Odontological use Waxes

CLINICAL AND LABORATORY PROCEDURES

  • Dental preparation and temporalization.
  • Taking of definitive impression.
  • Elaboration of work models cast type IV-V plaster. mounting.
  • Preparation of the wax pattern.
  • Coating of the wax pattern.
  • Casting.
  • Tests of only metal structures, only ceramics, metal-ceramics. Cementing of the restoration, follow-up.

ODONTOLOGICAL USE WAXES

COMPOSITION:

Natural and synthetic waxes.

  • Gum.
  • Greases.
  • Fatty acids.
  • Oils.
  • Natural and synthetic resins.
  • Pigments of various types.

 

CLASSIFICATION OF WAXES

According to its origin:

  • Natural and synthetic.

According to its chemical composition:

  • Hydrocarbons and esters.

According to its use:

  • Casting waxes.
  • Prefabricated shapes.
  • Base waxes.
  • Processing waxes.
  • Waxes for prints and records.

CLASSIFICATION OF WAXES BY THEIR ORIGIN

NATURALS : Complex combinations of relatively high molecular weight organic compounds.

  1. MINERAL ORIGIN:
    • Main hydrocarbon component of 17 to 44 carbon atoms.
    • Odd or even chains.
    • Paraffin, Microcrystalline, Cerezina, Montana, Ozoquerita, Barnsdahl.
  2. VEGETAL ORIGIN:
    • They have hydrocarbons which are saturated alkanes with 19 to 31 carbon atoms always in odd numbers.
    • Carnauba, candelilla, Japanese wax, uricuri, cocoa butter.
  3. ANIMAL ORIGIN:
    • Beeswax, spermaceti
    • Beeswax esters plus saturated and unsaturated hydrocarbons and organic acids of high molecular weight.
    • Modifies the properties of paraffin.
    • Main component of sticky wax.
    • Vegetable and animal waxes contain a considerable amount of esters, also acids, alcohols, hydrocarbons and resins.

MELTING TEMPERATURES

 PARAFFIN  40 – 70 ºC
 MICROCRYSTALLINE  60 – 91 ºC
 MONTANA  72 – 92 ºC
 BARNSDAHL  70 – 74 ºC
 OZOQUERITA  54 ºC
 CARNAUBA  84 – 91 ºC
 URICURI  79 – 84 ºC
 CANDELILLA  68 – 74 ºC
 BEE WAX  63 – 70 ºC

 

USE OF NATURAL WAXES

  • INCREASE INTERVAL OF MELTING TEMPERATURE
    • Montana, ceresin, carnauba, uricuri, barnsdahl, candelilla.
  • DUREZA
    • Carnauba, Montana, Uricuri, Barnsdahl.
  • ADHESIVIDAD
    • Japan wax, cocoa butter are fats.
    • Japan wax + paraffin = Improves adhesiveness.
    • Cocoa Butter = Hydrate soft tissues.

 

SYNTHETIC WAXES

  • Complex organic compounds of diverse chemical composition.
  • They are very refined.
  • They do not contain the frequent contamination of natural waxes.
  • They melt between 100ºC-105ºC
  • Polyethylene waxes, polyoxyethylene glycol
  • Hydrogenated, halogenated hydrocarbon waxes.
  • They work as plasticizers.

OTHER WAX COMPOUNDS

  • GUM: Viscous and amorphous exudates of plants and animals.
    • They contain Carbohydrates.
    • When mixed with water they form sticky and viscous liquids.
    • Tragacanth and arabic gum.
  • RESINS: They are complex and amorphous mixtures of organic substances.
    • Danmar, colofonia, Kaurí.
  • GREASES: Tasteless, odorless and colorless in pure form.
    • Composed by Glycerides.
    • Glycerides of stearic acid or tristearate are in sebum..
    • Oleic, palmitic and butyric acids in butter.
    • Silicone oils to facilitate the polishing of waxes.

 

CLASSIFICATION OF WAXES BY THEIR USE IN DENTISTRY

CASTING WAX

  • INCRUSTATIONS:
    • TYPE I: Preparation of patterns directly in the mouth.
    • TYPE II: Preparation of patterns with indirect technique.
  • CALIBRATED WAX. PPR
  • PREFABRICATED SHAPES. PPR

BASE WAX

  • Type I : Soft.
  • Type II : Regular.
  • Type III : Hard (hot climates)

USES:

  • Total prothesis, patterns for orthodontic appliances.
  • Partial prothesis, check the articular relationships in the mouth.

PROCESSING WAX

  • Formwork: Baseboards
  • Sticky: Making Rigid Keys
  • Utility: Add on bucket flanks.

WAXES FOR IMPRESSIONS AND RECORDS

 

PROPERTIES OF WAX

  • MELTING INTERVAL. By having molecules of different molecular weight and different types of molecules.
  • THERMAL EXPANSION COEFFICIENT :
    • They expand when temperature raises.
    • They contract when temperature contraen al decreases.
    • The temperature changes experienced by wax patterns after establishing critical dimensional relationships may represent an important factor that generates inaccuracies in the finished restoration.
    • Process the waxes in the shortest possible time and with a minimum of ambient temperature changes.
  • RIGIDITY: Allows fine grinding work without peeling.
  • DRAINAGE-THERMOFLUENCE:
    • Plastic deformation on certain temperatures.
    • Copy of details.
  • DUCTILITY:
    • It increases as the temperature of the wax increases.
    • The waxes with lower melting temperature are more ductile. The same are those with wider melting intervals.

 

MECHANICAL PROPERTIES OF WAX

  • PROPORTIONAL LIMIT.
  • ELASTIC MODULE .
  • RESISTANCE TO COMPRESSION.
  • LOW

 

PROPERTIES OF WAX

  • CONCENTRATION OF TENSIONS:
    • The manipulation, softening and plastification, molding, compression, carving induce tensions that are stored affecting the molecular structure.

 

CASTING WAX

  1. When softening it must acquire uniform plasticity that allows molding.
  2. When hardening it should be allowed to be carved with metallic instruments, to give shape and to be able to thin it in the edges or margins without fracture.
  3. It has contrasting color.
  4. It has dimensional stability.
  5. When evaporating it does not leave residues of more than 0.10% at 500ºC

COMPOSITION:

  • Paraffin 40-60 %
  • Carnauba 25%
  • Ceresina.
  • Beeswax.

 

WAX PATTERN

  • It is the precursor of the cast restoration that will be placed in the prepared tooth.
  • The procedure is done with the wax loss technique.
  • A mold is made in a refractory lining, evaporating the wax in an electric furnace.
  • Application of separator in the dies.
  • An initial cap is made by introducing the die into a vessel with molten wax. Mantle or wax skin.
  • Waxing is recommended step by step.
  • The pattern should reproduce the proper anatomy of the patient’s teeth.

 

PROXIMAL SURFACES

  • They are flat or slightly concave from the contact to the cement-bonding joint.
  • They should not be too concave or under-contoured because the use of silk would be ineffective.
  • Over contouring causes difficulties in the maintenance of periodotal health.

 

CONTACT AREAS

  • Contacts that are too broad make it difficult to control the plaque, can lead to periodontal disease.
  • Small or punctual contacts can be unstable and cause travel.
  • Poor contacts can cause impaction of foods that cause discomfort to the patient.

 

POSTERIOR CONTACT AREAS

  • Occlusal third most, but between 1 and 2 upper molar in the middle third.
  • Contacts in direction V – L:
  • Mandibular teeth and maxillary molars generally in the middle of the occlusal surfaces.
  • Between premolars and upper molars towards the buccal surface.

 

AXIAL SURFACES

  • Similar to adjacent teeth.
  • Important: The location of the contour height is located in the gingival third of most teeth.
  • In the lower molars usually lingual the contour height is located in the middle third.
  • The contours generated by insufficient dental preparations make it difficult to remove plaque.

 

OCCLUSAL SURFACES

  • The cusps and crests should be shaped in such a way as to allow a homogenous contact with the opposing teeth while stabilizing the teeth and directing the forces longitudinally.
  • Point-shaped contacts.
  • Non-functional cusps should be vertically and horizontally overlapped to avoid cheek or tongue bites and to keep food on the occlusal table.

 

HEIGHT AND LOCATION OF CUSPIDES

  • The cones must be placed following the antero posterior curve (spee).
  • Mandibular cusps that lengthen distally.
  • Maxillary cusps are bounded distally.
  • Evaluate the eccentric movements in articulator.
  • In Wilson’s frontal plane, non-functional cusps shorter than functional cusps.
  • Eliminate interference.

 

TRIANGULAR CRESTES

  • VVertex of the triangle at the end of the cusp and base at the center of the occlusal surface.
  • Close articulator every time crests are added.

 

SECONDARY CRESTES

  • Two secondary ridges adjacent to each triangular crest.
  • Convex with grooves where the convexities are.

 

FINISHING THE MARGIN

  • The margins re-flow and end immediately before coating the wax pattern.

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