or slacken the progression of the disease).

42. FIBRE REINFORCED COMPOSITE RESIN BRIDGES These, basically, are bridges, which are reinforced by a bar of glass fibres over which indirect posterior composites are built

43. Contraindications • It cannot be used when fluid control is not possible • Cannot be used for long span bridges • It should be avoided in patients with para functional habits • It should not be used opposing unglazed porcelain teeth.

44. Advantages • Optimal aesthetics • Metal free • Decreased wear of opposing teeth

45. Tooth Preparation • Tooth preparation is done on the lingual or palatal surface with a flat end-tapering diamond as done for a Resin bonded FPD. • Additionally a thin box or a groove like preparation is done on the palatal surface near the edentulous side on the coronal half of enamel

46. Rochette Bridge Rochette was the first to design a resin-bonded prosthesis (1973). He used wing like retainers with funnel shaped perforations with the base towards the tooth surface

47. MARYLAND BRIDGE