The university of georgia

Posterior Partial Veneer Crown Preparations

Atheer Ahmed Abed 1330129

Prosthetic Dentistry II 

DEFINITION 

 A restoration that restores all but one coronal surface of a tooth, usually not covering the facial surface.

A partial veneer crown is a restoration covering two or more surfaces of a tooth

TYPES OF PARTIAL COVERAGE CROWNS 1)Three-quarter crown

2)Modified three-quarter crown 3)Seven-eighth crowns 4)proximal half crowns 

INDICATIONS FOR PARTIAL VENEER CROWNS Partial veneer crowns are a conservative measure

and are preferable to the complete veneer restoration.

Intact or minimally restored teeth.

Teeth with crown length that is average or that exceeds the average.

Teeth with normal anatomic crown form, i.e., without excessive cervical constriction. 

CONTRAINDICATIONS FOR PARTIAL VENEER CROWNS High caries rate.

Teeth with extensive restoration Deep cervical lesion difficult to establish finish line , if area is sensitive complete coverage crown is indicated

Teeth with short clinical crown – difficult to achieve resistance and retention form. Thin teeth – preparation of retention grooves is difficult. Poor alignment of teeth in the dental 

ADVANTAGES OF PARTIAL VENEER CROWNS Partial veneer crowns have several advantages over

complete crowns: The tooth reduction is conservative.

The esthetics surpass the complete veneer cast crown.

Margin accessibility for finishing and cleaning is improved.

Complete seating of the casting is more easily verified.

Complete seating of the casting during cementation is enhanced by diminished hydraulic pressure.

Electric pulp testing can be conveniently accomplished on the intact enamel surface

DISADVANTAGES OF PARTIAL VENEER CROWNS The partial veneer crown is not as retentive as a

complete veneer crown.

Skillful preparation is critical to avoid metal display.

The partial veneer crown preparation is limited to fairly intact teeth with normally shaped crown and an average length clinical crowns 

 Fundamental Principles of Design 1) To impart strength to the remaining portion of

the tooth crown. 2) To provide maximum resistance and retention form to the finished restoration. 3) To preserve esthetics by conservation of tooth structure, thus limiting the display of gold on buccal and labial surfaces

ROTARY INSTRUMENTS USED FOR TOOTH PREPARATIONS 

Round end tapered diamond, Torpedo diamond, Short needle, Long needle, Flame diamond, Small wheel diamond, Tapered fissure burs End cutting bur 

Steps for preparation of partial veneer crowns 

Outline Form Lingual reduction Incisal reduction Lingual axial reduction Proximal axial reduction Proximal box or groove placement Occlusal or incisal offset placement Facial bevel Finishing the preparation.

 Maxillary posterior three quarter crownsOcclusal reduction

1) round-end tapered diamond is used 2) Depth orientation grooves are made on the triangular ridges and the developmental grooves 1.0mm on the non functional and 1.5mm on the functional cusp 

3)At the occluso-facial line angle groove is made only 0.5mm deep to minimize the display of metal.

4)Tooth structure from between the grooves is removed according to cuspal contours

Functional Cusp Bevel 

Should be parallel to the inward facing inclines of the cusps of the opposing tooth, at depth of 1.5mm creating 45˚ angle with the axial wall

Lingual Axial Reduction

Torpedo diamond creating a definite chamfer all over. Over inclination of the lingual wall frequently occurs. Check at all times for over inclination.

Proximal Reduction 

Initially thin needle diamond is used in sawing motion to just break the contact with the adjacent tooth Once contact is broken, torpedo diamond is used to create a definite chamfer finish line and complete the axial and proximal reduction

Axial Finishing 

 Proximal Groove 

Facial bevel

Completed three quarter crown

Referance

www.google.comwww.indiandentalacademy.com 

Any question

Thank you