322441307-tooth-preparation-for-composite-ppt.ppt
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322441307-tooth-preparation-for-composite-ppt.ppt
- 1. Tooth preparation for Tooth preparation for Composite restoration Composite restoration
- 2. TOOTH PREPARATION FOR TOOTH PREPARATION FOR COMPOSITES COMPOSITES DEFINITION: Tooth preparation is DEFINITION: Tooth preparation is defined as the mechanical alteration of a defined as the mechanical alteration of a defective, injured or diseased tooth to defective, injured or diseased tooth to best receive a restorative material that best receive a restorative material that will reestablish a healthy state for the will reestablish a healthy state for the tooth, including aesthetic corrections tooth, including aesthetic corrections where indicated along with normal form where indicated along with normal form and function. and function.
- 3. STAGES AND STEPS OF TOOTH PREPARATION STAGES AND STEPS OF TOOTH PREPARATION INITIAL TOOTH PREPARATION STAGES INITIAL TOOTH PREPARATION STAGES 1. 1. Outline form and initial depth. Outline form and initial depth. 2. 2. Primary resistance form. Primary resistance form. 3. 3. Primary retention form. Primary retention form. 4. 4. Convenience form. Convenience form. FINAL TOOTH PREPARATION STAGES FINAL TOOTH PREPARATION STAGES 5. Removal of any remaining infected dentin, or old 5. Removal of any remaining infected dentin, or old restorative material, if indicated. restorative material, if indicated. 6. Pulp protection, if needed. 6. Pulp protection, if needed. 7. Secondary resistance and retention forms. 7. Secondary resistance and retention forms. 8. Procedure for finishing external walls. 8. Procedure for finishing external walls. 9. Final procedures: cleaning , inspecting and sealing. 9. Final procedures: cleaning , inspecting and sealing.
- 4. Burs Burs ADA size ADA size no no Head Head diameter diameter Head Head length length Taper Taper angle angle shape shape ¼ ¼ 0.50 0.50 0.40 0.40 - - Round Round ½ ½ 0.60 0.60 0.48 0.48 - - Round Round 2 2 1.00 1.00 0.80 0.80 - - Round Round 4 4 1.40 1.40 1.10 1.10 - - round round 169L 169L 0.90 0.90 5.6 5.6 4 4 Elongated Elongated taper taper 330L 330L 0.80 0.80 3 3 4 4 Pear long Pear long Mirror ,Explorer & periodontal probe, Chisels, Hatchet, Gingival marginal trimmer , Excavators, High & low speed hand piece
- 5. Tooth preparation for composites Tooth preparation for composites includes some basic principles like- includes some basic principles like- Removing the fault,defect,old restoration, or Removing the fault,defect,old restoration, or friable tooth structure friable tooth structure Creating prepared enamel margin of 90 Creating prepared enamel margin of 90 degree or greater degree or greater Creating 90 degree butt joint on cavosurface Creating 90 degree butt joint on cavosurface margin on root surface. margin on root surface. Roughening the prepared tooth structure Roughening the prepared tooth structure with a diamond stone. with a diamond stone.
- 6. Objectives Objectives Less outline extension Less outline extension Axial or pulpal wall of varying depth(not Axial or pulpal wall of varying depth(not uniform) uniform) Incorporation of bevels. Incorporation of bevels. Preparation walls being rough. Preparation walls being rough. Use of diamond stone to increase the Use of diamond stone to increase the roughness. roughness.
- 7. Types of composites preparation Types of composites preparation Conventional Conventional Bevelled conventional Bevelled conventional Modified Modified Box only Box only Slot preparation Slot preparation
- 8. Conventional Conventional Indication Indication Preparation located on the root surface(non enamel areas). Preparation located on the root surface(non enamel areas). Moderate to large class 1 or class 2 restoration Moderate to large class 1 or class 2 restoration Conventional tooth preparation are those typical for Conventional tooth preparation are those typical for amalgam restoration. amalgam restoration. An inverted cone no. 245 bur is used to prepare the An inverted cone no. 245 bur is used to prepare the tooth resulting in preparation design similar to that tooth resulting in preparation design similar to that for amalgam but smaller in width and extension. for amalgam but smaller in width and extension.
- 9. Bevelled conventional Bevelled conventional They are tooth preparation which is They are tooth preparation which is similar to conventional preparation in similar to conventional preparation in that the outline form has external box that the outline form has external box like wall but with some bevelled enamel like wall but with some bevelled enamel margin. margin. Indication Indication to replace an existing restoration (amalgam) to replace an existing restoration (amalgam) exhibiting a conventional tooth preparation exhibiting a conventional tooth preparation design with enamel margin or to restore a large design with enamel margin or to restore a large area. area.
- 10. Beveling Beveling Increase the surface area for bonding Increase the surface area for bonding Reduces the marginal leakage. Reduces the marginal leakage. Types of bevels Partial bevel : This should involve about 1/3 to ½ of the enamel wall at 45-70 degree to the cavity. Long bevel : the entire enamel wall is bevelled at at 45-70 degree to the cavity wall Hollow ground bevel : about two thirds of the enamel wall thickness is ground in concave manner so the cavity margin will have right angled cavosurface angle with butt joint between the restorative material and the enamel margin. Scalloping the margin : this feature can be used in conjunction with a partial or long bevel, in order to further increase the surface area and irregularities of the enamel that is conditioned. Skirting : this feature is used if conditioned enamel will be the main retentive mode for resinious material .
- 11. Cavity designs for composites resins Cavity designs for composites resins Based on the dye penetration test and the Based on the dye penetration test and the quantitative analysis of the micromorphplogy quantitative analysis of the micromorphplogy of the margin adaptation, the experimental of the margin adaptation, the experimental cavity and cavity and cavities with a long bevel showed cavities with a long bevel showed better margins than cavities with right- better margins than cavities with right- angled butt joints or cavities with concave angled butt joints or cavities with concave bevels bevels. . A Porte.F Lutz et al; operative dentistry, 1983
- 12. Modified Modified They are They are indicated indicated for the initial restoration of smaller for the initial restoration of smaller cavitated ,carious lesion usually surrounded by cavitated ,carious lesion usually surrounded by enamel and for correcting the enamel defect. enamel and for correcting the enamel defect. Objectives of this preparation design are to remove Objectives of this preparation design are to remove the fault as conservatively as possible. preparation the fault as conservatively as possible. preparation appears to have appears to have “scooped out” “scooped out” rather than distinct rather than distinct internal line angles. internal line angles. Box only Box only This design is indicated only when the proximal This design is indicated only when the proximal surface is faulty with no lesion present on the occlusal surface is faulty with no lesion present on the occlusal surface surface. .
- 13. Facial / lingual slot Facial / lingual slot In this case the lesion is detected on the In this case the lesion is detected on the proximal surface but the operator proximal surface but the operator believes that access to the lesion can be believes that access to the lesion can be obtained from either a facial or lingual obtained from either a facial or lingual direction rather than through marginal direction rather than through marginal ridge from an occlusal direction. ridge from an occlusal direction.
- 14. Class 3 tooth preparation Class 3 tooth preparation When proximal surface of an anterior tooth to When proximal surface of an anterior tooth to be restored ,there is a choice between facial be restored ,there is a choice between facial or lingual entry into the tooth. or lingual entry into the tooth. Advantages from lingual approach Advantages from lingual approach facial enamel is conserved for enhanced facial enamel is conserved for enhanced esthetics esthetics Some unsupported but not friable enamel may Some unsupported but not friable enamel may be left on the facial walls be left on the facial walls Color matching of composites is not critical Color matching of composites is not critical Discoloration of restoration is less visible. Discoloration of restoration is less visible.
- 15. Indication for facial approach Indication for facial approach Carious lesion is positioned facially such that Carious lesion is positioned facially such that facial access would significantly conserve facial access would significantly conserve tooth structure tooth structure Teeth irregularly aligned, making the lingual Teeth irregularly aligned, making the lingual access undesirable. access undesirable. Extensive caries extend onto the facial Extensive caries extend onto the facial surface. surface. Faulty restoration which needs to be Faulty restoration which needs to be replaced. replaced.
- 16. Tooth preparation methods Tooth preparation methods Bur size depends on the size of the lesion, mainly no.1/2, 1 or 2 size Bur size depends on the size of the lesion, mainly no.1/2, 1 or 2 size round bur or diamond , prepare the outline form on the root round bur or diamond , prepare the outline form on the root surface extending the external walls to sound tooth structure while surface extending the external walls to sound tooth structure while extending pulpally to an initial depth of 0.75mm. extending pulpally to an initial depth of 0.75mm. Initial entry penetrates the carious lesion as close to the adjacent Initial entry penetrates the carious lesion as close to the adjacent tooth without contacting it. tooth without contacting it. Cutting instruments held perpendicular to the enamel surface Cutting instruments held perpendicular to the enamel surface. .
- 17. Axial wall depth initially is limited to 0.2 mm inside Axial wall depth initially is limited to 0.2 mm inside the DEJ. the DEJ. Axial wall should be outwardly convex following Axial wall should be outwardly convex following normal external tooth contour and DEJ. normal external tooth contour and DEJ. If preparation is on the root ,the external walls If preparation is on the root ,the external walls should be perpendicular to the root surface forming should be perpendicular to the root surface forming a 90 degree cavosurface angle. a 90 degree cavosurface angle. Gingival retention groove-prepare this groove appox Gingival retention groove-prepare this groove appox 0.2 mm inside DEJ to a depth of 0.25mm (half the 0.2 mm inside DEJ to a depth of 0.25mm (half the diameter of no.1/4 bur). diameter of no.1/4 bur). The depth wise direction of the groove is an angle The depth wise direction of the groove is an angle that bisect the junction of axial wall and external that bisect the junction of axial wall and external walls. walls.
- 18. Incisal retention cove - no.1/4 bur is Incisal retention cove - no.1/4 bur is used at the axioincisal point angle with used at the axioincisal point angle with the bur oriented in similar angle ,0.2 the bur oriented in similar angle ,0.2 mm inside DEJ and 0.25 mm depth. then mm inside DEJ and 0.25 mm depth. then extend it slightly into the facioaxial line extend it slightly into the facioaxial line angle where it fades out. angle where it fades out. Cavosurface bevel or flare is best Cavosurface bevel or flare is best prepared with either a flame shaped or prepared with either a flame shaped or round diamond instrument resulting in round diamond instrument resulting in an angle appox 45 degree to the an angle appox 45 degree to the external tooth surface. A bevel width of external tooth surface. A bevel width of 0.25 to 0.5 mm is considered sufficient 0.25 to 0.5 mm is considered sufficient. .
- 19. Facial access same as the lingual ,the Facial access same as the lingual ,the procedure is simplified because of direct procedure is simplified because of direct vision. vision. Final tooth preparation accomplished by Final tooth preparation accomplished by removing any remaining dentin with a removing any remaining dentin with a round bur rotating at low speed or a spoon round bur rotating at low speed or a spoon excavator. excavator. Outline form should Outline form should not include not include Entire proximal contact area Entire proximal contact area Extend onto the facial surface Extend onto the facial surface Extended subgingivally Extended subgingivally
- 20. Class 4 composite restoration Class 4 composite restoration Conventional preparation has Conventional preparation has minimal clinical class 4 minimal clinical class 4 application except in those areas application except in those areas that have margins located on root that have margins located on root surface. surface. In addition to the etched In addition to the etched enamel ,retention of composites enamel ,retention of composites restoration material in bevelled restoration material in bevelled conventional class 4 preparation conventional class 4 preparation may be obtained by groove or may be obtained by groove or other shaped undercuts, dovetail other shaped undercuts, dovetail extension ,threaded pins. extension ,threaded pins.
- 21. Dovetail extension into the lingual surface Dovetail extension into the lingual surface of the tooth may enhance both the of the tooth may enhance both the restoration strength and retention but it is restoration strength and retention but it is less conservative and therefore not used. less conservative and therefore not used. Pin retention discouraged Pin retention discouraged risk of perforation into pulp or external risk of perforation into pulp or external surface. surface. Pins do not enhance the strength of Pins do not enhance the strength of restorative material restorative material Some pins corrode due to microlekage Some pins corrode due to microlekage resulting in discoloration. resulting in discoloration.
- 22. Appropriate size round carbide / Appropriate size round carbide / diamond at high speed with air water diamond at high speed with air water coolant prepare outline form. coolant prepare outline form. Remove all weakened enamel and Remove all weakened enamel and establish the initial axial wall depth at establish the initial axial wall depth at 0.5mm in dentin 0.5mm in dentin Bevel width 0.25 – 2 mm Bevel width 0.25 – 2 mm Gingival retention groove given. Gingival retention groove given.
- 23. Class 4 preparation and a pin channel placed Class 4 preparation and a pin channel placed into the dentin 1 mm from the dentino- into the dentin 1 mm from the dentino- enamel junction using a #330 bur with a high enamel junction using a #330 bur with a high speed hand piece with water spray. speed hand piece with water spray. The resultant pin channel was appox 0.8 mm The resultant pin channel was appox 0.8 mm in diameter by 1.00 mm deep. in diameter by 1.00 mm deep. The mean fracture load of teeth with the The mean fracture load of teeth with the resin composite pin channel was significantly resin composite pin channel was significantly greater than that of the teeth without pin. greater than that of the teeth without pin. HW Roberts et al ;operative dentistry, 2000, 25,270-273
- 24. Class 5 composite restoration Class 5 composite restoration Located in the gingival 1/3 of the Located in the gingival 1/3 of the facial and lingual tooth surface. facial and lingual tooth surface. Tapered fissure carbide bur Tapered fissure carbide bur (no.700,701,271) or similarly (no.700,701,271) or similarly shaped diamond is used along shaped diamond is used along with air water spray with air water spray Entry at 45 degree angle to the Entry at 45 degree angle to the tooth surface tooth surface As the cutting progress maintain As the cutting progress maintain the burs long axis perpendicular the burs long axis perpendicular to the external surface of the to the external surface of the tooth during preparation of the tooth during preparation of the outline form which would result outline form which would result in 90 degree cavosurface margin. in 90 degree cavosurface margin.
- 25. 0.75 axial wall depth will provide 0.75 axial wall depth will provide adequate external wall width for adequate external wall width for Strength of the preparation wall Strength of the preparation wall Placement of a retention groove Placement of a retention groove Strength of the composite Strength of the composite Axial wall should follow the contour of the facial surface which is convex outwardly mesiodistally. Final tooth preparation – remove remaining infected dentin/old restorative material _ apply calcium hydroxide -- prepare groove retention form
- 26. Class 1 composite restoration Class 1 composite restoration Conventional preparation- enter Conventional preparation- enter the tooth in the distal pit area of the tooth in the distal pit area of the faulty occlusal surface with the the faulty occlusal surface with the inverted cone diamond positioned inverted cone diamond positioned parallel to the long axis of the parallel to the long axis of the crown. crown. Prepare the pulpal floor to an initial Prepare the pulpal floor to an initial depth of 1.5 mm as measured from depth of 1.5 mm as measured from the central groove. the central groove. Facial and lingual measurement is Facial and lingual measurement is 1.75mm which depends on the 1.75mm which depends on the steepness of the cuspal inclines steepness of the cuspal inclines
- 27. Initial depth 0.2mm inside the DEJ Initial depth 0.2mm inside the DEJ Facial ,lingual,extention and width are dictated by Facial ,lingual,extention and width are dictated by the caries ,old restorative material. the caries ,old restorative material. Extension into marginal ridge should result in Extension into marginal ridge should result in appox 1.6mm thickness of remaining tooth appox 1.6mm thickness of remaining tooth structure for premolar and 2mm for molars. structure for premolar and 2mm for molars. Pulpal floor should be flat and follow the rise and Pulpal floor should be flat and follow the rise and fall of the DEJ. fall of the DEJ. Final cavity procedure are carried out Final cavity procedure are carried out. .
- 28. Beveling on the occlusal margin may result in thin Beveling on the occlusal margin may result in thin composites where heavy occlusal force are being composites where heavy occlusal force are being acted upon. acted upon. Convergence of the occlusal wall Convergence of the occlusal wall Marginal form of the groove extension on the facial Marginal form of the groove extension on the facial or lingual surface may be beveled with the diamond or lingual surface may be beveled with the diamond resulting in a 0.25-0.5mm width bevel at a 45 degree resulting in a 0.25-0.5mm width bevel at a 45 degree angle to prepared wall. angle to prepared wall.
- 29. Class 2 composite restoration Class 2 composite restoration No.330 or 245 shaped diamond is used to No.330 or 245 shaped diamond is used to enter faulty pit opposite the proximal surface. enter faulty pit opposite the proximal surface. Diamond positioned parallel to the long axis Diamond positioned parallel to the long axis of the tooth. of the tooth. Pulpal depth 1.5mm as measured from the Pulpal depth 1.5mm as measured from the central groove. central groove. Facio-lingual width should be as narrow as Facio-lingual width should be as narrow as possible possible Pulpal floor should is relatively flat Pulpal floor should is relatively flat
- 30. Occlusal wall generally converge occlusally because of Occlusal wall generally converge occlusally because of the inverted shape of the diamond. the inverted shape of the diamond. Proximal box – once the diamond has extended through Proximal box – once the diamond has extended through the marginal ridge ,care should be taken not to cut the the marginal ridge ,care should be taken not to cut the adjacent tooth. adjacent tooth. Proximal ditch cut is initiated – hold the diamond over Proximal ditch cut is initiated – hold the diamond over the DEJ with tip directed gingivally - cut that will be 0.2 the DEJ with tip directed gingivally - cut that will be 0.2 mm inside the DEJ mm inside the DEJ. .
- 31. For a no. 245 diamond instrument with a tip diameter of For a no. 245 diamond instrument with a tip diameter of 0.8mm this would require 1/4 0.8mm this would require 1/4th th of the diamond tip of the diamond tip positioned over the side of the DEJ and other 3/4 positioned over the side of the DEJ and other 3/4th th of the of the tip over the enamel. tip over the enamel. Diamond extended facially,lingually, gingivally to include Diamond extended facially,lingually, gingivally to include all the fault ,caries and old material. all the fault ,caries and old material. Occlusal wall- converge occlusally Occlusal wall- converge occlusally Proximal wall – may be parallel or convergent occlusally. Proximal wall – may be parallel or convergent occlusally.
- 32. Modified class 2 tooth Modified class 2 tooth preparation preparation Small round or inverted cone diamond may Small round or inverted cone diamond may be used for this preparation to scoop out the be used for this preparation to scoop out the carious or faulty material. carious or faulty material. Pulpal floor and the axial depth are dictated Pulpal floor and the axial depth are dictated only by the depth of the lesion. only by the depth of the lesion.
- 33. Axial wall extension onto the root surface – if caries is found below CEJ the axial wall is prepared with diamond in same axis but the diamond is tilted toward adjacent tooth to create approximate 0.75 to 1 mm axial wall depth on root surface.
- 34. COMPOSITE VENEERS COMPOSITE VENEERS These can be placed either directly or indirectly These can be placed either directly or indirectly 3 basic preparation designs exist 3 basic preparation designs exist a window preparation without extension sub- a window preparation without extension sub- gingivally or involving incisal angle gingivally or involving incisal angle window preparation that extends to gingival crest and window preparation that extends to gingival crest and terminates at the facio-incisal angle. terminates at the facio-incisal angle. veneers with incisal overlapping with sub-gingival veneers with incisal overlapping with sub-gingival extension extension
- 35. Three basic designs Three basic designs
- 36. window preparation design is recommended for window preparation design is recommended for most direct and indirect composite veneers. most direct and indirect composite veneers. such a preparation, preserves tooth structure, such a preparation, preserves tooth structure, prevent significant occlusal loading and reduced prevent significant occlusal loading and reduced potential for wear of opposing tooth. potential for wear of opposing tooth. an incisal overlapping preparation is indicated an incisal overlapping preparation is indicated when an tooth being restored needs lengthening when an tooth being restored needs lengthening or when an incisal defect warrants restoration. or when an incisal defect warrants restoration.
- 37. DIRECT COMPOSITE VENEERS DIRECT COMPOSITE VENEERS The outline is dictated solely The outline is dictated solely by the extent of the defect by the extent of the defect and should include all and should include all discolored areas. discolored areas. Using a coarse ,elliptical or Using a coarse ,elliptical or round diamond bur a depth round diamond bur a depth of about 0.5 to 0.75 mm is of about 0.5 to 0.75 mm is prepared. prepared. Usually it is not necessary to Usually it is not necessary to remove all discolored remove all discolored enamel but it should be enamel but it should be extended to sound, extended to sound, unaffected enamel. unaffected enamel.
- 38. Difference between tooth colored Difference between tooth colored composites and the gold inlays composites and the gold inlays or onlays or onlays The tooth preparation walls must be The tooth preparation walls must be more divergent than those commonly more divergent than those commonly used with alloys. used with alloys. Bevels are not present on inlay occlusal Bevels are not present on inlay occlusal surfaces. surfaces. Bevels may be present on the proximal Bevels may be present on the proximal box forms of inlay or onlay. box forms of inlay or onlay. Bevels may or may not be necessary on Bevels may or may not be necessary on the gingival areas. the gingival areas. Gordon J .Christensen et al esthetic dentistry JADA 1988
- 39. Onlay preparation may have bevel present on Onlay preparation may have bevel present on the nonstress-bearing facial and lingual the nonstress-bearing facial and lingual surface to provide better esthetics surface to provide better esthetics appearance by blending colors, and appearance by blending colors, and additional retention because of more enamel additional retention because of more enamel surface available for etching. surface available for etching. Box forms may present but rounded internal Box forms may present but rounded internal forms are better than sharp or square box forms are better than sharp or square box forms. forms. Groves are to be avoided if possible. Groves are to be avoided if possible. Gordon J .Christensen et al esthetic dentistry JADA 1988
- 40. With regard to onlay preparation the cusps With regard to onlay preparation the cusps to be covered ,in particular functional cusps to be covered ,in particular functional cusps be reduced by 1.5mm to 2.0mm . be reduced by 1.5mm to 2.0mm . The preparation of the groove in the dentin The preparation of the groove in the dentin exposed by reducing cusps or the exposed by reducing cusps or the incorporation of the pins channel in the incorporation of the pins channel in the preparation may be desirable to limit and to preparation may be desirable to limit and to counter the substantial shear forces along the counter the substantial shear forces along the composites- tooth interface during heavy composites- tooth interface during heavy loading in particular in lateral excursion. loading in particular in lateral excursion. F J T Burke et al B D J April 6 1991