Retrospective clinical evaluation of a no-prep porcelain veneer protocol.

STATEMENT OF PROBLEM: Porcelain laminate veneers without tooth preparation (no-prep veneers) might represent a convenient and conservative option for the esthetic rehabilitation of anterior teeth. However, controversy exists about their predictability. PURPOSE: The purpose of this clinical study was to retrospectively evaluate the performance of no-prep porcelain veneers placed as per the recently proposed "CH no-prep" protocol, which claimed to overcome many of the drawbacks of previous no-prep veneer solutions. MATERIAL AND METHODS: One hundred eight no-prep porcelain laminate veneers based on the CH no-prep protocol were placed in 21 patients between 2015 and 2017. All participants were contacted, and 15 received a recall examination: a total of 78 veneers were evaluated as per the Clinical-Photographic-Micromorphologic coding. Plaque and gingival indexes and any increase in gingival recession were recorded. Pulp vitality was verified. A survival rate based on the count of absolute failures and a success rate summarizing the effect of both absolute and relative failures were calculated. RESULTS: The mean observation period was 43.1 months, with an observation interval of 36 to 60 months and a survival rate of 97.4%. From the 5 relative failures (3 minimal fractures or chips and 2 limited marginal discolorations) and the 2 absolute failures (unrepairable fractures), an overall success rate of 91.0% was recorded, with 71 restorations that were judged excellent in terms of clinical acceptance after the recall examination. From the Clinical-Photographic-Micromorphologic evaluation, 5 restorations (6.4%) showed minimal issues for marginal integrity, while a limited porcelain overhang was identified on 2 restorations (2.8%). Micromorphologic analyses confirmed the clinical evaluations. No periodontal recession was observed, and plaque and gingival indexes appeared stable. CONCLUSIONS: Porcelain laminate veneers placed as per the CH no-prep protocol demonstrated excellent performances after 36 to 60 months of clinical service. The achieved outcomes, in terms of color match and overall esthetic and anatomic integration, confirmed that a prepless approach may be safely adopted provided that strict rules for patient selection and finish line placement are adopted.

Meta-analytical analysis on components released from resin-based dental materials.

OBJECTIVES: Resin-based materials are applied in every branch of dentistry. Due to their tendency to release substances in the oral environment, doubts have been raised about their actual safety. This review aims to provide a comprehensive analysis of the last decade literature regarding the concentrations of elutable substances released from dental resin-based materials in different type of solvents. MATERIALS AND METHODS: All the literature published on dental journals between January 2010 and April 2022 was searched using international databases (PubMed, Scopus, Web of Science). Due to strict inclusion criteria, only 23 papers out of 877 were considered eligible. The concentration of eluted substances related to surface and volume of the sample was analyzed, considering data at 24 h as a reference. The total cumulative release was examined as well. RESULTS: The most eluted substances were HEMA, TEGDMA, and BPA, while the less eluted were Bis-GMA and UDMA. Organic solvents caused significantly higher release of substances than water-based ones. A statistically significant inverse correlation between the release of molecules and their molecular mass was observed. A statistically significant positive correlation between the amount of released molecule and the specimen surface area was detected, as well as a weak positive correlation between the release and the specimen volume. CONCLUSIONS: Type of solvent, molecular mass of eluates, and specimen surface and volume affect substances release from materials. CLINICAL RELEVANCE: It could be advisable to rely on materials based on monomers with a reduced elution tendency for clinical procedures.

Shear bond strength of glass ionomer and resin-based cements to different types of zirconia.

OBJECTIVE: To investigate the shear bond strength (SBS) of a glass ionomer (GI) cement, an 10-methacryloyloxy-decyl dihydrogen phosphate (MDP)-based adhesive resin cement (MDP-based AC), an MDP-based self-adhesive resin cement (MDP-based SAC), an MDP-free self-adhesive resin cement (MDP-free SAC), and a resin-modified GI (RMGI) cement to a 3 mol% yttria-stabilized (3Y-TZP) and a 5 mol% yttria partially stabilized zirconia (5Y-PSZ). MATERIALS AND METHODS: Fifty blocks were produced using 3Y-TZP and 5Y-PSZ, assigned to subgroups based on the five cements investigated (n = 10) and luted to cylindrical specimens of the same substrate. Each specimen was loaded in a SBS apparatus to failure. Mean SBS (MPa) values and standard deviations were calculated. Data were analyzed using a two-way analysis of variance and Tukey tests (α = .05). Failed specimens were subjected to fractographic analysis. RESULTS: MDP-based AC and MDP-based SAC cements displayed the highest SBS values with both the substrates; GI cement showed the lowest. RMGI and MDP-free SAC cements performed better with 3Y-TZP than with 5Y-PSZ. Fractographic analysis revealed only adhesive and mixed failures. CONCLUSIONS: MDP-based AC and MDP-based SAC cements are suitable for both 3Y-TZP and 5Y-PSZ. MDP-free SAC and RMGI cements are adequate choices for 3Y-TZP, but seem less effective with 5Y-PSZ. CLINICAL SIGNIFICANCE: MDP-based SACs appear to be as reliable as MDP-based ACs for both 3Y-TZP and 5Y-PSZ cementation. Specifically, for 5Y-PSZ cementation, resin-based MDP-free SACs do not seem to guarantee predictable results in terms of SBS.

Protocol for a new concept of no-prep ultrathin ceramic veneers.

OBJECTIVES: No-prep veneers, although ideally considered the best option because of tooth structure maximum preservation, have been frequently criticized for some potential limitations including esthetic outcomes and periodontal complications. CLINICAL CONSIDERATIONS: A new protocol to optimize no-prep veneers restorations is presented. A key point of the proposed technique is to identify optimal margins' positions: margin is positioned in the point of maximum convexity of teeth, avoiding the over contouring of traditional no-prep veneers. CONCLUSION: The procedure can be appreciated for the marginal accuracy and the resulting aesthetic stability. The case reports show that properly managed no-prep veneers can have biologically healthy and aesthetically pleasant tooth-restoration transitions and emergence profiles. CLINICAL SIGNIFICANCE: High-quality no-prep veneers can be more challenging to realize than conventional veneers and the success seems to depend on a combination of good case selection, margins' position, sound adhesive principles, clinical, and laboratory experience.

No-Prep Rehabilitation of Fractured Maxillary Incisors with Partial Veneers.

OBJECTIVE: Therapeutic options for dental trauma depend on the injuries' features. For patients with uncomplicated tooth fractures, adhesive materials and composite partial veneers may be a therapeutic solution that completely preserves healthy tooth structure. CLINICAL CONSIDERATIONS: An ultra-conservative approach, using indirect composite partial veneers to restore fractured anterior teeth is described in these case reports. CONCLUSION: Despite the position of the finish line in the middle of the clinical crown, this solution offers functional and esthetic outcomes using an indirect composite technique, and appears to be a suitable alternative to direct composite restorations or less conservative indirect veneers. CLINICAL SIGNIFICANCE: Indirect composite partial veneers present considerable advantages, such as ultra-minimally invasive properties and excellent esthetic appearances. The success seems to depend on a combination of sound adhesive principles, adequate design of the restoration, laboratory experience, and cementation techniques. (J Esthet Restor Dent 28:351-358, 2016).

Five-year retrospective clinical study of indirect composite restorations luted with a light-cured composite in posterior teeth.

OBJECTIVES: The purpose of this study was to evaluate the clinical performance of indirect composite onlays-overlays bonded with a light-cured composite on vital molars. MATERIALS AND METHODS: Forty-one patients were restored with 79 indirect composite restorations. The restorations were studied for an observation time of 5 years. Marginal adaptation, marginal discolouration, secondary caries, colour match and anatomic form were clinically examined following modified United States Public Health Service criteria. Each restoration was also examined for fractures and debonding. Endodontic complications were registered. Survival rate, based just on failures that required a replacement, and success rate that included also failures that required a repair intervention were statistically determined using a restoration and a patient-related analysis. RESULTS: After 5 years, using each restoration as a statistical unit, the survival rate was 91.1% and the success rate 84.8%, with a high Kaplan-Meier estimated success probability of 0.852. Using the patient as the statistical unit, the survival rate was 90.2% and the success rate 85.4%, corresponding to a Kaplan-Meier estimated success probability of 0.857. On the basis of the criteria used, most of the restorations rated Alpha. Regarding marginal adaptation and marginal discolouration, 5 and 10.1% of the restorations, respectively, revealed Bravo ratings CONCLUSIONS: Indirect composite restorations offer a predictable and successful treatment modality giving an optimal preservation of sound tooth tissue. CLINICAL RELEVANCE: The preparation, cementation and finishing procedures are considered key factors for the long-term success of the indirect composite restorations.

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.

In Vitro Evaluation of Candida albicans Adhesion on Heat-Cured Resin-Based Dental Composites.

Microbial adhesion on dental restorative materials may jeopardize the restorative treatment long-term outcome. The goal of this in vitro study was to assess Candida albicans capability to adhere and form a biofilm on the surface of heat-cured dental composites having different formulations but subjected to identical surface treatments and polymerization protocols. Three commercially available composites were evaluated: GrandioSO (GR), Venus Diamond (VD) and Enamel Plus HRi Biofunction (BF). Cylindrical specimens were prepared for quantitative determination of C. albicans S5 planktonic CFU count, sessile cells CFU count and biomass optical density (OD570 nm). Qualitative Concanavalin-A assays (for extracellular polymeric substances of a biofilm matrix) and Scanning Electron Microscope (SEM) analyses (for the morphology of sessile colonies) were also performed. Focusing on planktonic CFU count, a slight but not significant reduction was observed with VD as compared to GR. Regarding sessile cells CFU count and biomass OD570 nm, a significant increase was observed for VD compared to GR and BF. Concanavalin-A assays and SEM analyses confirmed the quantitative results. Different formulations of commercially available resin composites may differently interact with C. albicans. The present results showed a relatively more pronounced antiadhesive effect for BF and GR, with a reduction in sessile cells CFU count and biomass quantification.

Influence of curing time, overlay material and thickness on three light-curing composites used for luting indirect composite restorations.

PURPOSE: To assess the microhardness of three resin composites employed in the adhesive luting of indirect composite restorations and examine the influence of the overlay material and thickness as well as the curing time on polymerization rate. MATERIALS AND METHODS: Three commercially available resin composites were selected: Enamel Plus HRI (Micerium) (ENA), Saremco ELS (Saremco Dental) (SAR), Esthet-X HD (Dentsply/DeTrey) (EST-X). Post-polymerized cylinders of 6 different thicknesses were produced and used as overlays: 2 mm, 3 mm, 3.5 mm, 4 mm, 5 mm, and 6 mm. Two-mm-thick disks were produced and employed as underlays. A standardized amount of composite paste was placed between the underlay and the overlay surfaces which were maintained at a fixed distance of 0.5 mm. Light curing of the luting composite layer was performed through the overlays for 40, 80, or 120 s. For each specimen, the composite to be cured, the cured overlay, and the underlay were made out of the same batch of resin composite. All specimens were assigned to three experimental groups on the basis of the resin composite used, and to subgroups on the basis of the overlay thickness and the curing time, resulting in 54 experimental subgroups (n = 5). Forty-five additional specimens, 15 for each material under investigation, were produced and subjected to 40, 80, or 120 s of light curing using a microscope glass as an overlay; they were assigned to 9 control subgroups (n = 5). Three Vicker's hardness (VH) indentations were performed on each specimen. Means and standard deviations were calculated. Data were statistically analyzed using 3-way ANOVA. Within the same material, VH values lower than 55% of control were not considered acceptable. RESULTS: The used material, the overlay thickness, and the curing time significantly influenced VH values. In the ENA group, acceptable hardness values were achieved with 3.5-mm or thinner overlays after 120 or 80 s curing time (VH 41.75 and 39.32, respectively), and with 2-mm overlays after 40 s (VH 54.13). In the SAR group, acceptable hardness values were only achieved with 2-mm-thick overlays after 120 or 80 s curing time (VH 39.81 and 29.78, respectively). In the EST-X group, acceptable hardness values were only achieved with 3-mm or thinner overlays, after 120 or 80 s curing time (VH 36.20 and 36.03, respectively). CONCLUSION: Curing time, restoration thickness, and overlay material significantly influenced the microhardness of the tested resin composites employed as luting agents. The clinician should carefully keep these factors under control.

Clinical evaluation on porcelain laminate veneers bonded with light-cured composite: results up to 7 years.

The purpose of this study was to evaluate the clinical performance of laminate porcelain veneers bonded with a light-cured composite. Thirty patients were restored with 119 porcelain laminate veneers. The veneers were studied for an observation time of 7 years. Marginal adaptation, marginal discoloration, secondary caries, color match, and anatomic form were clinically examined following modified United States Public Health Service (USPHS) criteria. Each restoration was also examined for cracks, fractures, and debonding. Pulp vitality was verified. In addition, plaque and gingival indexes and increase in gingival recession were recorded. Survival rate evaluating absolute failures and success rate describing relative failures were statistically determined, using both restoration and patient-related analyses. On the basis of the criteria used, most of the veneers rated Alfa. After 7 years, the results of the clinical investigation regarding marginal adaptation and marginal discoloration revealed only 2.5% and 4.2% Bravo ratings, respectively, among the 119 initially placed veneers. Using the restoration as the statistical unit, the survival rate was 97.5%, with a high estimated success probability of 0.843 after 7 years. Using the patient as the statistical unit, the survival rate was 90.0% and the estimated success probability after 7 years was 0.824. Gingival response to the veneers was all in the satisfactory range. Porcelain laminate veneers offer a predictable and successful treatment modality giving a maximum preservation of sound tooth. The preparation, cementation, and finishing procedures adopted are considered key factors for the long-term success and aesthetical result of the veneer restorations.

Safe and Ultraconservative Rehabilitation of Worn Teeth Patients: How Sectional Clear Aligners May Enhance the Prosthetic Treatment Plan.

This study describes the clinical workflow for occlusal vertical dimension (OVD) increase in patients showing extensive tooth wear and mild teeth misalignment/crowding. A patient affected by dental erosion and occlusal abnormalities was treated to improve her situation. After ascertaining sound condyle and temporomandibular joint (TMJ) conditions, an OVD increase was sought to provide enough inter-occlusal space for the restorations. The use of TMJ three-dimensional imaging throughout the clinical procedures allowed to objectively track the condyle and disk position and confirm a steady condyle-glenoid cavity relationship before definitive restorations placement. Sectional clear aligner therapy prior to totally additive prosthetic rehabilitation allowed obtaining slight derotation and movements of anterior teeth, thus maximizing sound tissue preservation. Adhesively luted restorations were finally delivered on both anterior and posterior sectors. At the end of the treatment, the pre-operative TMJ balance appeared successfully preserved, and the patient was satisfied with the aesthetic and function achieved.

The Effect of Dentin Bonding and Material Thickness on the Flexural Properties of a Lithium-Disilicate Glass-Ceramic.

PURPOSE: Thanks to adhesive techniques and strengthened glass ceramics, ultrathin bonded occlusal veneers have been recently introduced. However, since a universally accepted thickness limit for ultrathin ceramics has yet to be established, their resistance to fracture needs to be better investigated. The purpose of this in vitro study was to evaluate the effect of dentin bonding on the flexural properties (ie, fracture load and flexural strength) of a lithium-disilicate (LD) glass ceramic when used in thicknesses equal to or less than the manufacturer's recommendations for occlusal restorations. MATERIALS AND METHODS: A total of 96 dentin slices (2.0 mm thick and 15 mm long) were obtained by sectioning bovine teeth along their long axes. LD slices of different thicknesses (1.5 mm/1.3 mm/1.0 mm/0.8 mm/0.6 mm) and 15 mm in length were cut from CAD/CAM LD blocks (IPS e.max CAD-C16). In each of 5 experimental groups, 16 dentin slices were adhesively luted to 16 LD slices (n = 16) of the same thickness, in order to create 16 bi-layered dentin-LD bonded assemblies. In the control group, the 16 remaining dentin slices were conventionally cemented to 1.5-mm-thick LD slices (n = 16) using a resin-modified glass-ionomer cement (FujiCEM 2). All dentin-LD assemblies were cut perpendicularly to their joint interface, in order to obtain 1-mm-wide, 15-mm-long bi-layered prismatic beams, having the following final thicknesses: for the 5 experimental groups, 2 mm (dentin layer) + 1.5 mm/ 1.3 mm/1.0 mm/0.8 mm/0.6 mm (LD layer); for the control group, 2 mm (dentin layer) + 1.5 mm (LD layer). All prismatic beams were subjected to a three-point bending test (14-mm span, load applied on the LD side). Fracture loads (N) and flexural strengths (MPa) were recorded. Data were analyzed using one-way ANOVA on ranks tests (α = 0.05). The correlations between the recorded flexural strengths and the dentin:LD thickness ratio and between the flexural strength and the luting strategy were also investigated. The failure modes were observed and classified. RESULTS: No statistically significant differences were recorded between the conventionally luted control group (LD thickness 1.5 mm; fracture load 35.26 N; flexural strength 60.44 MPa) and the thinnest adhesively luted experimental group (LD thickness 0.6 mm; fracture load 28.97 N; flexural strength 90.01 MPa) in terms of fracture load and flexural strength. A fracture involving both the dentin and the LD of the bi-layered prismatic beam, but without any debonding between the LD and the dentin substrates of the broken specimen, was the most common failure mode observed on the adhesively luted samples. CONCLUSION: Compared to conventional cementation, when LD is bonded to dentin, the flexural properties of the whole system are improved, and the two different substrates seem to behave like a single unit. Once adhesively luted, 0.6-mm-thick LD has the same fracture load and flexural strength as that of the conventionally luted 1.5-mm-thick LD.

Safe clinical technique for increasing the occlusal vertical dimension in case of erosive wear and missing teeth.

A safe method to increase the occlusal vertical dimension (OVD) in patients with mild temporomandibular symptoms (such as tenderness upon palpation) is described. After a temporomandibular joint magnetic resonance (MR), an OVD increase was sought, pursuing pure rotational movement without condyle displacement. Prior to definitive rehabilitation, an additional MR confirmed steady and healthy condyle-disc-fossa relationships.

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.

Cytotoxic and Genotoxic Effects of Composite Resins on Cultured Human Gingival Fibroblasts.

The aim of the study was to evaluate the cytotoxic and genotoxic potential of five commercially available dental composite resins (CRs), investigating the effect of their quantifiable bisphenol-A-glycidyl-methacrylate (Bis-GMA) and/or triethylene glycol dimethacrylate (TEGDMA) release. Experiments were performed using the method of soaking extracts, which were derived from the immersion of the following CRs in the culture medium: Clearfil-Majesty-ES-2, GrandioSO, and Enamel-plus-HRi (Bis-GMA-based); Enamel-BioFunction and VenusDiamond (Bis-GMA-free). Human Gingival Fibroblasts (hGDFs) were employed as the cellular model to mimic in vitro the oral cavity milieu, where CRs simultaneously release various components. Cell metabolic activity, oxidative stress, and genotoxicity were used as cellular outcomes. Results showed that only VenusDiamond and Enamel-plus-HRi significantly affected the hGDF cell metabolic activity. In accordance with this, although no CR-derived extract induced a significantly detectable oxidative stress, only VenusDiamond and Enamel-plus-HRi induced significant genotoxicity. Our findings showed, for the CRs employed, a cytotoxic and genotoxic potential that did not seem to depend only on the actual Bis-GMA or TEGDMA content. Enamel-BioFunction appeared optimal in terms of cytotoxicity, and similar findings were observed for Clearfil-Majesty-ES-2 despite their different Bis-GMA/TEGDMA release patterns. This suggested that simply excluding one specific monomer from the CR formulation might not steadily turn out as a successful approach for improving their biocompatibility.

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.

An evaluation of luting agent application technique effect on fibre post retention.

OBJECTIVE: Aim of the study was to assess the bond strengths of three adhesive/resin cement/fibre post systems by using different application methods of the luting agent. METHODS: Three types of fibre post systems were selected for this study. ENA Post (Micerium), Anatomical Post (Dentalica), and Endo Light-Post (RTD) were luted in prepared root canals, using proprietary adhesive system and resin cement. Each group was divided into three subgroups (n=10). For each subgroup, a different technique was used to place the luting agent into post space: using a lentulo spiral; applying the cement onto the post surface; injecting the material with a specific syringe. A push-out test was performed on sections from apical, middle and coronal parts of each specimen. All fractured specimens were observed using a scanning electron microscope to identify the types of failure. RESULTS: Bond strengths were not statistically influenced by root region (p>0.05) but were significantly affected both by post/adhesive/cement system and by the application technique of the luting agent (p<0.05). The microscopic analysis of the specimens revealed a prevalence of post/cement and mixed failures. CONCLUSIONS: The best results with the push-out test were obtained when the luting agent was brought into the post space with lentulo spirals or specific syringes. Only ENA Post system showed similar bond strength values independently from the application method of the luting agent.

Influence of surface treatments on the flexural properties of fiber posts.

The aim of this study was to evaluate the effect of three post-surface treatments on flexural properties of fiber posts. Three types of posts were selected (n = 88 per post type). Four groups of specimens were prepared for each different post (n = 22). For the control group, posts were used as supplied by the manufacturers. Silanization, hydrofluoric etching, and sandblasting with 50 microm Al(2)O(3) were performed on post surfaces for each of the other groups. Two posts of each group were submitted to a qualitative scanning electron microscopy (SEM) analysis. Remaining specimens were positioned in a universal testing machine and a three-point bending test was conducted (n = 20) until fracturing of the posts. Flexural strengths and flexural modules were calculated and recorded. None of the surface pretreatments had a significant influence on the tested properties of the posts (p > 0.05). Visual analysis of SEM micrographs showed significant changes of post surfaces determined by each conditioning treatment, which could increase post-retentive properties.

Effect of application technique of luting agent on the retention of three types of fiber-reinforced post systems.

The aim of this study was to evaluate retentive strengths of three adhesive/resin cement/fiber post systems to the apical third of post-space dentin varying the application method of the luting agent. ENA post (Micerium, Avegno, Genova, Italy), FRC Postec Plus (Ivoclar Vivadent, Schaan, Liechtenstein), and Anatomical Post (Dentalica, Milano, Italy) were luted in prepared root canals using the adhesive system and resin cement provided by the respective manufacturer. Each group was randomly divided into three subgroups (n = 10) according to the technique used to place the luting agent into post space: using a lentulo spiral, applying the cement onto the post surface, and injecting the material with a specific syringe. A push-out test was performed on sections from the post-space apical part of each specimen. All fractured specimens were observed using a stereomicroscope. Bond strength values were not significantly affected by the application technique of the luting agent (p > 0.05). The ENA post system showed the highest retentive strengths. The other two post groups exhibited similar bond strengths to each other. Microscopic analysis revealed a prevalence of post/cement and mixed failures.

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® 2 (Group 3); and XP Bond® + Core-X™ 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.