Waxes PDF - Dr.Thurra Abbas - 11/17/2024

waxes Dr.Thurra Abbas 11/17/2024  Used in many aspects of dentistry in the clinic and the laboratory. Although not used in the final dental restoration, waxes are often important in the fabrication and success of the final metal or ceramic restoration...

waxes Dr.Thurra Abbas 11/17/2024  Used in many aspects of dentistry in the clinic and the laboratory. Although not used in the final dental restoration, waxes are often important in the fabrication and success of the final metal or ceramic restoration 200 years ago BEESWAX USED FOR PATTERNS Dr.Thurra Abbas 11/17/2024  ‫التشميع‪:‬‬ ‫هو عبارة عن مرحلة مخبرية‪.‬يتم فيها الحصول على نماذج شمعية مطابقة لشكل وأبعاد التعويض‬ ‫النهائي فإما أن تكون‪:‬‬ ‫‪ 1-‬حشوة مصبوبة‪.‬‬ ‫‪ 2-‬تاج‪.‬‬ ‫‪ 3-‬أجهزة فيتاليوم تعويضية‪.‬‬ ‫‪ 4-‬أجهزة إكريلية تعويضية‬ ‫‪Dr.Thurra Abbas‬‬ ‫‪11/17/2024‬‬ Lost wax technique Dr.Thurra Abbas 11/17/2024 Dr.Thurra Abbas 11/17/2024  Mixture of various components Natural synthetic Minerals Plants Animals (Parafin,cresin) (Carnuba) (beeswax) Dr.Thurra Abbas 11/17/2024  60 Dr.Thurra Abbas 11/17/2024 Dr.Thurra Abbas 11/17/2024 Dr.Thurra Abbas 11/17/2024 Dr.Thurra Abbas 11/17/2024 Composition: organic molecules with high molecular weight Hydrocarbon: paraffin High molecular weight ester Dr.Thurra Abbas 11/17/2024  Pattern waxes  Casting waxes  Baseplate wax  Inlay wax  Resin waxes For lost wax technique Processing waxes  Boxing waxes  Utility waxes  Sticky wax Resins has recently been used as pattern or processing materials Dr.Thurra Abbas 11/17/2024  Properties of waxes are governed by ANSI-ADA spec.4 1-Melting range 2-Excess residue ‫مجال االنصهار‬ ‫الزوائد المتبقية‬ 3-Flow ‫االنسيابية‬ 4-Thermal expansion ‫التمدد الحروري‬ 5-Residual stress ‫الجهود المتبقية‬ Dr.Thurra Abbas 11/17/2024  INLAY WAX Physical Properties – Melting Range 100 90 LIQUID TEMPERATURE (C) 80 Melting Completion (Liquidus) 70 LIQUID + SOLID 60 50 40 30 Melting Onset (Solidus) 20 SOLID 25 50 75 100 Paraffin COMPOSITION (%) Carnuba Dr.Thurra Abbas 11/17/2024 Properties of waxes Melting range Excess residue Flow Thermal expansion Residual stress Because wax patterns used in the lost-wax technique are melted or burned to remove them from the casting mold, the wax must not leave a residue, which would affect the quality of the final restoration Dr.Thurra Abbas 11/17/2024 Properties of waxes Melting range Excess residue Flow Thermal expansion Residual stress Dr.Thurra Abbas 11/17/2024 Dr.Thurra Abbas 11/17/2024 Methods minimizing residual stress Heat the carver ‫احماء السكين‬ Add in small increments ‫اضافة احجام قليلة‬ ‫تغطيس بالماء بشكل متكرر‬ Store in isolation from temp. fluctuation (water) ‫ دقيقة‬30 ‫الكسي خالل‬ Invest within 30 min. ‫التأكد من التفاصيل والحواف‬ Refinish detail if in doubt (contact points,margins) Dr.Thurra Abbas 11/17/2024 Pattern waxes Inlay wax Casting wax Baseplate wax Resins Dr.Thurra Abbas 11/17/2024 Inlay wax 1- 7.5 cm long,6 mm wide 2- Five or six components(paraffin and cresin,carnaouba,beeswax) ,different hardness 3- In mouth or in lab temperatures Dr.Thurra Abbas 11/17/2024 Casting wax slight tackines Dr.Thurra Abbas 11/17/2024 Dr.Thurra Abbas 11/17/2024 Baseplate wax or record base wax 1- 7.5 cm wide,15cm long 0.13 mm thick 2- Three types depending on temperature Soft ,medium and hard. Dr.Thurra Abbas 11/17/2024 resins 1- Self cure =chemical cure (auto cure) 2- Light cure 3- composites Dr.Thurra Abbas 11/17/2024 Important properties of pattern waxes Low flow in working temperature to prevent distortion of the wax pattern Melting range higher than the environment : direct wax pattern higher ,lab patterns lower If the melting temperature is too high the wax will be difficult to work with Burn out without residue Dr.Thurra Abbas 11/17/2024 Processing waxes Dr.Thurra Abbas 11/17/2024  Boxing and utility waxes Periphery wax easly shaped Soft 40 cm strips ,4-5 cm wide Dr.Thurra Abbas 11/17/2024  Sticky wax When heated sticky ,when cold brittle Assembling metal and gypsum pieces Dr.Thurra Abbas 11/17/2024 Dr.Thurra Abbas 11/17/2024  Corrective impression wax Over original impression ,functional impression From paraffin and hydrocarbon wax Flow at mouth temperature 37 c 100% Susceptible to distortion upon removal Dr.Thurra Abbas 11/17/2024 Dr.Thurra Abbas 11/17/2024  Bite registration wax Susceptible to distortion during removal, flow 37 c 2.5-25% Widely replaced by Addition silicones and Polyethers Dr.Thurra Abbas 11/17/2024 Dr.Thurra Abbas 11/17/2024