Free EFDA Restorative & Prosthodontic Procedures Questions and Answers — Questions and Answers
Question 1: What is the primary purpose of a dental dam in restorative procedures?
- To improve the patient's comfort during the procedure
- To isolate the tooth and protect adjacent tissues (Correct answer)
- To reduce the need for local anesthesia
- To speed up the curing time of composite materials
Correct answer: To isolate the tooth and protect adjacent tissues
The primary purpose of a dental dam in restorative procedures is to isolate the tooth being worked on from the rest of the oral cavity. This isolation keeps the operating field dry and free from saliva and blood, while also protecting adjacent soft tissues like the tongue, cheeks, and gums from instruments and materials. It creates a clean and safe environment for optimal treatment.
Question 2: Which material is most commonly used for temporary crowns?
- Gold alloy
- Porcelain
- Acrylic resin (Correct answer)
- Zirconia
Correct answer: Acrylic resin
Acrylic resin is the most commonly used material for temporary crowns due to its ease of manipulation, relatively low cost, and ability to be quickly fabricated chairside. It provides adequate strength and esthetics for short-term use while a permanent crown is being made. Other materials like gold, porcelain, and zirconia are typically used for permanent restorations.
Question 3: What is the correct sequence for placing a composite restoration?
- Etch, bond, cure, place composite
- Bond, etch, place composite, cure
- Etch, rinse, bond, place composite, cure (Correct answer)
- Place composite, etch, bond, cure
Correct answer: Etch, rinse, bond, place composite, cure
The correct sequence for placing a composite restoration begins with etching the tooth surface to create microscopic porosities for mechanical retention. This is followed by rinsing to remove the etchant, then applying a bonding agent to create a strong adhesive layer. Finally, the composite material is placed and then light-cured to harden it.
Question 4: Why is proper matrix band placement critical in Class II restorations?
- To reduce chair time
- To ensure proper contact and contour with adjacent teeth (Correct answer)
- To eliminate the need for polishing
- To make removal of excess material easier
Correct answer: To ensure proper contact and contour with adjacent teeth
In Class II restorations, which involve the proximal surfaces of posterior teeth, proper matrix band placement is critical for establishing the correct anatomical form. The matrix band acts as a temporary wall, allowing the restorative material to be condensed against it, thereby ensuring proper contact with the adjacent tooth and recreating the natural contour. This prevents food impaction and promotes periodontal health.
Question 5: Which instrument is used to check occlusal contacts after crown placement?
- Explorer
- Articulating paper (Correct answer)
- Periodontal probe
- Spoon excavator
Correct answer: Articulating paper
Articulating paper is a thin, colored paper used to mark areas of premature or excessive contact between opposing teeth, especially after placing a new restoration like a crown. When the patient bites down on the paper, it leaves a colored mark on the high spots, guiding the dentist to adjust the occlusion for proper bite and comfort. This ensures the restoration integrates correctly with the patient's natural bite.
Question 6: What is the ideal moisture condition for dentin during bonding?
- Bone-dry
- Slightly moist (glossy but not pooled) (Correct answer)
- Soaked with water
- Coated with saliva
Correct answer: Slightly moist (glossy but not pooled)
For optimal dentin bonding, the tooth surface should be slightly moist, often described as 'glossy but not pooled.' This condition helps to prevent the collapse of collagen fibers in the dentin, allowing the bonding agent to penetrate effectively and create a strong hybrid layer. If the dentin is too dry, the collagen fibers collapse, reducing bond strength; if too wet, the bonding agent can be diluted.
Question 7: Which factor most affects the setting time of dental cements?
- Room lighting
- Humidity levels
- Temperature of the mixing slab (Correct answer)
- Patient's age
Correct answer: Temperature of the mixing slab
The setting time of many dental cements is significantly influenced by temperature. A cooler mixing slab will slow down the chemical reaction, extending the working time, which can be beneficial for complex procedures. Conversely, a warmer slab will accelerate the setting time, reducing the working time available to the dental professional.
Question 8: What is the purpose of a gingival retraction cord?
- To stop bleeding during surgery
- To displace gingiva and expose the margin (Correct answer)
- To whiten the gums
- To numb the tooth
Correct answer: To displace gingiva and expose the margin
Gingival retraction cord is placed into the sulcus (the space between the tooth and the gum) to temporarily push the gingival tissue away from the tooth. This creates a clear space, exposing the preparation margin for impression taking or bonding procedures. This ensures that the restorative material or impression accurately captures the tooth's full contour, leading to a well-fitting restoration.
Question 9: Which characteristic distinguishes a Type III gold alloy from a Type IV?
- Type III is for orthodontic appliances
- Type IV has higher hardness for crowns/bridges (Correct answer)
- Type III contains platinum
- Type IV cannot be polished
Correct answer: Type IV has higher hardness for crowns/bridges
Gold alloys are classified into types based on their hardness and strength, which dictate their clinical application. Type IV gold alloys are the hardest and strongest, making them suitable for high-stress applications like crowns, bridges, and partial denture frameworks. Type III alloys are medium hardness, typically used for full gold crowns and inlays, but not as robust as Type IV for extensive prostheses.
Free EFDA Restorative & Prosthodontic Procedures Questions and Answers
What is the primary purpose of a dental dam in restorative procedures?