文档介绍：Margin (Finish line) placement
Finish line of the preparation is the end of tooth preparation.
Finish Line
Studies have supported the use of supra-gingival or equi-gingival finish lines rather than sub-gingival finish line whenever possible to ensure periodontal health
Supra-gingival finish line
v Sub-gingival finish line
Hanaa I. Sallam
Advantages of supra-gingival margins:
Easily prepared
No soft tissue trauma
Easy impression
Easy finishing, easy cleaning
Easy evaluation of the preparation margins at the time of placement and at the call appointments
11-May-18
Rasha Nabil Sami
4
Indications of subgingival margins
Cervical caries , cervical erosions or restorations extending subgingivally.
Proximal contact extended to the gingival crest
Additional retention and /or resistance is needed
For esthetics in anterior region
Root sensitivity
Indications of subgingival margins
1-Cervical caries , erosion, abrasion or restoration.
11-May-18
Hanaa I. Sallam
Proximal contacts extending to the gingival crest.
11-May-18
Hanaa I. Sallam
To increase the occluso-gingival dimension for better retention and resistance .
11-May-18
Hanaa I. Sallam
For esthetics in anterior region
11-May-18
Hanaa I. Sallam
Root sensitivity which cannot be controlled by more conservative procedures (such as application of dentin bonding agents).
11-May-18
Hanaa I. Sallam
When a subgingival finish line is required, it has been suggested that extension to the epithelial attachment be avoided.
The distance from the epithelial attachment to the crest of the alveolar bone has been described as the “Biologic Width”. It is normally about 2mm wide, including the epithelial attachment and the connective tissue attachment.
If the margin of a restoration intrudes into this biologic width inflammation will result and osteoclastic activity is stimulated.