PREPARATIONS PREPARATIONS FOR PARTIAL FOR PARTIAL

VENEER CROWNSVENEER CROWNS

PREPARATIONS PREPARATIONS FOR PARTIAL FOR PARTIAL

VENEER CROWNSVENEER CROWNS

MAXILLARY POSTERIOR MAXILLARY POSTERIOR THREE QUARTER CROWNSTHREE QUARTER CROWNSMAXILLARY POSTERIOR MAXILLARY POSTERIOR THREE QUARTER CROWNSTHREE QUARTER CROWNS

THE STANDARD THREE QUARTER THE STANDARD THREE QUARTER CROWN IS A PARTIAL VENEER CROWN IN CROWN IS A PARTIAL VENEER CROWN IN WHICH THE BUCCAL SURFACE IS LEFT WHICH THE BUCCAL SURFACE IS LEFT UNCOVERED. IT IS THE MOST COMMONLY UNCOVERED. IT IS THE MOST COMMONLY USED PARTIAL VENEER CROWN.USED PARTIAL VENEER CROWN.

OCCLUSAL REDUCTION IS THE FIRST STEP IN OCCLUSAL REDUCTION IS THE FIRST STEP IN PREPARING A TOOTH FOR A THREE PREPARING A TOOTH FOR A THREE QUARTER CROWN. DEPTH ORIENTATION QUARTER CROWN. DEPTH ORIENTATION GROOVES ARE CUT ON THE ANATOMIC GROOVES ARE CUT ON THE ANATOMIC RIDGES AND GROOVES OF THE OCCLUSAL RIDGES AND GROOVES OF THE OCCLUSAL SURFACE WITH A ROUND END TAPERED SURFACE WITH A ROUND END TAPERED DIAMOND. CLEARANCE SHOULD BE 1.5 mm DIAMOND. CLEARANCE SHOULD BE 1.5 mm ON THE FUNCTIONAL CUSP ( lingual on ON THE FUNCTIONAL CUSP ( lingual on maxillary teeth) AND 1 mm ON THE NON maxillary teeth) AND 1 mm ON THE NON FUNCTIONAL CUSP (facial)FUNCTIONAL CUSP (facial)

NEXT THE FUNCTIONAL CUSP BEVEL IS NEXT THE FUNCTIONAL CUSP BEVEL IS MADE. HOLDING THE ROUND-END TAPERED MADE. HOLDING THE ROUND-END TAPERED DIAMOND AT A 45 degree ANGLE TO THE DIAMOND AT A 45 degree ANGLE TO THE LONG AXIS OF THE PREPARATION, 3-5 LONG AXIS OF THE PREPARATION, 3-5 DEPTH-ORIENTATION GROOVES ARE DEPTH-ORIENTATION GROOVES ARE PLACED ON THE LINGUAL OR OUTER PLACED ON THE LINGUAL OR OUTER INCLINE OF THE LINGUAL CUSP. THE INCLINE OF THE LINGUAL CUSP. THE GROOVES ARE 1.5 mm DEEP AT THE CUSP GROOVES ARE 1.5 mm DEEP AT THE CUSP TIP AND FADE OUT AT THEIR APICAL END.TIP AND FADE OUT AT THEIR APICAL END.

AXIAL REDUCTION IS BEGUN BY REDUCING AXIAL REDUCTION IS BEGUN BY REDUCING THE LINGUAL SURFACE WITH A TORPEDO THE LINGUAL SURFACE WITH A TORPEDO DIAMOND, TAKING CARE NOT TO DIAMOND, TAKING CARE NOT TO OVERINCLINE THE LINGUAL WALL. OVERINCLINE THE LINGUAL WALL.

THE CUT IS EXTENDED INTERPROXIMALLYTHE CUT IS EXTENDED INTERPROXIMALLY AS THE AXIAL REDUCTION IS DONE, A AS THE AXIAL REDUCTION IS DONE, A

CHAMFER FINISH LINE IS FORMED.CHAMFER FINISH LINE IS FORMED.

PROXIMAL ACCESS IS GAINED BY USING A SHORT PROXIMAL ACCESS IS GAINED BY USING A SHORT NEEDLE DIAMOND IN AN UP AND DOWN SAWING NEEDLE DIAMOND IN AN UP AND DOWN SAWING MOTION. THIS IS CONTINUED FACIALLY UNTIL MOTION. THIS IS CONTINUED FACIALLY UNTIL CONTACT WITH THE ADJACENT TOOTH IS BROKEN.CONTACT WITH THE ADJACENT TOOTH IS BROKEN.

THE GIGIVO FACIAL ANGLE SHOULD NOT BE THE GIGIVO FACIAL ANGLE SHOULD NOT BE UNDER EXTENDED; IT IS THE MOST LIKELY AREA UNDER EXTENDED; IT IS THE MOST LIKELY AREA OF A THREE QUARTER CROWN TO FAIL.OF A THREE QUARTER CROWN TO FAIL.

THE AXIAL WALL AND THE AXIAL WALL AND CHAMFER ARE CHAMFER ARE FINISHED WITH FINISHED WITH TORPEDO BUR OF THE TORPEDO BUR OF THE SAME SIZE AND SAME SIZE AND CONFIGURATION.CONFIGURATION.

PROXIMAL GROOVES PROXIMAL GROOVES ARE APPROXIMATELY ARE APPROXIMATELY THE SIZE OF A NO. THE SIZE OF A NO. 171L BUR. GROOVE 171L BUR. GROOVE SHOULD BE PLACED SHOULD BE PLACED AS FAR FACIALLY AS AS FAR FACIALLY AS POSSIBLE WITHOUT POSSIBLE WITHOUT UNDERMINING THE UNDERMINING THE FACIAL SURFACE, FACIAL SURFACE, PARALLELING THE PARALLELING THE LONG AXIS OF A LONG AXIS OF A POSTERIOR TOOTHPOSTERIOR TOOTH

A FLARE IS A FLAT PLANE THAT REMOVES A FLARE IS A FLAT PLANE THAT REMOVES EQUAL AMOUNTS OF THE FACIAL WALL OF EQUAL AMOUNTS OF THE FACIAL WALL OF THE GROOVE AND THE OUTER SURFACE THE GROOVE AND THE OUTER SURFACE OF THE TOOTH. IT IS CUT FROM THE OF THE TOOTH. IT IS CUT FROM THE GROOVE OUTWARD WITH THE TIP OF A GROOVE OUTWARD WITH THE TIP OF A FLAME DIAMOND TO PREVENT OVER FLAME DIAMOND TO PREVENT OVER EXTENSION. THE FLARE SHOULD BE EXTENSION. THE FLARE SHOULD BE SMOOTHENED WITH A CARBIDE BUR SMOOTHENED WITH A CARBIDE BUR MATCHING THE CONFIGURATION OF THE MATCHING THE CONFIGURATION OF THE FLAME DIAMOND.FLAME DIAMOND.

THE OCCLUSAL THE OCCLUSAL OFFSET, A 1 mm WIDE OFFSET, A 1 mm WIDE LEDGE ON THE LEDGE ON THE LINGUAL INCLINE OF LINGUAL INCLINE OF THE FACIAL CUSP. IT IS THE FACIAL CUSP. IT IS MADE WITH A NO.171L MADE WITH A NO.171L BUR.BUR.

A 0.5 mm BEVEL A 0.5 mm BEVEL ALONG THE BUCCO-ALONG THE BUCCO-OCCLUSAL FINISH OCCLUSAL FINISH LINE, PERPENDICULAR LINE, PERPENDICULAR TO THE PATH OF TO THE PATH OF INSERTION INSERTION

POSTERIOR PARTIAL VENEER POSTERIOR PARTIAL VENEER VARIATIONSVARIATIONS

A THREE-QUARTER A THREE-QUARTER CROWN PREPARATION CROWN PREPARATION WITH PROXIMAL WITH PROXIMAL BOXES IS MORE BOXES IS MORE RETENTIVE THAN A RETENTIVE THAN A STANDARD STANDARD PREPARATION WITH PREPARATION WITH GROOVES. BUT BOXES GROOVES. BUT BOXES ARE VERY ARE VERY DESTRUCTIVE. THEY DESTRUCTIVE. THEY CAN BE JUSTIFIED CAN BE JUSTIFIED ONLY IF THERE HAS ONLY IF THERE HAS BEEN PREVIOUS BEEN PREVIOUS CARIES OR CARIES OR RESTORATIONS.RESTORATIONS.

A THREE-QUARTER CROWN A THREE-QUARTER CROWN PREPARATION ON A PREPARATION ON A MANDIBULAR MOLAR OR MANDIBULAR MOLAR OR PREMOLAR HAS MANY PREMOLAR HAS MANY FEATURES FOUND IN THE FEATURES FOUND IN THE PREPARATION OF THE PREPARATION OF THE MAXILLARY TOOTH. THE MAXILLARY TOOTH. THE BIGGEST DIFFERENCE IS BIGGEST DIFFERENCE IS THE LOCATION OF THE THE LOCATION OF THE OCCLUSAL FINISH LINE ON OCCLUSAL FINISH LINE ON THE FACIAL SURFACE, THE FACIAL SURFACE, GINGIVAL TO OCCLUSAL GINGIVAL TO OCCLUSAL CONTACTS. THERE IS NO CONTACTS. THERE IS NO NEED FOR AN OFFSET ON NEED FOR AN OFFSET ON THE LINGUAL INCLINES OF THE LINGUAL INCLINES OF THE BUCCAL CUSPS.THE BUCCAL CUSPS.

THE SEVEN-EIGHTS THE SEVEN-EIGHTS CROWN IN A THREE-CROWN IN A THREE-QUARTER CROWN WHOSE QUARTER CROWN WHOSE VERTICAL DISTO-VERTICAL DISTO-OCCLUSAL MARGIN IS OCCLUSAL MARGIN IS POSITIONED SLIGHLTLY POSITIONED SLIGHLTLY MESIAL TO THE MIDDLE OF MESIAL TO THE MIDDLE OF THE BUCCAL SURFACE.THE BUCCAL SURFACE. ESTHETICS ARE GOOD.ESTHETICS ARE GOOD. RESISTANCE IS BETTER RESISTANCE IS BETTER

THAN THAT OF THE THREE THAN THAT OF THE THREE QUARTER CROWN.QUARTER CROWN.

EASY TO DO.EASY TO DO. CLEANING BY THE PATIENT CLEANING BY THE PATIENT

ARE ALSO FACILITATED.ARE ALSO FACILITATED.

THE REVERSE THREE-THE REVERSE THREE-QUARTER CROWN IS QUARTER CROWN IS USED ON MANDIBULAR USED ON MANDIBULAR MOLARS TO MOLARS TO PRESERVE AN INTACT PRESERVE AN INTACT LINGUAL SURFACE.LINGUAL SURFACE.

IT IS USEFUL ON FIXED IT IS USEFUL ON FIXED PARTIAL DENTURE PARTIAL DENTURE ABUTMENTS WITH ABUTMENTS WITH SEVERE LINGUAL SEVERE LINGUAL INCLINATIONS.INCLINATIONS.

THE PROXIMAL THE PROXIMAL HALF CROWN IS A HALF CROWN IS A THREE-QUARTER THREE-QUARTER CROWN THAT IS CROWN THAT IS ROTATED 90 ROTATED 90 degrees WITH THE degrees WITH THE DISTAL RATHER DISTAL RATHER THAN THE BUCCAL THAN THE BUCCAL SURFACE LEFT SURFACE LEFT INTACT.INTACT.

ANTERIOR THREE QUARTER ANTERIOR THREE QUARTER CROWNSCROWNS

CREATE A CONCAVE CREATE A CONCAVE LINGUAL REDUCTION LINGUAL REDUCTION INCISAL TO THE INCISAL TO THE CINGULUM. IT IS CINGULUM. IT IS NECESSARY TO CREATE NECESSARY TO CREATE 0.7 mm OR MORE 0.7 mm OR MORE CLEARANCE WITH CLEARANCE WITH OPPOSING TEETH.OPPOSING TEETH.

TO ENSURE ADEQUATE TO ENSURE ADEQUATE REDUCTION DEPTH REDUCTION DEPTH ORIENTATION CUTS ARE ORIENTATION CUTS ARE MADE ON THE LINGUAL MADE ON THE LINGUAL SURFACE.SURFACE.

INCISAL REDUCTION IS INCISAL REDUCTION IS DONE WITH THE DONE WITH THE SMALL WHEEL SMALL WHEEL DIAMOND. IT DIAMOND. IT PARALLELS THE PARALLELS THE INCLINATION OF THE INCLINATION OF THE UNCUT INCISAL EDGE UNCUT INCISAL EDGE AND BEARLY BREAKS AND BEARLY BREAKS THROUGH THE THROUGH THE LABIOINCISAL LINE LABIOINCISAL LINE ANGLE.ANGLE.

THE DIAMOND IS KEPT THE DIAMOND IS KEPT PARALLEL WITH THE PARALLEL WITH THE INCISAL TWO-THIRDS OF INCISAL TWO-THIRDS OF THE LABIAL SURFACE TO THE LABIAL SURFACE TO INITIATE THE PATH OF INITIATE THE PATH OF INSERTION OF THE INSERTION OF THE PREPARATION.PREPARATION.

THE INSTRUMENTS COMES THE INSTRUMENTS COMES FROM THE LINGUAL, TO FROM THE LINGUAL, TO MINIMIZE DISPLAY OF MINIMIZE DISPLAY OF METAL LATER. AN UP AND METAL LATER. AN UP AND DOWN MOTION IS USED DOWN MOTION IS USED WITH CARE NOT TO NICK WITH CARE NOT TO NICK THE ADJACENT TOOTH OR THE ADJACENT TOOTH OR LEAN THE DIAMOND TOO LEAN THE DIAMOND TOO FAR INTO THE CENTRE OF FAR INTO THE CENTRE OF THE PREPARED TOOTH THE PREPARED TOOTH

THE AXIAL REDUCTION THE AXIAL REDUCTION IS COMPLETED AND IS COMPLETED AND THE FINISH LINE IS THE FINISH LINE IS ACCENTUATED WITH A ACCENTUATED WITH A TORPEDO DIAMOND.TORPEDO DIAMOND.

THE GROOVES ARE THE GROOVES ARE PLACED AS FAR PLACED AS FAR LABIALLY AS POSSIBLE LABIALLY AS POSSIBLE WITHOUT WITHOUT UNDERMINING THE UNDERMINING THE LABIAL ENAMEL PLATE.LABIAL ENAMEL PLATE.

ON THE FACIAL ON THE FACIAL ASPECT OF EACH ASPECT OF EACH GROOVE, A FLARE IS GROOVE, A FLARE IS STARTED AT THE STARTED AT THE GINGIVAL END WITH GINGIVAL END WITH THE THIN TIP OF A THE THIN TIP OF A FLAME DIAMOND. FLAME DIAMOND.

THE GROOVES ARE THE GROOVES ARE CONNECTED WITH AN CONNECTED WITH AN INCISAL OFFSET, INCISAL OFFSET, STAYING A UNIFORM STAYING A UNIFORM DISTANCE FROM THE DISTANCE FROM THE INCISAL EDGE. INCISAL EDGE.

A 0.5 mm WIDE A 0.5 mm WIDE BEVEL IS PLACED BEVEL IS PLACED ON THE ON THE LABIOINCISAL LABIOINCISAL FINISH LINE.FINISH LINE.