Self-adhesive Cement Research Articles

Comparison of the effects of laser systems and cold atmospheric plasma on the surface roughness and shear bond strength of flexible hybrid ceramics.

The aim of this study was to compare the effects of laser systems and cold atmospheric plasma (CAP) on the surface roughness (Ra) and shear bond strength (SBS) of flexible hybrid ceramics (FHCs). Eighty FHC samples were divided into 5 groups to be subjected to surface treatments (hydrofluoric acid (HFA), HFA + 5W Er: YAG laser (HFA + 5WE), HFA + 3W Er: YAG laser (HFA + 3WE), HFA + ultrafast fiber laser (HFA + FL), and CAP). The Er: YAG laser (AT Fidelis Plus III, Fotona, Slovenia) was operated with a 0.9mm diameter tip, delivering 250mJ and 150mJ per pulse, with output powers of 5W and 3W, and fluences of 23,623J/cm² and 14,157J/cm², respectively, at a frequency of 20Hz and a pulse duration of 600 µs for 30s. The FL (FiberLAST Inc., Turkey) was applied with a 7mm spot size, 1mJ pulse energy, 20W output power, 100kHz repetition rate, ultrashort pulse length (100 ns), and the fluence of 1,820J/cm² for 7s. The CAP (PiezoBrush PZ3, Relyon Plasma, Germany) applied to the surfaces for 80s at a treatment speed of 5 cm2/s and 100% plasma power. After the Ra values were measured, each group was divided into 2 subgroups to be cemented with total-etch (TE) and self-adhesive (SA) resin cements. The SBS of all the samples was measured. One sample was randomly selected from each group, and the fractured surfaces were examined by SEM analysis. The significance level was at P < 0.05. HFA + FL had the highest Ra values, and there was no significant difference between HFA + FL and HFA + 5WE (P > 0.05). There was no difference in Ra between CAP and HFA (P > 0.05). The highest SBS values were observed for the samples cemented with TE after HFA + FL. The difference between the SBS values of the groups cemented with TE after CAP, HFA + 5WE, HFA + 3WE, and HFA + FL was not significant (P < 0.05). The use of FL may be a promising method to improve SBS without causing thermal damage when using TE or SA cements. CAP can be recommended as a practical and safe treatment with SA cement because it is suitable for chairside use with a handheld device and does not change the physical properties of the material.

Influence of Preheating Self-Adhesive Cements on the Degree of Conversion, Cell Migration, and Cell Viability

Enhancing the degree of polymerization can mitigate the cytotoxic effects of resinous materials, as residual monomers have been identified as a significant contributor to cytotoxicity. Hence, the aim of the current research was to evaluate the influence of preheating self-adhesive cements at 39 °C on cell migration, cytotoxicity, and degree of conversion. RelyX U200, Set PP, and MaxCem Elite were subjected to Fourier Transform Infrared Spectroscopy–Attenuated Total Reflection (FTIR–ATR). Self-adhesive resin cements were applied onto an ATR device, with samples subjected to either heated or room temperature conditions, followed by photoactivation. For the cytotoxicity analysis, extracts (24 h and 7 days) were placed in contact with NIH/3T3 cells. For cell migration, images were captured of each sample until the possible closure of the cleft occurred. A two-way analysis of variance (ANOVA) was conducted to assess the effect of preheating on the degree of conversion and cell viability within the self-adhesive cements tested. A significance level of 5% was set for statistical purposes. In the results of the degree of conversion, preheating did not improve the conversion of cements (p &gt; 0.05). For the 3-(4-5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT), preheating did not improve the results within 24 h, however, it generated positive results within 7 days for the Set PP resin cement (p &lt; 0.05). For cell migration, high rates of cell death were found in all groups. It is concluded that preheating at 39 °C causes a positive effect only in increasing the cell viability of the Set PP resin cement and that both materials analyzed are highly cytotoxic.

Effect of Laser Treatment of Root Dentine on Retention of Dental Fiber Post in Endodontically Treated Teeth: An In Vitro Study.

Introduction: The most common causes of fiber post-failure are inadequate restorations and dislodgement. This study aimed to evaluate fiber post-bond strength to dentin following Er,Cr:YSGG laser irradiation. Methods: A total of 65 human mandibular premolars with single roots were included. The 14 mm root length was instrumented with the rotary system using the crown-down technique. Gutta-percha was used for obturation, followed by conventional post space preparation. The samples were divided into two major groups: control (A) and Er,Cr:YSGG (2780 nm) laser group (B). The laser group was subdivided into (B1) 1.25 W, (B2) 1.5 W, and (B3) 1.75 W. All laser groups were set at 20 Hz, 10% and 30% water/air ratio. Fiber posts were cemented with selfadhesive cement. Each sample was divided horizontally into two slices, coronal and apical. The universal testing equipment was used to conduct a push-out test. All groups were examined by SEM and temperature changes. The statistical analysis was performed by using one-way ANOVA and Tukey HSD tests. Results: SEM images of all laser groups revealed the elimination of the smear layer and opened dentinal tubules, which was particularly noticeable in the apical region with no thermal risk to the periodontal tissue. In the push-out test, all laser groups had highly significant (P<0.001) increases in the bond strength of fiber post to dentin. The failure mode of the control group was a predominantly adhesive failure, whereas the laser groups were a predominantly mixed type. Conclusion: The three laser protocols can be used safely in the surface treatment of the fiber post space of endodontically treated teeth. Laser help to increase the bond strength of fiber post to dentin, especially in the apical area.

In Vitro Effect of Luting Cement on Fracture Resistance of Primary Maxillary Central Incisors with Fiber Posts.

Objectives: The use of fiber posts in endodontically treated primary maxillary central incisors improves the retention of composite resin restorations. The purpose of this study was to evaluate the effect of 4 different luting cements on fracture resistance of primary maxillary central incisors with fiber posts. Materials and Methods: In this in vitro study, 40 primary maxillary central incisors were endodontically treated and obturated with Metapex. They were then randomly divided into four groups (n=10) for cementation of fiber posts with GC Fuji I glass ionomer luting cement, Panavia F2.0 dual-cure luting cement, Panavia SA Luting Plus cement (self-adhesive), and TotalCem self-adhesive cement. After 1000 thermal cycles, the fracture resistance was measured. Data were statistically analyzed using ANOVA (alpha=0.05). Results: The mean fracture resistance was 267.07±130.01N in TotalCem, 257.27±102.56N in Panavia F2.0 dual-cure cement, 227.82±110.40N in Panavia SA Luting Plus self-adhesive cement, and 220.89±59.96N in GC Fuji I glass ionomer group. There was no statistically significant difference in fracture resistance among the four groups (P=0.714). Conclusion: Type of luting cement had no significant effect on fracture resistance of primary maxillary central incisors with fiber posts. Nonetheless, TotalCem yielded the highest fracture resistance. Considering its self-adhesive property and easy workability, it can be a good option for cementation of fiber posts in endodontically treated primary central incisors.

Adhesive Strength of Glass Fiber-Reinforced Posts with Silane Conditioning Versus Universal Adhesive System Conditioning: An In Vitro Study

Abstract Aim: The current study compared the push-out adhesive strength of glass fiber-reinforced posts with a silane-treated surface versus a universally adhesive-treated surface. In both cases, a universal self-adhesive cement was used. Materials and Methods: Thirty bovine teeth were used in an in vitro experiment. Through cutting, the root and coronal sections were divided. Subsequently, the manufacturer’s recommendations were followed for the placement of glass fiber-reinforced posts through root canal therapy, gutta-percha removal, and canal shaping. On the basis of how the posts were treated prior to cementation, the samples were split into three groups (n = 10). Posts in group A (control) did not get any prior treatment. Posts in group B had previously received a silane treatment. Posts in Group C had previously been coated with universal adhesive. Following the application of RelyX Ultimate universal self-adhesive cementation, the samples were segmented and subjected to a Push-Out test at a speed of 1 mm/min on a universal testing apparatus. Intergroup ANOVA was used to evaluate the adhesive strength means (measured in MPa), and Tukey’s post hoc test was performed afterward, with a significance level of P &lt; 0.05. Results: Compared to the glass fiber-reinforced posts pre-treated with silane (P = 0.003) and the control group (P &lt; 0.001), the adhesive strength of the posts pre-treated with universal adhesive was significantly higher. Similarly, the adhesive strength of the glass fiber-reinforced posts that had been pre-treated with silane was considerably higher than that of the control group (P = 0.012). Conclusion: Posts reinforced with glass fiber and pre-treated with universal adhesive exhibited notably greater adhesive strength compared to those pre-treated with silane. When compared to utilizing universal self-adhesive cement without pre-treatment, both pre-treatment techniques greatly increased the adhesive strength of glass fiber-reinforced posts.

Enhancing bonding of zirconia lithium silicate ceramics to dentin: The effect of surface treatment and resin cement

This laboratory study evaluated the influence of surface treatments on surface topography, and the bonding of CAD/CAM (computer-aided design computer-aided manufacturing) zirconia-containing lithium silicate (ZLS) surfaces to human dentin using various contemporary resin cements. Specimens from ZLS CAD/CAM blocks (Celtra™ Duo and Vita™ Suprinity) underwent three surface pretreatments: grinding only; 5 % hydrofluoric acid etching followed by application of a silane coupling agent, and a self-etching ceramic primer. The specimens were bonded to a flat exposed dentin surface using two etch-and-rinse and two self-adhesive resin cements, and then sectioned into microspecimens for microtensile bond strength (μTBS) testing. Failure modes of bonded surfaces, and ceramic surface roughness and topography were assessed. Results indicated that surface treatment was essential for ZLS-dentin bonding. Hydrofluoric acid and silane, along with the self-etching primer resulted in comparable strengths and outperformed the control group. Etch-and-rinse cements yielded significantly higher μTBS than self-adhesive cements. Significant differences in surface roughness and topography were observed among the treatment groups. Hydrofluoric acid exhibited the highest roughness parameters and most prominent surface changes. These findings highlight the importance of surface treatment for enhancing zirconia-containing lithium silicate bonding to dentin, and emphasize the critical role of the resin cement choice in optimizing dental restorative outcomes.

Effect of curing mode of resin composite cements on water sorption, color stability, and biaxial flexural strength

ObjectivesTo determine whether water sorption and solubility of a recently introduced self-adhesive cement is comparable to two clinically tested resin composite cements after thermal aging, and if this is affected by the curing mode. Whether water sorption is correlated with color difference and biaxial flexural strength was also investigated. MethodsWater sorption and solubility of three resin composite cements {RelyX Universal (RUV), (Panavia V5 (PV5), Panavia SA plus (PSA)} were measured after thermal aging. Disk-shaped specimens were either light-cured or autopolymerized (n = 15 per group). Color difference ΔE00 and biaxial flexural strength were also obtained. ResultsSorption was highest for RUV (auto: 54.9 ± 9.0 µg/mm3, light: 49.7 ± 4.9 µg/mm3), followed by PSA (auto: 37.7 ± 1.4 µg/mm3, light: 34.5 ± 1.1 µg/mm3) and PV5 (auto: 21.7 ± 0.7 µg/mm3, light: 22.1 ± 0.4 µg/mm3). Light-curing reduced solubility values, particularly for RUV (from 60.7 ± 20.8 µg/mm3 to 6.4 ± 0.8 µg/mm3). Color differences of ΔE00 > 1.8 (considered clinically not acceptable) were noted after aging for RUV and PSA. Sorption and ΔE00 values after aging were correlated linearly (R2 = 0.970). Biaxial flexural strength values were highest for PV5 (light: 153.4 ± 15.9 MPa; auto: 133.2 ± 18.0 MPa) and lowest for RUV (light: 99.3 ± 12.8 MPa; auto: 35.1 ± 8.3 MPa). SignificanceLight-curing has beneficial effects on sorption, color stability, and biaxial flexural strength of resin composite cements. Cements containing 2-hydroxymethacrylate such as RUV and PSA are more prone to water sorption and color changes.

In Vitro Effects of Chlorhexidine and Isopropyl Alcohol Conditioning Agents on Immediate and Late Bond Strength of Fiber Posts Dentin.

Objectives: This study assessed the effect of chlorhexidine (CHX) and isopropyl alcohol (IA) on immediate and late pushout bond strength (PBS) of fiber posts to dentin. Materials and Methods: In this in vitro study, 54 single-canal premolars were endodontically treated, and randomly assigned to 3 groups (N=18) for root dentin conditioning with distilled water (control), 2% CHX, and 70% IA after post space preparation. Fiber posts were cemented with TheraCem self-adhesive cement, and each group was subdivided into two subgroups (N=9) for PBS measurement immediately after bonding, and after 5000 thermal cycles (5-55°C). The roots were then sectioned, and their PBS was measured. The mode of failure was evaluated under a stereomicroscope at ×40 magnification. Data were analyzed by repeated measures ANOVA and Tukey's test (alpha=0.05). Results: The highest PBS was noted in the IA group (21.12 MPa) after 24 hours and the lowest PBS belonged to the control group after thermocycling (7.48 MPa). The immediate and post-thermocycling PBS were significantly lower in the control group than the CHX group (P<0.05). The PBS in both the control and CHX groups was lower than that in the IA group (P<0.001). Regardless of the type of detergent, a significant reduction in PBS was observed after thermocycling (P<0.003). The PBS significantly decreased from the cervical towards the apical region in all groups (P<0.001). Conclusion: According to the results, application of IA before the self-adhesive cement effectively improved the immediate and late PBS, and was significantly more effective than CHX.

Marginal Leakage in Interfaces Formed by Bovine Dentin and Adhesive Cements Applied with Different Bonding Techniques

Objectives: The aim of this in vitro study was to evaluate the marginal microleakage in interfaces formed by bovine dentin and adhesive cements applied with different bonding techniques. Materials and Methods: Thirty bovine teeth dentin blocks measuring 5 mm x 5 mm x 1 mm were made with one side completely in dentin substract (20 mm2). The dentin blocks were randomly divided into three groups according to the cementation technique used: CTS+RX (conventional 3-step adhesive + dual-activation resin cement), SBS+RX (single-bottle self-etching adhesive + dual-activation resin cement), and SAC (self-adhesive cement). A photopolymerizable composite resin block with the same dimensions was fixed on the dentin block according to the instructions for each adhesive technique. The dentin-composite resin blocks made with each adhesive technique were separated into subgroups (n = 5) for 7 days (control) and for 6 months of water storage. After each period, the blocks were individually immersed in test tubes containing neutral methylene blue dye for 2 hours. The samples were washed, dried, and evaluated with a stereoscopic magnifying glass, and the amount of infiltrated pigment was analyzed using spectrophotometry (Beckman DU 65). The data were submitted to two-way ANOVA and Tukey’s test (5%). Results: Microleakage level for the conventional 3-step or self-etching technique remained similar for 7 days (18 ± 25 and 43 ± 45 μm, respectively) or 6 months (42 ± 55 and 52 ± 87 μm, respectively). The self-adhesive technique showed higher microleakage levels for 7-day (263 ± 98 μm) and 6-month periods (441 ± 226 μm) compared to other adhesive techniques. There was a statistically significant difference between evaluation times only for the self-adhesive technique. Conclusions: Higher microleakage levels by storage in water occurred with the self-adhesive technique in both evaluation periods. Clinical Relevance: The different microleakage levels promoted at the dentin-composite resin interface should be considered in adhesive clinical procedures in relation to long-term use.

Assessment of Degree of Conversion and Volumetric Shrinkage of Novel Self-Adhesive Cement.

The degree of monomer conversion and polymerization shrinkage are two of the main reasons for potential adhesion failure between the tooth structure and the restoration substrate. To evaluate the degree of conversion and polymerization shrinkage of a newly developed self-adhesive resin cement, the degree of conversion (DC) was measured using FTIR under different activation modes, temperatures, and times. Volumetric shrinkage was tested using the AcuVol video imaging method. The experimental cement showed a higher DC than other cements under self-curing. The DC of the experimental cement was higher than that of other cements, except SpeedCem Plus under light curing. The experimental cement had a higher DC than other cements, except SpeedCem Plus in some conditions under dual curing. All self-adhesive cements had a higher DC at 37 °C than at 23 °C under self-curing, and there was no statistical difference between 23 °C and 37 °C under light curing. All self-adhesive cements showed a significantly higher DC at 10 min than at 5 min under self-curing. There was no statistical difference between 5 min and 10 min for most cements under dual curing. All self-adhesive cements statistically had the same volumetric shrinkage under light curing and self-curing. The newly developed self-adhesive resin cement exhibited a higher degree of conversion and similar volumetric shrinkage compared to these commercial self-adhesive resin cements.

Influence of using different translucent composite resins for customizing fiber post on the bond strength of self-adhesive cement to root dentin.

This study evaluated the influence of different translucent resins (Z350 and Opallis) for customizing fiber posts and light-curing the cementation system using different LED equipment (V, Valo or R, Radii-Cal) on the bond strength and adhesive failure pattern at 24 h and 6 months. Eighty roots were prepared and divided into 4 groups (n=20): ZV (Z350 resin and LED Valo), ZR (Z350 resin and LED Radii-Cal), OV (Opallis resin and LED Valo), OR (Opallis resin and LED Radii-Cal). After post space preparation, the fiber post was customized and cemented with self-adhesive cement and light-curing using V or R LED equipment. Bond strength values were submitted to 2-way ANOVA test. ZV and ZR showed higher bond strength values than the other groups at 6 months of evaluation (p<0.05). The Z350 resin has a favorable influence on the bond strength of self-adhesive cement to root dentin, regardless of the LED polymerization equipment used.

Push-Out Bond Strength of Fiber-Reinforced Post Using Various Post Space Irrigation Treatments.

Objective: This study aims to provide the impact of different endodontic irrigation treatments after post space preparation on the push-out bond strength of fiber posts to dentin using self-adhesive cements. Methods and Materials: A total of 180 extracted premolar teeth were selected. The canals were instrumented by and then were filled. After preparing the post space, teeth were divided into 12 groups according to irrigants (normal saline solution; 17% EDTA [ethylenediaminetetraacetic acid] + 5.25% NaOCl [sodium hypochlorite]; 17% EDTA; 5.25% NaOCl; and 1.2% chlorhexidine [CHX]) and irrigation technique (conventional syringe irrigation [CSI] and passive ultrasonic irrigation [PUI]). After cementation, the samples were sectioned to obtain 1-mm disks from coronal and apical parts, a push-out test was performed using a universal testing machine (Z050, Zwick/Roell, Ulm, Germany) at a speed of 1 mm/min. The data were analyzed using one-way analysis of variance (ANOVA) and Mann-Whitney U tests. Results: The push-out bond strength was higher in coronal segment in comparison to apical segment. The highest push-out bond strength value was related to NaOCl + EDTA using PUI (12.39 ± 1.08). There are significant differences when comparing NaOCl + EDTA group with EDTA group using CSI or PUI technique (p < 0.05) except in coronal region with CSI technique. In both apical and coronal regions, phosphoric acid irrigation was found to be similar to normal saline solution and CHX groups regardless of activation technique. Conclusion: The push-out bond strength values were significantly affected by the irrigation protocol. Using PUI and 17% EDTA + 5.25% NaOCl in apical region could be an effective irrigant for smear layer removal after post space preparation.

Effects of a relined fiberglass post with conventional and self-adhesive resin cement.

This study was conducted to evaluate the mechanical properties of relined and non-relined fiberglass posts when cemented to root canal dentin using a conventional dual-cure resin cement or a self-adhesive resin cement. Two types of resin cements were utilized: conventional and self-adhesive. Additionally, 2 cementation protocols were employed, involving relined and non-relined fiberglass posts. In total, 72 bovine incisors were cemented and subjected to push-out bond strength testing (n = 10) followed by failure mode analysis. The cross-sectional microhardness (n = 5) was assessed along the root canal, and interface analyses (n = 3) were conducted using scanning electron microscopy (SEM). Data from the push-out bond strength and cross-sectional microhardness tests were analyzed via 3-way analysis of variance and the Bonferroni post-hoc test (α = 0.05). For non-relined fiberglass posts, conventional resin cement exhibited higher push-out bond strength than self-adhesive cement. Relined fiberglass posts yielded comparable results between the resin cements. Type II failure was the most common failure mode for both resin cements, regardless of cementation protocol. The use of relined fiberglass posts improved the cross-sectional microhardness values for both cements. SEM images revealed voids and bubbles in the incisors with non-relined fiberglass posts. Mechanical properties were impacted by the cementation protocol. Relined fiberglass posts presented the highest push-out bond strength and cross-sectional microhardness values, regardless of the resin cement used (conventional dual-cure or self-adhesive). Conversely, for non-relined fiberglass posts, the conventional dual-cure resin cement yielded superior results to the self-adhesive resin cement.

Bond Strength of a Novel Universal Resin Cement to Dentin with or without an Adhesive Bonding Agent: An In Vitro Study.

The purpose of this study was to evaluate the bond strength and fracture mode of universal resin cement to dentin compared to self-adhesive and adhesive resin cement with and without an adhesive bonding agent. Seventy-two molar teeth were sectioned to expose coronal dentin, divided into three groups, and assigned to RelyX Universal (universal), RelyX Ultimate (adhesive), or RelyX Unicem 2 (self-adhesive) cements from 3M. The 3 groups were further subdivided into 2 subgroups of 12 specimens each, with or without the use of an adhesive bonding agent. Lithium-disilicate discs were bonded to the dentin surface using the cements, stored for 24 hours in distilled water, and subjected to 2,000 thermocycles before shear bond strength testing and fracture mode analysis. Significant differences in bond strength and fracture mode were found between groups based on cement or the use of a bonding agent. Both the universal and adhesive cements had significantly greater bond strengths to dentin with the use of a bonding agent versus no bonding agent. With the self-adhesive cement, there was no significant increase in bond strength to dentin with the use of a bonding agent. The novel universal resin cement had similar bond strengths to dentin as the adhesive cement with the use of a bonding agent, and similar bond strengths as the self-adhesive cement without the use of a bonding agent. The adhesively bonded universal cement had the greatest percentage of mixed and cohesive fractures. When greater adhesion is needed clinically, the novel universal resin cement may be used with an adhesive bonding agent. However, when less adhesion is needed, it could be used without a bonding agent in self-adhesive mode.

MDP-salts as an adhesion promoter with MDP-primers and self-adhesive resin cement for zirconia cementation

PurposeTo evaluate the effect of zirconia priming with MDP-Salt before MDP containing primers and self-adhesive cement on the shear bond strength.Materials and methodsFully sintered high translucent zirconia specimens (n = 120) were assigned into 2 groups (n = 60 each): Control (No Pretreatment) and Methacryloyloxydecyl dihydrogen phosphate salt (MDP-Salt) pretreated. Each group was divided into 3 subgroups (n = 20) according to cementation protocol: 1) MDP + Silane primer and conventional resin cement, 2) MDP+ Bisphenyl dimethacrylate (BPDM) primer and conventional resin cement, and 3) MDP containing self-adhesive resin cement. Shear bond strength (SBS) was measured after 10,000 thermocycling. Contact angle was measured for tested groups. Surface topography was assessed using a 3D confocal laser scanning microscope (CLSM). Weibull analysis was performed for SBS and one-way ANOVA for contact angle and surface topography measurements (α = 0.05).ResultsThe use of MDP-Salt significantly improved the SBS (p < .05) for all tested subgroups. Self-adhesive cement showed an insignificant difference with MDP + Silane group for both groups (p > .05). MDP + BPDM showed a significantly lower characteristic strength compared to self-adhesive resin cement when both were pretreated with MDP-Salt. No difference between all tested groups in the surface topographic measurements while MDP-Salt showed the highest contact angle.ConclusionMDP-Salt pretreatment can improve bonding performance between zirconia and MDP containing products.

Medium-term evaluation of the bond strength and dentin penetration of self-adhesive resin cements to root dentin.

Medium-term evaluate the bond strength and tag formation in root dentin using self-adhesive cements Maxcem Elite (MCE), Relyx U200 (RU2), SeT PP (SPP) and Megalink (MGL) compared to conventional cement Relyx ARC (ARC) for glass fibre post cementation. One hundred bovine incisors roots were endodontically treated and divided into 5 groups (n = 20) according to the cementation system: MCE, RU2, SPP, MGL and ARC. All cementation systems were evaluated at 24 h (1) and 12 months (2) after post cementation. Specimens from the cervical, middle and apical thirds of the root were submitted to push-out bond strength test and confocal laser microscopy to verify the dentin penetration. The adhesive failure mode was classified as adhesive, cohesive and mixed. Data were analysed by one-way ANOVA and Tukey tests (α = 5%). ARC-1 and ARC-12 showed the highest bond strength (P < 0.05). ARC showed the greatest tag extension, regardless of the third (P < 0.05). The most frequent failure mode in the 24-h analysis was cohesive, regardless of the cement used. For the 12-month analysis, mixed failure was the most frequent. Conventional cement (ARC) showed the highest bond strength and tag extension, regardless of the evaluation period. In all cementation systems, the bond strength decreased after 12 months. © 2023 Australian Dental Association.

KNOWLEDGE OF DENTAL SURGEONS IN THE SELECTION AND CEMENTATION OF FIBERGLASS POSTS

The aim of this study is to record the knowledge of dentists in relation to the selection and cementation technique of the fiberglass post in the daily routine of dental professionals to check which fiberglass post brand and anatomy are most used; to describe the reasons that lead the professionals to choose this technique, as well as analyze the types of cement available and the one most used by dentists in cementing the fiberglass post. In addition to helping dental students with information on the topic, taking into account the fact that this type of retainer is a great choice for the reconstruction of endodontically treated teeth, as it is a cost-effective material, it is resistant to chewing forces, aesthetic and simple technique. To carry out the research, an electronic questionnaire was applied, with objective questions for dental students from Faculdade Patos de Minas (FPM), via a Google Forms form, aiming to acquire data on how the dentists use the fiberglass post. Given the results obtained, among the materials used for cementing the post, there was a great preference for dual resin cement, as it has a good adhesion and resistance, however, it has an unsatisfactory polymerization. Furthermore, it was observed that the self-adhesive resin cement launched on the market recently has been highly praised for presenting several advantages. It is concluded that dual resin cement is the most used by dentists in dental offices today, but self-adhesive cement has been the best choice, as it presents properties similar to previous cements and resistance equivalent to conventional cements according to the literature researched.

Fracture resistance of monolithic translucent zirconia crown bonded with different self-adhesive resin cement: influence of MDP-containing zirconia primer after aging

ObjectivesSuccessful ceramic restorations depend on the strong bonding with resin cement and even stress distribution. The aim of this study was to evaluate the impact of adding MDP-containing zirconia primer before self-adhesive resin cements with different functional acidic monomers on fracture resistance of monolithic zirconia crown.Materials and methodsEighty defect-free human maxillary premolars were divided according to the cement type and application of MDP-containing zirconia primer into eight groups (n = 10): Calibra Universal (C), Calibra Universal combined with zirconia primer (CZ), RelyX U200 (R), RelyXU200 combined with zirconia primer (RZ), Panavia SA Cement Plus (P), Panavia SA Cement Plus combined with zirconia primer (PZ), Multilink Speed (M), and Multilink Speed combined with zirconia primer (MZ). After teeth preparation and fabrication of zirconia crowns, each crown was bonded to its corresponding tooth. All specimens were subjected to 10,000 thermocycles between 5 and 55°C, followed by cyclic load (50 N) for 240,000 cycles. Each specimen was subjected to a static axial load until fracture using universal testing machine and the fracture load was recorded. The fracture mode studied and recorded. The fracture load results were analyzed using two-way ANOVA test (α = 0.05).ResultsA significant interaction (P = 0.038) of combining MDP-containing zirconia primer and cement type on fracture resistance of monolithic zirconia crown was detected. The mean fracture load values of zirconia crown were significantly influenced by the combined application of the MDP-containing zirconia primer with Calibra Universal (P = 0.01), RelyX U200 (P < 0.001), and Multilink Speed (P = 0.038), while there was no significant difference with Panavia SA Cement Plus (P = 0.660). There was significant difference (F = 20.69, P < 0.001) between the mean fracture loads of groups with self-adhesive cements (C, R, P, and M groups). The highest fracture load was recorded with RZ group (2446.90 ± 126.72 N) while the lowest fracture load was recorded with C group (1623.18 ± 149.86 N).ConclusionsThe self-adhesive resin cement with different acidic functional monomer affects the fracture resistance of monolithic zirconia crown. Application of MDP-containing primer could improve the fracture resistance of monolithic zirconia crown with most self-adhesive cements. The application of an MDP-containing primer had no impact on the fracture resistance of monolithic translucent zirconia crown bonded by MDP-containing self-adhesive resin cement.

Effect of Attenuated Light Through Translucent Zirconia on the Interfacial Adaptation and Polymerization of Resin Cements.

The first objective was to determine if dual-curing of resin cement with reduced light could affect interfacial adaptations of zirconia restoration. The second objective was to examine whether cement type and pretreatment method of universal adhesive affected interfacial adaptation. The final objective was to compare the polymerization degree of cement under different reduced-light conditions. Inlay cavities were prepared on extracted third molars. Translucent zirconia restorations were milled using Katana UTML (Kuraray Noritake) in three groups with restoration thicknesses of 1, 2, and 3 mm, respectively. Each group had three subgroups using different cementation methods. For subgroup 1, restorations were cemented with self-adhesive cement. For subgroup 2, universal adhesive was applied and light cured. After the restoration was seated with conventional resin cement, light curing was performed. For subgroup 3, after adhesive was applied, the restoration was seated with conventional resin cement. Light curing was performed for the adhesive and cement simultaneously. After thermocycling, interfacial adaptation at the restoration-tooth interface was investigated using swept-source optical coherence tomography imaging. Finally, polymerization shrinkage of the cement was measured using a linometer and compared under the conditions of different zirconia thicknesses and light-curing durations. Interfacial adaptation varied signficantly depending on the zirconia thickness, pretreatment, polymerization mode and cements used (p < 0.05). The effects of the adhesive and polymerization shrinkage differed signficantly, depending on the reduced light under the zirconia (p < 0.05). Lower curing-light irradiance may lead to inferior adaptation and lower polymerization of the cement. Polymerization of resin cement can differ depending on the light irradiance and exposure duration.

Influence of medium-translucency monolithic zirconia thicknesses and light-curing time on the polymerization of dual-cure resin cements

Aim: To investigate and compare the effects of different thicknesses of medium-translucency monolithic zirconia and light curing times on the polymerization of two types of dual-cured resin cement. Methods: A total of 200 cement specimens were prepared from TheraCem and RelyX U200 cement. The specimens were divided into 5 groups: Group I, without interposing zirconia; Group II, 0.50 mm thickness; Group III, 1.00 mm; Group IV, 1.50 mm; and Group V, 2.00 mm thickness. Each group was subdivided into (1) RelyX U200 and (2) TheraCem. Each subgroup was subdivided according to the light-curing time into (a) 20 s and (b) 40 s (n =5). The polymerization was tested using Fourier-transform infrared (FTIR) spectroscopy and a Vickers microhardness tester. The data were statistically analyzed using ANOVA, an independent sample t-test, and Tukey’s test at a significance level of 0.05. Results: The control group had the highest values of DC and VMH, followed by 0.50, 1.00, and 1.50 mm, respectively, while the 2.00 mm group showed the lowest values. The specimens irradiated for 40 s had greater DC and VMH than those irradiated for 20 s. RelyX U200 revealed higher values for both parameters compared to TheraCem cement. Conclusion: The polymerization of selfadhesive cement depends on the thickness of the monolithic zirconia, the light curing time, and the composition of the cement. The cement should be irradiated for a longer period than recommended to overcome the light attenuation of zirconia. TEGDMA-based self-adhesive cement showed a higher DC and VMH than BISGMA-based cement.