Effect of aging and cementation systems on the bond strength to root dentin after fiber post cementation.

This study evaluated the effect of aging and cementation of fiber posts using glass ionomer and resin cements on push-out bond strength, failure mode, and resin tag formation. One hundred and twenty bovine incisors were used. After post-space preparation, the specimens were randomly allocated into 12 groups (n = 10) according to the cementation system used: GC - GC Gold Label Luting & Lining); RL - RelyX Luting 2; MC - MaxCem Elite; RU - RelyX U200 and the aging periods (24 hours, 6 months, and 12 months). Slices from the cervical, middle, and apical thirds were obtained and analyzed by push-out bond strength test and confocal laser scanning microscopy. One-way ANOVA and Tukey's post-hoc test was used at a significance level of 5%. For the push-out bond strength test, no differences among GC, RU, and MC in the cervical and middle thirds were observed, regardless of the period of storage (P > 0.05). In the apical third, GC and RU showed similar bond strength but higher than other groups (P > 0.05). After 12 months, GC showed the highest bond strength (P < 0.05). Bond strength to post-space dentin decreased over time, regardless of the cementation system used. Cohesive failure was the most frequent, regardless of the period of storage, cementation system, and post-space third. Tag formation was similar among all groups. After 12 months, GC showed the highest bond strength values.

Effect of aging and cementation systems on the bond strength to root dentin after fiber post cementation

Abstract This study evaluated the effect of aging and cementation of fiber posts using glass ionomer and resin cements on push-out bond strength, failure mode, and resin tag formation. One hundred and twenty bovine incisors were used. After post-space preparation, the specimens were randomly allocated into 12 groups (n = 10) according to the cementation system used: GC - GC Gold Label Luting & Lining); RL - RelyX Luting 2; MC - MaxCem Elite; RU - RelyX U200 and the aging periods (24 hours, 6 months, and 12 months). Slices from the cervical, middle, and apical thirds were obtained and analyzed by push-out bond strength test and confocal laser scanning microscopy. One-way ANOVA and Tukey's post-hoc test was used at a significance level of 5%. For the push-out bond strength test, no differences among GC, RU, and MC in the cervical and middle thirds were observed, regardless of the period of storage (P > 0.05). In the apical third, GC and RU showed similar bond strength but higher than other groups (P > 0.05). After 12 months, GC showed the highest bond strength (P < 0.05). Bond strength to post-space dentin decreased over time, regardless of the cementation system used. Cohesive failure was the most frequent, regardless of the period of storage, cementation system, and post-space third. Tag formation was similar among all groups. After 12 months, GC showed the highest bond strength values.

Resumo Avaliar o efeito do envelhecimento e sistemas de cimentação usando ionômero de vidro e cimentos resinosos na resistência de união à dentina após a cimentação do pino de fibra. Cento e vinte incisivos bovinos foram utilizados. Após o preparo do pós-espaço, os corpos de prova foram distribuídos aleatoriamente em 12 grupos (n = 10) de acordo com o período de envelhecimento (24 horas, 6 meses e 12 meses) e o sistema de cimentação utilizado: GC - cimento de ionômero de vidro (GC Gold Label Cimentação e Revestimento); RL - RelyX Luting 2; MC - MaxCem Elite; RU - RelyX U200. Cortes dos terços cervical, médio e apical foram obtidos e analisados por teste de resistência de união push-out e microscopia confocal de varredura a laser. ANOVA one-way e teste de Tukey foi usado a um nível de significância de 5%. Para o teste de resistência de união, não foram observadas diferenças entre GC, RU e MC nos terços cervical e médio, independentemente do período de armazenamento (P > 0,05). No terço apical, GC e RU apresentaram resistência de união semelhante, porém superior aos demais grupos (P > 0,05). Após 12 meses, o GC apresentou a maior resistência de união (P < 0,05). A resistência de união à dentina no espaço para pino diminuiu ao longo do tempo, independentemente do sistema de cimentação utilizado. A formação de tags foi semelhante entre todos os grupos. Após 12 meses, o GC apresentou os maiores valores de resistência de união.

Addition of MTA in a salicylate-based resin root canal sealer to retrograde root-end filling

Aim To evaluate the flow, pH and calcium release of white MTA (WMTA), salicylate-based resin root canal sealer (Sealapex; SEAL) and SEAL containing 10 (SE10) or 20% (SE20) (w/w) of MTA. Methodology Flow test was realized according to ISO 6876 specification. The sealers samples (n= 10) were placed in polyethylene tubes and immersed in deionized water. After 24 hours and 7, 14, and 28 days, the water pH was determined with a pH meter, and calcium release was assessed by atomic absorption spectrophotometry. Results SEAL and WMTA showed respectively the highest and lowest flow rate when compared with the other materials (P<0.05). SE20 showed the highest pH value only in 24h and 7 days periods (p<0.05). In 14- and 28-days periods, SEAL showed the lowest pH value (p<0.05), but there are no differences between other groups (p>0.05). In all periods, WMTA and SEAL respectively showed the highest and lowest calcium release (p<0.05). Conclusions SE20 proves to be an association with better flow and handling than WMTA, with satisfactory potential for alkalinization and calcium release.

Effect of irrigation protocols on chemical smear layer formation over the post-space dentin.

This study evaluated the effect of irrigation protocols using 95% ethanol (ET) or 1% peracetic acid (PA) prior the use of 2% chlorhexidine (CHX) compared to distilled water (DW) on the chemical smear layer (CSL) formation and incidence of open dentin tubules at the apical, medium, and cervical third of the post-space dentin. Scanning electron microscopy (SEM) and electron dispersive spectroscopy (EDS) images were used. Forty bovine roots were endodontically treated. After, post-space preparation was performed and the roots were randomized in four groups (n = 10) according to the irrigation protocol: DW, CHX, CHX-ET and CHX-PA. The chemical composition of CSL and the incidence of open dentin tubules at the post-space thirds were evaluated by EDS (500× magnification) and SEM (2000× magnification) images, respectively. Data from chemical composition of CSL were descriptively analyzed, while the incidence of open dentin tubules was evaluated by scores and submitted to Kruskal-Wallis and Dunn test (p = .05). Cl, Bi, and Si were the chemical elements most found over the dentin after the irrigation with CHX and CHX-ET. Moreover, CHX and CHX-ET showed the highest incidence of CSL (p < .05), but without difference between them (p > .05), regardless of the post-space third. DW and CHX-PA showed similar incidence of CSL (p > .05). No difference on the incidence of open dentin tubules was found for any irrigation protocol and post-space third (p > .05). The use of 1% PA prior the post-space irrigation with CHX decrease the incidence of CSL. RESEARCH HIGHLIGHTS: The post-space irrigation with chlorhexidine results in the formation of chemical smear layer. Ethanol is not capable to remove the chemical smear layer. Peracetic acid is more effective to remove the chemical smear layer.

Benefícios e malefícios durante o procedimento de clareamento dental: revisão integrativa / Benefits and harms during the dental bleaching procedure: integrative review

Existem técnicas amplamente utilizadas na atualidade e diversos tipos de substâncias clareadoras em diferentes formas de apresentação que podem implicar no procedimento quando se é executado podendo trazer benefícios e/ou malefícios. O objetivo deste estudo foi realizar uma revisão integrativa da literatura acercar dos benefícios e/ou malefícios existente durante o processo de clareamento dental, nas bases de dados Lilacs e Pubmed, utilizando os descritores "Clareamento Dental"; "Odontologia baseada em evidências" e "Estética Dentária". Os critérios de inclusão foram artigos completos, nas línguas inglesa e portuguesa, indexados no período de 2010 a 2020. Após os artigos serem filtrados, 5.929 foram encontrados, e a partir destes, 9 artigos apresentaram informações que estavam relacionados com a temática a ser proposta. A partir da analise ficou explicito que a realização de um procedimento consciente de todas as etapas, com conhecimento da técnica e indicação é necessária para que se tenha sucesso(AU)

There are techniques used today and several types of whitening substances in different forms of presentation that may involve the procedure when it is possible to bring benefits and / or harms. The aim of this study was to carry out an integrative literature review about the benefits and / or harms that exist during the tooth whitening process, in the Lilacs and Pubmed databases, using the descriptors "Dental Whitening"; "Evidence-based dentistry" and "Dental Aesthetics". The inclusion criteria were complete articles, in English and Portuguese, indexed in the period from 2010 to 2020. After the articles were filtered, 5,929 were found, and from these, 9 articles presented information that was related to the theme to be proposed. From the analysis it was made explicit that the performance of a conscious procedure of all stages, with knowledge of the technique and indication is necessary for success(AU)

Effects of photodynamic therapy on the adhesive interface using two fiber posts cementation systems.

INTRODUCTION: Photodynamic therapy (PDT) can be employed for prosthetic space decontamination; however, its effects on adhesion of glass-fiber posts cementation systems are still unclear. PURPOSE: The aim of this study was to evaluate the effects of photodynamic therapy (PDT) on the adhesive interface between the dentin and different glass-fiber post cementation systems using a self-adhesive resin cement (RelyX U200) or a glass ionomer cement (Gold Label 1). METHOD: Forty human canine roots were endodontically-treated and prepared for fiber post. The roots were divided into four groups (n = 10), according to the PDT use and cementation protocol, as follow: G1- RelyX U200; G2: Gold Label 1; G3: PDT + RelyX U200; and G4: PDT + Gold Label 1. Afterwards, the roots were cross-sectioned and specimens from the cervical, middle and apical thirds of the post space were obtained and submitted to the push-out test. After that, the dentinal penetrability of the cementation protocol was assessed using laser confocal microscopy. CURRENT RESULTS: No significant differences were found in the bond strength values among the groups in all thirds (P > 0.05). G2 and G4 presented lower dentinal penetrability than the other groups, only in the cervical third (P < 0.05). CONCLUSION: Photodynamic therapy didn't present effects on the bonding interface between root dentin and fiber post cementation systems in both RelyX U200 and Gold Label 1, which were similar to each other.

Effects of Photodynamic Therapy on the Adhesive Interface of Fiber Posts Cementation Protocols.

INTRODUCTION: The aim of this study was to evaluate the effects of photodynamic therapy (PDT) on the bond strength and dentinal penetrability of cementation protocols using conventional resin cement (Relyx ARC; 3M ESPE, St Paul, MN) or self-adhesive (Relyx U200, 3M ESPE) after the glass fiber post cementation. METHODS: Forty human canine roots were endodontically treated and prepared for a fiber post. The roots were divided into 4 groups according to the cementation protocol and PDT use: conventional cement (CC), Relyx ARC; self-adhesive cement (SAC), Relyx U200 cement; PDT/CC, PDT + Relyx ARC; and PDT/SAC, PDT + Relyx U200. After cementation of the fiber posts, the roots were cross sectioned, and then specimens from the cervical, middle, and apical thirds of the prosthetic space were obtained. The specimens were submitted to the pushout test and dentinal penetration evaluation of the cementation protocol using laser confocal microscopy. RESULTS: PDT/CC presented the lowest bond strength to root dentin in the cervical third (P < .05). In the middle and apical thirds, all groups presented a similar bond strength (P > .05). PDT/CC presented the lowest dentinal penetration of the adhesive system in the cervical and apical thirds (P < .05). CONCLUSIONS: PDT presented negative effects on the bond strength to dentin in the cervical third after cementation using Relyx ARC and on the dentinal penetrability of the etch-and-rinse adhesive system in the cervical and apical thirds of the prosthetic space.