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This research analyzed the effect of the manufacturing method on the flexural strength and color stability of 3D-printed resins used for producing indirect restorations. For this, two dental restorative biocompatible resin materials, OnX (OnX, SprintRay) and CB (Crown and Bridge, Dentca), were divided into 2 groups according with manufacturing method (printed with a Pro95 3D printer - SprintRay; and not printed, with samples obtained with the fluid resin being poured on PVS molds for further light activation in the post-curing process), and subdivided into 2 groups according to the post-curing method: VG (Valo Grand, Ultradent Products) for 120 s and PC (Procure 2, SprintRay). Bar-shaped samples were used to evaluate the flexural strength 24 h after storage in distilled water at 37 °C using a universal testing machine. Disk-shaped samples were used to evaluate the color stability with a spectrophotometer at baseline, after 1-7 days in dark dry storage at 37 °C, and after 1 day of artificial aging in water at 60 °C. Data were evaluated using 3-way ANOVA (flexural strength) and 4-way repeated measures ANOVA (color stability), followed by the Tukey's HSD test (α = .05). Flexural strength showed significant results for resin (p < .001), while manufacturing and post-curing methods were not significant (p > .05). The interaction effects between resin and manufacturing method (p = .978), and between resin, manufacturing method and post-curing method (p = .659) were not significant. In general, OnX showed higher flexural strength values than CB, regardless of manufacturing method or post-curing protocol. Color stability results showed significant results for resin (p < .001), time (p < .001), resin and time (p = .029), and resin and curing method (p < .001), but no differences considering resin and manufacturing mode (p = .87), or resin, manufacturing method and curing method (p = .35). In general, OnX showed a higher color change than CB, longer storage times resulted in increased color change for both materials, and CB cured with VG showed lower color alteration than CB cured with PC2. The manufacturing method (3D printed or not 3D printed) does not seem to influence the flexural strength and color stability of 3D printed resins. This may indicate that, at least from a physical-mechanical perspective, the final properties of the material are mainly dependent on the post-curing process.
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OBJECTIVES: To evaluate the effect of different ratios of Bis-EMA/Bis-GMA resin mixtures on the inherent viscosity and curing-related properties: including degree of cure (DC%), shrinkage strain, Knoop micro-hardness (KH) and flexural strength of resin-impregnated fiber-bundles. METHODS: Bis-EMA/Bis-GMA monomers were mixed (by weight) in the following ratios: M1 = 30 %/70 %, M2 = 50 %/50 %, M3 = 70 %/30 %, and M4 = 100 %/0 %. Standard measurements were made of refractive index, viscosity, degree of conversion, shrinkage strain and Knoop hardness (KHN). For 60 % glass fiber-bundles impregnated with 40 % resin, three-point bending test for flexural strength and shrinkage strain were measured. Data were analyzed by One-way ANOVA and Bonferroni post-hoc tests (α = 0.05). RESULTS: For resin mixtures, increasing Bis-EMA proportion decreased refractive index (p < 0.05), and viscosity (p < 0.05), and increased monomer conversion (DC%), shrinkage strain and KHN (p < 0.05). DC% increased after 1 h for all resin mixtures. The shrinkage strain and flexural strength of resin-impregnated fiber-bundles reduced with increased Bis-EMA. SIGNIFICANCE: Monomeric mixtures with highest amounts of Bis-EMA showed enhancement in several clinically-relevant properties and polymerization of respective resin-impregnated glass fibers. This makes them potential candidates for impregnating glass fibers in fiber-reinforced restorations.
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Patients are always looking for conservative, esthetic, and long-lasting dental restorations, and the technique used directly influences the longevity of the treatment. The location of the restoration in the mouth and the extent of the decay influence the treatment choice. The larger the dimensions of the cavity preparation, the greater the difficulties in restoring the tooth using direct techniques. The semidirect technique, when indicated, can achieve satisfactory results. It is a relatively easy procedure, consisting of tooth preparation to receive an indirect restoration, fabrication of an alginate impression, fabrication of the composite resin restoration on a flexible cast, cementation, removal of excess cement, and occlusal adjustment. The aim of this case report is to present a viable alternative to direct and indirect restorations for posterior teeth with extensive decay. The article describes the extraoral semidirect technique for fabricating a composite resin restoration, highlighting its indications and discussing advantages and disadvantages.
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Resinas Compuestas , Restauración Dental Permanente , Humanos , Resinas Compuestas/uso terapéutico , Restauración Dental Permanente/métodos , Estudios de Seguimiento , Femenino , Caries Dental/terapia , Masculino , Preparación de la Cavidad Dental/métodos , Cementación/métodos , Materiales Dentales/uso terapéutico , Materiales Dentales/química , Diente Molar , Técnica de Impresión DentalRESUMEN
This research assessed the effects of pre-heating on the physical-mechanical-chemical properties of different resin composites. For this, resin composites were evaluated in 6 levels: Admira/ADM, Vitra/VIT, Filtek Supreme/FS, Filtek Supreme Flowable/FSF, Filtek One/FO, and Filtek Bulk Fill Flowable/FBF; temperature was evaluated in 4 levels using a composite heater: room temperature/22 ºC, 37 ºC, 54 ºC, and 68 ºC. Response variables were: degree of conversion/DC, flexural strength/FS and color stability/ΔE (immediately after light curing/LC, after 7 days of dark-dry-storage, and after 24 h and 3 days of artificial aging in water at 60 ºC). Data were subjected to 2-way ANOVA (DC and FR) and 3-way repeated measurements ANOVA (ΔE), all followed by Tukey's test (α = 5%). DC were similar (FBF, FS, and FSF) or increased (ADM, FO, and VIT) as the temperature increased. Results of FR were unchanged or increased for all composites except VIT and ADM. High-viscosity composites (VIT and FS) showed higher FR values than low-viscosity composite (FSF). For bulk-fill composites, FBF and FO showed similar results, but lower than high-viscosity composites. Results of color stability showed acceptable values up to 3 days aging except for ADM and FSF. ΔE was not influenced by pre-heating and, overall, ΔE: FS < VIT < FO < FSF < ADM < FBF. Only VIT and FS showed ΔE ≤ 3.3 (clinical threshold). Therefore, the effects of pre-heating depend on the material. The tested materials generally showed similar or enhanced properties after pre-heating (except ADM and VIT).
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Background: This paper analyses the effects of root canal fragility and irrigation on external temperature change (ΔT) of different sections of roots during post-space preparation. Material and Methods: Forty endodontic treated human premolars were evaluated. Roots were divided into four groups based on their root wall thickness (fragile or non-fragile), and whether they received irrigation (yes or no) during post-space preparation. Initial root canal temperature was kept at 37°C. ∆T was evaluated with thermistors attached to the cervical and apical thirds of the roots during two preparation steps: 1) removal of gutta-percha with Largo drills, and 2) using the specific drill for post-space preparation for cementation of fiber-reinforced posts. In the irrigated groups, we used a 2% chlorhexidine solution during the exchange of drills. ∆T data was analyzed using four-way ANOVA with repeated measures and Tukey's test (α = 0.05). Results: Significant differences in ∆T based on root fragility (p = 0.017), root canal third (p = 0.013), and preparation step (p = 0.006). We found that non-fragile roots tended to have higher ∆T than fragile roots, particularly in the apical third, during the use of the second drill. Irrigation did not have a significant effect on temperature variation, regardless of root wall thickness or the third evaluated (p> 0.05). Conclusions: Findings suggest that root wall thickness and the third evaluated influence temperature changes during post-space preparation for cementation of posts. Non-fragile roots showed greater temperature variation than fragile roots, while irrigation did not significantly impact temperature changes. Key words:Temperature, post and core technique, tooth preparation.
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Determining the appropriate technique for diastema closure is challenging, and the decision must be evidence based. The objective of these case reports is to describe different approaches to diastema closure using direct and indirect techniques, focusing on the characteristics of the patient and clinical requirements to guide treatment. In the first case, a 16-year-old patient had multiple diastemas in the maxillary anterior dentition. The clinical evaluation revealed microdontia of the lateral incisors and malpositioned teeth. The treatment included tooth whitening and placement of composite resin veneers using a direct technique. In the second case, a 54-year-old patient displayed a disharmonious and esthetically compromised smile due to small teeth, color changes, multiple diastemas, incisal wear, and severe dentogingival disproportion. Based on the patient's expectations, the patient's age, and the presence of a "black triangle" interdental space, a multidisciplinary restorative treatment was proposed, including gingivoplasty, tooth whitening, and placement of ceramic laminate veneers using an indirect technique. Both approaches achieved successful esthetic rehabilitation and diastema closure with minimal intervention. The choice of procedure and restorative material, as well as the need for tooth preparation, varied based on the clinical requirements, patient expectations, and financial constraints. Careful treatment planning avoided lengthy and inefficient procedures.
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Diastema , Maloclusión , Humanos , Adolescente , Persona de Mediana Edad , Diastema/terapia , Estética Dental , Coronas con Frente Estético , Cerámica , Resinas Compuestas/uso terapéuticoRESUMEN
OBJECTIVE: This case report described the use of a stamping technique associated with a bulk fill composite to restore an ICDAS 4 carious lesion on a posterior tooth. The 4-year follow-up is also presented. CLINICAL CONSIDERATIONS: A 32-year-old patient presented a carious lesion on tooth 36 with an underlying dark shadow at the dentin seen from the noncavitated enamel occlusal surface, which was compatible with an ICDAS 4 carious lesion. The lesion was radiographically detected and the caries disease was treated with dietary and hygiene habits orientations. Before accessing the lesion and selectively removing the carious tissue, an occlusal stamp was made by applying a flowable resin composite to copy the anatomy of the noncavitated enamel surface. The cavity was restored using a bulk fill resin composite (Opus Bulk Fill, FGM) with 4-mm-thick increments. Before curing the last increment, a Teflon band was adapted at the uncured bulk fill composite surface and the occlusal stamp made with the flowable composite was pressed against it to reproduce the natural characteristics and initial occlusal anatomy. The top surface was light-activated for 40 s. After 4 years, small wear could be seen in the restoration, but still within clinically acceptable levels. CONCLUSION: The occlusal stamp technique allows reproduction of the natural anatomy of teeth affected by ICDAS 4 carious lesions with good clinical longevity over 4 years. CLINICAL SIGNIFICANCE: This case report presents the use of the stamp technique to restore a tooth affected by an ICDAS 4 lesion, in which a carious process reached the dentin and the enamel anatomy was still preserved. The bulk fill resin composite associated with the occlusal stamp was chosen to quickly restore the cavity with clinical predictability. Bulk fill composites allow the insertion of up to 4-mm-thick increments and offer lower shrinkage stress, good clinical longevity and a less time-consuming procedure in cases of posterior teeth, especially if associated with the stamp technique.
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Caries Dental , Humanos , Adulto , Estudios de Seguimiento , Caries Dental/terapia , Esmalte Dental , Resinas Compuestas , Restauración Dental PermanenteRESUMEN
Objective: The aim of this in vitro study w as t o analyze the influence of the titanium dioxide nanotubes i n a self-cure mode polymerization of a dual resin luting agent through push out bond strength and radiopacity tests. Material and Methods: After mixed with a commercial du al self-adhesive resin cement, three concentrations o f tit anium dioxide nanotubes (0.3, 0.6, and 0.9% by weight) we re analyzed in self-curing mode. T he bond strength to bovine root dentin and fi berglass posts was assessed with the push out bond str ength t est and was evaluated in three thirds (cervical, middle and apical) (n=10), followed by failure mode analysis (SEM), and the ISO standard 9917-2 was followed for radiopacity test (n=10). Data were statistically analyzed by one-way ANOVA test, followed by Tukey's test (α=0.05). Results: Reinforced self-adhesive resin cement with 0.6% titanium dioxide nanotubes showed significant difference compared to the control gr oup for push out test (p=0.00158). The modified groups did not s how significant difference among thirds (p=0.782). Radiopacity sh owed higher value for group w ith 0.9% titanium dioxide nanotubes in comparison w ith control group (p<0.001). Conclusion: The addition of titanium dioxide nanotubes to a self-adhesive resin cement increased the bond strength to dentin and radiopacity values in the self-cure polymerization mode (AU)
Objetivo: O objetivo deste estudo in vitro foi analisar a influência de nanotubos de dióxido de titânio na polimerização química de um agente cimentante resinoso dual através de testes de resistência à união e radiopacidade. Material e Métodos: Após misturado com um cimento resinoso auto-adesivo comercial, três concentrações de nanotubos de dióxido de titânio (0,3, 0,6 e 0,9% em peso) foram analisadas. A resistência da união para a dentina da raiz bovina e os pinos de fibra de vidro foi avaliada pelo teste de push-out e avaliada em três terços (cervical, médio e apical) (n = 10), seguido pelo análise de modo de falha (MEV) e a norma ISO 9917-2 foi seguido para teste de radiopacidade (n = 10). Os dados foram analisados estatisticamente pelo teste ANOVA um fator seguido do teste de Tukey (α = 0,05). Resultados: O cimento resinoso auto-adesivo reforçado com nanotubos de dióxido de titânio a 0,6% mostrou diferença significativa em comparação com o grupo controle para teste de push-out (p=0,00158). Os grupos modificados não mostraram diferença significativa entre os terços (p=0,782). A radiopacidade mostrou maior valor para o grupo com nanotubos de dióxido de titânio 0,9% em comparação com o grupo controle (p<0,001). Conclusão: A adição de nanotubos de dióxido de titânio a um cimento resinoso auto-adesivo aumentou a os valores de resistência de união à dentina e radiopacidade no modo de polimerização química do agente cimentante (AU)
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Titanio , Cementos Dentales , Pins Dentales , NanotubosRESUMEN
OBJECTIVE: This study evaluated the microshear bond strength of a resin cement to Y-TZP after different methods of TiO2 nanotubes (nTiO2) incorporation on pre-sintered Y-TZP surfaces. METHODS: nTiO2 were synthesized and incorporated on Y-TZP slices as follows (n = 15): 1) nTiO2 mixed with isopropyl alcohol/manual application (MAl); 2) nTiO2 mixed with acetone/manual application (MAc); 3) nTiO2 mixed with isopropyl alcohol/high-pressure vacuum application (HPVAl); 4) nTiO2 mixed with acetone/high-pressure vacuum application (HPVAc). As controls, surfaces were sandblasted with Al2O3 (OX) or Rocatec silicatization (ROC). All ceramics were sintered after nTiO2 incorporation. Surface treatments of OX and ROC were made after sintering. Surfaces were characterized by confocal laser microscopy, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Resin composite cylinders (1.40 mm diameter and 1 mm height) were cemented with a resin cement, stored in water at 37 °C for 24 h and thermocycled for 10 000 cycles before microshear bond strength evaluation. Data were analyzed with one-way ANOVA and Games-Howell (α = 0.05), and fracture analysis was performed using a stereomicroscope. RESULTS: EDS confirmed the presence of TiO2 on treated Y-TZP. The confocal analysis showed higher roughness for HPVAc and OX. There were significant differences between surface treatments (p < 0.001). HPVAl (22.96 ± 10.3), OX (34.16 ± 7.9) and ROC (27.71 ± 9.4) showed higher microshear bond strengths and were statistically similar (p > 0.05). MAC showed intermediary values, and HPVAc and MAl presented decreased bond strength, with a high percentage of premature debonding. CONCLUSION: High-pressure vacuum application of nTiO2 mixed with isopropyl alcohol was able to produce bond strength values compared to conventional air abrasion and Rocatec silicatization. SIGNIFICANCE: The infiltration of TiO2 nanostructures on the pre-sintered Y-TZP is an interesting approach that can improve bond strength without the need of sandblasting methods.
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Recubrimiento Dental Adhesivo , Nanotubos , 2-Propanol , Acetona , Abrasión Dental por Aire , Recubrimiento Dental Adhesivo/métodos , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Cementos de Resina/química , Resistencia al Corte , Propiedades de Superficie , Titanio , Itrio/química , Circonio/químicaRESUMEN
Introduction: Bonding to crystalline zirconia is currently a challenge. Properly cured adhesives are crucial to optimize this bond, and that in turn is influenced by the initial mobility of the system, as well as by the reactivity of the initiators. Aim: This study aimed to characterize adhesives containing monomer mixtures of different viscosities and double and triple photoinitiator systems; and to evaluate the bonding to Y-TZP zirconia, when adhesives were light-activated with monowave or polywave light-curing units (LCU). Materials and methods: Adhesives were formulated at a 1:1 weight proportion of Bis-GMA/TEGDMA or Bis-GMA/Bis-EMA. To these mixtures 0.5 wt% of CQ, 0.5-1.0 wt% of DABE, 0.5-1.0 wt% of DPIHP, or 0.5-1.0 wt% of TAS-Sb were added and used as photoinitiator systems. A total of ten adhesives were prepared. Resin composite cylinders were cemented on zirconia slices and 6000 thermal cycles were performed. Degree of conversion (DC), sorption (SO) and solubility (SL) after 7 days of water storage, and microshear bond strength (µSBS) were evaluated. Data were analyzed with three-way ANOVA and Tukey's HSD (α = 0.05). Results: Bis-GMA/Bis-EMA combined with either CQ/DABE or CQ/DABE/TAS-Sb presented the highest DC, and no significant differences were observed for LCUs (p = .298). CQ/DABE < CQ/DABE/TAS-Sb ≈ CQ/DABE/DPIHP and the polywave LCU showed smaller overall SO (p < .05). Bis-GMA/TEGDMA with CQ/DABE cured with the polywave LCU presented the lowest SO. SL varied as follows: CQ/DABE/TAS-Sb < CQ/DABE/DPIHP < CQ/DABE (p < .001). For µSBS, only the factor photoinitiator system was significant (p = .045). All mean values were above 30 MPa, with higher values being observed for BIS-GMA/TEGDMA and CQ/DABE. Conclusion: It can be concluded that the adhesive containing CQ/DABE/TAS-Sb as coinitiator of Bis-GMA/Bis-EMA mixtures produced a material with higher DC and lower SL, while bond strength values were similar to the ones obtained by CQ/DABE.
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BACKGROUND: Provisional materials must have enough strength to withstand masticatory loads without suffering deformation or fracture, and their surfaces must have good finishing and polishing characteristics to reduce biofilm accumulation. Thus, the purpose of this study was to investigate the best polishing protocol for different bis-acryl composite resins in comparison with a conventional resin composite and a self-curing acrylic resin aiming to obtain a smooth restoration surface and resistance to wear. MATERIAL AND METHODS: One hundred and four samples (15 mm length x 5 mm width x 4 mm depth) were prepared and divided into four groups according to the material tested: Protemp 4 and Structur 3 bis-acryl composite resins, Dencor self-curing acrylic resin, Filtek Z350XT conventional composite resin. The polishing procedures were performed with Sof-Lex Pop-On discs or Sof-Lex spirals and abrasion procedures were performed on a brushing machine. The surface roughness was analyzed at three periods (initial, post-polishing and post-brushing) and the wear was evaluated after simulated brushing. The results were submitted to ANOVA followed by the Tukey (α = 0.05). RESULTS: Filtek Z350XT groups showed the lowest values of initial surface roughness followed by Structur 3, Protemp 4 and Dencor groups. After polishing and simulated brushing, Filtek Z350XT groups also presented the lowest roughness values, followed by bis-acryl groups (Structur 3 and Protemp 4) and Dencor groups demonstrated the highest surface roughness. Sof-Lex Pop-On discs system exhibited lower roughness values for all groups. CONCLUSIONS: Sof-Lex Pop-On discs system promoted the best polishing for all groups. Overall, Filtek Z350XT groups presented lower results for both roughness and wear for all periods evaluated, followed by Protemp 4 and Structur 3, meanwhile Dencor groups presented the highest roughness and wear values for all periods. Key words:Acrylic resin, bis-acryl, brushing, composite resin, polishing, roughness, wear.
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Objetivo: O objetivo foi avaliar a resistência de união de seis adesivos experimentais contendo sistemas fotoiniciadores binários ou ternários, associados a três diferentes concentrações de MDP (0-12% em peso) após 12 meses de armazenamento em água destilada. Material e Métodos: Adesivos experimentais foram preparados com: bis-GMA, UDMA, bis-EMA, TEGDMA, HEMA, BHT e etanol, contendo sistemas fotoiniciadores binários (CQ/amina) ou ternários (CQ/amina/DPIHFP 0,5% em peso). Foi adicionado a esta composição 0%, 6% ou 12% em peso de MDP. Os sistemas adesivos foram aplicados seguindo o protocolo com condicionamento ácido. Moldes cilíndricos transparentes foram colocados sobre a dentina hibridizada, preenchidos com resina composta e fotopolimerizados. Os corpos-de-prova foram armazenados em água destilada a 37oC por 24h ou 12 meses e submetidos ao ensaio de microcisalhamento (n=6). Os dados foram analisados por ANOVA de três fatores e teste de Tukey (α=5%). Resultados: Para o sistema binário, após 12 meses de armazenamento, todos os valores de resistência de união foram semelhantes. Em relação à degradação da resistência de adesão ao longo do tempo, as formulações de MDP de 6% e 12% mostraram resistência de união mais estável do que 0% de MDP. Para o sistema ternário, todas as formulações (0%, 6% e 12% em massa de MDP) mostraram resistência de união estável em função do tempo. Conclusão: Para o sistema binário, as concentrações de 6 e 12% em massa de MDP foram capazes de manter a resistência de união em função do tempo, enquanto que para o sistema ternário, a estabilidade de união foi obtida independentemente da concentração de MDP. Pode-se concluir que, para a formulação dos adesivos utilizados neste estudo, independente do sistema fotoiniciador, a concentração de 12% MDP apresentou valores de resistência de união mais estáveis após 12 meses de armazenamento em água (AU)
Objective: The aim was to evaluate the bond strength of six experimental adhesives containing binary or ternary photoinitiator systems, associated with three different MDP concentrations (0-12wt%) after 12 months of storage in distilled water. Material and Methods: Experimental adhesives were prepared with: bis-GMA, UDMA, bis-EMA, TEGDMA, HEMA, BHT, and ethanol, containing binary (CQ/amine) or ternary (CQ/amine/DPIHFP (diphenyliodonium hexafluorophosphate) 0.5wt%) photoinitiator systems. It was added to this composition 0wt%, 6wt%, or 12wt% of MDP. The adhesive systems were applied following the etch-and-rinse protocol. Transparent cylindrical molds were placed on the hybridized dentin, filled with composite resin and light-cured. The specimens were stored in distilled water at 37oC for 24h or 12 months and submitted to a microshear bond strength test (n=6). Data were analyzed by three-way ANOVA and Tukey's test (α=5%). Results: For the binary system, after 12 months of storage, all bond strength values were similar. Regarding bond strength degradation over time, 6wt% and 12wt% MDP formulations showed more stable bond strength than 0wt% MDP. For the ternary system, all formulations (0wt%, 6wt% and 12wt%) showed stable bond strength over time. Conclusion: For the binary photoinitiator system, the 6wt% and 12wt% MDP concentrations were able to keep bond strength stable over time, while for the ternary system, bond strength stability was achieved regardless the MDP concentration. (AU)
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Cementos Dentales , Fotoiniciadores DentalesRESUMEN
OBJECTIVE: To evaluate the influence of the addition of functionalized and non-functionalized TiO2 nanostructures on properties of a resin composite. METHODS: TiO2 nanostructures were synthesized and functionalized, using 3-(aminopropyl)triethoxysilane (APTMS) and 3-(trimethoxysilyl)propyl methacrylate (TSMPM). Characterizations were performed with XRD, EDS, TEM, and TGA. Resin composites containing Bis-GMA/TEGDMA, CQ, DABE, and barium-aluminum silicate glass were produced according to TiO2 nanostructure (nanotube or nanoparticle), concentration (0.3 or 0.9 wt%), and functionalization (APTMS or TSMPM). The resin composite without nanostructures was used as control. The amount of fillers was kept constant at 78.3 wt% for all materials. The degree of conversion (DC - at 0 h and 24 h), maximum polymerization rate (Rpmax), and Knoop microhardness (KHN before and after ethanol softening) were evaluated. Data were analyzed with two-way ANOVA with repeated measures and Tukey's HSD (α = 0.05). RESULTS: TGA results demonstrated that functionalizations were effective for both nanostructures. For DC, resin composites, time and interaction effect were significant (p < 0.001). Higher DC was found for 0.3-wt%-functionalized-nanotubes at 24 h. For nanoparticles, only 0.9-wt%-non-functionalized and 0.3-wt%-APTMS-functionalized showed DC similar to the control and all other groups showed higher DC (p < 0.05). Rpmax was higher for 0.3-wt%-APTMS-nanotubes, which corresponded to higher DC after 24 h. The lowest Rpmax occurred for 0.9-wt%-TSMPM-nanotubes, which showed smaller DC at 0 h. For KHN, resin composites, ethanol softening and interaction effect were significant (p < 0.001). KHN decreased after ethanol softening all groups, except for 0.3-wt%-TSMPM-nanotubes, 0.9-wt%-TSMPM-nanotubes, and 0.3-wt%-non-functionalized-nanoparticles. CONCLUSION: The resin with 0.3-wt%-TSMPM-nanotubes showed higher DC after 24 h, while being the most stable material after the ethanol softening. SIGNIFICANCE: The addition of functionalized TiO2 nanostructures in resin-based materials may improve the properties of the material.
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Nanopartículas , Nanotubos , Bisfenol A Glicidil Metacrilato , Resinas Compuestas , Ensayo de Materiales , Metacrilatos , Polietilenglicoles , Ácidos Polimetacrílicos , Propiedades de Superficie , TitanioRESUMEN
The aim of this research was to evaluate the influence of MDP (10-methacryloyloxydecyl dihydrogen phosphate) concentration and application mode of experimental adhesives on microshear bond strength (µSBS) to dentin after storage in distilled water at 37°C for 24h and 6 months. Five experimental adhesives were prepared with: CQ, DABE, BHT, ethanol, HEMA, TEGDMA, Bis-EMA, UDMA, and Bis-GMA. Concentrations of 0 wt%, 3 wt%, 9 wt%, 12 wt% or 15 wt% of MDP were added to their composition. The adhesives were applied to flat dentin surfaces in etch-and-rinse or self-etching modes. Cylindrical molds filled with light-cured composite resin were placed above the dentin. The specimens were stored in distilled water at 37oC for 24h or 6 months and submitted to µSBS testing. The adhesives were also submitted to pH analysis. The data were analyzed by one-way ANOVA, three-way ANOVA and Tukey's test (α = 5%). All the adhesives used in the etch-and-rinse mode showed significantly higher bond strength than the adhesives applied in the self-etching approach. The 9 wt% adhesive showed the highest bond strength values, and 3 wt% was most stable after storage. A strong negative correlation between MDP concentration and pH was observed. It was concluded that the formulations with low concentrations of MDP (up to 9 wt%) showed better results for bond strength and bond strength degradation over time.
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Recubrimiento Dental Adhesivo , Adhesividad , Resinas Compuestas , Cementos Dentales , Dentina , Recubrimientos Dentinarios , Ensayo de Materiales , Cementos de Resina , Resistencia a la TracciónRESUMEN
PURPOSE: To evaluate the shear bond strength (SBS) between Y-TZP and a resin luting agent, after 1 of 2 enhancing strategies with TiO2--nts was applied, either to the resin luting agent or the Y-TZP mass, in different concentrations. METHODS: In the Strategy TiO2-nts on ceramic, the resin luting agent Panavia F2.0™ (Kuraray) and an experimental Y-TZP with added concentrations of TiO2--nts (0%, 1%, 2%, and 5% vol/vol) and a commercial Y-TZP, comprised 5 different groups (n = 10). In the Strategy TiO2-nts on cement, the resin luting agent RelyX U200™ (3 M ESPE) was added with different concentrations of TiO2--nts (0%, 0.3%, 0.6%, 0.9% wt/wt) luted to a commercial Y-TZP, comprising 4 different groups (n = 10). The Y-TZP discs were included in acrylic bases, and a cylinder (3 × 3 mm) of the correspondent luting agent for each respective group was applied over them. After 24 h, specimens were subjected to SBS assessments in a universal testing machine. Field emission scanning electron microscopy and energy dispersive X-ray spectroscopy analyses were also performed on Y-TZP surfaces. Data were analyzed via analysis of variance and Tukey tests (α = 0.05). RESULTS: TiO2-nts on ceramic influenced the bond strength significantly, but not linearly; TiO2-nts on cement did not influence bond strength when analyzed separately, nor in comparison with the first. CONCLUSION: Y-TZP enhancements with TiO2-nts led to a higher SBS with Panavia F2.0, a 5% TiO2--nt concentration presented the highest bond strength. Modified Rely X U200 did not improve SBS.
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Recubrimiento Dental Adhesivo , Nanotubos , Cementos Dentales , Análisis del Estrés Dental , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Cementos de Resina , Resistencia al Corte , Propiedades de Superficie , Titanio , Itrio , CirconioRESUMEN
Aim: To evaluate the color stability of bovine enamel with artificial white spot lesions treated with resin infiltration (ICON) or remineralization with fluoride using two storage methods. Methods: Sixty incisors were submitted to artificial white spot lesion induced by demineralization-remineralization (DE-RE) cycling. Initial color was evaluated with CIE-Lab to measure ΔEab. Demineralized teeth were divided according to the treatment of the white spot lesion (n = 20): 1) Remineralization with 2% neutral fluoride gel for 4min (control); 2) ICON application following manufacturer's recommendations; and 3) ICON with decreased drying time after the application of ethanol. After 24h, color was evaluated and samples were subdivided (n = 10) according to storage: 1) distilled water for 1 month; 2) grape juice for 10min daily. After storage, color was evaluated. L*, a* and b* data were analyzed by one-way ANOVA and ∆Eab data by two-way ANOVA followed by Tukey's HSD (α = 0.05). Results: L* was affected by juice storage, and decreased when ICON was applied with decreased drying time after the ethanol application. The same behavior occurred with a* (increase with reduced drying time), while b* was not affected. For ∆Eab significant differences were observed between groups (p = 0.0219) and storage methods (p = 0.0007). There was no interaction effect (p = 0.1118). Remineralization with fluoride presented the lowest color changes after storage in water. Conclusion: Treatment of artificial carious lesions with resin infiltration presented greater color changes than fluoride remineralization after storage in both solutions in vitro
Asunto(s)
Caries Dental , Esmalte Dental , Estética DentalRESUMEN
Abstract The aim of this research was to evaluate the influence of MDP (10-methacryloyloxydecyl dihydrogen phosphate) concentration and application mode of experimental adhesives on microshear bond strength (μSBS) to dentin after storage in distilled water at 37°C for 24h and 6 months. Five experimental adhesives were prepared with: CQ, DABE, BHT, ethanol, HEMA, TEGDMA, Bis-EMA, UDMA, and Bis-GMA. Concentrations of 0 wt%, 3 wt%, 9 wt%, 12 wt% or 15 wt% of MDP were added to their composition. The adhesives were applied to flat dentin surfaces in etch-and-rinse or self-etching modes. Cylindrical molds filled with light-cured composite resin were placed above the dentin. The specimens were stored in distilled water at 37oC for 24h or 6 months and submitted to μSBS testing. The adhesives were also submitted to pH analysis. The data were analyzed by one-way ANOVA, three-way ANOVA and Tukey's test (α = 5%). All the adhesives used in the etch-and-rinse mode showed significantly higher bond strength than the adhesives applied in the self-etching approach. The 9 wt% adhesive showed the highest bond strength values, and 3 wt% was most stable after storage. A strong negative correlation between MDP concentration and pH was observed. It was concluded that the formulations with low concentrations of MDP (up to 9 wt%) showed better results for bond strength and bond strength degradation over time.
Asunto(s)
Recubrimiento Dental Adhesivo , Resistencia a la Tracción , Ensayo de Materiales , Adhesividad , Recubrimientos Dentinarios , Resinas Compuestas , Cementos de Resina , Cementos Dentales , DentinaRESUMEN
This study aimed to evaluate the polymerization properties of bulk-fill materials (low and high-viscosity) by using high-intensity continuous light and intermittent photo-activation in terms of polymerization shrinkage stress and degree of conversion (DC). The following Bulk-fill and Conventional nanofilled resin composites were evaluated: Filtek Z350XT Flow (3M/ESPE), SureFil SDR Flow (Dentsply), Filtek Bulk Fill Flow (3M/ESPE), Filtek Z350XT (3M/ESPE) and Filtek Bulk Fill Posterior (3M/ESPE). A LED device (DB 685, Dabi Atlante) was used for both protocols: continuous uniform and intermittent photo-activation (light-on and light-off cycles) with identical radiant exposure (14 J/cm2). The polymerization shrinkage stress (n=6) was evaluated by inserting a single increment of 12 mm3 between two stainless steel plates (6×2 mm) adapted to a Universal Testing Machine (UTM), at different times. Measurements were recorded after photo-activation. The degree of conversion was evaluated by Fourier transformed infrared spectroscope (FTIR) with an attenuated total reflectance (ATR) accessory (n=5). Data were analyzed by three-way ANOVA and Tukey's HSD (α=0.05) tests. Bulk Fill Posterior presented higher shrinkage stress values when photo-activated with the intermittent technique (p<0.05). The intermittent photo-activation increased the degree of conversion for the low-viscosity bulk-fills (p<0.05). Therefore, the use of modulated photo-activation (intermittent) must be indicated with caution since its use can influence the shrinkage stress and degree of conversion of composites, which varies according to the resin formulations.
Asunto(s)
Resinas Compuestas , Ensayo de Materiales , Polimerizacion , ViscosidadRESUMEN
Abstract This study aimed to evaluate the polymerization properties of bulk-fill materials (low and high-viscosity) by using high-intensity continuous light and intermittent photo-activation in terms of polymerization shrinkage stress and degree of conversion (DC). The following Bulk-fill and Conventional nanofilled resin composites were evaluated: Filtek Z350XT Flow (3M/ESPE), SureFil SDR Flow (Dentsply), Filtek Bulk Fill Flow (3M/ESPE), Filtek Z350XT (3M/ESPE) and Filtek Bulk Fill Posterior (3M/ESPE). A LED device (DB 685, Dabi Atlante) was used for both protocols: continuous uniform and intermittent photo-activation (light-on and light-off cycles) with identical radiant exposure (14 J/cm2). The polymerization shrinkage stress (n=6) was evaluated by inserting a single increment of 12 mm3 between two stainless steel plates (6×2 mm) adapted to a Universal Testing Machine (UTM), at different times. Measurements were recorded after photo-activation. The degree of conversion was evaluated by Fourier transformed infrared spectroscope (FTIR) with an attenuated total reflectance (ATR) accessory (n=5). Data were analyzed by three-way ANOVA and Tukey's HSD (α=0.05) tests. Bulk Fill Posterior presented higher shrinkage stress values when photo-activated with the intermittent technique (p<0.05). The intermittent photo-activation increased the degree of conversion for the low-viscosity bulk-fills (p<0.05). Therefore, the use of modulated photo-activation (intermittent) must be indicated with caution since its use can influence the shrinkage stress and degree of conversion of composites, which varies according to the resin formulations.
Resumo O presente estudo teve como objetivo avaliar as propriedades de polimerização de materiais bulk-fill (baixa e alta viscosidade) utilizando luz contínua de alta intensidade e fotoativação intermitente em relação ao estresse de contração de polimerização e grau de conversão (DC). As seguintes resinas compostas Bulk-fill e nanohíbridas convencionais foram avaliadas: Filtek Z350XT Flow (3M/ESPE), SureFil SDR Flow (Dentsply), Filtek Bulk Fill Flow (3M/ESPE), Filtek Z350XT (3M/ESPE) e Filtek Bulk Fill Posterior (3M/ESPE). Um dispositivo de LED (DB 685, Dabi Atlante) foi utilizado nos dois protocolos: fotoativação contínua e intermitente contínua (ciclos de liga e desliga) com exposição idêntica (14 J/cm2). A tensão de contração de polimerização (n=6) foi avaliada através da inserção de um incremento único de 12 mm3 entre duas placas de aço inoxidável (6×2 mm) adaptadas a uma Máquina de Ensaio Universal (UTM), em tempos diferentes. As medições foram registradas após a fotoativação. O grau de conversão foi avaliado por FTIR-ATR (n=5). Os dados foram analisados pelos testes ANOVA a três fatores e teste de Tukey (α=0,05). A resina Bulk Fill Posterior apresentou maiores valores de tensão de contração quando fotoativadas com a técnica intermitente (p<0,05). A fotoativação intermitente aumentou o grau de conversão nas resinas bulk-fill de baixa viscosidade (p<0,05). Portanto, o uso de fotoativação modulada (intermitente) deve ser indicado com cautela, uma vez que seu uso pode influenciar a tensão de contração e o grau de conversão dos compósitos, o que varia de acordo com as formulações da resina.
Asunto(s)
Ensayo de Materiales , Resinas Compuestas , Viscosidad , PolimerizacionRESUMEN
OBJECTIVE: Extensive restorations in posterior teeth always bring doubts to the clinicians regarding the best protocol, mainly when structures of reinforcement were lost. OBJECTIVE: This study aimed to evaluate the effect of beveling on the fracture resistance and pattern of class II (MOD) restored teeth. METHODOLOGY: Ninety human premolars were randomly assigned into 9 groups: CTR (control/sound); NC (cavity preparation, non-restored); RU (restored, unbeveled); RTB (restored, entire angle beveling); RPB (restored, partial/occlusal beveling); EC (endodontic access/EA, non-restored); EU (EA, unbeveled); ETB (EA, entire angle beveling); EPB (EA, partial/occlusal beveling). Teeth were restored with Esthet X resin composite and stored in distilled water for 24 h before the inclusion in PVC cylinders. The axial loading tests were performed with 500 kgF at 0.5 mm/min crosshead speed until fracture of the specimens. Fracture resistance and pattern were accessed and data were analyzed using one-way ANOVA and Tukey's HSD test (α=0.05). RESULTS: Mean (±SD) failure loads ranged from 136.56 (11.62) to 174.04 (43.5) kgF in the groups tested without endodontic access. For endodontically accessed teeth, fracture resistance ranged from 95.54 (13.05) to 126.51 (19.88) kgF. Beveling of the cavosurface angle promoted the highest fracture resistance values (p<0.05) and prevented catastrophic fractures. CONCLUSIONS: Cavosurface angle beveling is capable of improving fracture resistance and pattern for both endodonticaly accessed and non-accessed teeth.