Evolution of post and core systems

Comparative Study on Fracture Resistance of Endodontically Treated Tooth in Relation to Variable Ferrule Heights Using Custom-made and Prefabricated Post and Core: An In Vitro Study

Introduction:

Endodontically treated teeth have significantly differentphysical properties compared to vital teeth. To ensure functional longevity,endodontically treated teeth must have at least 5 mm of tooth structure coronalto the crestal bone, 2 mm of coronal tooth structure incisal to the preparationfinish line are necessary to ensure functional integrity.

Aim and Objectives:

To evaluate fracture resistance of endodontically treated teeth restored withcustom cast post, custom cast post with variable ferrule height and teethwithout ferrule, prefabricated post with variable ferrule height and teethwithout ferrule. To compare fracture resistance of teeth restored with customcast post and prefabricated post with variable ferrule heights.

Materials and Methods:

Methodology includes selection of teeth, root canal preparation,post space preparation, grouping of samples, Group A–custom cast post andcore with sub groups of variable ferrule height, pattern fabrication, Group A- pattern fabrication for customized cast post. Group B–pattern fabricationfor prefabricated post and core, investing and casting, cementation, custommade acrylic jig preparation, testing of specimens.

Results:

The differencein the fracture load between the samples of Group A was highly significantat the 0.001 level. Subgroup A4 had highest fracture resistance while GroupA, possessed the least fracture resistance. Subgroups A2, A3 had fractureresistance value intermediate between A1, A4.

Conclusion:

Increasing theferrule height significantly increases (P < 0.001) the fracture resistance ofendodontically treated teeth restored with both custom made cast post andcore and prefabricated post with metal core. Comparatively the custom madecast post and core with variable ferrule height, especially 2 mm ferrule showedsignificant fracture resistance than prefabricated post with metal core. Thepresence of 2 mm ferrule height significantly increases (P < 0.001).

Restoration of an intruded maxillary central incisor with a uniquely designed dowel and core restoration: a case report

This article describes the restoration of an intruded root using a custom-made metal dowel and metal-ceramic veneer core restoration. The treatment plan for this patient consisted of restoring the missing esthetics and eliminating psychological trauma by utilizing the root of the intruded maxillary left central incisor to replace both missing central incisor crowns. This treatment will preserve space and bone until the patient is old enough for another prosthodontic restoration to be considered.

CLINICAL SIGNIFICANCE

As the lost fragments were not recovered, we considered this restoration of the intruded root to be the best therapeutic option, considering the effect on the patient's psyche. The patient was satisfied with the final result.

Fabrication of direct fiber-reinforced posts: a structural design concept

As the clinician continues the quest for optimal functional and esthetic success of a tooth-restorative complex, the current selection of restorative materials and techniques may prove overwhelming. Although no single system provides the ideal restorative solution for every clinical circumstance, understanding of general design criteria and the components for the various post and core systems available allow the clinician to appropriately select the method and materials compatible with the existing tooth structure and desired result. This article provides a discussion of the various post and core systems, the methods and materials inherent in these systems, and general design principles. Using that basic information and clinical experience, the authors offer an alternative procedure for the rehabilitation of the intraradicular anatomy of the post-endodontic channel with a direct composite resin--the fiber-reinforced post and core system.

CLINICAL SIGNIFICANCE

Using improved restorative materials that stimulate the physical properties and other characteristics of natural teeth in combination with the proper design principles, the clinician can develop a tooth-restorative complex with optimal functional and esthetic results.

In vitro fatigue resistance of glass ionomer cements used in post-and-core applications

STATEMENT OF PROBLEM

New glass ionomer cements exhibit better mechanical properties than their older counterparts. However, there is concern about their use as a core material in post-and-core applications.

PURPOSE

This in vitro study evaluated the fatigue resistance of 2 new glass ionomer cements, Shofu Hi-Dense and Fuji IX GP, and compared their mechanical behavior as a core material under masticatory load with a silver-reinforced glass ionomer (ESPE Ketac-Silver) and a silver amalgam (Cavex Avaloy LC).

MATERIAL AND METHODS

A total of 100 commercial plastic teeth were divided into 4 groups of 25 specimens each. Titanium posts were placed in the prepared root canals, and cores were built up in amalgam, silver-reinforced glass ionomer cement, and the 2 new glass ionomer cements. The post-and-core specimens were prepared for full cast metal crowns, which were fabricated and cemented with glass ionomer cement. Twenty specimens from each group were placed in a mastication simulator and cyclically loaded with a 400 N force for 1.5 million cycles. The 5 remaining specimens were used as controls. The specimens were sectioned and observed macroscopically and microscopically to determine the number of defects (alterations) in each material. Observed defects were verified with the Kruskal-Wallis test, and the 4 core materials were ranked with the Tukey multiple comparisons test.

RESULTS

The mean rank sum values of the defects were as follows: Cavex Avaloy LC Amalgam (16.75), Fuji IX GP (38.50), Shofu Hi-Dense (39.53), and ESPE Ketac-Silver (67.22). The amalgam alloy was significantly different (P< .05) from the others.

CONCLUSION

Under the conditions of this study, the 2 new glass ionomer cements used as core materials showed a higher number of defects than amalgam. These results suggest that their fatigue resistance may be inadequate for post-and-core applications.

Foundation restorations in fixed prosthodontics: current knowledge and future needs

PURPOSE

The Ad Hoc Committee on Research in Fixed Prosthodontics established by the Academy of Fixed Prosthodontics publishes a yearly comprehensive literature review on a selected topic. The subject for this year is foundation restorations.

METHODS

Literature of various in vitro and in vivo investigations that included technical and clinical articles was reviewed to provide clinical guidelines for the dentist when selecting methods and materials for restoration of structurally compromised teeth. Topics discussed and critically reviewed include: (1) desirable features of foundation restorations, (2) foundations for pulpless teeth, (3) historic perspectives, (4) cast posts and cores, (5) role of the ferrule effect, (6) prefabricated posts, (7) direct cores, (8) foundation restorations for severely compromised teeth, (9) problems and limitations, (10) future needs, and (11) directions for future research.

CONCLUSION

This comprehensive review brings together literature from a variety of in vitro and in vivo studies, along with technique articles and clinical reports to provide meaningful guidelines for the dentist when selecting methods and materials for the restoration of structurally compromised teeth.

Direct core buildup using a preformed crown and prefabricated zirconium oxide post

This article describes a procedure that can produce a post and core in a reasonable chair time during a single session. With a preformed crown for core buildup, and being relatively rapid, this is a fairly simple procedure that has good results.

Esthetic considerations in restoring endodontically treated teeth with posts and cores

Posts and cores are often required for the restoration of endodontically treated teeth. Many methods for making post-and-core reconstructions have been described. With the increased use of all-ceramic systems for esthetic tooth restorations, there is a need for esthetic core reconstructions. This article describes several methods for fabricating esthetic posts and cores.