Dental Technology: Denture fabrication, acrylics, impression material, porosity, casting, dental waxes, gypsum, material science, infection control, PPE, Acrylic stages, denture errors, overheating acrylic, ortho, hawleys retainer

Stages in complete denture fabrication

Primary impression → Cast → Special tray → Final impression → Master cast → Record block → Jaw relation → Try-in → Processing → Polishing → Insertion

Heat-cured acrylic

Heat processed, strong, permanent dentures

Cold-cured acrylic

Room temp, weaker, repairs/temporary Dentures

1: Alginate use

Preliminary/study models

Silicone use

Crown & bridge (accurate)

ZOE use

Edentulous final impression

Causes of porosity

Rapid heating, air bubbles, moisture, wrong ratio

Prevention of porosity

Proper curing, good mixing, avoid moisture

Steps in lost-wax casting

Wax → Sprue → Invest → Burnout → Cast → Cool → Divest → Finish

Role of sprue former

Pathway for metal + escape for gases

Modelling wax

Denture setup

Boxing wax

Form mold for pouring

Utility wax

Border molding

Type II gypsum

Soft, study models

Type III gypsum

Strong, working casts

Plastic deformation

Permanent shape change beyond elastic limit

Annealing

Heat + slow cooling → soft

Tempering

Reheat → tough, less brittle

Cross-infection

Transfer of infection between patient & staff

Prevention

Sterilization, hand hygiene, PPE

PPE in dental lab

Gloves, mask, goggles, lab coat, covered shoes

Dough stage

Not sticky, not runny, moldable

Causes of raised bite

Improper packing, shrinkage, warpage, premature closure

Effects of overheating acrylic

Porosity, discoloration, dimensional change, incomplete polymerization

Removable appliance

Can be removed (e.g. Hawley’s)

Fixed appliance

Cemented (e.g. braces)

Hawley’s Retainer Parts

Labial bow, clasps, acrylic base

Space maintainer use

Prevent drifting, maintain space

Die trimming

Exposes margins, improves fit

Waste segregation

Infectious, non-infectious, sharps, chemical

Steps In temporary crown construction

Prep → Matrix → Mix → Seat → Trim → Cement

Dough stage meaning

Perfect consistency for packing

Weighting material location

Anterior region of lingual flange (lower denture)