ABO Retention and Stability Flashcards

The Ricketts analysis dimension most predictive of post-treatment lip stability is the:

Answer: E-line (esthetic plane) relationship of the lips

Ricketts' E-line measures lip position relative to the nose and chin, and it is a key predictor of facial soft-tissue stability after orthodontic treatment.

Which statement about lower incisor position and long-term stability is most supported by orthodontic evidence?

Answer: Maintaining lower incisors near their pre-treatment position improves stability

Research consistently shows that keeping lower incisor positions close to pre-treatment values reduces the risk of crowding relapse.

Nighttime-only retainer wear is typically appropriate beginning at which stage?

Answer: After approximately one year of full-time wear

After approximately one year of full-time retainer wear to allow periodontal reorganization, most patients can transition to nighttime-only wear.

Canine-to-canine intercanine width changes during orthodontic treatment have the highest relapse rate because:

Answer: The intercanine dimension is closely controlled by the surrounding musculature and pre-treatment anatomy

The intercanine width is strongly dictated by the functional envelope of the muscles and pre-existing skeletal architecture, making changes highly unstable.

Which radiographic finding on the ABO case presentation may indicate a problem with long-term stability?

Answer: Significant root resorption of anterior teeth

Significant root resorption reduces root surface area available for the periodontal ligament, potentially compromising tooth support and increasing mobility.

The term 'post-retention stability' in orthodontics refers to:

Answer: Long-term maintenance of corrected tooth positions after retainers are discontinued

Post-retention stability describes how well the corrected tooth positions are maintained after the patient ceases retainer use.