Fundamentals of fixed prosthodontics shillingburg online dating
Non-metallic posts are easier to remove from teeth if needed than metal posts. These posts can be too strong which can lead to root fracture.Direct use of non-metallic posts in the most common use but they can also be built up in the laboratory. However, they are brittle and have a high modulus which can potentially lead to root fracture. It can be difficult and even impossible to remove a ceramic post.In cases where the post space is not a good match for a prefabricated post, a cast post and core can be custom fabricated for the tooth.A resin pattern is produced by placing a preformed plastic "burnout" post into the post space and a resin material, such as Duralay resin, is used to build up the tooth to the proper dimensions.Both of these systems employ a post that is placed within the root canal of the tooth being restored.Thus the tooth must first be endodontically treated.The role of the post is firstly to retain a core restoration and crown, and secondly to redistribute stresses down onto the root, thereby reducing the risk of coronal fracture. The benefit of placing a post into a root canal is improved retention of the crown.The post does not play any role in reinforcing or supporting the tooth and can in fact make it more likely to fracture at the root. Are there large curvatures which would make post placement difficult? Is the remaining dentine thick enough for post preparation? However there are also disadvantages, during the preparation for the post space there is a risk of perforation, a post can also make a tooth more likely to fracture, it makes future orthograde root canal treatment much more difficult and finally it is very destructive and requires excessive removal of tooth tissue.
Non-metallic posts should not be used if there is insufficient sound tooth tissue.Alternatively, an impression can be taken of the post space and dental arch using a plastic post and a polyvinyl siloxane impression material, and this used to construct a suitable post in the dental laboratory.