A new method of adhesive system application improves the bond strength between fiber post and root dentin

Abstract This study evaluated a new method of adhesive system application on the bond strength between fiber post and root dentin using two adhesive systems. The canals of sixty bovine incisors were prepared and obturated. The roots were divided into six groups (n=10) according to the adhesive system (Clearfil SE - CSE and Single Bond Universal - SBU) and the application strategy (microbrush - MB; rotary brush - RB; and ultrasonic tip - US). The glass fiber posts were cemented with resin cement (RelyX ARC). The roots were sectioned perpendicularly to their long axis, and three slices per root were obtained. Previously to the push-out test, confocal laser scanning microscopy (CLSM) was performed to illustrate the interfacial adaptation of the cement to the root canal walls. Failure patterns were analyzed with 40x magnification. Shapiro-Wilk indicated a normal distribution of the data. The bond strength values were compared using one-way ANOVA and Tukey's tests. Student's T test analyzed the differences between the adhesive systems within each third and protocol. A significance level of 5% was used. CSE with RB showed higher mean bond strength values compared to MB (conventional technique) (P < 0.05). US application resulted in intermediate bond strength values for CSE (P > 0.05). The application of SBU using RB generated higher mean bond strength values compared to MB and US (P < 0.05). Adhesive failures were predominant (65.5%). CSE and SBU application with the new rotary brush improved the bond strength of fiber posts to root dentin compared to the conventional strategy.

Resumo Este estudo avaliou o efeito de um novo método para aplicação do sistema adesivo na resistência de união entre pino de fibra e dentina radicular usando dois sistemas adesivos. Os canais de sessenta incisivos bovinos foram preparados e obturados. As raízes foram divididas em seis grupos (n=10) de acordo com o sistema adesivo (Clearfil SE - CSE e Single Bond Universal - SBU) e com a estratégia de aplicação (microbrush - MB, escova rotatória - RB e inserto ultrassônico - US). Os pinos de fibra foram cimentados utilizando cimento resinoso (RelyX ARC). As raízes foram seccionadas perpendicularmente ao seu longo eixo e três fatias foram obtidas. Previamente ao teste de push-out, foi realizada microscopia de varredura confocal a laser para ilustrar a adaptação interfacial do cimento às paredes do canal radicular. Os padrões de falha foram analisados com magnificação de 40x. O teste de Shapiro-Wilk indicou distribuição normal dos dados. Os valores de resistência de união foram comparados usando o teste ANOVA de uma via e post hoc de Tukey. As diferenças entre os sistemas adesivos em cada terço e de acordo com cada protocolo foram analisadas pelo teste T de Student. O nível de significância foi de 5%. CSE aplicado com RB apresentou maiores valores médios de resistência de união do que quando aplicado com MB (técnica convencional) (P<0,05). Aplicação com US apresentou valores intermediários de resistência de união para o CSE (P>0,05). A aplicação do SBU utilizando RB gerou maiores valores médios de resistência de união comparados com MB e US (P<0,05). Falhas adesivas foram predominantes (65,5%). A aplicação do CSE e SBU com a nova escova rotatória melhorou a resistência de união dos pinos de fibra à dentina radicular comparados com a estratégia convencional.

Effect of irrigation protocols on smear layer removal, bond strength and nanoleakage of fiber posts using a self-adhesive resin cement.

Objectives: This study aimed to investigate the effect of the application method of 2% chlorhexidine (CHX) and its influence on the adhesion of fiberglass posts cemented with a self-adhesive resin cement. Materials and Methods: Sixty human mandibular premolars were endodontically treated and divided into 5 groups (n = 12), according to the canal irrigant and its application method: 2 groups with conventional syringe irrigation (CSI)-2.5% sodium hypochlorite (NaOCl) (control) and 2% CHX- and 3 groups with 2% CHX irrigation/activation-by passive ultrasonic irrigation (PUI), Easy Clean file, and XP-Endo Finisher file. Two roots per group were evaluated for smear layer (SL) removal by scanning electron microscopy. For other roots, fiber posts were luted using a self-adhesive resin cement. The roots were sectioned into 6 slices for push-out bond strength (BS) (7/group) and nanoleakage (NL) (3/group). Data from SL removal were submitted to Kruskal-Wallis and Student-Newman-Keuls tests (α = 0.05). Data from BS and NL were evaluated by 2-way analysis of variance and Tukey's test (α = 0.05). Results: For SL removal and BS, the CHX irrigation/activation promoted better values than CSI with CHX (p < 0.05), but it was not significantly different from CSI with NaOCl (p > 0.05). For NL, the lowest values were obtained by the chlorhexidine irrigation/activation groups (p < 0.05). Conclusions: Active 2% CHX irrigation can be used to improve the post space cleaning and adhesion before fiber post cementation with self-adhesive resin cements.

Bond Strength and Failure Mode of Glass Fiber Posts with Different Surface Treatments Prior to Silanization: An In Vitro Comparative Study.

Aim: The use of chemical agents in the surface treatment of glass fiber posts can improve their bond strength to the root canal. The aim of this study was to assess the bond strength and failure mode of glass fiber posts that received different surface treatments prior to silanization. Materials and Methods: In this cross-sectional and in vitro experimental study, 50 human lower premolar roots were randomly divided into five groups and subsequently prepared to receive the cementation of a fiberglass post prior to silanization. They were distributed as group 1 (with 24% hydrogen peroxide), group 2 (with 37% phosphoric acid), group 3 (with 1.23% acidulated phosphate fluoride for 2 minutes), group 4 (with 1.23% acidulated phosphate fluoride for 6 minutes), and group 5 (without pretreatment). After cementation, the roots were sectioned into two discs for each cervical, middle, and apical region. Bond strength was assessed using the push out technique. Adhesive, mixed, and cohesive failure modes were also assessed. For data analysis, ANOVA and Tukey's post hoc tests were used, as well as Pearson's chi-square test. A significance of P < 0.05 was considered in all statistical analyses. Results: When comparing the bond strength of root regions, significant differences were obtained in groups pretreated with phosphoric acid (P = 0.018) and acidulated phosphate fluoride for 2 and 6 minutes (P = 0.001 and P = 0.000, respectively). Furthermore, significant differences were obtained between posts treated only with silane and those that received phosphoric acid pretreatment (P = 0.006) and acidulated phosphate fluoride for 6 minutes (P = 0.001). Significant association of mixed failure mode was observed with hydrogen peroxide (P = 0.014) and phosphoric acid (P = 0.006) pretreatments. Cohesive failure was significantly associated with acidulated phosphate fluoride pretreatment for 2 minutes (P = 0.032) and with posts that did not receive treatment prior to silanization (P = 0.000). Conclusion: Posts treated only with silane and pretreated with hydrogen peroxide and acidulated phosphate fluoride for 2 minutes presented significantly higher bond strength with respect to those pretreated with phosphoric acid and acidulated phosphate fluoride for 6 minutes. However, acidulated phosphate fluoride for 2 minutes and silane were associated with a better bonding type.

Comparing Techniques for Removing Fiber Endodontic Posts: A Systematic Review.

AIM: This systematic review aimed to establish the available techniques for fiber post removal, pointing out where each method stands out evaluating its advantages, and where they fall short indicating the possible harmful effects. MATERIALS AND METHODS: This systematic review was registered in PROSPERO (CRD42020193799). A broad search of the electronic databases PubMed, Web of Science, Scopus, and Virtual Health Library was carried out before April 27, 2020, for in vitro studies about techniques for removing fiber posts luted with resin cements of endodontically treated teeth. The methodological quality of included studies was evaluated based on the critical assessment tool for in vitro studies. RESULTS: Thirteen articles were selected and included after applying the inclusion and exclusion criteria. All included studies received an assessment of methodological quality between high and moderate. Most studies used ultrasonic inserts as a strategy to remove fiber posts, manufactured removal kits and drills were also widely used, only one study evaluated the removal capacity of the Er:YAG laser. Ultrasonic inserts seem to lead to a greater working time for removal of the fiber post, tend to generate significant volume changes in the root structure and increase the temperature on the root canal and clean the root canal walls further. CONCLUSION: Although the results tend to show greater agility in removing fiber posts with manufactured removal kits and the ultrasonic inserts seem to work better in removing fiber remains and luting agent, there is still no consensus in the literature as to which technique is the best. CLINICAL SIGNIFICANCE: In some cases, clinicians may be faced with the need to remove fiber posts in order to regain access to the root canal due to the need for endodontic retreatment which directly implies the search for the most appropriate removal technique. How to cite this article: Purger LO, Tavares SJO, Martinez RLCH, et al. Comparing Techniques for Removing Fiber Endodontic Posts: A Systematic Review. J Contemp Dent Pract 2021;22(5):587-595.

Effect of different root dentin pretreatment protocols on the bond strength of fiber posts cemented with core buildup material / Efeito de diferentes protocolos de pré tratamento de dentinas radiculares na força de adesão de pinos de fibra cimentados com material de núcleo de preenchimento

Objective: The purpose of the study was to evaluate the push out bond strength of fiber posts -after cementaion with core build up material and dentin pretreatment using different adhesive protocolsin different root regions. Material and Methods: 28 endodonticaly treated human premolars were divided into 4 groups. The post spaces were treated with 1 of 4 different dentin bonding protocols: total etch light cured adhesive, solobond m; total etch dual cured adhesive, Excite f DSC; self-etching light cured adhesive, single bond universal; or selfetching dual cured adhesive, futura bond dc. Fiber posts, were luted with dual cured core material. The roots were cut into 2-mm-thick sections, in cervical, middle, and apical regions. Push-out tests were performed with a universal testing machine, and bond strength values (MPa) were calculated. Data were analyzed with 1- and 2-way analysis of variance and Tukey multiple comparison tests (a=.05). Failure modes were examined under stereo microscope. Results: The highest mean bond strength values were obtained for self-etch dual cured adhesive, (9.69 MPa). The Total etch light cured adhesive (2.81 MPa) showed the lowest bond strength. Self-etch light-polymerized and total etch dual-polymerized adhesives provided similar bond strengths (5.37, 5.72 respectively). The regional bond strength values were reduced significantly in apical post space (P<0.01). The most predominant failure type was mixed failure followed by adhesive failure. Conclusion: Dentin pretreatment using self-etch dual cured adhesives prior to fiber posts cementation offers a high bond strength. While using total-etch light cured adhesives is not recommended due to the low bonding quality.(AU)

Objetivo: O objetivo do estudo foi avaliar a força de adesão dos pinos de fibra após o cimentação com material de núcleo e o pré-tratamento da dentina utilizando diferentes protocolos adesivos em diferentes regiões radiculares. Material e Métodos: 28 pré-molares humanos tratados endodonticamente foram divididos em 4 grupos. Os condutos foram tratados com 1 de 4 diferentes protocolos de união à dentina: adesivo fotopolimerizável total, solobond m; adesivo de polimerização dual de condicionamento total, Excite f DSC; adesivo fotopolimerizável autocondicionante, Single Bond universal; ou adesivo de dupla curado autocondicionante, futura bond dc. Núcleos de fibra, foram cimentados com material resinoso e polimerizados. As raízes foram cortadas em seções de 2 mm de espessura, nas regiões cervical, média e apical. Testes de push-out foram realizados com uma máquina de testes universal, e os valores de resistência de união (MPa) foram calculados. Os dados foram analisados com análise de variância de 1 e 2 fatores e testes de comparação múltipla de Tukey (a = 0,05). Modos de falha foram examinados sob estéreo-microscópio. Resultados: Os valores médios mais elevados de resistência adesiva foram obtidos para o adesivo dual autocondicionante (9,69 MPa). O adesivo fotopolimerizável Total etch (2,81 MPa) apresentou a menor resistência de união. Os adesivos autocondicionantes fotopolimerizáveis e os de condicionamento tal duais, proporcionaram forças de adesão semelhantes (5,37, 5,72, respectivamente). Os valores de força de união regional foram significativamente reduzidos na região apical (P<0,01). O tipo de falha mais predominante foi falha mista seguida de falha adesiva. Conclusão: O pré-tratamento com dentina utilizando adesivos duais autocondicionantes antes da cimentação dos pinos de fibra oferece uma alta resistência de união. Enquanto que os adesivos de condicionamento total fotopolimerizáveis não sforam recomendados devido à baixa qualidade da adesão proporcionada. (AU)

Performance of Post-retained Single Crowns: A Systematic Review of Related Risk Factors.

INTRODUCTION: Numerous factors may influence the survival/success of post-retained restorations of endodontically treated teeth (ETT). The aim of this review was to assess the influence of the number of remaining coronal walls, the use or disuse of posts, and their type on the clinical performance of these restorations. METHODS: Randomized controlled trials and controlled clinical trials for ETT restored with a combination of post/crown or no post/crown were searched for in MEDLINE, Embase, and the Cochrane Library. Two authors independently reviewed all identified titles and abstracts for eligibility. Tables were generated to summarize the included studies, and reports of randomized trials were assessed for bias using the Cochrane risk of bias tool. RESULTS: Nine articles were identified as meeting the inclusion criteria. Teeth without ferrule presented the highest values of variation of success/survival (0%-97%), whereas teeth with remaining coronal walls (1, 2, 3, or 4 walls with ferrule) presented lower variation. The use of posts with a high elastic modulus success/survival ranged between 71.8% and 100%, whereas posts with a low elastic modulus ranged between 28.5% and 100%. The survival of crowns without posts varied between 0% and 100%. The poor performance of posts with a low elastic modulus and without posts was associated with the absence of ferrule and the preservation of only 1 coronal wall. CONCLUSIONS: The restoration of ETT should focus on the maintenance of the coronal structure. Until more studies with longer follow-up periods are available, posts with a high elastic modulus appear to present with better performance when restoring ETT with no ferrule.

Influence of the Resin Cement Thickness on the Push-Out Bond Strength of Glass Fiber Posts

Abstract The objective of the present study was to evaluate the influence of resin cement thickness on the bond strength of prefabricated and customized glass fiber posts after storage in distilled water. Thirty human uniradicular roots were treated endodontically. The roots were divided into 3 groups: THIN (thin cement layer) - post space preparation with #0.5 drill and cementation of #0.5 post; THICK (thick cement layer) - post space preparation with #1 drill and cementation of #0.5 post; and CUSTOM (customized cement layer) - post space preparation with #1 drill and cementation of a customized post (#0.5 glass fiber posts customized with resin composite). All posts were luted with self-adhesive resin cement. The push-out test was carried out after storage for 24 h and 90 days in distilled water at 37 °C. The data were analyzed with three-way ANOVA and Tukey's test (a=0.05). Bond strengths were significantly higher for CUSTOM (9.37 MPa), than for THIN (7.85 MPa) and THICK (7.07 MPa), which were statistically similar. Considering the thirds, the bond strength varied in the sequence: apical (7.13 MPa) < middle (8.22 MPa) = coronal (8.94 MPa). Bond strength for 24 h storage was significantly higher (8.80 MPa) than for 90-day storage (7.40 MPa). It may be concluded that the thickness of resin cement influenced the bond strength of glass fiber posts. The customized posts presented higher bond strength. Storage in water for 90 days affected negatively the values of bond strength, especially for thick cement layers in the apical third.

Resumo O objetivo deste estudo foi avaliar a influência da espessura da linha de cimento na resistência de união de pinos de fibra de vidro após armazenamento em água destilada. Trinta dentes humanos hígidos unirradiculares tiveram os canais tratados endodonticamente. As raízes foram distribuídas em três grupos: THIN (linha de cimento fina): conduto preparado com broca 0,5 e cimentação de pino 0,5; THICK (linha de cimento espessa): conduto preparado com broca 1 e cimentação de pino 0,5; e CUSTOM (linha de cimento personalizada): conduto preparado com broca 1 e cimentação de pino personalizada (pino 0,5 personalizado com resina composta). Os pinos foram cimentados com cimento auto-adesivo. Após armazenamento das raízes em água destilada a 37 °C por 24 h e 90 dias, o teste de cisalhamento por extrusão push-out foi realizado. Os resultados foram analisados estatisticamente por ANOVA a três fatores e teste de Tukey (a=0,05). A resistência de união foi significativamente maior para CUSTOM (9,37 MPa), do que para THIN (7,85 MPa) e THICK (7,07 MPa), que foram semelhantes entre si. Considerando-se os terços radiculares, a resistência de união variou na sequência: apical (7,13 MPa) < médio (8,22 MPa) = coronal (8,94 MPa). A resistência de união após 24 h de armazenamento em água foi significativamente maior (8,80 MPa) do que para 90 dias (7,40 MPa). Pode-se concluir que houve influência da espessura da linha de cimento na resistência de união de pinos de fibra de vidro, sendo que o uso de pinos personalizados apresentou maiores valores de resistência de união. O armazenamento em água por 90 dias afetou negativamente os valores de resistência de união, especialmente no terço apical, no grupo com linha de cimento mais espessa.

Push-out Bond Strength of Glass Fiber Posts Cemented in Weakened Roots with Different Luting Agents.

AIM: To evaluate the push-out bond strength (BS) of direct anatomic posts (DAPs) and conventional fiber posts (CFPs) cemented with different luting agents in different thirds of flared root canals. MATERIALS AND METHODS: A total of 60 human single-rooted canine teeth were transversally sectioned 16 mm from the radicular apex. After endodontic treatment, canals were flared with diamond burs. Samples were divided into six groups according to post type and luting agent: DAP and RelyX U100 (RXU); DAP and RelyX ARC (RXA); DAP and RelyX Luting 2 (RXL); CFP and RXU; CFP and RXA; CFP and RXL. Roots were sectioned transversely into six 1-mm-thick slices. The push-out test was performed and failure modes were observed. RESULTS: The DAP groups (7.23 ± 2.05) showed highest BS values (p < 0.05) when compared with CFP (5.93 ± 1.76). RelyX U100 (8.17 ± 1.70) showed higher BS values (p < 0.05) than RXA (6.46 ± 1.38), and RXL (5.10 ± 1.65) showed the lowest values. Bond strength on the apical third was statistically lower (p < 0.05) than that on the other thirds of the root canals. There was a predominance of adhesive failure for all groups. CONCLUSION: The DAPs improved retention in flared root canals, and RXU was the most effective luting agent. The apical third showed the lowest BS values. CLINICAL SIGNIFICANCE: The relining procedure of fiber posts with composite and the proper selection of luting resin cement are important for increasing bonding effectiveness in flared root canals.

Can cement film thickness influence bond strength and fracture resistance of fiber reinforced composite posts?

OBJECTIVES: This study compared the influence of cement film thickness (CFT) on bond strength (BS) and fracture resistance (FR) of fiber-reinforced composite (FRC) posts to root canal. MATERIALS AND METHODS: One hundred bovine incisors were used for BS and FR analysis (n = 10) and distributed into five experimental groups according to FRC post diameters (WhitePost DC no. 0.5, no. 1, no. 2, no. 3, no. 4), leading to five different CFTs. The canals were prepared using drill no. 4 provided by the post manufacturer and irrigated with 2.5% NaOCl. After conditioning (24% H2O2/5 min) and silanization, posts were cemented with resin cement. BS was evaluated using push-out test and FR using the compression test at 45°. A stereomicroscope was used to measure CFT and to analyze failure pattern. BS data were subjected to two-way ANOVA and Scheffé test for contrast (α = 0.05); FR data were subjected to one-way ANOVA. RESULTS: BS was significantly affected by CFT, as the most well-adapted post achieved the highest values (p < 0.05). BS was similar for all root thirds. CFT did not affect fracture resistance. No root fractures were observed. CONCLUSIONS: A FRC post well adapted to the root canal results in higher BS values. Different CFTs did not influence the FR of teeth restored with FRC posts. CLINICAL RELEVANCE: The results indicate that post retention is improved when a well-adapted post is used, although this has not been critical to fracture resistance.

Effects of sonic application of adhesive systems on bonding fiber posts to root canals.

INTRODUCTION: Luting posts inside the root canal is still a challenge because of the difficulty of bonding adhesive materials in the apical third of roots. This study evaluated the effect of the application mode of 3 simplified etch-and-rinse adhesives on the push-out bond strength (PBS), nanoleakage (NL), and in situ degree of conversion (DC) of fiber posts in the root canal. METHODS: The roots of human premolars were endodontically prepared and divided into 6 groups according to the combination of the main factors: adhesive (Ambar, FGM, Joinville, SC, Brazil; Adper Single Bond 2, 3MESPE, St Paul, MN; and XP Bond+self-cure activator, DeTrey Dentsply, Konstanz, Germany) and application mode (manual or sonic). The posts were cemented and the PBS tested at 0.5 mm/min. The NL was evaluated by scanning electron microscopy after the immersion of specimens in 50% silver nitrate. Micro-Raman spectroscopy was used to measure the in situ DC. Root third was also considered in the statistical evaluation. Data were analyzed by 3-way repeated measures analysis of variance and Tukey tests (5%). RESULTS: Under sonic application, the PBS and the in situ DC increased, whereas NL decreased significantly for all groups in the middle and apical thirds (P < .05). CONCLUSIONS: The application of simplified adhesives by sonic mode in the root canal is a feasible tool to increase the fiber post bond to root canals.

3D-microleakage assessment of adhesive interfaces: exploratory findings by µCT.

OBJECTIVES: To explore the feasibility of a 3D-microleakage protocol for the evaluation of various configurations of adhesive-tooth interfaces. METHODS: Three different kinds of specimens were prepared: (1) a Class-I composite restoration placed without any bonding to maximize gap formation at the interface; (2) a glass-fiber post cemented with a self-adhesive composite cement into a prepared root canal; and (3) inlay MOD composite restorations placed with either a 1-step self-adhesive or a 2-step etch-and-rinse composite cement. After silver-nitrate (AgNO3) infiltration, the specimens were scanned using a Skyscan 1172 X-ray microtomograph (µCT; Skyscan Bruker) at 100kV, 100µA and 7.8-9.5µm resolution. Projection images were reconstructed, after which maximum-intensity projections (MIPs) and 3D-volumetric renderings were produced. For the inlays, an additional conventional stereomicroscopic (SM) microleakage evaluation was accomplished after specimen sectioning. RESULTS: MIPs and 3D-renderings from specimens (1) and (2) revealed strongly varying microleakage patterns along the marginal gap/interface. For the specimens of setup (3), the high radiopacity of the 2-step composite cement hindered evaluation of the MIPs. MIP-microleakage patterns along the enamel margin of the restoration cemented with the 1-step composite cement corresponded well to the stereomicroscopic images. SIGNIFICANCE: The reported µCT-protocol revealed good sensitivity to detect AgNO3 infiltration at the adhesive-tooth interface when considerable microleakage was present. When microleakage was less apparent and spread in a more diffuse pattern, evaluation with µCT was less sensitive compared to stereomicroscopic evaluation.

Tensile Strength of Glass Fiber Posts Submitted to Different Surface Treatments

The aim of this in vitro study was to evaluate the tensile strength of glass fiber posts submitted to different surface treatments. Forty-eight maxillary canines had their crowns sectioned and root canals endodontically treated. The roots were embedded in acrylic resin and distributed into 3 groups according to the surface treatment: Group I: the posts were treated with silane agent for 30 s and adhesive; Group II: the posts were cleaned with alcohol before treatment with silane agent and adhesive; Group III: the posts were submitted to conditioning with 37% phosphoric acid for 30 s before treatment with silane agent and adhesive. Each group was divided into 2 subgroups for adhesive polymerization or not before insertion into the canal: A - adhesive was not light cured and B - adhesive was light cured. All posts were cemented with Panavia F and the samples were subjected to tensile strength test in a universal testing machine at crosshead speed of 1 mm/min. Data were submitted to one-way ANOVA and Tukey's test at 5% significance level. There was statistically significant difference (p<0.01) only between group GIII-B and groups GI-A and GI-B. No significant difference was found among the other groups (p>0.05). It was concluded that the products used for cleaning the posts influenced the retention regardless of adhesive light curing.

O objetivo deste estudo in vitro foi avaliar a resistência à tração de pinos de fibra de vidro submetidos a diferentes tratamentos de superfície. Quarenta e oito caninos superiores tiveram suas coroas seccionadas e as raízes tratadas endodonticamente. As raízes foram incluídas em resina acrílica e distribuídas em 3 grupos de acordo com o tratamento de superfície aplicado aos pinos: Grupo I: os pinos receberam agente silano por 30 s e adesivo; Grupo II: os pinos foram limpos com álcool e então receberam o agente silano e adesivo; Grupo III: os pinos foram submetidos ao condicionamento com ácido fosfórico a 37% por 30 s, seguido de agente silano e adesivo. Cada grupo foi dividido em 2 subgrupos de acordo com fotoativação do adesivo antes da inserção do pino no interior do canal: A – adesivo não foi fotoativado, B: o adesivo foi fotoativado. Todos os pinos foram cimentados com Panavia F e as amostras foram submetidas a teste de tração utilizando máquina universal de ensaios, com velocidade de 1 mm/min. Os dados obtidos foram submetidos à ANOVA a um critério e ao teste de Tukey com nível de significância de 5%. Houve diferença estatisticamente significante (p<0,01) entre o grupo GIII-B e os grupos GI-A e GI-B. Os demais grupos não apresentaram diferenças significantes entre si (p>0,05). Pode-se concluir que as substâncias utilizadas para a limpeza dos pinos interferiram em sua retenção, independente da fotopolimerização do adesivo.

Influence of ultrasound and irrigant solutions on the bond strength of glass fiber posts to root canal dentine / Influência do ultrassom e de soluções irrigantes na resistência de união de pinos de fibra de vidro à dentina do canal radicular

Objective: Assessment of the influence of the ultrasound and irrigant solutions on the bond strength (BS) of glass fiber posts. Material and Methods: Sixty-six roots of bovine teeth standardized at 16 mm were used. The roots were submitted to a biomechanical preparation up to size #80 Kerr file, with irrigation of 5 ml of saline solution at every file change and then filled. The canals underwent partial desobturation and were divided into 6 groups according to the irrigant solution and the use of ultrasound prior to the post cementation: S – saline solution; C – 2% chlorhexidine solution; H –2.5% sodium hypochlorite solution; US – saline solution + ultrasound; UC – 2% chlorhexidine solution + ultrasound; UH – 2.5% sodium hypochlorite solution + ultrasound. After the cementation of the posts, the specimens were cut into 3 slices of 2 mm of thickness, perpendicular to its long axis. The samples were submitted to push-out test with crosshead speed of 1 mm/min and load of 50kgf. The data obtained were submitted to ANOVA and Tukey test (level of significance of 5%). Results: Groups C 7.77(±1.8)a, UC 7.82(±1.6)a, S 7.33(±2.2)a, US 6.16(±2.3)a, H 5.43(±1.3)b, UH 5.01(±2.3)b values in Mpa. Only the irrigant solutions showed statistically significant differences (<0.05). Tukey test revealed smaller bond strength for the specimens treated with Sodium Hypochlorite (b). Conclusions: The ultrasound treatment did not show significant difference compared with the other groups; therefore, its use can be indicated prior to the cementation of glass fiber posts without damage to the bond strength. The sodium hypochlorite solution showed the smallest BS values compared with the other groups

Objetivo: Avaliação da influência do ultrassom e de soluções irrigadoras sobre a resistência de união (RU) de pinos de fibra de vidro. Material e Métodos: Utilizou-se 66 raízes de dentes bovinos, padronizadas em 16 mm. As raízes foram submetidas a preparo biomecânico até Lima Kerr #80, com irrigação de 5ml de solução salina fisiológica a cada troca de lima, e foi realizada a obturação. Os espécimes foram parcialmente desobturados e divididos em 6 grupos de acordo com a solução irrigadora e a utilização de ultrassom antes da cimentação do pino: S – solução salina; C – solução de clorexidina 2%; H – solução de hipoclorito de sódio 2,5%; US – solução salina + ultrassom; UC – solução de clorexidina 2% + ultrassom; UH – solução de hipoclorito de sódio 2,5% + ultrassom. Após a cimentação dos pinos, os espécimes foram seccionados em 3 fatias de 2 mm de espessura, perpendiculares ao seu longo eixo. Os corpos de prova foram submetidos ao teste de push-out com velocidade 1 mm/min e carga de 50 kgf. Os dados obtidos foram submetidos aos testes de ANOVA e Tukey (nível de significância 5%). Resultados: Grupos C 7,77(±1,8)a, UC 7,82(±1,6)a, S 7,33(±2,2)a, US 6,16(±2,3)a, H 5,43(±1,3)b, UH 5,01(±2,3)b valores em Mpa. Apenas as soluções irrigadoras apresentaram diferença estatística relevante (<0,05). Ao teste de Tukey, percebeu-se uma resistência menor aos espécimes tratados com Hipoclorito de Sódio (b). Conclusões: O tratamento com ultrassom não demonstrou diferença significante em relação aos demais grupos, portanto pode ser indicado antes da cimentação de pinos de fibra de vidro sem prejuízo na resistência de união. A solução de hipoclorito de sódio apresentou os menores valores de RU comparados aos demais grupos.

Pino anatômico com resina composta: relato de caso / Anatomic fiber post with composite resin: case report

O protocolo restaurador de dentes tratados endodonticamente é um desafio na odontologia adesiva atual, já que existem vários tipos de retentores intrarradiculares à disposição no mercado, com características ópticas e mecânicas que promovem um tratamento satisfatório. Dessa forma, a técnica de pino de fibra anatômico reembasado com resina composta direta torna-se eficiente para uso na clínica odontológica, especialmente em casos de condutos largos e tamanho reduzido de férula. Para tanto, o pino é limpo, aplica-se o silano e adesivo, além da resina composta não polimerizada para moldar o conduto radicular. Após, o pino é tratado novamente e cimentado com uma pequena espessura de linha de cimentação. Nesse artigo, o caso clinico abordará as etapas necessárias para a confecção do pino anatômico, além das estratégias de cimentação adesiva e a restauração com resina composta, trabalhando os conceitos da manutenção de uma delgada linha de cimentação para uma adequada reabilitação dental mantendo biomecânica e retenção do pino de fibra no interior do conduto radicular.

The restorative protocol for endodontically treated teeth is a challenge in adhesive dentistry, since there are several available types of intracanal posts with optical and mechanical characteristics that promotea satisfactory treatment. Thus, the anatomical fiber post technique is efficient for the use in dental practice, especially in cases of large root canals and small dental ferrules. So, the post is cleaned and then the silaneagent and adhesive system are applied, followed by the placement of the non-polymerized composite for root canal modeling. After this, the anatomical fiber post is treated again and followed by the luting procedure, showing a small cementation thickness. In this paper, the case report will address the necessary steps to realize the anatomical fiber post technique using strategies and adhesive cementation with composite resin restoration, working the concepts of maintaining a thin cement line and an adequate dental rehabilitation.

Ultrastructural evaluation of the hybrid layer after cementation of fiber posts using adhesive systems with different curing modes

This in vitro study evaluated the adhesive interface of intraradicular fiber glass posts and root dentin using scanning electron microscopy (SEM). Forty-eight single-rooted premolars were randomly divided into 6 groups consisting of chemical, dual, or light cured adhesive systems combined with either chemical or dual cure resin cements. Scanning electron microscopic analysis showed the best results for continuity, density and morphology of the hybrid layer and resin tags for the combination of a self-cure adhesive with self-cure cement resin, followed by a dual-cure adhesive with self-cure cement resin, and finally a light-cure adhesive with self-cure cement. For the dual-cure resin cement, the same relation may be observed. The apical third was the most critical region for evaluated the criteria for all combinations of materials (Kruskal-Wallis and Friedman tests; p<0.001). Generally, the simplification of steps in the adhesive system and the polymerization reaction of resin adhesives and cements produced a direct effect on the quality of the adhesive post/dentin substrate interface.

Este estudo in vitro avaliou as interfaces adesivas de pinos intra-radiculares de fibra de vidro e a dentina radicular utilizando microscópio eletrônico de varredura (MEV). Quarenta e oito pré-molares unirradiculares foram divididos ao acaso em seis grupos, compostos por sistemas adesivos de cura química, dual ou fotopolimerizável, associado com cimentos resinosos de polimerização química ou dual. As análises microscópicas mostraram a maior continuidade, densidade e morfologia da camada híbrida e prolongamentos resinosos para a associação entre adesivos e cimentos auto-polimerizáveis seguido pelo grupo do adesivo de dupla polimerização e cimento de resina auto-polimerizável, e finalmente pelo adesivo fotopolimerizável e cimento de resina auto-polimerizável . Para os cimentos resinosos de dupla polimerização a mesma relação pode ser observada. O terço apical mostrou ser o substrato mais crítico em relação aos critérios avaliados para todas as associações entre os materiais usados(testes de Kruskal-Wallis e Friedman p<0,001). De maneira geral, a simplificação dos passos do sistema adesivo e a reação de polimerização dos adesivos e cimentos resinosos produzem efeitos diretos na qualidade da interface adesivo pino/dentina.

Retenção em canais amplos de núcleos confeccionados por diferentes técnicas com pinos fibro resinosos / Retention of fiber posts made by diferent technics in enlarged root canals

O propósito desse trabalho foi verificar a retenção de pinos fibro resinosos cimentados em canais radiculares alargados simulando raízes extensamente comprometidas, fabricados por duas técnicas usadas para diminuir sua desadaptação; comparando-as ao pino fixado somente com cimento. Foram utilizados vinte e quatro raízes de dentes humanos unirradiculares, padronizadas com 15.0 mm de comprimento e 5.0 ± 0.3 mm de diâmetro. As raízes foram incluídas em resina acrílica e divididas em grupos de acordo com a técnica usada: grupo I - pino DC White Post no2 cimentado com sistema adesivo quimicamente ativado e com cimento resinoso dual; grupo II – mesmo pino reanatomizado com resina composta para copiar a anatomia do canal radicular, cimentado da mesma forma; e grupo III – mesmo pino associado a três pinos acessórios, cimentados do mesmo modo. O canal radicular teve seu diâmetro padronizado pela broca no2 para o pino DC em uma profundidade de 12.0 mm e alargado com uma broca tronco cônica em uma profundidade de 10.0 mm. As oito raízes de cada grupo foram seccionadas transversalmente em três discos de 3.0 mm, a partir da cervical para a execução de um ensaio de extrusão, descartando-se os últimos 2.0 mm, que serviram somente para centralizar o pino. Os valores de retenção foram registrados e tratados estatisticamente por ANOVA e pelo teste SNK (p<0.05). Diferenças significativas foram observadas entre três porções radiculares investigadas em todos os grupos, com os valores de retenção diminuindo da cervical para apical. A retenção na porção apical do grupo com pinos customizado com resina foi estatisticamente maior que na mesma região dos demais grupos. Nenhuma diferença foi encontrada entre o grupo com pinos acessórios e o grupo somente com pino e cimento nessa parte da raiz. Nenhuma diferença foi observada comparando as porções cervical e média dos diferentes grupos. Os tipos de falha após o teste de extrusão foram observados em microscópio eletrônico de ...

The aim of this study was to evaluate the retention of fiber posts cemented in enlarged root canals simulating compromised roots, fabricated with to two techniques used to minimize your desadptation; comparing it to posts fixed only with ciment. Twenty four single root human teeth standardized in 15.0mm length and 5.0 ± 0.3mm diameter were used. The roots were imbibed in acrylic resin and divided in groups according to the technique used: group I - DC White Post no2 cemented with quimically cured adhesive system and a dual cured resin cement; group II – the same post customized with composite resin to copy the root canal anatomy, cemented the same way; and group III – the same post associated with three accessory posts, cemented the same way. The root canals had their diameter standardized using a no2 DC post burs 12.0 mm deep and enlarged with a chamfer bur 10.0 mm deep. The eight roots of each group were transversely sectioned in three 3.0 mm diameter discs, starting from cervical to make the push out test, discarding the last 2.0mm used only to centralize the post. The retention values were registered and statistically treated with ANOVA and SNK tests (p<0.05). Significant differences were observed when comparing the three root portions of all groups investigated, with retention values decreasing from cervical to apical. The retention in apical portion of customized posts was statistically greater than the same parts of other groups. No differences were found between the group with accessory posts and only cemented posts in this root portion. No differences was observed comparing cervical e middle portions of different groups. The failure types after the push out test were observed in MEV with 200, 600 e 1000x magnification. They occurred exclusively between the post and the resin cement or the composite resin. A hybrid layer was more easily observed in the cervical and middle portions of the roots in all groups. This suggests that the ...

Regional bond strengths to root canal dentin of fiber posts luted with three cementation systems

This study evaluated the influence of the cementation system on the regional push-out bond strength and failure pattern of fiber posts to radicular dentin. The roots of 48 extracted human incisors were prepared and divided into 3 groups (n=16), according to the cementation system: AdperScotchbond Multi-Purpose + resin cement RelyX ARC (SBMP+ARC); Adper SingleBond 2 + RelyX ARC (SB+ARC) and; RelyX U100 self-adhesive resin cement (U100). The posts were cemented as per manufacturer’s instructions for each cementation system. After 1 week, the roots were sectioned transversely into 6 discs. Two discs were obtained from the cervical, middle and apical thirds and the push-out test was carried out. The failure pattern was examined on all debonded specimens. The data were analyzed by two-way repeated measures ANOVA and Tukey’s test. When U100 was used, no statistically significant difference (p>0.05) was observed among the different root regions. Statistically higher push-out bond strength values were detected in the cervical third for SBMP+ARC and SB+ARC (p<0.05). The U100 showed significantly more mixed failures than SBMP+ARC in the apical third (p<0.05). In conclusion, the self-adhesive cement RelyX U100 was the only cement not sensitive to the root canal region.

Esse estudo avaliou a influência do sistema de cimentação na resistência de união regional e os padrões de fratura de pinos de fibra à dentina radicular. As raízes de 48 incisivos humanos extraídos foram preparadas e divididas em 3 grupos (n=16) de acordo com o sistema de cimentação: AdperScotchbond Multi-Purpose + cimento resinoso RelyX ARC (SBMP+ARC); AdperSingle Bond 2 + RelyX ARC (SB+ARC) e cimento resinoso autoadesivo RelyX U100 (U100). Os pinos foram cimentados conforme as recomendações dos fabricantes para cada sistema de cimentação. Após uma semana, as raízes foram seccionadas transversalmente em 6 discos. Dois discos foram obtidos para os terços coronário, médio e apical e o teste de push-out foi realizado. O padrão de fratura foi avaliado em todos os espécimes. Os dados obtidos foram analisados através dos testes ANOVA dois fatores e Tukey. Quando o cimento U100 foi testado, não foram observadas diferenças significativas (p>0,05) entre as diferentes regiões radiculares. Valores de resistência de união significativamente superiores foram encontrados no terço coronário para SBMP+ARC e SB+ARC (p<0,05). O U100 apresentou significativamente mais fraturas mistas que o SBMP+ARC no terço apical (p<0,05). Conclui-se que o cimento resinoso autoadesivo RelyX U100 foi o único cimento não afetado pela região do canal radicular.

Retenção em canais amplos de núcleos confeccionados por diferentes técnicas com pinos fibro resinosos / Retention of fiber posts made by diferent technics in enlarged root canals

O propósito desse trabalho foi verificar a retenção de pinos fibro resinosos cimentados em canais radiculares alargados simulando raízes extensamente comprometidas, fabricados por duas técnicas usadas para diminuir sua desadaptação; comparando-as ao pino fixado somente com cimento. Foram utilizados vinte e quatro raízes de dentes humanos unirradiculares, padronizadas com 15.0 mm de comprimento e 5.0 ± 0.3 mm de diâmetro. As raízes foram incluídas em resina acrílica e divididas em grupos de acordo com a técnica usada: grupo I - pino DC White Post no2 cimentado com sistema adesivo quimicamente ativado e com cimento resinoso dual; grupo II – mesmo pino reanatomizado com resina composta para copiar a anatomia do canal radicular, cimentado da mesma forma; e grupo III – mesmo pino associado a três pinos acessórios, cimentados do mesmo modo. O canal radicular teve seu diâmetro padronizado pela broca no2 para o pino DC em uma profundidade de 12.0 mm e alargado com uma broca tronco cônica em uma profundidade de 10.0 mm. As oito raízes de cada grupo foram seccionadas transversalmente em três discos de 3.0 mm, a partir da cervical para a execução de um ensaio de extrusão, descartando-se os últimos 2.0 mm, que serviram somente para centralizar o pino. Os valores de retenção foram registrados e tratados estatisticamente por ANOVA e pelo teste SNK (p<0.05). Diferenças significativas foram observadas entre três porções radiculares investigadas em todos os grupos, com os valores de retenção diminuindo da cervical para apical. A retenção na porção apical do grupo com pinos customizado com resina foi estatisticamente maior que na mesma região dos demais grupos. Nenhuma diferença foi encontrada entre o grupo com pinos acessórios e o grupo somente com pino e cimento nessa parte da raiz. Nenhuma diferença foi observada comparando as porções cervical e média dos diferentes grupos. Os tipos de falha após o teste de extrusão foram observados em microscópio eletrônico de...

The aim of this study was to evaluate the retention of fiber posts cemented in enlarged root canals simulating compromised roots, fabricated with to two techniques used to minimize your desadptation; comparing it to posts fixed only with ciment. Twenty four single root human teeth standardized in 15.0mm length and 5.0 ± 0.3mm diameter were used. The roots were imbibed in acrylic resin and divided in groups according to the technique used: group I - DC White Post no2 cemented with quimically cured adhesive system and a dual cured resin cement; group II – the same post customized with composite resin to copy the root canal anatomy, cemented the same way; and group III – the same post associated with three accessory posts, cemented the same way. The root canals had their diameter standardized using a no2 DC post burs 12.0 mm deep and enlarged with a chamfer bur 10.0 mm deep. The eight roots of each group were transversely sectioned in three 3.0 mm diameter discs, starting from cervical to make the push out test, discarding the last 2.0mm used only to centralize the post. The retention values were registered and statistically treated with ANOVA and SNK tests (p<0.05). Significant differences were observed when comparing the three root portions of all groups investigated, with retention values decreasing from cervical to apical. The retention in apical portion of customized posts was statistically greater than the same parts of other groups. No differences were found between the group with accessory posts and only cemented posts in this root portion. No differences was observed comparing cervical e middle portions of different groups. The failure types after the push out test were observed in MEV with 200, 600 e 1000x magnification. They occurred exclusively between the post and the resin cement or the composite resin. A hybrid layer was more easily observed in the cervical and middle portions of the roots in all groups. This suggests that the...

Influência das soluções irrigadoras utilizadas em endodontia na resistência à tração de pinos de fibra de vidro fixados com cimentação adesiva / Influence of irrigating solutions used in endodontics in the tensile strength of fiberglass pins fastened with adhesive cementation

Materiais restauradores a base de resina são amplamente empregados na reconstrução de dentes tratados endodonticamente. Entretanto, algumas soluções utilizadas rotineiramente durante os procedimentos endodônticos podem ter efeito sobre a força de união de sistemas adesivos ao canal radicular. O objetivo deste estudo foi avaliar a influência de soluções irrigadoras utilizadas durante a limpeza e modelagem do sistema de canais radiculares na resistência à tração de pinos de fibra de vidro pré-fabricados fixados com cimentação adesiva. Foram utilizadas 50 raízes bovinas extraídas, distribuídas em cinco grupos de acordo com o agente irrigador empregado durante a instrumentação: grupo I - soro fisiológico; grupo II - hipoclorito de sódio (NaOCl) 1%; grupo III - NaOCl 2,5%; grupo IV - NaOCl 5,25%; grupo V - clorexidina gel 2% associada ao soro fisiológico. A obturação dos canais radiculares foi realizada com guta-percha associada ao cimento endodôntico AH Plus e os pinos de fibra de vidro cimentados por meio do sistema de fixação Clearfil SE Bond/RelyX ARC. Após sete dias de armazenamento em ambiente úmido a 37° C, os espécimes foram submetidos ao teste de resistência à tração em Máquina de Ensaios Universal - EMIC - modelo DL 2000, regulada a velocidade de 0,5 mm/min. Os valores obtidos em quilograma força (kgf) foram tabulados e submetidos à análise estatística (One-way ANOVA). Os resultados não mostraram diferenças estatisticamente significantes para o fator solução irrigadora (p > 0,70) com médias que variaram de 24,66 a 28,83 kgf, correspondentes aos grupos I e V, respectivamente. Concluiu-se, portanto, que as soluções irrigadoras testadas não influenciaram a resistência à tração do sistema de fixação utilizado para a cimentação de pinos intrarradiculares de fibra de vidro.

Use of resin-based restorative materials has become widely accepted for treatment of endodontically treated teeth. However, some solutions routinely used during endodontic treatment procedures may have an effect on bond strengths of adhesive materials to root canal dentin. The purpose of this study was to evaluate the influence of irrigant solutions used during root canals cleaning and shapping on tensile strength of prefabricated glass fiber posts luted with adhesive systems. Fifty extracted bovin roots were used. The specimens were divided into five groups according the irrigant solution used during mechanically enlargement: group I - saline solution; group II - sodium hypochloride (NaOCl) 1%; group III - NaOCl 2,5%; group IV - NaOCl 5,25%; group V - 2% chlorhexidine gluconate gel associated to saline solution. The root canals were filling using guta-percha and the sealer AH Plus and fiber posts lutting by Clearfil SE Bond/RelyX ARC. After storage in humidity at 37° C for seven days, the specimens were submitted to tensile strengths in a Universal Testing Machine - EMIC - model 2000, under 0,5 mm/min of velocity. The results expressed in kgf were schedule and submitted into statistical analysis (One-way ANOVA). They showed no significant statistical effect to the irrigant agent (p > 0,70) with mean ranging from 24,66 to 28,83 kgf, corresponding to groups I and V, respectively. Thus, it follows that the irrigant solutions didn’t affect the tensile bond strengths of fixation system employed by glass fiber posts lutting.

Influência do sistema de cimentação e do modo de ativação na resistência ao push-out de pinos de fibra de vidro / Influence of cementation system and activation mode on push-out bond strength of glass fiber posts

O objetivo deste estudo foi avaliar a influência do tipo de sistema de cimentação (condicionamento ácido total ou autoadesivo), do modo de ativação (autoativado ou dual), do terço do conduto radicular (cervical, médio ou apical) e da espessura do filme de cimento sobre a resistência de união de pinos de fibra de vidro cimentados em dentes humanos. Quarenta raízes foram incluídas em resina epóxi, submetidas a tratamento endodôntico e obturadas com guta percha e cimento endodôntico sem eugenol. Decorridos sete dias, os condutos foram preparados a uma profundidade de 10mm com brocas padronizadas do sistema dos pinos de fibra (WhitePost DC #2) e aleatoriamente divididos em 4 grupos, conforme o sistema de cimentação e o modo de ativação: (G1) RelyX ARC/Adper Scotchbond Multi-Purpose Plus (condicionamento ácido total), ativação dual, (G2) RelyX ARC/Adper Scotchbond Multi-Purpose Plus, autoativado, (G3) RelyX U100 (autoadesivo), dual e (G4) RelyX U100, autoativado. Após uma semana, cada raiz foi seccionada em máquina de corte, originando 6 fatias de 1 mm de espessura (n=60). Antes do ensaio de push-out cada fatia foi fotografada em ambas as faces, para determinação do raio dos pinos e da espessura do filme de cimento. Após o ensaio mecânico, novas imagens foram capturadas para determinação do modo de falha. Para automatizar a determinação da espessura de cimento, foi desenvolvida uma “macro” no software KS 400. Os dados foram estatisticamente analisados com ANOVA 3 fatores (resistência de união) e teste de Kruskall-Wallis (espessura do cimento). Comparações múltiplas foram realizadas com o teste Student-Newman-Keuls. Análise de regressão, modelo linear, foi empregada para verificar a correlação entre espessura do cimento e resistência de união. Todos os testes foram aplicados com α = 0,05. O fator cimento exerceu influência significativa para a resistência de união (p = 0,0402): o RelyX U100 apresentou a maior média. A ativação dual elevou os valores de ...

The aim of this study was to evaluate the influence of adhesive cementation system approach (total-etch or self-adhesive), activation mode (self-cure or dual-cure), canal third (cervical, middle or apical) and cement thickness on push-out bond strength of glass fiber post bonded on human roots. Forty roots were embebed in epoxy resin and endodontically treated (filled with guta percha and non-eugenol endodontic sealer). Following 7 days, the post spaces were prepared with low-speed post drills provided by the manufacturer (WhitePost DC #2, FGM) at a depth of 10 mm and the roots were randomly divided in 4 groups, according to cementation system and activations mode: (G1) RelyX ARC/Adper Scotchbond Multi-Purpose Plus (total-etch), dual-cure (G2) RelyX ARC/Adper Scotchbond Multi-Purpose Plus, self-cure, (G3) RelyX U100 (self-adhesive), dual-cure and (G4) RelyX U100, self-cure. After 7 days, each root was sectioned with water-cooled diamond blade, generating six 1-mm thickness slices (n=60). Before push-out bond strength test, digital images of both sides of the slices were captured with digital camera, in order to measure the post radius and the cement thickness. After mechanical test, new images were captured to evaluate the failure mode. A macro was developed in KS 400 software to speed and standardize the evaluation of cement thickness. Results were analyzed using three-way ANOVA (push-out) and Kruskall-Wallis test (cement thickness). Post-hoc multiple comparisons were performed using the Student-Newman-Keuls test. The correlation between resin cement thickness and bond strength was evaluated with regression analysis, linear model. All tests were performed with significance level set at 0.05. Push-out bond strength was significantly influenced by cement type (p= 0.0402): the RelyX U100 cement presented higher mean value. The dual-activated mode increased the bond strength in comparison to self-activated mode (p < 0.0001). Statically differences were ...