Across
- 3. A flexible metal band used to form a temporary wall around a tooth during a restorative procedure, particularly for Class II preparations, to contain the restorative material.
- 5. Wooden or plastic triangular inserts placed into the gingival embrasure to secure the matrix band against the tooth and prevent overhanging restorative material at the gingival margin.
- 6. The expansion or contraction of dental amalgam during its setting process. Significant changes can lead to open gaps at margins (contraction) or pressure on cusps/fracture (expansion).
- 9. A universal retainer used to hold a matrix band securely in place around a tooth.
- 10. An alloy, one of the constituents of which is mercury. In dentistry, it's a direct restorative material formed by mixing an alloy powder with liquid mercury.
- 11. The reaction product of mercury with silver ($\text{Ag}_2\text{Hg}_3$). It is a strong and corrosion-resistant phase in the set amalgam.
- 14. amalgam alloys containing a higher percentage of copper (typically 13-30%) compared to traditional low-copper amalgams. These formulations minimize or eliminate the gamma-2 phase.
- 15. An alloy powder that is a mixture of two or more different particle shapes, typically lathe-cut and spherical.
- 16. The unreacted silver-tin alloy phase ($\text{Ag}_3\text{Sn}$) in dental amalgam. It is the strongest and most corrosion-resistant phase.
- 17. A surface discoloration or dulling of the amalgam restoration due to oxidation from contact with substances like oxygen, chlorides, and sulfides. It is generally not destructive to the material's integrity.
- 18. A destructive chemical reaction (oxidation) of a metal with its environment, leading to the breakdown and weakening of the amalgam restoration. It can also cause staining.
- 19. Alloy particles that are spherical in shape, typically produced by atomizing molten alloy into an inert gas. These alloys require less mercury and set faster.
Down
- 1. Older formulations of dental amalgam alloys with a lower percentage of copper (typically 4-6%), which allows for the formation of the weak and corrodible gamma-2 phase.
- 2. Irregularly shaped alloy particles formed by milling or shaving an ingot of the alloy.
- 4. The gradual change in shape or deformation of an amalgam restoration under constant compressive stress (e.g., from opposing dentition) over time. It is associated with marginal deterioration.
- 7. The reaction product of mercury with tin ($\text{Sn}_8\text{Hg}$). This phase is weak, prone to creep, and readily corrodes, contributing to breakdown in low-copper amalgams.
- 8. The ability of a material to conduct heat. Amalgam is a good conductor of heat and cold, which can necessitate a base or liner in deeper cavity preparations to protect the pulp.
- 12. The process of mixing liquid mercury with the dental alloy powder, resulting in a chemical reaction that forms dental amalgam. Also refers to the crystallization process during setting.
- 13. An optional component in some dental amalgam alloys, used to reduce the oxidation of other metals (preventing galvanic reactions). However, low-copper amalgams containing zinc are prone to delayed expansion if contaminated with moisture.