Evaluation of the ceramic laminate veneer-tooth interface after different resin cement excess removal techniques.

OBJECTIVES: To compare, in vitro, resin cement excess removal techniques at the veneer-tooth interface. MATERIALS AND METHODS: Anterior human teeth were restored with ceramic veneers and randomly divided according to the following techniques (n = 10): removal of excess resin cement with brush and dental floss, followed by light-curing with Valo (Group 1) or Elipar (Group 2) for 1 min and 40 s; tack-curing with Valo (Group 3) or Elipar (Group 4) for 1 s; and tack-curing with Valo (Group 5) or Elipar (Group 6) for 5 s. The tack-curing was followed by removal of excess with probe and dental floss and light-curing for 1 min and 40 s. The area of excess resin cement (mm2) was measured in micro-CT images using AutoCAD program. The failures at the cervical margin in the X, Y, and Z axes (µm) of greater value were measured using the DataViewer program. The specimens were submitted to microleakage with 2% basic fuchsin. RESULTS: According to the Kruskal-Wallis and multiple comparison test, the highest area of excess resin cement was found in Group 1 (5.06 mm2), which did not differ statistically from Groups 2 (3.70 mm2) and 5 (2.19 mm2). Groups 2, 3 (1.73 mm2), 4 (1.14 mm2), and 5 (2.18 mm2) did not differ statistically. Group 6 (0.77 mm2) obtained the lowest value, which did not differ statistically from Groups 3 and 4. According to the Kruskal-Wallis and Dunn test, there was no significant difference in failures in X (p = 0.981), Y (p = 0.860), and Z (p = 0.638) axes and no significant difference in microleakage (p = 0.203) among the groups. CONCLUSIONS: Tack-curing for 1 s or 5 s, followed by removal of excess resin cement using a probe and a dental floss, tended to result in a lower amount of excess material around the margin. CLINICAL RELEVANCE: The technique used for resin cement excess removal influences the amount of excess leaved at the veneer-tooth interface. Tack-curing for 1 s or 5 s is recommended to mitigate the excess resin cement.

In vitro comparison of one-step, two-step, and three-step polishing systems on the surface roughness and gloss of different resin composites.

OBJECTIVES: This laboratory study evaluated the effect of three polishing systems on the surface roughness and gloss of resin composites. MATERIALS AND METHODS: Thirty specimens (6 mm Ø × 8 mm) were fabricated from each of three resin composites: Z 350 XT (nanofill), Harmonize (nanohybrid), and Estelite Omega (supranonofill). All specimens were photopolymerized using a multi-peak LED curing unit (VALO-Standard mode), having a exitance irradiance of approximately 1000 mW/cm2 against a polyester strip (PS). 2 mm was then removed from the irradiated end (finished) using #320 abrasive paper (F). Specimens were then randomly polished (P) using a one-step (1S) (OneGloss), two-step (2S) (EVE Diacomp Twist Basic CA), or 3-step (3S) (Astropol P) system (n = 10). For PS, F, and P groups, surface roughness (Ra) was measured using a surface roughness tester, and surface gloss was measured with a glossmeter. For each specimen, the percent recovery to the PS value (%R) of surface roughness and surface gloss were calculated. Data were analyzed using two-way ANOVA, followed by Tukey's test. Surface roughness and gloss values were submitted to Pearson's correlation test (α = 0.05). All statistical testing was performed using a pre-set alpha of 0.05. RESULTS: The interaction term [resin composite × polishing system] was significant for both surface roughness (p = 0.001) and gloss (p = 0.0001). For all resin composites, the 2S and 3S systems provided a higher %R of surface roughness and gloss compared to those of the 1S system. There was a negative correlation between surface roughness and gloss, but only a few combinations showed strong correlations. CONCLUSIONS: The 2S and 3S polishing systems provided surfaces having greater smoothness and gloss compared to the 1S system. The ability to recover surface roughness and gloss was dependent on type of resin composite filler classification. CLINICAL SIGNIFICANCE: The 3S and 2S polishing systems were more effective in achieving PS values than was the 1S system for all tested resin composites. However, individual polishing systems performed differently depending on type of resin composite.

Partial Ceramic Veneer Technique for Challenging Esthetic Frontal Restorative Procedures.

Frontal darkened teeth have shown to be one of the most challenging treatments for esthetic dentistry in recent years. This case report, along with a 30-month follow-up, describes the application of a partial ceramic veneer, restricted to the mid-cervical third region, made in the upper left central incisor darkened by trauma. The procedure consisted of maintenance of the entire incisal face, as well as esthetic and morphological rehabilitation of the smile line with veneers and ultra-thin partial ceramic veneers. The planning process was thoroughly elaborated by photographs, study models, a virtual smile designed, diagnostic waxing, and reproduction in the patient's mouth through mock-up. Following, dental home bleaching, esthetic gingival contouring, and minimally invasive tooth preparation were performed. Two types of glass ceramics (lithium disilicate and feldspathic) were used in different regions due to the peculiar characteristics of resistance, finishing, and polishing. According to the present case report, preparing a cervical partial ceramic veneer is an innovative, viable, and safe approach to maintaining the incisal portion of the tooth preserved and setting a detailed tooth morphology/color. The application of partial ceramic veneer provides incisal edge preservation and simplifies the reproduction of the adjacent tooth characteristics, avoiding multiple esthetic appointments.

Are Universal Adhesives Effective for Bonding to Zirconia in the Long Term?

Background: The bond capacity of universal adhesives should be comparable to a specific primer for zirconia. Thus, this study evaluated the bond strength to zirconia of four universal adhesives and a zirconia primer over long-term storage. Materials and Methods: The surfaces of 75 samples of zirconia were sandblasted with 50 µm aluminum oxide particles and then divided into groups (n = 15): G1 - Single Bond Universal (SBU); G2 - All Bond Universal; G3 - Peak Universal Bond; G4 - Ambar Universal (AU), and G5 - Z-Prime Plus (ZP). A cone of resin composite was constructed on the applied materials. The samples were submitted to a tensile bond strength test after 24 h using a universal testing machine. Then, the remaining materials were removed from the sample surfaces, and the surfaces were polished and sandblasted again as previously described to obtain the same groups. These new samples were stored in distilled water at 37°C for 12 months and then submitted to a tensile bond strength test. The data were analyzed by two-way analysis of variance and Tukey's test (α =0.05). Results: The material factor (P = 0.001) and the storage factor (P = 0.001) were significant, and the interaction was not significant (P = 0.117). According to Tukey's test, bond strength mean values (in MPa) followed by distinct letters were significantly different. After 24 h, G5 = 21.12 A, G1 = 20.55 A, G4 = 19.19 AB, G2 = 14.22 B, and G3 = 8.44 C. After 12 months, G1 = 7.37 A, G5 = 5.61 AB, G4 = 4.97 B, G2 = 3.32 C, and G3 = 1.93 D. After 12 months of storage, all groups' bond strength significantly decreased. Conclusions: SBU and AU had bond strengths comparable to ZP after 24 h. No material resisted water degradation.

Effect of gastric acid on the surface roughness and bacterial adhesion of bulk-fill composite resins.

The purpose of this in vitro study was to evaluate the effect of gastric acid on the surface roughness and biofilm formation of bulk-fill composite resins. Twenty-seven samples of each composite resin were obtained: G1: Filtek Z250 XT (Z250), G2: Filtek Bulk Fill (FTK), G3: Tetric N-Ceram Bulk Fill (TTC), and G4: Aura Bulk Fill (AUR). The samples were quantitatively analyzed for surface roughness (Ra) using a roughness tester (n=15) and for biofilm formation (Cn) by the counting of colony-forming units (CFUs/mL) (n=9) in three different moments: after polishing (Ra0 and Cn0), after gastric acid immersion (Ra1 and Cn1), and after gastric acid and simulated tooth brushing (Ra2 and Cn2). Qualitative analysis through surface topography (n=3) was evaluated by scanning electron microscopy (SEM). Ra values were subjected to two-way repeated measures ANOVA, followed by Tukey's test. Cn values were subjected to Kruskal-Wallis analysis, followed by multiple comparisons analysis (α=0.05). Z250 and FTK showed significant increases in surface roughness at Ra1. There were fewer CFUs/mL on TTC and AUR in relation to those of Z250 and FTK for Cn0, Cn1 and Cn2. The SEM images showed that gastric acid increased the formation of cracks, exposure of fillers and micro cavities for all composite resins. After tooth brushing, the topographical changes were more evident but did not influence biofilm formation. The gastric acid promoted both degradation of the surfaces and bacterial adhesion for all composite resins.

Effect of gastric acid on the surface roughness and bacterial adhesion of bulk-fill composite resins

Abstract The purpose of this in vitro study was to evaluate the effect of gastric acid on the surface roughness and biofilm formation of bulk-fill composite resins. Twenty-seven samples of each composite resin were obtained: G1: Filtek Z250 XT (Z250), G2: Filtek Bulk Fill (FTK), G3: Tetric N-Ceram Bulk Fill (TTC), and G4: Aura Bulk Fill (AUR). The samples were quantitatively analyzed for surface roughness (Ra) using a roughness tester (n=15) and for biofilm formation (Cn) by the counting of colony-forming units (CFUs/mL) (n=9) in three different moments: after polishing (Ra0 and Cn0), after gastric acid immersion (Ra1 and Cn1), and after gastric acid and simulated tooth brushing (Ra2 and Cn2). Qualitative analysis through surface topography (n=3) was evaluated by scanning electron microscopy (SEM). Ra values were subjected to two-way repeated measures ANOVA, followed by Tukey's test. Cn values were subjected to Kruskal-Wallis analysis, followed by multiple comparisons analysis (α=0.05). Z250 and FTK showed significant increases in surface roughness at Ra1. There were fewer CFUs/mL on TTC and AUR in relation to those of Z250 and FTK for Cn0, Cn1 and Cn2. The SEM images showed that gastric acid increased the formation of cracks, exposure of fillers and micro cavities for all composite resins. After tooth brushing, the topographical changes were more evident but did not influence biofilm formation. The gastric acid promoted both degradation of the surfaces and bacterial adhesion for all composite resins.

Resumo O objetivo deste estudo in vitro foi avaliar o efeito do ácido gástrico na rugosidade superficial e na formação do biofilme nas resinas compostas de incremento único. Vinte e sete amostras de cada resina composta foram confeccionadas: G1: Filtek Z250 XT (Z250), G2: Filtek Bulk Fill (FTK), G3: Tetric N-Ceram Bulk Fill (TTC), and G4: Aura Bulk Fill (AUR). As amostras foram analisadas quantitativamente quanto à rugosidade da superfície (Ra) usando um rugosímetro (n=15) e para formação de biofilme (Cn) pela contagem de unidades formadoras de colônias (UFC/mL) (n=9) em três diferentes momentos: após polimento (Ra0 and Cn0), após imersão em ácido gástrico (Ra1 and Cn1), e após ácido gástrico e simulação de escovação (Ra2 and Cn2). Análise qualitative da topografia superficial (n=3) foi avaliada por meio de microscopia eletrônica de varredura (MEV). Os valores de Ra foram analisados pela ANOVA de duas vias para amostras pareadas, seguido do teste de Tukey. Os valores de Cn foram submetidos ao teste de Kruskal-Wallis, seguido da análise de comparações múltiplas (α=0,05). Z250 e FTK tiveram aumento significativo na rugosidade superficial em Ra1. Houve menos CFUs/mL para TTC e AUR em relação à Z250 e FTK em Cn0, Cn1 and Cn2. As imagens em MEV mostraram que o ácido gástrico aumentou a formação de fendas, exposição das partículas e mcrocavidades para todas as resinas compostas. Após escovação, as mudanças topográficas foram mais evidentes, mas não influenciou na formação do biofilme. O ácido gástrico promoveu degradação da superfície e adesão bacteriana para todas as resinas compostas.

Fracture Load of Monolithic CAD/CAM Ceramic Crowns Placed on Different Implant Abutments.

PURPOSE: To evaluate the fracture load of monolithic, single-tooth implant-supported crowns cemented on solid or Ti-base (Variobase C) abutments. MATERIALS AND METHODS: Besides abutment types (solid and Ti-base abutments), two ceramic systems (IPS e.max CAD and Zirconia inCoris ZI) and two occlusal thicknesses (0.5 and 1.5 mm) were also investigated in this study. In total, eight groups (n = 8) with 64 maxillary second premolar crowns were fabricated. All the crowns were cemented with resin cement, and the screw accesses in Ti-base groups were sealed with composite resin. After mechanical cycling, the specimens were submitted to fracture load test with the maximum force recorded in Newtons (N). Three-way analysis of variance (ANOVA) and Tukey post hoc test were used for statistical analyses (α = .05). RESULTS: Both the abutment type (P = .0001) and the ceramic system (P = .0001) significantly affected the results. Screw-access channels reduced the fracture load of crowns by half compared to those cemented on solid abutments. The 1.5-mm and 0.5-mm zirconia crowns placed on solid abutments had similar highest fracture loads, while the e.max CAD groups positioned on Ti-base abutments showed significantly lower values compared with other groups. CONCLUSION: The screw access reduces the resistance of crowns supported by Ti-base abutments compared to crowns cemented on solid abutments. The inCoris ZI showed a higher fracture load than the IPS e.max CAD regardless of the abutment type and thickness.

Immediate dentin sealing influences the fracture strength of ultrathin occlusal veneers made of a polymer-infiltrated ceramic network.

OBJECTIVE: The objective of this laboratory study was to assess the effect of immediate dentin sealing (IDS) on the fracture strength of teeth restored with ultrathin occlusal veneers made of a polymer-infiltrated ceramic network (PICN - Vita Enamic) with different fissure/cusp thicknesses. METHODS: Forty third molars were identically prepared in the dentin and allocated into four groups (n = 10) according to the fissure/cusp thickness of the occlusal veneers (0.3/0.6 mm or 0.6/0.9 mm) and the application or not of the IDS technique. Ten sound third molars were used as the control group. IDS was performed using a universal adhesive system (Single Bond Universal). The prepared teeth were scanned (Cerec software, version 4.1), and the occlusal veneers were shaped following the occlusal anatomy of a right second molar. Blocks of PICN were milled in the unit inLab MC XL. Following luting with Single Bond Universal and RelyX Ultimate, the fracture strength of the specimens was obtained with a universal testing machine. The fractures were classified as reparable or irreparable. Fracture strength values were analyzed with 2-way and 1-way ANOVA (α = 0.05) and Tukey's test. RESULTS: Only the IDS factor was significant (p = 0.001). The teeth restored with IDS (2875 ± 508 N) achieved significantly higher fracture strength than the teeth restored without IDS (2263 ± 354 N) (p < 0.05). The fracture strength of the specimens with IDS did not differ significantly from that of the sound teeth (3230 ± 620 N). The fractures were predominantly reparable. CONCLUSION: IDS improved the fracture strength of ultrathin occlusal veneers made of PICN.

Examining the effects of acid etching duration on the bond strength between two CAD/CAM materials and one composite resin.

This study aimed to evaluate the effect of three hydrofluoric acid (HF) etching periods on the micro-tensile bond strength between two CAD-CAM ceramic systems [Vita Suprinity (VS) and feldspathic CEREC blocs (CB)] and a composite resin. The ceramics were categorized into six groups based on the surface conditioning protocol used, as follows: G1: CB-HF 5% for 20 s; G2: CB-HF 5% for 40 s; G3: CB-HF 5% for 60 s; G4: VS-HF 5% for 20 s; G5: VS-HF 5% for 40 s; G6: VS-HF 5% for 60 s. Scotchbond Universal was applied onto the pretreated ceramic surfaces and covered with Filtek Z350 XT composite resin. After 24 h, the specimens were cut into microbars (n = 16) and a micro-tensile bond strength test (µTBS) was carried out. An optical microscope was used to examine the fractured microbars. The results showed statistically significant differences between the factors tested (p < 0.01). Moreover, the mean MPa of G1(17.27), G2(13.03), G3(12.82), G4(15.83), G5(21.66), and G6(14.50) was seen to significantly differ. The predominant failure type observed was adhesive, and all three periods of HF etching produced satisfactory bonding between the composite resin and CB. An etching time of 40 s provided the highest µTBS value for VS.

Fracture strength of teeth restored with milled ultrathin occlusal veneers made of polymer-infiltrated ceramic.

The purpose was to evaluate, in vitro, the fracture strength of teeth restored with 0.3- or 0.6-mm-thick occlusal veneers made of Vita Enamic® bonded to enamel or dentin. Fifty third molars were allocated into five groups (n=10): Group C - control (sound teeth); Group 0.3E - 0.3-mm-thick occlusal veneers bonded to enamel; Group 0.6E - 0.6-mm-thick occlusal veneers bonded to enamel; Group 0.3D - 0.3-mm-thick occlusal veneers bonded to dentin; Group 0.6D - 0.6-mm-thick occlusal veneers bonded to dentin. After luting with Single Bond Universal and Filtek Z-100, the samples were subjected to fracture strength test in a universal testing machine. The fractures were classified as irreparable and reparable. Data were analyzed with 2-way and 1-way ANOVA (α=.05) followed by Tukey's test. The teeth restored with 0.3-mm-thick occlusal veneers (2658 N) achieved significantly higher fracture strength compared to the teeth restored with 0.6-mm-thick occlusal veneers (2070 N) (p=0.017). The teeth restored with occlusal veneers bonded to enamel (2648 N) had significantly higher fracture strength compared to the teeth restored with occlusal veneers bonded to dentin (2049 N) (p=0.015). Group C (3355 N) and Group 0.3E (2965 N) did not differ significantly from each other, being the fracture strength significantly higher than the other groups (p<0.05). The fractures were predominantly reparable. The teeth restored with 0.3-mm-thick occlusal veneers achieved higher fracture strength compared to the teeth restored with 0.6-mm-thick occlusal veneers. The supporting substrate influenced the fracture strength, which was higher for the teeth restored with occlusal veneers bonded to enamel.

Fracture strength of teeth restored with milled ultrathin occlusal veneers made of polymer-infiltrated ceramic

Abstract The purpose was to evaluate, in vitro, the fracture strength of teeth restored with 0.3- or 0.6-mm-thick occlusal veneers made of Vita Enamic® bonded to enamel or dentin. Fifty third molars were allocated into five groups (n=10): Group C - control (sound teeth); Group 0.3E - 0.3-mm-thick occlusal veneers bonded to enamel; Group 0.6E - 0.6-mm-thick occlusal veneers bonded to enamel; Group 0.3D - 0.3-mm-thick occlusal veneers bonded to dentin; Group 0.6D - 0.6-mm-thick occlusal veneers bonded to dentin. After luting with Single Bond Universal and Filtek Z-100, the samples were subjected to fracture strength test in a universal testing machine. The fractures were classified as irreparable and reparable. Data were analyzed with 2-way and 1-way ANOVA (α=.05) followed by Tukey's test. The teeth restored with 0.3-mm-thick occlusal veneers (2658 N) achieved significantly higher fracture strength compared to the teeth restored with 0.6-mm-thick occlusal veneers (2070 N) (p=0.017). The teeth restored with occlusal veneers bonded to enamel (2648 N) had significantly higher fracture strength compared to the teeth restored with occlusal veneers bonded to dentin (2049 N) (p=0.015). Group C (3355 N) and Group 0.3E (2965 N) did not differ significantly from each other, being the fracture strength significantly higher than the other groups (p<0.05). The fractures were predominantly reparable. The teeth restored with 0.3-mm-thick occlusal veneers achieved higher fracture strength compared to the teeth restored with 0.6-mm-thick occlusal veneers. The supporting substrate influenced the fracture strength, which was higher for the teeth restored with occlusal veneers bonded to enamel.

Resumo O objetivo foi avaliar, in vitro, a resistência à fratura de dentes restaurados com facetas oclusais de Vita Enamic® com 0,3 ou o,6 mm de espessura e cimentadas em esmalte ou dentina. Cinquenta terceiros molares foram distribuídos em grupos (n=10): Grupo C-controle (dentes hígidos); Grupo 0,3E - facetas oclusais com 0,3 mm de espessura cimentados em esmalte; Grupo 0,6E - facetas com 0,6 mm de espessura cimentados em esmalte; Grupo 0,3D - facetas com 0,3 mm de espessura cimentados em dentina; Grupo 0,6D - facetas com 0,6 mm de espessura cimentados em dentina. Após cimentação com Single Bond Universal Filtek Z-100, as amostras foram submetidas ao teste de resistência à fratura em máquina de ensaio universal. As falhas foram classificadas em reparáveis e irreparáveis. Os resultados foram analisados pelo teste ANOVA de duas vias e uma via (α=0,05) seguido do teste de Tukey. Os dentes restaurados com facetas oclusais com 0,3 mm de espessura (2658 N) obtiveram resistência à fratura estatisticamente superior aos dentes restaurados com facetas com 0,6 mm (2070 N) (p=0.017). Os dentes restaurados com facetas cimentadas em esmalte (2648 N) tiveram resistência à fratura estatisticamente maior comparada aos dentes restaurados com facetas cimentadas em dentina (2049 N) (p=0.015). Grupo C (3355 N) e Grupo 0,3E (2965 N) não diferiram estatisticamente entre si, tendo resistência à fratura estatisticamente superior aos outros grupos (p<0.05). As fraturas foram predominantemente reparáveis. Os dentes restaurados com facetas oclusais com 0,3 mm de espessura apresentaram maior resistência à fratura comparada aos dentes restaurados com facetas com 0,6 mm. O substrato influenciou a resistência à fratura dos dentes restaurados com facetas oclusais, sendo maior quando cimentadas ao esmalte.

Properties of Acrylic Resin For CAD/CAM: A Systematic Review and Meta-Analysis of In Vitro Studies.

PURPOSE: This systematic review and meta-analysis of in vitro studies compared the prepolymerized acrylic resin used for CAD/CAM complete denture manufacturing versus the heat-polymerized acrylic resin for conventional complete dentures in terms of surface roughness, wettability, hardness and flexural strength. MATERIALS AND METHODS: An electronic search was performed in the PubMed, Embase, LILACS and Web of Science databases, without language or date restrictions. Gray literature and manual search tools were also used. The systematic review was carried out by two researchers independently, following the inclusion criteria: in vitro studies testing the CAD/CAM acrylic resin with a control group of heat-polymerized acrylic resin which compared at least one of the four material properties above. The meta-analysis was performed separately for each property, using a random effect model. RESULTS: Of the 914 studies found by means of search strategies, 698 were selected for the systematic review. After applying the eligibility criteria, only 17 articles were selected for the qualitative analysis in the systematic review; among these, 14 were included in the quantitative meta-analysis. The CAD/CAM prepolymerized acrylic resin in blocks had similar properties when compared to heat-polymerized acrylic resin in almost all outcome measures, with the exception of a statistically significant reduction in surface roughness. CONCLUSIONS: Based on the findings of this systematic review and meta-analysis, equally satisfactory results can be expected from dental prosthesis manufactured by the CAD/CAM system when compared to conventional ones, with the additional potential of reducing the pigmentation and attached microorganisms due to the reduced surface roughness of the prepolymerized resin.

Fracture load of CAD/CAM ultrathin occlusal veneers luted to enamel or dentin.

OBJECTIVES: To evaluate, in vitro, the fracture load of IPS e.max CAD occlusal veneers at thicknesses of either 0.3 or 0.6 mm luted to enamel or dentin. MATERIALS AND METHODS: Fifty human molars were randomly distributed into five groups (n = 10): G1 - healthy teeth (control); G2-0.3-mm-thick veneers luted to enamel; G3-0.6-mm-thick veneers luted to enamel; G4-0.3-mm-thick veneers luted to dentin; and G5-0.6-mm-thick veneers luted to dentin. After the luting procedures, the specimens were immersed in distilled water at 37°C for 24 hours and then subjected to mechanical loading (106 cycles at 200 N load). The specimens were subjected to a fracture load test in a universal testing machine. Two-way ANOVA and Tukey's test (α = 0.05) were used to analyze data. RESULTS: Only the thickness factor was significant (P = .002). Values of fracture load followed by distinct letters represent significant differences (P < .05): G1 (3204 N ± 730)ab ; G2 (3144 N ± 729)ab ; G3 (2489 N ± 606)b ; G4 (3591 N ± 776)a ; and G5 (2770 N ± 598)ab . CONCLUSION: IPS e.max ultrathin occlusal veneers luted to enamel or dentin obtained fracture load comparable to that of the healthy tooth. CLINICAL SIGNIFICANCE: IPS e.max CAD ultrathin occlusal veneers at 0.3 or 0.6-mm-thick seem to provide good perspectives in relation to the clinical use.

Interfacial Stress and Bond Strength of Bulk-Fill or Conventional Composite Resins to Dentin in Class II Restorations.

The aim was to evaluate the microtensile bond strength (mTBS) to dentin and interfacial stress in a class II cavity restored with bulk-fill or conventional composite resins and the margin interfaces. Vertical slot class II cavities in the mesial face, with the gingival end in dentin, were prepared in 72 third molars, being divided into groups (n=24): G1-Tetric N-Ceram; G2-Tetric N-Ceram Bulk-Fill; G3-SonicFill. Clearfil SE Bond adhesive system was used in all groups. Half of the teeth in each group (n=12) were submitted to thermo-mechanical cycling (TMC). Restored teeth (n=9) were cut perpendicular to obtain beams, which were submitted to a mTBS test in an EMIC machine. The cervical margins in dentin of the restored teeth (n=3) were assessed using SEM through epoxy resin replicas as well as the section of the restoration. Interfacial stresses after load application were calculated by 2D finite element analysis. The mTBS means-MPa followed by different letters represent statistical difference by ANOVA and Games-Howell's test (p<0.05): Without TMC: G1-15.68±6.10a; G2-10.08±5.21ab; G3-7.98±3.76b. With TMC: G1-9.70±5.52a; G2-5.79±1.42a; G3-4.37±1.87a. Interfacial stress (MPa) was 4.4 for SonicFill, 3.9 for Tetric N-Ceram, and 3.5 for Tetric N-Ceram Bulk-Fill. SEM images showed continuous margins for all composite resin restorations. It was possible to conclude that SonicFill obtained a slightly higher interfacial stress and lower bond strength to dentin in comparison with Tetric N-Ceram and Tetric N-Ceram Bulk-Fill. Continuous margin interfaces were obtained for Tetric N-Ceram, Tetric N-Ceram Bulk-Fill, and SonicFill. However, voids were observed in the SonicFill restorations.

Interfacial stress and bond strength of bulk-fill or conventional composite resins to dentin in class ii restorations

Abstract The aim was to evaluate the microtensile bond strength (mTBS) to dentin and interfacial stress in a class II cavity restored with bulk-fill or conventional composite resins and the margin interfaces. Vertical slot class II cavities in the mesial face, with the gingival end in dentin, were prepared in 72 third molars, being divided into groups (n=24): G1-Tetric N-Ceram; G2-Tetric N-Ceram Bulk-Fill; G3-SonicFill. Clearfil SE Bond adhesive system was used in all groups. Half of the teeth in each group (n=12) were submitted to thermo-mechanical cycling (TMC). Restored teeth (n=9) were cut perpendicular to obtain beams, which were submitted to a mTBS test in an EMIC machine. The cervical margins in dentin of the restored teeth (n=3) were assessed using SEM through epoxy resin replicas as well as the section of the restoration. Interfacial stresses after load application were calculated by 2D finite element analysis. The mTBS means-MPa followed by different letters represent statistical difference by ANOVA and Games-Howell's test (p<0.05): Without TMC: G1-15.68±6.10a; G2-10.08±5.21ab; G3-7.98±3.76b. With TMC: G1-9.70±5.52a; G2-5.79±1.42a; G3-4.37±1.87a. Interfacial stress (MPa) was 4.4 for SonicFill, 3.9 for Tetric N-Ceram, and 3.5 for Tetric N-Ceram Bulk-Fill. SEM images showed continuous margins for all composite resin restorations. It was possible to conclude that SonicFill obtained a slightly higher interfacial stress and lower bond strength to dentin in comparison with Tetric N-Ceram and Tetric N-Ceram Bulk-Fill. Continuous margin interfaces were obtained for Tetric N-Ceram, Tetric N-Ceram Bulk-Fill, and SonicFill. However, voids were observed in the SonicFill restorations.

Resumo O objetivo foi avaliar a resistência de união à microtração (RUμT) à dentina e o estresse interfacial em cavidades classe II restauradas com resina composta de incremento único ou convencional e as interfaces marginais. Cavidades classe II na face mesial, com margem gengival em dentina, foram confeccionadas em 72 terceiros molares, sendo divididos em grupos (n=24): Grupo 1-Tetric N-Ceram; Grupo 2- Tetric N-Ceram Bulk-Fill; Grupo 3- SonicFill. O Sistema adesivo Clearfil SE Bond foi usado em todos os grupos. Metade dos dentes de cada grupo (n=12) foram submetidos à ciclagem termo-mecânica (CTM). Os dentes restaurados (n=9) foram cortados perpendicularmente para obter palitos que foram submetidos ao teste de RµT na máquina-EMIC. As margens cervicais em dentina dos dentes restaurados (n=3) foram observados em microscopia eletrônica de varredura (MEV) por meio de réplicas em resina epoxy, assim como os cortes das restaurações. O estresse interfacial após a aplicação da carga foram calculadas por análise de elementos finitos 2D. As médias de RUμT-MPa seguidas de letras distintas apresentam diferença estatística de acordo com ANOVA e teste de Games-Howell (p<0,05): Antes da CTM: G1-15.68±6.10a; G2-10.08±5.21ab; G3-7.98±3.76b. Após CTM: G1-9.70±5.52a; G2-5.79±1.42a; G3-4.37±1.87a. O estresse interfacial (MPa) foi 4,4 para SonicFill, 3,9 para Tetric N-Ceram e 3,5 para Tetric N-Ceram Bulk-Fill. Imagens em MEV mostraram margens contínuas para todas as restaurações em resina composta. Foi possível concluir que o SonicFill obteve um estresse interfacial ligeiramente mais alto e menor resistência de união à dentina em comparação com o Tetric N-Ceram e o Tetric N-Ceram Bulk-Fill. Interfaces de margem contínua foram obtidas para Tetric N-Ceram, Tetric N-Ceram Bulk-Fill e SonicFill. Entretanto, espaços vazios foram observados nas restaurações do SonicFill.

Effect of Cariogenic Challenge on the Degradation of Adhesive-Dentin Interfaces.

The aim was to evaluate, in vitro, the influence of pH cycling on microtensile bond strength (µTBS) and percentage of nanoleakage (%NL) in the dentin-adhesive interface. Flat dentin surfaces were obtained in 56 extracted third molars. The teeth were randomly divided into four groups (n=14): G1- Single Bond Universal (etch-and-rinse mode); G2- Single Bond Universal (self-etch mode); G3- Scotchbond Multi-Purpose; G4- Clearfil SE Bond. A block of composite was built on the adhesive area. Eight tooth/resin sets were cut parallel to the tooth's long axis to obtain 48 beams (0.8 mm2) for each group. Half of the beams were submitted to four cycles of pH cycling (demineralizing solution for 6 h and remineralizing solution for 18 h). The samples were submitted to µTBS test in a universal testing machine. Six tooth/resin sets were cut parallel to the tooth's long axis to obtain three slices of the central region (1.0 mm thickness). Half of the slices were submitted to pH cycling. The nanoleakage methodology was applied to obtain the %NL at the adhesive interfaces. According to two-way ANOVA, the interaction between factors (adhesive system x storage) was significant (p=0.0001) for µTBS and %NL. After pH cycling, there was a significant decrease in µTBS and a significant increase in %NL for all adhesives. The adhesives applied in the self-etch mode obtained lower %NL, differing significantly from the etch-and-rinse adhesives. It was concluded that the pH cycling negatively influenced the µTBS and %NL for all adhesives evaluated. However, self-etch adhesives allowed less %NL.

Effect of cariogenic challenge on the degradation of adhesive-dentin interfaces

Abstract The aim was to evaluate, in vitro, the influence of pH cycling on microtensile bond strength (µTBS) and percentage of nanoleakage (%NL) in the dentin-adhesive interface. Flat dentin surfaces were obtained in 56 extracted third molars. The teeth were randomly divided into four groups (n=14): G1- Single Bond Universal (etch-and-rinse mode); G2- Single Bond Universal (self-etch mode); G3- Scotchbond Multi-Purpose; G4- Clearfil SE Bond. A block of composite was built on the adhesive area. Eight tooth/resin sets were cut parallel to the tooth's long axis to obtain 48 beams (0.8 mm2) for each group. Half of the beams were submitted to four cycles of pH cycling (demineralizing solution for 6 h and remineralizing solution for 18 h). The samples were submitted to µTBS test in a universal testing machine. Six tooth/resin sets were cut parallel to the tooth's long axis to obtain three slices of the central region (1.0 mm thickness). Half of the slices were submitted to pH cycling. The nanoleakage methodology was applied to obtain the %NL at the adhesive interfaces. According to two-way ANOVA, the interaction between factors (adhesive system x storage) was significant (p=0.0001) for µTBS and %NL. After pH cycling, there was a significant decrease in µTBS and a significant increase in %NL for all adhesives. The adhesives applied in the self-etch mode obtained lower %NL, differing significantly from the etch-and-rinse adhesives. It was concluded that the pH cycling negatively influenced the µTBS and %NL for all adhesives evaluated. However, self-etch adhesives allowed less %NL.

Resumo O objetivo foi avaliar, in vitro, a influência da ciclagem de pH na resistência de união à microtração (RUµT) e na porcentagem de nanoinfiltração (%NI) na interface dentina-adesivo. Superfícies planas em dentina foram obtidas em 56 terceiros molares. Os dentes foram aleatoriamente divididos em quatro grupos (n=14): G1- Single Bond Universal (condicionamento ácido prévio); G2- Single Bond Universal (autocondicionante); G3- Scotchbond Multi-Purpose; G4- Clearfil SE Bond. Bloco de resina composta foi construído sobre o adesivo. Oito conjuntos dente/resina foram cortados paralelamente ao longo eixo do dente para obter 48 palitos (0,8 mm2) para cada grupo. Metade dos palitos foi submetida a quatro ciclos de ciclagem de pH (solução desmineralizadora por 6 h e solução remineralizadora por 18 h). As amostras foram submetidas ao teste de RUµT em máquina de ensaio universal. Seis conjuntos dente/resina foram cortados paralelamente ao longo eixo para obter três fatias da região central (1,0 mm de espessura). Metade das fatias foi submetida à ciclagem de pH. A metodologia de nanoinfitração foi aplicada para obter a %NI nas interfaces. De acordo com ANOVA de duas vias, interação entre os fatores (adesivo x armazenamento) foi significativa (p=0.0001) para for RUµT e %NI. Após ciclagem de pH, houve redução significativa na RUµT e aumento significativo na %NI para todos adesivos. Os adesivos aplicados na técnica autocondicionante obtiveram menor %NI, diferindo significativamente dos adesivos com condicionamento ácido prévio. Concluiu-se que a ciclagem de pH influenciou negativamente a RUµT e a %NI para todos adesivos. Contudo, adesivos autocondicionantes permitiram menor %NI.

Effect of grape seed extract-containing phosphoric acid formulations on bonding to enamel and dentin.

The aim was to evaluate the effect of 2% grape seed extract (GSE) containing phosphoric acid (PhA) on the bond strength to enamel and dentin. The control group was 37% PhA. The following three PhA formulations with 2% GSE and 20% ethanol were obtained: GSE5 = 5% PhA; GSE10 = 10% PhA; and GSE20 = 20% PhA. The enamel and dentin surfaces of molars were etched with the acid solutions, followed by Scotchbond Multi-Purpose adhesive and composite resin application. The tensile bond strength (TBS) test evaluated the bond to enamel after 24 h, and the microtensile bond strength (µTBS) test evaluated the bond to dentin after 24 h and 12-month water storage. Etched enamel and dentin were observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. The TBS data were submitted to one-way ANOVA, while µTBS data were submitted to two-way ANOVA and Tukey's test (α = 0.05). The TBS (MPa) to enamel did not significantly differ among the control (48.1 ± 15.7), GSE5 (46.1 ± 9.6), GSE10 (49.8 ± 13.6) and GSE20 (44.1 ± 11.9) groups (p = 0.537). The µTBS (MPa) to dentin of the control (28.4 ± 14.4) and GSE20 (24.1 ± 8.1) groups were significantly higher than those of the GSE5 (16.8 ± 7.4) and GSE10 (17.5 ± 6.6) groups at 24 h (p < 0.006). After 12-month storage, only GSE5 (21.0 ± 7.8) and GSE10 (17.6 ± 8.0) did not show significantly decreased µTBS (p > 0.145). SEM micrographs showed a shallower enamel etching pattern for GSE5. AFM images showed the formation of collagenous globular structures for GSE5 and GSE10. The different acid solutions did not influence the TBS to enamel, and the µTBS to dentin was stable over time when dentin was etched with GSE5 and GSE10.

Effect of grape seed extract-containing phosphoric acid formulations on bonding to enamel and dentin

Abstract The aim was to evaluate the effect of 2% grape seed extract (GSE) containing phosphoric acid (PhA) on the bond strength to enamel and dentin. The control group was 37% PhA. The following three PhA formulations with 2% GSE and 20% ethanol were obtained: GSE5 = 5% PhA; GSE10 = 10% PhA; and GSE20 = 20% PhA. The enamel and dentin surfaces of molars were etched with the acid solutions, followed by Scotchbond Multi-Purpose adhesive and composite resin application. The tensile bond strength (TBS) test evaluated the bond to enamel after 24 h, and the microtensile bond strength (μTBS) test evaluated the bond to dentin after 24 h and 12-month water storage. Etched enamel and dentin were observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. The TBS data were submitted to one-way ANOVA, while µTBS data were submitted to two-way ANOVA and Tukey's test (α = 0.05). The TBS (MPa) to enamel did not significantly differ among the control (48.1 ± 15.7), GSE5 (46.1 ± 9.6), GSE10 (49.8 ± 13.6) and GSE20 (44.1 ± 11.9) groups (p = 0.537). The µTBS (MPa) to dentin of the control (28.4 ± 14.4) and GSE20 (24.1 ± 8.1) groups were significantly higher than those of the GSE5 (16.8 ± 7.4) and GSE10 (17.5 ± 6.6) groups at 24 h (p < 0.006). After 12-month storage, only GSE5 (21.0 ± 7.8) and GSE10 (17.6 ± 8.0) did not show significantly decreased μTBS (p > 0.145). SEM micrographs showed a shallower enamel etching pattern for GSE5. AFM images showed the formation of collagenous globular structures for GSE5 and GSE10. The different acid solutions did not influence the TBS to enamel, and the µTBS to dentin was stable over time when dentin was etched with GSE5 and GSE10.

Surface roughness of monolithic zirconia ceramic submitted to different polishing systems

Aim: The objective was to evaluate, quantitative and qualitative, the abrasive effect of three polishing systems on the monolithic zirconia ceramic. Methods: Thirty disk-shaped samples of Yttria Tetragonal Zirconia Polycrystal (Y-TZP) were randomly distributed in three groups (n = 10) according to polishing system: G1- Komet system (KO); G2 - CeraGloss system (CG); G3 - Eve Diacera system (EV). The surface roughness (Ra) was obtained with Rugosimeter in four different moments: a) initial - glaze sample (Ra0); b) after occlusal adjustment with diamond burs (Ra1); c) after polishing with the abrasive systems (Ra2); d) after polishing with felt disc and diamond paste (Ra3). Four additional samples were observed in scanning electron microscopy (SEM). Results: According to the Generalized Estimating Equation followed by the Bonferroni test (α = 0.05), the CG provided the lowest Ra2 (0.63 µm), not differing significantly from the KO (0.78 µm). The highest Ra2 was obtained with the EV (0.97 µm), which did not differ significantly from the KO. There was no statistical difference in Ra between the polishing with the abrasive systems (Ra2) and the final polishing with diamond paste (Ra3). SEM images showed that the polishing systems did not completely remove the grooves caused by the diamond burs during the occlusal adjustment. Conclusion: It was concluded that CG promoted smoother surface of the monolithic zirconia ceramic compared to EV, and intermediate smoothness was obtained with KO