Ceramic Application & Contouring Flashcards

When building proximal contacts in ceramic, the ceramist must ensure contact is located:

Answer: At the height of contour in the middle third of the proximal surface

Proximal contacts are ideally in the middle third (or junction of middle and incisal thirds for anteriors) to protect the interdental papilla and allow natural embrasure form.

Which ceramic mixing technique minimizes air bubble incorporation during porcelain preparation?

Answer: Folding and pressing the mixture against the pad using a flat spatula with gentle strokes

Folding and pressing ceramic against a mixing pad incorporates moisture evenly while minimizing air entrapment compared to stirring or shaking.

A fired ceramic crown shows a gray shadow visible through the facial surface. The most probable cause is:

Answer: Metal show-through due to inadequate opaque coverage or insufficient ceramic thickness

Gray shadow is the classic sign of metal show-through, caused by too little opaque or body ceramic that allows the dark metal substructure to be visible through the translucent porcelain.

When contouring a full-contour zirconia crown using diamond burs chairside, which cooling method prevents microcrack formation in the zirconia surface?

Answer: Continuous water cooling during all adjustment procedures

Continuous water cooling prevents frictional heat from inducing phase transformation stress in zirconia, which can initiate surface microcracks that compromise restoration integrity.

The 'condensation' step in ceramic buildup involves which action?

Answer: Compressing ceramic particles together using vibration or blotting to increase density and reduce porosity

Condensation removes excess liquid and compresses particles together, increasing ceramic density and reducing porosity in the fired restoration.

Which surface texture technique, applied before final glaze, best simulates the natural perikymata texture of enamel on an anterior ceramic crown?

Answer: Adding horizontal fine-line grooves with a pointed instrument parallel to the incisal edge

Fine horizontal grooves etched with a pointed instrument before glazing replicate the natural perikymata ridges present on natural enamel surfaces for a lifelike appearance.

When fabricating a three-unit ceramic bridge, where should the ceramist direct particular attention during the pontic contour phase?

Answer: The tissue surface of the pontic and its ridge relationship

The pontic's tissue surface contour and ridge relationship are critical for tissue health, esthetics, and cleansability; an ovate or modified ridge lap design is commonly used.