CHAPTER 8: CLINICAL TECHNIQUE FOR CLASS I-II RESTORATION

Q: Why use local anesthesia in composite placement?

A: Provides comfort, reduces salivation, and improves bonding conditions.

How should the tooth be cleaned before composite placement?

A: With pumice slurry — avoid flavored, glycerin-based, or fluoride-containing prophy pastes.

Q: Why avoid certain prophy pastes before bonding?

A: They contaminate the surface and weaken adhesive bonding.

Q: When should shade be selected and why?

A: Before drying the tooth; dehydration makes teeth appear lighter.

Q: Effect of contamination after etching?

A: Significantly reduces bond strength and degrades composite properties.

Q: Why check occlusion before tooth preparation?

A: Avoid placing occlusal contacts on cavosurface/restoration margins and guide final contact adjustment.

Q: Goals of Class I composite prep?

A: Access lesion, remove faulty structure, create convenience form, conserve tooth structure.

NO mechanical retention features required bc bonding provides retention

no need to bevel occlusal margins bc enamel rods are already exposed.

Q: Recommended burs for small/moderate preps?

A: Small round or elongated pear-shaped burs (carbide or diamond) with round features.

Q: Shape of cavosurface margin in conservative preps?

A: Flared or obtuse.

Q: Preferred bur for extensive lesions?

A: Elongated pear-shaped bur with round features, parallel to long axis.

Q: Recommended pulpal floor depth?

A: About 0.2 mm inside carious DEJ or 1.5–2 mm flat depth.

Q: Minimum remaining tooth structure at marginal ridge?

A: Premolars: ≥1.5 mm; Molars: ≈2 mm.

If RDT = 0.5–1.5 mm, what base is used?

A: Resin-modified glass ionomer (RMGI).

Q: If RDT < 0.5 mm, what is used?

A: Calcium hydroxide liner + RMGI base.

Q: Direct pulp capping materials?

A: Calcium hydroxide or MTA + cover with RMGI base.

Q: Maximum thickness per increment?

A: 2 mm for conventional composites.

Q: What is the C-factor in Class I prep and why is it important?

A: 5:1 — high shrinkage stress risk, especially at pulpal wall.

Q: What is the sandwich technique?

A: RMGI under composite to bond to dentin, release fluoride, and possibly reduce shrinkage stress.

Q: Thickness limit for bulk-fill increments?

A: Up to 4 mm (varies by manufacturer).

A: One increment per cusp, shaped against cusp inclines, then cured.

Q: Main concerns with bulk-fill composites?

A: Possible poor adaptation and increased wear; limited long-term evidence.

Q1: What is the main reason for using incremental layering in composite restorations?

A: To minimize polymerization shrinkage and ensure complete curing.

Q3: Why is it important to air-thin the bonding agent before curing?

Q3: Why is it important to air-thin the bonding agent before curing?

Q5: What is the preferred isolation method for Class I composite restorations?

A: Rubber dam isolation.

In which situation would you need a matrix band for a Class I composite preparation?

A: Only if the preparation extends into proximal surfaces, making it a Class II.

Q: Why is the presence of enamel periphery important in Class II composite restorations?

A: Because bonding to enamel is more predictable and stronger than bonding to dentin, especially at the gingival wall.

Q: What role does preoperative wedging play?

A: It helps separate teeth to reestablish proper proximal contact when restoring with composite.

Q: What are the three main goals of tooth preparation in Class II direct composites?

A: 1) Access the defective structure; 2) Remove caries, faulty restoration, or base materials; 3) Create convenience form for restoration.

Q: What instruments are typically used for removing carious tissue in small Class II composite restorations?

A: Small round or elongated pear-shaped diamond burs.

Q: Describe the “box-only” Class II preparation design.

A: A proximal box preparation only, when occlusal surfaces are sound, prepared parallel to the tooth’s long axis to remove proximal caries.

Q: When is the facial or lingual slot preparation indicated?

A: When proximal lesion access can be gained from facial or lingual direction rather than gingivally through the marginal ridge.

Q: What are the characteristics of the margins in facial/lingual slot preparations?

A: Cavosurface margins are 90 degrees or greater; marginal ridge must not be undermined.

Q: How do moderate to large Class II composite preparations differ from small ones?

A: They resemble traditional amalgam preparations and may include an occlusal step and proximal box.

Q: What is the significance of the dentinoenamel junction (DEJ) in proximal box preparations?

A: It serves as a guide for the pulpal floor depth and the outline of the proximal box.

Q: What burs are typically used to prepare the proximal box?

A: No. 330 or No. 245 diamond burs.

Q: How should the facial and lingual walls be prepared in the proximal box?

A: To have at least 90-degree cavosurface margins, preferably more obtuse, and parallel to the long axis of the tooth.

Q: Why are bevels rarely used on proximal box margins in Class II composite preparations?

A: Because bevels make restoration more difficult and viscous composites are harder to adapt there.

A: Because enamel rods are already exposed and bevels make finishing more difficult without providing significant bonding benefits.

Q: What matrix types are preferred for Class II composite restorations?

A: Ultrathin metal matrix bands or precontoured sectional metallic matrices.

Q: What are the advantages of sectional matrix systems with bitine rings?

A: They stabilize the matrix and provide tooth separation, simplifying proximal contouring and contact.

Q: What is the purpose of the wedge during matrix placement?

A: To hold the matrix in position, separate teeth slightly, and prevent gingival overhang.

Q: What is the purpose of sculpting the marginal ridge during composite insertion?

A: To achieve proper anatomy and minimize the need for excessive finishing.

Q: How can preheating composite material help during placement?

A: It reduces viscosity, improving adaptation and reducing microleakage.

Q: Describe the finishing procedure after Class II composite restoration.

A: Use carbide burs and abrasive discs to remove excess and shape anatomy; surgical blade for gingival overhangs; polishing with points, cups, or brushes.

Q: What is the advantage of holding the matrix in physical contact during curing of the proximal increment?

A: It ensures a tight proximal contact by preventing composite displacement before curing.

Q: What is the primary retention form for very large Class II composite restorations?

A: Micro-mechanical bonding to enamel and dentin.

Q: Why are secondary retention features necessary in extensive Class II composite restorations?

A: Because of decreased tooth structure for bonding and the need to better retain the composite.

Q: Name some secondary retention features used in extensive Class II composite restorations.

A: Grooves, coves, and slots.

Q: When should a cusp be reduced and capped with composite?

A: If occlusal outline extends more than two-thirds from a primary groove to a cusp tip or if the cusp is weakened due to dentin loss.

Q: Where should grooves, coves, or slots be placed for retention?

A: Strategically in dentin to maintain dentinal support and avoid pulpal involvement.

Q: What challenges does matrix placement present in extensive Class II restorations?

A: More missing tooth structure, possible subgingival margins, and the need for proper burnishing and adaptation.

Q: What should be done during light curing to ensure proper proximal contact?

A: Use a hand instrument to hold the matrix against the adjacent tooth during curing.

Q: Why should dual-cured composites be light cured after placement?

A: To ensure complete polymerization and optimal properties.

Q: What compatibility issues can occur between adhesives and self-cured composites?

A: Acidic monomers in simplified adhesives can scavenge activators in self-cure composites, inhibiting polymerization.

soution: A: Using chemical catalysts mixed with light-cured adhesives to prevent activator scavenging.

What post-restoration protocol is recommended for patients with extensive composite restorations?

A: Frequent recall visits due to the potentially limited longevity of large composite restorations.