<p>Evaluating Fracture Resistance And Failure Modes Of Root Filled Teeth Restored With CAD/CAM-Fabricated Post And Core</p>

Abstract

ObjectiveThe aim of this study was to measure the fracture resistance and failure modes of root-filled teeth restored with three different computer-aided design/computer-aided manufacturing (CAD/CAM)-fabricated post and core assemblies.MethodsThirty extracted intact maxillary central incisors were used in the study, and the teeth were endodontically treated and sectioned to a root length of 16 mm. The samples were divided into three groups (n = 10) according to the mean of the dimensions at the cervical portion of the root. The posts and cores were fabricated with CAD/CAM technology using metal, zirconia, and polymer-infiltrated ceramic network (PICN) material. The posts were luted using resin cement, and then, metal crowns were fabricated, cemented, and then subjected to a compression to determine the fracture resistance force. Fracture of the post and core or fracture of the root above the level of the acrylic resin was considered as a favorable fracture, while nonfavorable fractures were those where the root fracture occurred below the level of the acrylic resin. Statistical analysis was carried out using SPSS software, and one-way analysis of variance was used to analyze root fracture resistance in Newton. The number of failure modes, post–core fractures and/or root fractures was calculated. The differences between study groups were revealed using the chi-square test.ResultsThe results of ANOVA revealed a nonsignificant difference in the resistance to fracture among the study groups (P = 0.114). The failure modes were nonfavorable for all metal and zirconia samples and seven PICN samples. However, three PICN samples exhibited a favorable represented by core fracture without root fracture.ConclusionThere was no significant difference between metal and zirconia samples in terms of nonfavorable fracture, while few PICN samples exhibited a favorable fracture. PICN material can be used in the fabrication of post and core assemblies using CAD/CAM.

Outcome of teeth restored with CAD/CAM zirconium dioxide post-cores: a retrospective study with a follow-up period of 3–6 years

“…In this study, five cases (two premolars and three molars) exhibited crown collapse during the follow-up period, but no post rupture was observed. The probability of crown collapse was 1.9%, which is a common complication of zirconia all-ceramic crowns, consistent with the rates of porcelain collapse reported in previous studies [ 9 , 28 ]. Regrettably, abnormal occlusal function was not recorded at follow-up and thus was not described in the results.…”

Comparative Analysis of Different Sizes of Prefabricated Metal Posts Placed in Relation to Premolars- A Retrospective Analysis

“…Achieving a post diameter that is strong to support the occlusal loads and does not interfere with the resistance of the remaining tooth structure is one of the major aims in rehabilitation. The comparison of different post thickness (1 and 1.5mm) showed no statistically significant differences in both materials 13 . This results suggests that when restoring anterior endodontically treated teeth, thin post can be indicated.…”

Customized Post and Cores Fabricated with CAD/CAM Technology: A Literature Review

“… 48 Resin-based post and cores have a modulus of elasticity that is closer to dentin, and thus when they fail, the resultant fractures are typically more repairable, compared with those that occur with zirconia. 67 In addition, composite resin-based materials do not require sintering, which allows precise manufacturing of the post and cores and reduces manufacturing time and cost. 60 All reported ceramic- and resin-based materials yielded excellent aesthetic outcomes when teeth were restored with an all-ceramic crown.…”