Clinical Dental Sciences Flashcards

Which instrument design is most appropriate for initial negotiation of a calcified or curved root canal?

Answer: ISO size 10 stainless steel K-file

A size 10 stainless steel K-file is small, flexible and appropriate for initial exploration of calcified or curved canals where larger instruments risk ledging or transportation.

The recommended minimum ceramic thickness for an all-ceramic posterior crown to prevent fracture is approximately:

Answer: 1.5–2.0 mm

Current clinical guidelines recommend a minimum occlusal ceramic thickness of 1.5–2.0 mm for all-ceramic posterior crowns to provide sufficient fracture resistance under occlusal loading.

The 'C-factor' in composite dentistry refers to:

Answer: The ratio of bonded to unbonded surfaces affecting polymerisation shrinkage stress

The configuration factor (C-factor) is the ratio of bonded to unbonded surfaces; a high C-factor (e.g. in a Class I box) concentrates polymerisation shrinkage stress on bonded walls.

When splinting periodontally involved teeth, the most important biomechanical requirement is:

Answer: Ensuring the splint does not interfere with oral hygiene access

Regardless of the splint type, access for interdental cleaning must be maintained to control plaque around compromised teeth; poor hygiene access accelerates periodontal breakdown.

In caries risk assessment, which factor contributes most significantly to high caries risk categorisation?

Answer: Presence of active white spot lesions and high sucrose intake

Active demineralisation (white spot lesions) combined with frequent fermentable carbohydrate intake indicates current disease activity and high future caries risk.

Which type of tooth movement is most energy-efficient and causes the least root resorption in orthodontics?

Answer: Tipping

Tipping (crown movement with fulcrum at the apical third) requires the least force and produces less root resorption than bodily movement, though it produces less controlled movement.