Abstract
Abstract Introduction Endodontically treated teeth are more susceptible to root fracture than vital teeth. In order to reduce the risk of fracture, the use of intra-radicular posts and crowns is indicated. However, their own fracture resistance remains unclear. Objective To analyze the behavior of metal-ceramic crown copings cemented to two types of intra-radicular posts under tensile stress. Material and method Sixteen metal-ceramic crown copings cemented with zinc phosphate cement to cast metal posts and cores (group 1, n = 8) or with self-adhesive resin cement to glass-fiber posts rebased with composite resin (group 2, n = 8) were subjected to tensile testing after endodontic treatment and standardized preparation. Failure occurred when the crown coping and/or post-core assembly fractured and/or detached. Result In group 1, after the application of a mean tensile load of 46.83 N, 7 crown copings and metal cores separated as a whole, while in 1 specimen the coping detached from the metal core. In group 2, a mean tensile load of 127.68 N resulted in glass-fiber post fracture, and in 1 case the entire crown-post-core assembly was detached. Tensile strength differed significantly between the two groups (p = 0.0085). Conclusion Our findings suggest that metal-ceramic crown copings cemented with self-adhesive resin cement show strong adhesion to composite resin cores associated with glass-fiber posts, thus providing a safe alternative to the use of cast metal posts and cores.
Highlights
Treated teeth are more susceptible to root fracture than vital teeth
Many professionals who advocate the use of cast metal posts and cores raise the question of how copings for metal-ceramic crowns cemented to glass-fiber posts rebased with composite resin would behave under tensile stress
The purpose of the present study was to evaluate the tensile strength of metal-ceramic crown copings cemented to cast metal posts and cores or to glass-fiber posts rebased with composite resin
Summary
Treated teeth are more susceptible to root fracture than vital teeth. In order to reduce the risk of fracture, the use of intra-radicular posts and crowns is indicated. In group 2, a mean tensile load of 127.68 N resulted in glass-fiber post fracture, and in 1 case the entire crown-post-core assembly was detached. Several studies have compared the two post systems with respect to their ability to reduce the risk of root fracture and have described the best techniques and protocols for use of posts, including post length and diameter and adhesive system These studies have used different methods, such as application of oblique load and cyclic load, but all results converge positively to the same conclusion: the use of glass-fiber posts reduces the risk of root fracture, increasing the success of restoration[5,7,9,10,11,12,13,14]. Many professionals who advocate the use of cast metal posts and cores raise the question of how copings for metal-ceramic crowns cemented to glass-fiber posts rebased with composite resin would behave under tensile stress
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