ABO ABO Periodontics and Interdisciplinary Treatment 1 — Questions and Answers
Question 1: Orthodontic tooth movement is contraindicated in areas with active periodontitis primarily because:
- Brackets cannot bond to periodontally involved teeth
- Moving teeth through infected periodontium accelerates alveolar bone loss (Correct answer)
- Periodontal ligament fibers interfere with bracket placement
- Gingival recession always causes root exposure
Correct answer: Moving teeth through infected periodontium accelerates alveolar bone loss
Active periodontal infection in the alveolar bone combined with orthodontic forces accelerates bone resorption, worsening the patient's periodontal prognosis.
Question 2: Orthodontic intrusion of an overerupted tooth with chronic periodontitis can help by:
- Eliminating the need for periodontal surgery entirely
- Reducing the infrabony defect depth and improving the osseous topography (Correct answer)
- Increasing clinical crown length
- Eliminating pocket depths immediately
Correct answer: Reducing the infrabony defect depth and improving the osseous topography
Intrusion of periodontally involved over-erupted teeth can improve infrabony defect geometry, making subsequent periodontal surgery more predictable.
Question 3: Before starting orthodontic treatment in a patient with a history of periodontitis, the MOST important prerequisite is:
- Completion of all restorative work
- Achievement of periodontal stability (BOP < 20%, controlled disease) (Correct answer)
- Extraction of third molars
- Whitening of anterior teeth
Correct answer: Achievement of periodontal stability (BOP < 20%, controlled disease)
Periodontal stability with minimal bleeding on probing confirms that active infection is controlled, making it safe to initiate orthodontic forces.
Question 4: Patients with a thin gingival biotype are at higher risk for which complication during orthodontic treatment?
- Accelerated dental caries
- Gingival recession, especially when moving teeth facially (Correct answer)
- Ankylosis of posterior teeth
- Enamel cracking during debonding
Correct answer: Gingival recession, especially when moving teeth facially
Thin gingival tissue has reduced capacity to withstand orthodontic forces, making facial tooth movement more likely to cause gingival recession.
Question 5: Orthodontically forced eruption (extrusion) of a fractured tooth prior to crown placement serves to:
- Increase alveolar bone density only
- Bring the fracture margin supragingivally and develop bone/tissue for restorative margins (Correct answer)
- Accelerate root formation
- Reduce root resorption risk
Correct answer: Bring the fracture margin supragingivally and develop bone/tissue for restorative margins
Forced eruption brings the fracture line coronal to the alveolar crest and gingival margin, providing adequate tooth structure and biological width for a crown.
Question 6: The term 'biological width' in restorative-orthodontic interdisciplinary care refers to:
- The thickness of the alveolar bone plate
- The combined dimension of the junctional epithelium and supracrestal connective tissue attachment (Correct answer)
- The distance between adjacent tooth contacts
- The thickness of the gingival margin
Correct answer: The combined dimension of the junctional epithelium and supracrestal connective tissue attachment
Biological width (~2 mm) is the physiologic space occupied by the junctional epithelium (~1 mm) and supracrestal connective tissue (~1 mm) that must be respected by restorative margins.
ABO ABO Periodontics and Interdisciplinary Treatment 1
Orthodontic tooth movement is contraindicated in areas with active periodontitis primarily because: