Cosmetic Dentistry-Ceramic Crowns Can Make Your Smile Beautiful!

All Ceramic Crowns are fabricated entirely out of a glass-like compound such as porcelain. There are 2 ceramic materials that are the clinicians’ favorites today: lithium disilcate and zirconia.

"Lithium disilicate restorations are the most esthetic restorations in dentistry today," states Dr. Anna Lee.  These restorations match the esthetic characteristics of natural teeth very closely.  Multiple-unit restorations (fixed bridges) are not recommended at this time.

Lithium disilicate restorations are good choices for single unit restorations, both anterior and posterior teeth.

Zirconia restorations are strong restorations but are not as esthetic as the lithium disilicate restorations. Early zirconia materials were opaque and white and were not recommended for front teeth restorations. However, remarkable progress has been made. There are changes being made in full-zirconia restorations, including the availability of numerous colors of zirconia and the development of more translucencies.

Zirconia restorations are good choices for single unit restorations for the posterior teeth.  

 

Cosmetic Dentistry & Your Smile!

Porcelain-Fused-to Metal (PFM) Crowns are fabricated from both metal and porcelain. Porcelain is fused to an underlying metal substructure to form the overall shape of the crown.

The advantages of PFM Crowns are esthetics, strength and durability. The principal uses are crowns and fixed bridges. Different shades of porcelain can mimic natural tooth appearance.

The disadvantages of PFM Crowns are that they may wear opposing teeth, porcelain on the crown may fracture, dark lines along the crown margin and lifeless appearance.  Dental studies have shown that the porcelain of PFM Crowns can rapidly wear opposing teeth when the porcelain becomes rough; the porcelain surface should be re-glazed or polished adequately after occlusal adjustment. Another disadvantage is that the porcelain portion of PFM Crowns may fracture or separate from its underlying metal substructure. Sometimes, replacement of a new crown may be needed.  One of the esthetic complaints from patients is the dark line at the gingival margin of the crown. This usually occurs when the gum tissues recede and the metal margin of the crown shows. The porcelain that is used to mask the metal substructure gives a lifeless or dull appearance of the crown. This would be an important concern for front teeth crown restorations.

"Porcelain-Fused-to Metal Crowns are good choices for crowns and fixed bridges in the posterior area (molars)," Dr. Anna Lee.

Get The Facts About Crowns

Different Types of Crown (Caps)  

 There are a number of factors that need to be considered when making the decision of restoring the tooth with a crown restoration. In general, there are 3 different types of crown restorations: Metal, Porcelain-Fused-to Metal (PFM) and all Ceramic.

Metal Crowns are fabricated entirely out of metal. There are a number of types of dental alloys; they are high noble metal (precious), noble metal (semiprecious) and non-noble metal (base).

High noble alloys contain 60% noble metal (gold, platinum, and/or palladium), of which over 40% is gold. Noble alloys contain 25% noble metal.  Non-noble alloys contain less than 25% noble metal with the other contents being nickel, chromium or beryllium. Some people are allergic to nickel.

The advantages of metal crowns are strength, longevity, biocompatibility, and good fit.  Metal crowns have high strength and toughness that resist fracture and wear. They provide a good seal against leakages. The high noble metals are the most biocompatible to the gingival tissues.

The disadvantages of metal crowns are esthetics, sensitivity and cost. The metal colors are silver or gold and they do not mimic natural teeth.  Teeth may be sensitive to hot and cold after crown cementation.  Some people reported that they are allergic to non-noble alloy such as nickel. Noble and high noble metals cost more than the non-noble metals.

All metal crowns are good choices for patients with strong bites and those with parafunctional habits, such as grinding or clenching.