Minyoung_Choi7 Operative II: Insertion and Light Curing of the Composite (reading)

Q: Is a matrix usually necessary for Class I direct composite restorations?

A: No, a matrix is usually not necessary, even when facial and lingual surface grooves are included.

Q: What tools may be used to place composite material incrementally?

A: Composite insertion hand instruments or a compule.

Q: Why is incremental placement and curing of composite important?

A: To ensure maximum polymerization and possibly reduce the negative effects of polymerization shrinkage.

Q: What may happen if large increments or bulk filling are used?

A: It may compromise polymerization due to inadequate depth of cure.

Q: What does the term "C-factor" refer to?

A: The ratio of bonded to unbonded surfaces in a tooth preparation and restoration.

Q: What is the C-factor of a typical Class I tooth preparation?

A: 5/1 – five bonded surfaces vs. one unbonded surface (occlusal).

Q: How does a high C-factor affect polymerization stress?

A: It increases the potential for shrinkage stress because bonded surfaces restrict shrinkage deformation.

Q: Which interface is most likely affected by high C-factor stress?

A: The pulpal wall interface.

Q: How can the negative effects of high C-factor be reduced?

A: By incrementally inserting and light curing the composite.

Q: Why were RMGI or flowable composite liners thought to reduce shrinkage stress?

A: Due to their favorable elastic modulus, which could absorb stresses more effectively.

Q: Are the benefits of RMGI/flowable liners supported by current clinical evidence?

A: No, current clinical evidence does not support those claims.

Q: What is the "sandwich" technique in composite restorations?

A: Placement of composite over an RMGI material.

Q: What is one advantage of using RMGI in the sandwich technique?

A: It bonds to dentin without the need for dental adhesive.

Q: What is another potential benefit of RMGI in deep gingival preparations?

A: Fluoride release and bonding to dentin may improve the seal.

Q: How might the elastic modulus of RMGI help in restorations?

A: It may reduce the effects of polymerization shrinkage stresses.

Q: Are the suggested advantages of the sandwich technique conclusive?

A: No, they are controversial due to lack of longitudinal clinical trial evidence.

Q: Why should posterior composites be placed incrementally, regardless of shrinkage stress?

A: To ensure proper light curing and correct anatomic development.

Q: What should guide composite placement in Class I restorations?

A: The anatomic references of the occlusal unprepared tooth structure.

Q: How should very deep parts of the preparation be restored?

A: In increments of no more than 2 mm in thickness.

Q: What technique is used for placing the enamel (occlusal) layer?

A: The anatomic layering technique.

Q: How is composite shaped before curing in the anatomic layering technique?

A: It is shaped to restore occlusal anatomy before light curing.

Q: How is composite typically placed during occlusal layering?

A: One increment per cusp is placed and cured at a time.

Q: How can cusp inclines aid in composite placement?

A: They serve as visual guides to shape natural contours before curing.

Q: What are the benefits of shaping composite using anatomic references?

A: It minimizes the need for contouring and finishing after curing.

Q: How does this technique protect adjacent enamel margins?

A: It minimizes rotary instrument use to remove excess composite.

Q: What instruments can be used with the anatomic layering technique?

A: Composite hand instruments, fine spatulas, and explorer tines.

Q: What is the role of microbrushes in composite placement?

A: To smooth uncured composite against margins (not saturated with adhesives).

Q: When can final finishing of the restoration be done?

A: Immediately after the last increment is fully cured.

Q: What are bulk-fill composites?

A: Composites that can be placed in larger increments for faster procedures.

Q: What are the two types of bulk-fill composites?

A: Flowable base bulk-fill and full-body bulk-fill composites.

Q: What is the role of flowable base bulk-fill composites?

A: Used only for dentin replacement; a conventional composite is still needed for the occlusal increment.

Q: What can full-body bulk-fill composites replace?

A: Both dentin and enamel in a single increment.

Q: What is one advantage of bulk-fill composites?

A: They allow placement in increments up to 4 mm, saving time.

Q: What concerns have in vitro studies raised about bulk-fill techniques?

A: Possible compromised internal adaptation and increased wear.

Q: Why should bulk-fill composites be used cautiously?

A: Lack of long-term clinical performance data.

Q: What is a drawback of bulk filling regarding occlusal anatomy?

A: It may limit the operator’s ability to carve anatomy before curing.