Evaluation of the effect of calcium hydroxide and endodontic irrigants on the push-out bond strength of fiber post - an in vitro study

Abstract

BackgroundIn recent years, fibre-reinforced composite posts have been proposed for the restoration of root filled teeth as an alternative to pre-fabricated posts or metal dowels.Aims and objectivesThe aim of the study was to analyze the effect of endodontic irrigants used for removal of calcium hydroxide on the push-out bond strength of fiber posts to root canal dentin.MethodsForty human permanent single-rooted mandibular premolars with relatively straight roots were taken and access cavities were prepared and biomechanical preparation done using Rotar Y protaper file till size F2. The samples were divided into Experimental group and Control group. In Experimental groups Intracanal dressing of calcium hydroxide was removed by 2.5% NaOCl and 17% EDTA (Group1), MTAD (Group II) and Qmix (Group III). Control group did not receive Intracanal calcium hydroxide dressing. Canals were obturated using size F2 protaper gutta-percha points and AH plus sealer. After storage for 24 hours, post space was prepared. Forty Tenax fiber post (Coltene) were cemented with Rely X U200 resin. The roots were then transversally sectioned into 3 slices of 1mm thickness corresponding to cervical, middle and apical third. The slices obtained were subjected to micro-push-out bond strength test using a universal testing machine. The data obtained was subjected to statistical analysis using One-Way ANOVA test. P value of .05 was considered as statistically significant level.ResultsThe mean push-out bond strength values for controls, NaOCl/EDTA, MTAD and QMIX group at cervical third were 10.17, 15.84, 20.39 and 20.98 whereas at apical third 4.78, 8.85, 11.66 and 12.10.ConclusionQmix showed higher push-out bond strength values followed by MTAD and NaOCl/EDTA. All the groups showed lowest push-out bond strength values in the apical third followed by middle and the maximum in the cervical region.

Comparison of the effect of QMix and conventional root canal irrigants on push‐out bond strength of fiber post to root dentin

“…They explained that this finding might be attributed to effective elimination of the smear layer by QMix (Gündoğar et al, 2018). Assessing the effect of different irrigating solutions, used for elimination of calcium hydroxide from the root canal system, on the bond strength of fiber‐reinforced composite posts revealed maximum bond strength in the QMix group, followed by MTAD and NaOCl/EDTA groups (Chaudhary et al, 2018). In 2013, Elnaghy et al evaluated the effect of QMix on bond strength of glass fiber posts to root dentin.…”

The effects of root canal perforation repair materials on the bond strength of fiber posts

“…13 In fact, studies have shown that calcium hydroxide cannot be completely removed from root canals with any of a wide range of commonly used devices or techniques, [14][15][16][17] and it has been suggested that residual calcium hydroxide may reduce the bond strength of fiber posts subsequently applied to root canals. [18][19][20] Ceramics are inorganic, non-metallic materials formed by subjecting raw minerals to high temperatures. 21 Bioceramics refer to both biocompatible ceramic materials and metal oxides that possess good sealing, antibacterial and antifungal characteristics, and are used in medicine and dentistry 22 for their ability to mimic or induce tissue regeneration.…”

“…33 In addition to intracanal medicaments that change the structure of rootcanal dentin, bonding at dentin-cement-post interfaces can also be affected by root-canal irrigation solutions, filling materials, and bioceramics as well as by the preparation of the post space and the presence/thickness of a smear layer. 20 Perforation repair materials and their interactions with residual calcium hydroxide used as an intercanal medicament may affect the bond strength of prefabricated fiber posts. This in vitro study compared the effects of four different root-repair materials (MTA, Biodentine, BioAggregate, EndoSequence BC) with and without calcium hydroxide on the bond strength of fiber posts.…”

“…13 In fact, studies have shown that calcium hydroxide cannot be completely removed from root canals with any of a wide range of commonly used devices or techniques, 14–17 and it has been suggested that residual calcium hydroxide may reduce the bond strength of fiber posts subsequently applied to root canals. 18–20…”

“…26 Fiber posts, which have an elastic modulus lower than metal and higher than dentin, have been observed to result in a better distribution of stress 26,27 and have been recommended as an alternative to prefabricated and metal posts for restoring teeth that have had previous root-canal treatment 28 and possess insufficient remaining crown structure to provide adequate core retention. 20 The reduction in stresses transmitted to the root canal walls as a result of the relative similarity between the elasticity modulus of fiber posts and that of dentin reduces the risk of vertical fractures. 29 Regardless of post material, stress concentrations are reported to occur mainly at the apical and cervical regions of the tooth, although flexible posts result in stress concentrations in dentin, whereas rigid posts result in stress concentrations at the interfaces between dentin, cement, and post.…”