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Ceramics: Rationale for Material Selection

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16/07/2012 at 5:32 pm #15733
DrAnilDrAnil
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 Figure 1  Image of the prepared tooth. Significant dentin is exposed. The proposed length flexure and tensile stress risk is at least medium and the restoration thickness would be at least 0.9 mm. This was noted in the chart.

Figure 1

 

Figure 2  Image demonstrating excessive enamel crazing, leakage, and staining. Flexure, tensile, and shear risks would be medium to high. The substrate would depend on preparation.

Figure 2

 

Figure 3  Image demonstrating a deep overbite in which shear and tensile stresses would be at least medium. Bonded porcelain would require maintenance of enamel and an occlusal strategy to reduce leverage on the teeth.

Figure 3

 

Figure 4  Image of a preparation with a poor substrate and subgingival margins where maintaining the seal would be difficult. High-strength ceramics or metal-ceramics would be indicated.

Figure 4

 

Figure 5  Image of minimal preparations prior to application of the bonded porcelain.

Figure 5

 

Figure 6  Two-year postoperative image of very conservative Category 1 bonded porcelain restorations.

Figure 6

 

Figure 7  Preoperative photograph of an inlay in tooth No. 18 and an onlay on tooth No. 19.

Figure 7

 

Figure 8  Postoperative photograph showing a non-layer material in use.

Figure 8

 

Figure 9  Preoperative photograph of a case requiring significant lengthening. There is at least medium risk of flexure and unfavorable stress, and some of the substrate would be dentin. Thus, Category 1 materials were eliminated as a choice.

Figure 9

 

Figure 10  Postoperative photograph after Category 2 materials were applied, with minimal porcelain layering in the incisal one third.

Figure 10

Figure 11  Preoperative photograph of a case in which the patient refused surgery and orthodontics. The treatment goal was to do minimal preparation and use a tough material due to the general medium-to-high risk in every area; obtaining a seal was possible.

Figure 11

 

Figure 12  Postoperative photograph with bonded full-contour restorations in place on the posterior teeth and incisally layered anterior teeth.

Figure 12

 

Figure 13  Preoperative photograph of an old, unesthetic PFM.

Figure 13

Figure 14  Postoperative photograph of a high-alumina crown system.

Figure 14

 

Figure 15  Preoperative photograph of an old PFM. The patient was unhappy with the opacity and metal display at the margin. Category 3 or 4 material is required for this case.

Figure 15

 

Figure 16  Postoperative view.

Figure 16

 

Figure 17  Postoperative photograph of teeth Nos. 18 to 20 in a case with subgingival margins. Photograph courtesy of Yi-Yuan Chang.

Figure 17