Full Metal Crown PDF

1 Dr/ Enas Fathelbab  Definition. Types. Advantages. Disadvantages Indications. Contraindications. Preparation steps. 3 Dr/ Enas Fathelbab  Definition 4 Dr/ Enas Fathelbab  It is an extracoronal metallic full coverag...

1 Dr/ Enas Fathelbab  Definition. Types. Advantages. Disadvantages Indications. Contraindications. Preparation steps. 3 Dr/ Enas Fathelbab  Definition 4 Dr/ Enas Fathelbab  It is an extracoronal metallic full coverage fixed restoration that covers all the coronal surfaces of the prepared clinical crown and restores its function, anatomy and contour.  Types 6 Dr/ Enas Fathelbab  According to construction techniques 1- Cast ( lost wax technique) 2- Swaged (ready made) 3- CAD/CAM milling 7 Dr/ Enas Fathelbab  According to materials of construction 1- High noble alloys 2- Noble alloys 3-Base metal alloys 8 Dr/ Enas Fathelbab  Advantages 9 Dr/ Enas Fathelbab ▪ High strength. ▪ Great retention & resistance form. ▪ Good protection for teeth to be restored. ▪ Ideal restoration for teeth with developmental defects. ▪ Modifies occlusion (over eruption) ▪ Modifies tooth contour (open contact & retainer for PD). ▪ Has the best longevity of all fixed restorations.  Disadvantages 12 Dr/ Enas Fathelbab ▪ Bad esthetics. ▪ Extensive amount of tooth reduction.??? ▪ Pulp vitality can NOT be detected. ▪ Incipient caries can NOT be detected.  Indications 14 Dr/ Enas Fathelbab  For posterior teeth only. As a single crown As a bridge retainer As a Single Crown ▪ Patient with high caries index. ▪ Badly broken down tooth. ▪ Endodontically treated teeth. ▪ When maximum retention and resistance are needed ▪ For correction of malalignment teeth (change contour). ▪ Fractured teeth. ▪ To support a removable partial denture. ▪Badly broken down ▪ Endodontically treated teeth tooth  For correction of malaligment teeth (change contour). ▪Over erupted tooth ▪Tilted tooth  ▪Badly broken down/ fractured teeth ▪To support RPD 19 Dr/ Enas Fathelbab As a Bridge Retainer ? ▪ Long span bridge. ▪ Short OG height. ▪ High occ. Forces. WHY ?????  ▪Long span bridge. ▪ Short OG height  Contraindications 22 Dr/ Enas Fathelbab ▪ Anterior teeth. ▪ Another conservative preparation can made ( buccal surface intact ¾ crown ) ? ▪ Less max. retention & resistance is needed.( long clinical crown, short span bridge) ▪Anterior teeth ▪Buccal surface intact ▪Short Span Bridge ▪Long Clinical Crown Tooth Preparation Armamentarium  Preparation Criteria ▪ Finish Line: Chamfer , supra gingival ,0.5 mm. ▪ Axial reduction: Parallel to long axis of the tooth with 6 degree taper  Steps of Preparation 30 Dr/ Enas Fathelbab 1. Occlusal reduction & Functional cusp bevel. 2. Reduction of axial surfaces 3. Proximal reduction 4. Smoothing & Roundation 1. Occlusal reduction ▪ Tapered stone with rounded end , wheel or flame shape diamond stone. ▪ Cutting is following the occlusal anatomy. ▪ 1.5mm of clearance on the functional cusps. ▪ 1 mm on the non-functional cusps.  Depth Orientation Grooves ▪ Using fissure bur or rounded end tapered diamond to place 1mm depth ▪At central, mesial and distal fossa, marginal ridges, buccal and lingual developmental grooves ▪Tooth structure (islands) between the grooves is removed preserving the occlusal configuration ▪Amount of reduction should be uniform to allow adequate thickness of metal  HOW to check occlusal clearance???? ▪ Utility wax ▪Registration material ▪ Reduction gauge ▪Registration material ▪Reduction gauge: instrument used to check occlusal clearance , it has 2 spherical ends ( one 1 mm in diameter & other 1.5 mm ) Functional Cusp Bevel ▪ On the Palatal ▪ On the buccal inclination of Mx inclination of Md Palatal cusp buccal cusp What's happened if occlusal reduction is too thin or too wide?? 2. Axial Reduction ▪ Instrument: Taper with rounded end ▪ Finish Line: Chamfer Depth from 0.3-0.5 mm( 0.3 mm of base metal alloys & 0.5 mm of gold alloys ) Supragingival as possible Follow gingival contour. ▪Undercut ▪Over-convergence The recommended finish line should be not wider than half the tip diameter of the stone used to form it..WHY?? Depth Orientation Grooves ▪ Two planes: (Buccal of Md. & Palatal of Mx. Teeth) * Below the height of contour---- // to long axis of the tooth. * Above the height of contour ---- 45 degree with long axis of the tooth. ▪ One plane : ( Buccal of Mx.&lingual of Md. Teeth) What's happened if the axial reduction is too thin or too thick ??. 3. Proximal Reduction ▪ Instrument Fine taper diamond stone ( Needle stone ) Taper with rounded end ▪ Depth 0.3-0.5 mm cervically. 4. Smoothing & Roundation ▪ By the same size diamond stone with a finer grit ▪ Removal of any sharp line angles, point angles & undercut areas. ▪ Accentuation of the Chamfer Finish Line : ( smooth, rounded, continuous and follow gingival contour) ▪Rounding of all line angles ▪ Removal of cervical undercut at the line angle  End cutting diamond is used for …….??? Accentuation of the Chamfer Finish Line ▪Finished Preparation ▪Finished Restoration.  If Over tapering of opposing axial walls ► ► result in reduced retention. we can overcome this error ….HOW??? ? ? To overcome this error, we either; 1)Improve retention by adding grooves 2)Prepare a band of few mms of tooth structure with restricted 6 degree taper.  Auxiliary Retention & Resistance Form By : grooves, box or pinholes. Site: best place at the center of proximal but in some case placed buccal and lingual. ▪Over tapering of opposing axial walls ▪A band of few mms of tooth structure with restricted 6 degree taper. 89 Dr/ Enas Fathelbab