Dental Waxes

variety of natural waxes and resins have been used in dentistry forspecific and well defined applications. Waxes are thermoplastic materials which are solids at room temperaturebut melt without decomposition to form mobile liquids. They consist of two ormore components which may be natural or synthetic waxes, resins, oils andpigments.

THERMAL PROPERTIES OF WAXESMELTING RANGE Waxes have a melting range rather than a melting point. Example :Paraffin 44 62 C Carnauba 50 90 C Significance: Mixing of waxes can change their melting range.

COEFFICIENT OF THERMAL EXPANSION Waxes expand when there is increase in temperature and contract when there is decrease in temp. Dental waxes have the greatest co-efficient of thermal expansion than any other restorative materials in dentistry. Eg : CTE of type 1 wax is[ between 22C and 37.5C ] is 32310-6

FLOW (of wax) Is the slippage of wax molecules over each other. Measure of flow is the measure of the degree of plastic deformation of material at a given temperature

MECHANICAL PROPERTIES Compressive strength, proportional limit, elastic modulus of waxes are low. These properties strongly depends on the temperature As the temp decreases mechanical properties improve

Dental wax component

PATTERN WAXWaxCompositionFunctionsTypesColour Form

Inlay wax

Paraffin wax Carnauba wax Ceresin wax Bees wax Gum dammar It is used to make patterns for metallic restorations. Patterns for inlays, crowns and bridges is first made in wax and then converted into metal or ceramic by casting. (Classification(ADA Sp. No. 4) Type I: Medium wax employed in direct technique. Type II: Soft wax used for indirect technique for inlays and crowns.

Green Stick

Casting wax

Paraffin wax Gum dammar Carnauba wax Ceresin or candelilla wax Bees wax Colouring agent Used to produce the metallic component of partial denture on the cast.

Class I : 28 gauge, ,Flow of about 10 % at 35C Easily adaptable at 40 to 45C pink

Class II :30 gauge, ,Minimum flow of 60 % at 38C ,adapts well to the surface ,not brittle on cooling green

Class III: ready made shapes, Will burnout at 500C leaving no carbon residue ,Supplied As Sheets 0.40 and 0.32 mm thickness blue

Base Plate Wax/ Modelling Wax ***

Beeswax Paraffin Coloring matter Bite registration Use for base plate, wax spacer, bite rim and tray expansion. Used mainly in preparing wax patterns forprosthesis.__ Sheets of pink or red color.

Wax rim (bite rim)

The softening temp. is above the mouth temp. It is tough & resist fracture during removal from the cast. It used for : Restoring the occlusal relationship. Arrangement of teeth. Check the denture inside the patient mouth. __ Pinkish, Red Block and sheet

Shellac denture base/ shellac base plate***

shellac stearin acid talcum Colorant and excipients. Wax like resin stable at mouth temp. It has high softening temperature than other waxes. It is used as a temporary denture base. __ Pinkish-orange Sheets (cakes)

PROCESSING WAXWaxCompositionFunctionTypesColour, form and charactheristics

Sticky wax***

Yellow bees wax Resin Gum dammar It is used to align fractured parts of acrylic dentures. It is used to align fixed partial denture units before soldering. To stabilize broken denture until it is seal. Holding upper and lower cast together.

__ Yellow Stick

It is sticky when melted, with a max 5 %flow at 30 C and 90 % at 43 C . It adheres closely to the surfaces when applied to it. If movement occurs the wax tends to fracture than distort. At room temperature the wax is brittle and breaks easily

Utility Wax

Blend of Hydrocarbon Waxes Colorant & Excipients It can be used to alter the stock tray extensions.

__ Orange or dark red in color. sticks and sheets. In orthodontics, periphery wax is white in color Flow at 37.5C- min. 65 % and max. 80% . Pliable and tacky at 21-24C

Boxing & beading waxes:

Use: Beading wax is adapted around the impression borders to create the land area of the cast Boxing wax is used to build up vertical walls around the impression in orderto pour the gypsum product to make a cast base. (Border moulding)__ Supplied as : Boxing wax as sheets. (Soft and sticky) (Use after make final impression) Beading wax as strips. (2mm after short sulcus) (Give shape of cast) (Give final impression at medial and lateral surface)

Block out wax

Used for filling the undercut area on the cast during processing of the Cr-Co frame work.

__ Red

IMPRESSION WAXESWaxComposition FunctionTypesColour and Form

Corrective wax Wax in combination with resins of low melting point can be used in corrective impression technique in partial and complete denture prosthesis. Thepeculiarity of impression wax is that they flow at mouth temperature. Used to restore the selected region in the edentulous patients to reproduce the details of mucous membrane. Its main disatvantage is that it is distorted during remove from the undercut areas.

__ Red

Bite registration wax :

It is used to record the relationship of the upper & lower teeth in dentulous patients.

__ sheets or cakes

Impression Compound/ Greenstick***

Resins (e.g. wax) Filler (e.g. talc or soapstone) 3. Lubricants (stearic acid or stearin) For individual tooth impression To check undercuts in inlay preparation Peripheral tracing or border moulding

Type 1- Impression compoundSticks/ High fusing

For making preliminary impression in edentulous mouth To make a special tray To prepare a tray for making an impressionType 2- Tray compoundCakes (sheets)/ Low fusing