Questions and Answers
What are the retentive features of Class IV cavity preparation?
What retention feature is found along the gingivoaxial line angle in Class IV restorations?
A retention groove
How are Class IV restorations cut?
With a bevel around the cavosurface margins
What is the purpose of beveled margins in Class IV restorations?
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Where are retention grooves located?
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What is the role of the gingivoaxial retention groove?
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At what point do facioaxial and linguoaxial line angles begin?
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Where is the retention pin placed?
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Where are the matrix and wedge placed during a Class IV prep?
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What are the primary functions of a matrix and a wedge?
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What type of matrix is used for Class IV restorations?
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What can be used as a matrix?
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Which strip provides more contouring for a Class IV composite?
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What is used to place the material into the cavity prep?
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When restoring Class IV cavity preps, which areas must be recreated?
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What surfaces must be contoured to prevent premature occlusal contact?
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What can damage an over contoured restoration?
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What can be used to finish a Class IV restoration?
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Large restorations require more sculpting with what instruments?
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What is a green stone used for?
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What is a white stone used for?
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What is special about finishing discs and strips?
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How should instruments be held when restoring the Class IV restoration?
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What should be done to examine a cavity prep?
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What is the application of calcium hydroxide meant to do?
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What should be done before the tooth is etched?
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What should be used when etching the prep?
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What is the proper bonding technique for the tooth?
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How should the tooth be measured before placing composite?
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What should be the approach when trimming the tooth?
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Study Notes
Class IV Composite Restorations Overview
- Class IV cavity preps require specific retentive features for effective restoration.
- Key retentive features include retention grooves, pins, beveled margins, and etched enamel margins.
Restoration Characteristics
- Class IV restorations include a retention groove along the gingivoaxial line angle, supporting the composite at the incisal edge with potential retention pins.
Preparation Techniques
- Utilization of a bevel around cavosurface margins enhances restoration bonding.
- Beveled margins are etched to improve composite retention without over contouring.
Retention Groove Details
- Retention grooves are positioned at gingivoaxial, facioaxial, and linguoaxial line angles.
- The gingivoaxial retention groove spans the line angle's entire length.
Placement and Function of Components
- Facioaxial and linguoaxial line angles start from gingival point angles, tapering off towards the DEJ at the incisal surface.
- Retention pins are positioned in the axial wall to provide additional support.
Matrix and Wedge Use
- Matrix and wedge are placed proximal and apical to the gingival margin to maintain material containment and prevent gingival overhang.
- A celluloid strip serves as the matrix for Class IV restorations, with a celluloid crown form offering more contouring potential.
Material Application
- Composite material is placed using a composite placing instrument or syringe, ensuring proper coverage of the prep area.
Restoration Areas
- Effective restoration recreates five crucial areas: mesial incisal edge, mesial marginal ridge, proximal surface (including contact area), facial surface, and lingual surface.
Contour Considerations
- Surfaces like the lingual, incisal, and marginal ridge must be properly contoured to avoid premature occlusal contacts.
- An over contoured restoration can be damaged by excessive biting and chewing forces.
Finishing Techniques
- Various instruments including finishing discs, stones, and rotary instruments are used to achieve the desired contour of large restorations.
- Green stones are coarse and efficient for material removal, while white stones are less abrasive for finer adjustments.
Instrument Handling
- A modified pen grasp ensures optimal control and stability when restoring Class IV preparations.
Cavity Preparation Examination
- Before restoration, ensure cleanliness and dryness of the cavity prep while locating retention grooves.
Calcium Hydroxide Application
- Calcium hydroxide is applied over dentin to protect the pulp, ensuring excess is removed after it sets.
Etching Procedure
- Thorough cleaning with a non-fluoride prophy paste is essential before etching.
- An etching procedure involves using a cotton pellet dipped in etch liquid, applied to enamel for one minute.
Bonding Process
- A thin, even layer of bonding material must be applied to etched surfaces and cured for 15-20 seconds.
Measurement for Composite Placement
- A metric ruler or Boley gauge is used to measure the tooth mesiodistally prior to composite application.
Trimming Techniques
- Trimming should always be done away from the tooth to prevent accidental damage.
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Description
Test your knowledge on Class IV composite restorations with these flashcards. Covering retentive features, restoration details, and cutting techniques, this quiz is essential for dental students. Enhance your understanding of cavity preparations and the materials involved.
