Which instrument is used to modify habit appliances such as cribs?

• A. adams crib
• B. twinblock appliance
• C. roberts retractor
• D. adams pliers

Answer: (A)

The idea being tested is how habit-breaking orthodontic devices work. An Adams crib is a fixed habit appliance designed specifically to modify sucking or tongue-thrust habits by occupying space in the palate and interfering with the habit pattern. By wearing it, the patient’s habitual activity is redirected, helping to correct associated malocclusions as the dentition develops. This makes Adams crib the best answer, because it is the appliance itself aimed at changing the habit. The other options serve different roles: twinblock is a functional appliance for jaw development rather than habit modification, Roberts retractor is a surgical/soft-tissue retractor, and Adams pliers are tools used to adjust appliances rather than to modify habits directly.