Bond strength between composite repair and polymer-infiltrated ceramic-network material: Effect of different surface treatments.

OBJECTIVE: To evaluate the bond strength of a polymer-infiltrated ceramic-network (PICN) material and to composite repair after different surface treatments. MATERIALS AND METHODS: Eighteen blocks of the PICN material were obtained from CAD/CAM blocks, aged and randomly divided into 2 groups: 5% hydrofluoric acid (HF) or sandblasting with aluminum oxide particles (SAND). For each condition, three treatments were tested: silane (Sil), silane-containing adhesive (Ad), or silane + silane-containing adhesive (SilAd). The treated PICN surfaces were restored with composite resin. The microtensile bond strength test was performed in a universal testing machine, and data (MPa) were compared with two-way Analysis of variance (anova) and Tukey (α = 0.05). Roughness (Ra) and contact angle (CA) were obtained after HF and SAND conditions. RESULTS: The greatest bond strength values were obtained for the groups Sil and SilAd, for both HF and SAND pretreatments. The Ra values of SAND were statistically greater than HF. The CA generated by the adhesive on SAND surface was lower than HF surface. CONCLUSIONS: The use of silane improves the bond strength of the composite repair to PICN substrate compared to the single use of silane-containing adhesive. The HF pretreatment is most indicated when the silane-containing adhesive is applied alone. CLINICAL SIGNIFICANCE: Fractured PICN restorations can be repaired with composite resin, because the surface is treated with hydrofluoric acid or sandblasting followed by the individual use of silane.

Structural reinforcement and sealing ability of temporary fillings in premolar with class II mod cavities.

AIM: To evaluate the capability to reinforce tooth structure and sealing ability of temporary filling materials in premolars with MOD cavities. The hypothesis is that temporary filling materials can concomitantly prevent microleakage and increase fracture resistance. MATERIALS AND METHODS: Premolars received root canal treatment and MOD cavities. Cavities were restored with non- eugenol cement (CIM), glass ionomer cement (GIC) or light curable composite (BIO). Higid and without restoration were controls. Materials for flexual strength and teeth were tested for microleakage and compressive strength. RESULTS: GIC and Higid presented similar compressive strength, higher than other groups. Bio and GIC presented similar flexural strength higher than BIO. CIM and BIO showed similar micro- leakage lower than GIC. CONCLUSION: The hypothesis was rejected as filling materials tested failed to prevent microleakage and to increase fracture resistance concomitantly. CLINICAL SIGNIFICANCE: GIC may be considered to restore weakened teeth subjected to occlusal loads. BIO and CIM are better choices to microleakage in teeth not subjected to mechanical stresses.

Antimicrobial Efficacy and Dentin Collagen Damage Caused by Calcium Hypochlorite and Sodium Hypochlorite.

This study aimed to evaluate the antimicrobial activity of calcium hypochlorite (Ca (OCl)2) and sodium hypochlorite (NaOCl) using confocal laser scanning microscopy (CLSM) and dentin organic matrix alteration by picrosirius staining and light microscopy (LM). Samples of human extracted teeth were infected with Enterococcus faecalis by centrifugation of the bacterial suspension and were treated with Ca(OCl)2 or NaOCl at 0.5%, 2.5%, and 6% for 15, 30, and 60 seconds. CLSM and viability staining were used to quantitatively analyze the proportions of dead/live bacteria in the canal lumen and border of the root canal. The data were analyzed by ANOVA and Fisher test. For LM analysis, one hundred bovine teeth were randomly divided into 10 test groups (n=10): G1- Without treatment; G2- 17% EDTA; G3- 6% NaOCl; G4- 6% NaOCl + EDTA; G5- 0.5% Ca(OCl)2; G6- 0.5% Ca(OCl)2 + EDTA; G7- 2.5% Ca(OCl)2; G8- 2.5% Ca(OCl)2 + EDTA; G9- 6% Ca(OCl)2; G10- 6% Ca(OCl)2 + EDTA. The samples were fragmented and stained with Picrosirius. Data were analyzed by Kruskal-Wallis and Dunn (P<0.05). There was a strong correlation between the results of the canal lumen and the border of the root canal (r=0.962). Both hypochlorites at a concentration of 0.5% showed less microbial reduction compared to 2.5% and 6% (P<0.05). There was less antimicrobial activity at 15 seconds compared to 30 and 60 seconds (P<0.05). Ca(OCl)2 and NaOCl showed similar results at the same concentrations (P>0.05). In conclusion, Ca(OCl)2 caused fewer alterations to the dentin organic matrix at concentrations of 0.5% and 2.5%. Ca(OCl)2 presents antimicrobial activity similar to NaOCl, and collagen damage is concentration-dependent.

Glycolic acid: Characterization of a new final irrigant and effects on flexural strength and structural integrity of dentin.

The aim of this study was to characterize glycolic acid (GA) and examine its effects on powder and flexural strength of dentin. Particle size and energy-dispersive EDS in GA powder was performed for chemical analysis. Surface tension and pH levels of ethylenediaminetetraacetic acid (EDTA), citric acid (CA), and GA solutions were evaluated at different times and temperatures. Dentin powder and mineralized dentin beams were immersed for 1 min in EDTA, CA, or GA solutions and subjected to Fourier transform infrared spectroscopy for apatite/collagen ratio analysis and 3-point flexure test, respectively. GA showed the largest particle size (µm), and its surface tension was similar to that of EDTA and CA. Surface tension decreased in solutions of higher concentrations. GA showed pH stability at all times and temperatures evaluated. The apatite/collagen ratio reduced with increased GA concentrations, while flexural strength was not significantly affected by GA concentration. GA seems a good choice as a final irrigation solution after root canal preparation.

Effect of a new irrigant solution containing glycolic acid on smear layer removal and chemical/mechanical properties of dentin.

The objective of this study was to evaluate the effects of glycolic acid (GA) (with pH 1.2 and 5) and ethylenediaminetetraacetic acid (EDTA) on the chemical and mechanical properties of dentin to investigate the potential use of GA as final irrigant in the root canal therapy. Specifically, changes in microhardness, smear layer removal, erosion, mineral content distribution, apatite/collagen ratio and flexural strength of mineralized dentin treated with GA were assessed. Saline solution was used as a negative control. Knoop microhardness (KHN) was measured on the root canal lumen of root segments. Dentin beams were used for 3-point flexural strength (σ) test. Scanning electron microscopy (SEM) images of root sections were obtained for evaluation of smear layer removal and dentin erosion on root segments and energy dispersive X-ray spectroscopy (EDS) was used for mineral content distribution. The apatite/collagen ratio (A/C) in dentin powder were examined by Fourier transform infrared (FTIR) spectroscopy. KHN, σ and A/C results were statistically analyzed with ANOVA and Tukey tests (α = 0.05). Smear layer and dentin erosion scores were analyzed with Kruskal-Wallis and Dunn tests (α = 0.05). Root dentin treated with EDTA and GA presented similar KHN regardless of the pH (p > 0.05). However, KHN was significantly reduced in EDTA and GA groups when compared to control group (p<0.001). GA showed the same ability to remove the smear layer and to cause dentin erosion as EDTA. EDS results showed that the GA and EDTA solutions did not alter the dentin mineral content distribution. The apatite/collagen ratio reduced with all irrigant solution and was the lowest with GA pH 5 (p<0.001), while σ was not significantly affected by the experimental solutions (p = 0.559). It can be concluded that GA has similar ability to remove the smear layer than EDTA. GA does not affect negatively the chemical/mechanical properties and it does not increase dentin erosion. The use of GA with low pH seems to promote less change in collagen/apatite ratio, but further studies are needed to establish an ideal clinical protocol. Therefore, this study supports the potential use of GA as an alternative final irrigation solution for root canal preparation.

Antimicrobial Efficacy and Dentin Collagen Damage Caused by Calcium Hypochlorite and Sodium Hypochlorite

Abstract This study aimed to evaluate the antimicrobial activity of calcium hypochlorite (Ca (OCl)2) and sodium hypochlorite (NaOCl) using confocal laser scanning microscopy (CLSM) and dentin organic matrix alteration by picrosirius staining and light microscopy (LM). Samples of human extracted teeth were infected with Enterococcus faecalis by centrifugation of the bacterial suspension and were treated with Ca(OCl)2 or NaOCl at 0.5%, 2.5%, and 6% for 15, 30, and 60 seconds. CLSM and viability staining were used to quantitatively analyze the proportions of dead/live bacteria in the canal lumen and border of the root canal. The data were analyzed by ANOVA and Fisher test. For LM analysis, one hundred bovine teeth were randomly divided into 10 test groups (n=10): G1- Without treatment; G2- 17% EDTA; G3- 6% NaOCl; G4- 6% NaOCl + EDTA; G5- 0.5% Ca(OCl)2; G6- 0.5% Ca(OCl)2 + EDTA; G7- 2.5% Ca(OCl)2; G8- 2.5% Ca(OCl)2 + EDTA; G9- 6% Ca(OCl)2; G10- 6% Ca(OCl)2 + EDTA. The samples were fragmented and stained with Picrosirius. Data were analyzed by Kruskal-Wallis and Dunn (P<0.05). There was a strong correlation between the results of the canal lumen and the border of the root canal (r=0.962). Both hypochlorites at a concentration of 0.5% showed less microbial reduction compared to 2.5% and 6% (P<0.05). There was less antimicrobial activity at 15 seconds compared to 30 and 60 seconds (P<0.05). Ca(OCl)2 and NaOCl showed similar results at the same concentrations (P>0.05). In conclusion, Ca(OCl)2 caused fewer alterations to the dentin organic matrix at concentrations of 0.5% and 2.5%. Ca(OCl)2 presents antimicrobial activity similar to NaOCl, and collagen damage is concentration-dependent.

Resumo Este estudo teve como objetivo avaliar a atividade antimicrobiana do hipoclorito de cálcio (Ca(OCl)2) e do hipoclorito de sódio (NaOCl) usando a microscopia confocal a laser (MCVL) e a alteração da matriz orgânica da dentina por meio da coloração com picrosirius e microscopia óptica (MO). Amostras de dentes humanos extraídos foram infectados com Enterococcus faecalis por centrifugação da suspensão bacteriana. As amostras foram tratadas com Ca(OCl)2 ou NaOCl a 0,5%, 2,5% e 6% durante 15, 30 e 60 segundos. A MCVLe a coloração de viabilidade foram utilizadas para analisar quantitativamente as proporções de bactérias vivas/mortas no lúmen do canal e no bordo do canal radicular. Os dados foram analisados por ANOVA e teste de Fisher LSD. Para análise de MO, cem dentes bovinos foram divididos aleatoriamente em 10 grupos teste (n=10): G1- Sem tratamento; G2- 17% de EDTA; G3- 6% de NaOCl; G4- 6% de NaOCl + EDTA; G5- 0,5% de Ca(OCl)2; G6- 0,5% de Ca(OCl)2 + EDTA; G7- 2,5% de Ca(OCl)2; G8- 2,5% de Ca(OCl)2 + EDTA; G9- 6% de Ca(OCl)2; G10- 6% de Ca(OCl)2 + EDTA. As amostras foram fragmentadas e coradas com Picrosirius. Os dados foram analisados por Kruskal-Wallis e teste de Dunn (P<0,05). Houve uma forte correlação nos resultados do lúmen do canal e na borda do canal radicular (r=0,962). Ambos os hipocloritos, a uma concentração de 0,5%, mostraram menor redução microbiana em comparação com 2,5% e 6% (P<0,05). Houve menor atividade antimicrobiana aos 15 segundos em comparação com 30 e 60 segundos (P<0,05). Em conclusão, o Ca(OCl)2 e o NaOCl apresentaram resultados semelhantes nas mesmas concentrações (P>0,05). O Ca(OCl)2 causou menos alterações na matriz orgânica da dentina em concentrações de 0,5% e 2,5%. O Ca(OCl)2 apresenta atividade antimicrobiana semelhante ao NaOCl, e os danos ao colágeno dependem da concentraçã

Glycolic acid as the final irrigant in endodontics: Mechanical and cytotoxic effects.

The aim of this study was to investigate the effects of glycolic acid (GA) on the microhardness, roughness, dentin mineral content distribution; smear layer removal and cytotoxicity. One hundred human teeth were randomly divided into six groups: distilled water (control group), 17% EDTA, 10% citric acid (CA), 5% GA, 10% GA, and, 17% GA. Microhardness and roughness were measured in the canal lumen. Scanning electron microscopy (SEM) images (2000×) for smear layer removal evaluation; energy dispersive X-ray spectroscopy (EDS) for chemical analysis. Cell viability assay was made on fibroblast cells. The lowest microhardness and higher roughness were observed for 17% GA. GA showed the ability to remove the smear layer to a similar level as EDTA and CA, with no statistical difference between the concentrations used. GA and CA were cytotoxic in a dose-dependent manner. GA showed potential as an endodontic agent for final irrigation in root canal terapies.

Graphene Nanosheets to Improve Physico-Mechanical Properties of Bioactive Calcium Silicate Cements.

Bioactive calcium silicate cements are widely used to induce mineralization, to cement prosthetic parts, in the management of tooth perforations, and other areas. Nonetheless, they can present clinical disadvantages, such as long setting time and modest physico-mechanical properties. The objective of this work was to evaluate the potential of graphene nanosheets (GNS) to improve two bioactive cements. GNS were obtained via reduction of graphite oxide. GNS were mixed (1, 3, 5, and 7 wt %) with Biodentine (BIO) and Endocem Zr (ECZ), and the effects on setting time, hardness, push-out strength, pH profile, cell proliferation, and mineralization were evaluated. Statistics were performed with two-way ANOVA and Tukey test (α = 0.05). GNS has not interfered in the composition of the set cements as confirmed by Raman, FT-IR and XRD. GNS (1 and 3 wt %) shortened the setting time, increased hardness of both materials but decreased significantly the push-out strength of ECZ. pH was not affected but 1 wt % and 7 wt % to ECZ and 5 wt % to BIO increased the mineralization compared to the controls. In summary, GNS may be an alternative to improve the physico-mechanical properties and bioactivity of cements. Nonetheless, the use of GNS may not be advised for all materials when effective bonding is a concern.

Bond Strength between Fiber Posts and Root Dentin Treated with Natural Cross-linkers.

INTRODUCTION: The aim of this study was to investigate the effects of a proanthocyanidin-rich extract (grape seed extract [GSE]) on the bond strength and stability of the adhesion of fiber posts to the root dentine using 2 adhesive systems: a total-etch and a self-etch adhesive system. METHODS: Single-rooted human teeth were randomly divided into 6 groups: G1 (control), untreated + total-etch adhesive Adper Scotchbond Multi-Purpose (3M ESPE, St Paul, MN); G2, 6.5% GSE for 5 minutes + SB; G3, 10% GSE for 5 minutes + SB; and G4 to G6 groups were similar to previous ones; however, the self-etch adhesive system Clearfil SE Bond (Kuraray, Kurashiki, Japan) was used. Fiber posts were cemented with RelyX ARC (3M ESPE), and the specimens were immediately tested for push out or stored for 12 months. The bond strength means were analyzed by analysis of variance and Games-Howell post hoc tests (α = 0.05). Additionally, matrix metalloproteinase inhibition by 0.65%, 0.065%, and 0.0065% GSE was examined with gelatin zymography. RESULTS: The use of GSE did not affect immediate bond strength to dentin and contributed to preserve the bond strength after 12 months (P < .05) for both adhesives. The bond strength of SB was significantly higher than Clearfil SE Bond (P < .05). Gelatin zymography showed reduced matrix metalloproteinase activity when recombinant enzymes were incubated with both 0.65% and 0.065% GSE, with complete inhibition at the highest concentration. CONCLUSIONS: The pretreatment with GSE can be used as a natural alternative to improve bond strength stability of dentin-adhesive interfaces in root canals.

Use of standards in papers published in dental journals.

This study evaluated the use de standards in papers published in Brazilian and international dental journals. Papers published from January 2006 to December 2010 in the following journals were examined: Brazilian Dental Journal (BDJ), Brazilian Oral Research (BOR), Journal of Applied Oral Sciences (JAOS), Journal of Dental Research (JDR) and Dental Materials (DM). In addition to the title and type of study, issue, volume and year of publication, the following information was recorded from each paper: identification of any standard reported in the study; in case of no reported standard, indication if a standard could be used in the study. A total of 3,046 papers were examined, being 937 from DM, 936 from JDR, 489 from JAOS, 348 from BDJ, and 336 from BOR. Considering the papers that could use some standard, DM showed the highest percentage (24.9%) of reporting standards/paper, followed by JAOS (10.3%), BOR (10.1%), BDJ (6.3%) and JDR (2.4%), meaning for example that, from 936 papers examined from the JDR, 623 could use some standard but only 15 papers reported them. From all papers examined, 309 (10.1%) reported using some standard. The ISO standards were mostly reported (57.8%), followed by ASTM standards (23.7%) and 74 (18.5%) standards from other international organizations (e.g. ADA and CIE). Despite of the high impact factors of the selected dental journals, their published papers could use standards more often. This study should assist journal editors to encourage authors to consult and refer to available standards to support the scientific papers.

Use of standards in papers published in dental journals

This study evaluated the use de standards in papers published in Brazilian and international dental journals. Papers published from January 2006 to December 2010 in the following journals were examined: Brazilian Dental Journal (BDJ), Brazilian Oral Research (BOR), Journal of Applied Oral Sciences (JAOS), Journal of Dental Research (JDR) and Dental Materials (DM). In addition to the title and type of study, issue, volume and year of publication, the following information was recorded from each paper: identification of any standard reported in the study; in case of no reported standard, indication if a standard could be used in the study. A total of 3,046 papers were examined, being 937 from DM, 936 from JDR, 489 from JAOS, 348 from BDJ, and 336 from BOR. Considering the papers that could use some standard, DM showed the highest percentage (24.9%) of reporting standards/paper, followed by JAOS (10.3%), BOR (10.1%), BDJ (6.3%) and JDR (2.4%), meaning for example that, from 936 papers examined from the JDR, 623 could use some standard but only 15 papers reported them. From all papers examined, 309 (10.1%) reported using some standard. The ISO standards were mostly reported (57.8%), followed by ASTM standards (23.7%) and 74 (18.5%) standards from other international organizations (e.g. ADA and CIE). Despite of the high impact factors of the selected dental journals, their published papers could use standards more often. This study should assist journal editors to encourage authors to consult and refer to available standards to support the scientific papers.

Este estudo avaliou o uso de normas científicas em artigos de Odontologia publicados em periódicos brasileiros e internacionais. Trabalhos publicados de janeiro de 2006 a dezembro de 2010 foram examinados nas seguintes revistas: Brazilian Dental Journal (BDJ), Brazilian Oral Research (BOR); Journal of Applied Oral Science (JAOS), Journal of Dental Research (JDR) e Dental Materials (DM). Além do título, tipo de estudo, volume e ano de publicação, as seguintes informações foram registradas a partir de cada artigo: identificação de normas relatadas no estudo; em caso negativo, relatar se alguma norma poderia ser aplicada no estudo. Um total de 3.046 artigos foi examinado como segue: 937 no DM, 936 no JDR, 489 no JAOS, 348 BDJ e 336 no BOR. Considerando os artigos que poderiam usar alguma norma, o DM apresentou o maior percentual (24,9%) de normas/artigos relatados, seguido pelo JAOS (10,3%), BOR (10,1%), BDJ (6,3%) e JDR (2,4%), o que significa que de 936 trabalhos analisados do JDR, 623 poderiam ter usado alguma norma, mas apenas 15 relataram o uso. De todos os trabalhos examinados, 309 (10,1%) estudos relataram alguma norma. As normas ISO foram relatadas na maior parte (57,8%), seguido pelas normas ASTM (23,7%) e 74 (18,5%) feitas por outras organizações internacionais (por exemplo, ADA e CIE). Apesar do alto fator de impacto dos periódicos selecionados, seus artigos publicados poderiam utilizar as normas com maior frequência. Este estudo deve alertar os editores de periódicos a incentivar os autores a consultar as normas disponíveis para apoiar a metodologia dos trabalhos científicos.

Eficácia de diferentes técnicas de obturação no preenchimento de canais laterais simulados û estudo in vitro / Effectiveness of different filling techniques for filling of simulated lateral canals û in vitro study

Este estudo teve como objetivo avaliar, in vitro, a capacidade de diferentes técnicas de obturação no preenchimento de canais laterais artificiais em dentes extraídos usando recurso de imagem. Trinta dentes humanos extraídos (unirradiculares) foram selecionados, a porção coronária foi removida e o comprimento de trabalho foi determinado 1 mm aquém do forame apical. Dois canais laterais foram criados, um no terço médio e um terço apical, em cada raiz. Após o preparo químico-mecânico utilizando técnica escalonada com limas manuais, os dentes foram divididos em 3 grupos (n=10) de acordo com a técnica de obturação utilizada: G1-condensação lateral; G2- técnica híbrida de Tagger e G3- técnica do cone único. Em todos os grupos foram utilizados cones de guta-percha e cimento à base de óxido de zinco e eugenol. Após sete dias de armazenamento, radiografias pós-operatórias foram realizadas e as imagens foram projetadas para avaliação da qualidade da obturação dos canais laterais. Os dados foram submetidos à análise estatística pelo teste de Kruskal Wallis com nível de significância de 5%. A técnica híbrida de Tagger preencheu 35% dos canais laterais simulados, seguida pela técnica da condensação lateral (30%) e pela técnica do cone único (25%). No entanto, a análise estatística não revelou nenhuma diferença significativa na capacidade para preencher os canais laterais entre os grupos (p> 0,05). Embora a técnica híbrida de Tagger associada ao cimento endodôntico tenha apresentado uma incidência maior de preenchimento de canais laterais, as outras técnicas também apresentaram capacidade de proporcionar o selamento dos canais laterais simulados...

The purpose of this study was to evaluate, in vitro, the ability of different filling techniques for filling simulated lateral canals in extracted teeth using image resource. Thirty extracted single-rooted human teeth were selected, the coronal portion was removed, and the working length was established 1 mm short of the foramen. Two lateral canals were created, one in the middle third and one at the apical third, in each root canal. After chemo-mechanical preparation by the manual instrumentation through step-back technique, the teeth were divided into 3 groups (n = 10) according to the filling technique used: G1 - lateral condensation; G2 - Tagger hybrid technique; G3 - single cone technique. In all groups gutta-percha cones and zinc oxide and eugenol-based sealer were used. After seven days of storage, postoperative radiographs were taken and the images were projected for evaluation of the quality of lateral canal filling. Data were submitted to statistical analysis by Kruskal Wallis test at 5% significance level. The results showed that Tagger hybrid technique filled 35% of simulated lateral canals, followed by lateral condensation (30%) and single cone technique (25%). However, statistical analysis revealed no statistically significant difference in the ability to fill lateral canals among the groups (p>0.05). Although the Tagger hybrid technique associated with endodontic sealer presented a higher incidence to fill lateral canals, the other techniques also had the ability to provide the sealing of lateral canals...