Direct pulp capping with an adhesive system in management of a complicated incisor fracture: a three-year follow-up case report

Summary Objectives This article describes a direct pulp capping with an adhesive system and an immediate reattachment of the intact fractured tooth fragment after an impact trauma to the maxillary lateral incisor that caused a complicated crown fracture and pulpal exposure. Materials and methods In this case, a simple reattachment technique was performed without additional preparation. A hybridization of the exposed dentin with an adhesive system was chosen to protect the pulp-dentin interface and bonding the tooth fragment as precisely as possible. A resin composite was used to fill the discontinuity between the fragment and the tooth. The clinical procedure can be considered safe and simple. Results and conclusions After three years, the tooth had satisfying esthetics and excellent function and pulp was still vital with no signs or symptoms of inflammation. Clinician should be updated with the current methods and techniques for the management of complicated tooth fracture

Effect of fiber posts on stress distribution of endodontically treated upper premolars : finite element analysis

By means of a finite element method (FEM), the present study evaluated the effect of fiber post (FP) placement on the stress distribution occurring in endodontically treated upper first premolars (UFPs) with mesial–occlusal–distal (MOD) nanohybrid composite restorations under subcritical static load. FEM models were created to simulate four different clinical situations involving endodontically treated UFPs with MOD cavities restored with one of the following: composite resin; composite and one FP in the palatal root; composite and one FP in the buccal root; or composite and two FPs. As control, the model of an intact UFP was included. A simulated load of 150 N was applied. Stress distribution was observed on each model surface, on the mid buccal–palatal plane, and on two horizontal planes (at cervical and root-furcation levels); the maximum Von Mises stress values were calculated. All analyses were replicated three times, using the mechanical parameters from three different nanohybrid resin composite restorative materials. In the presence of FPs, the maximum stress values recorded on dentin (in cervical and root-furcation areas) appeared slightly reduced, compared to the endodontically treated tooth restored with no post; in the same areas, the overall Von Mises maps revealed more favorable stress distributions. FPs in maxillary premolars with MOD cavities can lead to a positive redistribution of potentially dangerous stress concentrations away from the cervical and the root-furcation dentin

In Vitro Microleakage Evaluation of Bioceramic and Zinc-Eugenol Sealers with Two Obturation Techniques

Aim of the study is to compare the quality of the apical seal offered by a zinc-eugenol and a tricalcium-silicate-based sealer, both used with the single-cone or with the continuous wave of condensation technique. Forty central incisors were divided into four groups (n = 10), according to the two sealers and the two obturation techniques under investigation, and their outer surface was isolated with nail varnish. After endodontic treatment, samples were immersed in methylene blue dye for 72 h, then included in self-curing resin and sectioned to longitudinally expose the canal apical third. The depth of dye penetration was measured in each group. Mean values were compared by two-way-ANOVA test. Multiple comparisons were performed by Tukey test. The level of significance was set at 0.05 in all tests. The continuous wave of condensation technique led to reduced microleakage. Moreover, dye penetration values were reduced for the tricalcium-silicate sealer. In terms of microleakage, the warm continuous wave of condensation technique seems promising even when combined to a bioceramic sealer

Effect of Light-Sources and Thicknesses of Composite Onlays on Micro-Hardness of Luting Composites

The aim of this study was to compare three different light-curing-units (LCUs) and determine their effectiveness in the adhesive cementation of indirect composite restorations when a light-curing resin cement is used. Two resin composites were selected: Enamel Plus HRI (Micerium) and AURA (SDI). Three thicknesses (3 mm, 4 mm and 5 mm) were produced and applied as overlays and underlays for each resin composite. A standardized composite layer was placed between underlay and overlay surfaces. Light curing of the resin-based luting composites was attained through the overlay filters using LCUs for different exposure times. All specimens were allocated to experimental groups according to the overlay thickness, curing unit and curing time. Vickers Hardness (VH) notches were carried out on each specimen. Data were statistically evaluated. The curing unit, curing time and overlay thickness were significant factors capable of influencing VH values. The results showed significantly decreased VH values with increasing specimen thickness (p < 0.05). Significant differences in VH values were found amongst the LCUs for the various exposure times (p < 0.05). According to the results, a time of cure shorter than 80 s (with a conventional quartz–tungsten–halogen LCU) or shorter than 40 s (with a high-power light-emitting diode (LED) LCU) is not recommended. The only subgroup achieving clinically acceptable VH values after a short 20 s curing time included the 3 mm-thick overlays made out of the AURA composite, when the high-power LED LCU unit was used (VH 51.0). Composite thickness has an intense effect on polymerization. In clinical practice, light-cured resin cements may result in insufficient polymerization for high thickness and inadequate times. High-intensity curing lights can attain the sufficient polymerization of resin cements through overlays in a significantly shorter time than conventional halogen light

In Vitro Mechanical Properties of a Novel Graphene-Reinforced PMMA-Based Dental Restorative Material

Recent studies suggest that the incorporation of graphene in resin-based dental materials might enhance their mechanical properties and even decrease their degree of contraction during polymerization. The present study aimed at comparing the three-point flexural strength (FS), the compressive strength (CS), and the Vickers hardness (VH) of a CAD/CAM poly-methylmethacrylate (PMMA)-based resin, a recently introduced graphene-reinforced CAD/CAM PMMA-based resin (G-PMMA), and a conventional dental bis-acryl composite resin (BACR). No significant differences (p > 0.05) were detected among the materials in terms of flexural strength. On the other hand, a mean flexural modulus value of 9920.1 MPa was recorded in BACR group, significantly higher compared to the flexural modulus detected for G-PMMA (2670.2 MPa) and for conventional PMMA (2505.3) (p < 0.05). In terms of compressive modulus (MPa) and compressive strength (MPa), BACR was significantly stiffer than PMMA and G-PMMA. Concerning VH measurements, a significantly increased hardness emerged comparing the BACR group (VH 98.19) to both PMMA and G-PMMA groups (VH 34.16 and 34.26, respectively). Based on the finding of the present study, the graphene-reinforced (PMMA)-based polymer herein tested was not superior to the conventional PMMA and seemed not able to be considered as an alternative material for permanent restorations, at least in terms of hardness and mechanical response to compressive stress. More research on the mechanical/biological properties of G-PMMAs (and on graphene as a filler) seems still necessary to better clarify their potential as dental restorative materials

Evaluation of in vitro push-out bond strengths of different post-luting systems after artificial aging

BACKGROUND: The purpose of this study was to evaluate the push-out bond strengths of four commercially available adhesive luting systems (two self-adhesive and two etch-and-rinse systems) after mechanical aging. METHODS: Forty single-rooted anterior teeth were divided into four groups according to the luting cement system used: Cement-One (Group 1); One-Q-adhesive Bond + Axia Core Dual (Group 2); SmartCem\uae 2 (Group 3); and XP Bond\uae + Core-X\u2122 Flow (Group 4). Anatomical Post was cemented in groups 1 and 2, and D.T. Light-Post Illusion was cemented in groups 3 and 4. All samples were subjected to masticatory stress simulation consisting of 300,000 cycles applied with a computer-controlled chewing simulator. Push-out bond strength values (MPa) were calculated at cervical, middle, and apical each level, and the total bond strengths were calculated as the averages of the three levels. Statistical analysis was performed with data analysis software and significance was set at P<0.05. RESULTS: Statistically significant differences in total bond strength were detected between the cements (Group 4: 3.28 MPa, Group 1: 2.77 MPa, Group 2: 2.36 MPa, Group 3: 1.13 MPa; P<0.05). Specifically, Group 1 exhibited a lower bond strength in the apical zone, Group 3 exhibited a higher strength in this zone, and groups 2 and 4 exhibited more homogeneous bonding strengths across the different anatomical zones. CONCLUSIONS: After artificial aging, etch-and-rinse luting systems exhibited more homogeneous bond strengths; nevertheless, Cement-One exhibited a total bond strength second only to Core-X Flow