The stiffness and the load to initial fracture of the teeth restored with ParaPost XP posts were higher compared with the fiber-reinforced post groups.

ObjectiveTo study effect of root canal irrigant solutions on the bond strength of cemented fiber posts, and resin cement-tags in root canal dentin.Materials and methodsFifty-two human single-rooted anterior teeth were selected and stored in 1% sodium azide. Crowns were sectioned 2 mm incisal to the cemento enamel junction with diamond bur at high speed under water-cooling. After standard root canal treatment to tested teeth, they were randomly assigned into four groups (n=13) corresponding to the endodontic irrigant solution that was used during post space preparation. The treatment groups were: Group 1: 6.15% sodium hypochlorite; Group 2: 17% EDTA; Group 3: 6.15% NaOCl +17% EDTA; Group 4: 6.15% NaOCl +0.12% chlorhexidine solution. Parallel-sided fiber posts were used for all specimens. Samples were embedded in a cylindrical PVC mounting jig to facilitate perpendicular sectioning. With low speed diamond saw, cervical and apical specimens from each tooth were obtained and subjected to push-out test using universal testing machine. SEM was used to examine the root-canal dentin surface.ResultsStatistical analysis revealed significant difference among the groups at P<0.05. Group 2 treated with EDTA, had the highest bond strength; 18.63±2.85 MPa in cervical specimens and 13.49±3.67 MPa in apical specimens. The cervical specimens of Groups 2 and 3 were significantly different than the apical specimens in the same group. Adhesive failure between cement and dentin was the main failure mode observed in all groups. Groups irrigated with EDTA showed cleaner dentin surface and better resin tag formation, while groups treated with NaOCl showed less resin tag formation and insufficient smear layer removal.ConclusionNaOCl had adverse effect on bond strength of self-adhesive resin cement to radicular dentin. EDTA irrigant solution produced higher bond strength and was more effective in removing smear layer than NaOCl.

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The study aimed to evaluate the effect of graphene oxide (GO) nano-filler content in experimental dental adhesive on its degree of conversion (DC), microtensile bond strength (μTBS) and structural reliability, using Fourier transform infrared spectroscopy (FTIR), Micro-Raman spectroscopy and Scanning electron microscopy (SEM). A resin adhesive was fabricated (control adhesive - CA) and fabricated GO nano-particles were added at 0.5% and 2.0% (m/m) to produce adhesives GOA1 and GOA2 respectively. One hundred and two teeth (specimens) were prepared for dentin exposure and conditioned with 36% phosphoric acid. Specimens in each group (n = 34) were treated with formulated adhesives (CA, GOA1 & GOA2) and photo-polymerized for 20 s followed by composite build up. Sixty specimens were used for μTBS testing in the adhesive groups (CA, GOA1 & GOA2), with half exposed to thermocycling (TC) whereas the remaining half (n = 10) stored in distilled water. Seven specimens each were assessed using SEM and Micro-Raman spectroscopy, in each adhesive group (n = 7). DC for the adhesives was assessed using FTIR. The means of μTBS and DC were analyzed using ANOVA and post hoc Tukey multiple comparisons test. GO nano-filler content showed significant influence on the adhesive μTBS in comparison to controls (p < 0.01). Ageing (TC) revealed significant reduction in the μTBS, except in GOA2 specimens, which showed comparable outcomes among TC and non-TC specimens (p > 0.05). DC was significantly higher in control adhesive [46.8 (3.6)%] compared to GOA2 [37.7 (4.2)%] specimens, however DC was comparable among GOA1 [42.3 (2.9)%] and GOA2 [37.7 (4.2)%] specimens (p > 0.05) respectively. GO exhibited interaction within adhesive and tooth dentin comparable to control adhesive. Increasing GO content showed increase in μTBS of adhesive to dentin, but a decrease in degree of conversion. Under ideal conditions, experimental adhesive with 2% GO content showed acceptable bond strength and DC; and should be further assessed under dynamic conditions to recommend clinical use.

The degree of success in the elimination of bacteria during cavity preparation and prior to the insertion of a restoration may increase the longevity of the restoration and therefore the success of the restorative procedure. The complete eradication of bacteria in a caries-affected tooth, during cavity preparation, is considered a difficult clinical task. In addition to weakening the tooth structure, attempts to excavate extensive carious tissue completely, by only mechanical procedures, may affect the vitality of the pulp. Therefore, disinfection of the cavity preparation after caries excavation can aid in the elimination of bacterial remnants that can be responsible for recurrent caries, postoperative sensitivity, and failure of the restoration. However, the effects of disinfectants on the restorative treatment have been a major concern for dental clinicians and researchers. This review aims to explore existing literature and provide information about different materials and techniques that have been used for disinfecting cavity preparations and their effects and effectiveness in operative dentistry and, therefore, helps dental practitioners with clini cal decision to use cavity disinfectants during restorative procedures. Antimicrobial effectiveness and effects on the pulp and dental restorations, in addition to possible side effects, were all reviewed in this paper.

Aim: The study aimed to assess graphene oxide (GO) adhesive and its dentin interaction using scanning electron microscopy (SEM), MicroRaman spectroscopy and Microtensile bond strength (μTBS). Materials and Methods: Experimental GOA and control adhesives (CA) were fabricated. Presence of GO within the experimental adhesive resin was assessed using SEM and Micro-Raman spectroscopy. Ninety specimens were prepared, sixty teeth were utilized for μTBS, twenty for SEM analysis of interface for CA and GOA and ten were assessed using microRaman spectroscopy. Each specimen was sectioned and exposed dentine was conditioned (35% phosphoric acid) for 10 s. The surface was coated twice with adhesive (15 s) and photopolymerized (20 s). Composite build-up on specimen was photo-polymerized. Among the bonded specimens, thirty specimen were assessed using Micro-Raman spectrometer, SEM and energy dispersive X-ray spectroscopy (EDX), whereas remaining specimens were divided in to three sub-groups ( n = 10) based on the storage of 24 h, 8 weeks and 16 weeks. μTBS testing was performed at a crosshead speed of 0.5 mm/min using a microtensile tester. The means of μ-tbs were analyzed using ANOVA and post hoc Tukey multiple comparisons test. Results: No significant difference in μTBS of CA and GOA was observed. Storage time presented a significant interaction on the μTBS ( p < 0.01). The highest and lowest μTBS was evident in CA (30.47 (3.55)) at 24 h and CA (22.88 (3.61)) at 18 weeks. Micro-Raman analysis identified peaks of 1200 cm-1 to 1800 cm1, D and G bands of GO nanoparticles in the resin. Uniform distribution of graphene oxide nanoparticles was present at the adhesive and hybrid layer. Conclusion: GO showed interaction within adhesive and tooth dentin similar to CA, along with formation of hybrid layer. In ideal conditions (absence of nanoleakage), graphene oxide modified adhesive shows comparable bond strength and durability of resin dentine bond.

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