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1.
J Adhes Dent ; 23(2): 91-110, 2021 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-33825424

RESUMEN

PURPOSE: The goals of this review are (1) to describe the evidence behind the use of ceramics vs composite resin to restore teeth with anterior veneers using a minimally-invasive strategy; and (2) to discuss the choice of materials and techniques for anterior veneer restorations. OVERVIEW: In recent years new adhesive restorative materials and techniques have been introduced in dentistry, including nanofilled composite resins for direct restorations, new ceramic materials that combine esthetics and strength, and polymer/ceramic materials for indirect restorations that are fabricated chairside using CAD/CAM technology, allowing the dentist to design, mill, and cement the restoration in one session. In spite of the novelty and new technology behind the introduction of new materials, the available evidence that backs some of these materials does not justify their use over similar materials or techniques that have been used by dentists for some years. Notwithstanding the success of laminate veneers and the popularity of new materials and digital techniques, the classical direct composite resin veneer is still very popular among clinicians and taught in dental schools and continuing education courses. Direct composite resin veneers are usually more affordable than indirect veneers, less invasive of the tooth structure, and easier to repair. Current composite resin materials can be finished to a tooth-like appearance, but they are susceptible to alterations of the surface gloss and potential discoloration of the composite resin. On the other hand, the preparation for indirect veneers is generally more invasive and the respective restorations are more difficult to repair. In addition, the esthetic outcome of bonded ceramic restorations still depends on the clinical behavior of the dentin adhesive and resin luting cement used to bond the restoration to the tooth structure. CONCLUSIONS: The ultimate goals of any restorative treatment are to restore function and esthetics, prevent recurrent caries lesions and bacterial leakage into the pulp space, save tooth structure, and promote the well-being of our patients. The armamentarium of new dental materials for esthetic clinical procedures has increased exponentially in the last few years. The use of different materials and techniques for anterior veneer restorations must be based on sound evidence rather than on the marketing hype or testimonials.


Asunto(s)
Resinas Compuestas , Coronas con Frente Estético , Cerámica , Materiales Dentales , Porcelana Dental , Humanos , Cementos de Resina
2.
J Adhes Dent ; 23(2): 113-119, 2021 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-33825425

RESUMEN

PURPOSE: To evaluate the influence of different surface treatments of two CAD/CAM glass ceramics on surface topography, shear bond strength of composite cement, flexural strength, and elastic modulus. MATERIALS AND METHODS: Two ceramics were evaluated: lithium-disilicate (LDS) and zirconia-reinforced lithium silicate (ZLS) glass ceramics. Glass ceramics were sintered and the surfaces were sandblasted (SBL) or etched with 9% hydrofluoric acid for 10 s (HF10), 20 s (HF20) or 30 s (HF30). The treated surfaces were analyzed using scanning electron microscopy (n = 3) to evaluate the etching pattern. For bond strength testing, ceramic samples were silanized after treatments and an adhesive was applied to the surface. Afterwards, a silicone mold was used to build composite-cement cylinders, which were tested after 24 h or one year of water storage (n = 10). Flexural strength and modulus were assessed using a 3-point bending test (n = 15). The data were subjected to statistical analysis at a pre-set α = 0.05. RESULTS: SBL and HF resulted in different surface topographies. Increased HF etching time influenced the surface dissolution level and exposition of crystals for LDS, while no effect of etching time was observed for ZLS. After one year, the bond strength to LDS significantly decreased, regardless of treatments. For ZLS, HF10 and HF20 showed stable bond strengths over time. SBL yielded the lowest bond strength for both ceramics and statistically significantly reduced the flexural strength of ZLS. The flexural strength and elastic modulus of ceramics were not affected by different etching times. CONCLUSION: Bonding stability depended on the glass ceramic and the pretreatment method employed. HF etching did not change the mechanical properties of the ceramics and is indicated as a ceramic treatment for bonding.


Asunto(s)
Recubrimiento Dental Adhesivo , Ácido Fluorhídrico , Cerámica , Porcelana Dental , Resistencia Flexional , Ensayo de Materiales , Cementos de Resina , Propiedades de Superficie
3.
J Adhes Dent ; 23(2): 133-143, 2021 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-33825427

RESUMEN

PURPOSE: To evaluate the effect of different etching times of a self-etching ceramic primer on the microshear bond strength (µSBS) and topographic surface pattern of a lithium-disilicate glass-ceramic. MATERIALS AND METHODS: Ceramic slices were subjected to an in-lab simulation of CAD/CAM milling and randomly allocated to 10 groups (n = 35) considering two factors: "surface treatment" in 5 levels - one control group (5% hydrofluoric acid + silane application [HF5+SIL]), and 4 experimental groups using ceramic etching/primer (Monobond Etch & Prime, E&P) with different passive application times (40 s, 2 min, 5 min, or 10 min); and "aging" factor in 2 levels - short-term (after 24 h), or long-term (storage for 180 days + 12,000 thermal cycles). Composite cement cylinders were built and µSBS tests were run in a universal testing machine. The failure patterns were categorized, and complementary analyses with SEM and Atomic Force Microscopy (AFM) were performed. RESULTS: The groups showed statistically similar bond strengths in the short term (range 22.4 to 25.1 MPa). However, only the E&P 20s+40s (19.3 MPa) and E&P 20s+5min (21.5 MPa) groups maintained stable bond strength in the long term, and HF5+SIL (17.1 MPa) presented statistically significantly lower values than did E&P 20s+5min. The failure pattern was predominantly adhesive. The increased application time of the ceramic primer promoted greater dissolution of the glass matrix; thus, the E&P 20s+10min group presented the most complex surface characteristics in the fractal dimension analysis. CONCLUSION: The self-etching ceramic primer can be used as an alternative to classical conditioning with HF plus silane, promoting stable bond strength for etching times of 40 s or 5 min of passive application.


Asunto(s)
Recubrimiento Dental Adhesivo , Litio , Cerámica , Porcelana Dental , Ácido Fluorhídrico , Ensayo de Materiales , Cementos de Resina , Silanos , Propiedades de Superficie
4.
J Adhes Dent ; 23(2): 145-158, 2021 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-33825428

RESUMEN

PURPOSE: To investigate the impact of pretreatment and conditioning on shear bond strength (SBS), surface free energy (SFE) and surface roughness (SR) between polyetheretherketone (PEEK) and cold-cured polymethylmethacrylate (PMMA). MATERIALS AND METHODS: PEEK substrates (Dentokeep PEEK Disc, nt-trading) were air abraded with Al2O3 particles of different grain sizes applied with varying pressure at 1) 0.2 MPa - 50 µm Al2O3; 2) 0.4 MPa - 50 µm Al2O3; 3) 0.2 MPa - 110 µm Al2O3; 4) 0.4 MPa - 110 µm Al2O3; or 5) without air abrasion (n = 172/group). Surface properties were quantified using SFE and SR (n = 10/group), and scanning electron microscope imaging (n = 2/group). Substrates were conditioned with a) Visio.link (VL, Bredent); b) Scotchbond Universal (SU, 3M Oral Care); c) Bonding Fluid (BF, Schütz Dental); or d) without conditioning (WC; n = 40/subgroup) and bonded to the polymer (Futura Jet, Schütz Dental). SBS and fracture types were determined before and after 10,000 thermal cycles (n = 20/subgroup). Univariate ANOVA, Kruskal-Wallis test, Mann-Whitney U-test, Kaplan-Meier survival estimates, and Weibull distribution were computed (p < 0.05). Ciba-Geigy tables and the chi-squared test were used to analyze fracture type distributions. RESULTS: An increase in particle size and pressure resulted in similar or increased SBS, Weibull characteristic strength, and Weibull moduli (p < 0.001 - 0.046). The lowest results were observed for the control group (without air abrasion), while pretreatment with 0.4 MPa - 110 µm Al2O3 presented the highest values (p < 0.001). In comparison with the other conditioning procedures, VL showed high (p < 0.001 - 0.03), and SU and WC low SBS (p < 0.001 - 0.006). Although it did not influence SFE, an increase in particle size and pressure led to an increased SR (p < 0.001). CONCLUSION: Pretreatment with 0.4 MPa - 110 µm Al2O3 can be recommended to increase bonding properties between PEEK and PMMA. Application of adhesives such as VL can enhance SBS further.


Asunto(s)
Recubrimiento Dental Adhesivo , Polimetil Metacrilato , Abrasión Dental por Aire , Análisis del Estrés Dental , Dentaduras , Cetonas , Ensayo de Materiales , Polietilenglicoles , Cementos de Resina , Resistencia al Corte , Propiedades de Superficie
5.
J Adhes Dent ; 23(2): 159-165, 2021 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-33825429

RESUMEN

PURPOSE: To evaluate the effect of inclusion of two dimethyl sulfoxide (DMSO) concentrations in simplified etch-and-rinse adhesives on dentin bonding durability after three years of water storage. MATERIALS AND METHODS: Forty-two caries-free third molars were divided into six experimental groups (n = 7) according to the following factors: 1) adhesive (Adper Single Bond 2 [SB], 3M Oral Care; Prime&Bond 2.1 [PB], Dentsply Sirona); 2) concentration of DMSO (control group: 0.0% DMSO; addition of 0.2% DMSO [0.2] and 2% DMSO [2.0]). After completing restoration, specimens were stored in water (37°C) for 24 h, sectioned into adhesive-dentin sticks (0.8 mm2), tested for microtensile bond strength (µTBS) at 0.5 mm/min, and examined for nanoleakage (NL) using SEM immediately thereafter or after three years of water storage. Data were subjected to a three-way repeated-measures ANOVA and Tukey's test (α = 0.05) for each property evaluated. RESULTS: After three years of water storage, for both adhesives, the incorporation of 2% DMSO maintained the µTBS when compared to immediate µTBS (p > 0.05). In general, SB resulted in a statistically significantly higher mean of µTBS compared to PB, independent of the DMSO concentration after water storage (p < 0.05). Furthermore, the amount of NL was lower and practically limited to the hybrid layer given the concentrations of 0.2% and 2% DMSO for both tested adhesives after three years. CONCLUSION: The incorporation of DMSO in simplified etch-and-rinse adhesives maintains the long-term stability of the dentin bond.


Asunto(s)
Recubrimiento Dental Adhesivo , Recubrimientos Dentinarios , Dentina , Dimetilsulfóxido , Ensayo de Materiales , Cementos de Resina , Resistencia a la Tracción , Agua
6.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 56(4): 342-348, 2021 Apr 09.
Artículo en Chino | MEDLINE | ID: mdl-33832035

RESUMEN

Objective: To explore the effect of subpressure on the bonding strength of resin to polycrystalline particulates modified zirconia ceramic. Methods: One hundred and twenty pre-sintered zirconia discs were prepared and divided into the control group, the sandblasting group and the 30, 50, 70 s acid etching group (24 per group) by the random number table method. There was no additional treatment in the control group and sandblasting group before sinering. The 30, 50, and 70 s acid etching groups were immersed in HF for 30, 50, 70 s, respectively, and then they were placed into CaCl2 solution for 90 s and dipped in NaOH solution at 80 ℃ for 2 h. After sintering, the sandblasting group was subjected to sandblasting. The surface tomography and roughness were tested. According to whether subpressure was applied or not after the adhesives were applied, each group was randomly divided into two subgroups with a random number table: a subpressure subgroup and a normal pressure subgroup (12 per subgroup). Resin columns were bonded to these specimens. Shear bonding strength (SBS) test was conducted and the bonding interface, fracture surface and failure mode were analyzed. Results: The surface of control group was smooth, and its roughness was (0.24±0.11) µm. The rough surface was formed after sandblasting in the sandblasting group, and its roughness was (0.95±0.12) µm. The surface roughness of 30, 50, 70 s acid etching groups [(0.60±0.15), (1.04±0.11), (1.57±0.16) µm] increased as the HF immersion time prolonged, and the difference in surface roughness of zirconia specimens among each group was statistically significant (P<0.05). The SBS values between zirconia and resin of all the subpressure subgroups, namely: the control group, the sandblasting group, and the 30, 50, 70 s acid etching group [(13.56±1.19), (20.98±2.11), (17.37±2.44), (24.19±2.97), (21.36±2.16) MPa] were significantly stronger than those in the normal pressure subgroups, namely: the control group, sandblasting group, 30, 50, 70 s acid etching group [(10.74±0.93), (18.47±2.14), (14.81±1.54), (20.74±2.56), (17.75±2.54) MPa] (P<0.05). No obvious gaps and bubbles were observed in the bonding interfaces in subpressure subgroups. The proportion of mixed failure was significantly increased after applying subpressure (P<0.05). Conclusions: The subpressure can effectively enhance the bonding strength between the resin and polycrystalline particulates modified zirconia ceramic and improve the bonding effect.


Asunto(s)
Recubrimiento Dental Adhesivo , Cementos de Resina , Cerámica , Cementos Dentales , Porcelana Dental , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Resistencia al Corte , Propiedades de Superficie , Circonio
7.
Dental Press J Orthod ; 26(1): e2119150, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33729290

RESUMEN

INTRODUCTION: Third generation of LED light curing units might be used in short exposure periods for orthodontic brackets bonding. OBJECTIVE: This study evaluated the effect of the different radiant exposure (RE) values: Manufacturers' instructions (MI), ½ MI, 1/4 MI and Turbo mode. Two third-generation LED curing units were used: VALO® and Bluephase 20i® . The degree of conversion (DC) and Vickers hardness (VHN) of an orthodontic composite (OC) (Transbond XT) under metallic (MB) or ceramic brackets (CB) were measured. METHODS: OC was applied to the bracket base, which was then placed over an attenuated total reflectance (ATR) table coupled to an infrared light spectroscope, or to a glass surface for the VHN analysis. The specimens were light-cured and DC values were calculated. The VHN was obtained in a microhardness tester. The data were analyzed with 2-way ANOVA followed by Tukey's post-hoc test (pre-set α=0.05). Linear regression analysis evaluated the relationship between RE values and dependent variables. RESULTS: CB allowed higher DC and VHN values than MB (p< 0.001). No significant difference was noted among groups when CB were used. For MB, MI groups showed the highest DC and VHN values. A significant, but weak relationship was found between delivered RE values and dependent variables. CONCLUSIONS: The decrease in RE values from third generation LED CU did not jeopardize the DC values when CB were used, but can compromise DC and VHN values when MB are used.


Asunto(s)
Luces de Curación Dental , Soportes Ortodóncicos , Cerámica , Resinas Compuestas , Dureza , Ensayo de Materiales , Polimerizacion , Cementos de Resina , Propiedades de Superficie
8.
J Clin Pediatr Dent ; 45(1): 29-34, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33690825

RESUMEN

OBJECTIVE: This study evaluated the microtensile bond strength (µTBS) of ion-releasing restorative materials to sound and caries-affected dentin (CAD). STUDY DESIGN: 60 teeth were randomly divided into 2 groups (sound dentin, CAD) and 5 subgroups of 6 samples each: conventional glass ionomer cement (GIC), resin-modified GIC (RMGIC), glass hybrid reinforced GIC (EQ), giomer (BII), and bioactive restorative material (ACT). µTBS analyses were performed and data were analyzed statistically. RESULTS: The ACT group bonded to sound dentin and the BII group bonded to CAD showed the highest µTBS (p<0.05). The GIC, RMGIC, and ACT groups, showed significantly lower µTBS when bonded to CAD compared with sound dentin (p<0.05). However, in the BII group, there were no statistically significant differences between the samples bonded to sound and CAD (p>0.05). All groups except EQ that bonded to sound dentin showed predominantly adhesive failure. CONCLUSION: The use of the giomer can be recommended due to its more stable bond durability.


Asunto(s)
Recubrimiento Dental Adhesivo , Susceptibilidad a Caries Dentarias , Dentina , Recubrimientos Dentinarios , Cementos de Ionómero Vitreo , Humanos , Ensayo de Materiales , Cementos de Resina , Resistencia a la Tracción
9.
J Prosthet Dent ; 125(4): 704.e1-704.e8, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33546855

RESUMEN

STATEMENT OF PROBLEM: If a composite resin-veneered polyetheretherketone (PEEK) restoration chips or fractures, a repair may be indicated. However, the most appropriate repair protocol for a composite resin-veneered PEEK restoration is unclear. PURPOSE: The purpose of this in vitro study was to determine the efficacy of airborne-particle abrasion and/or a primer in the repair of composite resin-veneered PEEK prostheses. MATERIAL AND METHODS: PEEK specimens (N=80) were airborne-particle abraded with alumina before being conditioned with a methyl methacrylate-based primer. A thin layer of opaquer was applied, and a split mold was then filled with a veneering resin. The specimens underwent 5000 thermocycles, and then shear bond strength (SBS) was determined and used as the positive control group. Specimens that failed in either mixed or adhesive modes were contaminated with saliva and then exposed to 4 different repair treatment methods: no airborne-particle abrasion, bonded without a primer (negative control group); airborne-particle abrasion, bonded without a primer; no airborne-particle abrasion, bonded with a primer; and airborne-particle abrasion, bonded with a primer. All specimens had opaquer applied before being veneered. Repaired specimens then underwent thermocycling before SBS testing. Data were analyzed via ANOVA with a Newman-Keuls post hoc test (α=.05). RESULTS: The SBS values for the negative control were significantly lower than those of all other repair groups and the control group (P<.018). No significant differences in the SBS values were found among these other repair groups or the positive control group (P>.05). CONCLUSIONS: Composite resin-veneered PEEK restorations or prostheses repaired with airborne-particle abrasion and/or primer can provide SBS comparable with that of the initial SBS.


Asunto(s)
Recubrimiento Dental Adhesivo , Resinas Compuestas , Materiales Dentales , Análisis del Estrés Dental , Cetonas , Ensayo de Materiales , Polietilenglicoles , Cementos de Resina , Resistencia al Corte , Propiedades de Superficie
10.
J Prosthet Dent ; 125(4): 703.e1-703.e7, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33551138

RESUMEN

STATEMENT OF PROBLEM: High-performance thermoplastics have been adopted as an alternative restorative material to metal or ceramics. However, a straightforward surface modification process to provide a durable bond strength between the polymer and the veneering material is lacking. PURPOSE: The purpose of this in vitro study was to evaluate the shear bond strength (SBS) of different veneering resin materials to polyetherketoneketone (PEKK) after different surface treatments. MATERIAL AND METHODS: Rectangular (7×7×2 mm) PEKK specimens (N=120) were randomly allocated to the following 6 groups (n=20): untreated (Cnt); nonthermal plasma (NTP) treated; tribochemical silica airborne-particle abrasion with 30-µm silica-modified Al2O3 (Tbc); abraded with a coarse-grit diamond rotary instrument (Ab); tribochemical silica airborne-particle abrasion + plasma treated (Tbc_NTP); abraded + plasma treated (Ab_NTP). After a bonding agent (PEKK Bond) was applied to the specimens, each group was divided into 2 subgroups according to the applied veneering resin materials: polymethylmethacrylate (PMMA) and nanohybrid composite resin (NHC, n=10). The specimens were stored in water for 24 hours at 37 °C and subjected to the SBS test by using a universal testing machine, and failure modes were evaluated using a stereomicroscope. Two-way analysis of variance (ANOVA) was performed followed by the Tukey honestly significant difference (HSD) test to statistically analyze the data (α=.05). RESULTS: The 2-way ANOVA showed that surface treatment methods, veneering material, and their interactions were significantly different on the SBS values (P<.001). The highest SBS values were determined for the Tbc and Tbc_NTP treatment groups not only for PMMA (10.71 to 11.63 MPa) but also for NHC (19.80 to 20.60 MPa) veneering resin materials (P<.05). CONCLUSIONS: The bonding capacity of PEKK to the PMMA and NHC veneering resin materials can be significantly improved by using tribochemical silica airborne-particle abrasion alone or with nonthermal plasma surface treatment techniques. Furthermore, using NHC veneering resin material is recommended over PMMA.


Asunto(s)
Recubrimiento Dental Adhesivo , Cementos de Resina , Óxido de Aluminio , Benzofenonas , Análisis del Estrés Dental , Ensayo de Materiales , Polímeros , Resistencia al Corte , Propiedades de Superficie , Circonio
11.
J Prosthet Dent ; 125(4): 705.e1-705.e7, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33597080

RESUMEN

STATEMENT OF PROBLEM: Dental cements that release monomers that negatively impact adjacent oral soft tissues may adversely affect clinical outcomes. However, in vitro studies evaluating the cytotoxic and genotoxic potential of substances released from dental cements are lacking. PURPOSE: The purpose of this in vitro study was to define and compare the cytotoxicity and genotoxicity of the eluates of a self-adhesive resin cement (RelyX Unicem 2 Automix) autopolymerized and light polymerized with 2 other types of luting cements: a glass ionomer cement (Ketac Cem Easymix) and a resin-modified glass ionomer cement (Ketac Cem Plus). MATERIAL AND METHODS: The eluates were prepared, and 3T3 mouse fibroblast cells were exposed for 24 hours to serial eluate dilutions of the 3 types of cement. Cytotoxicity was determined by using a cell viability assessment through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and crystal violet assays. Genotoxic effects were determined by using the cytokinesis-block micronucleus assay. RESULTS: Cell viability was higher in the presence of the glass ionomer cement eluate than of the resin-modified glass ionomer cement and resin cement eluates. A pronounced decrease in viability was found when the cells were exposed to undiluted samples of resin-modified glass ionomer cement (around 50%) or resin cement (around 80% to 90%). No significant difference in cell viability was found between autopolymerized and light-polymerized resin cements. All cements induced a dose-dependent response of mononucleated cell formation. However, only the resin cements showed double strand breaks significant differences in the deoxyribonucleic acid (DNA) molecules against the basal DNA lesions that occurred spontaneously. CONCLUSIONS: The glass ionomer cement was not found to be cytotoxic or genotoxic, whereas the eluates derived from the resin-modified glass ionomer cement and resin cement, independently of the polymerization method, were cytotoxic in fibroblast cells. Maximum cytotoxicity was observed in the presence of resin cement, which also showed genotoxicity, independently of being light polymerized.


Asunto(s)
Cementos Dentales , Cementos de Resina , Animales , Resinas Compuestas , Cementos Dentales/toxicidad , Fibroblastos , Cementos de Ionómero Vitreo/toxicidad , Ensayo de Materiales , Ratones , Cementos de Resina/toxicidad
12.
J Oral Sci ; 63(2): 139-144, 2021 Mar 31.
Artículo en Inglés | MEDLINE | ID: mdl-33597335

RESUMEN

PURPOSE: This study investigated the flexural properties, shear bond strength (SBS) and interface to dentin of three recently developed self-adhesive bulk-fill materials. METHODS: Bars of Surefil One (SO), Cention N (CN), Activa BioActive Restorative (AB) and EQUIA Forte HT Fil (EQUIA) were tested for flexural strength and flexural modulus in self-curing and light-curing modes. In addition, SBS to dentin was tested in specimens without pretreatment and after application of universal adhesive (Scotchbond Universal). EQUIA was used as the control material. RESULTS: The flexural properties were significantly better in light-curing mode for all materials except CN. CN had the highest SBS values after universal adhesive application (33.8 MPa), and SO had the highest SBS without pretreatment (20.9 MPa). CONCLUSION: The mechanical and adhesive properties of these new materials varied widely.


Asunto(s)
Recubrimiento Dental Adhesivo , Cementos de Resina , Resinas Compuestas , Cementos Dentales , Análisis del Estrés Dental , Dentina , Resistencia Flexional , Ensayo de Materiales , Resistencia al Corte , Propiedades de Superficie
13.
Bull Tokyo Dent Coll ; 62(1): 15-26, 2021 Mar 13.
Artículo en Inglés | MEDLINE | ID: mdl-33583880

RESUMEN

A range of experimental designs have been used in destructive testing of composite resin CAD/CAM crowns. Various materials have been adopted for the abutment in such tests, including human or bovine dentin, stainless steel, PMMA, and composite resin, the selection of which is made in accordance with study objective or preference of the researcher. The purpose of this study was to determine how the material selected for the abutment material affected fracture load and maximum displacement. Destructive tests were conducted on composite resin crowns of the same design. Three types of material were used for the abutments together with 2 types of adhesive material. Images of each sample were acquired before destruction using a microfocus X-ray CT scanner to confirm the feasibility of a non-destructive test.The load required to fracture the composite CAD/CAM resin crowns depended on the abutment material used, with a decrease being observed in the order of composite resin, stainless steel, and PMMA. Maximum displacement decreased in the order of PMMA, composite resin, and stainless steel. Differences in the material used for setting (adhesive resin or polycarboxylate cement) showed no effect on fracture load. These results indicate that the load required to achieve destruction of resin CAD/CAM crowns varies according to the abutment material used.


Asunto(s)
Resinas Compuestas , Diseño de Prótesis Dental , Animales , Bovinos , Coronas , Materiales Dentales , Análisis del Estrés Dental , Humanos , Ensayo de Materiales , Cementos de Resina
14.
Am J Dent ; 34(1): 31-38, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33544986

RESUMEN

PURPOSE: To examine the marginal adaptation in enamel and dentin of mixed Class V saucer shaped restorations where cavities were prepared by two different lasers. METHODS: A handpiece-integrated Er:YAG laser @ 4.5 W, 300 mJ, 15 Hz (LiteTouch III) and a novel CO2 laser @ 12.95 W, 19.3 mJ, 671 Hz (Solea 9.3 µm). Diamond bur preparation with a 25 µm diamond bur (Intensiv) in a red contra angle at high speed under water spray cooling served as the control. Eight cavities per group were readied and restored under simulation of dentin fluid with a one bottle universal adhesive (One Coat 7 Universal) and a nanohybrid resin composite (Everglow), applied in two layers. For every preparation technique, the adhesive system was applied in the selective-etch and the self-etch mode, resulting in six experimental groups. Marginal analysis was performed immediately after polishing and after simultaneous thermal (5-50°C, 2 minutes each) and mechanical (max. 49 N; 200,000 cycles) loading by using a SEM (x200 magnification). RESULTS: Significant differences were found for all groups - except groups 2 and 5 - between initial and terminal results and between the groups as well (P< 0.05, 2-way ANOVA with Fisher's post-hoc test). The bur prepared group with selective-etch technique showed the best overall results after loading, followed by Er:YAG prepared self-etch group and CO2-prepared selective-etch group. CLINICAL SIGNIFICANCE: By using a universal one-component adhesive system, marginal adaptation in enamel and in dentin depended on the preparation method and on the adhesive's application technique as well. When using lasers, Er:YAG in self-etch mode and CO2 9.3 µm in selective-etch mode total marginal adaptation showed results which were comparable to conventional bur preparation with selective-etch technique.


Asunto(s)
Recubrimiento Dental Adhesivo , Láseres de Estado Sólido , Dióxido de Carbono , Resinas Compuestas , Preparación de la Cavidad Dental , Cementos Dentales , Dentina , Recubrimientos Dentinarios , Cementos de Resina
15.
Artículo en Inglés | MEDLINE | ID: mdl-33528455

RESUMEN

The purpose of this study was to evaluate the cleaning and surface treatment techniques in the repair of aged and contaminated yttrium oxide-stabilized tetragonal polycrystalline zirconia (Y-TZP). From a total of 80 specimens of Y-TZP, 60 were subjected to aging simulation in a buccal environment with degradation in an autoclave for 24 hours (127°C/1.5 bar) and contaminated with Streptococcus mutans. The surfaces were cleaned with a triple syringe (air/water jet; n = 20) or isopropyl alcohol (n = 20), or by prophylaxis (n = 20) with pumice and water. The remaining 20 specimens comprised the control group. All specimens were then treated with silicatization (n = 10 per group) or adhesive (n = 10 per group) and repaired with composite resin. Analyses of shear strength, failure mode, and roughness were performed by electron microscopy. Data were analyzed by two-way analysis of variance (ANOVA) and t test (α = .05). Statistical significance was set at P < .05. Two-way ANOVA was significant for aging and surface treatments (P = .049), but was not significant for surface cleaning (P = .05). ANOVA results were statistically significant for surface treatments (P < .0001), with higher resistance for the silicatization groups. The failure mode was mostly adhesive for all specimens. The roughness was not significant for aging and control groups (P > .05). Triple-syringe and prophylaxis cleansing followed by silicatization was the most efficient treatment for the repair of aged and contaminated Y-TZP. There is reduced repair efficiency with the aging of Y-TZP.


Asunto(s)
Resinas Compuestas , Recubrimiento Dental Adhesivo , Anciano , Protocolos Clínicos , Análisis del Estrés Dental , Humanos , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Cementos de Resina , Resistencia al Corte , Propiedades de Superficie , Itrio , Circonio
16.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 56(2): 216-220, 2021 Feb 09.
Artículo en Chino | MEDLINE | ID: mdl-33557510

RESUMEN

Resin cements have been widely employed for bonding all-ceramic restorations in clinical practice, its color stability is directly related to long-term prosthetic effect of restorations. Discoloration of resin cements can be attributed to two causes: endogenous factors are generally related to material compositions and initiation mechanism of polymerization; exogenous factors are mainly related to stimulation of local oral environment. Color stability of resin cements has close relationship with esthetic effect of all-ceramic restorations. The aim of this literature review was to make a presentation and discussion systematically about color stability of resin cements commonly used clinically, its influence factors and influence on all-ceramic restorations, so as to provide a reference for the application of all-ceramic restorations.


Asunto(s)
Porcelana Dental , Cementos de Resina , Cerámica , Color , Estética Dental , Ensayo de Materiales
17.
Niger J Clin Pract ; 24(2): 282-291, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33605921

RESUMEN

Aims: To evaluate the effect of various aging periods and different surface preparation methods on microtensile bond strength (µTBS) for composite repair. Materials and Methods: One hundred twelve composite resin blocks were formed using a nanohybrid composite resin. The samples were distributed into four groups according to surface preparation methods (n = 28): control (sound composite blocks); Er, Cr: YSGG laser; air abrasion; silicone carbide. All samples were then divided into four subgroups according to various aging periods: (i) No aging, (ii) 10,000 thermocycling, (iii) 30,000 thermocycling, and (iv) 50,000 thermocycling. Following surface preparation and aging procedures, surface topography of one sample from each group was evaluated under scanning electron microscope (SEM). The repair composites were bonded to the sample surfaces, using a three-step etch&rinse adhesive. Finally, thirty beams of size 1 × 1 × 8 mm from each group were subjected to µTBS test and failure modes were determined. The data were analyzed using two-way ANOVA, Post-hoc Bonferroni, and Chi-square tests (P = 0.05). Results: When different surface preparation methods were evaluated together, no aging and 10,000 thermocycling groups displayed higher µTBS values (P < 0.05). When all aging periods were evaluated together, the surface preparation with air abrasion provided higher µTBS (P < 0.05). The interactions of various aging periods with different surface preparation methods revealed significant variations in repair µTBS (P < 0.05). There were statistically significant differences on failure mode distributions among surface preparation methods (P < 0.001). SEM evaluations provided valuable outcomes that help to comment on the µTBS findings. Conclusions: Different surface preparation methods, various aging periods, and the interaction of both affected the repair µTBS of the tested nanohybrid composite resin.


Asunto(s)
Recubrimiento Dental Adhesivo , Láseres de Estado Sólido , Adhesivos , Resinas Compuestas , Análisis del Estrés Dental , Humanos , Ensayo de Materiales , Cementos de Resina , Propiedades de Superficie , Resistencia a la Tracción
19.
Int J Paediatr Dent ; 31(1): 122-130, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33405356

RESUMEN

BACKGROUND: Due to the chemical and morphological differences between primary vs. permanent teeth, the time reduction of the acid etching or acidic primer can result in higher values of bond strength. AIM: To assess through a systematic review and meta-analysis the influence of the reducing etching (acid etching or acidic primer) time on the bond strength of adhesive systems to primary dentin. DESIGN: A systematic search was carried out in 3 databases: PubMed, Web of Science and Scopus. Studies that evaluated the effect of reducing the etching time on the bond strength of adhesive systems to primary dentin were included. Meta-analyses were performed using a random-effects model, with subgroups for etch-and-rinse and self-etching adhesives, with a significance level of P < .05. The risk of bias and heterogeneity between studies (Cochrane and I2 tests) were assessed. RESULTS: Eight studies were included in the systematic review and seven in the meta-analyses. The shortening etching time did not influence the immediate dentin bond strength for etch-and-rinse (Z = 0.07, P = .95) and self-etching adhesives (Z = 0.41, P = .69). After ageing, however, the shorting etching time improved the bond strength for etch-and-rinse adhesives (Z = 2.01, P = .04). All studies presented high bias risk. CONCLUSIONS: Reducing the acid-etching time to primary dentin improves the long-term bond strength to this substrate.


Asunto(s)
Recubrimiento Dental Adhesivo , Recubrimientos Dentinarios , Grabado Ácido Dental , Cementos Dentales , Dentina , Humanos , Ensayo de Materiales , Cementos de Resina , Diente Primario
20.
J Prosthet Dent ; 125(4): 674.e1-674.e7, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33431176

RESUMEN

STATEMENT OF PROBLEM: Light transmitted deep into the root canal is an important parameter to increase bonding of the cement to the post and dentin. Glass fiber posts seem to be an option to increase transmitted light, but literature on the light transmittance profile and power transmission to deep canal regions is lacking. PURPOSE: The purpose of this in vitro study was to evaluate light delivered by 2 types of fiberglass posts submitted to different surface treatments and to evaluate the bond strength. MATERIAL AND METHODS: Whiteposts and Superposts were allocated to 4 groups: no surface treatment, surface treatment with 24% hydrogen peroxide, surface treatment with silane, and surface treatment with 24% hydrogen peroxide plus silane. The total light transmitted by the posts was measured by using an integrating sphere to collect the diffuse light. The light profile that was laterally delivered to the post was measured with a power detector equipped with an optical fiber probe. The bond strength was measured with the push-out test. Scanning electron microscopy was used to evaluate the surface treatments. The light transmission data were analyzed by using a generalized linear model and the Bonferroni test and the bond strength values were evaluated by using ANOVA and the Tukey test (α=.05). RESULTS: The cervical third presented the highest transmission (74.1% for Whiteposts and 74.6% for Superposts), followed by the middle (20.9% for Whiteposts and 20.4% for Superposts) and apical (5.0% for both Whiteposts and Superposts) thirds. Superposts led to higher bond strength than Whiteposts (9.73 ±5.89 and 8.48 ±4.99 MPa, respectively). Surface treatment with silane and hydrogen peroxide plus silane afforded similar bond strength (11.4 ±6.4 and 10.7 ±5.6 MPa, respectively), which was higher as compared with the bond strength obtained after surface treatment with hydrogen peroxide. For both post types, the bond strength decreased from the cervical (12.2 ±6.0 MPa) to the middle (9.7 ±5.0 MPa) and apical (6.5 ±3.6 MPa) thirds. CONCLUSIONS: Light transmission and bond strength decreased from the cervical to the apical third. Surface treatment impacted bond strength; light transmission through Whiteposts was slightly higher than light transmission through Superposts.


Asunto(s)
Recubrimiento Dental Adhesivo , Técnica de Perno Muñón , Dentina , Vidrio , Ensayo de Materiales , Cementos de Resina
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