Tooth preparation for full veneer crowns /certified fixed orthodontic courses by Indian dental...

TOOTH PREPARATION FOR FULL VENEER CROWNS

INDIAN DENTAL ACADEMY

Leader in continuing dental education www.indiandentalacademy.com

www.indiandentalacademy.com

CONTENTS OF THE SEMINAR

Introduction and history of full veneer crowns TerminologiesRotary Instruments used for tooth preparationPreparation for full veneer crowns

a. Complete cast metal crownb. Anterior metal ceramic crownc. Posterior metal ceramic crownd. Porcelain jacket crown e. Cast ceramic crown

Review of literatureConclusionReferences


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


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


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.


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.


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

TERMINOLOGIESTERMINOLOGIESTooth 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)


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)


ROTARY INSTRUMENTS USED FOR ROTARY INSTRUMENTS USED FOR FULL VENEER PREPARATIONSFULL VENEER PREPARATIONS

Shape Use

Round end tapered diamond

1.Depth orientation grooves2.Occlusal reduction3.Functional cusp

Torpedo diamond 1.Axial reduction2.Chamfer finish line

Short needle 1.Initial interproximal axial reduction in posterior teeth

Long needle 1.Initial proximal axial reduction in anterior teeth


Small wheel diamond 1. Lingual reduction in anterior teeth

Tapered fissure bur (171L)

1.Seating groove2.Proximal groove (posterior teeth3.Smoothing and finishing4.Occlusal and incisal bevels


End cutting bur Conventional shoulder finishing

Torpedo bur 1.Axial wall finishing2.Chamfer finishing

Flame bur 1. Flare and bevel finishing

Tapered fissure burs (169L & 170L)

1.Initial groove alignment2.Angles of proximal boxes3.Smoothing and finishing4.Occlusal and incisal bevels
