RDA Dental Specialties Assisting (Orthodontics, Periodontics, Oral Surgery, Endodontics, and Prosthodontics) — Questions and Answers
Question 1: During an orthodontic appointment, a dental assistant uses a scaler to remove excess bonding material around a newly placed bracket. This instrument technique is called:
- Coronal polishing
- Flash removal (Correct answer)
- Band seating
- Torquing
Correct answer: Flash removal
After brackets are bonded to teeth, excess adhesive ('flash') that squeezes out from under the bracket base must be removed before the bonding agent is light-cured or while it is still pliable. This process is called flash removal and is a routine expanded duty in orthodontic assisting.
Question 2: In periodontal surgery, a periosteal elevator is used to:
- Remove calculus from the root surface
- Reflect and retract the mucoperiosteal flap away from the bone (Correct answer)
- Place sutures after surgery
- Measure pocket depth around each tooth
Correct answer: Reflect and retract the mucoperiosteal flap away from the bone
A periosteal elevator (e.g., Molt #9) is designed to separate and reflect the mucoperiosteal flap—the combined periosteum and overlying gingiva—from the underlying alveolar bone during flap surgery. This provides access for osseous reshaping or grafting procedures.
Question 3: Which instrument is used during a tooth extraction to loosen the periodontal ligament fibers and expand the alveolar socket before forceps are applied?
- Curette
- Rongeur
- Elevator (Correct answer)
- Periosteal elevator
Correct answer: Elevator
Elevators (e.g., straight elevator, Cryer elevator) are placed between the tooth and the socket wall to sever periodontal ligament fibers and expand (luxate) the alveolus, making forceps delivery easier and safer. Rongeurs trim bone after extraction; curettes are periodontal instruments.
Question 4: During root canal therapy, a rubber dam is placed primarily to:
- Improve patient comfort by keeping the mouth open
- Isolate the field and prevent contamination of the canal with oral bacteria (Correct answer)
- Retract the cheek for better operator visibility
- Reduce the amount of anesthetic needed
Correct answer: Isolate the field and prevent contamination of the canal with oral bacteria
The rubber dam isolates the tooth being treated, keeping saliva and oral bacteria out of the root canal system. Endodontic success depends on achieving and maintaining asepsis throughout the procedure. The rubber dam is considered mandatory for safe endodontic treatment.
Question 5: A final impression for a full-coverage crown is most commonly taken using a:
- Alginate (irreversible hydrocolloid) in a stock tray
- Zinc oxide eugenol (ZOE) impression paste
- Polyvinyl siloxane (PVS) in a custom or triple tray (Correct answer)
- Plaster of Paris in a full-arch tray
Correct answer: Polyvinyl siloxane (PVS) in a custom or triple tray
Polyvinyl siloxane (PVS), also called vinyl polysiloxane, is the standard material for final (definitive) crown and bridge impressions due to its dimensional accuracy, elastic recovery, and tear resistance. Alginate is used for study models and opposing arch impressions, not final prosthetic impressions.
Question 6: After a tooth extraction, the patient is instructed to bite on gauze for 30–45 minutes. The primary reason for this instruction is to:
- Prevent the tongue from touching the socket
- Apply direct pressure to promote clot formation and hemostasis (Correct answer)
- Keep the socket moist so the bone does not dry out
- Reduce postoperative swelling
Correct answer: Apply direct pressure to promote clot formation and hemostasis
Direct pressure on the extraction socket compresses the blood vessels and promotes platelet aggregation, which is the first step in hemostasis and clot formation. A stable blood clot is essential for normal healing and prevention of dry socket (alveolar osteitis).
RDA Dental Specialties Assisting (Orthodontics, Periodontics, Oral Surgery, Endodontics, and Prosthodontics)
During an orthodontic appointment, a dental assistant uses a scaler to remove excess bonding material around a newly placed bracket.
This instrument technique is called: