Restorative Dentistry Principles Flashcards

What does 'occlusal vertical dimension' (OVD) refer to in the context of complete denture construction?

Answer: The face height when the teeth (or denture teeth) are in occlusal contact — the distance between fixed reference points on the face with the jaws closed in maximum intercuspation

OVD is the vertical face height measured between fixed reference points (typically base of nose and chin) when the teeth/denture teeth are in occlusal contact. It must be correctly determined to ensure aesthetics, comfort, and function.

When selecting the shade for a porcelain-fused-to-metal (PFM) or all-ceramic crown, which of the following is the CORRECT approach?

Answer: Shade matching should be done in natural daylight or standardised lighting, with teeth moist, before preparation, using a shade guide held adjacent to the teeth and with the surrounding teeth visible for comparison

Accurate shade matching requires natural or standardised light, moist teeth (dehydrated teeth are falsely light), performing shade selection before cavity preparation (to avoid patient fatigue and altered tooth appearance), and comparing the shade guide to the adjacent natural teeth.

A patient requires an anterior tooth extracted due to root fracture. They are concerned about aesthetics during healing. Which of the following is the MOST appropriate IMMEDIATE replacement option?

Answer: An immediate partial denture (IPD) or immediate temporary bridge to maintain aesthetics while the site heals

An immediate partial denture (acrylic RPD) or an immediate temporary adhesive bridge is fabricated before extraction and fitted at the time of extraction — providing aesthetic replacement while the extraction site heals and definitive plans are made.

What does the term 'ferrule effect' mean in the context of post and core crown restorations?

Answer: A band of sound tooth structure circumferentially embraced by the crown margin that improves fracture resistance of the restored tooth

The ferrule effect refers to the protective band of sound dentine that the crown margin engages around the entire circumference of the tooth. This 'ferrule' resists the wedging and splitting forces applied to the post-retained crown during function.

Which type of impression material is used for taking accurate definitive impressions for crowns and fixed prostheses in the UK?

Answer: Addition-cured silicone (polyvinylsiloxane) or polyether impression materials, which provide dimensional stability and high accuracy

Addition-cured silicones (polyvinylsiloxane, A-silicone, PVS) and polyethers are the gold standard elastic impression materials for crown and bridge work due to their dimensional stability, high accuracy, tear resistance, and compatibility with die stone.

A patient presents with tooth surface loss affecting multiple teeth with a 'cupped out' appearance on the occlusal surfaces and a history of reflux disease. What is the most likely aetiology and appropriate management approach?

Answer: Erosion from intrinsic acid (gastro-oesophageal reflux disease, GORD) — manage by addressing the acid source, applying preventive measures, and monitoring or restoring if necessary

Cupped-out occlusal lesions in the context of acid reflux are pathognomonic of erosion from intrinsic (gastric) acid. Management requires addressing the medical cause, applying preventive strategies, and restoring lost tissue when necessary.