- Email: [email protected]
or biomimetic analogs
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insight for future antimicrobial, bioactivity, and osseointegration testing of implant materials. http://dx.doi.org/10.1016/j.dental.2015.08.138 P3 Curing profiles of CQ- and TPO-based composites using polywave leds D. Oliveira 1,2,∗ , M.G. Rocha 1,2 , I.C. Correa 3 , A.B. Correr 1 , J.L. Ferracane 2 , M.A.C. Sinhoreti 1 1
Piracicaba Dental School, State University of Campinas, Piracicaba, Brazil 2 School of Dentistry, Oregon Health and Science University, Portland, USA 3 School of Dentistry, Federal University of Rio De Janeiro, Rio De Janeiro, Brazil
Purpose: To evaluate the influence of beam-profile on light transmittance and curing profile of camphorquinone (CQ) and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO)based resin composites using different polywave LEDs. Methods and materials: Experimental resin-based composites were produced using the same organic matrix (10.1 wt% Bis-GMA, 11.4 wt% UDMA, 11.4 wt% Bis-EMA and 2.1 wt% TEGDMA) containing either CQ (0.2 wt%) or TPO (0.4 wt%) and 65 wt% filler (52 wt% 0.7 m BaBSiO2 and 13 wt% 0.05 m fumed silica). Class I restorations (5 × 5 mm, 3 mm depth) were performed into a custom-designed transparent polymethylmethacrylate (PMMA) mold using two polywave LEDs with 24 J/cm2 (Bluephase G2, Ivoclar Vivadent and Valo Cordless, Ultradent). Each LED was reproducibly positioned in order to establish the regions of the restoration exposed to the light emitted from the blue and violet LEDs, and the overlapping region in between. To map the degree of conversion (DC), 5 mm × 3 mm longitudinal cross-sectional specimens (0.3 mm thick) of the center of the restoration were evaluated using a FT-IR Microscope (Nicolet Continuum, Thermo Scientific) coupled to a FT-IR spectrometer (Nicolet Nexus 6700, Thermo Scientific) in the near-IR region. Light transmittance change during curing was also evaluated using a resin calibrator (MARC, BlueLight Analytics) for composites of three different thicknesses: 1 mm, 2 mm and 3 mm. Data were analyzed using ANOVA and Tukey’s test for multiple comparisons (a = 0.05; ˇ = 0.2). Results: CQ-based composite demonstrated lower initial light-transmittance before curing compared to TPO, but the highest change and highest light-transmittance after curing (p < 0.001). There were no differences in the curing profile between the light curing units tested (p = 0.89); similar effects of the different LED regions (blue, center and violet) were found (p = 0.09) (Fig. 1). Up to 1 mm in depth, no differences in the DC were found between the photo-initiators or among the different regions evaluated. Starting at the 2 mm depth, the TPO-based composite showed a decrease in cure efficiency near the blue emittance region. The CQ-based composites only showed decreased cure efficiency at the 3 mm depth in the violet emittance region.
Fig. 1
Conclusion: Composites based on CQ demonstrate higher light-transmittance than TPO-based composite. CQ- and TPO-based composites presented similar curing profiles at increments up to 1 mm thick; but at greater thicknesses, composites with TPO presented a decrease in depth of cure starting at 2 mm and CQ-based composites at 3 mm near the wavelength emittance outside their absortivity. http://dx.doi.org/10.1016/j.dental.2015.08.139 P4 Remineralization of bonded-dentin through Ca/P-releasing adhesives and/or biomimetic analogs G. Abuna 1,∗ , V.P. Feitosa 2 , S. Sauro 3 , G. Cama 4 , M. Giannini 1 , M.A. Sinhoreti 1 1
State University of Campinas, Brazil Federal University of Ceara, Brazil 3 Cardenal Herrera University, Spain 4 Ghent University, Belgium 2
Purpose: To assess the remineralization of an experimental Ca2+ /PO4 3− -releasing resin-based adhesive applied on mineral-depleted dentin pre-treated with primers doped with or without biomimetic analogs. Methods and materials: A two-step adhesive system was created by incorporating sodium trimetaphosphate (TMP) and/or polyacrylic acid (PAA) into a GDMAP-(glycerol dimethacrylate-dihydrogen-phosphate)-based primer. Equimolar amounts of beta-tri-calcium-phosphate (betaTCP) and monocalcium-phosphate-monohydrate (MCPM) were incorporated into a light-curable resin adhesive. An analogs-free primer and a filer-free adhesive were used as control. Fifty extracted human molars were prepared and divided into 5 groups (n = 10); the specimens were bonded as following: Control: analogs-free primer/filer-free adhesive; Primer + Ca/P: control primer/ion-releasing adhesive; PAA + Ca/P: PAA-containing primer/ion-releasing adhesive;
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TMP + Ca/P: TMP-containing primer/ion-releasing adhesive; TMP/PAA + Ca/P: TMP/PAA-containing primer/ion-releasing adhesive. Build-ups were made using Filtek Z350XT. Specimens were challenged under simulated pulpal pressure (SPP) for 24 h or 6 months and subsequently submitted to TBS; results were analyzed by two-way ANOVA and Tukey test (p < 0.05). Three sticks from each group were prepared for SEM nanoleakage analysis. In order to characterize the phosphate precipitation in totally demineralized in EDTA (17%), five dentin discs each group were pre-treated with the tested primers as previously described and kept in intimate contact in artificial saliva (AS) with the adhesive doped with or without ion-releasing micro-filler up to 6 months. The same specimens were then processed for Transmission Electron Microscopy (TEM) analysis to assess the intra- and/or extra-fibrilar collagen remineralization. Results: The TBS of the control group was significantly reduced after 6 months SPP (p > 0.05). Only the specimens bonded with the ion-releasing adhesive on dentin surface primed without biomimetic analogs or with both PAA and TMP showed stable TBS over time (p < 0.05). The use of PAA or STMP alone reduced the initial TBS (p > 0.05). Nanoleakage increased after SPP in the control group specimens, but reduced in the specimens treated with the ion-releasing resin. All the specimens treated with the ion-releasing adhesive showed during FTIR analysis increase of peaks at 947, 1033 and 1092 cm−1 attributed to PO4 of apatite. TEM showed nano-needles intra-fibrillar precipitation especially in the specimens treated with the ion-releasing adhesive in presence of both the biomimetic analogs. Conclusion: The experiment Ca/PO-releasing adhesive evokes intra-fibrillar dentin collagen and prevents degradation of resin–dentin interfaces particularly when used in combination with a primer containing both the biomimetic analogs (TMP and PAA). However, stable bond strength can be achieved after 6-month storage under SPP also when the Ca/PO-releasing resin is used in combination with the GDMAPbased primer.
http://dx.doi.org/10.1016/j.dental.2015.08.140
P5 Synergism of CQ-amine and TPO in experimental resin composites M.G. Rocha 1,2,∗ , D. Oliveira 1,2 , I.C. Correa 3 , J.L. Ferracane 2 , M.A.C. Sinhoreti 1 , A.B. Correr 1 1
Piracicaba Dental School, State University of Campinas, Piracicaba, Brazil 2 School of Dentistry, Oregon Health and Science University, Portland, USA 3 School of Dentistry, Federal University of Rio De Janeiro, Rio De Janeiro, Brazil Purpose: To evaluate the synergism of camphorquinone (CQ) and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) on color, light transmittance and the curing profile of experimental resin composites light-activated with a polywave LED. Methods and materials: Experimental resin composites were produced using the same organic matrix (10.1 wt% Bis-GMA, 11.4 wt% UDMA, 11.4 wt% Bis-EMA and 2.1 wt% TEGDMA) and 65 wt% filler (52 wt% 0.7 m BaBSiO2 and 13 wt% 0.05 m fumed silica) containing different CQ-amine and TPO molar concentration ratios: CQ-only; 3CQ:1TPO; 1CQ:1TPO; 1CQ:3TPO and TPO-only. Class I restorations (5 × 5 mm, 3 mm depth) were performed into a custom-designed transparent polymethylmethacrylate (PMMA) mold using a polywave LED with 16 J/cm2 (Valo Cordless, Ultradent). A jig was made to position the LED reproducibly, similar to performing a Class I restoration in the mouth, in order to establish the regions influenced by the blue and violet LED emittances. To map the degree of conversion (DC), 5 mm × 3 mm longitudinal cross-section specimens (0.3 mm thick) of the center of the restoration were evaluated using a FT-IR Microscope (Nicolet Continuum, Thermo Scientific) coupled to a FT-IR spectrometer (Nicolet Nexus 6700, Thermo Scientific) in the near-IR spectrum. Color and light transmittance change during curing were also evaluated using a pre-calibrated chromameter (CR221, Konica Minolta) and a resin calibrator (MARC, BlueLight Analytics) in three different thickness, 1 mm, 2 mm and 3 mm. Data were analyzed using ANOVA and Tukey’s test for multiple comparisons (a = 0.05; ˇ = 0.2). Results: TPO addition to a CQ-amine-based composite reduced the initial yellowness of the composite, as well as the amount of color change after curing (p < 0.001); but CQ concentration increased LED light-absorbance at greater depths. As can be observed in Fig. 1, up to 2 mm depth, no differences in the DC were found among the different photo-initiator groups, regardless of the regions influenced by the blue and violet emittance. Starting at 2 mm depth, TPO-only and 1CQ:3TPO composites showed a decrease in curing efficiency, except in the center region (where there is overlap of the two LEDs) for 1CQ:3TPO. CQ-only and 3CQ:1TPO composites showed decreased curing efficiency at the 3 mm depth in the region under the violet emittance. 1CQ:1TPO also showed decreased curing efficiency at the 3 mm depth in all regions.
d e n t a l m a t e r i a l s 3 1 S ( 2 0 1 5 ) e1–e66
insight for future antimicrobial, bioactivity, and osseointegration testing of implant materials. http://dx.doi.org/10.1016/j.dental.2015.08.138 P3 Curing profiles of CQ- and TPO-based composites using polywave leds D. Oliveira 1,2,∗ , M.G. Rocha 1,2 , I.C. Correa 3 , A.B. Correr 1 , J.L. Ferracane 2 , M.A.C. Sinhoreti 1 1
Piracicaba Dental School, State University of Campinas, Piracicaba, Brazil 2 School of Dentistry, Oregon Health and Science University, Portland, USA 3 School of Dentistry, Federal University of Rio De Janeiro, Rio De Janeiro, Brazil
Purpose: To evaluate the influence of beam-profile on light transmittance and curing profile of camphorquinone (CQ) and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO)based resin composites using different polywave LEDs. Methods and materials: Experimental resin-based composites were produced using the same organic matrix (10.1 wt% Bis-GMA, 11.4 wt% UDMA, 11.4 wt% Bis-EMA and 2.1 wt% TEGDMA) containing either CQ (0.2 wt%) or TPO (0.4 wt%) and 65 wt% filler (52 wt% 0.7 m BaBSiO2 and 13 wt% 0.05 m fumed silica). Class I restorations (5 × 5 mm, 3 mm depth) were performed into a custom-designed transparent polymethylmethacrylate (PMMA) mold using two polywave LEDs with 24 J/cm2 (Bluephase G2, Ivoclar Vivadent and Valo Cordless, Ultradent). Each LED was reproducibly positioned in order to establish the regions of the restoration exposed to the light emitted from the blue and violet LEDs, and the overlapping region in between. To map the degree of conversion (DC), 5 mm × 3 mm longitudinal cross-sectional specimens (0.3 mm thick) of the center of the restoration were evaluated using a FT-IR Microscope (Nicolet Continuum, Thermo Scientific) coupled to a FT-IR spectrometer (Nicolet Nexus 6700, Thermo Scientific) in the near-IR region. Light transmittance change during curing was also evaluated using a resin calibrator (MARC, BlueLight Analytics) for composites of three different thicknesses: 1 mm, 2 mm and 3 mm. Data were analyzed using ANOVA and Tukey’s test for multiple comparisons (a = 0.05; ˇ = 0.2). Results: CQ-based composite demonstrated lower initial light-transmittance before curing compared to TPO, but the highest change and highest light-transmittance after curing (p < 0.001). There were no differences in the curing profile between the light curing units tested (p = 0.89); similar effects of the different LED regions (blue, center and violet) were found (p = 0.09) (Fig. 1). Up to 1 mm in depth, no differences in the DC were found between the photo-initiators or among the different regions evaluated. Starting at the 2 mm depth, the TPO-based composite showed a decrease in cure efficiency near the blue emittance region. The CQ-based composites only showed decreased cure efficiency at the 3 mm depth in the violet emittance region.
Fig. 1
Conclusion: Composites based on CQ demonstrate higher light-transmittance than TPO-based composite. CQ- and TPO-based composites presented similar curing profiles at increments up to 1 mm thick; but at greater thicknesses, composites with TPO presented a decrease in depth of cure starting at 2 mm and CQ-based composites at 3 mm near the wavelength emittance outside their absortivity. http://dx.doi.org/10.1016/j.dental.2015.08.139 P4 Remineralization of bonded-dentin through Ca/P-releasing adhesives and/or biomimetic analogs G. Abuna 1,∗ , V.P. Feitosa 2 , S. Sauro 3 , G. Cama 4 , M. Giannini 1 , M.A. Sinhoreti 1 1
State University of Campinas, Brazil Federal University of Ceara, Brazil 3 Cardenal Herrera University, Spain 4 Ghent University, Belgium 2
Purpose: To assess the remineralization of an experimental Ca2+ /PO4 3− -releasing resin-based adhesive applied on mineral-depleted dentin pre-treated with primers doped with or without biomimetic analogs. Methods and materials: A two-step adhesive system was created by incorporating sodium trimetaphosphate (TMP) and/or polyacrylic acid (PAA) into a GDMAP-(glycerol dimethacrylate-dihydrogen-phosphate)-based primer. Equimolar amounts of beta-tri-calcium-phosphate (betaTCP) and monocalcium-phosphate-monohydrate (MCPM) were incorporated into a light-curable resin adhesive. An analogs-free primer and a filer-free adhesive were used as control. Fifty extracted human molars were prepared and divided into 5 groups (n = 10); the specimens were bonded as following: Control: analogs-free primer/filer-free adhesive; Primer + Ca/P: control primer/ion-releasing adhesive; PAA + Ca/P: PAA-containing primer/ion-releasing adhesive;
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TMP + Ca/P: TMP-containing primer/ion-releasing adhesive; TMP/PAA + Ca/P: TMP/PAA-containing primer/ion-releasing adhesive. Build-ups were made using Filtek Z350XT. Specimens were challenged under simulated pulpal pressure (SPP) for 24 h or 6 months and subsequently submitted to TBS; results were analyzed by two-way ANOVA and Tukey test (p < 0.05). Three sticks from each group were prepared for SEM nanoleakage analysis. In order to characterize the phosphate precipitation in totally demineralized in EDTA (17%), five dentin discs each group were pre-treated with the tested primers as previously described and kept in intimate contact in artificial saliva (AS) with the adhesive doped with or without ion-releasing micro-filler up to 6 months. The same specimens were then processed for Transmission Electron Microscopy (TEM) analysis to assess the intra- and/or extra-fibrilar collagen remineralization. Results: The TBS of the control group was significantly reduced after 6 months SPP (p > 0.05). Only the specimens bonded with the ion-releasing adhesive on dentin surface primed without biomimetic analogs or with both PAA and TMP showed stable TBS over time (p < 0.05). The use of PAA or STMP alone reduced the initial TBS (p > 0.05). Nanoleakage increased after SPP in the control group specimens, but reduced in the specimens treated with the ion-releasing resin. All the specimens treated with the ion-releasing adhesive showed during FTIR analysis increase of peaks at 947, 1033 and 1092 cm−1 attributed to PO4 of apatite. TEM showed nano-needles intra-fibrillar precipitation especially in the specimens treated with the ion-releasing adhesive in presence of both the biomimetic analogs. Conclusion: The experiment Ca/PO-releasing adhesive evokes intra-fibrillar dentin collagen and prevents degradation of resin–dentin interfaces particularly when used in combination with a primer containing both the biomimetic analogs (TMP and PAA). However, stable bond strength can be achieved after 6-month storage under SPP also when the Ca/PO-releasing resin is used in combination with the GDMAPbased primer.
http://dx.doi.org/10.1016/j.dental.2015.08.140
P5 Synergism of CQ-amine and TPO in experimental resin composites M.G. Rocha 1,2,∗ , D. Oliveira 1,2 , I.C. Correa 3 , J.L. Ferracane 2 , M.A.C. Sinhoreti 1 , A.B. Correr 1 1
Piracicaba Dental School, State University of Campinas, Piracicaba, Brazil 2 School of Dentistry, Oregon Health and Science University, Portland, USA 3 School of Dentistry, Federal University of Rio De Janeiro, Rio De Janeiro, Brazil Purpose: To evaluate the synergism of camphorquinone (CQ) and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) on color, light transmittance and the curing profile of experimental resin composites light-activated with a polywave LED. Methods and materials: Experimental resin composites were produced using the same organic matrix (10.1 wt% Bis-GMA, 11.4 wt% UDMA, 11.4 wt% Bis-EMA and 2.1 wt% TEGDMA) and 65 wt% filler (52 wt% 0.7 m BaBSiO2 and 13 wt% 0.05 m fumed silica) containing different CQ-amine and TPO molar concentration ratios: CQ-only; 3CQ:1TPO; 1CQ:1TPO; 1CQ:3TPO and TPO-only. Class I restorations (5 × 5 mm, 3 mm depth) were performed into a custom-designed transparent polymethylmethacrylate (PMMA) mold using a polywave LED with 16 J/cm2 (Valo Cordless, Ultradent). A jig was made to position the LED reproducibly, similar to performing a Class I restoration in the mouth, in order to establish the regions influenced by the blue and violet LED emittances. To map the degree of conversion (DC), 5 mm × 3 mm longitudinal cross-section specimens (0.3 mm thick) of the center of the restoration were evaluated using a FT-IR Microscope (Nicolet Continuum, Thermo Scientific) coupled to a FT-IR spectrometer (Nicolet Nexus 6700, Thermo Scientific) in the near-IR spectrum. Color and light transmittance change during curing were also evaluated using a pre-calibrated chromameter (CR221, Konica Minolta) and a resin calibrator (MARC, BlueLight Analytics) in three different thickness, 1 mm, 2 mm and 3 mm. Data were analyzed using ANOVA and Tukey’s test for multiple comparisons (a = 0.05; ˇ = 0.2). Results: TPO addition to a CQ-amine-based composite reduced the initial yellowness of the composite, as well as the amount of color change after curing (p < 0.001); but CQ concentration increased LED light-absorbance at greater depths. As can be observed in Fig. 1, up to 2 mm depth, no differences in the DC were found among the different photo-initiator groups, regardless of the regions influenced by the blue and violet emittance. Starting at 2 mm depth, TPO-only and 1CQ:3TPO composites showed a decrease in curing efficiency, except in the center region (where there is overlap of the two LEDs) for 1CQ:3TPO. CQ-only and 3CQ:1TPO composites showed decreased curing efficiency at the 3 mm depth in the region under the violet emittance. 1CQ:1TPO also showed decreased curing efficiency at the 3 mm depth in all regions.