32 DENTAL WAXES

Luca Martinelli

Dental waxes

Publication nr. 32 - Revision -  06/04/2015

DENTAL WAXES

1 Waxes

Wax is the most used substance in dental laboratory to realize fixed and removable dental prothesis.

Dental waxes are mostly made by natural and synthetic waxes.

This substance is thermoplastic and it’s almost irreplaceable because its properties permit to be easily modelled and to return from liquid state to solid whithout the need of appropriate intervention apart from a simple cooling.

This means that wax permits to realize precise shapes that remain so after both hot and cool modelling.

Dental waxes must have special features compared to the common wax. Those features have to impart a low coefficient of thermal expansion and contraction; when using instrument to heat and shape, the dental waxes features have to guarantee a uniform heating, the possibility to be modelled by removal, the resistance even with low thicknesses and the maintenance of the given shape in time.

In order to preserve their properties, dental waxes have to handled and worked with some minimal expedients such as homogeneous warming of the mass, warmed up for a not extremely prolonged time (in order not to loose some elements by evaporation) and the run dry softening, not using water in order to avoid the absorpion of it, which would negatively influence on wax properties.

2 Wax categorization
Waxes are divided in:

·                     Natural waxes;

·                     Synthetic waxes.

To waxes, additives are added, some of which have the purpose to modify waxes characteristics, such as for example: colouring them with pigments, increasing the conditions of fusion interval with natural greases, increasing the hardness with artificial resins (or natural) or increasing the plasticity with oils.

Natular waxes family:

·                     Animal waxes;

·                     Vegetal waxes;

·                     Mineral waxes.

Synthetic waxes are instead produced by chemical synthesis or by modifying natural waxes.

2.1 Animal waxes

2.1.1 Beeswax

It is extracted by honeycombs from beehives. It’s the secondary component of dental waxes; it means that it represents in percentage their majour component. It is always in union with other products.

2.2 Vegetal waxes

2.2.1 Wax (resin) Carnauba

It is obtained by distilling some Brazil palms (Copernicia prunifera) which have a resinous exuded on their surface.

Used for the dental waxes for fusions realization, it is necessary for giving cohesion to the compound, for encreasing the elasticity of it and for maintaining constant tensing relation.

In particular it doesn’t leave combustion remains and so it doesn’t cause superficial alterations in fusions.

It gives higher hardness to waxes and encreases their fusion interval.

2.2.2 Candelilla wax

Obtained through desert herbs (Euphorbia Cerifera and Euforbia Antisyfilitica) mostly from  Mexico and Texas, usually mixed with paraffin to encrease hardness characteristics and fusion interval of dental waxes.

2.3 Mineral waxes

2.3.1 Paraffin

It’s a hydrocarbons mix, extracted by petrol and also by distilling vegetals which grow in petrol zones by exudation of the same petrol. It gives more hardness to dental waxes.

2.3.2 Ozokerite

It’s made by raw petrol residuals, then distilled. It’s a hydrocarbon mix.

2.3.3 Ceresin

It is obtained by refining ozokerite. It is used (together with paraffin) to encrease the waxes fusion interval.

2.3.4 Montana

Obtained by wood coal hot extraction (some authors indicate by bituminous coal of Saxon and Thuringia). Like ceresin, ti is used together with paraffin to encrease the waxes fusion interval.

2.4 Synthetic waxes

They are obtained by complex organic compound of different aggregation; they have distinctive controlled properties.

They are generally produced by chemical synthesis or through the chemical modification of natural waxes.

3 Additives

3.1 Colofonia

Commonly called Greek pitch because it was used to be found fossilized in Greece in huge quantity. It is obtained by distillation of pine resin or by the remains of turpentine distillation (oleoresin obtained by conifers incision).

It is usually used to compose adhesive waxes, also used like antioxidant of low temperature of fusion alloys.

3.2 Shellac

It is made with hemiptera insect secretions (in particular the female of cochineal), it’s a resinous substance.

3.3 Stearin

Obtained by the treatment of bovine and equine greases remains. It’s used for the composition of some winter waxes or to encrease the fusion interval.

It is extracted also through palm oil.  

3.4 Dammara (Kauri)

Resin extracted by exudation of plants (some species of Agathis). It is used to encrease the hardness and resistance of dental waxes.

4 Waxes on the market

On the market there are a lot of dental waxes, every one of them made for a specific use.

We can find waxes to model or realize bases, waxes for fusions, for inlays, waxes that appears like prepackaged section bar for frameworks, spine fusion, root post etc, adhesive waxes to join models, boxing waxes, winter or summer waxes and so on until arriving to special waxes.

4.1 Some examples of dental waxes compositions (an example of shape and colour that you can find on the market)

End use and wax composition of some producers:

·                     Occlusion wax – Compound of animlal and vegetal waxes together with a special aluminium powder (in sheets – silver colour);

·                     Modelling wax for crowns and bridges - Compound of natural and synthetic waxes or mixing of aromatic microcrystalline hydrocarbons (in box - colour blue; round – colour green, beige, opaque, gray very opaque);

·                     Modelling wax for pressable ceramic structures – Balanced mixture of waxes (in jar – colour ivory);

·                     Stackable precision modelling wax – balanced waxes mixture (in jar – colour blue or green);

·                     Wax to eliminate undercuts – Mixture of natural and synthetic waxes (in jar – colour pink);

·                     Little hoods immersion wax (metal-ceramic hoods) – Balanced mixture of waxes (flakes – colour green or blue);

·                     Wax for plaques – Mineral waxes, vegetal, animal and syntetics (in sheets – colour pink);

·                     Wax for bases - Paraffin (65%) and microcrystalls (35%) – (in sheets – colour pink);

·                     Modelling wax for mobile prothesis – beeswax, paraffin, carnauba (in sheets – colour pink);

·                     Occlusion rim wax – Mineral, vegetal, animal waxes (straight bars or horseshoe shape – colour yellow, red);

·                     Hard sticky wax – Beeswax, ceresin, dammara (in chopsticks – colour natural, red, yellow);

·                     Sticky wax “normal” – Mineral, vegetal, animal synthetic waxes (blocks – colour red);

·                     Wax for profiled (Bars, pins etc) – Mineral, vegetal, animal and synthetic waxes (wires, coils – colour green, blue).

Depending to the producer, to the different kind of waxes, and different techniques of modelling, waxes supplied with more variety of shape and colour can exist.

5. Special waxes (hints)

Just a hint to recollect that those waxes are not made with different components to the just seen ones. They are waxes simply composed with expecially studied percentages in order to give them particular characteristics.

Here we can find for examples the waxes for drilling. Very strong, they conserve their smooth surface even after the drilling; or the cervical waxes that have to be sliding and resistant to perfectly cover the border and to resist, despite the reduced thickness; the adhesive waxes to place nourice, fusion conduit or preformed elements and so on.

6. Fusion temperature

There are precise indications about fusion interval temperature of waxes used as raw material for dental waxes. For example, the fusion interval temperature of beeswax is 62/65°C; the one of carnauba wax is 83/91°C; the paraffin one is 40/70°C etc. De facto, however, the temperature interesting for the technician is the one indicated on the single items box, put on the market.

Into the wax that we can find on the market the fusion point change from wax to wax, from composition to composition, from producer to producer. The choice of a wax with defined characteristics is more dued to experience and practice of the technician, who prefers one or another depending on his habits, ability and type of work to make, instead of techincal-academic informations.

Let’s see the fusion point temperature of some waxes on the market:

·                     Occlusion rim wax mix (mixture of animal, vegetal wax together with special aluminium powder) – Fusion point 60/63°C;

·                     Bridges and crowns modeling wax (mixture of natural and synthetic waxes) – Fusion point 60/61°C;

·                     Wax for undercuts (mixture of natural and synthetice waxes) – Fusion point 80/85°C;

·                     Occlusion rim wax (mixture of mineral, vegetal, animal waxes) – Fusion point 59/62°C;

·                     Sticky hard wax (misture of beeswax, ceresin, dammara) – Fusion point 60/61°C;

·                     Sticky wax (mixture of mineral, vegetal, animal and synthetic waxes) - Fusion point 63°C;

·                     Modelling mobile wax (mixture of mineral, vegetal, animal, synthetic waxes) – Fusion point 59°C;

·                     Mobile prothesis wax (mixture of beeswax, paraffin, carnauba) – Fusion point 60/63°C;

·                     Mobile prothesis wax (paraffin 65% and microcrystals 35%) – Fusion point 57°C;

·                     Modelling wax for fixed elemets (mixture of aromatic microcrystal hydrocarbons) –Fusion point 65/75°C.

·                      Profiles in wax for sprues and bars (mixture of mineral, vegetal, animal and synthetic waxes) – Fusion point 63°C.

The list would be longer and the temperatures even different depending on the single characteristic conferred by the manufacturer to its own product.

7. Which wax to choose

A formula to choose the necessary kind of wax doesn’t exist. The experience of the dental technician and the indications of the single manufacturers, that for every product can supply information about the end use, temperature and suggestions on how to use, are the existing data.

Then those are the unique real two instruments to choose a wax that would be perfect for the technician’s needs, even if we cannot deny that, nowadays, the choice is necessarily influenced by the cost.

8. Some wax manufacturers

As for the main part of the products, even for waxes you can find many manufacturers. Here you can find a list, merely indicative and surely incomplete, of the manufacturers mostly known on the odontotechnic panorama.

BEGO

Dental Manufacturing Spa

Dentaurum J.P.

Herer

Hygenic

KEMDENT (Associated Dental Products)

Talladium incorporated

Vertex Dental

VIRAB Snc

Whip Mix

YETI

Zingardi Srl