WAX PATTERN FABRICATION FOR FPD INTRODUCTION USUALLY WAX

WAX PATTERN FABRICATION FOR FPD

INTRODUCTION USUALLY WAX PATTERN FABRICATION DENOTES THE WAX PATTERN FABRICATED TO CAST METAL OR CASTABLE GLASS CERAMICS (DICOR). WAX PATTERN FABRICATION INVOLVES THREE MAJOR STEPS NAMELY FABRICATION OF THE RETAINER, THE PONTIC AND CONNECTOR

FABRICATION OF THE RETAINER WAX PATTERN n THE METHOD OF FABRICATION OF THE RETAINER COMPONENT WILL VARY ACCORDING TO THE MATERIAL USED AND THE DESIGN OF THE RESTORATION

1. n n DIRECT TECHNIQUE WAX PATTERN IS FABRICATED DIRECTLY OVER THE PREPARED TOOTH IN THE ORAL CAVITY DONE WITH TYPE-I WAX, HENCE NOT USED FOR FIXED PARTIAL DENTURE PATTERN

2. INDIRECT TECHNIQUE n n PATTERN IS FABRICATED OVER THE PREPAIRED TOOTH IN THE DIE OR CAST MADE USING TYPE-II WAX ADVANTAGES: n n n DONE IN THE LAB THEREBY REDUCING THE CHAIRSIDE TIME DONE BY TECHNICIAN THEREBY REDUCING WORK LOAD OF DENTIST ALLOWS BETTER VISUALISATION OF THE MARGINS OF THE RESTORATION ESPECIALLY FROM THE GINGIVAL ASPECT

PROCEDURE n FABRICATED BY PREPARING A WAX COPING FOLLOWED BY ADDING LAYERS OF WAX TO BUILD UP AXIAL AND OCCLUSAL CONTOUR

COPING PREPARATION PROCEDURE n SURFACE CONTOURING AND MARGINAL FINISH ARE NECESSARY FOR ALL METAL OR DICOR CERAMIC RETAINER n IN METAL CERAMIC RETAINER COPING IS ALONE PREPARED AND CASTED USING METAL CERAMIC ALLOY n THE COTOURS AND MARGINS ARE DIERECTLY PREPARED USING CERAMIC AND FIRED

COPING PREPARATION n n DONE USING WAX OR HEATED SHEET OF RESIN WAX COATED ON THE TOOTH USING A WAX SPATULA OR BY DIPPING THE DIE INTO THE HOT WAX

n n WHILE ADDING NEW LAYERS OF WAX THE PREVIOUS LAYER SHOULD BE MELTED TO AVOID FORMATION OF VOIDS COPING SHOULD BE WAXED IN EXCESS MESIALLO DISTALLY TO PRESERVE PROXIMAL CONTACT

PREPARING THE AXIAL CONTOURS n n n ESTABLISHING THE PROXIMAL CONTACT USUALY THE PROXIMAL CONTACT OCCUR AT HE OCCLUSAL THIRD WHEN VIEWED FROM SIDE PROXIMAL CONTACT SHOULD BE FACIALLY LOCATED WHEN VIEWED OCCLUSALLY

n CONTACT AREA SHOULD BE OPTIMUM

n n AXIAL SURFACE BELOW THE CONTACT SHOULD NEVER BE CONVEX LINGUAL PROMINENCE IS GREATER FOR MANDIBULAR POSTERIORS THAN MAXILLARY POSTERIORS

n HEIGHT OF CONTOUR ON THE LINGUAL SURFACE MAXILLARY POSTERIORS OCCUR IN CERVICAL THIRD AND THE SAME IN MANDIBULAR POSTERIORS OCCUR IN MIDDLE THIRD

PREPARING THE OCCLUSAL CONTOUR OR DEVELOPING OCCLUSAL MORPHOLOGY IT SHOULD BE IN HARMONY WITH ADJUSENT OR OPPOSITE TEETH n P. K. THOMAS CARVERS ARE USED TO CARVE THE OCLUSAL SURFACE PROCEDURE: n TAIL END OF PKT CARVER SHOULD BE USED TO BUILT CONES OF WAX OVER THE AREAS WHERE THE CUSPS ARE TO BE FORMED n

n n MARGINAL RIDGES AND CUSP RIDGES ARE BUILT USING SAME INSTRUMENT PARTIALY WAXED OCCLUSAL SURFACE IS OCCLUDED AGAINST THE OPPOSING CAST

n n n INTERNAL INCLINES OF THE CUSP ARE CONTORED RIDGES SHOULD BE CONVEX OCCLUSAL MORPHOLOGY SHOULD BE MODIFIED ACCORDING TO SURROUNDING TEETH

FINISHING THE MARGINS OF THE PATTERN n n MARGINS ARE FINISHED TO A FINE EDGE USING BURNISHER A COTTON PELLET SOAKED IN DIE LUBRICANT IS USED TO FINISH THE OCCLUSAL GROOVES

n n THE AXIAL SURFACE IS FINISHED WITH A COTTON ROLL DIPPED IN A DIE LUBRICANT REMOVE THE LUBRICANT AFTER FINISHING

PONTIC FABRICATION OF WAX PATTERN FOR METAL CERAMIC AND RESIN VENEERED PONTICS : PROCEDURE : o AXIAL SURFACES ARE CONTOURED AS DESCRIBED FOR A RETAINER o INLAY WAX IS SOFTENED AND FUSED TOOTH RETAINER IN THE FORM OF A CYLINDER

n n WAX CONE SHOULD BE PLACED ON THE FLAT OCCLUSAL SURFACE INORDER TO CONTOUR THE OCCLUSAL SURFACE THE RETAINER PATTERNS ARE FINISHED AND THE PROXIMAL AND THE GINGIVAL SURFACE OF THE PONTIC ARE CONTOURED ACCORDING TO THE NEIGHBOURING TEETH

n GINGIVAL SURFACE IS CONTOURED ACCORDING TO DESIGN OF THE PONTIC