The partial veneer crown , inlay and onlay.pptx

Partial veneer crown

1. The partial veneer crown , inlay and onlay

2. Introduction . Partial veneer crowns generally include all tooth surfaces except the buccal or labial wall in the preparation. Therefore, it is more conservative than a complete crown , In addtion Gingival health near a partial coverage crown is protected by the supragingival margin ( Kahn AE. J Prosthet Dent 1960 )( Silness J. 1970) a tooth with a full coverage crown is about 2.5 times as likely to have a pulpal problem as one with a partial coverage crown . (Felton D. 1989) Ref. shilingburg fourth edition pg 388

3. Definitions : partial-coverage crown : an artificial replacement that restores missing tooth structure by surrounding part of the remaining structure with a material such as cast metal alloy, ceramics, or resin; it is retained by mechanical or adhesive means Ref ( The glossary of prosthodontics , ninth adition ) pg 66,

4. Inlay : a fixed intracoronal restoration; a dental restoration made outside of a tooth to correspond to the form of the prepared cavity, which is then luted into the tooth   Onlay : a partial-coverage restoration that restores one or more cusps and adjoining occlusal surfaces or the entire occlusal surface and is retained by mechanical or adhesive means Ref ( The glossary of prosthodontics , ninth adition ) pg 49,63

5. Partial veneer crown - (2) anterior: - (1) posterior: - pinledge preparation -maxillary canin 3\4 crown -maxillary central incisor pinledge - maxillary premolar and molar 3\4 crown mandibular premolar modified 3\4 crown - reverse 3/4 crown - 7\8 crown -proximal half crown

6. . Indications - posterior : -1. Tooth have lost moderate amounts of tooth structure if buccal wall is intact 2. retainer for an FDP 3. if alteration of the occlusal surface is needed Anterior : 1.retaining damaged teeth 2. . retainer for an FDP 3. splint teeth

7. . contraindications: Posterior : 1. short crown 2.extensive caries and periodontal diseases 3.extensive destructions 4. poor alingnment ( partial veneer crowns prepared at parallel axial walls ) 5. proximally bulbous teeth 6. thin teeth (tooth have a thin bacculingual diamention ) Need making proximal grooves  on these teeth will leave unsupported enamel Anterior: 1. short crown 2.extensive caries and periodontal diseases 3.extensive destructions 4. cervical caries 5. thin teeth

8. . advantages: 1 . conservation of tooth structure 2. easy access to margins ( supraGingival ) 3. less gingival involvement the with complete cast crown 4. easy verification of seating ( direct visibility ) 5. easy escape of cement and good seating 6. If an electric pulp test ever needs to be conducted on the tooth, a portion of enamel is unveneered and accessible ( Ho G. Lecture notes. Los Angeles: University of Southern California School of Dentistry, 1959)

9. Disadvantages : 1- less retentive than complete cast crown Lorey RE, Myers GE. The retentive qualities of bridge retainers . J Am Dent Assoc 1968 2. limited adjustment of path of withdrawal 3. some display of metal

10. . preparation : - (1) posterior: (1-1 )- maxillary premolar and molar 3\4 crown (1-2)- mandibular premolar modified 3\4 crown (1-3) – reverse 3/4 crown (1-4)- 7\8 crown (1-5 ) -proximal half crown - (2) anterior: (2-1)- maxillary canin 3\4 crown (2-2)- maxillary central incisor pinledge

11. (1-1) maxillary premolar 3\4 crown Ref .(contemporary pg244) 1 - occlusal surface preparation : A- Depth grooves : - pinholes in central groove ( misial , distal pits ) Depth of : 0.8 mm on nonfunctional cusps, 1.3 mm on functional cusp Use : fissure carbide or diamond parallel

12. - please grooves on ( misial , distal marginal ridge ) - grooves on ( the lingual incline of the buccal cusp, buccal incline of lingual cusp) Use : tapered, round-ended Diamond

13. B . occlusal reduction :   connecting between grooves  wide bevel at tip of the cusp Depth :  of 1mm ( on nonfunctional cusp ) 1.5mm (functional cusp ) - Assess the amount of occlusal clearance in maximum intercuspation

14. : 2 .axial preparation - Depth grooves for axial Reduction - Axial reduction : are prepared in the center of the lingual surface and in the Mesiolingual and distolingual transitional line angles ,  parallel the long axis of the tooth Depth of : 0.5 mm Use : tapered, round-ended - Diamond Axial reduction:  Chamfer margin finishing (0.5 mm supraginival )

15. 3- Proximal preparation . break proximal occlusal contact Use : needlepoint diamond . prepare proximal axial walls Use : tapered, round-ended Diamond (Chamfer margin finishing)

16. -. proximal grooves : The groove need not be deeper than 1 mm at its cervical end - placed as far as facially as possible ( buccal half of proximal surface)  Use : carbide bur no. 171 (0.5mm) Depth : 1mm -parallel to path of placement of restoration - stop short of margin 

17. -. Con.. proximal grooves : - it can be U shape ( most used ) V shape ( lest retentive and more conservative ) box shape (more retentive and lest conservative ) - Proximal flare 

18. Advantages of proximal grooves : - 1 . to improve retention 2.distinct resistance to lingual displacement 3. reinforce the margin of restoration at this area 4. act as guide during placement

19. 4- occlusal offset : 1mm .wide groove made on the lingual incline of the buccal cusp . inverted V shape lie at uniform distance from occlusal finish line - improve the strength of the casting - reinforce the margin of restoration at this area ( Ingraham R University of Southern California School of Dentistry, ( 1969

20. 5- Buccal and occlusal bevel Margins : - 45 degree bevel ( for structural durability )

21. - Keep metal display to minimum

22. (1-2)- mandibular molar 3\4 crown The principles used in a premolar preparation also apply for a maxillary molar except: 1- no occlusal offse t 2 - shoulder on buccal why ?? - Additional retention is required because of the shorter crown length of mandibular teeth - the buccal aspect of the madibular teeth includes the functional cusp

23. ( functional cusp ) Max . post  Position of the finising line on facial surface ( terminat near the bucco-occlusal line angle ) Mand.post  Position of the finising line 1mm gingival to the lower occlusal contact with upper teeth ( because the buccal cusps in lower are the functional cusps )

24. 3- proximal grooves extended more buccaly (because no need for esthetic ) 4 - beveled from mesial to distal

25. (1-3) – reverse 3/4 crown Buccal surface is included in the preparation instead of the lingual surface. Indications : 1- Mandibular molars with damaged buccal surface and intact lingual surface 2-Mandibular molars with sever lingual inclinations to be used as bridge retainers

26. (1-4)- 7\8 crown Three quarter crown with extension on buccal surface from distal side ( mesiobuccal cusp is not veneerd ) - Have better retention and resistance than three quarter crown Shillingburg 3ed pg 160   Indications : (generally used in maxillary 1 st molars with : - Intact mesiobuccal cusp - When there is extensive distal caries or previous restoration

27. (1-5 ) -proximal half crown A three quarter crown with the distal surface rather than the buccal has been left intact   Contraindications: - Caries on the distal surface - Patient with bad oral hygiene

28. Indications : ( single restoration or as retainer on) - Upper molars where it is difficulte to gait access to the distal surfaces - Lower mesially tilted molars - ( Shillingburg HT Jr. Bridge retainers for tilted abutments. N M Dent J 1972)

29. - (2) anterior partial veneer crown : - pinledge preparation (2-1)- maxillary canine 3\4 crown (2-2)- maxillary central incisor pinledge

30. pinledge preparation Pinledge retainer(2): pinledge (1998): a partial-coverage crown or retainer that incorporates pins that insert into corresponding pinholes prepared in the tooth Ref .( The glossary of prosthodontics , ninth adition ) pg 69

31. Indications 1-undamaged anterior teeth in dentitions with little or no caries. 2-if esthetic appearance is highly important 3-splinting of anterior teeth bridge retainer(8) (9) Alteration of lingual contour of maxillary teeth Protection of incisal edge of anterior teeth in case of attrition   Contraindications :   1-Young patients with large pulp 2-poor oral hygiene ,multiple caries 3-non vital teeth 4- thin tooth ( narrow labiolingual diamention )

32. Advantages : conservative minimum gingival involvement adequate retention accessibility for finishing and hygiene   disadvantages: less retention than complete coverage technically demanding not useble on nonvital teeth

33. (2-1)- maxillary canine 3\4 crown 1-placment of guiding groove on the lingual surface Use : round ended diamond Depth :1mm

34. 2- lingual surface reduction Clearance is verified before reduction of the other half. Use : football-shaped diamond Depth :1mm

35. incisal bevel. No significant change has occurred in the incisocervical height. Use : round ended diamond Depth : 0.7 mm

36. 4-Axial reduction ( lingual chamfer margin) Use : teperd tungsten carbide fissre bur

37. 5-retention forms Proximal grooves and lingual pinhole Use : Fine –grit tapered diamonds or tungsten carbide bur 5-retention forms Proximal grooves and lingual pinhole Use : Fine –grit tapered diamonds or tungsten carbide bur

38. The pinhole is prepared stages : 1- A small horizontal ledge Use : large , tapered or cylindrical tungsten carbide bur 2- a slight dimple is created (Indentations) Use : small round bur at the intended pinhole location;

39. 3- preparation pilot hole Use : small-diameter twist drill* (it must be parallel to the precise path of placement of the restoration ) 4- the preparation is completed with a tapered tungsten carbide bur to a pinhole depth of approximately 2 mm;

40. 4-Indentations: . left and right sides of the incisal ledge and center in the cervical ledge use : small, round bur  

41. (2-2)- maxillary central incisor pinledge : 1-Guiding grooves on lingual surface Use : round ended diamond Depth : 1mm 2-lingual reduction , placement of incisal bevel Use : football-shaped diamond Depth :1mm

42. 3-Incisal and cervical ledges Prepare two ledges use : a cylindrical tungsten carbide bur. Recommended minimum ledge width is 0.7 mm

43. 5-preparation of Pinholes depth of 2 mm ( pinholes will be in sound dentin ) Use ; tapered tungsten carbide bur

44.   INLAYS AND ONLAYS Materials : Cast metals high gold alloys low gold alloys palladium silver alloys base metal alloys Tooth colored 1-Porcelain 2-composite  

45. Indications : onlay inlay 1- carious teeth with intact buccal and lingual cusps 2- Need to replace MOD amalgam 3- Low caries rate 4- Patient’s request for gold instead of amalgam 1-Small carious lesion 2- remaining dentin Adequate for support 3- Low caries rate 4- Patient’s request for gold instead of amalgam or composite resin

46. Contraindications: onlay inlay 1- Extensive caries 2- Poor plaque control 3- Short clinical crown or extruded teeth 4-Lesions extending beyond transitional line angles 1- Extensive caries 2- Poor oral hygiene 3- Small teeth 4- young patient 5- Poor dentinal support

47. Advantages : onlay inlay 1- Support of cusps 2-High strength + Same advantages of inlay 1- Superior material properties 2- Longevity 3-No discoloration from corrosion 4- Least complex cast restoration

48. Disadvantages : onlay inlay 1- Lacks retention + Same disadvantages of inlay 1- Less conservation of tooth structure than amalgam 2- May display metal 3- Gingival extension beyond ideal

49. Preparation : :   a- Mesio - occlusal or Distal- occlusal Inlay Preparation   b- Mesio - occlusal –distal Onlay Preparation

50. a- Mesio - occlusal or Distal- occlusal Inlay Preparation Outline Form : Occlusal preparation   - Penetrate the central groove in 3 points just depth of the dentin : (typically about 1.8 mm) use : tapered tungsten carbide bur   - connect between points - use : tapered tungsten carbide bur   - extend the outline proximally ,then layer of enamel should remain between the side of the bur and the adjacent

51. - box preparation width of the gingival floor : (1 mm mesiodistally ) Use : tapered tungsten carbide bur

52. - caries excavation : Use : excavator , round bur in the low speed   - axiogingival groove and bevel placement - groove at junction of axial and gingival walls  enhance resistance form , and prevent distortion of the wax pattern during manipulation Use : GMT

53. - bevels :  provide strength and durability  place 45 degree gingival margin bevel , 0.8 mm wide  proximal bevels on buccal and lingual walls  occlusal bevel Use : tapered tungsten carbide bur or fine-grit diamond

54. b- Mesio - occlusal –distal Onlay Preparation (MOD) : similar to The occlusal outline and proximal boxes of an inlay ,The additional steps : 1- occlusal reduction and a 2-functional (centric) cusp ledge:

55. outline form prepare the occlusal outline ( 1.8 mm deep) use : tapered tungsten carbide bur   - prepare the boxes:   - extend the outline both mesially and distally   - caries excavation : Use : excavator , round bur in the low speed

56. - occlusal reduction -place grooves on the functional cusps (1.3 mm deep , allowing 0.2 smoothing ) -place grooves on the nonfunctional cusps ( 0.8 mm ) use : tapered tungsten carbide bur

57. -connect the grooves Use : tapered tungsten carbide bur - prepare (1.mm functional cusp ledge):  provides the restoration bulk in this high stress area ( structural durability )  1 mm apical to the opposing centric contacts , it extend to the proximal boxes Use : cylindrical tungsten carbide bur

58. margin placement :( bevels)  continues bevel on all margins  gingival bevel (45-degree)  bevels on functional(1.5mm) and nonfunctional cusps(1mm) ( for additional bulk at margins )   Use : tapered tungsten carbide bur or fine-grit diamond

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