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- 1. TOOTH PREPARATION FOR FULL VENEER CROWNS INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
- 2. CONTENTS OF THE SEMINAR Introduction and history of full veneer crowns Terminologies Rotary Instruments used for tooth preparation Preparation for full veneer crowns a. Complete cast metal crown b. Anterior metal ceramic crown c. Posterior metal ceramic crown d. Porcelain jacket crown e. Cast ceramic crown Review of literature Conclusion References www.indiandentalacademy.com
- 3. Tooth preparation is a far more important phase of fixed partial denture prosthesis treatment although some practitioners never realize this. It must be done with skill and meticulous attention to detail, for everything else that follows – pulpal vitality, periodontal health, a good esthetic result, proper occlusion, protection of remaining tooth structure, and the longevity of the restoration itself – will depend on it. INTRODUCTION www.indiandentalacademy.com
- 4. Although fixed prosthodontic crown and bridge work dates to as back as 300 to 400 BC where in one of the oldest tombs of Sidon, a Phoenician specimen was found consisting of gold wire fastened around six anterior teeth, two of them being pontics. But crown and bridge fixed partial prosthesis was indeed in a crude state of development till as late as 1850. The early crown were not fabricated by casting. It was made by flowing solder over gold foil that had been adapted to the tooth preparation, with wrought wire staples in the preparation grooves. Inlays were made in a similar fashion by flowing solder into a foil matrix adapted to the cavity preparation. HISTORY www.indiandentalacademy.com
- 5. TOOTH PREPARATION FOR FULL VENEER CROWNS www.indiandentalacademy.com
- 6. The significance of tooth preparation grew steadily as technology made possible an increasingly accurate fit of cast restorations. With improvement in the technology of fabricating restorations, there was a tremendous increase in the complexity of restoration designs and in the demands placed on retainers by more sophisticated prostheses. During the same time period that new types of all-metal restorations were evolving, efforts were being made to produce restorations that could restore the patient esthetically as well as functionally. www.indiandentalacademy.com
- 7. A major step in this direction was the development of the porcelain jacket crown by Land in 1886 when low-fusing porcelain fused in a gold matrix made its appearance. In 1907 William H. Taggart announced his method of making gold castings, using a disappearing wax pattern. This application of an old method revolutionized the technical aspect of restorative dentistry. It made possible exceptional refinements in the construction of fixed partial prosthetic appliances. www.indiandentalacademy.com
- 8. From the beginning, restorative dental procedures have been limited far more by the technology available than by a lack of ingenuity on the art of dentists. These technological improvements have not decreased the need for skilled, knowledgeable restorative dentists. On the contrary, they have made knowledge and skill that much more critical. Technology in the hands of a skilled operator makes it possible to do more work of an even higher quality. www.indiandentalacademy.com
- 9. TERMINOLOGIESTERMINOLOGIES Tooth preparation: is defined 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) www.indiandentalacademy.com
- 10. 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) www.indiandentalacademy.com
- 11. ROTARY INSTRUMENTS USED FORROTARY INSTRUMENTS USED FOR FULL VENEER PREPARATIONSFULL 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 www.indiandentalacademy.com
- 12. Small wheel diamond 1. 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 www.indiandentalacademy.com
- 13. End cutting bur Conventional shoulder finishing Torpedo bur 1.Axial wall finishing 2.Chamfer finishing Flame bur 1. Flare and bevel finishing Tapered fissure burs (169L & 170L) 1.Initial groove alignment 2.Angles of proximal boxes 3.Smoothing and finishing 4.Occlusal and incisal bevels www.indiandentalacademy.com
- 14. TOOTH PREPARATION FOR FULL VENEER CROWNS www.indiandentalacademy.com
- 15. CONTENTS OF THE SEMINAR Introduction and history of full veneer crowns Terminologies Rotary Instruments used for tooth preparation Preparation for full veneer crowns a. Complete cast metal crown b. Anterior metal ceramic crown c. Posterior metal ceramic crown d. Porcelain jacket crown e. Cast ceramic crown Review of literature Conclusion References www.indiandentalacademy.com
- 16. Tooth preparation is a far more important phase of fixed partial denture prosthesis treatment although some practitioners never realize this. It must be done with skill and meticulous attention to detail, for everything else that follows – pulpal vitality, periodontal health, a good esthetic result, proper occlusion, protection of remaining tooth structure, and the longevity of the restoration itself – will depend on it. INTRODUCTION www.indiandentalacademy.com
- 17. Although fixed prosthodontic crown and bridge work dates to as back as 300 to 400 BC where in one of the oldest tombs of Sidon, a Phoenician specimen was found consisting of gold wire fastened around six anterior teeth, two of them being pontics. But crown and bridge fixed partial prosthesis was indeed in a crude state of development till as late as 1850. The early crown were not fabricated by casting. It was made by flowing solder over gold foil that had been adapted to the tooth preparation, with wrought wire staples in the preparation grooves. Inlays were made in a similar fashion by flowing solder into a foil matrix adapted to the cavity preparation. HISTORY www.indiandentalacademy.com
- 18. The significance of tooth preparation grew steadily as technology made possible an increasingly accurate fit of cast restorations. With improvement in the technology of fabricating restorations, there was a tremendous increase in the complexity of restoration designs and in the demands placed on retainers by more sophisticated prostheses. During the same time period that new types of all-metal restorations were evolving, efforts were being made to produce restorations that could restore the patient esthetically as well as functionally. www.indiandentalacademy.com
- 19. A major step in this direction was the development of the porcelain jacket crown by Land in 1886 when low-fusing porcelain fused in a gold matrix made its appearance. In 1907 William H. Taggart announced his method of making gold castings, using a disappearing wax pattern. This application of an old method revolutionized the technical aspect of restorative dentistry. It made possible exceptional refinements in the construction of fixed partial prosthetic appliances. www.indiandentalacademy.com
- 20. From the beginning, restorative dental procedures have been limited far more by the technology available than by a lack of ingenuity on the art of dentists. These technological improvements have not decreased the need for skilled, knowledgeable restorative dentists. On the contrary, they have made knowledge and skill that much more critical. Technology in the hands of a skilled operator makes it possible to do more work of an even higher quality. www.indiandentalacademy.com
- 21. TERMINOLOGIESTERMINOLOGIES Tooth preparation: is defined 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) www.indiandentalacademy.com
- 22. 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) www.indiandentalacademy.com
- 23. ROTARY INSTRUMENTS USED FORROTARY INSTRUMENTS USED FOR FULL VENEER PREPARATIONSFULL 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 www.indiandentalacademy.com
- 24. Small wheel diamond 1. 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 www.indiandentalacademy.com
- 25. End cutting bur Conventional shoulder finishing Torpedo bur 1.Axial wall finishing 2.Chamfer finishing Flame bur 1. Flare and bevel finishing Tapered fissure burs (169L & 170L) 1.Initial groove alignment 2.Angles of proximal boxes 3.Smoothing and finishing 4.Occlusal and incisal bevels www.indiandentalacademy.com
- 26. FULL VENEER CROWNS COMPLETE CAST CROWN ALL CERAMIC CROWN METAL CERAMIC www.indiandentalacademy.com
- 27. COMPLETE CAST METAL CROWNS Complete cast metal crowns can be used where the break down of tooth structure is severe, to the extent that is has been described in operative dentistry as “the final attempt to preserve the tooth”. The terms “full crown”, “full cast crown” and “complete crown” can be used interchangeably with full veneer crown to describe a restoration entirely made of cast metal. www.indiandentalacademy.com
- 28. Clinicians have long considered full veneer crowns to be the most retentive of veneer preparations Controlled laboratory studies have shown that 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 Instead should be used on those teeth whose restoration demands maximum retention. Selection of full veneer retainer becomes mandatory when the abutment tooth is small or when the edentulous space is long. www.indiandentalacademy.com
- 29. Indications Extensive destruction from caries or trauma. Endodontically treated teeth. Existing restoration that needs the use of a more conservative restoration Necessity for maximum retention and strength. To provide contours to receive a removable appliance. Other re-contouring of axial surfaces (minor corrections of malinclinations). Correction of occlusal plane. Contraindications Should not be used in mouths with uncontrolled caries Less than maximum retention necessary. Esthetics. www.indiandentalacademy.com
- 30. Advantages Strong. High retentive qualities. Usually easy to obtain adequate resistance form. Option to modify form and occlusion. Contact areas can be conveniently developed. Embrasure areas can be enhanced for periodontally compromised dentition. Disadvantages Removal of large amount of tooth structure. Adverse effects on tissue. Vitality testing not readily feasible. Display of metal.www.indiandentalacademy.com
- 31. Planar occlusal reduction is done using round end tapered diamond and no: 171 bur. Depth orientation grooves are made on the triangular ridges and primary developmental grooves. The depth orientation grooves should be 1.5mm deep on functional cusps and 1mm deep on non- functional cusps. The tooth structures between the orientation grooves are removed following cuspal contours. TOOTH PREPARATION FOR COMPLETE CAST CROWN www.indiandentalacademy.com
- 32. Functional cusp bevel is done using round end tapered diamond and no: 171 bur. Depth orientation grooves are placed across the facial occlusal line angle of the mandibular molar. The bevel should parallel the inward facing inclines of the cusps of the opposing tooth, at a depth of 1.5 mm usually forming a 45° angle with the axial wall. www.indiandentalacademy.com
- 33. Facial and lingual axial reduction is done with a torpedo diamond producing a definite chamfer finish line at the same time. The facial and lingual reduction are carried as far as possible into the interproximal embrasures without nicking the adjacent teeth. www.indiandentalacademy.com
- 34. TOOTH PREPARATION FOR FULL VENEER CROWNS www.indiandentalacademy.com
- 35. CONTENTS OF THE SEMINAR Introduction and history of full veneer crowns Terminologies Rotary Instruments used for tooth preparation Preparation for full veneer crowns a. Complete cast metal crown b. Anterior metal ceramic crown c. Posterior metal ceramic crown d. Porcelain jacket crown e. Cast ceramic crown Review of literature Conclusion References www.indiandentalacademy.com
- 36. Mesial and distal axial reduction. A short thin tapered diamond is placed against the facial surface of the remaining interproximal tooth structure. It is held upright and moved up and down, directing it lingually with light pressure. Once sufficient space has been produced, sweep the short thin diamond back and forth planing the surface to smoothness. www.indiandentalacademy.com
- 37. Chamfer finishing. Torpedo bur is used to produce a distinct finish line and to round of the angles of the preparation. www.indiandentalacademy.com
- 38. Seating groove is made on the axial surface using no: 171 bur. The groove should be cut to the full diameter and it should extend gingivally to a point 0.5 mm above the chamfer. www.indiandentalacademy.com
- 39. Features of full veneer crown preparation and the function served by each www.indiandentalacademy.com