Influence of single post, oval, and multi-post restorative techniques and amount of residual tooth substance on fracture strength of endodontically treated maxillary premolars

Abstract

The aim of this study was to compare the influence of the number of coronal walls and post-endodontic restorations on the mechanical strength of 165 recently extracted endodontically treated maxillary premolars. Methods: The teeth were divided into 3 control (no post) and 3 test groups according to the number of residual walls. Each test group was divided into subgroups according to the type of post-endodontic restoration (single, oval, and multi-post techniques). Samples were prepared conforming to the assigned subgroup. A universal loading machine applied a load parallel to the longitudinal axis of the teeth, thus simulating physiological occlusion. ANOVA and the Kruskal Wallis test were used for comparisons (P ≤ 0.05), and Tukey's test for multiple comparisons. Results: For intact teeth, significant differences were found among all 3 subgroups, with single post showing the highest values. For 3 residual walls, oval post resulted in significantly lower values than single and multi-post systems. For 2 residual walls, the multi-post technique showed almost twice the resistance of oval post restorations. Conclusion: In oval canals the use of a single or multi-post technique increased post-and-core resistance even in intact teeth, whereas oval fiber posts showed no improvements. Multi-post design improved fracture resistance mostly in maxillary premolars lacking both marginal ridges.

Influence of Methodological Variables on Fracture Strength Tests Results of Premolars with Different Number of Residual Walls. A Systematic Review with Meta-Analysis

“…Out of 17 subgroups, the load inclination applied was 90° for nine [ 10 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ] and 30°/45° for eight [ 19 , 20 , 21 , 22 , 23 , 24 ]. PDL simulation was performed in five subgroups [ 10 , 12 , 15 , 22 , 25 ] while thermocycling was applied in five [ 10 , 12 , 15 , 23 , 26 ].…”

“…Out of 17 subgroups, the load inclination applied was 90° for nine [ 10 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ] and 30°/45° for eight [ 19 , 20 , 21 , 22 , 23 , 24 ]. PDL simulation was performed in five subgroups [ 10 , 12 , 15 , 22 , 25 ] while thermocycling was applied in five [ 10 , 12 , 15 , 23 , 26 ]. Tip diameter was respectively lower than 2 mm and between 2 and 3 mm in one group, between 3 and 5 mm in four groups, 6 mm in seven groups and 8 mm in two groups.…”

“…Out of 45 subgroups, the load inclination applied was 90° for twenty-four [ 10 , 12 , 22 , 30 , 31 , 32 , 33 , 34 ] and 30°/45° for twenty-one [ 10 , 13 , 15 , 19 , 23 , 28 , 35 , 36 ]. PDL simulation was performed in twelve subgroups [ 10 , 15 , 22 , 30 , 31 ] while thermocycling was applied in six [ 10 , 30 , 31 ]. Tip diameter was respectively 3 mm in three groups and 6 in seven.…”

Fracture resistance of thin wall endodontically treated teeth without ferrules restored with various techniques

“…Therefore, some studies supported the utilizing of accessory or a multiple fiber post technique to increase the fracture resistance of severe tooth structure loss or wide canal endodontically treated teeth. 8,16,17 The resin composite core materials have also been recommended for luting endodontic posts, especially in a flared canal due to their high strength, simplicity, and homogeneity of using the same material for the post and core placement. It was reported that resin composite core materials combined with an adhesive system is a comparable, and in some ways superior, method for luting endodontic posts compared to the resin cement.…”

“…A thick layer of the resin cement induces air bubbles, shrinkage stresses, and predisposes the post to debonding. Therefore, some studies supported the utilizing of accessory or a multiple fiber post technique to increase the fracture resistance of severe tooth structure loss or wide canal endodontically treated teeth 8,16,17 . The resin composite core materials have also been recommended for luting endodontic posts, especially in a flared canal due to their high strength, simplicity, and homogeneity of using the same material for the post and core placement.…”