Rational of post placement:
Post is indicated in a compromised coronal structure of a tooth. Teeth reinforced with post had 10% complications (Goodacre et al.,2003).
Length of the post:
The longer the post the better the stress distribution. VRF was 2.5% when the post’s length was equal to the length of the crown and 25% when the post’s length was quarter to the length of the crown (Sorensen and Martinoff, 2004) Fig.1.
Greater resistance to failure was found in teeth with long posts 10 mm and long ferrule 2.5 mm (Isidor et al.,1999). Collared core was suggested as 2ndry ferrule but it was found that it sig increased the mean stress (Looney et al.,1999).
At least 4 mm of GP should be left underneath the post to prevent re-infection. The principle of apical seal should override the length of the post if a conflict between these two concepts arise (Mattison et al., 1984) and (Raiden et al.,1994). Post should be cemented as soon as practical to not increase apical leakage (Fox & Gutteridge, 1997).
Posterior teeth lacking cuspal coverage had sig higher failure rate (Sorensen and Martinoff, 2004) Fig.2.
Complete crowns or onlays that cover all cusps are recommended for all posterior pulpless teeth regardless of the amount of remaining coronal tooth structure to reduce the chances of fracture of these teeth.
Overall guidelines of single rooted teeth:
Teeth with compromised coronal structure cast post core is preferred Fig.3.
Types of posts:
Prefabricated post, woven fiber composite post, Zirconia post, and fiber reinforced epoxy resin post