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full veneer tooth preparation principals and steps
The document discusses the process of tooth preparation for full veneer crowns, defining key terms and concepts such as retention and resistance forms, various crown types, and the importance of specific measurements for tooth reduction. It outlines indications and contraindications for using full veneer crowns, along with advantages, disadvantages, and necessary armamentarium for the preparation process. Additionally, it reviews literature on retention factors related to different crown preparation techniques and provides references for further reading.
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full veneer tooth preparation principals and steps
- 2. 1. INTRODUCTION 2. DEFINITION 3.INDICATIONS AND CONTRAINDICATIONS 4. ADVANTAGES AND DISADVANTAGES 5. SPECIAL FEATURES 6. ARMAMENTARIUM 7. PREPARATION 8. METAL CERAMIC CROWN 9. ALL CERAMIC CROWN 10. REVIEW OF LITERATURE 11. REFERENCES CONTENTS
- 3. TERMINOLOGIES Tooth preparation: isdefined as the mechanical treatment of dental disease or injury to hard tissues that restores a tooth to original form. (Tylman) Crown / artificial crown: a metal, plastic, or ceramic restoration that covers three or more axial surfaces and the occlusal surface or incisal edge of a tooth (GPT-7; 1999) Full veneer crown / Complete crown: A restoration that covers all the coronal tooth surfaces ( mesial, distal, facial, lingual and occlusal ) (GPT-7; 1999) Chamfer Finish line: A finish line design for tooth preparation in which the gingival aspect meets the external axial surface at an obtuse angle (GPT-7; 1999) Shoulder finish line : A finish line design for tooth preparation in which the gingival floor meets the external axial surfaces at approximately a right angle(GPT-7; 1999)
- 4. Retention form :The feature of a tooth preparation that resists dislodgement of crown in a vertical direction or along the path of placement (GPT-7; 1999) Resistance form : The features of a tooth preparation that enhance the stability of a restoration and resist dislodgement along an axis other than the path of placement (GPT-7; 1999) Bevel : The process of slanting the finish line and curve of a tooth preparation (GPT-7; 1999)
- 5. FULL VENEER CROWNS COMPLETE CAST CROWN ALLCERAMIC CROWN METAL CERAMIC
- 6. Clinicians have long consideredfull veneer crowns to be the most retentive of veneer preparations when compared with partial veneer designs, the full veneer crown exhibits superior retention and resistance It does not mean that it must be used in every case FULL CAST METAL CROWN
- 8. • teeth thatexhibit extensive coronal destruction by caries or trauma • the restoration of choice whenever maximum retention and resistance are needed • short clinical crowns or when high displacement forces are anticipated, such as for the retainer of a long-span FPD • used to support a removable partial denture, • indicated on endodontically treated teeth. • Correction of occlusal plane. INDICATION;
- 9. Extensive decayed Longspan fpd
- 10.
- 11. Crown to supportrpd Endodontically treated teeth
- 12. • should notbe used in mouths with uncontrolled caries. • Less than maximum retention necessary. • Esthetics. • Wherever an intact buccal or lingual wall exists. • if less than maximum retention and resistance are needed (e.g., on a short-span fixed partial denture. CONTRAINDICATION;
- 13. • greater retention. •Also has greater resistance form • strength of a complete cast crown is superior • this restoration is less easily deformed than its counterparts, • allows the operator to modify axial tooth contour. • easy- modification ^the occlusion ADVANTAGES;
- 14. Removal of largeamount of tooth structure. Adverse effects on tissue. Vitality testing not readily feasible. Display of metal. DISADVANTAGES;
- 15. ROTARY INSTRUMENTS USEDFOR FULL VENEER PREPARATIONS Shape Use Round end tapered diamond 1.Depth orientation grooves 2.Occlusal reduction 3.Functional cusp Torpedo diamond 1.Axial reduction 2.Chamfer finish line Short needle 1.Initial interproximal axial reduction in posterior teeth Long needle 1.Initial proximal axial reduction in anterior teeth
- 16. Small wheel diamond1. Lingual reduction in anterior teeth Tapered fissure bur (171L) 1.Seating groove 2.Proximal groove (posterior teeth 3.Smoothing and finishing 4.Occlusal and incisal bevels
- 17. Occlusal guiding grooves Occlusalreduction Axial alignment grooves Axial reduction Finishing and evaluation Armamentarium PREPARATION;
- 18. • with occlusalreduction, -1.5mm of clearance on the functional cusps and 1.0mm on the non functional cusps. • occlusal reduction should follow normal anatomic contours • Axial reduction should parallel the long axis of the tooth -6 degree taper • The margins -chamfer -supragingivally • The chamfer should be smooth and distinct and allow for 0.5mm of metal thickness at the margins CRITERIA;
- 19. • Functional (Centric)Cusp Bevel- give 1.5 mm of occlusal clearance),bevel must be angled flatter than the external surface • placed at about_45 degrees to the long axis. • Nonfunctional (Noncentric) Cusp Bevel -A minimum of 0.6 mm clearance • Chamfer Width -(minimum 0.5 mm) is important for • developing optimum axial contour. SPECIAL CONSIDERATIONS;
- 20. Use round-end tapereddiamond to make depth orientation grooves on the triangular ridges and in the primary developmental grooves Occlusal Reduction
- 21. Guiding groove forocclusal reduction; 1.place depth holes approximately 1 mm deep in the central, mesial, and distal fossae and connect them 2.place guiding grooves in the buccal and lingual developmental grooves and in each triangular ridge extending from cusp tip to center of its base. 3.because the centric or functional cusp is to be protected by an adequate thickness of metal ,place a functional cusp bevel. 4.use the guiding grooves to ensure that occlusal reduction follows anatomic configuration. A groove should be placed in the low point and high point of each cusp.low point are the central and development grooves,high point are the cusp tips and triangular ridges.
- 22. ROUND END TAPEREDdiamond is used. Complete the occlusal reduction in 2 steps. Half the occlusal surface is reduced first so that the other half can be maintained as reference. The clearance must be checked in all excursive movements . The patient should close into several layers of dark colored utility wax in maximum intercuspation. OCCLUSAL REDUCTION;
- 23. 1.5mm deep onfunctional cusp and 1.0mm deep on the nonfunctional cusps Occlusal Reduction
- 24. Enamel chisel usedto precisely judge the depth of grooves Occlusal Reduction
- 25. Removal of toothstructure between the grooves in an inclined manner Occlusal Reduction
- 26. Planar occlusal reduction: round-end tapered diamond and no.171 bur Occlusal Reduction
- 27. Functional cusp bevel: round-end tapered diamond and no.171 bur Occlusal Reduction
- 28. Checking the occlusalclearance with utility wax Occlusal Reduction
- 29. Examining the imprintof the occlusal surface Occlusal Reduction
- 30. Placement of depthorientation groove for Axial Reduction
- 31. Axial reduction; Grooves- Onein center and one in each mesial and distal line angle. 1.when these guiding grooves are placed be sure the shank of the diamond is parallel to proposed path of withdrawal of the restoration. 2.do not let the diamond cut into the tooth beyond its midpoint.
- 32.
- 33. Facial and lingualaxial reduction : torpedo diamond Axial Reduction
- 34. Buccal surface reducedwith a torpedo diamond the chamfer finish line is created at the same line Axial Reduction
- 35. The facial axialreduction is carried as far as possible into interproximal embrasures without nicking the adjacent teeth Axial Reduction
- 36. Lingual axial reductionwith the same diamond Axial Reduction
- 37. The lingual axialreduction also extends as far interproximally as can be easily accomplished Axial Reduction
- 38. An occlusal viewof the tooth preparation at this stage reveals isolated areas of intact tooth structure surrounding each proximal contact Occlusal view
- 39. Short thin needlediamond is placed against the remaining island of tooth structure and moved in a up and down motion Proximal Reduction
- 40. In tight areassometimes the tip may be used Proximal Reduction
- 41. Gaining access bysweeping the short thin diamond Proximal Reduction
- 42. Repeating the processon the opposite proximal surface Proximal Reduction
- 43. Increasing the depthof reduction and producing a finish line with torpedo Proximal Reduction
- 44. Critical area ofpreparation Proximal Reduction
- 45. More reduction achievedin this area Proximal Reduction
- 46. Chamfer finishing :torpedo bur Axial Reduction
- 47. Placement of seatinggroove 0.5mm above chamfer Axial Reduction
- 48. The completed fullveneer crown preparation
- 49. The features ofa full veneer crown preparation and the function served by each Completed Preparation
- 51. Maxillary premolar,maxillary firstmolars, mandibular first premolar,are - appearance zone. SAME AS FULL METAL EXCEPT PLACES WHERE CERAMICVENEER. PREPARATION;
- 52. Facial Index preparedin putty silicone. Facial Index
- 53. Cutting it Facio- lingually Facial Index
- 54. Facial half ofIndex Facial Index
- 55. Planar occlusal reduction: round-end tapered diamond and no.171 bur. Occlusal Reduction
- 56. Placement of depthorientation grooves 1.5MM TO 2MM Occlusal Reduction
- 57. Removal of toothmaterial between grooves Occlusal Reduction
- 58. Functional cusp bevel: round-end tapered diamond and no.171 bur Occlusal Reduction
- 59. Orientation grooves forfunctional cusp bevel FUNCTIONAL CUSP BEVEL-2MM WHERE CERAMIC IS VENEERED. Occlusal Reduction
- 60. Removal between grooves OcclusalReduction
- 61. Depth – orientationgrooves : flat-end tapered diamond 1.2mm for base metal and 1.4mm for the noble metal ceramic Facial Reduction
- 62. Aligning the burparallel to the occlusal segment of facial surface. Facial Reduction
- 63. Cutting grooves inthe occlusal portion Facial Reduction
- 64. Aligning the burin the gingival portion Facial Reduction
- 65. Cutting grooves inthe gingival portion Facial Reduction
- 66. Facial reduction, occlusalhalf : flat-end tapered diamond Facial Reduction
- 67. Occlusal segment reducedbetween grooves 1.2MM FOR BASE METAL AND 1.4 FOR NOBLE METAL Facial Reduction
- 68. Facial reduction, gingivalhalf : flat-end tapered diamond Facial Reduction
- 69.
- 70. Proximal axial reduction: short-needle diamond. Proximal Reduction
- 71. Initial reduction withshort needle diamond Proximal Reduction
- 72. Achieving Proximal Separation. Atlingual most extension of facial reduction,lingual to proximal contact-wing preparation Proximal Reduction
- 73. Needle diamond toplane the axial wall Proximal Reduction
- 74. Lingual axial reduction: torpedo diamond. Lingual Reduction
- 75. Lingual reduction withtorpedo diamond Lingual Reduction
- 76. Axial finishing : Torpedofinishing bur and no.171 bur Lingual Reduction
- 77. Finishing the axialsurface Lingual Reduction
- 78.
- 79. Rounding the lineangles and point angles Finishing
- 80. Shoulder finishing :no.957 bur. Finishing
- 81.
- 82. Smoothing the Shoulder 1MMWIDE SHOULDER FINISHED WITH RS- 1MODIFIED BIN ANGLE CHIESEL Finishing
- 83. Gingival bevel : Flamediamond and finishing bur Beveling the finish line
- 84. Flame shaped diamondto place bevel 0.3mm deep Beveling the finish line
- 85.
- 86.
- 87. Viewing facial reduction Verificationof the preparation
- 88. Viewing Overall reduction Verificationof the preparation
- 89. The features ofa preparation for PFM crown on a posterior tooth and the function served by each Completed Preparation
- 90. REVIEW OF LITERATURE; 1.David A. Felton et al (1987) found that teeth prepared for full crowns by using diamond burs will have 31% greater retention than preparations made with carbide bur. Alternative retentive features should be considered in preparation design if carbide burs are used.
- 91. 2. Shillingburg HTet al (1987) - stated that theoretically, the most retentive preparation would be with parallel walls. However in order to avoid undercuts and allow complete seating of the restorations during cementation, the walls must have some taper. One which lies within the range of 2 to 6.5 degrees has been considered to be optimal.
- 92. 3. Jeffrey Nordlanderet al (1988) studied the convergence angles of full coverage preparations performed in a clinical environment and concluded that the ideal convergence of 4 to 10 degrees is seldom achieved.The mean convergence angle of mandibular preparations were greater than mean maxillary convergence angle and premolar convergence angle tended to be smaller than anterior convergence angles.
- 93. 5. Mohammed F.Ayad et al (1997) studied the relationship between surface characteristics of teeth prepared for complete cast crowns and retention of restorative cemented restorations. Greatest retention value was for tooth preparations refined with carbide burs and cemented with Panavia-EX, an adhesive resin cement. Least retention values was for teeth preparations completed with finishing bur and luted with zinc phosphate cement.
- 94. 1.FUNDAMENTALS OF FIXEDPROSTHODONTICS-THIRD EDITION SHILLINGBURG. 2.CONTEMPORARY FIXED PROSTHODONTICS- ROSENTIEL. 3. Felton DA, Ed Kanoy B and White JT. The effect of surface roughness of crown preparations on retention of cemented castings. J Prosthet Dent. 1987; 58: 292-296. 4. Nordlander J Weir D, Stoffer W and Ochi S. The taper of clinical preparations for fixed prosthodontics. J Prosthet Dent. 1988; 60: 148-151. REFERENCES;
- 95. 5. El-Mowafy O.M.,Fenton A.H.,Forester N., Milenkovice M.-Retention of metal ceramic crowns cemented with resin cement :effects of preparation taper ,,and height – J.Prosthet.Dent 1996;76:524-29. 6. Ayad MF, Rosenteil SF and Salama M. Influence of tooth surface roughness and type of cement on retention of complete cast crowns. J Prosthet Dent. 1997; 77: 116- 121.
- 96.