Sodium hypochlorite effects on dentin bond strength and acid-base resistant zone formation by adhesive systems

Aim: To evaluate the effects of 10% NaOCl gel application on the dentin bond strengths and morphology of resin-dentin interfaces formed by three adhesives. Methods: Two etch-and-rinseadhesives (One-Step Plus, Bisco Inc. and Clearfil Photo Bond, Kuraray Noritake Dental) and oneself-etch adhesive (Clearfil SE Bond, Kuraray Noritake Dental) were applied on dentin accordingto the manufacturers’ instructions or after the treatment with 10% NaOCl (ED-Gel, Kuraray NoritakeDental) for 60 s. For interfacial analysis, specimens were subjected to acid-base challenge andobserved by SEM to identify the formation of the acid-base resistant zone (ABRZ). For microtensilebond strength, the same groups were investigated and the restored teeth were thermocycled(5,000 cycles) or not before testing. Bond strength data were subjected to two-way ANOVA andTukey’s test (p<0.05). Results: NaOCl application affected the bond strengths for One-Step Plusand Clearfil Photo Bond. Thermocycling reduced the bond strengths for Clearfil Photo Bond andClearfil SE Bond when used after NaOCl application and One-Step Plus when used asrecommended by manufacturer. ABRZ was observed adjacent to the hybrid layer for self-etchprimer. The etch-and-rinse systems showed external lesions after acid-base challenge and noABRZ formation when applied according to manufacturer’s instructions. Conclusions:10% NaOClchanged the morphology of the bonding interfaces and its use with etch-&-rinse adhesives reducedthe dentin bond strength. Formation of ABRZ was material-dependent and the interface morphologieswere different among the tested materials.

Efeito de cerâmicas odontológicas na passagem da luz emitida por aparelhos fotoativadores / Effect of dental ceramics on the transmittance of light emitted by curing units

Este estudo avaliou a influência de dois tipos de cerâmicas odontológicas (óxido de zircônio e dissilicato de lítio) na transmitância da luz emitida por diferentes aparelhos fotoativadores. Discos com 1 mm de espessura e 10 mm de diâmetro foram preparados a partir dos materiais restauradores indiretos: IPS e.Max Zircad (lvoclar Vivadent) e IPS e.Max (lvoclar Vivadent). Sobre os materiais protéticos foi aplicada a cerâmica à base de nanofluorapatita (IPS e.Max Ceram, Ivociar vivadent), com 1 mm de espessura. Cinco diferentes aparelhos fotoativadores foram testados: Arc Light 11 (AirTechniques), ColtoLux LED (Colténe Whaledent), Elipar Free Light 2 (3M ESPE), Astralis 10 (lvoclar Vivadent) e Ultralume 5 (Ultradent), sendo esse último utilizado no modo normal, apenas com luz azul ou luz violeta. A irradiância através dos diferentes materiais restauradores foi mensurada com um espectroradiômetro (DAS 2100, Labsphere) associado a um software especifico (Spectra Suite, Ocean Optics). Os dados foram submetidos à analise de variância de 2 fatores e teste de T ukey (p:s;O,05). A luz emitida pelo aparelho arco de plasma (Arc Light 11) mostrou maior passagem através dos materiais indiretos estudados, enquanto a luz violeta emitida pelo aparelho Ultralume 5 foi a mais bloqueada entre os aparelhos. A zircônia permitiu maior passagem de luz quando comparada ao dissilicato de lítio. Os materiais restauradores indiretos estudados apresentaram comportamentos distintos com relação à passagem de luz. O tipo de aparelho fotoativador influenciou a irradiância através dos diferentes materiais restauradores.

This study evaluated the influence of different types of restorative indirect materiais (zirconium oxide and lithium disilicate) in transmittance of light emitted by different types of curing units. Discs with 1 mm thickness and 10 mm dia meter were prepared from the indirect restorative materiais: IPS e.max ZirCAD (Ivoclar Vivadent) and IPS e.max (Ivoclar Vivadent). A nanofluorapatite ceramic (IPS e.max, Ivoclar Vivadent) was applied over theindirect materiais with 1 mm thickness. Five different light curing units were tested: Arc Light II (Air Technologies), ColtoLux LED (Colténe Whaledent), Elipar Free Light 2 (3M ESPE), Astralis 10 (Ivoclar Vivadent) and Ultralume 5 (Ultradent), which was used in regular mode, only light blue and only violet. The Irradiance through different restorative materiais was measured using a spectroradiometer (DAS 2100, Labsphere) associated with a specific software (Spectra Suite, Ocean Optics). Data were analyzed by two-way analysis of variance and Tukey test (p:s;O,05). The plasma are curing unit (Arc Light 11) showed the highest irradiance values through different restorative materiais, while the light source Ultralume 5, violet mode, showed the lowest irradiance values through different restorative materiais. The zirconia allowed higher light intensity passed through it when compared to lithium disilicate. The indirect restorative materiais tested showed distinct properties regarding the transmittance of light. Type of curing unit significantly influenced the Irradiance through different restorative materiais.

Influence of viscosity and curing mode on degree of conversion of dual-cured resin cements.

OBJECTIVE: The purpose of this study was to evaluate the effects of the viscosities and curing modes on the degree of conversion (DC) of two resin cements. METHODS: Eight experimental groups were evaluated (n=5), according to the dual-cured resin cements (Nexus 2/Variolink II), viscosity (low and high) and evaluation time (5 minutes and 24 hours). The resin cements were applied to surface of a horizontal attenuated-total-reflectance unit and were polymerized either with self-cure (SC) or light exposure (XL3000/3M ESPE) for 40 seconds. Infrared spectra were obtained after 5 minutes and 24 hours (Nicolet 520 FT-IR/Thermo Scientific Inc.). DC was calculated according to changes in aliphatic-to-aromatic peak ratios pre- and post-curing. Data (%) were analyzed by 3-way repeated measure ANOVA (curing mode, viscosity and time interval) and Tukey's post-hoc test (P<.05). RESULTS: The dual-polymerizing mode provided higher DC than auto-polymerization. The DC mean values increased for both resin cements after 24 hours. The low-viscosity resin cements from light-activated or self-cured groups exhibited higher DC than high viscosity version. CONCLUSION: The DC of resin cements was higher for the low viscosity version, following the light-polymerization and when were tested after 24 hours.

Avaliação da resistência de união adesivo-dentina - Efeito do armazenamento em saliva artificial / Bond strength evaluation of adhesive-dentin - Effect of artificial saliva storage

Introdução - Os sistemas adesivos têm evoluído e a durabilidade da união resina-dentina é um assunto importante na Odontologia Restauradora, uma vez que está diretamente relacionada com a longevidade dos procedimentos restauradores. Este estudo avaliou o efeito do tempo de armazenamento em saliva artificial na resistência de união de 4 adesivos à dentina. Material e Métodos - Vinte terceiros molares foram utilizados e divididos em 4 grupos (n=5), que corresponderam aos adesivos testados: Adper Easy Bond (EB), AdperSE Plus (SP), Adper Single Bond 2 (SB) e Clearfil SE Bond (CS). Os adesivos foram aplicados na dentina oclusal planificada e em seguida, os dentes foram restaurados com incrementos de 2 mm de resina composta. Após armazenamento em água destilada por 24 horas, os dentes restaurados foram seccionados seguindo a metodologia de microtração. Metade dos espécimes obtidos de cada dente foi armazenada em saliva artificial a 37°C por 6 meses (6ME) e a outra metade (24H) submetida ao teste de microtração. Os dados foram analisados pela ANOVA (2 fatores) e teste de Tukey (p<0,05). Resultados - Os adesivos produziram similar resistência de união à dentina nos dois tempos avaliados (p=0,7860). A resistência de união de união dos adesivos não apresentou diferença significativa entre os tempos avaliados (p=0,8454). As médias de resistência de união (DP) para os adesivos foram (MPa): EB(24H): 57,8(17,4), EB(6ME): 57,7(18,5), SP(24H): 57,9(15,5), SP(6ME): 55,9(9,6), SB(24H): 48,9(8,1), SB(6ME): 49,7(7,9), CS(24H): 60,1(21,0) e CS(6ME): 59,0(9,5). Conclusão - A resistência da união adesivo-dentina não foi afetada pelo tempo do armazenamento.

Introduction – The adhesive systems have improved and the resin-dentin bond durability is an important subject within Restorative Dentistry, since it is related to longevity of composite restorations. This study evaluated the effect of artificial saliva storage on bond strength of 4 adhesives to dentin. Material and Methods - Twenty third molars were used in this study. They were divided into 4 groups (n=5), which corresponded to adhesives tested: Adper Easy Bond (EB), Adper SE Plus (SP), Adper Single Bond 2 (SB) and Clearfil SE Bond (CS). Bonding agents were applied to flat oclusal dentin surface and the teethwere incrementally restored with composite resin. After 24 hours of water storage, the restored teeth were sectioned according to the micro-tensile bond methodology. The half of bonded beam specimens were stored in artificial saliva at 37 oC for 6 months (6ME) andthe other half (24H) was tested in tension. Data were analyzed by two-way ANOVA and Tukey test (p<0.05). Results - The results suggested that the adhesives present similar bond strength mean values to dentin in both evaluation times. (p=0.7860). The bond strengthof adhesive systems was not different between the evaluation times (p=0.8454). The bond strength means (DP) for the adhesives were (MPa): EB(24H): 57.8(17.4), EB(6ME): 57.7(18.5), SP(24H): 57.9(15.5), SP(6ME): 55.9(9.6), SB(24H): 48.9(8.1), SB(6ME): 49.7(7.9), CS(24H): 60.1(21.0) and CS(6ME): 59.0(9.5). Conclusion - The resin-dentinbond strength of the adhesives tested was not affect by storage.

Adhesive bonding of resin cements to cast titanium with adhesive primers.

The purpose of this study was to evaluate the effects of adhesive primer applications on the bond strength of resin cements to cast titanium. Four adhesive primers - Metaltite, Metal Primer II, Alloy Primer and Ceramic Primer - and their respective resin cements - Bistite II DC, Link Max, Panavia F 2.0, RelyX Unicem and RelyX ARC - were tested. Cast plates were prepared from titanium ingots (n=6 specimens/cement) and had their surfaces airborne-particle abraded with Al2O3 (50 µ m). Three resin cement cylinders were built on each bonded titanium surface, using a cylindrical translucent tubing mold and were subjected to micro-shear testing. Data were analyzed statistically by two-way ANOVA and Tukey's post-hoc test (α=0.05). The application of Metal Primer II and Ceramic Primer resulted in significant higher bond strength for Link Max and RelyX Unicem resin cements, respectively, than nonuse of adhesive primers. Panavia F 2.0 and RelyX ARC yielded high bond strength means with or without adhesive primers. The use of adhesive primers might increase the bond strength to cast titanium depending on the resin cement used.

Influence of viscosity and polymerization mode on bond strength of dual-curing resin luting agent to dentin

Aim: To evaluate the influence of the viscosity and curing mode on the bond strength of two resincements to dentin. Methods: Eight experimental groups were formed (n = 7) according to thedual-cure resin cements (Nexus 2 - Kerr Corp. and Variolink II - Ivoclar Vivadent), curing modes(dual-cure or self-cure) and viscosities (low and high). Resin cements were applied to pre-curedcomposite resin discs (2 mm thick, Sinfony -3M ESPE), which were fixed to bonded dentinsurfaces. The restored teeth were either light-activated (XL3000 - 3M ESPE) or allowed to selfcuring only. After 24 h, the teeth were both mesiodistally and buccolingually sectioned to obtainbonded beam specimens (0.8 mm2 cross-sectional area). Each specimen was tested in microtensilestrength at a crosshead speed of 0.5 mm/min until failure. Results: Data (in MPa) were analyzedstatistically by three-way ANOVA and Tukey’s post-hoc test (pre-set á = 0.05). No significantdifference was observed between resin cements (p=0.26) and viscosities (p=0.13), however, thecuring mode affected the BS within the viscosities (p=0.01). Statistically significant difference wasobserved for low viscosity: Nexus 2: 23.8(10.6) (dual-cure) and 16.0(5.1) (self-cure); VariolinkII: 28.7(8.7) (dual-cure) and 11.9(3.0) (self-cure). Conclusions: Light activation yielded higherbond strength for the low-viscosity versions of the resin cements.

Inorganic composition and filler particles morphology of conventional and self-adhesive resin cements by SEM/EDX.

The purpose of this study was to characterize the inorganic components and morphology of filler particles of conventional and self-adhesive, dual-curing, resin luting cements. The main components were identified by energy dispersive X-ray spectroscopy microanalysis (EDX), and filler particles were morphologically analyzed by scanning electron microscopy (SEM). Four resin cements were used in this study: two conventional resin cements (RelyX ARC/3M ESPE and Clearfil Esthetic Cement/Kuraray Medical) and two self-adhesive resin cements (RelyX Unicem/3M ESPE and Clearfil SA Luting/Kuraray Medical). The materials (n = 5) were manipulated according to manufacturers' instructions, immersed in organic solvents to eliminate the organic phase and observed under SEM/EDX. Although EDX measurements showed high amount of silicon for all cements, differences in elemental composition of materials tested were identified. RelyX ARC showed spherical and irregular particles, whereas other cements presented only irregular filler shape. In general, self-adhesive cements contained higher filler size than conventional resin luting cements. The differences in inorganic components and filler particles were observed between categories of luting material and among them. All resin cements contain silicon, however, other components varied among them.

Adhesive bonding of resin cements to cast titanium with adhesive primers

The purpose of this study was to evaluate the effects of adhesive primer applications on the bond strength of resin cements to cast titanium. Four adhesive primers - Metaltite, Metal Primer II, Alloy Primer and Ceramic Primer - and their respective resin cements - Bistite II DC, Link Max, Panavia F 2.0, RelyX Unicem and RelyX ARC - were tested. Cast plates were prepared from titanium ingots (n=6 specimens/cement) and had their surfaces airborne-particle abraded with Al2O3 (50 μ m). Three resin cement cylinders were built on each bonded titanium surface, using a cylindrical translucent tubing mold and were subjected to micro-shear testing. Data were analyzed statistically by two-way ANOVA and Tukey's post-hoc test (α=0.05). The application of Metal Primer II and Ceramic Primer resulted in significant higher bond strength for Link Max and RelyX Unicem resin cements, respectively, than nonuse of adhesive primers. Panavia F 2.0 and RelyX ARC yielded high bond strength means with or without adhesive primers. The use of adhesive primers might increase the bond strength to cast titanium depending on the resin cement used.

O objetivo deste estudo foi avaliar o efeito da aplicação de primers na resistência de união de cimentos resinosos ao titânio. Quatro primers - Metaltite, Metal Primer II, Alloy Primer and Ceramic Primer - e seus respectivos cimentos resinosos - Bistite II DC, Link Max, Panavia F 2.0, RelyX Unicem and RelyX ARC - foram testados. Placas de titânio foram preparadas a partir da fundição de lingotes (n=6 espécimes/cimento) e as superfícies dessas placas foram jateadas com partículas de Al2O3 (50 μ m). Três cilindros de cimento resinoso foram construídos em cada placa de titânio, utilizando moldes transparentes com formato de cilindro e foram submetidos ao teste de microcisalhamento. Os dados foram analisados pela ANOVA (dois fatores) e teste de Tukey (α=0,05). A aplicação do Metal Primer II e do Ceramic Primer resultou no aumento significativo da resistência de união para os cimentos resinosos Link Max e RelyX Unicem, respectivamente. Os cimentos Panavia F 2.0 e o RelyX ARC mostraram altos valores de resistência de união com ou sem o uso dos primers. A aplicação dos primers pode aumentar a resistência de união dos cimentos resinosos ao titânio, dependendo do tipo de cimento resinoso utilizado.

Influence of curing mode and time on degree of conversion of one conventional and two self-adhesive resin cements.

This study evaluated the effect of curing mode (auto- and dual-polymerizing mode) and time interval (5, 10 and 15 minutes) on the degree of conversion of resin cements. One conventional dual-cured resin cement (Panavia F 2.0 [Kuraray Medical Inc]) and two self-adhesive cements (RelyX Unicem [3M ESPE] and BisCem [BISCO, Inc]) were evaluated. The products (n = 5) were manipulated according to the manufacturer's instructions and applied to the surface of a horizontal attenuated reflectance unit attached to an infrared spectrometer. The materials were either light-cured for 40 seconds (dual-polymerizing mode) or allowed to auto-polymerize. The degree of conversion was calculated according to changes in the aliphatic-to-aromatic peak ratios prior to and 5, 10 and 15 minutes after light-activation or after mixing when the specimens were allowed to auto-polymerize. Data (%) were analyzed by two-way repeated measure ANOVA (curing mode and time interval) and Tukey's post-hoc test (alpha = 0.05%). The light-activating mode led to a higher degree of conversion values than the self-curing mode in self-adhesive cements (RelyX Unicem and BisCem), while there was no difference in the degree of conversion between the self- and light-cured groups of Panavia F 2.0 resin cement. All products showed a higher degree of conversion at 15 minutes postcuring than any other evaluation interval. The self-adhesive cements provide a higher degree of conversion values when light-activated. After 15 minutes of polymerization initiation, the degree of conversion was higher in all resin cements, regardless of the curing mode.

Bond strength of resin cements to Co-Cr and Ni-Cr metal alloys using adhesive primers.

PURPOSE: The aim of this study was to evaluate the effectiveness of adhesive primers (APs) applied to Co-Cr and Ni-Cr metal alloys on the bond strength of resin cements to alloys. MATERIALS AND METHODS: Eight cementing systems were evaluated, consisting of four resin cements (Bistite II DC, LinkMax, Panavia F 2.0, RelyX Unicem) with or without their respective APs (Metaltite, Metal Primer II, Alloy Primer, Ceramic Primer). The two types of dental alloys (Co-Cr, Ni-Cr) were cast in plate specimens (10 x 5 x 1 mm(3)) from resin patterns. After casting, the plates were sandblasted with aluminum oxide (100 microm) and randomly divided into eight groups (n = 6). Each surface to be bonded was treated with one of eight cementing systems. Three resin cement cylinders (0.5 mm high, 0.75 mm diameter) were built on each bonded metal alloy surface, using a Tygon tubing mold. After water storage for 24 hours, specimens were subjected to micro-shear testing. Data were statistically analyzed by two-way ANOVA and Tukey's studentized range test. RESULTS: The application of Metal Primer II resulted in a significantly higher bond strength for LinkMax resin cement when applied in both metal alloys. In general, the cementing systems had higher bond strengths in Co-Cr alloy than in Ni-Cr. CONCLUSIONS: The use of AP between alloy metal surfaces and resin cements did not increase the bond strength for most cementing systems evaluated.

Avaliação da resistência de união de novos sistemas adesivos ao esmalte e dentina / Enamel and dentin bond strength evaluation of new adhesive systems

O estudo avaliou a resistência de união (RU) ao esmalte e à dentina de dois novos sistemas adesivos: Tetric N-Bond (TN), que preconiza o condicionamento ácido separado e o autocondicionante Bond Force. A superfície vestibular de 24 incisivos bovinos foi desgastada para exposição do esmalte e dentina. As amostras foram alatoriamente distribuídas em quatro grupos (n=6). Três cilindros de resina composta foram obtidos por dente. Após, as amostras foram submetidas ao ensaio de microcisalhamento e as médias abalisadas estatisticamente (Anova, p<0.05). O adesivo TN apresentou valores superiores e a RU ao esmalte foi maior para os dois adesivos.