Types of crown & bridges

Details about types of Fixed Prosthesis

1. Types of crown & bridge Dr Yumna Shaheen Ali

2. Crown

3. Definition of crown An artificial replacement that restores missing tooth structure by surrounding part or all of remaining tooth structure with a material such as metal, porcelain or combination of materials such as metal and porcelain.

4. Different types Of crowns

5. a) Anterior complete crowns for vital teeth Ceramic Crowns Metal Ceramic Crowns Other types of Crowns

6. i ) Ceramic Crowns Most esthetically pleasing No metal to block light transmission Can be virtually indistinguishable from unrestored teeth

7. advantages Highly aesthetic and high strength materials Resist plaque accumulation. Relative brittleness can be regarded as an advantage specially in class 2 div I patients where crown is most likely to fracture rather than root. DISADVANTAGES More tooth reduction Brittleness, in most cases is a disadvantage

8. Indications Where there are high aesthetic demands. (particularly in incisal area) CONTRAINDICATIONS Where more conservative restoration can be carried out .(same for all crowns) Providing a shoulder of 1 mm would compromise support. (it should be of 2mm)

9. ii) Metal Ceramic crowns Dental porcelain can be bonded to a variety of metal alloys such as Gold, Silver, nickel etc

10. adVantages High strength. Adequate tooth reduction can be done on palatal side in teeth which are severely worn by erosion. DISADVANTAGES As crown is stronger than natural dental tissues so an accidental blow can result in fracture of root. To achieve aesthetics margin is often placed subgingivally, causing periodontal problems

11. Indications Aesthetics Can serve as a retainer for fixed dental prosthesis due to its metal substructure. CONTRAINDICATIONS Active carious lesions & perio problems. Young patients with large pulp chambers.

12. iii) Other types of crowns Cast metal crowns with acrylic or composite facings. Fibre -reinforced composite crowns.

13. b) Anterior crowns for root filled teeth Composite core & crown Post and core & separate crown One-piece post crown Other types (composite or metal-ceramic crown retained by pins)

14. c) Posterior complete crowns Cast metal crowns Metal-ceramic crowns Ceramic crowns

15. i ) Cast metal crowns Traditionally a GOLD Alloy is used for posterior metal crowns but because of high cost many alternative alloys are introduced containing less gold and in some cases none.

16. advantages Greater retention and resistance Less tooth preparation required. DISADVANTAGES Poor esthetics

17. indications Tooth with extensive coronal destruction On short clinical crowns Where maximum retention and resistance is required CONTRAINDICATIONS High aesthetic need

18. ii) Metal ceramic crowns Advantages Principal advantage is their appearance. Porcelain can be used on buccal and occlusal surfaces of lower teeth and reverse is true for upper jaw . Disadvantages In short clinical crowns there comes a problem of retention. With an amalgam core greater reduction may expose the pins.

19. indications Aesthetics Retention and resistance required CONTRA INDICATIONS Active carious lesions & perio problems. Young patients with large pulp chambers.

20. Iii) Ceramic crowns ADVANTAGES Reasonable to use with a post and core Better appearance then a metal ceramic crown DISADVANTAGES More tooth preparation is required

21. indications Aesthetic CONTRAINDICATIONS Providing a shoulder of 1 mm would compromise support.

22. d) Posterior partial crowns Three-Quarter Crowns Seven-Eighths Crowns

23. i ) three-quarter crowns They cover four-fifth of the tooth’s surface, buccal surface remains intact. They are retained by grooves on mesial , distal and occlusal surfaces. They are always made of cast metal.

24. ii) Seven eighth crowns Covers all but mesial buccal cusp of an upper molar tooth. Retained by intracoronal features or adhesive techniques.

25. advantages More conservative Possible to test vitality of tooth via buccal surface. Periodontal problems are less. DISADVANTAGES Preparation is bit difficult Less retention

26. indications Teeth with sufficient bulk Can be used for retainers for fixed partial denture, bridge or spring cantilever design. CONTRAINDICATIONS Malpositioned teeth Short clinical crowns Teeth that are thin bucco-lingually

27. bridges

28. Definition of bridge Any dental prosthesis that is luted , screwed or mechanically attached to natural teeth, tooth roots and/or implant abutments that furnish primary support for dental prosthesis.

29. Materials for construction of bridge work Metal Metal-ceramic All-ceramic acrylic

30. Different Types of bridges

31. a) Fixed fixed bridge Has rigid connectors at both ends of pontics which forms a rigid prosthesis.

32. ADVANTAGES Provides cross arch splinting. Ease of handling DISADVANTAGES Possible bending of bridge Mobility of abutments may result in open margins All units have to be cemented simultaneously

33. b) Fixed movable bridge It has a rigid connector usually at the distal end of the pontic & a movable connector that allows some vertical movement of the mesial abutment tooth.

34. advantages Allows flexure of mandible Allow units to be cemented as individual sections. DISADVANTAGES More space required Metal may show occlusally Wear of joints

35. c) Cantilever bridge It’s a kind of minimal preparation bridge.It provides support for the pontic at one end only. The pontic may be attached to a single retainer or two or more retainers splinted together. e.g : maryland bridge, rochette bridge

36. advantages Preserve tooth structure Minimal pulp trauma Rebond possible DISADVANTAGES Length of span is limited to one pontic only. Occlusal forces on the pontic encourage tilting of abutment tooth. Not successful for posterior prosthesis.

37. d) Spring cantilever bridges They are restricted to the replacement of upper incisor teeth. Only one pontic could be supported by a spring cantilever bridge.

38. advantages Restoration of spaced dentition DISADVANTAGES Food impaction under metal connector Fracture of metal connector Dislodgment of retainer