ABSTRACT
BACKGROUND: At present, there is no uniform standard for the treatment time of chemical reagents for surface treatment of glass fiber posts. Therefore, studying the effect of treatment time of glass fiber post surface treatment reagents on the bond strength between fiber posts and resin cements is of great significance. OBJECTIVE: To evaluate the effect of two chemical agents on the bonding strength of glass fiber post and resin cement after surface pretreatment of glass-fiber posts at different times. METHODS: Forty-eight glass fiber posts were randomly divided into eight groups according to different surface treatment methods, six in each group. Group A received no special treatment; group B was treated with silanization for 1 minute; group C1 underwent a 30% hydrogen peroxide surface treatment for 5 minutes prior to 1-minute silanization; group C2underwent a 30% hydrogen peroxide surface treatment for 10minutes prior to 1-minutesilanization; group C3 underwent a 30% hydrogen peroxide surface treatment for 15 minutes prior to 1-minute silanization; group D1 underwent a 35% phosphoric acid surface treatment for 30 seconds prior to 1-minute silanization; group D2 underwent a 35% phosphoric acid surface treatment for 60 seconds prior to 1-minute silanization; group D3 underwent a 35% phosphoric acid surface treatment for 90 seconds prior to 1-minute silanization. The surface morphology of the treated glass fiber posts was observed under scanning electron microscope. The glass fiber post was bonded to the resin cement to form a cylindrical resin block and cut into a thin sample. The sheet was placed on a universal testing machine for micro-extrusion experiments. The failure mode of the specimens was observed under a stereomicroscope. RESULTS AND CONCLUSION: (1) Scanning electron microscope: the surface of the fiber post had different degrees of matrix dissolution and fiber bundle exposure after hydrogen peroxide and phosphoric acid treatment, but did not destroy the integrity of the fiber bundle. (2) Micro-extrusion experiments: the order of the bonding strength was as follows: group C3 > group C2 > group C1 > group D2 > groupD3 > groupD1> group B > group A, and there was significant difference between groups (P< 0.05) except for groups A and B, groups C2 andC3, and groups D2and D3. (3) Stereo microscope: the failure mode in the groups A and B was almost destruction in adhesion. The other six groups showed destruction in adhesion, but the cohesive failure and mixed failure were increased, and the failure mode changed from destruction in adhesion into cohesive failure and mixed failure. (4) These results indicate that the optimal treatment time of 30% hydrogen peroxide is 10 minutes, and the optimal treatment time of 35% phosphoric acid is 60 seconds. 30% hydrogen peroxide solution treatment of fiber post surface for 10 minutes has great clinical application value.
ABSTRACT
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.
Subject(s)
Humans , Animals , Male , Glass , Post and Core Technique , Resin CementsABSTRACT
Objective:To evaluate the micro-push-out bond strengths of prefabricated glass fiber posts with poly-dopamine functionalized to root dentin using resin cements, contrasted with silane treatment. Methods:In the study, 30 glass fiber posts were randomly divided into 3 groups ( 10 posts in each group) for different surface treatments. Group 1, treated with poly-dopa; Group 2, treated with silane coupling agent for 60s;Group 3, no surface treatment (Control group). The 30 extracted human, single-rooted teeth were endodontically treated and a 9 mm post space was prepared in each tooth with post drills provided by the manufacturer. Following post cementation, the specimens were stored in distilled water at 37 ℃ for 7 days. The micro-push-out bond strengths were tested using a universal testing machine (0. 5 mm/min), and the failure modes were examined with a stereomicroscope. The data of the three groups were statistically analyzed using the one-way ANOVA test(α= 0. 05). Results:The bond strengths were (7. 909 ± 1. 987) MPa for Group 1, (5. 906 ± 0. 620) MPa for Group 2, and 4. 678 ± 0. 910 MPa for Group 3 . The bond strength of poly-dopamine group was significantly higher than that of the silane group (P<0. 05). Conclusion: Contrasted with silane treatment, surface poly-dopamine functionaliza-tion was confirmed to be a more reliable method for improving the bond strength of resin luting agents to fiber posts.
ABSTRACT
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.
Subject(s)
Humans , Dental Stress Analysis/methods , Post and Core Technique/instrumentation , Root Canal Therapy , Bicuspid , Composite Resins/chemistry , Dental Cements/chemistry , Glass , In Vitro Techniques , Polymerization , Resin Cements/chemistry , Root Canal Filling Materials/chemistry , Surface Properties , Silanes/chemistry , Tensile StrengthABSTRACT
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.