Porcelain crown cervical margin of the black line on how to avoid

One. Reasons:

1. The edge of the prosthesis is not close together, exposure to the color of the dental hard tissues.

2. Porcelain crowns porcelain layer thickness, revealing the metal color of the inner crown.

3. Ordinary porcelain crowns due to the use of nickel-chromium alloy, 3-5 years after the repair, free of metal elements, so that the local hard and soft tissue coloration.

4. Porcelain crown shoulder, lack of preparation, led to the restoration of oppression gums, gums ischemia, dark color.

5 The edge of the prosthesis preparation is deep enough, although the prosthesis itself, preparation is perfect, but that has been discolored teeth or dental instruments nickel-chromium alloy post core color is exposed through the marginal gingival.

Two. Preventive measures:

1. The extent of damage to the teeth, post and core and Orthodontics to bypass the "myths" to go crown restoration design of different materials, such as the choice of porcelain pile combined with all-ceramic crowns to achieve the best cosmetic results.

2. To ensure adequate thickness of the lip and cheek side of the shoulder part of the ceramic layer.

3. The edge of the porcelain crown should extend to the gingival sulcus 0.5mm, and a smooth migration.

4. Ordinary porcelain crowns can be used with shoulder porcelain, can significantly improve the edge of the black line.

5 According to the specific circumstances and economic conditions of the teeth gum to determine the type of crown, and select the most suitable design.