Clinical Procedures & Protocols Flashcards

During ceramic layering, what is the consequence of applying an excessively thick layer of dentin porcelain in a single build-up?

Answer: Increased risk of cracking and delamination during firing

Thick single-layer applications create differential shrinkage stresses during firing that can cause cracking, delamination, or warping of the ceramic.

A patient presents with a ceramic veneer that has debonded six months post-placement. What clinical factor should the ceramist investigate in the remake protocol?

Answer: Surface preparation protocol and bonding system compatibility

Early debonding typically indicates inadequate enamel etching, incompatible bonding systems, or insufficient ceramic surface conditioning (HF etching/silanation).

What is the significance of the 'critical angle' in porcelain contouring during occlusal adjustment?

Answer: It defines the point at which grinding breaks through the glaze into the body ceramic

Once grinding penetrates the glaze layer into body ceramic, repolishing or refiring is required because rough ceramic surfaces abrade opposing dentition.

In an implant-supported ceramic crown case, how does the absence of a periodontal ligament affect the ceramist's occlusal design?

Answer: Lighter occlusal contacts are recommended due to lack of proprioceptive feedback and shock absorption

Implants lack the PDL's proprioceptive feedback and viscoelastic shock absorption, requiring lighter occlusal loading to prevent ceramic fracture and implant overload.

Which protocol should be followed when a ceramic restoration requires post-delivery adjustments that penetrate through the glazed surface?

Answer: Polish with diamond-impregnated rubber points in sequence ending with fine grit, then consider refiring

After grinding through glaze, progressive diamond polishing can restore surface smoothness, with refiring as the optimal option for large adjustment areas.

When fabricating ceramic restorations for a patient with a deep vertical overlap (overbite), which incisal edge design consideration is most critical?

Answer: Incisal clearance verification in excursive movements to prevent fracture

Deep overbite cases require careful verification of adequate ceramic thickness and clearance during protrusive movements to prevent fracture under functional loading.

A ceramist notices persistent porosity in fired ceramic despite following standard condensation protocols. What is the most likely cause?

Answer: Inadequate vibration during condensation trapping air bubbles

Insufficient vibration during slurry condensation fails to expel entrapped air, leading to porosity that weakens the ceramic and creates aesthetic defects after firing.