Veneering Resin Composites Research Articles

Effects of tetrabutylammonium dihydrogen trifluoride etchant on bond strengths of resin composites with Ti-6Al-4V and Co-Cr alloys.

This study aimed at evaluating the effects of surface treatments with tetrabutylammonium dihydrogen trifluoride (TDTF) on the bond strengths of indirect resin composites with titanium-aluminum-vanadium (Ti-6Al-4V) and cobalt-chromium (Co-Cr) alloys. Disk-shaped Ti-6Al-4V and Co-Cr alloy specimens were air-abraded with alumina, treated with an etchant (MEP) containing TDTF for 10 s (MEP10) or 30 s (MEP30), and rinsed with water. Subsequently, a primer containing 6-methacryloyloxyhexyl phosphonoacetate was applied to the surfaces, and the specimens were veneered with a light-curing indirect resin composite. Specimens without MEP were prepared as controls (no-MEP). Shear bond strengths were determined before or after 100,000 thermocycles, and the data were analyzed using the Steel-Dwass test (α = 0.05, n = 10). No significant difference was found in the bond strengths between the Ti-6Al-4V and Co-Cr alloys. In each metal alloy, the MEP10 and MEP30 specimens exhibited higher bond strengths than the no-MEP controls after 100,000 thermocycles. Scanning electron microscopy observations revealed that submicron-pits and crevices were formed on both the metal alloys upon applying the MEP etchant. Surface treatments with TDTF following air abrasion are useful for improving bonding durability while veneering resin composites on Ti-6Al-4V or Co-Cr alloy frameworks.

Impact of polymerization and storage on the degree of conversion and mechanical properties of veneering resin composites.

To investigate the degree of conversion (DC), Martens hardness (HM), elastic indentation modulus (EIT), and flexural strength (FS) of veneering resin composites (SR Nexco Paste (NP), Ceramage Incisal (CI), Gradia Plus (GP); n=60/group) cured with different polymerization devices (bre.Lux Power Unit, Labolight DUO, Otoflash G171, LC-3DPrint Box, PCU LED; n=12/subgroup) after storage. Otoflash G171 and Labolight DUO showed increased DC/HM/EIT. CI presented the lowest DC and highest HM/EIT. NP showed the highest DC and lowest HM/EIT. Within Otoflash G171, Laboligth DUO and PCU LED, highest FS was observed for CI. Storage did not affect DC/HM/EIT for specimens cured with Otoflash G171 or Labolight DUO. With storage not showing an influence on the tested parameters for polymerization devices that otherwise presented superior results, increased storage time cannot be recommended. For the tested resin composites, this study observed a high/low degree of conversion to coincide with respectively low/high amounts of fillers/mechanical properties.

Mechanical and optical properties of indirect veneering resin composites after different aging regimes.

This study tested and compared properties of six modern indirect veneering resin composites (VRC), namely Ceramage (Shofu), dialog Vario (Schütz Dental), Gradia Plus (GC Europe), in:joy (Dentsply), Signum composite (Heraeus Kulzer), and SR Nexco (Ivoclar Vivadent). Specimens were fabricated from dentin and enamel pastes and following properties were analyzed: (1) two-body wear (TB), (2) surface roughness (SR), (3) Martens hardness parameters (HM and EIT), and (4) translucency (T). The highest impact on HM and EIT was exerted by VRC brand (HM: ηP2=0.960/ EIT: ηP2=0.968; p<0.001), followed by VRC paste material (HM: ηP2=0.502/ EIT: ηP2=0.580; p<0.001), and aging duration (HM: ηP2=0.157/ EIT: ηP2=0.112; p<0.001). Lowest and highest TB were measured for Signum composite and dialog Vario, respectively (p<0.001). Highest T was showed Signum composite and Ceramage (p<0.001). VRCs should be individually selected with respect to the indication area, due to different surface properties.

Clinical Survival of Indirect, Anterior Surface-Retained Fiber-Reinforced Composite Fixed Dental Prosthesis: Up to 3-Year Follow-up.

This study evaluated the performance of indirect, anterior, surface-retained, fiber-reinforced-composite restorations (ISFRCR). Between September-2011 and September-2012, 17 patients (13 females, 4 males, mean age: 40.5) received 17 indirect ISFRCRs (maxilla=4; mandible=13). All restorations were made on a plaster model using unidirectional E-glass fibers (Interlig, Angelus) in combination with a veneering resin composite (Gradia, GC) and cemented adhesively (Choice 2, Bisco). No cavity preparations were made on the abutmentteeth. Before cementation, enamel surfaces were cleaned with pumice and etched with 38% H3PO4 for 30 s, rinsed 30 s. Then, adhesive resin was applied accordingly. Patients were followed every 3 months until May 2014. The evaluation protocol involved technical (chipping, debonding or fracture of tooth/restoration) and biological failures (caries). Survival (Kaplan Meier) and annual failure rates were calculated. Mean observation time was 34.6 months. Altogether, 5 failures were observed [survival rate: 70.5%] of which 3 were debondings and 2 delaminations of the veneering composite (chipping). All defective restorations were repaired or recemented, except one, which was remade.

Bonding of composite resins to PEEK: the influence of adhesive systems and air-abrasion parameters.

The objective of the study was to investigate the tensile bond strength (TBS) to polyaryletheretherketone (PEEK) after different pretreatment and conditioning methods. Four hundred PEEK specimens were fabricated and allocated to the following air-abrasion methods (n 1=80/pretreatment): (i) 50μm Al2O3 (0.05MPa); (ii) 50μm Al2O3 (0.35MPa); (iii) 110μm Al2O3 (0.05MPa); (iv) 110μm Al2O3 (0.35MPa); and (v) Rocatec 110μm (0.28MPa). These pretreatments were combined with the following conditioning methods (n 2=20/pretreatment/conditioning): (a) visio.link (VL); (b) Monobond Plus/Heliobond (MH); (c) Scotchbond Universal (SU); and (d) dialog bonding fluid (DB). After veneering of all specimens with dialog occlusal and aging (28days H2O, 37°C+20,000 thermal cycles, 5/55°C), TBS was measured. Data was analysed using Kaplan-Meier survival analysis with Breslow-Gehan test and Cox-regressions. The major impact on TBS showed the conditioning, followed by the air-abrasion-pressure, while the grain size of the air-abrasion powder did not show any effect. Specimens air-abraded at 0.35MPa showed the highest survival rates. However, within VL groups, this observation was not statistically significant. Within MH groups, pretreatment using 110μm Al2O3 and 0.05MPa resulted in higher survival rates compared to groups treated with 50 and 110μm Al2O3 using a pressure of 0.35 MPa. The use of VL showed the highest survival rates between the adhesive systems and the TBS values higher than 25MPa independent of the pretreatment method. As an exception, only VL showed significantly higher survival rates when compared to MH. The adequate choice of the adhesive system and higher pressures improved the TBS between PEEK and veneering resin composite. The particle size had no major impact. According to this study, best veneering of PEEK with dialog occlusal can be achieved by conditioning with visio.link in combination with the pretreatment of airborne particle abrasion at a pressure of 0.35MPa.

Retention strength between veneering resin composites and laser-sintered cobalt-chromium alloy.

The purpose of the present study was to evaluate the retention strength between a resin composite veneering material and three types of cobalt-chromium (Co-Cr) alloy substrates. Co-Cr alloy specimens with 81 retention devices (LSR), with 144 retention devices (LDR), and without retention device (LN) were fabricated using a laser-sintering system. The specimens were air-abraded with alumina, conditioned with a primer [Alloy primer (AP) or M.L. primer (ML)], and veneered with a light-polymerized resin composite (Gradia). Three control groups (LSR-N, LDR-N, and LN-N) without primer were also prepared. After 20,000 thermocycles in 4 and 60°C water, tensile retention strengths were determined using a universal testing machine. Data were analyzed by analysis of variance and a post hoc Tukey-Kramer HSD test (α=0.05, n=8). The highest retention strengths were obtained in LSR-AP (28.3MPa), LSR-ML (23.3MPa), LDR-AP (26.9MPa), and LDR-ML (27.8MPa), and these values were not significantly different. In the absence of a retention device, the retention strengths were significantly different in the following order: LN-N (0.1MPa)<LN-ML (12.4MPa)<LN-AP (20.2MPa). The specimens without primer were significantly different in the following order: LN-N (0.1MPa)<LSR-N (15.4MPa), LDR-N (17.1MPa). No significant difference was found between the numbers of retention devices, which were 81 and 144. In conclusion, the combined use of the primers and the retention devices is recommended when the laser-sintered Co-Cr alloy is veneered with the resin composite materials to maximize the retention strength.

Shear Bond Strength between Fiber‐Reinforced Composite and Veneering Resin Composites with Various Adhesive Resin Systems

The aim of this research was to evaluate the shear bond strength of different laboratory resin composites bonded to a fiber-reinforced composite substrate with some intermediate adhesive resins. Mounted test specimens of a bidirectional continuous fiber-reinforced substrate (StickNet) were randomly assigned to three equal groups. Three types of commercially available veneering resin composites - BelleGlass®, Sinfony®, and GC Gradia® were bonded to these specimens using four different adhesive resins. Half the specimens per group were stored for 24 hours; the remaining were stored for 30 days. There were 10 specimens in the test group (n). The shear bond strengths were calculated and expressed in MPa. Data were analyzed statistically, and variations in bond strength within each group were additionally evaluated by calculating the Weibull modulus. Shear bond values of those composites are influenced by the different bonding resins and different indirect composites. There was a significant difference in the shear bond strengths using different types of adhesive resins (p = 0.02) and using different veneering composites (p < 0.01). Belle-Glass® had the highest mean shear bond strength when bonded to StickNet substrate using both Prime & Bond NT and OptiBond Solo Plus. Sinfony® composite resin exhibited the lowest shear bond strength values when used with the same adhesive resins. The adhesive mode of failure was higher than cohesive with all laboratory composite resins bonded to the StickNet substructure at both storage times. Water storage had a tendency to lower the bond strengths of all laboratory composites, although the statistical differences were not significant. Within the limitations of this study, it was found that bonding of the veneering composite to bidirectional continuous fiber-reinforced substrate is influenced by the brand of the adhesive resin and veneering composite.

Influence of PEEK surface modification on surface properties and bond strength to veneering resin composites.

To test the impact of mechanical and chemical treatments of PEEK on surface roughness (SR), surface free energy (SFE), and tensile bond strength (TBS) to veneering resin composites. PEEK specimens (N = 680) were fabricated and divided into treatment groups (n = 170/group): 1. air abrasion (AIA); 2. etching with piranha solution (PIS); 3. air abrasion + piranha acid etching (AIP); and 4. no treatment (NO). Ten specimens of each treatment group were assessed with a contact angle measuring device and profilometer to determine SFE and SR, respectively. The remaining 160 specimens of each group were divided into subgroups according to coupling method (n = 32/subgroup): 1. Monobond Plus/ Heliobond (MH); 2. Visio.link (VL); 3. Clearfil Ceramic Primer (CCP); 4. Signum PEEK Bond (SPB); and 5. control, no coupling (CG). Specimens were veneered using Signum Composite/SiCo or Signum Ceramis/SiCe (both: n = 16), incubated in water (60 days at 37°C) and thermocycled (5000 cycles of 5°C/55°C). TBS was measured and data analyzed by three- and one-way ANOVA, Kruskal-Wallis and Mann-Whitney tests (p < 0.05). A significant effect of surface treatment (p < 0.001) and coupling agent application (p < 0.001) on TBS was observed. AIA specimens with/without PIS showed the highest SFE, SR, and TBS. No differences were measured between PIS and NO, and between AIA and AIP. When no coupling agent was used, no adhesion was obtained. CCP resulted in low adhesion values, whereas MH, SPB, and VL exhibited increased TBS. No significant impact of the veneering resin composite on TBS was found (p = 0.424). AIA and AIP combined with VL, SPB, and MH can be recommended for clinical use.

Effects of a fluoride etchant and a phosphate primer on bonding of veneering composite to Ti–6Al–4V alloy for CAD/CAM restorations

PurposeTitanium abutments and superstructures are commonly veneered or covered with esthetic materials. The present investigation was carried out to evaluate the effects of an experimental surface treatment using etchant and primer on bond strength between a resin composite and Ti–6Al–4V alloy. MethodsDisk-shaped Ti–6Al–4V alloy was machine milled, the surface was air abraded with alumina, and the alloy was chemically etched with 5wt% ammonium hydrogen fluoride (F-etch) for 30s. A phosphate primer (MDP-primer) was applied to the bonding area, and then a resin composite, with or without milled-fiber resin composite (FRC), was veneered on the specimen. Shear bond strengths were determined after thermocycling for 20,000 cycles. Bond strength data were analyzed by means of ANOVA and a multiple comparison test (α=0.05). The surface of Ti–6Al–4V alloy was observed using a scanning electron microscope before and after the etching procedure. ResultsNo-FRC/F-etch/MDP-primer exhibited the highest bond strength (28.2MPa), followed by No-FRC/No-etching/MDP-primer (24.2MPa), FRC/F-etch/MDP-primer (19.9MPa), FRC/No-etching/MDP-primer (17.8MPa), No-FRC/No-etching/No-primer (13.6MPa), while FRC/No-etching/No-primer (2.5MPa) resulted in the lowest value. Microphotographs showed that numerous micro and nano pits were created on the Ti–6Al–4V alloy surface modified with F-etch. ConclusionsThe bond strength between Ti–6Al–4V alloy and the veneering resin composite was the highest when the alloy surface was modified with alumina blasting, fluoride etchant, and phosphate primer successively.

Silica film coating method for veneering resin composite

The preceramic polymer perhydropolysilazane (PHPS) is an attractive candidate as a coating material to prevent discoloration of veneering resin composites. At the present time, however, a practical method to apply this material is not available. The purpose of this study was to establish a low-temperature method for applying a silica film coating to a veneering resin composite. Two types of PHPS, NP and NL, were coated onto a veneering resin composite. The specimens were exposed to hydrogen peroxide vapor at 97°C, and the state of the conversion process was evaluated using FT-IR. With exposure to the hydrogen peroxide vapor, a 0.5-µm-thick silica film similar to that produced by baking was formed on the surface of the NP samples in 10 min, while a 0.2-µm-thick film was formed on the NL in 15 min. The silica coating method described in this study may mitigate the discoloration of veneering resin composite.

Interpenetrating Polymer Networks (IPNs) in Dental Polymers and Composites

An interpenetrating polymer network (IPN) is a material containing two polymers, each in network form. In biomaterials used in dentistry, the IPN-like nanostructures are used in denture base polymers, denture teeth and fibre-reinforced composites. IPN structures provide the specific and desired properties for the resin system prior to and after polymerization. At adhesive interfaces, IPN polymers and composites provide good interfacial adhesion for adhering and veneering resin composites based on the so-called secondary-IPN bonding formation due to swelling of the IPN nanostructure. Good interfacial adhesion is a requirement for the success of modern adhesive dentistry.

Shear bond strength of veneering composite resin to titanium nitride coating alloy deposited by radiofrequency sputtering

The success of dental restorations utilizing composite resin over cast alloy has been variable and affected by micro-leakage. The purpose of this study was to investigate the shear bond strength between a composite resin and cast dental alloy coated with a layer of titanium nitride (TiN). Cast disk specimens made of Au-Pd-Ag alloy were randomly divided into four groups. The first group was left uncoated as a control while one group was coated with a metal conditioner, and the other two were coated with TiN at either 200 or 500 W with a radiofrequency magnetron sputtering system. Each group was then bonded to one of two types of light-activated composite resin material. Shear bond strengths were tested and compared for each specimen. The bond strength of each group was analyzed by 2-way ANOVA and by post hoc multiple comparison tests (Fisher's PLSD). As the interaction among groups was not significant (p=0.27) by 2-way ANOVA, TiN coated groups were found to have improved shear bond strength compared with non-coated groups without metal conditioner for both resin composite materials by multiple comparison tests. Furthermore, TiN coating is significantly stronger than non-coated groups with metal conditioner for one of the two resin composite materials examined (p<0.01). The results suggested that metal surface modification by coated TiN represents a technique that may significantly improve the bond between the Au-Pd-Ag alloy and veneering resin composite.