Orthodontics · single question
Which fibres are responsible for rotational relapse after orthodontic treatment?
Show answer and explanation
Correct answer: C. Transseptal (supracrestal) fibres
- A. Incorrect. Alveolar crest fibres of the PDL resist intrusive and lateral forces and remodel with bone relatively quickly.
- B. Incorrect. Horizontal PDL fibres resist lateral forces and reorganise within weeks.
- C. Correct. The transseptal/supracrestal gingival fibres run from cementum over the alveolar crest to the adjacent tooth. They remodel very slowly and continue to exert elastic recoil for years, causing rotational relapse. This is why circumferential supracrestal fiberotomy is performed for severe rotations.
- D. Incorrect. Apical PDL fibres resist extrusive forces.