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Cast metal Full Crown , Cast metal Complete veneer crown. Zhu ziyuan Staff Room of Prosthodontics. Contents. What is the full crown? How many types of the full crown are there? What’s the advantage of the metal cast crown? Which teeth need crowns? How are crowns done?.
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Cast metal Full Crown,Cast metal Complete veneer crown Zhu ziyuan Staff Room of Prosthodontics
Contents • What is the full crown? • How many types of the full crown are there? • What’s the advantage of the metal cast crown? • Which teeth need crowns? • How are crowns done?
What is the full crown • A dental restoration that completely reproduces the clinical crown of a natural tooth
Types of the crown • Metal full crown (金属全冠) • Non-metal full crown (非金属全冠)
Types of the crown • Combinatorial crown (金属—非金属混合全冠)
Metal crown( posterior tooth) • Cast (铸造) metal crown • Wrought (锤造)metal crown • Computer aided design and computer aided manufactory( CAD/CAM )metal crown
Non-metal crown( posterior and anterior tooth) • resin crown • ceramic crown • Cast glass ceramic crown • CAD/CAM ceramic crown • Porcelain crown
combinatorial crown (posterior and anterior tooth) • Porcelain fused to metal crown • Metal-resin crown
Definition of cast metal crown • Cast metal crown is a full crown restoration which is cast with dental alloy.
Advantages of cast metal crown • high Strength • tooth removed less • fitness • Long lasting • Fine protection
Indications of metal crown • Posterior tooth with large defect
Indications of metal crown • Malposition (错位), torsoclusion (扭转)or malformation of posterior tooth(形态不良) • Weak posterior abutment (基牙) of removable partial denture
Contraindications of metal crown • Incontrollable caries • People allergic to the metal • Tooth with esthetical requirement
Contraindications of metal crown • Residual root
Design of metal crown • Material selection
Design of metal crown • The position of gingival margin of the crown • To reduce the occlusal force
Tooth preparation • Occlusal reduction: • Provide the adequate room for the crown
Tooth preparation • Occlusal surface: • Amount of tooth reduction:1.0mm
Essentials of Occlusal preparation • Reduce the inclination of cusp
Essentials of Occlusal preparation • Prepare ladder on large filling material
Buccal and lingual reduction: • Provide the adequate room for the crown • Amount of tooth removing:1.0mm
Essentials of buccal and lingual preparation • The functional cusp bevel preparation
Proximal reduction: • Provide the adequate room for the crown • Amount of tooth removing:1.0mm
Essentials of axical preparation • Axial convergent angle 2°~5°
The axial surface angel preparation • To keep the contour of the crown
Cervical preparation • Chamfer or bevel • Width of shoulder • Non-noble metal:0.5~0.8mm • Noble metal:0.35~0.5mm
Position of gingival margin • At the gingiva • 1.0mm above gingiva • 0.5~1.0mm under gingiva
1.0mm 1.0 0.5 to 0.8 • Finish
Impression of metal crown • An imprint of the teeth and surrounding tissues, formed with a plastic material to provide a mold for use in making restorations
Impression steps • Impression of opposite teeth • Impression of abutment • Bite Registration
Gingival retraction • Retraction cord
Impression method • Two step method • One step method
Try in of metal crown • Check the gingival margin and tissular surface of the crown • Try in on the die
Try in of metal crown • Placement onto the abutment • Occlusal adjustment
Essentials • Pulp protection • Gingiva protection • Dental tissue protection
Essentials • Correct tool selection • Application of temporary crown • Occlusal adjustment
Essentials • Indications and contraindications • To improve the retention