Resumo Introdução A resistência de união de um pino de fibra pode ser afetada por vários fatores, como o cimento endodôntico e o tempo de espera pós-endodontia. Objetivo Avaliar o efeito de diferentes cimentos endodônticos e dois tempos de espera pós-endodontia na resistência de união de pinos de fibra. Material e método Setenta e dois dentes bovinos foram tratados endodonticamente e obturados usando três cimentos endodônticos: à base de eugenol, à base de resina epóxia ou à base de mineral trióxido agregado. Os espécimes foram armazenados a 37 ° C por 24 horas ou por 30 meses. Após, os canais radiculares foram preparados para cimentação dos pinos de fibra usando o RelyX U200. Foram realizados testes de push-out e análise de falhas. Os dados foram analisados por análise de variância bidirecional e com o teste t. Resultado O cimento AH Plus obteve os maiores valores de resistência de união aos 30 meses pós-endodontia (11,26 Mpa) (p <0,05), no entanto, não houve diferença com o cimento Endofill no mesmo tempo. Os cimentos Endofill e MTA Fillapex não diferiram significativamente em seus efeitos, independentemente do tempo de espera pós-endodontia. Conclusão O cimento endodôntico utilizado e o tempo de espera pós-endodontia afetam a resistência adesiva dos pinos de fibra. A adesão aumenta significativamente quando o pino de fibra é cimentado 30 meses após a obturação do canal radicular, enquanto a adesão é reduzida ao cimentar imediatamente após o tratamento do canal radicular, principalmente para cimentos endodônticos à base de eugenol.

Abstract Introduction The resistance adhesive of a fiber post can be affected by several factors, such as the endodontic sealer and post-endodontic waiting time. Objective The aim of this study was to evaluate the effect of different endodontic sealers and two different post-endodontic waiting times on the bond strength of fiber posts. Material and method Seventy-two bovine teeth were endodontically treated and filled using three endodontic sealers: eugenol-based, epoxy resin-based, or mineral trioxide aggregate-based. The specimens were stored at 37°C for 24 hours or for 30 months. After the respective storage times, the root canals were prepared for luting fiber posts using RelyX U200. Push-out tests and analysis of failures were performed. The push-out data were analyzed by two-way analysis of variance to compare the effects of the endodontic sealer and with the t-test to compare the effects of post-endodontic waiting time. Result The AH Plus sealer yielded the highest bond strength values at 30 months post-endodontics (11.26 Mpa) (p < 0.05), however no had difference with Endofill sealer at the same time. Endofill and MTA Fillapex sealers did not differ significantly in their effects, irrespective of the post-endodontic waiting time. Conclusion In conclusion, the endodontic sealer used and post-endodontic waiting time affect the adhesive resistance of fiber posts. The adhesion increases significantly when the fiber post is cemented 30 months after the root canal filling, while the adhesion is reduced when cementing immediately after root canal treatment, in particular for eugenol-based endodontic sealers.

Resumo O objetivo deste estudo foi avaliar o efeito da irrigação do espaço preparado para o pino com NaOCl e CaOCl em diferentes concentrações na resistência adesiva de pinos cimentados com um cimento resinoso autoadesivo. Oitenta pré-molares foram seccionados 14 mm do ápice e endodonticamente tratado. As obturações foram parcialmente removidas. Os espécimes divididos randomicamente em 8 grupos (n=10) de acordo com o irrigante usado para irrigação do espaço preparado para pino: SF - soro fisiológico 0,9% (grupo controle); CHX - clorexidina 2%; NaOCl 1% - hipoclorito de sódio 1%; NaOCl 2,5% - hipoclorito de sódio 2,5%; NaOCl 5% - hipoclorito de sódio 5%; CaOCl 1% - hipoclorito de cálcio 1%; CaOCl 2,5% - hipoclorito de cálcio 2,5%; CaOCl 5% - hipoclorito de cálcio 5%. Para cada grupo, irrigação foi realizada com 2 mL de solução. O espaço preparado para pino foi seco com cone de papel absorvente (#80) e os pinos de fibra foram cimentados com cimento resinoso autoadesivo. Os espécimes foram seccionados perpendicularmente e o teste de push-out foi realizado. Microscopia óptica foi usada para analisar o padrão de falha. Os testes de ANOVA e Bonferroni analisaram os dados de resistência adesiva. NaOCl e CaOCl apresentaram similar resistência adesiva, independentemente da concentração usada para irrigar o espaço preparado para pino (p>0,05). SF apresentou os maiores valores de resistência adesiva (11,47 MPa) (p<0,05). Falhas adesivas na interface cimento/dentina foram predominantes (58,33%). Soro fisiológico deve ser o irrigante de escolha para irrigar o espaço preparado para pino antes da cimentação de pinos de fibra com cimentos resinosos autoadesivos. NaOCl e CaOCl afetam negativamente os valores de resistência adesiva.

Abstract The aim of this study was to evaluate the effect of post-space irrigation with NaOCl and CaOCl at different concentrations on the bond strength of posts cemented with a self-adhesive resin cement. Eighty premolars were sectioned 14 mm from the apex, and endodontically treated. The root canal filling was partially removed. Specimens were randomly assigned into 8 groups (n=10), according to the irrigant for post-space irrigation: SS - 0.9% saline solution (control group); CHX - 2% chlorhexidine; 1% NaOCl - 1% sodium hypochlorite; 2.5% NaOCl - 2.5% sodium hypochlorite; 5% NaOCl - 5% sodium hypochlorite; 1% CaOCl - 1% calcium hypochlorite; 2.5% CaOCl - 2.5% calcium hypochlorite; and 5% CaOCl - 5% calcium hypochlorite. For each group, irrigation was performed continuously with 2 ml of solution. The post-spaces were dried with paper points (#80), and glass fiber posts were cemented using a self-adhesive resin cement. The specimens were sectioned perpendicularly and the push-out test was performed. Optical microscopy was used to analyze the failure mode. ANOVA and Bonferroni tests analyzed the bond strength data. NaOCl and CaOCl presented similar bond strength regardless the concentration used to irrigate the post-space (p>0.05). SS showed the highest bond strength (11.47 MPa) (p<0.05). Adhesive failures at the cement/dentin interface were predominant (58.33%). Saline solution should be irrigant of choice to irrigate the post-space before fiber post cementation with self-adhesive resin cement. NaOCl and CaOCl negatively affect the bond strength values.

Abstract The aim of this systematic review was to compare the clinical performance and failure modes of teeth restored with intra-radicular retainers. A search was performed on PubMed/Medline, Central and ClinicalTrials databases for randomized clinical trials comparing clinical behavior and failures of at least two types of retainers. From 341 detected papers, 16 were selected for full-text analysis, of which 9 met the eligibility criteria. A manual search added 2 more studies, totalizing 11 studies that were included in this review. Evaluated retainers were fiber (prefabricated and customized) and metal (prefabricated and cast) posts, and follow-up ranged from 6 months to 10 years. Most studies showed good clinical behavior for evaluated intra-radicular retainers. Reported survival rates varied from 71 to 100% for fiber posts and 50 to 97.1% for metal posts. Studies found no difference in the survival among different metal posts and most studies found no difference between fiber and metal posts. Two studies also showed that remaining dentine height, number of walls and ferrule increased the longevity of the restored teeth. Failures of fiber posts were mainly due to post loss of retention, while metal post failures were mostly related to root fracture, post fracture and crown and/or post loss of retention. In conclusion, metal and fiber posts present similar clinical behavior at short to medium term follow-up. Remaining dental structure and ferrule increase the survival of restored pulpless teeth. Studies with longer follow-up are needed.

INTRODUÇÃO: a prevalência de bruxismo do sono (BS) na população infantil é tema de discussões na literatura.OBJETIVO: assim, este trabalho, por meio de uma revisão sistemática, teve como objetivo avaliar, de forma crítica, a prevalência de BS em crianças.MÉTODOS: foi feito um levantamento nas bases de pesquisa MEDLINE, Cochrane, Embase, PubMed, Lilacs e BBO, entre os anos de 2000 e fevereiro de 2013, com enfoque em estudos que avaliaram especificamente a prevalência de BS em crianças.RESULTADOS: após a aplicação dos critérios de inclusão, chegou-se a quatro estudos. Entre os artigos selecionados, as taxas de prevalência de BS variaram de 5,9% a 49,6%, sendo que essas variações apresentaram possíveis associações com os critérios diagnósticos para BS.CONCLUSÃO:verifica-se um número reduzido de estudos que apresentaram o objetivo primário de avaliar o BS em crianças, além de uma grande variação nas taxas de prevalência. Torna-se necessária a realização de novos estudos, baseados em métodos de evidências e com critérios diagnósticos padronizados e validados, para avaliar com maior precisão a prevalência do BS em crianças.

INTRODUCTION: Prevalence of sleep bruxism (SB) in children is subject to discussions in the literature.OBJECTIVE: This study is a systematic literature review aiming to critically assess the prevalence of SB in children.METHODS: Survey using the following research databases: MEDLINE, Cochrane, EMBASE, PubMed, Lilacs and BBO, from January 2000 to February 2013, focusing on studies specifically assessing the prevalence of SB in children.RESULTS: After applying the inclusion criteria, four studies were retrieved. Among the selected articles, the prevalence rates of SB ranged from 5.9% to 49.6%, and these variations showed possible associations with the diagnostic criteria used for SB.CONCLUSION: There is a small number of studies with the primary objective of assessing SB in children. Additionally, there was a wide variation in the prevalence of SB in children. Thus, further, evidence-based studies with standardized and validated diagnostic criteria are necessary to assess the prevalence of SB in children more accurately.

Objective: Considering that periodontal ligament simulation may influence the stress distribution over teeth restored with intraradicular retainers, this study aimed to assess the combined effect of mechanical cycling and periodontal ligament simulation on both the bond strength between fiber posts and root dentin and the fracture resistance of teeth restored using glass fiber posts. Material and Methods: Ninety roots were randomly distributed into 3 groups (n=10) (C-MC: control; P-MC: polyether; AS-MC: addition silicone) to test bond strength and 6 groups (n=10) (C: control; P: polyether; AS: addition silicone, without mechanical cycling, and C-MC, P-MC and AS-MC with mechanical cycling) to test fracture strength, according to the material used to simulate the periodontal ligament. For the bond strength test, fiber posts were cemented, cores were built, mechanical cycling was applied (2×106 cycles, 88 N, 2.2 Hz, and 45º incline), and the teeth cut into 3 slices (2 mm), which were then subjected to the push-out test at 1 mm/min. For the fracture strength test, fiber posts were cemented, cores were built, and half of the groups received mechanical cycling, followed by the compressive strength (45° to the long axis and 1 mm/min) performed on all groups. Results: Periodontal ligament simulation did not affect the bond strength (p=0.244) between post and dentin. Simulation of periodontal ligament (p=0.153) and application of mechanical cycling (p=0.97) did not affect fracture resistance. Conclusions: The materials used to simulate the periodontal ligament did not affect fracture or bond strength, therefore periodontal ligament simulation using the tested materials could be considered optional in the conditions of the study.

Este estudo objetivou avaliar a influência do tipo de cimento endodôntico (um cimento à base de resina de salicilato e dois cimentos endodônticos) e do tempo decorrido entre a obturação do conduto e a cimentação do pino de fibra na adesão de pinos de fibra à dentina radicular bovina. Sessenta dentes bovinos foram divididos em seis grupos (n=10), considerando um desenho experimental de dois fatores (3x2): cimento endodôntico em três níveis [à base de resina epóxica (AH Plus), eugenol (Endofill) e resina de salicilato e MTA (MTA Fillapex)] e o tempo para cimentação em dois níveis (cimentação imediata e 15 dias pós a obturação). Após cimentação do pino de fibra, fatias com 2 mm de espessura foram obtidas e submetidas ao teste de push-out. Os padrões de falha foram analisados em estereomicroscópio (40×) e classificados em: adesiva na interface cimento/dentina, adesiva cimento/pino, coesiva do cimento, coesiva do pino, coesiva da dentina e mista. Os dados foram analisados através dos testes de ANOVA a dois fatores e post hoc de Tukey (α=0,05). Quando os pinos de fibra foram cimentados imediatamente após a obturação dos condutos, a resistência adesiva foi similar, independentemente do tipo de cimento endodôntico. Entretanto, após 15 dias, os dentes obturados com cimento resinoso à base de resina epóxica apresentaram os maiores valores de resistência adesiva (p<0,05). Os valores de resistência adesiva do mesmo cimento nos diferentes tempos experimentais não foram alterados. O principal tipo de falha foi adesiva na interface cimento/dentina (89,4%). O tempo decorrido entre a obturação dos condutos e a cimentação do pino não influenciou a adesão do pino de fibra à dentina radicular. Por outro lado, o tipo de cimento endodôntico influencia a adesão entre dentina radicular e pinos de fibra.

This study aimed to assess the influence of the type of endodontic sealer (salicylate resin-based sealer vs. two endodontic sealers) and the time of fiber post cementation after root filling on the post adhesion to bovine root dentin. Sixty bovine roots were assigned to six groups (n=10), considering an experimental design with two factors (factorial 3x2): endodontic sealer factor in three levels [epoxy resin-based sealer (AH Plus), eugenol-based sealer (Endofill), and salicylate resin-based sealer plus mineral trioxide aggregate - MTA (MTA Fillapex)] and time for post cementation factor in two levels (immediate post cementation or 15 days after root canal filling). After post cementation, 2-mm-thick slices were produced and submitted to push-out test. The failure modes were analyzed under a 40× stereomicroscope and scored as: adhesive at cement/dentin interface; adhesive at cement/post interface; cement cohesive; post cohesive; dentin cohesive; or mixed. Data were analyzed using two-way ANOVA and Tukey's post-hoc tests (α=0.05). When the fiber posts were cemented immediately after the root canal filling, the bond strengths were similar, independent of the endodontic sealer type. However, after 15 days, the epoxy resin-based sealer presented higher bond strength than the other sealers (p<0.05). Comparison between each sealer in different experimental times did not reveal any differences. The main failure type was adhesive at dentin/cement interface (89.4%). The time elapsed between the root canal filling and post cementation has no influence on post/root dentin adhesion. On the contrary, the type of endodontic sealer can influence the adhesion between fiber posts and root dentin.

The wear resistance of denture teeth is important to the longevity of removable prostheses of edentulous patients. The ability of denture teeth to maintain a stable occlusal relationship over time may be influenced by this property. The purpose of this in vitro study was to evaluate the wear resistance of polymethyl methacrylate (PMMA) denture teeth based on their chemical composition when opposed by a ceramic antagonist. The maxillary canines (n=10) of 3 PMMA denture teeth (Trubyte Biotone, cross-linked PMMA; Trilux, highly cross-linked IPN (interpenetrating polymer network)-PMMA; and Vivodent, highly cross-linked PMMA) were secured in an in vitro 2-body wear-testing apparatus that produced sliding contact of the specimens (4.5 cycles/s, sliding distance of 20 mm, under 37°C running water) against glazed or airborne particle abraded ceramic. Wear resistance was measured as height loss (mm) under 300 g (sliding force) after 100,000 cycles, using a digital measuring microscope. Mean values were analyzed by 2-way ANOVA and Tukey's test (a=0.05). The wear of Trubyte Biotone (0.93 ± 0.14 mm) was significantly higher than that of both other types of teeth tested against abraded ceramic (p<0.05). The Vivodent tooth (0.64 ± 0.17 mm) exhibited the best wear resistance among the denture teeth tested against airborne particle abraded ceramic. There were no statistically significant differences (p>0.05) in wear among the 3 denture teeth evaluated against glazed ceramic. Trilux and Vivodent teeth tested against either glazed or airborne particle abraded ceramic did not differ significantly from each other (p<0.05). All teeth showed significantly more wear against airborne particle abraded ceramic than against glazed ceramic (p<0.05). In conclusion, the three types of PMMA denture teeth presented significantly different wear resistance against the abraded ceramic. The high-strength PMMA denture teeth were more wear-resistant than the conventional PMMA denture tooth.

A seleção adequada do agente cimentante é essencial para evitar falhas por perda de retenção em coroas retidas por núcleos. O objetivo deste estudo foi investigar a resistência à tração e o tipo de falha de pinos de fibra de vidro cimentados com diferentes materiais. Cimentaram-se pinos de fibra de vidro em 40 pré-molares inferiores, divididos em 4 grupos (n = 10): Grupo 1 - ionômero de vidro modificado por resina RelyX Luting; Grupo 2 - ionômero de vidro modificado por resina Fuji Plus; Grupo 3 - cimento resinoso RelyX ARC; Grupo 4 - cimento resinoso Enforce. Avaliaram-se os espécimes por teste de resistência à tração e análise por microscopia óptica para observação do tipo de falha. Compararam-se os valores de resistência à tração de cada grupo por análise de variância e teste de Tukey, sendo que o nível de significância estabelecido foi de 5%. Descreveram-se os tipos de falha na forma de porcentagens. Os valores de resistência à tração obtidos foram: Grupo 1 - 247,6 N; Grupo 2 - 256,7 N; Grupo 3 - 502,1 N; Grupo 4 - 477,3 N. Não houve diferença estatisticamente significativa entre os Grupos 1 e 2 ou entre os Grupos 3 e 4, porém os cimentos resinosos apresentaram valores de resistência à tração significativamente maiores do que os apresentados pelos cimentos ionoméricos. O Grupo 1 exibiu 70% de falhas coesivas, enquanto os Grupos 2, 3 e 4 apresentaram 70% a 80% de falhas adesivas na interface dentina-cimento. Concluiu-se que os cimentos resinosos e ionoméricos são capazes de proporcionar retenção clinicamente suficiente de pinos de fibras de vidro, e que os cimentos ionoméricos podem ser indicados principalmente quando houver dificuldades de aplicar técnicas adesivas.

Proper selection of the luting agent is fundamental to avoid failure due to lack of retention in post-retained crowns. The objective of this study was to investigate the tensile bond strength and failure mode of glass fiber posts luted with different cements. Glass fiber posts were luted in 40 mandibular premolars, divided into 4 groups (n = 10): Group 1 - resin-modified glass ionomer RelyX Luting; Group 2 - resin-modified glass ionomer Fuji Plus; Group 3 - resin cement RelyX ARC; Group 4 - resin cement Enforce. Specimens were assessed by tensile strength testing and light microscopy analysis for observation of failure mode. The tensile bond strength values of each group were compared by ANOVA and Tukey test. The significance level was set at 5%. The failure modes were described as percentages. The following tensile strength values were obtained: Group 1 - 247.6 N; Group 2 - 256.7 N; Group 3 - 502.1 N; Group 4 - 477.3 N. There was no statistically significant difference between Groups 1 and 2 or between Groups 3 and 4, yet the resin cements presented significantly higher tensile bond strength values than those presented by the glass ionomer cements. Group 1 displayed 70% of cohesive failures, whereas Groups 2, 3 and 4 exhibited 70% to 80% of adhesive failures at the dentin-cement interface. We concluded that resin cements and glass ionomer cements are able to provide clinically sufficient retention of glass fiber posts, and that glass ionomer cements may be especially indicated when the application of adhesive techniques is difficult.

OBJETIVO: O objetivo do estudo foi investigar a resistência à fratura sob compressão e padrão de falha de pré-molares tratados endodonticamente e clareados internamente por 21 dias com peróxido de carbamida a 37%, aplicando-se diferentes procedimentos restauradores. MATERIAL E MÉTODOS: O objetivo deste estudo foi investigar a resistência à fratura sob compressão e padrão de falha de pré-molares unirradiculares tratados endodonticamente e clareados internamente com peróxido de carbamida a 37%. Foram constituídos 6 grupos (n = 10): 1) dentes sem clareamento e câmara pulpar vedada com IRM; 2) dentes clareados e câmara pulpar vedada com IRM; 3) dentes clareados e câmara pulpar preenchida com resina composta fotopolimerizável; 4) dentes clareados, condutos preparados com 10mm, e preenchimento do conduto e câmara pulpar com IRM; 5) dentes clareados, condutos preparados com 10mm, cimentação de pino metálico pré-fabricado com fosfato de zinco e câmara pulpar vedada com resina composta; 6) dentes clareados, condutos preparados com 10mm, cimentação de pino de fibra de vidro com cimento resinoso e câmara pulpar vedada com resina composta. Após 24 horas de armazenamento em água destilada, os espécimes foram submetidos ao teste de resistência à fratura sob compressão em máquina de ensaios universal. RESULTADOS: Os seguintes valores foram encontrados: grupo 1 - 56,23kgf; grupo 2 - 48,96kgf; grupo 3 - 53,99kgf; grupo 4 - 45,72kgf; grupo 5 - 54,22kgf; grupo 6 - 60,12kgf. A Análise de Variância não mostrou diferença estatisticamente significante entre os grupos (p < .05), sugerindo que o clareamento interno com peróxido de carbamida a 37% não enfraqueceu os tecidos dentais. O maior número de fraturas desfavoráveis foi encontrado nos grupos 2 (50%), 4 (40%), e 5 (30%). O grupo 6 exibiu o padrão de falhas mais favorável. CONCLUSÃO: Os resultados sugerem que o clareamento interno com peróxido de carbamida a 37% não causou enfraquecimento importante dos dentes. Entre os dentes clareados, aqueles com restaurações temporárias de IRM ou com pinos metálicos mostraram o padrão mais desfavorável de fratura, enquanto o padrão de fratura mais favorável ocorreu em dentes restaurados com resina composta e pinos de fibras de vidro.

OBJECTIVE: This study investigated the compressive fracture strength and failure pattern in premolars submitted to endodontic treatment and internal bleaching with 37% carbamide peroxide for 21 days, with application of different restorative procedures. MATERIAL AND METHODS: Six groups were employed (n = 10): 1) non-bleached teeth and pulp chamber sealed with IRM; 2) bleached teeth and pulp chamber sealed with IRM; 3) bleached teeth and pulp chamber filled with light cured composite resin; 4) bleached teeth, root canals prepared at 10mm, filling of the root canal and pulp chamber with IRM; 5) bleached teeth, root canals prepared at 10mm, luting of prefabricated metallic post with zinc phosphate and pulp chamber sealed with composite resin; 6) bleached teeth, root canals prepared at 10mm, luting of glass fiber post with resin cement and pulp chamber sealed with composite resin. After 24-hour storage in distilled water, the specimens were submitted to compressive fracture strength testing in a universal testing machine. RESULTS: The following values were found: Group 1 - 56.23kgf; Group 2 - 48.96kgf; Group 3 - 53.99kgf; Group 4 - 45.72kgf; Group 5 - 54.22kgf; Group 6 - 60.12kgf. The analysis of variance did not reveal statistically significant difference between groups (p<0.05), suggesting that internal bleaching with 37% carbamide peroxide did not weaken the dental tissues. The largest number of unfavorable fractures was observed for Groups 2 (50%), 4 (40%), and 5 (30%). Group 6 exhibited the most favorable failure pattern. CONCLUSIONS: The results suggest that internal bleaching with 37% carbamide peroxide did not significantly weaken the teeth. Among the bleached teeth, those with temporary IRM restorations or metallic posts demonstrated the most unfavorable fracture pattern, whereas the most favorable fracture pattern occurred in teeth restored with composite resin and glass fiber posts.