terminology of dental materials

Terminology of Dental Materials.

Dr. Md. Arifur Rahman BDS(D.U), MPH

Assistant Professor & Unit Head

North East Medical College Dental Unit

Restoration :It is a conservation work which restores the lost shape(anatomy) and function(physiology) of a natural tooth. Direct: It can be performed inside the patients mouth e.g. a filling with restorative materials

Indirect:It can be made outside the patient’s mouth and then cemented in place e.g. an inlay , a crown, an onlay, or a fixed bridge.

It is fixed in nature and patient cannot remove it.

Figure of Restoration

Appliance :It is an artificial technique by which replacement of missing teeth are carried out for proper speech, masticatory function of an individual (e.g. complete and partial dentures and removable bridge ) or by which malaligned teeth are treated ( e.g. removable orthodontic appliance or fixed orthodontic appliance which is removed after the treatment).

Figure of Appliance A. Complete Denture: B. Partial Denture:

C. Orthodontic appliance

Crown :

It is a fixed restoration for the entire or major part of coronal (crown) portion of a natural tooth. It may be metallic ( gold , Stainless Steel crown) or non-metallic (acrylic jacket crown, porcelain jacket crown).

Figure of Crown : Crown:

Bridge

It is a replacement for a missing tooth or teeth . The two teeth adjacent to the space are called abutments and they are to be prepared for restorations (crown) to support the artificial tooth which is called pontic. The restorations are cemented on the abutments.

Preparation of bridge

Figure of Bridge

Partial Denture

It is a prosthetic appliance which is used to replace one or a number of tooth but not all, of the natural teeth and their supporting structures is called a partial denture.Partial denture can be constructed by two materials: (1) Metallic: ( Gold alloys, Cobalt-chromium alloys CO-Cr, Silver-palladium alloys). (2) Non-metallic: HCAR, SCAR.

Parts of Partial Denture (1) Base or saddle : It is that part

of the denture which rests on the soft tissues covering the bony ridge and to which the artificial teeth are attached. It gives support and some direct retention to the denture.

(2) Connectors: These are those parts of a denture which join other components (usually saddles) to each other.They give support and indirect retention to the denture.

Parts of Partial Denture (Cont..)

(3). Clasps: This are the metal projections of a partial denture that partially surround or contact abutment teeth. They give direct retention to the denture.

(4) Rests: These are the metallic or acrylic extensions from the partial denture that provide support by preventing tissue wards movement of the denture.

(5) Artificial teeth

Partial Denture

Clasps Figure:

Important Definition Complete Denture : It is a prosthetic

appliance which is used to replace all of the missing natural teeth.Types : 1. Non-metallic (acrylic resin). 2. Metallic Denture.

Important Definition (Cont..) Flow : Flow is the deformation of an amorphous

materials due to external force. Viscosity : It is the property of a fluid that resists the

force tending to cause the fluid to flow. It is due to internal frictional force within the liquid.

Onlay: An onlay is a dental restoration for an individual tooth that is cemented on to the surface of a tooth in contrast to an inlay that is being cemented into a prepared cavity in the tooth. It is made of cast gold alloy and is used primarily for mesio occluso-distal coverage of posterior teeth.

Important Definition (Cont..) Adhesion: It is the molecular force of attraction

between two dissimilar body. Cohesion : It is the molecular force of attraction

between two similar body. Tarnishing: It means loss of brightness of the

metal surface. So tarnish affects the metal surface and it is due to discolouration caused by chemical changes. It does not affect the structure of the metal.

Corrosion: It means the attacking of the surface of the metals by some medium in close contact with it and in course of time, the structure of the metal may be completely disintegrated resulting weakening of the material.